Cardiology Trials

N Engl J Med 2020;382:1395-407 - ISCHEMIA

N Engl J Med 2020;382:1608-16 - ISCHEMIA-CKD

Background: The COURAGE trial, published in 2007, represented a major reversal in cardiovascular medicine. In patients with stable CAD an initial strategy of revascularization plus medical therapy did not reduce the chance of dying or having a heart attack compared to an initial strategy of medical therapy alone.

Prior to these results, patients with stable CAD were routinely managed with an initial invasive approach and the field of cardiology was intensely focused on finding coronary blockages and “fixing” them in symptomatic and asymptomatic patients alike. Thus, it’s not surprising that following results from COURAGE, the practice continued to be vigorously defended and applied routinely in the management of patients with stable CAD.

The first major attempt to reverse the results of COURAGE came from the FAME 2 trial, published in 2012, which tested the hypothesis that patients with stable CAD and an abnormal fractional flow reserve (FFR) in the cath lab would do better with an initial invasive strategy compared to medical therapy alone. The trial was stopped early for efficacy but the positive results were driven entirely by revascularization during follow up - not death or heart attack. The trial was criticized for being stopped inappropriately without providing an answer to whether an early invasive strategy improved hard endpoints compared to initial medical therapy alone. The concepts of “faith healing” and “subtraction anxiety” are useful for understanding the results and limitations of the FAME 2 trial.

The ISCHEMIA trial which began enrolling patients in 2012 sought to overcome limitations of COURAGE and FAME. The investigative aim of the study was to test the hypothesis that in patients with stable CAD and moderate to severe ischemia on provocative testing, an initial invasive strategy reduced a composite of major cardiac events compared to initial medical therapy alone.

The ISCHEMIA-CKD trial was performed in conjunction with the ISCHEMIA Research Group to address an important knowledge gap in managing patients with CAD. Patients with advanced chronic kidney disease (CKD) experience a higher rate of cardiac events than their counterparts without CKD; however, they are also at a higher risk of procedural complications. The standard of care at the time was generally to manage a patient with stable CAD and CKD like any other patient with CAD despite the fact that such patients were historically excluded from participation in clinical trials and thus, there was really no data from clinical trials to guide decision making.

The ISCHEMIA-CKD investigators sought to test the hypothesis that in patients with advanced CKD and stable CAD and moderate to severe ischemia on stress testing, an initial invasive strategy reduced death or MI compared to initial medical therapy alone.

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Patients: For the ISCHEMIA trial, eligible patients had to be at least 21 years of age or older with at least moderate ischemia on a qualifying stress test based on the following criteria:

* Nuclear perfusion with SPECT or PET with >/= 10% ischemic myocardium

* Echocardiography with >/= 3/16 segments with stress-induced severe hypokinesis or akinesis

* Cardiac MRI with >/= 10% ischemic myocardium on perfusion imaging and/or >/= 3/16 segments with stress-induced severe hypokinesis or akinesis on wall motion assessment

* Exercise treadmill test without imaging that met all 4 following criteria

* clinical history of typical angina or typical angina during the stress test

* absence of resting ST depression > 1.0 mm or confounders that render exercise EKG non-interpretable (LBBB, LVH with repolarization, pacemaker, etc.)

* exercise-induced horizontal or downsloping ST depression >/= 1.5 mm in 2 leads or >/= 2.0 mm in any lead or ST elevation >/= 1.0 mm in a non-infarct territory

* either of the following:

* workload at which ST segment criteria are met is NOT to exceed completion of stage 2 of a standard Bruce protocol or 7 METS if a non-Bruce protocol is used

* ST segment criteria are met at <75% max predicted HR

The option of exercise treadmill testing without imaging was approved in 2014 to improve recruitment and generalizability of the trial results. This is the predominant form of stress testing used throughout the world.

There were 28 total exclusion criteria applied, key ones include: GFR <30 ml/min, a recent ACS event, unprotected left main stenosis of at least 50%, a LVEF <35%, NYHA class III or IV heart failure, previous PCI within 12 months or ACS within 2 months, stroke within 6 months, unacceptable angina despite use of medical therapy at maximum acceptable doses, high risk of bleeding, history of noncompliance with medical therapy, and life expectancy less than duration of trial due to non-cardiovascular comorbidity.

Most enrolled trial participants underwent coronary computed tomography angiography (CCTA) to exclude left main disease or nonobstructive disease unless they had renal dysfunction that would preclude such testing or known coronary anatomy.

All participating sites met prespecified quality metrics based on the volume and outcomes of PCI and CABG procedures performed. While individual sites determined whether stress testing results met eligibility, all stress tests were reviewed by independent core laboratories.

Enrollment in ISCHEMIA-CKD began 2 years after initiation of ISCHEMIA and the 2 trials ran in parallel and were conducted at most of the same sites. Eligible patients had to have advanced CKD, defined as an estimated GFR of <30 ml/min, and moderate to severe ischemia using the criteria outlined above. However, in contrast with ISCHEMIA, the use of CCTA was not recommended because of the risk of acute kidney injury and core lab review of stress tests was not performed.

Baseline characteristics: A total of 8,518 patients were enrolled in the ISCHEMIA trial and 5,179 underwent randomization at 320 sites in 37 countries. The median age of patients was 64 years, 77% were men, and 66% were white. Most patients (73%) had hypertension, 42% had diabetes and 10% used insulin. The median LVEF was 60%. The frequency of major morbidities included 4% with heart failure, 4% atrial fibrillation, 3% stroke, 7% cerebrovascular disease, and 4% peripheral artery disease. The estimated GFR was not provided in summary table.

Approximately 90% had a history of angina and approximately 65% had it within 4 weeks of enrollment. The Seattle Angina Frequency score was 81 (SAQ scores range from 0 to 100, with higher scores indicating less frequent angina, better function, and greater quality of life). Angina that was new onset or became more frequent within 3 months of enrollment occurred in 26% of the patients.

For ISCHEMIA-CKD, a total of 802 patients were enrolled and 777 underwent randomization at 118 sites in 30 countries. The median age of patients was 63 years, 69% were men, and 64% were white. Nearly all patients (92%) had hypertension and 57% had diabetes (insulin use not documented in summary table). The frequency of major morbidities included 17% with heart failure, 9% stroke, and 6% peripheral artery disease (atrial fibrillation and cerebrovascular disease not documented in summary table). The median LVEF was 58%. The median GFR was 23 ml/min and 14% of patients had GFR <15 ml/min. The median SAQ score was 79. Less information on pre-enrollment angina was provided compared to ISCHEMIA.

