Supervised preoperative forearm exercise to increase blood vessel diameter in patients requiring an arteriovenous access for hemodialysis: rationale and design of the PINCH trial.

BACKGROUND: Failure of maturation occurs in 30%-60% of arteriovenous fistula (AVF) creation for hemodialysis, with highest rates in distal radiocephalic fistulas. This is partly due to initial small blood vessel size with limited blood flow capacity. Forearm exercise has shown potential as stimulus for increasing blood vessel size in patients with end-stage renal disease (ESRD) and may promote maturation of AVFs in the upper limb when applied postoperatively. However, it is unknown if forearm exercise increases blood vessel size pre-operatively, which may contribute to more distal AVF creation and raise success rates of AVF surgery. This study will investigate these issues.

METHODS AND RESULTS: The PINCH trial (refers to 'pinching') is an investigator-initiated, multicenter, single-blinded, randomized controlled trial with 1:1 randomization to perform supervised forearm exercises compared to no exercise 6 weeks pre-operatively before creation of an AVF. Forty patients receiving an AVF will be included. The main study endpoints are blood vessel diameter (cephalic or basilic vein and radial and ulnar artery), AVF surgical plan (radiocephalic or brachiobasilic/cephalic), and three-month (assisted) maturation rate. The burden of the performed forearm exercises will be evaluated using Kidney Disease Quality of Life (KDQOL-SF Dutch version 1.2) and exercise specific questionnaires. The PINCH trial is planned to start in November 2017. Enrollment is expected to be completed at the end of 2019.

CONCLUSIONS: The PINCH study is the first trial to evaluate the effect of pre-operative, supervised forearm exercises on vein diameter and fistula maturation in hemodialysis patients.

TRIAL REGISTRATION: NTR6382.