EnligHTN I Published: Renal Denervation with Multielectrode Catheter Safe, Effective

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Renal sympathetic denervation using a novel multielectrode device rapidly reduces office blood pressure (BP), an improvement that is sustained through 6 months, according to data from the EnligHTN 1 trial published online June 19, 2013, ahead of print in the European Heart Journal.

The findings were previously presented at the 2012 American Heart Association Scientific Sessions in Los Angeles, CA.

For the EnligHTN I trial, Stephen G. Worthley, MBBS, PhD, of Royal Adelaide Hospital (Adelaide, Australia), and colleagues enrolled 46 patients who had resistant hypertension despite taking 4.1 ± 0.57 different classes of antihypertensive medications concurrently at maximum tolerated doses. Renal denervation was performed using the EnligHTN multielectrode catheter ablation system (St. Jude Medical, St. Paul, MN).

According to the paper, “the single electrode [radiofrequency] catheter system that has been widely used for this technique has the disadvantage of requiring the operator to manipulate the catheter within the renal artery lumen multiple times to achieve a series of lesions,” whereas the newer device reduces the need for such manipulation and potentially decreases the risk of procedure-related arterial injury.

Both Office, Ambulatory BP Lowered 

At baseline, patients had a mean office BP of 176/96 mm Hg and mean 24-hour ambulatory BP of 150/83 mm Hg.

Treatment resulted in sustained decreases in office BP at 6 months (primary endpoint) as well as reduced ambulatory BP over the same time span (P < 0.001 for both vs. baseline; table 1).

Table 1. Mean Changes in BP, mm Hg

 

1 Month

3 Months

6 Months

Office
Systolic
Diastolic

 
-28
-10

 
-27
-10

 
-26
-10

Ambulatory
Systolic
Diastolic

 
-10
-5

 
-10
-5

 
-10
-6


These gains were achieved with few modifications to patients’ antihypertensive drug regimens. Over 6-month follow-up, 13% of patients decreased and 8.7% increased such medications. As many as 80% of patients obtained reductions in office systolic BP of 10 mm Hg or greater during follow-up, with up to 41% showing an office BP of less than 140 mm Hg. Baseline systolic BP strongly predicted response (P < 0.0001).

No acute renal artery injury or other serious vascular complications were observed. Serious adverse events included 1 instance (2%) each of hypertensive renal disease progression (at 93 days), hypotension (at 137 days), and progression of preexisting renal artery stenosis (at 169 days). Minor periprocedural events related to the device or procedure included non-flow limiting vasospasms (15%), vascular access site hematomas (17%), hypotension (7%), vasovagal episodes (4%), bradycardia (4%), transient hematuria (4%), pain (2%), and nausea (2%).

Changes in estimated glomerular filtration rate, described as non-clinically relevant at less than 6%, occurred between baseline (87 ± 19 mL/min/1.73 m2) and 6 months (82 ± 20 mL/min/1.73 m2).

Effect Seen Earlier with Newer Device

Dr. Worthley and colleagues note that the overall reductions in office BP compare well with previously published results of the single-electrode Symplicity catheter (Medtronic, Minneapolis, MN).

“Of interest, reductions in BP were recorded earlier in the current study [-28/-10 mm Hg by 1 month], whereas previous studies found that while BP was reduced at 1 month, a comparable reduction was not seen until 6 months. Arguably, the more rapid response seen in the current study may reflect more complete renal denervation acutely due to the use of a multielectrode [radiofrequency] catheter system compared with a single electrode system,” they write, acknowledging that random chance may also be responsible.

Based on the current findings, “the EnligHTN multielectrode system delivers a promising therapy for the treatment of drug-resistant [hypertension],” the investigators conclude.

 


Source:
Worthley SG, Tsioufis CP, Worthley MI, et al. Safety and efficacy of a multi-electrode renal sympathetic denervation system in resistant hypertension: The EnligHTN I trial. Eur Heart J. 2013;Epub ahead of print.

 

 

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Disclosures
  • The study was funded by St. Jude Medical.
  • Dr. Worthley reports receiving modest research grant and honoraria from Medtronic and St. Jude Medical.

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