CORONARY-ARTERY RESPONSE TO COLD-PRESSOR TEST IS IMPAIRED EARLY AFTER OPERATION IN HEART-TRANSPLANT RECIPIENTS

Objectives. The aim of the present study was to evaluate the coronary vasomotor response to the cold-presser test within 3 months after heart transplantation. Background. Normal epicardial coronary arteries dilate in response to sympathetic stimulation evoked by the cold-presser test. In transplant recipients, abnormal coronary vasomotion has been described shortly after operation. Methods. Fourteen heart transplant recipients were compared 52 +/- 15 days (mean +/- SD) after operation with 10 control subjects. All had angiographically normal epicardial coronary arteries. Coronary blood how velocity was measured with a Doppler catheter placed in the proximal left anterior descending coronary artery. Four segments in each patient were analyzed by quantitative coronary angiography to assess the diameter changes during the cold-presser test and after intracoronary injection of isosorbide dinitrate. Results. Coronary how velocity increased similarly during the cold-presser test in control subjects and in transplant recipients, from 7.5 +/- 2.3 to 11.0 +/- 3.9 cm/s and from 10.3 +/- 3.2 to 13.7 +/- 4.8 cm/s (both p < 0.01). In control subjects, 39 of 40 segments analyzed dilated during the cold-presser test, In transplant recipients, 48 of 56 segments analyzed did not change or constricted. The mean epicardial coronary diameter increased significantly during the cold-presser test in control subjects (+13 +/- 6%, p < 0.001), whereas it did not change significantly in transplant recipients (-2 +/- 9%, p = NS). In transplant recipients, isosorbide dinitrate elicited coronary vasodilation similar to that in control subjects. Conclusion. These data indicate that in human transplanted denervated hearts, coronary vasodilation in response to sympathetic stimulation by cold exposure is impaired shortly after operation.