Procedures: In both trials, eligible patients were randomly assigned in a 1:1 ratio to an initial invasive strategy of medical therapy, angiography, and revascularization when feasible or to an initial conservative strategy of medical therapy alone, with angiography reserved for failure of medical therapy.

Those assigned to an invasive strategy underwent angiography within 30 days after randomization and complete revascularization of all ischemic territories if feasible. *Sites were provided prespecified guidelines for performing revascularization, including the use of FFR measurements when available and appropriate. Decisions about the type of revascularization, PCI or CABG, were deferred to the local heart team.

*In the ISCHEMIA-CKD trial, strategies to reduce risk of AKI included customized hydration protocol and a contrast-volume threshold provided to the site on the basis of the patient’s GFR and body weight. There were also protocols for PCI techniques involving the use of ultralow contrast volume or no contrast agent.

Medical therapy consisted of intensive secondary prevention with lifestyle and pharmacologic therapy applied equally in both groups with the use of prespecified treat-to-target algorithms.

Patients were followed at 1.5, 3, 6, and 12 months after randomization and every 6 months thereafter.

Endpoints: The primary endpoint of the ISCHEMIA trial was a composite of death from cardiovascular causes, MI, or hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest.

The original trial design specified that 8,000 patients would undergo randomization with 4 years of follow-up for the primary composite endpoint; however, slow recruitment and lower than expected event rates led to modifications being made. In 2015 (enrollment began in 2012), new power calculations determined that 5,000 patients would have at least 83% power to detect an 18% relative reduction in the 4 year rate of the primary outcomes, based on an assumed rate of 20% in the conservative group (16.4% vs 20%).

*Power was re-estimated in 2018 based on a lower than expected event rate. Thus, the final sample size of the trial (5,178 patients) would confer at least 83% power to detect an 18.5% relative reduction in the primary endpoint, assuming an average follow-up of 3 years and an aggregative 4-year cumulative incidence of 14%. (something in ballpark of 13.25% vs 15%).

For ISCHEMIA-CKD, the primary endpoint was a composite of all-cause death or MI. The original planned sample size of 1,000 patients was revised to 650 patients because of slow recruitment. Power calculation performed in 2015 determined that enrollment of 500 patients and a mean follow-up of 3 years would provide a power of >81% to detect a reduction of 23-27% in the invasive strategy group based on a 4 year event rate of 60-75% in the conservative group.

*Power was re-estimated in 2018 based on a lower than expected event rate. The final sample size of 777 patients conferred a power of 80% to detect a relative reduction in the incidence of the primary endpoint by 22-24% in the invasive strategy group, assuming an aggregate 4-year event rate of 41-48% in the conservative group and an accrual of 240 to 270 events.

Results: The ISCHEMIA trial enrolled 8,518 patients and randomized 5,179. Data on screening to enrollment is provided in the supplemental files. Among the 3,339 (39%) who were excluded following enrollment, the main reasons for exclusion were lack of moderate to severe ischemia, according to stress core laboratory (1,350 [40% of those excluded and 16% of those enrolled]), did not have obstructive CAD (1,218 [36% of those excluded and 14% of those enrolled]), and had unprotected left main disease (434 [13% of those excluded and 5% of those enrolled]).

There were 2,588 patients in the invasive strategy group and 2,591 in the conservative strategy group. The median follow-up time was 3.2 years and approximately 2.0% withdrew or were lost to follow-up in both groups.

Compared to the conservative strategy, the invasive strategy did not significantly reduce the primary composite endpoint (16.4% vs 18.2%; HR 0.93; 95% CI 0.80-1.08) or secondary endpoints. All-cause death was numerically higher in the invasive strategy group but this was not statistically significant (9.0% vs 8.3%; HR 1.05; 95% CI 0.83-1.32).

No statistically significant subgroup interactions were reported for the primary composite endpoint. In the subgroup of patients with new or more frequent angina within 3 months prior to enrollment, who composed 26% of the overall cohort, the invasive strategy did numerically worse compared to the conservative strategy (17.6% vs 15.9%; p=NS). We only point this out based on our anecdotal experience as cardiologists that, to this day, patients with new angina or recent worsening of existing angina, often undergo revascularization without attempting to maximize medical therapy first.

It is also noteworthy to point out the subgroup of patients who did not meet eligibility criteria according to core laboratories, who accounted for 14% of all participants. Such patients appeared to do much worse with the invasive strategy (24.4% vs 16.3%; p=NS) but the CI is very wide for this group, reflecting its small size. We highlight this finding to emphasize the lack of evidence to support revascularization in patients with mildly abnormal stress tests who make up a significant percentage of abnormal stress tests in real life.

The ISCHEMIA-CKD trial enrolled 802 patients and randomized 777 of them. There were 388 in the invasive strategy group and 389 in the conservative strategy group. The median duration of follow-up was 2.2 years and 1.5% withdrew or were lost to follow-up. In the invasive strategy group, 50.2% underwent revascularization over a 3 year period compared to 19.6% in the conservative strategy group.

Compared to the conservative strategy, the invasive strategy did not reduce the primary endpoint of death or MI (36.4% vs 36.7%; HR 1.01; 95% CI 0.79-1.29) nor did it reduce the 5 component composite endpoint used in the ISCEMIA trial (38.5% vs 39.7%; HR 1.01; 95% CI: 0.79-1.29). Furthermore there was no difference in death (27.2% vs 27.8%) or MI (15.0% vs 15.9%). The invasive strategy did increase stroke (6.4% vs 1.6%; HR 3.76; 95% CI 1.52-9.32). The invasive strategy also increased the composite safety endpoint of death from any cause or initiation of dialysis in patients who were not receiving dialysis at baseline (44.8% vs 42.4%; HR 1.48; 95% CI 1.04-2.11). There were no statistically significant subgroup interactions reported.

Conclusion: In patients with stable CAD and moderate to severe ischemia on stress testing, an invasive strategy involving up-front revascularization and optimal medical therapy does not significantly reduce cardiac events or death compared to optimal medical therapy alone. The same is true in patients with advanced CKD; however, there are significant harms to an invasive strategy including a 3.5 times increased risk of stroke. In such patients who are not already on dialysis, an invasive strategy increased risk of death or initiation of dialysis.

