Real-time contrast-enhanced† sonography (RT-CES) can assess microvascular tissue perfusion using gasfilled microbubbles. The study was performed to evaluate the feasibility of RT-CES in detecting chronic allograft nephropathy (CAN) in comparison to color Doppler ultrasonography (CDUS). A total of 26 consecutive renal transplant recipients were prospectively studied using RT-CES and conventional CDUS. Transplant tissue perfusion imaging was performed by lowpower imaging during i.v. administration of the sonocontrast Optison TM . Renal tissue perfusion was assessed quantitatively using flash replenishment kinetics of microbubbles to estimate renal blood flow A * b (A = peak signal intensity, b = slope of signal intensity rise). In contrast to conventional CDUS resistance and pulsatility indices, renal blood flow estimated by CES was highly significant related to S-creatinine (r = -0.62, p = 0.0004). Determination of renal blood flow by CES reached a higher sensitivity (91% vs. 82%, p < 0.05), specificity (82% vs. 64%, p < 0.05) and accuracy (85% vs. 73%, p < 0.05) for the diagnosis of CAN as compared to conventional CDUS resistance indices. Perfusion parameters derived from RT-CES significantly improve the early detection of CAN compared to conventional CDUS. RT-CES using low-power real-time perfusion imaging is a feasible method to evaluate microvascular perfusion in renal allograft recipients.

In renal allograft recipients, the prolonged treatment with CsA was associated with a significant increase of PWV whereas no further deterioration of large vessel compliance was observed in patients that were switched to EVR 6 months post transplantation. The cardiovascular risk profile in stable de-novo renal allograft recipients might therefore be positively impacted by an early switch of the primary immunosuppressive therapy from CsA to EVR.

These findings demonstrate that coagulation disorders with altered prothrombin time (INR) or platelets do not increase the risk of significant bleeding when inserting a central venous catheter. Therefore, the prophylactic correction of coagulation by transfusion of blood products or coagulation factors is not necessary before central venous catheter insertion.