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BLOCK HF Study Biventricular versus Right Ventricular Pacing in Patients with Left Ventricular Dysfunction and Atrioventricular Block – Preliminary Results.

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Presentation on theme: "BLOCK HF Study Biventricular versus Right Ventricular Pacing in Patients with Left Ventricular Dysfunction and Atrioventricular Block – Preliminary Results."— Presentation transcript:

1 BLOCK HF Study Biventricular versus Right Ventricular Pacing in Patients with Left Ventricular Dysfunction and Atrioventricular Block – Preliminary Results Anne B. Curtis, Buffalo, NY Seth J. Worley, Lancaster, PA Philip B. Adamson, Oklahoma City, OK Eugene S. Chung, Cincinnati, Ohio Imran Niazi, Milwaukee, WI Lou Sherfesee, Minneapolis, MN Timothy S. Shinn, Ann Arbor, MI Martin St. John Sutton, Philadelphia, PA On behalf of the BLOCK HF Trial Investigators and Coordinators

2 Acknowledgments Steering Committee Curtis AB (Principal Investigator), Adamson PB, Chung ES, St. John Sutton MG, Worley SJ Echo Core Lab St. John Sutton MG, Plappert T Adverse Events Advisory Committee Boehmer JP, Meyer TE(Chair), Smith AL, De Lurgio DB Data Monitoring Committee Steinberg JS (Chair), DeMarco T, Elkayam U, Louis TA (Statistician)Investigators Canada: Rinne C, Thibault B United States: Adamson PB, Al-Sheikh T, Andriulli J, Barber MJ, Beau S, Bell M, Borgatta L, Brodine W, Canosa R, Chung ES, Compton S, Curtis AB, Ellison K, Evonich R, Faddis M, Foreman B, Murray C, Guerrero M, Herre J, Hodgkin D, Huang D, Keim S, Kocovic D, Kusmirek SL, Lessmeier T, Levanovich P, Lobban JH, Mackall JA, Manaris A, McBride W, McKenzie J, Mela T, Merliss A, Mitrani R, Mittal S, Mounsey P, Navone A, Niazi I, Obel O, Oren J, Patel P, Patel V, Pickett A, Rao A, Rist K, Rosenblum A, Saba S, Sakaguchi S, Sandler D, Sangrigoli R, Shinn TS, Simmons T, Simonson J, Smith JE, Telfer EA, Tobias S, Tomassoni G, Worley SJSponsor Medtronic Inc. Clinical Trials.gov Identifier: Clinical Trials.gov Identifier: NCT00267098 Caution: Use of CRT devices for AV block and systolic dysfunction patients without ventricular dyssynchrony is not an approved use in the United States. BLOCK HF 2

3 Background CLINICAL IMPORTANCE Over 1 million people world-wide and 819,000 people in the US have atrioventricular (AV) block Currently treated with standard pacemaker (i.e. right ventricular (RV pacing)) therapy Approximately 6 million in the US are currently diagnosed with heart failure (HF) and approximately 670,000 new cases confirmed each year According to AHA 2012 statistics, this costs the US approximately $20 to $56 billion annually DAVID and MOST Trial results have shown that RV pacing may have long-term deleterious effects Can biventricular (BiV) pacing prevent progression of heart failure and its clinical and economic consequences in AV block?Can biventricular (BiV) pacing prevent progression of heart failure and its clinical and economic consequences in AV block? BLOCK HF 3

4 Study Design Implant (CRT-P/D) Establish OMT (30-60 days) Establish OMT (30-60 days) Randomize 1:1 Control: RV pacing Treatment: BiV pacing Double- Blind Follow-up Every 3 months Follow-up Every 3 months BLOCK HF ELIGIBILITY CRITERIA AV block necessitating pacing Left ventricular ejection fraction (LVEF) < 50% NYHA functional class I, II or III Absence of a Class I indication for resynchronization therapy No previous pacemaker or implantable cardioverter defibrillator (ICD) Echocardiography performed at Randomization, 6, 12, 18 and 24 months OMT=optimal medical therapy CRT-P=cardiac resynchronization therapy pacemaker CRT-D=CRT defibrillator 4

