MORE-CRT: Quadripolar leads reduced risk for complications

BARCELONA, Spain — A quadripolar left ventricular lead for a cardiac resynchronization therapy device was associated with a reduction in risk for lead-related complication compared with bipolar leads, according to results of the MORE-CRT study.

Giuseppe Boriani, MD, PhD, FESC, from Policlinico Universitario S. Orsola-Malpighi, University of Bologna, Italy, and colleagues hypothesized that using a quadripolar LV lead (Quartet, St. Jude Medical) would result in easier CRT implantation procedures and a lower rate of lead-related complications compared with standard LV bipolar leads. Boriani presented the results at ESC Congress.

They conducted the MORE-CRT study of 1,068 patients with HF from 63 centers across 13 countries between November 2011 and August 2013. Participants were randomly assigned to the quadripolar CRT system implant (n=720) or a bipolar CRT system implant; some made by St. Jude Medical and some not (n=348). The primary outcome was a composite endpoint of intra- and postoperative LV lead-related complications.

Freedom from complications

At 6 months, those receiving the quadripolar leads were more likely to be free from the composite outcome compared with controls (85.97% vs. 76.86%; P=.0001) with a relative risk reduction of 40.8%, Boriani and colleagues found.

Boriani said at a press conference that the results were driven by differences in the incidence of intraoperative complications (5.98% vs. 13.73%; RR reduction=56.4%; P<.0001).

The quadripolar lead “provides more options to effectively manage common pacing complications, as compared to systems based on bipolar leads; hence, improving the efficiency of CRT,” Boriani said in a press release.

Challenges addressed

George H. Crossley

Quadripolar technology addresses two major challenges of CRT, George H. Crossley, MD, FHRS, FACC, associate professor at Vanderbilt Heart and Vascular Institute in Nashville, Tenn., said in an interview with Cardiology Today.

First is “the avoidance of the phrenic nerve that lies right along the part of the heart where we typically put a wire for [CRT],” he said. “We’re pretty good at avoiding it, but as the patient’s posture changes … the association of that nerve and the heart changes. And so, in most studies of CRT, there’s a 4% to 5% chance, sometimes as much as 8%, that you’ll have problems with pacing the phrenic nerve.”

Second, by having four electrodes, quadripolar technology “gives us a number of vectors to choose from in pacing,” Crossley said. “We can choose the one that gives the best results for increasing the squeeze of the heart. We increase the chance of success from a HF standpoint and we decrease the chances of a complication.”

Results of a trial of Medtronic’s quadripolar technology will be presented at the American Heart Association Scientific Sessions in November, Crossley said. – by Erik Swain

For more information:

Boriani G. Hot Line I. Cardiovascular Disease: Novel Therapies. Presented at: the European Society of Cardiology Congress; Aug. 30-Sept. 3, 2014; Barcelona, Spain.

Disclosure: The study was funded by St. Jude Medical. Boriani reports speaking for Boehringer Ingelheim, Boston Scientific, Medtronic and St. Jude Medical. Crossley reports serving on advisory boards of and receiving research funding from Boston Scientific and Medtronic.

George H. Crossley, MD, FHRS, FACC, can be reached at: Vanderbilt Heart and Vascular Institute, Suite 5209, 1512 21st Ave. South, Nashville, TN 37232-8802; email: george.crossley@vanderbilt.edu.