Is the internal thoracic artery the conduit of choice to replace a stenotic vein graft?

Abstract

Reoperative coronary artery bypass grafting secondary to saphenous vein graft (SVG) stenosis is a mushrooming problem. The internal thoracic artery graft (ITA) provides superior Long-term patency, but its flow is limited and may be inadequate to meet large myncardial demands. To evaluate the efficacy of the ITA as a replacement conduit for a stenotic SVG, 387 consecutive patients undergoing reoperative bypass grafting from 1985 to 1990 with a stenotic SVG to a totally obstructed left anterior descending coronary artery (LAD) were analyzed. The patients were divided into four groups according to the management of the previously placed SVG. Group I (n = 155) underwent graft replacement with a new SVG. Group II (n = 90) received an ITA with the old SVG left intact. In group III (n = 37), an ITA was placed to the LAD with an SVG to the diagonal (old graft interrupted). Group IV (n = 104) had an ITA only to the LAD (old graft interrupted). There were 14 deaths (3.6%). Mortality rate was 7.9% for group IV and 2.1% for groups I through III ( p = 0.01). Multivariate analyses identified advancing age ( p = 0.01), ITA only ( p = 0.01), and female sex ( p = 0.04) as independent predictors of operative mortality. Evidence of hypoperfusion in the distribution of the LAD was present in 19 patients, all of whom were in group IV (18.9%). Predictors of hypoperfusion were moderate/severe left ventricular function ( p = 0.02) and ITA to the LAD with interruption of the old graft ( p = 0.0001). Hypoperfusion syndrome was treated with a new SVG to the LAD in 11 patients, and all but 1 survived; 8 were treated with an intraaortic balloon pump, for a 63% mortality ( p = 0.01). We conclude that replacing a stenotic SVG to a totally occluded LAD with an ITA is associated with increased mortality and increased incidence of hypoperfusion syndrome. Hypoperfusion syndrome is best treated with supplemental vein grafting.