DECREASED VASOMOTOR EFFECT OF ENDOTHELIN ON THE CORONARY-ARTERIES DURING ANGIOPLASTY IN HYPERTENSIVE PATIENTS

To investigate if the response of the contralateral artery during coro nary angioplasty (PTCA) is different in hypertensive than in normotens ive patients and whether this response is related to plasma levels of endothelin-1 (ET-1). We examined the change in ET-1 plasma levels and the reactivity of the left circumflex artery (LCx) during PTCA of the left anterior descending branch in 10 hypertensive and 23 normotensive patients. Peripheral vein blood samples were drawn for ET-1 estimatio n at baseline, after the end of the first balloon inflation, at the en d of PTCA, and 4 h later. Angiograms of the LCx were obtained at basel ine and during the 1(st) balloon inflation. The ET-1 level in hyperten sives increased from 6.81 +/- 3.76 at baseline to 7.54 +/- 4.76 pmol/l (P = n.s.) at the end of PTCA, while in normotensives it increased fr om 8.21 +/- 3.73 to 11.56 +/- 5.04 pmol/l (F = 7.48, P = 0.0002) respe ctively. The LCx distal segment diameter increased from 1.29 to 1.50 m m during balloon inflation in hypertensives, and from 1.44 to 1.53 mm (F = 5.03, P = 0.03) in normotensives. The diameter increase was relat ed to the baseline ET-1 level (r = -0.67, P = 0.005) in the normotensi ves, but not in the hypertensives. Thus, ET-1 has a weaker vasomotion effect on the coronary vasculature in hypertensives than in normotensi ves during PTCA.