Emergency Coronary Artery Surgery After Failed PTCA: Myocardial Protection with Continuous Coronary Perfusion of Beta-Blocker-Enriched Blood

 

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Abstract

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 ß-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 (ß-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 und January 1998 fifty-five patients (ß-B: n = 12; CP: n = 43) underwent emergency coronary artery bypass grafting within 24 hours after failed PTCA. The mean age in ß-B patients was 62 ± 9 (SD) years, and 33 % were female (CP: 59 ± 9 years, 42% female, p = NS). In ß-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. ß-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 ß-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 ß-B patients died. Postoperative low cardiac Output occurred in only one patient (8%) of the ß-B group and was treated with an intraaortic 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 ß-B patients. Cumulative postoperative dosage of dopamine and dobutamine was 34516 ± 40400 μg/kg and 16221 ± 26678μg/ kg respectively in CP patients. ß-B patients required only 12457 ± 14738μg/kg (p = 0.02) dopamine and 5112 ± 7381μg/kg (p = 0.01) dobutamine. Perioperative myocardial infarction occurred in 53% of the CP patients and 17% of ß-B patients (p = 0.046). Total CK_max was significantly (p = 0.003) higher in CP patients (812 ± 531 U/L) than in ß-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 ß-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.