Progressive heterogeneity of myocardial perfusion in heart transplant recipients detected by thallium-201 myocardial SPECT.

UNLABELLED

Progressive graft atherosclerosis is a serious complication in long-term survivors after heart transplantation. Coronary angiography is insensitive with regard to the early and characteristic alterations. We evaluated the progression of these abnormalities and the influence of former rejection episodes.

METHODS

Early after transplantation, 43 patients (34 men, mean age 53.7 +/- 10.7 yr) underwent stress and redistribution 201Tl myocardial SPECT after treadmill exercise. Twenty patients were followed-up to the second postoperative year, and 13 patients to the third postoperative year. Thallium-201 distribution and kinetic abnormalities were documented in a scheme enclosing 20 myocardial segments. Additionally, a score was developed that measured the degree of inhomogeneity of 201Tl distribution and the severity of perfusion defects, respectively.

RESULTS

Regarding scintigraphy, pathologic results could be found in 40% of segments (redistribution, 25%; reverse redistribution, 30%; persistent defects, 49%). Score values in heart transplant recipients differed significantly from normal controls (p < 0.001) and were comparable to patients with single vessel disease of their native hearts. Thallium-201 inhomogeneity in recipients after treatable rejection episodes did not differ from results in recipients without any biopsy-proven rejection. The follow-up of cardiac transplant patients revealed a significant increase of score values up to the third year after transplantation (p < 0.02), despite reproducible normal angiography. There was no direct correlation between score values and IVUS results, although there was a parallel trend in 10 of 12 follow-ups.

CONCLUSION

Despite normal coronary angiography, 201Tl myocardial SPECT frequently revealed pathologic results in heart transplant recipients. Scintigraphic results did not correlate with intimal thickening of epicardial coronary arteries accessible to intravascular ultrasonography in the early phase after transplantation. The presented score of inhomogeneity might reveal progressive disease possibly caused by small vessel alterations.