Cecilia Linde1, Anne B Curtis2, Gregg C Fonarow3, Kerry Lee4, William Little5, Anthony Tang6, Francisco Levya7, Shin-ichi Momomura8, Christopher Manrodt9, Tracy Bergemann9, Martin R Cowie10. 1. Karolinska University Hospital, Stockholm, Sweden. Electronic address: cecilia.linde@ki.se. 2. University at Buffalo, Buffalo, NY, USA. 3. University of California, Los Angeles, USA. 4. Duke Clinical Research Institute, Durham, NC, United States. 5. Wake Forest University, United States. 6. University of Western Ontario, Canada. 7. Birmingham, United Kingdom. 8. Jichi Medical University Saitama Medical Center, Saitama, Japan. 9. Medtronic Inc., Minneapolis, MN, USA. 10. Imperial College London, The Royal Brompton Hospital, London, United Kingdom.
Abstract
BACKGROUND: The benefits of CRT for symptomatic heart failure (HF) patients with a wide QRS and reduced left ventricular ejection fraction (LVEF≤35%), are well established .Post-hoc subgroup analyses suggest that CRT benefit may extend to patients with LVEF>35%. METHODS: The MIRACLE EF was a prospective, randomized, controlled, double-blinded study to evaluate CRT-P in NYHA II-III HF patients with LBBB and with LVEF of 36%-50% and no previous pacing or ICD. The primary endpoint was a composite of time to first HF event or death. All patients were implanted with a CRT-P and randomized 2:1 to CRT-P ON or CRT-P OFF groups. The minimum follow up time was 24 months. RESULTS: The MIRACLE EF study was stopped for enrollment futility after 13 months and enrolling only 44 patients. The main difficulties in recruiting patients were lack of eligible patients, previous ICD implants, and the reluctance of institutions, patients or physicians to enroll in the study which included a potential 5 year CRT OFF period. CONCLUSION: Despite a careful design, identification and randomization of eligible patients were challenging and a trial to assess morbidity and mortality trial was not feasible. The MIRACLE EF experience illustrates the difficulties of designing a scientifically robust but feasible study to assess potential new indications for implantable devices. Smaller randomized studies with surrogate endpoints may therefore be more reasonable, although the potential impact of such studies on clinical practice, guidelines, and reimbursement remain to be determined.
RCT Entities:
BACKGROUND: The benefits of CRT for symptomatic heart failure (HF) patients with a wide QRS and reduced left ventricular ejection fraction (LVEF≤35%), are well established .Post-hoc subgroup analyses suggest that CRT benefit may extend to patients with LVEF>35%. METHODS: The MIRACLE EF was a prospective, randomized, controlled, double-blinded study to evaluate CRT-P in NYHA II-III HF patients with LBBB and with LVEF of 36%-50% and no previous pacing or ICD. The primary endpoint was a composite of time to first HF event or death. All patients were implanted with a CRT-P and randomized 2:1 to CRT-P ON or CRT-P OFF groups. The minimum follow up time was 24 months. RESULTS: The MIRACLE EF study was stopped for enrollment futility after 13 months and enrolling only 44 patients. The main difficulties in recruiting patients were lack of eligible patients, previous ICD implants, and the reluctance of institutions, patients or physicians to enroll in the study which included a potential 5 year CRT OFF period. CONCLUSION: Despite a careful design, identification and randomization of eligible patients were challenging and a trial to assess morbidity and mortality trial was not feasible. The MIRACLE EF experience illustrates the difficulties of designing a scientifically robust but feasible study to assess potential new indications for implantable devices. Smaller randomized studies with surrogate endpoints may therefore be more reasonable, although the potential impact of such studies on clinical practice, guidelines, and reimbursement remain to be determined.
Authors: Nathaniel Katz; Robert H Dworkin; Richard North; Simon Thomson; Sam Eldabe; Salim M Hayek; Brian H Kopell; John Markman; Ali Rezai; Rod S Taylor; Dennis C Turk; Eric Buchser; Howard Fields; Gregory Fiore; McKenzie Ferguson; Jennifer Gewandter; Chris Hilker; Roshini Jain; Angela Leitner; John Loeser; Ewan McNicol; Turo Nurmikko; Jane Shipley; Rahul Singh; Andrea Trescot; Robert van Dongen; Lalit Venkatesan Journal: Pain Date: 2021-07-01 Impact factor: 6.961