Neither of the ISCHEMIA trials, involving approximately 6,000 randomized patients, provide evidence for an invasive strategy in patients with stable CAD and moderate to severe ischemia on stress testing. Instead, they join the lineage of negative trials testing up-front revascularization in patients with stable disease performed in the modern era.

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N Engl J Med 2012;367:991-1001

Background: Percutaneous coronary intervention (PCI) did not improve the outcome of death or nonfatal myocardial infarction in stable coronary artery disease, as seen in the COURAGE trial. Nonetheless, some skepticism remained within the cardiology community regarding the results of the COURAGE trial, with the belief that revascularizing ischemia-causing lesions could improve clinical outcomes (ischemic testing was not required in all patients in the COURAGE trial). While there was data supporting this idea, large randomized trials providing conclusive evidence were still lacking.

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Fractional flow reserve (FFR) is a pressure-wire-based measurement performed during coronary angiography to evaluate whether a coronary stenosis is likely to be causing myocardial ischemia.

The investigators of FAME 2 trial sought to test the hypothesis that FFR-guided PCI with drug-eluting stents plus optimal medical therapy (OMT) is superior to OMT alone in patients with stable coronary artery disease.

Patients: Eligible patients had stable angina pectoris and stenosis of 50% or more in at least one major coronary artery that has a diameter of at least 2.5 mm and supplying a viable myocardium. Patients with atypical or no chest pain were included if they had documented ischemia on noninvasive testing. To evaluate the hemodynamic severity of each identified stenosis, FFR was measured using a coronary guidewire during adenosine-induced hyperemia. Patients with at least one stenosis in a major coronary artery with an FFR of 0.80 or less were randomized.

Major exclusion criteria were: Bypass surgery felt to be the preferred treatment strategy, left main disease, myocardial infarction within a week, prior coronary artery bypass surgery, left ventricular ejection fraction <30%, extremely tortuous or calcified coronary arteries or life expectancy less than 2 years.

Baseline characteristics: The trial randomized 888 patients – 447 randomized to the FFR-guided PCI + plus medical therapy and 441 randomized to medical therapy alone.

The average age of patients was 64 years and 78% were men. The average body mass index was 28 kg/m2.  Approximately 78% had hypertension, 76% had hyperlipidemia, 27% had diabetes, 37% had prior myocardial infarction and 20% were current smokers. Sixty one percent had Canadian Cardiovascular Society class II or III angina.

Significant stenosis based on FFR was present in 1 vessel in 76% of the patients, 2 vessels in 21% and 3 vessels in 3%. Among all patients, proximal or middle left anterior descending artery disease was present in 61%.

Procedures: Patients were randomized to undergo PCI using a second-generation drug eluting stent or medical therapy. All patients were prescribed aspirin 80 - 325 mg daily, beta-blockers, ACEi/ ARBs,  statins alone or in combination with ezetimibe, to reduce LDL level to less than 70 mg/dL. Patients who underwent PCI received clopidogrel 600mg followed by 75mg daily for at least 1 year.

Follow up was performed at 1 month, 6 months, 12 months and yearly thereafter.

Endpoints: The primary outcome was a composite of death from any cause, nonfatal myocardial infarction, or unplanned hospitalization leading to urgent revascularization during the first 2 years. Secondary outcomes included individual components of the primary outcome in addition to cardiac death, nonurgent revascularization, and angina class. Outcomes were adjudicated by a committee unaware of treatment assignment. Revascularization was considered urgent when a patient was admitted to the hospital with persistent or increasing chest pain (with or without ischemic EKG changes or elevated cardiac biomarkers) and revascularization was performed during the same hospitalization.

Analysis was performed based on the intention-to-treat principle. The estimated event rate of the primary outcome at 24 months was 12.6% in the PCI group and 18.0% in the medical therapy group, corresponding to 30% relative risk reduction with PCI. Using these event rates, a sample size of 1,632 patients would achieve more than 84% power with a two-sided alpha of 0.05.

Results: The study was stopped early due to significant difference in the primary outcome between the PCI and the medical therapy groups.

A total of 1,220 patients underwent FFR, and among them 888 met the inclusion criteria and were randomized. Among the 447 patients assigned to receive PCI, 435 (97.3%) patients underwent the intervention. Among the 441 patients assigned to the medical therapy group, 2 (0.5%) patients erroneously underwent PCI. The mean follow up time was approximately 7 months. Kaplan-Meier curves were provided up to 1 year since the trial was terminated early. Only 13% of the patients completed 1 year follow up.

FFR-guided PCI plus medical therapy was associated with lower rate of the primary composite outcome compared to medical therapy alone (4.3% vs. 12.7%; HR: 0.32; 95% CI: 0.19 - 0.53; p<0.001). This difference was driven by lower rate of urgent revascularization in the PCI group (1.6% vs 11.1%, HR: 0.13, 95% CI 0.06 – 0.30; p< 0.001). There was no significant difference in death from any cause (0.2% vs 0.7%; p= 0.31) or non-fatal myocardial infarction (3.4% vs 3.2%; p= 0.89). Cardiac death was similar (0.2% in both groups). Non-urgent revascularization was lower with PCI (1.6% vs 8.6%, HR: 0.17, 95% CI: 0.08 – 0.39; p< 0.001).

Among the 56 patients who underwent urgent revascularization, 12 (21.4%) patients had the procedure for myocardial infarction, 15 (26.8%) patients had it for unstable angina accompanied by ischemic EKG changes, and 29 (51.8%) patients had it for unstable angina without ischemic EKG changes.

At 12 months, patients in both treatment groups had significant improvement in symptoms. The percentage of patients with angina class II-IV based on the Canadian Cardiovascular Society classification was numerically lower in the PCI group at 1 year, but this did not reach statistical significance.

Subgroup analysis demonstrated one significant interaction. Patients with FFR <0.65 had more benefit with PCI compared to patients with FFR of 0.65 or more (3.1% vs 17.1% and 5.4% vs 8.9%; p for interaction= 0.01).

Conclusion: In patients with stable coronary artery disease and lesions with FFR of 0.80 or less, PCI compared to medical therapy reduced the need for urgent revascularization with a number needed to treat of approximately 11 patients. There was no significant difference in death or nonfatal myocardial infarction.

