Fewer CRT-Lead-Related Complications With Quadripolar Vs Bipolar Leads: MORE CRT Trial

September 12, 2014

BARCELONA, SPAIN — Current growth in the use of quadripolar leads instead of bipolar leads with biventricular pacemakers could potentially lead to safer and more uneventful implantation procedures, suggests a rare randomized, controlled study of pacemaker leads in heart failure.

In the trial of more than 1000 patients, those in whom quadripolar leads were used, compared with patients getting traditional bipolar leads, showed a 41% drop in risk of lead-related complications (p=0.0001), especially those afflicting the implantation procedure such as phrenic-nerve stimulation or lead instability.

The More Options Available with a Quadripolar LV Lead Provide In-Clinic Solutions to CRT Challenges (MORE-CRT) trial, sponsored by St Jude Medical, used the company's quadripolar leads. A third of the bipolar leads came from St Jude and the rest from Medtronic, Boston Scientific, Biotronik, and Sorin, said Prof Giuseppe Boriani (University of Bologna, Italy) here last week when presenting MORE-CRT at the European Society of Cardiology (ESC) 2014 Congress . Those other companies also market quadripolar leads for cardiac resynchronization therapy (CRT) systems.

Boriani, who chairs the MORE-CRT steering committee, told heartwire that having four vs two electrodes "improves the efficiency" of the insertion procedure by making it easier for the operator to position the leads, "manage common pacing complications," and "capture the left ventricle." Those advantages, he said, seem to make intraprocedural lead complications less likely, potentially preventing some second procedures to correct lead problems.

There was no six-month mortality difference between the groups getting the two types of lead, although the trial wasn't powered for clinical end points, pointed out Dr John GF Cleland (Harefield Hospital and Imperial College London, UK) as assigned discussant following Boriani's presentation of the trial. But it was of interest, he said, that mortality in both groups was very similar to that in the Cardiac Resynchronization-Heart Failure (CARE-HF) trial almost a decade ago. (Cleland was CARE-HF principal investigator.)

Based on the trial, he said, "Quadripolar catheters are safe and improve the doctor and patient implant experience, probably substantially in 10% of cases, and more subtly in a larger number of subjects. There's no substantial improvement in [the rate of successful CRT implantation procedures] observed in this study or outcomes at six months in these unselected patients, but perhaps if we target those less likely to respond [well to bipolar leads], there might be an advantage to the quadripolar lead."

MORE CRT randomized 1068 patients undergoing CRT procedures in 13 countries to receive quadripolar (n=720) or bipolar (n=348) leads. The former group was significantly more likely to be free of a composite primary end point reflecting both intra- and postoperative left-ventricular lead-related complications, for a relative-risk reduction of 40.8%.

In analyses of intra- and postoperative lead complications separately, the reduction in the primary end point was seen to be driven primarily by an improvement in intraoperative events, a 56.4% relative-risk reduction.

End points All Patients Bipolar Leads Quadripolar Leads p, Bipolar Vs Quadripolar
Intra- or postoperative lead-related events* 16.1 22.3 13.2 0.0002
Intraoperative events 8.5 13.7 6.0 <0.0001
Postoperative events 8.6 10.4 7.8 0.178
*Primary end point: combined intra- and postoperative LV lead-related events. Intraoperative events included those due to phrenic-nerve stimulation, lead instability, or high capture threshold leading to change in tributary vein of coronary sinus after target-site evaluation, use of more than one LV lead during the procedure for any reason, use of any device (such as stent) to actively fixate the lead, or unsuccessful implantation for any reason. Postoperative events could be any serious adverse device effect related to the LV lead or abandonment of CRT for any reason.

Cleland noted that cost-effectiveness wasn't included in the MORE CRT analysis. "I have to say that the cost of a quadripolar lead is somewhere between three and four times the cost of a bipolar lead, and this needs to be taken into account. . . . I think it's quite reasonable based on MORE CRT that cardiologists should choose what they prefer provided the extra cost would not be spent on something of greater value," he said.

"American cardiologists are already preferring quadripolar leads to the bipolar leads, so there is already a large move toward the use of quadripolar leads. I think it is to some extent becoming the standard of care before the randomized, controlled trial evidence is available. And therefore it's welcome that we're seeing this first trial."

MORE-CRT was sponsored by St Jude Medical. Boriani discloses fees for speaking from St Jude Medical, Medtronic, Boston Scientific, and Boehringer Ingelheim.


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