Protecting the aged heart during cardiac surgery: the potential benefits of del Nido cardioplegia.
OBJECTIVE
Aged hearts are more vulnerable than mature hearts to reperfusion injury during cardiac surgery because of altered cardiomyocyte Ca(2+) homeostasis. Inasmuch as immature cardiomyocytes have similar properties, a specialized cardioplegic solution (del Nido cardioplegia) designed to protect children's hearts may also be beneficial for elderly patients. Our objective was to evaluate the ability of del Nido cardioplegic solution, containing lidocaine and less Ca(2+) than our standard cardioplegic solution, to protect aged cardiomyocytes during cardioplegic arrest and reperfusion.


METHODS
We used our novel isolated cell model of cardioplegic arrest and reperfusion to compare the effect of del Nido cardioplegic solution with that of our standard cardioplegic solution on intracellular Ca(2+) concentration, contractions, and membrane potential in cardiomyocytes from senescent rat hearts.


RESULTS
The incidence of spontaneous contractions during cardioplegic arrest was lower with del Nido cardioplegia (3/11 vs 9/11 cells; P < .05) than with standard cardioplegia, and contractions could not be induced by field stimulation of cardiomyocytes arrested with del Nido cardioplegia (0/11 vs 9/11 cells; P < .05). Intracellular diastolic Ca(2+) levels were lower during arrest with del Nido cardioplegia (57.10 ± 3.06 vs 76.19 ± 3.45 nmol/L; P < .05). During early reperfusion, a potentially injurious rapid recovery of intracellular Ca(2+) associated with hypercontraction in cardiomyocytes arrested with standard cardioplegic solution was avoided in cells treated with del Nido cardioplegia (81.42 ± 2.99 vs 103.15 ± 4.25 nM; P < .05).


CONCLUSIONS
Del Nido cardioplegic solution has the potential to provide superior myocardial protection in senescent hearts by preventing electromechanical activity during cardioplegic arrest and Ca(2+)-induced hypercontraction during early reperfusion.
O'Blenes
Stacy B
SB
IWK Health Centre, Halifax, Nova Scotia, Canada. stacy.oblenes@iwk.nshealth.ca
Friesen
Camille Hancock
CH
Ali
Ahmad
A
Howlett
Susan
S
D000818:Animals; D002118:Calcium / Q000378:metabolism; D006348:Cardiac Surgical Procedures / Q000009:adverse effects; D016922:Cellular Senescence; D004558:Electric Stimulation; D006324:Heart Arrest, Induced / Q000379:methods*; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials; D009200:Myocardial Contraction / Q000187:drug effects; D015428:Myocardial Reperfusion Injury / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D017680:Potassium Compounds / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors
D017680:Potassium Compounds; C018369:potassium cardioplegic solution; D002118:Calcium