Risk of renal dysfunction after less invasive multivessel coronary artery bypass grafting

Several centers have established that off-pump, multivessel coronary artery bypass grafting performed via a small thoracotomy (MVST) is feasible. However, this procedure can be challenging when posterolateral coronary targets need to be grafted. We hypothesized that use of cardiopulmonary bypass via peripheral access (MVST-PA) would improve outcomes compared with a completely off-pump approach (OP-MVST).

This was a prospective observational study of patients undergoing OP-MVST (n = 46) versus MVST-PA (n = 45) using bilateral internal mammary artery grafts onto the left anterior descending coronary artery and circumflex/right coronary artery distribution. Hemostasis was quantified by measuring platelet function (aggregometry), chest tube output, thrombolysis in myocardial infarction bleeding score (%hematocrit change at 24 hours), and transfusion requirements. The rate of mortality and major morbidity at 30 days was defined according to The Society of Thoracic Surgeons criteria. Estimated glomerular filtration rate (normalized to baseline levels) was determined daily until discharge.

The OP-MVST versus MVST-PA groups had similar risk factors at baseline and risks of composite morbidity/mortality at 30 days. However, renal failure was significantly increased after OP-MVST (10.87 vs 0%, P = 0.05), and MVST-PA affected hemostasis as evidenced by inhibition of platelet function (latency to response on aggregometry, 29.9 vs 17.9 seconds; P = 0.04) and higher transfusion requirement (2.31 vs 0.85 units of red blood cells/patient, P = 0.04; 55.6% vs 34.8% transfused; P = 0.059). However, 24-hour chest tube output was similar (645 vs 750 mL; P = 0.53).

In comparison with a completely off-pump strategy, use of cardiopulmonary bypass to assist MVST reduced the risk of renal dysfunction with only modest tradeoffs in other morbidities, for example, altered coagulation and higher transfusion requirements. These data justify further study of the effect of MVST-PA on renal complications.