Conversions in Off-Pump Coronary Surgery

Indian Journal of Thoracic and Cardiovascular Surgery, 2015

Background Intraoperative conversion of off-pump coronary artery bypass grafting (OPCAB) to on-pump coronary artery bypass grafting (ONCAB) has been associated with adverse outcomes. Inspite of several preoperative risk factors reported in the literature, conversion still remains an unpredictable event. This study aims to determine the incidence and predictors of conversion and attempts to evaluate strategies to prevent the same. Methods Between June 2011 to May 2012, out of 994 patients who were planned for elective OPCAB by 8 different surgical teams at our institution, 127 patients underwent intraoperative conversion to ONCAB. We conducted a retrospective analysis of these patients under two groups-ONCAB (n=127) and OPCAB (n=867). Patients undergoing elective ONCAB and emergency OPCAB were excluded from the study. Results The incidence of intraoperative conversion was 12.77 %. Those who underwent conversion had a significantly higher rate of postoperative complications including hospital mortality (9.44 versus 2.42 %). Left ventricular dysfunction, history of myocardial infarction, and left main disease emerged as independent predictors of conversion. Conclusion Association of certain preoperative risk factors can predict the occurrence of intraoperative conversion. Planned and smooth conduct of OPCAB plays a key role to avoid higher mortality and morbidity associated with conversion. If at all unavoidable, a timely conversion can prevent hazards of emergency conversion.

Journal of Cardiac Surgery, 1998

Abstract The surgical outcome of patients requiring conversion to cardiopulmonary bypass (CPB) during myocardial revascularization using the less invasive surgical approach (LISA) was assessed. The LISA was recently introduced as a technique for complete myocardial revascularization without CPB. It combines avoidance of CPB with the versatility of a median sternotomy for access to all coronary vessels. We have previously demonstrated reduced risk-adjusted mortality and complications in off-CPB coronary artery bypass grafting (CABG) using LISA compared to standard myocardial revascularization. From January to December 1997, 1210 patients underwent isolated CABG at our institution. Of these patients, 832 (63%) were scheduled as on-CPB cases and 378 (37%) as off-CPB. Of the off-CPB patients, 48 were converted to CPB. Team A surgeons used LISA as their primary strategy for CABG whereas team B surgeons used off-CPB CABG in selected patients. Conversions were divided in three classes: Class I patients were converted when the surgeon considered complete revascularization impossible off-CPB; Class II patients were converted due to hemodynamic instability during the procedure; and Class III patients were converted due to graft malfunction, determined by flow measurements or clinical evidence. There were four deaths. All had perioperative infarctions and required intra-aortic balloon pump (IABP). Conversion to CPB occurred in up to 25% of patients scheduled for off-CPB CABG. When off-CPB cases are done using the comprehensive LISA technique and modern technology, conversion rates may be reduced to 11%. Conversion is in general well tolerated except when it is instituted for graft malfunction combined with hemodynamic instability or collapse.

European Journal of Cardio-Thoracic Surgery, 2006

Objective: Many studies have described reduced morbidity in hospital and equivalent midterm outcomes with off-pump coronary artery bypass (OPCAB) surgery compared to conventional CABG (CABG-CPB). However, OPCAB is sometimes converted acutely to CABG-CPB. We describe the risk of acute conversion and compare patients' outcomes for acutely converted OPCAB with unconverted OPCAB and CABG-CPB. Methods: Consecutive acute conversions, i.e. OPCAB patients in whom CPB was instituted urgently for hemodynamic or electrical instability, cardiac arrest or uncontrolled bleeding, were compared with propensity-matched unconverted OPCAB and CABG-CPB patients. Relative risks of death and complications in hospital, and subsequent survival were estimated. Results: The risk of acute conversion between 1996 and 2004 was 1.1% (27/2492): 5.1% in the first 2 years, 2.2% in the third year and 0.8% subsequently. Odds ratios for death in hospital compared to unconverted OPCAB and CABG-CPB were 4.4 (95% confidence interval (CI) 0.67-29.1) and 4.7 (95% CI 1.03-21.1), respectively, and ranged from 0 to 4.5 for serious complications. Converted patients had an increased hazard of death for 3 years after surgery compared to unconverted OPCAB (hazard ratio 3.21, 95% CI 1.20-8.59) and CABG-CPB patients (hazard ratio 3.23, 95% CI 1.41-7.39). Conclusions: Experienced OPCAB surgeons have a low risk of acute conversion. Acutely converted patients have a moderately increased risk of death and serious complications in hospital. These risks are difficult to quantify precisely because conversion is rare.

