Study reveals increased LVMI in renal transplant patients with functioning arteriovenous fistulas.

Kidney transplant (KT) recipients who have an asymptomatic functioning arteriovenous fistula (AVF) for hemodialysis access may be at increased risk of cardiac abnormalities, French researchers have reported.

The findings come from a study comparing 38 KT recipients with a functioning AVF and 38 without one. Luc Frimat, MD, and his colleagues at Nancy University Hospital in Nancy les Vandoeuvre, matched subjects for age, gender, and KT duration.

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Subjects had no history of CVD or diabetes, and all underwent echocardiography. Both groups had a mean age of 49 years and mean KT duration of 5.4 years. More than 85% of patients were hypertensive: 35 in the AVF group and 30 in the non-AVF group.

Left ventricular mass index (LVMI) was significantly higher in the AVF group than in the non-AVF group (135 vs. 112 g/m2), according to the paper published in Transplant International (2008; published online ahead of print). The presence of an AVF increased the risk of developing left ventricular hypertrophy fourfold. The AVF group also had higher end systole and end diastole left ventricular diameters, higher mean left atria diameter, and a higher cardiac index.

In addition, the investigators divided AVF patients into two groups based on AVF flow: a high-flow group (greater than 680 mL/min) and a low-flow group (680 mL/min or less). The high-flow group had a significantly higher cardiac index and a trend toward greater LVMI.

The authors explained that creating an AVF appears to lead to early functional cardiac adaptation to the high blood flow, as indicated by the cardiac index, left ventricular diastolic function, and late structural changes seen with a higher LVMI.

Dr. Frimat’s group cited a previous study suggesting that closing AVFs may result in LVMI regression. The study, published in the American Journal of Transplantation (2004;4:2038-2044), showed that following AVF closure, LVMI decreased from 139 g/m2 at baseline to 117 g/m2 at 21 months.

In their conclusion, the authors wrote: “While closure of the AVF may be beneficial for the patient, it can also jeopardize a valuable access that the patient would need for further hemodialysis, raising the question of whether or not the AVF access should be systematically closed after a successful KT.”