Angiotensin-converting enzyme inhibition restores flow-dependent and cold pressor test-induced dilations in coronary arteries of hypertensive patients.

BACKGROUND

Cold pressor test (CPT)-induced and flow-dependent epicardial coronary artery dilations are impaired in patients with hypertension. ACE inhibition can attenuate sympathetic coronary constriction and potentiate or restore endothelium-dependent relaxations. This study was designed to determine whether the ACE inhibitor perindoprilat can restore normal coronary dilative responses in hypertensive patients.

METHODS AND RESULTS

Coronary vasomotor responses to CPT and to maximal increase of blood flow induced by papaverine were studied in 10 untreated patients with essential hypertension, no other risk factors, and angiographically normal coronary arteries before and after intravenous ACE inhibition by perindoprilat. Diameters of proximal and distal left anterior descending (LAD) and circumflex coronary arteries were measured by quantitative angiography. Estimates of coronary blood flow and resistance index were calculated with an intracoronary Doppler catheter in the distal LAD. Perindoprilat did not modify the hemodynamic responses to CPT and papaverine. In response to CPT, perindoprilat changed the epicardial coronary constriction (-8.4 +/- 5.8%, P < .001) into a significant dilation (+12.0 +/- 6.4%, P < .001). Perindoprilat significantly increased the coronary blood flow (from 33.7 +/- 10.0 to 57.9 +/- 20.5 mL/min, P < .01) and enhanced the decrease in coronary resistance (from 4.28 +/- 1.27 to 2.96 +/- 0.84 mm Hg.mL-1.min-1, P < .001) caused by CPT. Flow-dependent dilation of the proximal LAD was abolished in the control condition and was restored after perindoprilat (12.6 +/- 4.7%, P < .001).

CONCLUSIONS

ACE inhibition restored CPT-induced and flow-mediated coronary artery dilations in patients with essential hypertension. These results indicate that impaired coronary vasomotor responses may be reversible in recently diagnosed hypertension.