CARDIAC TRANSPLANT REJECTION AND NON-INVASIVE COMON CAROTID ARTERY WALL FUNCTIONAL INDICES
Allograft rejection would entail an increase in certain blood biomarkers and active substances derived from activated inflammatory cells which could influence entire vascular endothelial function and deteriorate arterial wall stiffness. We propose that carotid wall functional indices measured with non-invasive ultrasound could we valuable markers of the subclinical cardiac allograft rejection. Aim. Our goal was to analyze the clinical utility of functional common carotid wall (CCW) variables measured with high-resolution Doppler ultrasound as a non-invasive screening tool for allograft rejection in cardiac transplant patients (pts). Methods. One hundred and seventy one pts included 93 cardiac recipients, 30 dilated cardiomyopathy waiting list pts, and 48 stable coronary artery disease (SCAD) pts without decompensated heart failure were included. Along with resistive index (Ri), pulsative index (Pi), and CCW intima-media thickness (IMT), CCW rigidity index (iRIG) was estimated using empirical equation. Non-invasive evaluation was performed in cardiac transplant recipients prior the endomyocardial biopsy. Results. Neither of Ri, Pi, or CCW IMT were different in studied subgroups. iRIG was significantly lower in SCAD pts when compared to the dilated cardiomyopathy subgroup. The later had similar values with cardiac transplant recipients without rejection. Antibody-mediated and cellular rejection were found in 22 (23.7%) and 17 (18.3%) cardiac recipients, respectively. Mean iRIG in pts without rejection was significantly lower in comparison to antibody-mediated rejection and cell-mediated (5514.7 ± 2404.0 vs 11856.1 ± 6643.5 and 16071.9 ± 10029.1 cm/sec <sup>2</sup>, respectively, p = 0.001). Area under ROC for iRIG was 0.90 ± 0.03 units <sup>2</sup>. Analysis showed that iRIG values above estimated treshold 7172 cm/sec <sup>2</sup> suggested relative risk of any type of rejection 17.7 (95%CI = 6.3-49.9) sensitivity 80.5%, specificity - 81.1%, negative predictive value - 84.3%. Conclusions. Increased carotid wall stiffness is found in patients with both antibody-mediated and cellular cardiac allograft rejection. Non-invasive measurement of carotid artery wall rigidity index with triplex ultrasound is a simple screening tool for risk stratification. Having a functional marker would enable preventive measures to be taken at the early stages.