Coronary Circulation: Clinical and Anesthetic Relevance

The heart can be imagined as a city where coronary arteries serve as highways delivering essential supplies—oxygen and nutrients—to every neighborhood, representing myocardial regions. Three main routes sustain this city:

• The Right Coronary Artery (RCA)
• The Left Main Coronary Artery (LMCA), which branches into:
• the Left Anterior Descending (LAD) artery
• the Left Circumflex (LCx) artery
• Along with their secondary branches and collateral vessels

Understanding this anatomy is not only fundamental for cardiology but is directly relevant to anesthesia, where intraoperative ischemia, arrhythmias, and hemodynamic compromise frequently reflect coronary supply patterns.

The Right Coronary Artery (RCA)

The RCA travels within the right atrioventricular groove, hugging the right side of the heart.

Areas Supplied:

• Right atrium, including the sinoatrial (SA) node in approximately 60% of individuals
• Right ventricle
• Inferior wall of the left ventricle (posterior region)
• Posterior part of the interventricular septum
• Atrioventricular (AV) node in about 85% of individuals

Clinical Correlation:

RCA occlusion typically results in inferior wall myocardial infarction. Due to its role in supplying both the SA and AV nodes, conduction disturbances such as bradycardia or AV block are common. For anesthesiologists, these patients are at increased risk of perioperative arrhythmias, necessitating the availability of atropine and pacing equipment.

References:

Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy. 8th ed. Wolters Kluwer; 2018.

Standring S, ed. Gray’s Anatomy: The Anatomical Basis of Clinical Practice. 42nd ed. Elsevier; 2020.

Widimsky P, Rohac F, Stasek J. Right coronary artery occlusion—clinical and ECG features. Int J Cardiol. 2007;115(3):343-348.

The Left Main Coronary Artery (LMCA)

The LMCA is the parent vessel of the left system and rapidly divides into the LAD and LCx.

Left Anterior Descending (LAD)

The LAD courses along the anterior interventricular groove between the right and left ventricles.

Areas Supplied:

• Anterior wall of the left ventricle
• Anterior two-thirds of the interventricular septum
• Apex of the heart

Mnemonic: LAD supplies the Left ventricle, Apex, and Dividing septum.

Clinical Correlation:

The LAD is often referred to as the “widow-maker.” Occlusion produces a massive anterior wall myocardial infarction, frequently associated with severe left ventricular dysfunction and cardiogenic shock. In the perioperative setting, this translates into high anesthetic risk, particularly during induction and periods of reduced coronary perfusion.

References:

Netter FH. Atlas of Human Anatomy. 7th ed. Elsevier; 2019.

Antman EM, Braunwald E. ST-elevation myocardial infarction. In: Braunwald’s Heart Disease. 11th ed. Elsevier; 2019.

Hochman JS, Tamis JE, Thompson TD, et al. Sex, clinical presentation, and outcome in patients with acute coronary syndromes. N Engl J Med. 1999;341(4):226-232.

Left Circumflex (LCx)

The LCx curves within the left atrioventricular groove, encircling the heart toward the posterior aspect.

Areas Supplied:

• Lateral wall of the left ventricle
• Left atrium
• SA node in about 40% of individuals
• Occasionally the posterior wall, when the LCx is dominant

Clinical Correlation:

LCx occlusion may result in lateral wall infarction. In dominant circulation, involvement of the posterior wall may occur, leading to more extensive ischemia. Because the SA node is sometimes supplied by the LCx, rhythm disturbances may also complicate the clinical course.

References:

Lilly LS. Pathophysiology of Heart Disease. 6th ed. Wolters Kluwer; 2016.

Gensini GG. Coronary arteriography. Circulation. 1975;51(4):676-682.

Bayés de Luna A, Cino J. Lateral infarction: diagnosis and clinical implications. J Electrocardiol. 2012;45(6):582-588.

Coronary Dominance

Coronary dominance is determined by the origin of the Posterior Descending Artery (PDA), which supplies the posterior interventricular septum.

• Right dominant (85%): PDA arises from the RCA
• Left dominant (8–10%): PDA arises from the LCx
• Co-dominant (5–7%): both RCA and LCx contribute to the PDA

Clinical Relevance:

Dominance is important in assessing the area at risk during coronary occlusion. Patients with left dominance may suffer extensive infarcts when the LCx is compromised. For anesthesiologists, recognizing coronary dominance is critical during perioperative cardiac surgery, where cross-clamping and ischemia patterns depend on these variations.

References:

Angelini P. Coronary artery anomalies—current clinical issues. Tex Heart Inst J. 2002;29(4):271-278.

James TN. Anatomy of the coronary arteries. Circulation. 1965;32(6):1020-1033.

Saremi F, Muresian H, Sánchez-Quintana D. Coronary arteries: normal anatomy and anomalies. Radiol Clin North Am. 2012;50(6):895-910.

Mnemonic for Coronary Supply

R-LAP

• Right Coronary Artery: Lateral atrium, Posterior wall
• Left Coronary System (LAD and LCx): Anterior and Lateral walls

References:

Boudoulas KD, Triposciadis F, Geleris P, Boudoulas H. Coronary artery disease: pathophysiologic basis for diagnosis and management. Hellenic J Cardiol. 2016;57(6):394-404.

Fox KAA, Dabbous OH, Goldberg RJ, et al. Prediction of risk of death and myocardial infarction in the six months after presentation with acute coronary syndrome. BMJ. 2006;333(7578):1091.

Implications for Anesthesia Practice

• Inferior wall infarction (RCA involvement): High likelihood of bradycardia and AV block due to nodal artery involvement. Perioperative readiness with atropine and temporary pacing is essential.
• Anterior wall infarction (LAD involvement): Anticipate severe hemodynamic compromise resulting from impaired left ventricular function. Careful titration of anesthetics, preload optimization, and vasopressor support may be required.
• Impact of coronary dominance: Awareness of dominance assists in interpreting angiographic findings and anticipating ischemic consequences during cross-clamping in cardiac surgery.

References:

Barash PG, Cullen BF, Stoelting RK, et al. Clinical Anesthesia. 9th ed. Wolters Kluwer; 2022.

Miller RD, Eriksson LI, Fleisher LA, et al. Miller's Anesthesia. 9th ed. Elsevier; 2020.

Kertai MD, Bountioukos M, Boersma E, Bax JJ, et al. Aortic cross-clamp time and perioperative myocardial infarction in CABG surgery. Eur J Cardiothorac Surg. 2003;24(6):989-995.

Conclusion

The coronary arterial system is a highly organized network that parallels a city’s roadways, where each major artery sustains vital districts of the myocardium. The RCA, LAD, and LCx provide specific territories, while coronary dominance determines the supply of the posterior regions. For anesthesiologists, detailed knowledge of this anatomy is indispensable, not only for understanding the pathophysiology of myocardial ischemia but also for anticipating intraoperative complications, tailoring anesthetic management, and improving patient outcomes.