Unstable angina and non-ST segment elevation: surgical revascularization with different strategies

European Journal of Cardio-thoracic Surgery 27 (2005) 1043–1050 www.elsevier.com/locate/ejcts Unstable angina and non-ST segment elevation: surgical revascularization with different strategies Francesco Onoratia,*, Marisa De Feob, Pasquale Mastrorobertoa, Antonio di Virgilioa, Antonio Espositoa, Massimo Polistenaa, Attilio Renzullia, Maurizio Cotrufob Cardiac Surgery Unit, Magna Graecia University, Policlinico Mater Domini Via T.C., Catanzaro 88100, Italy b Department of Cardiothoracic Sciences, Second University of Naples, Naples, Italy Received 27 December 2004; received in revised form 31 January 2005; accepted 21 February 2005; Available online 7 April 2005 Abstract Objective: Unstable angina/non-ST elevation myocardial infarction (UA/NSTEMI) still causes significant hospital morbidity and mortality. We evaluated whether surgical outcome can be modified by different myocardial protection strategies. Methods: This was a prospective clinical study conducted in the cardiac surgery units of two university hospitals. Two hundred and sixty-two consecutive patients undergoing CABG for UA/NSTEMI between January 2002 and June 2004 were prospectively divided in three groups: 126 patients underwent on-pump CABG with antegrade blood cardioplegia (Group A); 67 underwent antegrade and retrograde blood cardioplegia (Group B); 69 off-pump CABG (Group C). Hospital outcome was analysed. Differences in outcome variables were detected with ANOVA; Tukey’s multiple comparison test and Tamhane’s T2 test were used when appropriate. Results: Group A showed higher mortality (PZ.001; PZ.014 vs. Group B; PZ.003 vs. Group C) and perioperative myocardial infarction (PZ.001; PZ.016 vs. Group B; PZ.05 vs. Group C). Hospital stay was shorter in Group B and Group C, compared to Group A (PZ.005; PZ.043 and PZ.05, respectively). Group A required higher doses of inotropes compared to Group B and Group C (PZ.0001; PZ.0001 and PZ.03, respectively), whereas Group B and Group C did not require any inotropic support at all (PZ.0001; PZ.002 and PZ.001 vs. Group A, respectively). Total morbidity was higher in Group A (PZ.006; PZ.007 vs. Group B; PZ.005 vs. Group C). Wall motion score index recovered only in Group B (PZ.0001) and Group C (PZ.001). Troponin I was higher in Group A at 12 h (PZ.0001; P!.001 vs. Group B and Group C), 24 (PZ.0001; PZ.001 vs. Group B and Group C), 48 (PZ.0001; PZ.001 vs. Group B, PZ.002 vs. Group C) and 72 h (PZ.0001; PZ.004 vs. Group B; PZ.05 vs. Group C). Conclusions: Isolated antegrade cardioplegia should be questioned in UA/NSTEMI. Outcome using off-pump revascularization was as good as that of combined antegrade and retrograde warm blood cardioplegia. Q 2005 Elsevier B.V. All rights reserved. Keywords: Coronary artery bypass surgery; Cardiopulmonary bypass; Coronary sinus; Retrograde perfusion; Off-pump 1. Introduction Unstable coronary artery disease is a common cause of admission to hospital and urgent or emergent coronary revascularization [1]. Despite anti-thrombotic treatment, many patients still require coronary artery angiography and urgent revascularization, because of coronary anatomy, persistent chest pain, or ongoing ECG changes, despite maximal medical therapy [2]. Moreover, despite substantial advances in perioperative care, hospital mortality remains significant, ranging from 4.6 to 9.2%, especially in patients with triple-vessel disease or left main stem disease and severe angina [3]. Emergency coronary artery bypass grafting (CABG) in the presence of * Corresponding author. Address: Viale dei Pini, 28, 80131 Naples, Italy. Tel.: C39 081 7441531; fax: C39 081 5536350. E-mail address: (F. Onorati). 1010-7940/$ - see front matter Q 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.ejcts.2005.02.032 acute myocardial ischemia is associated with increased risk for postoperative cardiac dysfunction and low cardiac output syndrome [4]. The proportion of patients undergoing urgent coronary artery bypass grafting is increasing significantly, being as much as 48% of all the coronary artery bypass grafting procedures [5]. Two recent trials have clearly demonstrated that patients with unstable angina and non-ST elevation myocardial infarction (UA/NSTEMI) at high or intermediate risk, defined by triple vessel disease, left main stem disease, left ventricle dysfunction and/or diabetes mellitus, will benefit from early surgical therapy [6,7]. Many perioperative features of unstable angina need to be better understood, and the major issue of the myocardial protection is still debated. In patients with acute myocardial ischemia, continuous warm blood cardioplegia has been advocated as a superior myocardial protection in comparison to cold crystalloid cardioplegia [8]. However, warm blood cardioplegia has been found by other authors to be associated with interstitial myocardial edema and temporary cardiac dysfunction [9]. Therefore, well-established myocardial a 1044 F. Onorati et al. / European Journal of Cardio-thoracic Surgery 27 (2005) 1043–1050 2. Materials and methods 2.1. Patients Two hundred and sixty-two consecutive adult patients admitted at our institutions for ongoing UA/NSTEMI, undergoing primary isolated coronary artery bypass grafting between January 2002 and June 2004, were prospectively enrolled in the study UA/NSTEMI was defined according to current ACC/AHA guidelines [11]. The study population was divided in three groups, according to the surgical strategy. Group A (126 patients) consisted of patients undergoing on-pump CABG with only antegrade delivery of warm blood cardioplegia. Sixty-seven patients undergoing on-pump CABG with antegrade and intermittent retrograde warm blood cardioplegia defined Group B. Sixty-nine patients underwent off-pump CABG (Group C). The postoperative protocol following CABG consisted of 12-lead ECG, color-Doppler echocardiography, biochemical markers of myocardial damage (MB-CK mass, Myoglobin, Troponin I). The study protocol was approved by the Institutional Review Board and informed consent was obtained from each patient. Exclusion criteria were associated with cardiac disease (valvular, aortic disease, congenital pathology) or previous cardiac surgery. 2.2. Anesthetic technique Anesthesia was performed by the same group of anesthetists (nZ3) and consisted of propofol infusion at 3 mg/kg per hour and fentanyl administration at 0.10 mg every 20 min. Neuromuscular blockade was achieved with pancuronium bromide. Alpha-adrenergic drugs were used as required to maintain mean systemic arterial pressure between 50 and 60 mmHg. 2.3. Surgical technique Operations were undertaken immediately within 12 h of coronary angiography. Surgery was performed by four surgeons. The assignment criteria to each surgeon were completely random and the choice of surgical strategy was left to the surgeon. In all patients, CABG was performed through a median sternotomy. Left internal mammary artery was harvested as a pedicle and anastomo (...truncated)