Blood Warm Reperfusion: A Necessary Adjunct to Heart-Valve Surgery in Low-Risk Patients?

Background: The aim of this prospective, randomized study was to determine whether blood warm reperfusion improves myocardial protection provided by cold crystalloid cardioplegia in patients undergoing first-time elective heart-valve surgery, using cardiac troponin I release as the criterion for evaluating the adequacy of myocardial protection.

Methods: Seventy patients with a left ventricular ejection fraction greater than 40% were randomly assigned to 1 of 2 myocardial protection strategies: 1) cold crystalloid cardioplegia with no reperfusion or 2) cold crystalloid cardioplegia followed by 2-minute blood warm reperfusion before aortic unclamping. Cardiac troponin I concentrations were measured in serial venous blood samples drawn immediately prior to cardiopulmonary bypass and after aortic unclamping at 6, 9, 12, and 24 h.

Results: Randomization produced 2 equivalent groups. The total amount of cardiac troponin I released (7.17+/- 14.8 mg in the crystalloid cardioplegia with no reperfusion group and 5.82+/-4.66 mg in the crystalloid cardioplegia followed by blood warm reperfusion group) was not different (P>0.2). Cardiac troponin I concentration did not differ for any sample in either of the 2 groups. The total amount of cardiac troponin I released was higher in patients who required inotropic support (9.14 +/-16.2 mg) than those who did not (4.73+/-4.52 mg; P=0.009).

Conclusions: Our study shows that adding blood warm reperfusion to cold crystalloid cardioplegia provides no additional myocardial protection in low-risk patients undergoing heart-valve surgery.