Remote Ischemic Preconditioning for Renal Protection in Patients Undergoing Transcatheter Aortic Valve Interventions

Background
Severe aortic stenosis remains a major source of morbidity and mortality of the elderly with an estimated nearly 27,000 patients becoming candidates for transcatheter aortic valve interventions (TAVI) annually. Pre-procedural CT scans are routinely performed for planning. Despite use of pre-hydration strategies, contrast induced nephropathy (CIN) remains a major source of concern particularly in this aging population with baseline renal dysfunction. We sought to evaluate the effects of remote ischemic preconditioning (RIPc) on prevention of CIN post TAVI.

Methods
Single center, randomized controlled trial enrolling 46 patients from February 2018 to October 2018. Selected patients had an estimated glomerular filtration rate (eGFR) less than 60ml/min indicating advanced chronic kidney disease stage 3 based on the modified diet in renal disease (MDRD) equation. Following procedural sedation RIPc was initiated and completed prior to valve implantation. The control group received the sham with manual blood pressure cuff inflations to 40 mmHg for 5 minutes, followed by 5 minutes of reperfusion for a total of 4 cycles. The intervention group received manual blood pressure cuff inflations to 200 mmHg for 5 minutes, followed by 5 minutes of reperfusion for a total of 4 cycles. Labs were ordered for 48-72 hours post procedure. CIN was defined as a serum rise in creatinine (Cr) of 0.5mg/dl or a 25% relative rise in Cr 48-72 hours after contrast exposure.

Results
Of the 46 patients enrolled, 26 were randomized to the intervention group and 20 to the control group. The average age of study participants was 80. In the intervention group, the average eGFR was 43 ml/min, average Cr was 1.39 mg/dl, and average contrast load was 120mL. In the control group, the average eGFR was 41 ml/min, average Cr was 1.49mg/dl, and average contrast was load 99ml. One patient developed CIN in the intervention group however, they did not require renal replacement therapy. Otherwise, there was no change or a decrease in measured Cr post intervention.

Conclusions
This study was designed as a pilot study to evaluate the effects of RIPc on renal function post TAVI. In this study, there was no trend towards benefit and no signals towards harm however, a larger sample size is needed.