CSC Cardiac Surgery Sample 5 — Questions and Answers
Question 1: After aortic valve replacement, a patient develops new complete heart block. Which anatomic structure is most likely injured?
- Left bundle branch near the membranous septum (Correct answer)
- SA node near the right atrium
- Right bundle branch in the moderator band
- AV node in the triangle of Koch
Correct 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.
Question 2: A patient requires redo sternotomy for mitral valve replacement. What is the greatest risk during sternal re-entry?
- Aortic injury
- Injury to adherent right ventricle (Correct answer)
- Pulmonary artery laceration
- Internal mammary artery transection
Correct 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.
Question 3: Which pharmacologic agent is first-line for treating postoperative vasoplegic syndrome (refractory vasodilation) after cardiac surgery?
- Epinephrine
- Vasopressin (Correct answer)
- Phenylephrine
- Dobutamine
Correct answer: Vasopressin
Vasopressin repletes depleted endogenous vasopressin stores and acts on V1 receptors to cause vasoconstriction in catecholamine-refractory vasoplegic syndrome after CPB.
Question 4: What is the preferred surgical approach for repair of an acute Type A aortic dissection in a hemodynamically stable patient?
- Emergency open repair via median sternotomy (Correct answer)
- Thoracic endovascular aortic repair (TEVAR)
- Medical management with beta-blockers
- Fenestration via catheter-based technique
Correct 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.
Question 5: Which intraoperative finding during CABG surgery indicates that a target coronary artery is unsuitable for bypass grafting?
- Vessel diameter of 1.5 mm
- Diffuse intramyocardial course (Correct answer)
- Presence of an endarterectomized segment
- Epicardial fat overlying the vessel
Correct 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.
Question 6: In a patient with severe tricuspid regurgitation and right heart failure, what hemodynamic parameter best reflects right ventricular function improvement after repair?
- Decrease in pulmonary artery wedge pressure
- Decrease in central venous pressure with improved cardiac output (Correct answer)
- Increase in systemic vascular resistance
- Decrease in pulmonary artery systolic pressure
Correct 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.
Question 7: Which factor most strongly predicts operative mortality in patients undergoing cardiac surgery, as captured by the Society of Thoracic Surgeons (STS) risk score?
- Patient age
- Reoperation (redo) status
- Preoperative ejection fraction
- Urgency of surgery (emergent status) (Correct answer)
Correct 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.
CSC Cardiac Surgery Sample 5
After aortic valve replacement, a patient develops new complete heart block.
Which anatomic structure is most likely injured?