Determinants of coronary remodeling in transplant coronary disease - A simultaneous intravascular ultrasound and Doppler flow study

Background-Coronary remodeling plays a significant role in lumen loss in tr ansplant allograft vasculopathy (TxCAD), but the determinants of remodeling are unknown. We assessed the relationship between remodeling and plaque to pography, coronary compliance, and blood flow in TxCAD. Methods and Results-One artery in each of 27 transplant patients was invest igated with simultaneous intravascular ultrasound and coronary flow measure ments (basal and hyperemic by Doppler flow wire). At 4 to 8 different cross sections (mean 5.1+/-1.2), plaque topography (concentric or eccentric) was determined, and total vessel area, lumen area, and intimal/medial area (IM A) were measured. Mean remodeling ratio (vessel area/IMA) in eccentric lesi ons (E, n=28) was significantly larger than that in concentric lesions (C, n=70) (E 5.87+/-0.93 versus C 3.58+/-0.62; P<0.001), despite similar IMA (E 3.89+/-0.68 versus C 3.90+/-0.41; P=NS) and distribution of imaged segment s. Remodeling ratio was consistently larger in eccentric lesions in all 3 v essel segments when analyzed separately, and mean remodeling ratio for each artery was larger in vessels with predominantly eccentric lesions. Coronar y compliance ([Delta lumen area/diastolic lumen area]/Delta mean arterial p ressure X 10(3)) was also significantly greater in eccentric lesions versus concentric lesions (proximal 1.00+/-0.39 versus 0.22+/-0.043 mid 0.71+/-0. 17 versus 0.21+/-0.10; distal 0.43+/-0.13 versus 0.01+/-0.08: all P<0.01). Coronary flow reserve was also significantly higher in coronary artel ies w ith primarily eccentric ic lesions (E 2.49+/-0.64 versus C 1.87+/-0.28; P<0 .01). Conclusions-Vessel remodeling in transplant vasculopathy is significantly g reater in eccentric lesions than in concentric lesions, possibly due to gre ater coronary compliance and resistive vessel function.