Bosnian journal of basic medical sciences / Udruženje basičnih mediciniskih znanosti = Association of Basic Medical Sciences, 2008

This study investigated outcomes in patients undergoing coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB), who needed conversion to CPB. Between September, 1998 and September, 2003, 1000 CABG procedures were performed in a Cardiovascular Clinic, University Clinical Centre Tuzla. Multivessel CABG were selected arbitrarily for CABG without CPB (OPCAB) or CABG with CPB (ONCAB). Patients who required conversion due to technical difficulty with grafting were performed with ONCAB including cardioplegic arrest. Patients with severe hemodynamic instability and cardiac arrest were performed as ONCAB without crossclamping, while patients converted for mild to moderate hemodynamic instability were given cardioplegic arrest or not, depending on surgeon preference. 493 operations were scheduled and performed as ONCAB (49.3%), 468 as OPCAB (46.8%) and 39 originally scheduled OPCAB operations were converted to ONCAB (7.7% of originally scheduled OPCAB patients or 3.9% of ...

Indian Journal of Thoracic and Cardiovascular Surgery, 2007

Methods: In this study out of 380 planned off-pump coronary artery bypass procedures done between August 2002 to July 2006, 12 patients required emergency conversion, of which three patients were after haemodynamic collapse, and nine patients were semi elective conversions before haemodynamic collapse.

Journal of Cardiothoracic and Vascular Anesthesia, 2003

Objective: Despite recognized hemodynamic derangements during cardiac displacement, most patients appear to tolerate the off-pump procedure well. However, some patients unpredictably become hemodynamically unstable requiring emergency cardiopulmonary bypass or intra-aortic balloon pump support. After an experience of 5,306 multivessel off-pump coronary artery bypasses (OPCABs), this study was undertaken to determine the factors that would identify the patients who were at a higher risk for the procedure.

Journal of Cardiothoracic and Vascular Anesthesia, 2004

The Annals of Thoracic Surgery, 2011

The relative efficacy of off-pump and on-pump coronary revascularization is uncertain. A complication of off-pump surgery which is rarely considered is intraoperative conversion to cardiopulmonary bypass. Consequently, meta-analysis was performed of studies comparing morbidity after converted and nonconverted off-pump coronary revascularization. There were significant increases in the likelihood of stroke, myocardial injury, bleeding, renal failure, wound infection, intraaortic balloon pump requirement, transfu-sion, and respiratory and gastrointestinal complications after conversion. The underlying mechanisms need to be urgently elucidated. Prevention and treatment protocols for conversion warrant serious consideration and the risk of conversion may need to be discussed when obtaining informed patient consent.

2012

OBJECTIVES: Emergent and late conversions form OFF-to-ON pump coronary artery bypass grafting (CABG) have been associated with worse outcomes, however, it remains unclear as to which risk factors are associated with conversion and how to prevent them. METHODS: Among 4718 patients who randomly underwent off-or on-pump CABG, the incidence of off-pump to on-pump cross-over, or 'OFF-to-ON conversion', was 7.9% (186/2356). The primary outcome was a composite of death, stroke, myocardial infarction, or new renal failure requiring dialysis. We assessed the risk factors and outcomes of converted patients. RESULTS: Emergent OFF-to-ON conversions, defined as conversions for hypotension or ischaemia, were required for 3.2% of patients (n = 75), while most elective conversions were due to small or intramuscular coronaries (n = 83). OFF-to-ON converted patients required increased surgery time, blood transfusions, intensive care unit stay, and presented a higher incidence at 1 year of the composite outcome compared with non-converted off-pump patients (all P< 0.01), especially if the conversion was emergent. Conversely, elective conversions outcomes were no different compared with non-converted off-pump patients (P = 0.35). Independent predictors of emergent conversions included higher heart rate or chronic atrial fibrillation, urgent surgery, more grafts planned and surgeon experience with off-pump CABG. CONCLUSION: Emergent OFF-to-ON conversion is associated with worse outcomes compared with elective conversion or no conversion. In the presence of risk factors for emergent conversion, an early and elective conversion approach is a judicious strategy.