Background: Myocardial protection during cardiac surgery in patients with acute ischemia after failed PTCA remains a challenge. Our recent experimental work demonstrated that continuous coronary perfusion with warm beta-blocker-(Esmolol) enriched blood may be a useful alternative to current cardioplegia techniques, especially for compromised hearts. This technique was applied in our last 12 patients after failed PTCA (beta-B). The purpose of this retrospective study was to compare this alternative myocardial protection technique with our standard technique of cold crystalloid cardioplegia (CP).
Methods: Between January 1994 and January 1998 fifty-five patients (beta-B: n = 12; CP: n = 43) underwent emergency coronary artery bypass grafting within 24 hours after failed PTCA. The mean age in beta-B patients was 62+/-9 (SD) years, and 33% were female (CP: 59+/-9 years, 42% female, p = NS). In beta-B patients 67% had myocardial infarction (MI) prior to coronary angioplasty, 67% had an ejection fraction (EF) >55%, and coronary vessel involvement (VI) was 2.1+/-0.7. CP patients had the following findings: MI rate 42%, EF >55% in 84%, VI was 2.2+/-0.6; p = NS. Operation commenced within 25-980 min after failed PTCA. Beta-B patients received 2.7+/-0.8 grafts during 45+/-20 min continuous coronary perfusion with Esmolol enriched blood, whereas CP patients had 3.0+/-1.1 grafts in 42+/-17 min cross-clamp time, p = NS.
Results: The total hospital stay was significantly (p = 0.004) shorter for beta-B patients (18+/-8 days) compared to CP patients (27+/-12 days). 30-days mortality rate was 9% in CP patients, whereas none of the beta-B patients died. Postoperative low cardiac output occurred in only one patient (8%) of the beta-B group and was treated with an intra-aortic balloon pump (IABP). Eight (19%) of the CP patients required an IABP and in five (12%) patients an additional ventricular assist device was necessary (LVAD: n = 4; RVAD: n = 1). The need for circulatory support with inotropes was significantly lower in beta-B patients. Cumulative postoperative dosage of dopamine and dobutamine was 34516+/-40400 microg/kg and 16221+/-26678 microg/kg respectively in CP patients. Beta-B patients required only 12457+/-14738 microg/kg (p = 0.02) dopamine and 5112+/-7381 microg/kg (p = 0.01) dobutamine. Perioperative myocardial infarction occurred in 53% of the CP patients and 17% of beta-B patients (p = 0.046). Total CKmax was significantly (p = 0.003) higher in CP patients (812+/-531 U/L) than in beta-B patients (457+/-265 U/L). Four CP patients (9%) had acute postoperative renal failure requiring hemofiltration, and 11 CP patients (26%) had acute postoperative pneumonia. In beta-B patients one patient (8%) suffered from postoperative pneumonia (p = NS) and no patient had renal failure (p = NS).
Conclusion: These clinical results appear to confirm our experimental data and suggest that continuous coronary perfusion with warm esmolol-enriched blood is superior to crystalloid cardioplegia in terms of in-hospital complications and mortality, especially for compromised hearts after failed PTCA.