CORONARY COMPLIANCE IN PATIENTS FOLLOWING ORTHOTOPIC HEART-TRANSPLANTATION - AN INTRAVASCULAR ULTRASOUND STUDY

Background The aim of this study was to investigate coronary complianc e in patients early and 71.8 weeks after orthotopic heart transplantat ion. Methods Thirty patients (mean age 51.4 years, women n=6) underwen t coronary angiography early after orthotopic heart transplantation (m ean interval 11.6 +/- 5.5 weeks), by which time 12 recipients had alre ady been treated for episodes of rejection. A total of 153 different c oronary segments were investigated using a mechanical 30 MHz intravasc ular ultrasound system. In all segments, the intimal index and the cir cumferential extension of the vessel wall, which had a three-layered a ppearance, were assessed. Systolic-diastolic changes in area, and pres sure with respect to vessel wall area, were used to study normalized c ompliance. All measurements were repeated in a subgroup of 13 patients 71.8 +/- 10.7 weeks after transplantation. Results At the first inves tigation, the mean intimal index of all estimated cross-sectional area s was 0.07 +/- 0.10. The mean circumferential extension of the 'three- layered' coronary vessel wall was 74 degrees +/- 101 degrees. No corre lation could be found between normalized compliance and the intimal in dex (r=-0.322, P<0.001) or between normalized compliance and the circu mferential extension of the three-layered vessel wall (r=-0.362, P<0.0 01). Donor age did not correlate with normalized compliance either (r= - 0.515, P=0.004). In 12 patients with proven rejection periods befor e the first investigation, normalized compliance was significantly low er (1.76 +/- 0.81 mmHg(-1)) than in those without rejection (2.95 +/- 1.22 mmHg(-1), P=0.005). Both the intimal index and the circumferentia ; extension of the three-layered architecture of the vessel wall were significantly higher in recipients with rejection periods. A compariso n of the subgroup of 13 recipients between first and second investigat ion showed that the intimal index increased slightly from 0.03 +/- 0.0 3 to 0.09 +/- 0.13 (ns) 71.8 weeks after transplantation, but that nor malized compliance did not differ significantly between the first and the follow-up investigation. Conclusions Early after orthotopic heart transplantation, normalized compliance does not correlate with donor a ge or the extent of atherosclerotic vessel alterations identifiable by intravascular ultrasound. Early rejection periods are associated with reduced coronary arterial compliance. Using intravascular ultrasound, this adverse functional effect on arterial compliance can be observed together with an increase in the intimal index.