Despite what seems to be a strong advantage of the FFR-guided PCI strategy, we believe this trial does not justify its routine use for several reasons. First, the trial did not show any significant improvement in hard outcomes, such as death or nonfatal myocardial infarction. Second, the trial was terminated early, with only 13% of patients completing 1-year follow up. Most importantly, the endpoint of urgent revascularization was not applicable to most patients in the PCI group, as these patients had already undergone revascularization. This, combined with the awareness of both patients and their physicians regarding who underwent PCI, biased the revascularization endpoint in favor of PCI.

We would like to introduce our readers to the terms “faith healing” and “subtraction anxiety” which are well-explained in relation to revascularization by Rajkumar CA et al. In “Faith healing” patients experience a reduction in symptoms after being reassured by a negative test result. For instance, in the FAME 2 trial, patients with an FFR greater than 0.80 had significant symptom improvement, even without PCI and no significant changes to their medications. In “subtraction anxiety,” physicians knowledge of untreated lesions will trigger series of actions when patients present with symptoms even if they were atypical. For instance, there were 3 reasons a patient could have urgent revascularization—biomarkers, ECG-positivity or symptoms alone. In the control arm (PCI-subtracted), the vast majority of urgent revascularization procedures were due to “symptoms only” vs positive ECGs or enzymes.

As practicing cardiologists, we often see patients who come to the emergency department with chest pain but without myocardial infarction. If these patients have coronary stenosis, it is often assumed to be the cause of their chest pain and is treated. However, if the lesion was already treated using PCI, there is nothing left to intervene on. In the medical arm of this trial, 19.5% of the patients underwent revascularization on follow up compared to 3.1% in the PCI arm, including both urgent and non-urgent cases. In our opinion, this demonstrates a success of medical therapy since around 80% of patients were spared an expensive procedure without increasing their risk of death or myocardial infarction. As we discussed previously in the COURAGE trial, performing PCI on all patients to reduce the future need for revascularization by 15-20% is not cost-effective or practical.

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N Engl J Med 2007;356:1503-1516

Background: By the turn of the 21st century more than 1 million coronary stent procedures were performed each year in the United States and approximately 85% were undertaken electively in patients with stable coronary artery disease.

This pattern evolved without a single clinical trial demonstrating a concrete improvement in hard endpoints with percutaneous coronary intervention (PCI) compared to optimal medical therapy (OMT) alone.

We have already reviewed several of these trials including ACME, RITA-2 and the Atorvastatin vs Angioplasty trial. Each trial was relatively small and none showed a significant benefit for revascularization compared to medical therapy on death or MI.

Previous trials involving PCI compared to standard care or OMT included less than 3,000 patients altogether, did not broadly use intracoronary stents (instead using balloon angioplasty only) and they did not employ what would be considered a contemporary standard of medical management. Thus many questions involving the efficacy and safety of PCI versus OMT alone for managing stable CAD remained unanswered.

The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial was designed to test the hypothesis that up front PCI plus OMT would significantly reduce the risk of death and nonfatal MI compared to OMT alone in patients with stable CAD.

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Patients: Eligible patients had stable CAD defined as either 1) a coronary stenosis of >/= 70% in one or more proximal epicardial coronary arteries and objective evidence of myocardial ischemia (based on the resting ECG or with exercise or pharmacologic vasodilator stress testing) or 2) a coronary stenosis of >/= 80% and classic angina without provocative testing.

Patients were excluded if they had persistent Canadian Cardiovascular Society (CCS) class IV angina, a markedly positive stress test defined by substantial ST-segment depression or hypotensive response during stage 1 of the Bruce protocol), refractory heart failure or cardiogenic shock, an EF

Baseline characteristics: The average age of patients was 61 years of age, 85% were men and 85% were white. The average EF was 61%. The median time from the first episode of angina before randomization was 5 months (median, 3 episodes per week, with exertion or at rest). Fifty eight percent of patients had CCS class II or III angina. Eighty five percent of patients underwent stress testing at baseline. Of these, 70% underwent nuclear imaging. In patients who underwent nuclear imaging, 66% had multiple reversible defects and 23% had a single reversible defect.

Angiographic data is as follows, approximately 30% of patients had single vessel disease, 40% had 2 vessel disease, and 30% had 3 vessel disease. The proportion of patients with proximal LAD disease was unbalanced between groups with the medical therapy group having a significantly higher percentage (37% vs 31%; p=0.01). Eleven percent of all patients had a previous CABG and among these participants 65% had disease in a graft.

Procedures: Patients were randomly assigned to undergo PCI and OMT (PCI group) or OMT alone (OMT group). Patients were stratified by study site and whether they had a previous CABG. All patients received antiplatelet therapy with aspirin (81 to 325 mg per day) or clopidogrel (75 mg per day), if aspirin intolerant. Patients undergoing PCI received aspirin and clopidogrel in accordance with accepted standards. Medical anti-ischemic therapy in both groups included long-acting metoprolol, amlodipine, and isosorbide mononitrate alone or in combination, along with either lisinopril or losartan as standard secondary prevention. All patients received therapy to lower LDL with simvastatin alone or in combination with ezetimibe with a target of 60 to 85 mg/dl. After the LDL target was achieved, an attempt was made to raise the HDL to above 40 mg/dl and lower triglycerides to less than 150 mg/dl with exercise, extended-release niacin, or fibrates, alone or in combination.

In patients undergoing PCI, target-lesion revascularization was always attempted, and complete revascularization was performed as clinically appropriate.

Endpoints: The primary endpoint was a composite of death from any cause and nonfatal MI. Secondary outcomes included a composite of death, MI, stroke, and hospitalization for unstable angina with negative biomarkers. The prespecified definition of MI, whether periprocedural or spontaneous, required a clinical presentation consistent with acute coronary syndrome and either 1) new abnormal Q waves in 2 or more contiguous ECG leads or 2) positive cardiac biomarkers. Silent MI, as detected by abnormal Q waves, was confirmed by a core laboratory and was also included as an outcome of MI.

Intention-to-treat analysis was performed for the primary endpoint and important secondary endpoints. The investigators estimated that a sample size of 2,270 patients, followed for 2.5 to 7 years would be needed to detect a relative 22% difference in the primary composite endpoint (16.4% in the PCI group vs 21% in the OMT group at 3 years). This would provide a power of 85% to detect the anticipated difference with a 2 sided alpha of 5%. The investigators incorporated assumptions about crossover between study groups and loss to follow-up.

