Plasma endothelin-1 and thrombomodulin levels in coronary sinus during right atrial pacing and percutaneous transluminal coronary angioplasty

Increases in the levels of plasma endothelins (ETs) have been reported after percutaneous transluminal coronary angioplasty (PTCA). To examine the mechanism of this increase, we measured plasma endothelin-1 (ET-1) and thrombomodulin (TM) levels in both the Valsalva sinus (VAL) and the great cardiac vein (GCV) together with oxygen saturation of the GCV (Sat.GCVO2) during right atrial pacing and PTCA. Thirty patients with stenoses in the left anterior descending coronary arteries were enrolled. A fiberoptic pulmonary artery catheter was placed in GCV for monitoring Sat.GCVO2, and blood sampling was repeated before and after each procedure. ET-1 did not increase during pacing, but after PTCA it significantly increased from basal levels to 24.4±8.3 pg/ml in GCV (P<0.01) and 19.3±7.4 in VAL (P<0.05). Basal TM levels in GCV and VAL were significantly higher in diabetic than in non-diabetic patients, but TM did not change during pacing and PTCA. Sat.GCVO2 significantly decreased from the basal level during pacing and PTCA. We speculate that direct endothelial cell damage is more responsible for the increase of ET-1 during PTCA than myocardial ischemia. Our data indicate that ET-1 may be a useful marker for acute endothelial damage, while TM reflects only chronic and general damage of endothelial cells.