1. Dr Narinder Pal Singh Dr Minati Choudhary
Cardioplegia
Dr Narinder Pal Singh
Dr Minati Choudhary

2. Cardioplegic Strategies
sufficient reduction of oxygen demands
delivery to all cardiac regions
provide unimpaired vision

3. Advantages Immediate arrest Hypothermia Provide substrate Maintain pH
Avoid reperfusion damage
Avoid edema

4. Cardioplegic solutions
1 Electrolyte composition
Intracellular
no/ low conc. of sodium and calcium
Extracell. Na depletion, loss of memb. Pot.
Extracellular
higher conc. of sodium, calcium, Mg
hyperkalemic depol. of cell memb.

5. Calcium 2 pH 3 Osmolality Calcium paradox
solutions devoid of ca2+ should never be used
2 pH
Ischemia-intracellular pH ↓ as lactate accumulates.
Buffers should be added.
3 Osmolality
Important in limiting myocardial edema
Blood- Iso-osmolar
Crystalloid- hypo/ iso / hyper (albumin, mannitol, glucose)

6. Additives KCl Diastolic arrest THAM/Histidine Buffer Mannitol
Osmolality/Free Radical Scavenger
Aspartate/Glutamate
Substrate
MgCl2
Ca2+ antagonist
CPD
↓ free Ca2+ conc
Glucose
Blood
O2 carrying

7. Types of Cardioplegia
crystalloid
blood
(2:1, 4:1, 8:1, blood only)

8. Crystalloid Cardioplegia
Does not contain hemoglobin
Delivers dissolved oxygen only
Can be used only with myocardial hypothermia

9. Intracellular

10. Extra cellular

11. BLOOD CARDIOPLEGIA oxygenated environment.
intermittent reoxy of the heart during arrest.
limit hemodilution when large vol of CP used.
excellent buffering capacity.
osmotic properties.
electrolyte composition and pH are physiologic.

12. endogenous antioxidants and free radical scavengers.
Provides substrate
less complex than other solutions to prepare.
Various forms- warm, cold, hot shot
Better ATP replenish
Lower periop morbidity & mortality

14. Cold Blood Cardioplegia
Advantages
Lowers myocardial oxygen demands
Pitfalls
Hypothermic inhibition of mitochondrial enzymes
Shifts oxyhaemoglobin dissociation curve to left
Activates platelets, leukocytes, complement
Impaired membrane stabilization

15. Warm Induction (resuscitation of the heart)
severe left ventricular dysfunction
cardiogenic shock
preischaemic depletion of energy stores
warm induction showed improved aerobic
metabolism and LV function

16. Warm Reperfusion (hot-shot)
early myocardial metabolic recovery while maintaining electro-mechanical arrest
repletion of energy stores

17. Continuous Warm Cardioplegia
avoidance of direct myocellular injury inflicted by any cold solution or environment
increased rate of perioperative stroke and neurological events (randomised trial-1001 patients)

18. “The heart takes up oxygen over time rather than by dose, so that blood cardioplegic solutions must be delivered over a time interval, rather than by volume”
Buckberg GD
J Thorac Cardiovasc Surg 1991;102:

19. Cardioplegic Temperature
cold (9 0C)
tepid (29 0C)
warm (37 0C)
Hayashida et al- compared cold (8°C), tepid (29°C), or warm (37°C) in 72 pts of CABG.
tepid CP- most effective in reducing anaerobic lactate acid release during the arrest period.
Whether tepid cardioplegia confers better protection over other current methodologies remains to be determined

20. retrograde (coronary sinus) Combined (ante/retro)
Cardioplegic Route
antegrade (aorta)
retrograde (coronary sinus)
Combined (ante/retro)

21. Antegrade Cardioplegia
Initial flow rate 150ml/min/m2
Initial dose ml/kg (upto 1 litre)
Perfusion pressure mm Hg

22. Antegrade Cardioplegia
Advantages
Produces prompt arrest
Pitfalls
poor distribution in coronary patients
poor distribution in patients with AR
risk of ostial injury from direct perfusion
interruption of procedure during mitral surgery

23. Retrograde Cardioplegia
Correct catheter placement
flow rate = 200mL/min
perfusion pressure < 40 mmHg
prevent perivascular haemorrhage and oedema

24. Retrograde Cardioplegia
Advantages
Distribution of CP to regions supplied by occluded/stenosed vessels
Improved subendocardial CP delivery
Flushing of air and/or atheromatous debris
Pitfalls
Shunting of CP into ventricular cavities via Thebesian channels
Perfusion defects especially right ventricle and posterior septal regions

25. Combined (ante/retro)
Studies have demonstrated better myocardial protection
Various techniques
Arrest with antegrade, additional doses given retrogradely with venting of aortic root
Alternating technique-retrograde cardioplegia administered frequently+ interrupted antegrade cardioplegia down each completed graft
Simultaneous method- retrograde continued while antegrade is given down each graft.

28. inadequate protection postop RV dysfn coronary ostial stenosis
COMPLICATIONS
inadequate protection
postop RV dysfn
coronary ostial stenosis
coronary sinus injury
aortic root injury

29. CONTROVERSY
‘ideal’ cardioplegic technique
different crystalloid cardioplegia
crystalloid versus blood cardioplegia
Although recent rand trials - improved metabolic and functional myo preserv with blood CP -decreased mortality and morbidity not consistently demonstrated between blood and crystalloid cardioplegia.

30. Therefore, institutional and the individual surgeon's experience remain the most important determinants of myocardial protection strategy at this moment.

31. Thank you