Results: A total of 2,287 patients were included in the final analysis (1,149 in the PCI group and 1,138 in the OMT group), which represented 6.4% of all patients screened (N=35,539) and 8.5% of those screened who met the basic inclusion criteria (N=26,862). Among those meeting inclusion criteria, the most common reasons for exclusion were: underwent revascularization within 6 months (17%), had an inadequate EF (18%), had a contraindication to PCI (11%), had a serious coexisting illness (9%), had valvular disease (5%), had class IV angina (5%), had left main coronary stenosis >/=50% (4%).

Patients in the trial were adherent with medical interventions and motivated to improve diet and lifestyle. For all patients, BP and cholesterol were improved and activity levels increased over the course of the study. For example, in the OMT group, baseline SBP and LDL were 130 mm Hg and 102 mg/dl at baseline and declined to 122 mm Hg and 72 mg/dl at 5 years, respectively. Similar reductions were seen in the PCI group. Fifty five percent of patients performed moderate physical activity at baseline and this increased to 77% at 5 years. Dietary adherence improved across the board and smoking decreased.

Patients were followed for a median time of 4.6 years and 9% were lost to follow up with no significant difference between group. Overall, PCI + OMT did not reduce the primary endpoint of death or nonfatal MI compared to OMT alone (19.0% with PCI vs 18.5% with medical therapy; HR 1.05; 95% CI 0.87-1.27). Periprocedural MI was numerically more frequent in the PCI group whereas spontaneous MI was nearly identical between groups (statistics not provided). There were no statistically significant differences noted in any of the endpoints reported with the exception of revascularization during the follow up period, which occurred less frequently in the PCI group (20% vs 30%; p<0.001). *It is worth noting that for patients in the PCI group, 12% did not receive a stent following their randomization assignment.

Subgroup analysis yielded one potentially significant interaction for the primary endpoint. Women appeared to benefit from PCI + OMT vs OMT alone compared to men (18% vs 26% for women compared to 19% vs 18% for men; p for interaction = 0.03). Women represented only 15% of the total cohort and contributed approximately 15% of total events and thus, we suspect this represents a false positive finding due to low power since it also lacks biologic credibility.

Conclusions: In patients with stable coronary artery disease, an up-front strategy of PCI plus OMT is not superior to OMT alone for reducing the risk of death or nonfatal MI. The majority of patients with stable CAD should be treated with OMT alone, as an initial strategy, with PCI reserved for those with inadequate symptom control. One limitation of this trial when viewed through a contemporary lens is the low use of drug eluting stents for revascularization; however, we do not personally believe this detracts from the overall findings.

Some people may interpret the 30% rate of revascularization in the OMT group as a proof of efficacy of an up-front strategy of PCI; however, we disagree. These people should keep in mind that 20% of people in the PCI group were revascularized again as well. Their argument boils down to this, “you should revascularize 100% of people up front to reduce the risk of needing PCI in the future by 10%.” That rationale does not make sense on an individual or societal basis when considering cost, safety or convenience. The only people benefiting from such an approach would be the operators and hospitals.

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N Engl J Med 1999;341:70-76

Background: Percutaneous transluminal coronary angioplasty (PTCA) was widely used in the 1990s for its potential benefit in improving symptoms in patients with stable coronary artery disease, as discussed in the ACME and RITA-2 trials. However, the RITA-2 trial showed that PTCA worsened hard outcomes, and ACME was underpowered for such comparison. At the same time, trials demonstrating the ability of statin drugs to reduce cardiovascular events and improve survival had led to an increase in use of the lipid-lowering drugs.

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The Atorvastatin versus Revascularization Treatment Investigators sought to test the unique hypothesis that atorvastatin is superior to angioplasty in reducing ischemic events in patients with stable coronary artery disease.

*It is important to note that the historical trials of CABG versus medical therapy that led to the widespread adoption of coronary revascularization, in general, were completed prior to the adoption of statin therapy. Thus a weakness of the CABG literature, which we have addressed in detail in prior posts and podcasts, is that the efficacy of CABG is inconsistent at best and medical therapy, at the time, was very limited. This makes this study of atorvastatin versus angioplasty of particular interest.

Patients: Eligible patients had stenosis of 50% or more in one or two coronary arteries and had been recommended for treatment with percutaneous revascularization. The patients were asymptomatic or had Canadian Cardiovascular Society (CCS) class I or II angina. LDL levels had to be least 115 mg/dL and triglyceride levels of 500 mg/dL or less.

Patients were excluded if they had left main coronary artery disease, 3-vessel disease, unstable angina or myocardial infarction within the previous 2 weeks, or if the ejection fraction was <40%.

Baseline characteristics: The trial randomized 341 patients – 177 randomized to the PTCA arm and 164 to the atorvastatin arm.

The average age of patients was 59 years and 84% were men. Approximately 45% had hypertension, 16% had diabetes, 42% had prior myocardial infarction and 22% were current smokers. The average ejection fraction was 61%.

At the time of enrollment, 22% were taking lipid lowering drugs and 21% were taking aspirin or other anticoagulants.

Approximately 57% had single vessel disease, while the rest had 2-vessel disease. More patients in the atorvastatin arm had their target lesion in the left anterior descending artery (43% vs 30%).

Procedures: Patients were randomized to coronary angioplasty versus atorvastatin 80mg PO daily. Randomization was stratified based whether patients have single or 2-vessel disease. Patients assigned to the atorvastatin arm stopped other lipid lowering medications. Patients assigned to the angioplasty arm received the usual care at the time, which could include a lipid lowering drug.

Patients were followed up for 18 months.

Endpoints: The primary outcome was an ischemic event defined as at least one of the following: Death from cardiac causes, resuscitation after cardiac arrest, nonfatal myocardial infarction, cerebrovascular accident, coronary-artery bypass grafting, angioplasty, and worsening angina with objective evidence of ischemia resulting in hospitalization. Secondary endpoints included angina based on the Canadian Cardiovascular Society classification and anti-anginal drugs use.

Ischemic events were adjudicated by a committee blinded to treatment assignment. However, this was not the case for the endpoint of angina.

Analysis was performed based on the intention-to-treat principle. The authors reported that the sample size was planned to achieve 85% power at an alpha level of 0.05. This was based on an assumed event rate for the primary outcome over 18 months of 20% in the atorvastatin arm and 35% in the angioplasty arm, this represents a relative difference of approximately 43%. Stated differently, the trial had 85% power to detect a 43% reduction in events for the atorvastatin group.*

The authors performed 2 interim analyses. Consequently, the significance level for the final analysis of the ischemic events endpoint was reduced from 0.05 to 0.045.

