Multicenter assessment of coronary allograft vasculopathy by intravascular ultrasound-derived analysis of plaque composition.

BACKGROUND: Coronary allograft vasculopathy is a severe complication of heart transplantation. We used virtual histology intravascular ultrasound to characterize plaque burden and tissue composition over time in heart transplant recipients. METHODS: We recruited patients undergoing heart transplantation in four centers in Europe and the US between 2004 and 2006. We used intravascular ultrasound to obtain morphological plaque measurements and to perform virtual histology in the left anterior descending coronary artery. Data were characterized according to the duration between transplantation and intravascular ultrasound assessment: 24-60, >60-120 and >120-192 months. RESULTS: We assessed vessels from 152 patients (mean age 58 +/- 12 years) a mean of 70 +/- 53 months (range 1 week to 16 years) after transplantation. Plaque burden of >40% was observed in 26% of vessels analyzed, with increases from baseline being seen in all time categories. If assessed >24 months after transplantation, necrotic core and dense calcified volumes were significantly greater than at baseline (P = 0.0005 and P = 0.01, respectively). Time since heart transplantation and donor age and recipient age were independent predictive factors of increased necrotic core content. Necrotic core volume >2.01 mm(3), diabetes mellitus, donor age older than 40 years, follow-up from transplantation longer than 5 years and recipient age older than 58 years were associated with the need for revascularization. CONCLUSIONS: In coronary allograft vasculopathy, plaque burden and composition change over time and seem to affect clinical outcome. This relationship might facilitate identification of high-risk patients in whom the value of more aggressive medical therapy should be tested.

Non-invasive assessment of coronary flow reserve in idiopathic dilated cardiomyopathy: hemodynamic correlations.

BACKGROUND: Impaired vasodilator myocardial blood flow response has been observed in dilated cardiomyopathy (DCMP). However, the mechanisms responsible for this blunted response are not clear. In the present study, we investigated whether the blunted vasodilator flow response is related to indices of left ventricular performance in patients with idiopathic dilated cardiomyopathy. METHODS AND RESULTS: Eighteen DCMP patients and 12 healthy subjects (C) underwent transoesophageal echocardiography within 48 h from cardiac catheterization. Coronary flow velocity reserve (CFR) was measured in the proximal LAD as the ratio of the peak diastolic coronary flow velocity (Vd-M) after intravenous administration of adenosine to peak baseline diastolic flow velocity (Vd-R). Left ventricular (LV) mass index was positively correlated with baseline coronary diastolic velocity (r=0.415; p=0.043) and inversely correlated with coronary flow reserve (r=-0.570; p=0.003). The baseline coronary diastolic velocity was higher in DCMP vs C (56+/-13 cm/s vs 35+/-12 cm/s; p=0.04). In DCMP pts Vd-R positively correlated with end-diastolic wall stress (r=0.654; p=0.01). Vd increased in both C (96+/-32 cm/s; p<0.05 vs baseline) and DCMP patients (108+/-20 cm/s; p<0.01 vs baseline). The CFR was lower in DCMP patients vs C (1.93+/-0.78 vs 2.99+/-1.01; p=0.009). In DCMP pts CFR was negatively correlated with right atrial pressure (r=-0.595; p=0.015), LVEDP (r=-0.576; p=0.015), pulmonary capillary wedge pressure (PCWP: r=-0.772; p<0.001) and positively with ejection fraction (EF: r=0.683; p=0.003). CONCLUSION: Pts with DCMP have lower CFR compared to controls. This blunted CFR is due to higher baseline coronary flow and reflects higher wall stress. The close relation between CFR and EF, PCWP and LVEDP suggests that not only a higher baseline Vd but also compressive forces due to left ventricular dysfunction might be responsible for the observed blunted adenosine-mediated coronary vasodilation.