MYOCARDIAL CONTRAST ECHOCARDIOGRAPHY FOR ASSESSMENT OF PAPAVERINE VASODILATOR RESPONSE IN PATIENTS WITH ANGIOGRAPHICALLY NORMAL CORONARY-ARTERIES AND IN PATIENTS AFTER ORTHOTOPIC HEART-TRANSPLANTATION

Myocardial contrast echocardiography has the potential for assessing c hanges in regional myocardial perfusion. We used this method to compar e papaverine vasodilator response in 10 patients after orthotopic hear t transplantation without acute rejection of left ventricular hypertro phy (HTX) and in 15 patients with angiographically normal coronary art eries (control group). Injections of 2 ml of sonicated iopromid (9 pai red injections in HTX and 24 paired injections in the control group) w ere performed before and after intracoronary application of papaverine (8 or 10 mg) into the left or right coronary artery. From regional ti me-intensity curves, alpha (variable of curve width), area under the c urve (area), peak contrast intensity (Imax) and contrast decay half-ti me (T1/2) were derived by from a gamma variate function. T1/2 increase d from 4.2 +/- 1.2 to 7.2 +/- 4.0 s (p < 0.01) after papaverine in HTX compared to a change from 4.8 +/- 1.0 to 6.0 +/- 1.7 s (p < 0.001) in normal subjects. Alpha decreased in HTX from 0.44 +/- 0.15 to 0.27 +/ - 0.10 s(-1) (p < 0.01) after intracoronary papaverine injection. In t he control group alpha was 0.37 +/- 0.08 s(-1) at rest compared to 0.3 0 +/- 0.08 s(-1) at hyperemic conditions (p < 0.002). Area increased i n HTX from 444 +/- 261 to 910 +/- 732 U . s (p < 0.01) and in normal s ubjects from 352 +/- 171 to 585 +/- 262 U . s (p < 0.001). Hyperemic t o baseline flow ratios for area varied from 0.9 to 3.8 (mean 2.17 +/- 1.11) in HTX compared to 1.76 +/- 0.52 (1.03 to 2.71) in normal subjec ts. The papaverine induced increase in Imax was 28 +/- 56% in HTX (fro m 64 +/- 28 U to 74 +/- 29 U, NS) compared to 41 +/- 37% in the contro l group (from 45 +/- 17 U to 61 +/- 19 U, p < 0.001). Parameters of ti me-intensity curves between the two patient groups were not significan tly different. In conclusion, papaverine vasodilator response in patie nts after orthotopic heart transplantation, as assessed by myocardial contrast echocardiography, is comparable to patients without angiograp hically documented coronary artery disease, indicating a normal myocar dial flow reserve in heart transplant recipients without acute rejecti on or left ventricular hypertrophy.