Results: No patients were lost to follow up at the 18 months mark. One patient (0.6%) in the atorvastatin arm did not receive atorvastatin and 11 (6%) patients in the angioplasty arm did not undergo the procedure. The number of treated lesions in the angioplasty arm was 213, with stenting used in 64 of them. At the end of the study, 69% of the patients in the angioplasty arm were using a lipid lowering drug and 93% of patients in the atorvastatin arm were still using it. The reduction in LDL levels at the end of study compared to baseline was 18% in the angioplasty arm and 46% in the atorvastatin arm.

There were less ischemic events with atorvastatin (13.4% vs 20.9%; p= 0.048) - this difference did not reach the level of significance as adjusted for the interim analyses; p=0.045. The reduction in events was driven by less coronary artery bypass surgery with atorvastatin (1.2% vs 5.1%) and less worsening angina with objective evidence of ischemia resulting in hospitalization (6.7% vs 14.1%).  Death from cardiac causes was unchanged (0.6% in both treatment groups). Non-fatal myocardial infarctions were not significantly different between both groups (2.4% with atorvastatin vs 2.8% with angioplasty).

More patients in the angioplasty arm experienced reduction in angina (53.7% vs 40.9%; p= 0.009). The use of anti-anginal drugs was similar in both groups at the beginning as well as at the end of the study; approximately 90% at both time points.

Conclusion: In patients with single or 2-vessel stable coronary artery disease, atorvastatin 80 mg daily did not significantly reduce ischemic events compared to an initial strategy of angioplasty.

It may be tempting for readers to interpret these findings as: a strategy of statin therapy is as effective or non-inferior to angioplasty for stable coronary artery disease. Such a framing would be an incorrect interpretation of the trial—in our opinion.

The trial was specifically designed to assess whether atorvastatin was superior to angioplasty, and, strictly speaking, it did not meet the prespecified criteria to claim superiority.

Looking beyond the strict (p-value driven) interpretation of the results, the trial design was very limited. It was a small trial (N=341) that tested for an unrealistically large difference in events (15% absolute risk reduction, 43% relative risk reduction), over a relatively short period, using a composite endpoint consisting of multiple hard and soft outcomes. Furthermore, it’s prespecified analysis overestimated event rates nearly two-fold.

We believe, therefore, that this should be considered a negative trial that yields little actionable information for patient care.

It makes our series because it has historical significance in terms of trying to understand the widespread adoption of angioplasty.

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Lancet 1997;350(9076):461-468

Background: In the ACME trial, percutaneous transluminal coronary angioplasty (PTCA) improved symptoms in patients with single-vessel stable coronary artery disease, but it did not lead to reduction in myocardial infarction or mortality, which were not primary endpoints and the study was under powered for these endpoints. The available data on the efficacy of PTCA for reducing hard endpoints were limited. Moreover, the findings from surgery trials had been inconsistent, as discussed in prior reviews.

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The second Randomized Intervention Treatment of Angina (RITA-2) trial sought to test the hypothesis that coronary angioplasty compared to medical therapy improves outcomes in patients with coronary artery disease.

Patients: Eligible patients were recruited from the United Kingdom and Ireland. Patients had to have significant stenosis amenable to dilation, in at least one major coronary artery. A significant coronary lesion was defined as a 50% or greater diameter stenosis in at least two radiographic projections or at least 70% diameter stenosis in one projection.

Patients were not required to have current symptoms. Patients with multivessel coronary disease, occluded coronaries or who had abnormal left ventricular function were allowed to be enrolled, as well as patients with unstable angina if the most recent episode was at least 7 days before randomization. Patients were excluded if they had left main disease, prior revascularization procedure or recent myocardial infarction.

Baseline characteristics: There were about 70,000 patients who underwent coronary angiogram during the recruitment phase. Around, 2,750 patients were eligible and among them 1,018 were randomized – 504 randomized to the PTCA arm and 514 to the medical therapy arm. The main reasons for not randomizing eligible patients were clinician’s decision or patient’s refusal.

The average age of enrolled patients was 58 years and 82% were men. Approximately 47% had prior myocardial infarction and 9% took medications for diabetes.

Approximately 20% reported no angina at the time of randomization. Single-vessel coronary artery disease was present in 60% of the patients, 2-vessel in 33% and 3-vessel in 7%.

Approximately 87% were taking aspirin, 13% were taking lipid lower drugs, 67% were taking beta-blockers, 50% were taking calcium channel blockers, and 44% were taking long acting nitrates.

Procedures: Patients were randomized to coronary angioplasty or medical therapy. Randomization was stratified by center, extent of coronary disease and the presence of recent unstable angina. PTCA was to be performed within 3 months of randomization. In patients with multivessel disease, not all lesions had to be dilated. Multivessel dilatation could be staged over more than one procedure. Conventional balloon dilatation was the intended strategy, but stents were permissible if the initial angioplasty result was unsatisfactory.

Aspirin was recommended in all patients. Lipid lowering drugs were prescribed at the discretion of the treating physician.

Patients were followed at 3 months, 6 months, then yearly.

Endpoints: The primary endpoint was a composite of all-cause death or non-fatal myocardial infarction at 5-years. Secondary endpoints included unstable angina, heart failure, arrhythmias, angina based on the Canadian Cardiovascular Society classification, anti-anginal drug use, and exercise duration on a symptom-limited treadmill test.

Analysis was performed based on the intention-to-treat principle. The sample size to achieve 80% power at an alpha level of 0.05 was 1,400. This was based on the assumption that the event rate of the primary outcome is 15% at 5-years in the medical arm, and that PTCA would reduce the primary outcome by 33%. The study enrolled less patients than planned due to slow recruitment.

Results: The median follow up time was 2.7 years. Among the 504 patients randomized to PTCA, the procedure was performed in 417 (93%) patients. Among the 514 patients randomized to medical therapy, 118 (23%) underwent PTCA or coronary bypass surgery.

PTCA increased the risk of the primary composite outcome (6.3% vs 3.3%, RR: 1.92, 95% CI: 1.08 – 3.41; p= 0.02). This difference was primarily driven by more non-fatal myocardial infarction with PTCA (4.2% vs 1.9%; p value not provided). All-cause death was not significantly different between both groups (2.2% with PTCA vs 1.4% with medical therapy; p= 0.32).

