Impact of isometric handgrip exercises on cephalic vein diameter in non-AVF candidates, a pilot study.

Purpose: Incident arteriovenous fistula (AVF) rates remain low. AVF placement is often not attempted because of small cephalic vein (CV) diameter. We postulated that isometric handgrip exercises would increase forearm CV diameter and allow successful AVF creation in non-AVF candidates. Methods: Adult subjects without prior vascular access (eGFR<25mL/min/1.73m(2); CV<2.5mm) were prospectively enrolled. They performed daily handgrip exercises in the preferred access arm (EA), with the nonexercised arm (NEA) as control. Adherence was assessed by exercise logs and grip strength. CV diameter was measured at baseline, four and eight weeks by ultrasound. The primary endpoint was the mean increase in CV diameter. Secondary endpoints were mean CV diameter increase from baseline, increased proportion of potential AVF sites and successful AVF placement. Results: A total of 17 subjects were enrolled and 15 completed the study. EA grip strength increased significantly. Mean CV diameter increased in both the EA and NEA by 0.48-0.59 and 0.71-0.81mm (P=NS), respectively. Compared to baseline, all CV diameters increased significantly (P<.05) after four weeks. In the EA, mean distal and proximal CV increased from 1.66 to 2.13 mm and from 2.22 to 2.81 mm, respectively. Similar changes were noted in the NEA. There were also significant increases in the number of sites and subjects eligible for AVF creation. Five subjects had successful AVF placement. Conclusions: Isometric handgrip exercises resulted in significant CV diameter increases after four weeks, in both the EA and the NEA and potentially allows for AVF creation in those not previously deemed candidates.