Impact of Off-Pump Coronary Artery Bypass Surgery on Graft Patency: Current Best Available Evidence

Abstract

For more than three decades cardiac surgeons have been used to perform delicate coronary anastomoses on cardiopulmonary bypass (CPB). However, the price of a still and bloodless field is ultimately paid by the patients in the form of sequelae of negative effects of CPB including blood trauma, activation of a series of inflammatory responses, nonpulsatile flow, and possible embolization of air or debris. In an attempt to avoid these deleterious effects of CPB, off-pump coronary artery bypass surgery (OPCAB) has been rediscovered and refined. Although abundant evidence is available to suggest that excellent results can be achieved when CPB is avoided, concerns have been raised about quality of anastomosis and graft patency rates after OPCAB surgery. We are currently practicing in an era of evidence-based medicine that mandates the prospective randomized controlled trial (RCT) as the most accurate tool for determining a treatment benefit compared with a control population. This review article attempts to evaluate the current best available evidence from RCTs on the impact of OPCAB surgery on graft patency.

Plasma Nitrate/Nitrite (NOx) Is Not a Useful Biomarker to Predict Inherent Cardiopulmonary Bypass Inflammatory Response

“…Pro‐inflammatory cytokines increase during and after clinical cardiac surgery using CPB with peak concentrations usually occurs 12 to 24 hours after CPB ends. If iNOS activation occurs after cytokines production, increased NOx levels would appear only after 24 hours 2 . It is mandatory to highlight that iNOs expression, and its consequent great NO release, is not immediate to an inflammatory stimulus, the time‐course enzymatic expression varying from three to 20 hours.…”

“…Surgery involving cardiopulmonary bypass induces an inflammatory response due to the contact of blood with the nonphysiological surface 1,2 . Inflammation may increase the production of nitric oxide, either by increasing the activity of constitutive nitric oxide synthase (eNOS) or by inducing inflammation‐specific systems, that is, inducible nitric oxide synthase (iNOS) 3 …”

Off-pump coronary artery bypass grafting in octogenarians

“…However, during the last 10 to 15 years, OPCAB has emerged as a valid alternative. This status of OPCAB is based on the perception that avoiding injurious effects of the CPB improves outcomes and possibly decreases resource utilization and costs (48). High-risk patients including the octogenarians are particularly vulnerable to organ dysfunction due to the deleterious effects of CPB (49).…”

Does Off-Pump Coronary Artery Bypass Grafting Negatively Impact Long-Term Survival and Freedom from Reintervention?

“…Surgeons of low or even moderate OPCAB experience have been found to be predictive of emergency conversion [32] as well as responsible for poor graft patency and incomplete revascularization [33]. The technical difficulty of OPCAB grafting means it involves a steep learning curve that applies to both trainees and consultant surgeons new to OPCAB grafting.…”