BARCELONA, Spain — Multipoint pacing (MPP) did not show an overall advantage over conventional biventricular (BiV) pacing in patients unresponsive to cardiac resynchronization therapy (CRT), but programming patterns appear to play a role in who might benefit.
The percentage of patients who converted from nonresponse to echocardiographic response 12 months after enrollment was 31.8% with MPP and 33.8% with BiV pacing (P = .65).
MPP programming, however, was left to the physician’s discretion, and less than a third of patients received optimal MPP programing, which on the basis of results of the recent MPP IDE Clinical Study uses the widest anatomic electrode separation (at least 30 mm) and shortest timing delays of 5 milliseconds.
In an exploratory analysis, the conversion rate increased to 45.6% among 68 patients who received this MPP-anatomic separation programming and 26.2% among 168 patients programmed with other MPP settings (P = .006).
There was a nonsignificant trend between MPP-anatomic separation programming and BiV pacing (P = .102), study chair Christophe Leclercq, MD, CHU de Rennes, Frances, said during the late-breaking trial session here at the European Heart Rhythm Association (EHRA) 2018 congress.
Although “indiscriminate multipoint pacing” did not show any advantage on left ventricular (LV) remodeling compared with biventricular pacing, “pacing the left ventricle simultaneously with a delay of 5 milliseconds with the largest possible LV bipole, more than 30 millimeters, might be beneficial,” he said.
Phase 2 of the trial, in which MPP-anatomic separation programming is mandatory in patients randomly assigned to MPP, is due to be completed in March 2019.
Leclercq observed that CRT can produce significant clinical benefits but that 40% to 50% of patients implanted with a CRT device are nonresponders based on LV reverse remodeling. The investigators hypothesized that using a larger LV pacing vector with multipoint pacing could help transform echocardiographic nonresponders to conventional BiV pacing into responders. MPP programming has shown positive results in the recent MPP IDE and IRON-MPP studies.
For phase 1 of the More Response on Cardiac Resynchronization Therapy with MultiPoint Pacing (MORE-CRT MPP) study, 1921 patients receiving a quadripolar CRT system were prospectively enrolled and followed for 6 months. Patients with less than a 15% reduction in LV end systolic volume at 6 months were classified as nonresponders and randomly assigned to another 6 months of MPP (n = 236) or to BiV pacing (n = 231).
At enrollment, the mean age of the patients (80% male) was 68 years, mean LV ejection fraction was 26%, and mean LV end systolic volume was 163 mL.
Overall, 46.7% of patients were NYHA class II and 50.5% were class III at enrollment, improving after 6 months of pacing (at the time of randomization) to NYHA class I in 16.8%, class II in 64.9%, and class III in 17.9%, Leclercq said. Two thirds of patients (66.8%) had left bundle branch block (LBBB), as analyzed by a core lab.
In subgroup analysis, there was no significant difference in the primary endpoint between MPP and BiV pacing based on presence or absence of LBBB, ischemic or nonischemic etiology, QRS duration, or NYHA class.
When the investigators looked at the predefined subgroups in the exploratory analysis, however, patients with NYHA class III or IV appeared to fare better with MPP-anatomic separation programming than with BiV pacing (odds ratio, 2.39; 95% CI, 1.16 – 4.89; P = .018), he said.
Discussant Cecilia Linde, MD, PhD, Karolinska University Hospital, Stockholm, Sweden, noted that reverse remodeling is an important part of response to CRT but is not the only mechanism of action.
One of the challenges in interpreting the phase 1 data rests in the definition of nonresponder “because you cannot isolate it to reverse remodeling, especially in the group of patients with ischemia who do not have the same propensity to reverse their left ventricular dimensions but still derive at least as great a benefit regarding mortality and morbidity,” she said.
The study also provides little information on where in the coronary sinuses the LV lead was placed, how core lab echo evaluation was done, and the method used to program MPP to its full potential.
“Were we in fact comparing BiV pacing to BiV pacing or MPP to BiV?” Linde asked provocatively.
She continued, “So my conclusion is that from this part of the study, the phase 1, we can draw no firm conclusion about the value of MPP programming. But there is another phase to come, and hopefully that will reveal perhaps a little bit more of a benefit or at least will give us an answer on the value of this trial.”
The study was sponsored by Abbott. Leclercq reported research grants from Abbott, Boston Scientific, Livanova, and Medtronic; serving as a consultant or advisory board member for Abbott, Boston Scientific, Biotronik, Medtronic, and Livanova; and lecturing for Abbott, Bayer, Boehringer, Boston Scientific, Biotronic, Medtronic, and Livanova.
European Heart Rhythm Association (EHRA) 2018. Presentation 954. Presented March 20, 2018.
Follow Patrice Wendling on Twitter: @pwendl. For more from theheart.org | Medscape Cardiology, follow us on Twitter and Facebook.
Tidak ada komentar:
Posting Komentar