Renal Denervation Reduces A-fib Recurrences in Small Study

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In addition to lowering blood pressure in patients with resistant hypertension, renal denervation may also reduce the recurrence of atrial fibrillation (A-fib), according to a small, randomized trial published online September 5, 2012, ahead of print in the Journal of the American College of Cardiology.

Researchers led by Evgeny Pokushalov, MD, PhD, of the State Research Institute of Circulation Pathology (Novosibirsk, Russia), looked at 27 patients with a history of symptomatic paroxysmal or persistent refractory A-fib and drug-resistant hypertension. Patients were randomized to catheter ablation via pulmonary vein isolation with (n = 13) or without (n = 14) bilateral renal artery denervation. For the denervation procedure, a total of 4.4 ± 0.8 RF applications of 8 to 10 watts were delivered within each renal artery, each RF ablation lasting 2 minutes.

For pulmonary vein isolation, complete disconnection of the pulmonary veins from the left atrium was successfully achieved in all 27 patients. There were no procedural complications with vein isolation or renal denervation. At 1-year follow-up, 9 of the 13 patients who received both procedures (69%) were free of A-fib compared with 4 (29%) of the patients who received pulmonary vein isolation alone (P = 0.033). In addition, all patients who received both procedures showed drops in systolic (25 ± 5 mm Hg) and diastolic (10 ± 2 mm Hg) BP that were maintained at 1 year, while patients receiving only pulmonary vein isolation showed no BP reductions (P < 0.001 vs. dual procedure group).

The pulmonary vein isolation plus denervation group also showed changes in LV dimensions and mass compared with patients who only received vein isolation (table 1).

Table 1. Mean Changes from Baseline in LV Dimensions and Mass

At 1 year, 8 of the patients with A-fib recurrences (6 with pulmonary vein isolation only, 2 with both procedures) required treatment with amiodarone. The remaining 6 patients with A-fib recurrences (4 with vein isolation only, 2 with both procedures) underwent a second procedure.

“Renal artery denervation provided incremental [A-fib] suppression after [pulmonary vein isolation] in patients with symptomatic and refractory [A-fib] in the setting of drug-resistant hypertension,” the researchers conclude.

They note that since elevated blood pressure can play a major role in developing and maintaining A-fib, renal artery ablation could optimize blood pressure, thereby acting at the substrate level of the atria to prevent the development or recurrence of A-fib.

First-in-Man Trial Raises Long-term Questions

The authors stress that the study was only a first-in-man experience of the combined therapies and that use of implantable monitors might allow more accurate detection of A-fib recurrence than office ECG and 24-hour Holter monitoring, which were used in the present study.

In an accompanying editorial, Ralph J. Verdino, MD, of the Hospital of the University of Pennsylvania (Philadelphia, PA), noted that despite the small size of the cohort, the findings were “nevertheless impressive.”

He noted that the success rates were “certainly in line with or better than published results after a single procedure without the use of antiarrhythmic drugs.”

Overall, only larger, long-term studies will answer many of the questions raised by the current findings. “Maybe with better control of hypertension, however we physiologically achieve it, we can indeed improve the success rates of catheter ablation of the atria or decrease the need to ever perform this procedure in many patients,” Dr. Verdino writes.

 

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Sources:
1. Pokushalov E, Romanov A, Corbucci G, et al. A randomized comparison of pulmonary vein isolation with versus without concomitant renal artery denervation in patients with refractory symptomatic atrial fibrillation and resistant hypertension. J Am Coll Cardiol. 2012;Epub ahead of print.

2. Verdino RJ. Catheter ablation for the treatment of atrial fibrillation: Have we been targeting the wrong organ? J Am Coll Cardiol. 2012;Epub ahead of print.

 

 

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