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A comparison between microsurgery and standard coronary bypass technique of long term patency rates of Saphenous vein grafts

Spagnolo S, Barbato L, Scalise F, Grasso MA, Spagnolo P

Introduction: To improve patency rates in coronary bypass grafting we borrowed from microsurgery the use of the operating microscope allowing a suturing technique that minimizes anastomosis restriction. When compared to the standard technique, microsurgery afforded considerably greater long term vein grafts patency rates. Method: Approximately 50% of venous bypass grafts are occluded within 10 years and recent investigations have shown 30% and 40% occlusion rates respectively 12 and 18 months after the operation. Among the factors accounting for coronary bypass dysfunction and occlusion, defective sutures causing stenosis of the distal anastomosis have been shown to play a relevant role. Based on this consideration, since the early nineties we applied a microsurgical technique to all patients undergoing coronary bypass surgery. In order to evaluate the results obtained with this approach, we compared long term patency rates in two groups of patients who had been previously submitted to coronary bypass grafting by either microsurgery or by the traditional technique. Results: From January 2000 to December 2008, 388 patients who had been submitted to coronary bypass surgery in our or other institutions underwent repeat coronary angiography at the Policlinico di Monza (Italy). In 239 patients (62%) Coronary Artery Bypass Graft (CABG) had been performed in other hospitals by the “standard” technique while in the 149 patients operated at the Policlinico di Monza (38%) revascularization had been completed by the microsurgical approach. Respectively 346 (52%) of the 666 grafts performed with the “standard” technique and 297 of the 354 (83%) grafts performed by microsurgery were patent. Regardless of the conduit used, patency rates were invariably greater when microsurgery was employed. However, due to the relatively limited size of the study population, the difference between the techniques reached statistical significance only when vein grafts were compared. In fact, in the two groups vein grafts patency rates were 38% and 81% respectively (p<0.005). Conclusion: Especially for vein grafts, microsurgery results in significantly greater long term patency rates. Our findings suggest that surgical stenosis induced by inaccurate suturing technique may account for a significant proportion of graft occlusions. This observation bears important clinical implications and suggests that, especially when applied on smaller recipient vessels, distal anastomoses should be performed using microsurgical techniques.