Renal Artery and Atrial Ablation for Resistant Hypertension and Atrial Fibrillation

Abstract & Commentary

By John P. DiMarco, MD, PhD, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville. Dr. DiMarco does research for Medtronic, is a consultant for Medtronic, Novartis, and st. Jude, and is a speaker for Boston scientific.

Source: Pokushalov E, 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;60:1163-1170.

This paper reports the early results from a “proof-of-concept” study looking at combined renal artery denervation and pulmonary vein isolation in hypertensive patients with atrial fibrillation. The authors randomized patients with drug refractory atrial fibrillation and drug-resistant hypertension to either standard pulmonary vein isolation or pulmonary vein isolation with renal artery denervation in a single procedure. Patients were screened with magnetic resonance imaging before the study. Patients with renal artery stenosis or dual renal arteries, advanced congestive heart failure, markedly enlarged left atria, prior atrial fibrillation ablation, or treatment with amiodarone were excluded. All patients underwent pulmonary vein isolation using standard techniques. Right atrial ablation lesions were also placed in patients with a history of typical atrial flutter. Renal artery denervation was performed during the same procedure. The aortorenal artery system was mapped using the same three-dimensional navigation system and catheter that had been used for the pulmonary vein isolation. Radiofrequency lesions were applied between the first distal main artery all the way back to the renal artery origin. Up to six lesions were performed within each renal artery. High-frequency stimulation before and after each radiofrequency delivery was used to assess response.

After the procedure, all patients had a 3-month blanking period during which they were treated with propafenone or flecainide. After that, antiarrhythmic drugs were discontinued. Weekly electrocardiograms were obtained for the first month and 24-hour Holter recordings were performed at 3, 6, 9, and 12 months after the procedure. Renal function at 6 months was assessed by magnetic resonance angiography and glomerular filtration measurement. The primary endpoint of the study was documentation of more than 30 seconds of atrial tachyarrhythmia after a single ablation procedure.

This preliminary study enrolled 27 patients, with 14 randomized to pulmonary vein isolation only and 13 randomized to the combined procedure. The mean age in both groups was 56 years and most patients were male. Complete disconnection of the pulmonary veins was successfully achieved in all 27 patients. All patients randomized to renal denervation had successful elimination of any hypertensive response to high-frequency stimulation during the procedure. Pulmonary vein isolation plus renal denervation took approximately 40 minutes longer than the standard procedure, with an additional mean increase of 8 minutes of fluoroscopy time. There were no procedure-related complications either during the procedure or detected at their 6-month follow-up imaging. The patients who had the combined procedure had a 31% 1-year recurrence rate in contrast to a 71% recurrence rate in the patients who underwent pulmonary vein isolation only. Four patients in the pulmonary vein isolation only group and two patients in the combined procedure group underwent a second procedure. Renal artery denervation resulted in improved blood pressure control with documented reduction in both systolic and diastolic blood pressures, and follow-up echocardiography left ventricular mass was also reduced.

The authors concluded that renal artery denervation added to pulmonary vein isolation helps suppress atrial fibrillation in patients with drug-resistant hypertension.

Commentary

Patients with advanced, severe, drug-resistant hypertension often have atrial fibrillation. Pulmonary vein isolation procedures in these patients have had disappointing results, presumably because they have advanced electrical remodeling of the left atrium in the setting of the chronic hypertensive stress. Recently, renal artery denervation has been introduced as an alternative therapy in patients with drug-resistant hypertension. This paper is the first to show that a combined procedure that treats both the triggers for atrial fibrillation and the hypertension which continues to alter the left atrial substrate may be an effective approach.

This is only a small group of patients and the recurrence rate even in the combined procedure group is still quite high. However, this is the first demonstration in a randomized trial that the combined procedure may be more effective and may offer these very resistant patients a better chance at returning to sinus rhythm. We can look forward to future, more definitive studies investigating this concept.