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A Comparison of Outcomes between On-Pump and Off-Pump Beating Heart and Traditional Coronary Artery Bypass Surgeries

1 August 2005


Background/Objective: Three basic modalities exist as options to the surgeon performing coronary artery bypass graft surgery (CABO). Traditional CABO employs cardiopulmonary bypass (CPB) and cardioplegic arrest. In an attempt to avoid complications associated with CPB/global myocardial ischemia as a result of cardioplegic arrest, surgeons are re-exploring performing off-pump beating heart CABO (OffPBH). OffPBH is being revealed as a safe and efficacious procedure. But, not all surgeons are quick to take to this approach. On-pump beating heart CABO COnPBR) is an intermediary procedure which allows the surgeon a hemodynamically stable alternative, while avoiding the issue of global myocardial ischemia and possible reperfusion injury. The purpose of this study was to investigate the outcomes of these three procedures to determine if one has any advantage over the other.

Methods: In a non-randomized consecutive case study, 786 isolated, first-operative CABO patients were looked at for type of procedure performed and the associated post-operative riskadjusted mortality and morbidity. Data was captured according to the Society of Thoracic Surgeons National Adult Cardiac Surgery Database (version 2.52.1). Variables collected. included number of diseased vessels, ejection fraction, number of anastomoses performed, and post-operative length of stay. Incidence of post-operative renal failure, cerebrovascular accident, atrial fibrillation, and return to operating room for re-exploration of bleeding were' also investigated.

Results: OnPBH patients constituted ,39% of total CABO cases, 37% were OffPBH, ,and 24% were traditional CABO. OnPBH patients were found to have the highest pre-operative predicted risk of mortality (3.9%), worst average ejection fractions (48.3%) and greatest average number of diseased vessels (2.88), but overall had the lowest risk-adjusted mortality (2.1 %) as well as the highest average number of bypasses performed (3.5). Traditional CABO patients had the highest risk-adjusted mortality at 3.9%, and spent an average of 37.0 minutes longer on CPB. Traditional CABO patients did, however, see the lowest rate of return to operating room (1.5%), while OffPBH patients saw the highest at 7.0%. In terms of post-operative renal failure, OnPBH patients had the lowest incidence with a rate of 3.6%, while again OffPBH patients did poorest with a rate of 7.0%. OnPBH patients suffered the least post-operative cerebrovascular accident (1.3%), and OffPBH suffered the most of the three groups (4.9%). Traditional CABO patients had the lowest incidence of atrial fibrillation after surgery (23.4%), OffPBH had the highest (29.3%). OffPBH patients did, on the other hand, have the lowest rate of prolonged ventilation after surgery (8.0%), while traditional CABO patients required the most ventilatory support (14.1 %). Finally, OnPBH patients were discharged the earliest of the three groups, having spent an average of 6.89 days in the hospital. The traditional CABO patients spent the longest amount of time in the hospital post-operatively (8.56 days).

Conclusions: In this non-randomized consecutive case study of 786 patients, OnPBH patients had the worst ejection fractions, greatest number of diseased vessels, and worst predicted risk of death from surgery, but were found to have the lowest risk-adjusted mortality rate and fewest post-op complications leading to shorter in-house stays. OnPBH should, therefore, be considered a viable option for those requiring routine CABO.


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