Randomized flow capacity comparison of skeletonized and pedicled left internal mammary artery

The preferential harvesting technique of the internal mammary artery has been periodically debated. This randomized study evaluated the flow outcome of the skeletonized versus pedicled left internal mammary artery.

Two hundred patients undergoing surgery for left anterior descending coronary artery revascularization were enrolled and randomized to pedicled (n=100) or skeletonized (n=100) harvesting. Intraoperative baseline flow and post adenosine infusion into the left ventricle, hospital outcome, echocardiographic results, and troponin I leakage were analyzed. Noninvasive periodic evaluation of flow was carried out at rest and during intravenous adenosine infusion by transthoracic Doppler ultrasound, and was stratified according to the harvesting technique. Final angiographic evaluation was performed by 64-slice multidetector computed tomography.

Skeletonized left internal mammary arteries demonstrated better flow capacity at rest and during adenosine recruitment perioperatively and at all time points of follow-up. Troponin I leakage was significantly higher in the pedicled group (59 vs 42, p=0.02). Pedicled harvesting (hazard ratio [HR] 3.6, 95% confidence interval [CI] 2.5 to 6.9, p<0.001); indexed left ventricular mass greater than 150 g/m2 (HR 4.6, 95% CI 3.1 to 7.5, p<0.001); and baseline corrected thrombolysis in myocardial infarction frame count greater than 30 (HR 4.4, 95% CI, 3.8 to 7.2, p<0.001) were the most powerful multivariable predictors of graft flow reserve less than 2.0. Postoperative echocardiographic results and clinical and angiographic outcomes were comparable between the two groups.

Skeletonization of the left internal mammary artery, beyond traditional proven advantages, provided significantly higher flow capacity and better graft flow reserve.