Cardiac Surgery Sample Flashcards

After aortic valve replacement, a patient develops new complete heart block. Which anatomic structure is most likely injured?

Answer: Left bundle branch near the membranous septum

The left bundle branch courses along the base of the non-coronary and right coronary cusp region of the membranous septum and is at risk during deep suture placement in aortic valve replacement.

A patient requires redo sternotomy for mitral valve replacement. What is the greatest risk during sternal re-entry?

Answer: Injury to adherent right ventricle

After prior cardiac surgery, the right ventricle commonly adheres to the posterior table of the sternum, making it vulnerable to laceration during oscillating saw re-entry.

Which pharmacologic agent is first-line for treating postoperative vasoplegic syndrome (refractory vasodilation) after cardiac surgery?

Answer: Vasopressin

Vasopressin repletes depleted endogenous vasopressin stores and acts on V1 receptors to cause vasoconstriction in catecholamine-refractory vasoplegic syndrome after CPB.

What is the preferred surgical approach for repair of an acute Type A aortic dissection in a hemodynamically stable patient?

Answer: Emergency open repair via median sternotomy

Acute Type A aortic dissection is a surgical emergency; emergency open replacement of the ascending aorta via sternotomy is the only definitive treatment to prevent rupture and malperfusion.

Which intraoperative finding during CABG surgery indicates that a target coronary artery is unsuitable for bypass grafting?

Answer: Diffuse intramyocardial course

An intramyocardial (tunneled) coronary artery runs within the myocardium rather than the epicardial surface, making anastomosis technically difficult or impossible and often precluding bypass.

In a patient with severe tricuspid regurgitation and right heart failure, what hemodynamic parameter best reflects right ventricular function improvement after repair?

Answer: Decrease in central venous pressure with improved cardiac output

A decrease in CVP combined with improvement in cardiac output indicates that right ventricular forward function has improved and venous congestion is resolving after tricuspid repair.

Which factor most strongly predicts operative mortality in patients undergoing cardiac surgery, as captured by the Society of Thoracic Surgeons (STS) risk score?

Answer: Urgency of surgery (emergent status)

Emergent surgery status carries the highest weight in STS risk modeling because it reflects hemodynamic instability, inadequate preoperative optimization, and inability to defer to improve patient condition.