A prospective non-randomized open label multi-center study to evaluate the effect of an iliofemoral arteriovenous fistula on blood pressure in patients with therapy-resistant hypertension

The creation of a calibrated iliofemoral arteriovenous fistula (IAVF) increases exercise capacity in patients with severe COPD. In a retrospective analysis of 24 subjects with end-stage COPD and hypertension IAVF decreased systolic office blood pressure (BP) significantly at 12 months by an average of -12.8 mmHg. We assessed the effect of IAVF on BP and echocardiographic changes in therapy-resistant hypertensive patients. In 8 patients with therapy-resistant hypertension an IAVF was created using the ROX Anastomotic Coupler System®. The study evaluated safety and efficacy. Ambulatory (ABPM), office (OBPM) and home blood pressure measurement (HBPM), heart rate (HR), ECG, and renal function were monitored at 0, 1, 3 and 6 months. A repeated measures anova, adjusted for multiple comparisons (least significant difference) was used to analyze the data. Echocardiography was performed pre- and 6 month post-procedure (analyzed with paired t-test). Data are presented as means ± SE. 5 males and 3 females were on an average of 4.0±0.8 different antihypertensive drugs. Systolic OBPM dropped from 175.3±6.8 to 162.8±8.5 mmHg after 3 months, and to 160.3±9.0 after 6 months while diastolic OBPM dropped from 87.3±5.1 to 75.5±5.7 mmHg and to 71.7±5.7, respectively. Decrease was statistically significant over time with a p-value of 0.027 for systolic BP and 0.005 for the diastolic BP. Systolic ABPM decreased from 151.9±5.9 to 146.3±7.3 mmHg after 3 months, and to 145.5±5.7 after 6 months. Diastolic ABPM decreased from 82.0±5.4 to 72.0±5.5 mmHg and 68.5±4.7, respectively. HR, ECG and renal function did not alter. Echocardiographical analysis in the Belgian center (n=5) showed a significant increase in E/A ratio (0.48±0.17 (p=0.047)) and E' (0.02±0.01 m/sec (p=0.035)); E/E', deceleration time and isovolumic relaxation time decreased; interventricular septal thickness at diastole (IVSd) decreased significantly (-0.290±0.056 (p=0.007)). One patient developed mild lower leg edema; no other adverse events were seen. In this prospective study in 8 patients with therapy-resistant hypertension the creation of an iliofemoral AVF decreased ABPM and OBPM after 1, 3 and 6 months. In a small group, the echocardiographical changes are suggestive for an evolution from type II pseudonormal mitral flow (hypertension as cause of diastolic dysfunction) to type I flow. The procedure has proven safety in larger studies in COPD patients. Further exploration of this technique as a possible new approach for treating pharmacotherapy resistant hypertensive patients is warranted in a larger randomized trial.