No significant differences noted in unstable angina (9.9% with PTCA vs 9.1% with medical therapy; p value not provided), heart failure (1.6% with PTCA vs 2.9% with medical therapy; p= 0.15) or arrhythmias (3.0% with PTCA vs 1.4% with medical therapy; p= 0.08).

Symptoms improved significantly in both treatment groups. The improvement in symptoms was greater with PTCA at 3 months (16.5% more patients with grade 2+ angina in the medical arm; p< 0.0001) but the difference was smaller at 2 years (7.6% more patients with grade 2+ angina in the medical arm; p= 0.02). These differences disappeared at 3 years. More patients in the PTCA arm were not taking anti-anginal medications at 3 years (36.2% vs 13.8%). PTCA led to greater improvement in exercise time compared to medical therapy but the differences were small (mean difference favoring PTCA was 35s at 3 months and 25s at 1 year).

No subgroup analysis was provided for the primary outcome.

Conclusion: In patients with coronary artery disease without recent myocardial infarction, PTCA compared to medical therapy worsened the primary outcome of all-cause death or non-fatal myocardial infraction with a number needed to harm of approximately 33 patients over 2.7 years follow up. This difference was largely due to more non-fatal myocardial infarction in the PTCA arm. PTCA led to greater improvement in symptoms at 3 months but there were no significant differences at 3 years.

Read the results above and compare our conclusion with the authors’ conclusion: [In patients with coronary artery disease considered suitable for either PTCA or medical care, early intervention with PTCA was associated with greater symptomatic improvement, especially in patients with more severe angina. When managing individuals with angina, clinicians must balance these benefits against the small excess hazard associated with PTCA due to procedure-related complications].

Medical and percutaneous interventions for coronary artery disease have advanced since the publication of this trial. However, reviewing older trials remains crucial to understand the evolution of the cardiology field and why certain interventions are no longer used. Studying the history of these treatments is important because it sheds light on how current practices have been shaped.

This trial serves as a reminder that a bias toward interventions exists in medicine; the authors’ conclusion downplayed the harms associated with PTCA while emphasizing its potential benefits for symptom relief, even though this was not the primary outcome and is highly subject to bias based on the study design. The trial also has reporting bias; subgroup analysis was not provided for the primary outcome but rather for the secondary endpoints of symptom relief and exercise tolerance. Additionally, the effects of PTCA on symptom relief and exercise tolerance were reported at various time points that seem to have been chosen to emphasize the protentional benefits of PTCA.

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N Engl J Med 1992;326:10-16

Background: Revascularization with coronary artery bypass surgery improves symptoms in patients with chronic stable angina as seen in the European Coronary Surgery Study. Percutaneous transluminal coronary angioplasty (PTCA) is less invasive compared to surgery and is associated with less mortality and morbidity. Consequently, its use increased significantly in the late 1980s and early 1990s, driven by its perceived benefits over medical therapy alone due to the ability of PTCA to reduce coronary artery luminal stenosis.

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The Angioplasty Compared to Medicine (ACME) study sought to test the hypothesis that PTCA improves symptoms in patients with single vessel sable coronary artery disease.

Patients: Eligible patients were recruited from Veterans Affairs centers. Patients had to have 70 – 99% stenosis in the proximal two thirds of one major epicardial coronary artery plus one of the following: stable angina pectoris, very positive exercise-tolerance test (ST-segment depression ≥3 mm) or a myocardial infarction within the past 3 months.

Baseline characteristics: The study screened 9,573 patients and among them only 212 (2.2%) were enrolled – 107 randomized to medical therapy and 105 to PTCA. The reasons for patients’ exclusion were provided in table 1 of the manuscript. Some key exclusion criteria were previous CABG, unstable angina, prior PTCA, 3-vessel disease or lesions not suitable for PTCA.

The average age of enrolled patients was 63 years. Approximately 30% had prior myocardial infarction, 53% had hypertension, 18% had diabetes, 1% had congestive heart failure, and 31% were current smokers. There were more employed participants in the PTCA arm 42% vs 29%. The average systolic blood pressure was 136 mm Hg. The average total cholesterol was 230 mg/dl.

The average duration participants did on the treadmill was 8.8 minutes. Approximately 38% had LAD disease, 25% had LCx disease, and 37% had RCA disease.

Procedures: All patients were admitted to the hospital. Anti-anginal medications were stopped for at least 24 hours and exercise stress test that included thallium Scintigraphy was performed. The test was considered positive if there was horizontal or down-sloping ST-segment depression ≥ 1.0 mm in one or more leads measured 80 msec after the J point that occurred during or after treadmill exercise testing. Patients who had angina during the test but did not meet the above criteria could be included if there was evidence on thallium scanning of a reversible defect in the area corresponding to the index lesion. If the test showed ischemia, patients were then assigned to PTCA or medical therapy.

All patients received aspirin 325 mg/day. Patients in the medical arm received one or combination of the following: nitrates, beta-blockers or calcium channel blockers. Patients in the PTCA arm received calcium channel blockers before and for one month after the procedure, and nitroglycerin during and for 12 hours after the procedure.

Patients were followed monthly. Patients were admitted to the hospital 6 months after randomization, for repeat exercise testing and coronary angiogram. For patients in the medical arm, this exercise testing was performed while they continued their anti-anginal medications. In contrast, patients in the PTCA arm stopped their anti-anginal medications for at least 24 hours before the test.

Endpoints: The primary end points were changes in exercise tolerance, angina attacks and the use of nitroglycerin. Change in the degree of stenosis in the index lesion was measured as a secondary endpoint.

Analysis was performed based on the intention-to-treat principle. The sample size to achieve 95% power at an alpha level of 0.05 was 192. This was based on the assumption that PTCA would increase exercise duration by 1-minute compared to medical therapy. To account for potential loss to follow-up, the recruitment goal was set at 200 patients.

Results: Among the 105 patients assigned to PTCA, 95% underwent the procedure, and among them, the procedure was considered successful in 82%. Successful PTCA was defined >20% decrease in percent stenosis of all lesions in which dilation was attempted. Among the 107 patients assigned to medical therapy, 10% underwent PTCA.

