CSC Cardiac Surgery Sample 2 — Questions and Answers
Question 1: Which cannulation site is preferred for arterial inflow in patients with severe ascending aortic atherosclerosis?
- Ascending aorta
- Femoral artery
- Axillary artery (Correct answer)
- Innominate artery
Correct answer: Axillary artery
The axillary artery is preferred in patients with porcelain aorta or severe ascending aortic atherosclerosis because it provides antegrade flow and avoids the diseased aorta.
Question 2: During mitral valve repair, the P2 scallop of the posterior leaflet is resected and reapproximated. What additional step is routinely performed to prevent systolic anterior motion (SAM)?
- Chordal transfer
- Ring annuloplasty (Correct answer)
- Anterior leaflet augmentation
- Commissurotomy
Correct answer: Ring annuloplasty
Ring annuloplasty reduces the annular diameter and remodels the mitral valve, which is essential to prevent SAM and ensure durable repair after posterior leaflet resection.
Question 3: A patient on cardiopulmonary bypass develops a sudden increase in arterial line pressure with decreased venous return. What is the most likely cause?
- Aortic dissection
- Venous air lock (Correct answer)
- Pump failure
- Oxygenator failure
Correct answer: Venous air lock
Air entrained into the venous line creates a vapor lock that obstructs venous drainage, leading to high arterial pressure and decreased venous return to the pump.
Question 4: Which conduit has the best long-term patency for coronary artery bypass grafting to the left anterior descending artery?
- Saphenous vein graft
- Radial artery
- Left internal mammary artery (Correct answer)
- Right gastroepiploic artery
Correct answer: Left internal mammary artery
The left internal mammary artery (LIMA) to LAD bypass has over 90% patency at 10 years, far superior to vein grafts, making it the gold standard conduit.
Question 5: In aortic valve replacement, what is the primary advantage of a sutureless bioprosthetic valve?
- Lower cost
- Reduced cross-clamp time (Correct answer)
- Better hemodynamics at large sizes
- Longer durability
Correct answer: Reduced cross-clamp time
Sutureless valves are secured without individual sutures, significantly reducing aortic cross-clamp and cardiopulmonary bypass times, which benefits high-risk patients.
Question 6: What is the most common cause of late failure of saphenous vein coronary bypass grafts beyond 5 years?
- Anastomotic stenosis
- Graft thrombosis
- Intimal hyperplasia
- Atherosclerosis (Correct answer)
Correct answer: Atherosclerosis
Beyond 5 years, atherosclerosis within the vein graft is the dominant mechanism of late graft failure, accelerated by the arterial hemodynamic environment.
Question 7: Which electrolyte abnormality is most commonly associated with cardiac arrhythmias following cardiopulmonary bypass?
- Hyponatremia
- Hyperkalemia
- Hypomagnesemia (Correct answer)
- Hypocalcemia
Correct answer: Hypomagnesemia
Hypomagnesemia is very common after CPB due to hemodilution and urinary losses, and predisposes patients to atrial and ventricular arrhythmias.
CSC Cardiac Surgery Sample 2
Which cannulation site is preferred for arterial inflow in patients with severe ascending aortic atherosclerosis?