myocardial protection

Question 1

Benefits of retrograde myocardial protection

Answer 1

1. uniform distribution of plege even if severe CAD
2. avoids risk of coronary ostial injury by direct cannulation
3. lowers the risk of atheromatous embolization from patent grafts in reop CABG
4. effective in treating air embolism
5. can be given without interrupting the surgical procedure

Question 2

retrograde positioning

Answer 2

within 3 cm of the coronary sinus oriface

Question 3

retrograde flow rate & pressure limit

Answer 3

flow rate of 100-150ml/min; intermittent or continuous

pressure less than 50 mmHg

keep root vent on suction

Question 4

factors that influence the efficacy of retrograde

Answer 4

1. anatomic variations (i.e. coronary veins)
2. persistent LSVC
3. canulation techniue (tranatrial vs. open)
4. cardioplegic solution composition
5. plege temperature
6. time of infusion
7. flow rate

Question 5

when is retrograde indicated?

Answer 5

1. redo CABG (decrease risk of embolization via patent but atherosclerotic vein grafts by cardioplegia)
2. severe coronary artery disease invoving the LM and RCA
3. open aorta and short LM (cant give dirrect ostial)
4. open aorta& small, non-dominant right (cant canulate RCA directly)
5. AI or type A dissection

Question 6

Cons of retrograde

Answer 6

1. no direct communcation between CS adn anterior cardiac veins (RV free wall)
2. inadequate collaterals
3. RCP placed too far in
4. very long aortic clamp time

Question 7

how to repair ruptured CS

Answer 7

repair on an empty arrested heart

can close CS defect primarily w prolene or with pericardial or vein patches