The mean duration from randomization to follow-up exercise testing was approximately 7 months. PTCA led to greater increase in exercise time compared to medical therapy alone (2.1 minutes vs 0.5 minutes; p< 0.0001) as well as time to onset of angina (2.6 minutes vs 0.8 minutes; p <0.01). Patients in the PTCA arm had numerically greater reduction in angina episodes (-15/ month vs -7/ month; p= 0.06). Reduction in nitroglycerin use was not significantly different between both groups (-9/ month with PTCA vs -5/ month with medical therapy; p= 0.25).

There was no significant difference in myocardial infarction (4.8% with PTCA vs 2.8% with medical therapy; p= 0.50) or death (0.0% with PTCA vs 0.9% with medical therapy; p= 1.0). The one patient who died in the medical arm died as a result of a PTCA procedure.

The change in degree of stenosis was not significant in the medical arm (77% at baseline vs 75% at 6 months). In the PTCA arm, stenosis was reduced immediately after angioplasty (76% vs 36%) but then increased again at follow up to 54%.

Conclusion: In patients with single-vessel stable coronary artery disease, PTCA improved exercise duration and symptoms compared to medical therapy alone.

The study is limited by small sample size, but more importantly, it was highly selective, with only 2.2% of screened patients being enrolled. It is, however, valuable that the authors provided reasons for patients’ exclusions which helps physicians determine which of their patients would have qualified for the trial.

Another significant limitation is the lack of blinding, which could introduce bias in the assessment of symptoms and exercise capacity. Additionally, the results of PTCA were not durable, and lesions worsened during 6 months follow-up, compared to the initial results achieved.

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N Engl J Med 2011;364:1607-1616

Background: The three pivotal trials of coronary artery bypass graft surgery (CABG) we previously reviewed, largely included patients with normal left ventricular function. Observational studies suggested that CABG improved survival over medical therapy in patients with coronary artery disease and systolic heart failure.

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The Surgical Treatment for Ischemic Heart Failure (STICH) trial sought to test the hypothesis that CABG reduces mortality in patients with coronary artery disease and left ventricular systolic dysfunction.

Of note, the STICH had two hypotheses: medical therapy vs CABG (hypothesis 1) or CABG vs CABG plus surgical ventricular reconstruction (hypothesis 2) “patients in all arms received medical therapy according to the guidelines at that time”. In this review we focus on hypothesis 1. We are also reporting the 5-year results of STICH since that was the primary intended follow up time.

Patients: Eligible patients had coronary artery disease that was amenable to surgery and left ventricular ejection fraction of 35% or less. Patients were excluded if they had recent myocardial infarction, cardiogenic shock within 72 hours of randomization, life expectancy <3 years due to non-cardiac illness, poor treatment adherence, or 50% or more left main disease.

Baseline characteristics: The study enrolled 1212 patients – 602 assigned to medical therapy alone and 610 assigned to medical therapy plus CABG. The average age of patients was 60 years with 88% being men. The median body mass index was 27 kg/m2. Approximately 77% had prior myocardial infarction, 60% had hyperlipidemia, 60% had hypertension, 39% had diabetes, 8% had chronic kidney disease, 8% had prior stroke and 21% were active smokers. Approximately 3% had previous CABG.

NYHA class was II in 52% of the patients and III in 34%. Approximately 30% of the patients had two vessel disease and 60% had three vessel disease. Left main stenosis (50% or more) was present in 3% of the patients and left anterior descending artery stenosis (75% or more) was present in 68%.

Medications at baseline were as follows: beta-blockers in 85%, ACEi or ARB in 90%, potassium-sparing diuretic in 46%, aspirin in 83% and statins in 81%.

Procedures: Patients were randomly assigned to receive medical therapy alone or medical therapy plus CABG. Guideline-based medical treatment and devices were recommended by a lead cardiologist at each center. The surgeries were performed by surgeons who provided data on at least 25 patients with an ejection fraction of 40% or less, in whom they performed CABG, and had an operative mortality of 5% or less.

CABG was to be performed within 14 days after randomization. Patients were followed up at the time of discharge or at 30 days, every 4 months for the first year then every 6 months thereafter.

Endpoints: The primary end point was all-cause death. Secondary endpoints included death from cardiovascular causes and death from any cause or hospitalization for cardiovascular causes.

Statistical analysis was performed based on the intention-to-treat principle. The original sample size was 2,000 patients to be followed for 3 years. Assuming a 3-year mortality of 25% in the medical arm, this would give the study 90% power to detect 25% mortality reduction with CABG. Due to slow enrollment, the sample size was reduced to 1,200 patients and the follow up time was increased to 5 years.

Results: The median follow up time was 56 months. Among the patients assigned to surgery, 555 (91%) underwent CABG, of whom 91% received at least one arterial conduit. Among the patients assigned to the medical arm, 100 (17%) underwent CABG.

CABG did not reduce mortality compared to medical therapy alone (36% with CABG vs 41% with medical therapy, HR, 0.86, 95% CI: 0.72 - 1.04; p=0.12). CABG reduced cardiovascular death (28% vs 33%, HR: 0.81, 95% CI 0.66 - 1.00; p=0.05) and the composite secondary endpoint of death from any cause or hospitalization for cardiovascular causes (58% vs 68%, HR: 0.74, 95% CI: 0.64 - 0.85; p<0.001).

There were no significant subgroup interactions based on baseline characteristics. The hazard ratio with CABG for selected high risk subgroups is as follows: 0.93 for age 65 or above, 0.80 for younger than 65, 0.92 for patients with diabetes, 0.83 for patients without diabetes, 0.79 for 3-vessel disease and 0.82 for left main or left anterior descending artery disease. The hazard ratio for patients without left main or left anterior descending artery disease was 0.97. Hazard ratio was 0.75 for women and 0.87 for men. P for interaction was > 0.20 for the above groups.

Conclusion: In patients with coronary artery disease and left ventricular ejection fraction of 35% or less, CABG did not improve survival compared to medical therapy alone, over 5 years follow up.

This was an important trial since medical therapy and surgical techniques improved significantly since the publication of the three pivotal trials that were published in the 1970s and 1980s. It’s important to appreciate that this trial included a high-risk group; over one third were dead at 5 years. In comparison, the mortality rate in the Coronary Artery Bypass Graft Surgery Trialists Collaboration was 30.5% in the medical arm at 10-years follow up.

An important limitation of the trial is the lack of details regarding the number of patients screened to enrolled, along with the reasons for slow enrollment or characteristics of excluded patients. This makes it difficult for physicians to determine the proportion of their patients who would have been eligible for the trial.

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For full review of the trials, please visit https://cardiologytrials.substack.com/