CCP Cardioplegia Delivery Methods 2 — Questions and Answers
Question 1: Which cardioplegia delivery route provides more uniform myocardial protection in the presence of significant aortic regurgitation?
- Antegrade via aortic root
- Retrograde via coronary sinus (Correct answer)
- Selective antegrade via ostia
- Intermittent warm blood cardioplegia
Correct answer: Retrograde via coronary sinus
Retrograde coronary sinus delivery bypasses the incompetent aortic valve, ensuring cardioplegia reaches the myocardium despite aortic regurgitation.
Question 2: During retrograde cardioplegia, the coronary sinus perfusion pressure should generally be maintained below:
- 20 mmHg
- 50 mmHg (Correct answer)
- 100 mmHg
- 150 mmHg
Correct answer: 50 mmHg
Coronary sinus perfusion pressure above 50 mmHg risks coronary sinus rupture and myocardial edema.
Question 3: What is the primary advantage of warm blood cardioplegia ('hot shot') administered just before aortic cross-clamp removal?
- It prolongs myocardial arrest
- It provides aerobic resuscitation and clears ischemic metabolites (Correct answer)
- It reduces the temperature of the myocardium
- It increases potassium concentration in the heart
Correct answer: It provides aerobic resuscitation and clears ischemic metabolites
A warm blood cardioplegia terminal dose ('hot shot') delivers oxygen and substrates to repay the oxygen debt and flush metabolic waste before reperfusion.
Question 4: Which statement best describes 'del Nido' cardioplegia compared to standard blood cardioplegia?
- Del Nido requires more frequent re-dosing intervals
- Del Nido is typically redosed every 20 minutes
- Del Nido is designed for single-dose myocardial protection lasting up to 90 minutes (Correct answer)
- Del Nido uses purely crystalloid without blood
Correct answer: Del Nido is designed for single-dose myocardial protection lasting up to 90 minutes
Del Nido cardioplegia is formulated to provide extended protection from a single dose, often lasting 60–90 minutes, reducing the need for re-dosing.
Question 5: When using integrated (combined) antegrade and retrograde cardioplegia, what is the primary benefit over either method alone?
- Lower potassium requirements
- More complete myocardial distribution overcoming collateral and coronary artery disease limitations (Correct answer)
- Eliminates need for topical cooling
- Reduces total cardioplegia volume required
Correct answer: More complete myocardial distribution overcoming collateral and coronary artery disease limitations
Combined antegrade and retrograde delivery compensates for distribution gaps caused by coronary artery obstructions and poor collateral flow.
Question 6: In continuous warm blood cardioplegia, myocardial arrest is maintained primarily by:
- Hypothermia below 20°C
- Continuous depolarizing blockade with potassium at normothermia (Correct answer)
- Intermittent cold crystalloid flushes
- High magnesium concentration
Correct answer: Continuous depolarizing blockade with potassium at normothermia
Continuous warm blood cardioplegia maintains arrest through persistent hyperkalemic depolarization while providing oxygenated blood at normothermia.
Question 7: A perfusionist notices the coronary sinus catheter balloon has migrated distally during retrograde cardioplegia. What is the most likely consequence?
- Improved left ventricular distribution
- Occlusion of the middle cardiac vein with inadequate myocardial coverage (Correct answer)
- Increased retrograde flow rate
- Decreased coronary sinus pressure
Correct answer: Occlusion of the middle cardiac vein with inadequate myocardial coverage
Distal balloon migration can obstruct major cardiac veins, limiting retrograde cardioplegia distribution and resulting in inadequate myocardial protection.
CCP Cardioplegia Delivery Methods 2
Which cardioplegia delivery route provides more uniform myocardial protection in the presence of significant aortic regurgitation?