CSC Cardiac Surgery Sample 4 — Questions and Answers
Question 1: A bicuspid aortic valve is most commonly associated with which concomitant aortic pathology?
- Aortic root aneurysm
- Ascending aortic dilation (Correct answer)
- Aortic arch hypoplasia
- Infrarenal aortic aneurysm
Correct answer: Ascending aortic dilation
Bicuspid aortic valve is strongly associated with ascending aortic dilation due to shared genetic abnormalities in the aortic wall, independent of hemodynamic effects of valve dysfunction.
Question 2: During minimally invasive mitral valve surgery via right mini-thoracotomy, what is the preferred method of aortic occlusion when the surgeon cannot reach the ascending aorta directly?
- Intracoronary balloon catheter occlusion
- Endoaortic balloon occlusion catheter (Correct answer)
- Femoral artery cross-clamp
- No aortic occlusion is needed
Correct answer: Endoaortic balloon occlusion catheter
An endoaortic balloon occlusion catheter (Heartport) placed via the femoral artery allows intraluminal aortic occlusion and antegrade cardioplegia delivery without direct aortic cross-clamping.
Question 3: What is the most common indication for surgical repair of a ventricular septal defect (VSD) in adults?
- Qp:Qs ratio >1.5:1 with symptoms (Correct answer)
- Eisenmenger syndrome
- Isolated murmur without shunt
- Small membranous VSD with Qp:Qs <1.5:1
Correct answer: Qp:Qs ratio >1.5:1 with symptoms
Adult VSD repair is indicated when the pulmonary-to-systemic flow ratio (Qp:Qs) exceeds 1.5:1 and is accompanied by symptoms or progressive ventricular enlargement.
Question 4: Which cardioplegia strategy provides the longest safe period of myocardial protection during complex cardiac surgery?
- Single-dose cold blood cardioplegia
- Intermittent antegrade warm blood cardioplegia
- Continuous retrograde cold crystalloid cardioplegia
- Intermittent antegrade cold blood cardioplegia with retrograde supplementation (Correct answer)
Correct answer: Intermittent antegrade cold blood cardioplegia with retrograde supplementation
Combined antegrade and retrograde cold blood cardioplegia delivered at intervals provides uniform distribution to all myocardial territories, maximizing protection during prolonged procedures.
Question 5: What is the mechanism of action of aprotinin in cardiac surgery?
- Inhibition of thrombin
- Serine protease inhibition reducing fibrinolysis and platelet activation (Correct answer)
- Reversal of heparin anticoagulation
- Factor Xa inhibition
Correct answer: Serine protease inhibition reducing fibrinolysis and platelet activation
Aprotinin is a broad-spectrum serine protease inhibitor that attenuates fibrinolysis, inflammatory activation, and platelet dysfunction associated with cardiopulmonary bypass.
Question 6: In the Cox-Maze procedure for atrial fibrillation, what is the primary mechanism by which sinus rhythm is restored?
- Electrical cardioversion of the atria
- Creation of lesion lines that eliminate macro-reentrant circuits (Correct answer)
- Ablation of the AV node
- Pulmonary vein isolation alone
Correct answer: Creation of lesion lines that eliminate macro-reentrant circuits
The Maze procedure creates a series of surgical incisions or ablation lines that interrupt all potential reentrant circuits in the atria, forcing electrical impulses to travel in a single directed path from SA to AV node.
Question 7: Which valve position carries the highest risk of prosthetic valve thrombosis if anticoagulation is subtherapeutic?
- Aortic mechanical valve
- Mitral mechanical valve (Correct answer)
- Tricuspid bioprosthetic valve
- Pulmonary bioprosthetic valve
Correct answer: Mitral mechanical valve
Mitral mechanical valves have the highest thrombotic risk among prosthetic valves due to lower transvalvular gradients and higher stagnation of blood flow, requiring stricter INR targets.
CSC Cardiac Surgery Sample 4
A bicuspid aortic valve is most commonly associated with which concomitant aortic pathology?