Initial experience with the use of fractional flow reserve in the hemodynamic evaluation of transplant renal artery stenosis.

ABSTRACT

OBJECTIVE: To describe and standardize an original protocol for fractional flow reserve (FFR) pre and postangioplasty in an initial series of patients with clinically manifested transplant renal artery stenosis (TRAS). BACKGROUND: There is no data in the literature about the use of FFR in TRAS. METHODS: Patients with TRAS detected in a noninvasive study were referred to diagnostic angiography and stenosis considered visually severe (≥ 60%) were included. After selective cannulation, a PressureWire 0.014" (Certus™-St. Jude Medical) was advanced to the distal portion of the vessel. Resting Pd/Pa ratio (ratio of mean distal to lesion and mean proximal pressures) and translesional systolic pressure gradient were obtained and FFR and hyperemic translesional systolic and mean pressure gradients (HSG and HMG) were registered after papaverine induced maximum hyperemia-pre and poststent implantation. Creatinine levels and office blood pressure measurements were registered at the baseline, 6 and 12 months after intervention. RESULTS: Ten consecutive patients had successful stent implantation and were included. After treatment, significant increase in FFR (0.76 ± 0.09 vs. 0.96 ± 0.04, P < 0.001) and reduction in systolic hyperemic gradients (-41.40 ± 19.18, P < 0.001) and mean (-24.00 ± 11.65, P < 0.001) were observed. A strong negative correlation was observed between FFR and percent stenosis diameter-%SD (r = -0.89, P < 0.001) and HSG (r = -0.9, P < 0.001) as well as a strong positive correlation between FFR and baseline Pd/Pa ratio (r = 0.9, P < 0.001). CONCLUSION: FFR was a well-tolerated, valid and reproducible tool during percutaneous intervention for TRAS. Good correlation was observed between FFR and others hemodynamic parameters of lesion severity.