Myocardial blood supply through a direct left ventricle-coronary artery shunt is not aided by augmented coronary capacitance.

OBJECTIVES

Left ventricle-coronary artery shunting is proposed as an alternative means of myocardial revascularization when standard methods are not an option. During diastole, however, regurgitant coronary flow to the left ventricle decreases the efficacy of the left ventricle-coronary artery shunt. We investigated whether augmented coronary compliance would improve net forward shunt flow.

METHODS

In 11 anesthetized pigs a specially designed stent was placed through the lateral wall of the left ventricle. Through an arterial graft, it was connected to the proximal left anterior descending coronary artery. A blind stump of the right internal thoracic artery (15 cm) was anastomosed to the distal left anterior descending coronary artery to serve as added coronary compliance chamber. Blood flow was measured in the coronary artery just distal from the left ventricle-coronary artery shunt, as well as in the shunt and in the compliance chamber entrance-exit.

RESULTS

The left ventricle-coronary artery shunt decreased the net forward midcoronary flow to 53% +/- 18% (mean +/- SD) of native flow (8 +/- 4 vs 16 +/- 5 mL/min at baseline, P <.01). The augmented compliance did not significantly increase net forward coronary flow (61% +/- 25% of native flow, P <.01 vs baseline and P =.21 vs left ventricle-coronary artery shunt with normal compliance). The increase in systolic forward flow (53 +/- 23 vs 37 +/- 19 mL/min with normal compliance) was accompanied by a similar increase in diastolic regurgitant flow (-26 +/- 20 vs -16 +/- 16 mL/min).

CONCLUSION

In healthy pigs a left ventricle-coronary artery shunt decreased net forward coronary flow to 53% +/- 18% of native flow. Augmentation of coronary artery compliance did not improve shunt performance.