Revascularization of the Posterior Wall of the Heart by Right Internal Mammary Artery Implantation: A Quantitative Flow Study

Abstract

he anterior wall of the left ventricle has been successfully revascularized by implantation of the left internal mammary artery T [12]. Evidence of new collateral channel formation has been provided by angiography [ll], metabolic studies [6], and direct flow measurements [3]. Significant ischemia is frequently present in the posterior wall of the left ventricle [8], which is less readily revascularized. Several methods for increasing the blood supply to this part of the heart have been proposed, which include the implantation of splenic [2], gastroepiploic [l], or intercostal arteries [7] and arterial [lo] or venous grafts [5]. These procedures, however, have been inconclusive or technically troublesome. This report describes a method for revascularization of the diaphragmatic wall of the left ventricle by implantation of the right internal mammary artery. The surgically induced collateral channels were evaluated by direct blood flow measurements, angiographic mapping, and histological studies. Myocardial tissue perfusion by this blood was determined by arteriovenous differences of oxygen and carbon dioxide tension. METHODS Experimental Preparations. Twenty-six mongrel dogs weighing between 18 and 25 kg. were used in this study. Ten of the dogs served as normal controls without operation. In 8 dogs the right internal mammary artery was implanted into the posterior wall of the left ventricle, and myocardial ischemia was