In vitro effects of L-carnitine on coronary artery bypass grafts

BACKGROUND:

The gold standard treatment for multivessel coronary revascularization is coronary artery bypass grafting. The internal mammary artery and saphenous vein grafts are the conduits most frequently used for these operations. Spasm of arterial and venous grafts is a significant problem during the operation.

OBJECTIVES:

To evaluate the acute in vitro effects of L-carnitine on internal mammary artery and saphenous vein grafts using a tissue bath.

METHODS:

Ten consecutive patients who underwent elective coronary artery bypass grafting were enrolled in the present study (nine men, one woman; mean [± SD] age 62±9.1 years). Samples from left internal mammary artery and saphenous vein grafts were collected from each patient. Submaximal smooth muscle contraction was achieved by adding 1 μM phenylephrine, and L-carnitine was then added to the solution. The concentration-response curves of the vasodilation response were obtained.

RESULTS:

In the internal mammary graft samples, the vasodilation response to L-carnitine was 64.3±11.1% at a concentration of 5 mM. In the saphenous vein graft samples, the vasodilation response to L-carnitine was 41.5±11.4% at a concentration of 5 mM. There was a statistically significant difference (P<0.001) between the response of the internal mammary artery and saphenous vein grafts in the in vitro tissue bath system.

CONCLUSIONS:

These results indicate that L-carnitine is a potential vasodilatory drug for internal mammary artery and saphenous vein grafts.