5 Study Purpose and Objectives Purpose: Purpose: Biventricular pacing is superior to RV apical pacing in patients with AV block and LVEF <50% who require ventricular pacingEndpoints: Primary: Primary: Composite of: All-cause mortality, HF-related urgent care, defined as HF hospitalization requiring IV therapy, or Any unplanned visit requiring intravenous HF therapy, and Increase in left ventricular end systolic volume index (LVESVI) >15% Key Secondary: Key Secondary: All-cause mortality, All-cause mortality/HF hospitalization, HF hospitalization BLOCK HF 5

6 Methods Study featured: Adaptive sample size Pre-specified interim analyses Stopping rules for success, safety, futility Analysis: Analysis: Intention-to-treat Bayesian survival analysis using time to first event Parameter of interest for each endpoint: Parameter of interest for each endpoint: BiV to RV hazard ratio (HR) Metric: Metric: Probability that HR < 1 BLOCK HF EndpointStudy Success Criteria Primary Endpoint (Mortality, HF Urgent Care, LVESVI)Probability of (HR 0.9775 Secondary Endpoints All-cause Mortality All-cause Mortality/HF Hospitalization HF Hospitalization Probability of (HR 0.95 6

7 Study Flow Diagram BLOCK HF Enrollment 918 Assessed for eligibility 691 Randomized 1:1 Allocation 349 Allocated to Biventricular Pacing 346 Received allocated intervention 3 Did not receive allocated intervention 342 Allocated to Right Ventricular Pacing 342 Received allocated intervention 52 Exited/lost to follow-up 75 Deaths 13 Crossed over to Right Ventricular Pacing 3 Met primary endpoint prior to crossover 50 Exited/lost to follow-up 90 Deaths 84 Crossed over to Biventricular Pacing 50 Met primary endpoint prior to crossover 349 Analyzed 83 Censored for primary endpoint due to missing LVESVI data 342 Analyzed 71 Censored for primary endpoint due to missing LVESVI data Follow-up Analysis 227 Subjects not randomized: 95 Subjects for which AV conduction testing criteria not met prior to implant 14 Subject withdrawals prior to implant 51 Unsuccessful implants 67 Implanted subjects not randomized 7

8 BLOCK HF Follow-Up Experience BiV (N=349)RV (N=342) Average Follow-up (months)36.3 ± 23.137.9 ± 23.5 Follow-up Compliance (% of visits)94.6%93.8% 8

9 Baseline Demographics CRT-PCRT-D BiV (N=243)RV (N=241)BiV (N=106)RV (N=101) % Male75%70%82%80% Age, years74 ± 1074 ± 1172 ± 971 ± 10 LVEF, %43 ± 7 33 ± 8 Heart Rate, beats/min69 ± 2369 ± 2468 ± 1769 ± 17 QRS Duration, ms125 ± 33125 ± 31123 ± 30119 ± 30 NYHA I NYHA II NYHA III 14% 58% 27% 20% 52% 28% 10% 63% 26% 16% 57% 27% Left Bundle Branch Block35%31%35%27% Ischemic Heart Disease39%38%63%58% 1 st Degree AV Block 2 nd Degree AV Block 3 rd Degree AV Block 17% 33% 49% 15% 29% 56% 27% 33% 40% 31% 38% 32% ACE Inhibitor/ARB at Randomization71%74%83%88% Beta Blocker at Randomization75%78%92% Diuretics at Randomization64%66%72%70% BLOCK HF 9

10 Primary Endpoint Results: Mortality/HF Urgent Care/LVESVI CohortEstimated HR (95% CI)Probability HR < 1Threshold All Randomized Subjects0.74 (0.60, 0.90)0.99780.9775 CRT-P Only CRT-D Only 0.73 (0.58, 0.91) 0.75 (0.57, 1.02) BLOCK HF 10

11 Clinical Components of Primary Endpoint: Mortality/HF Urgent Care Visits CohortEstimated HR (95% CI)Probability HR < 1Threshold All Randomized Subjects0.73 (0.57, 0.92)0.997N/A CRT-P Only CRT-D Only 0.73 (0.56, 0.94) 0.73 (0.53, 1.02) BLOCK HF 11

12 Secondary Endpoint: Mortality/HF Hospitalization CohortEstimated HR (95% CI)Probability HR < 1Threshold All Randomized Subjects0.78 (0.61, 0.99)0.98020.95 CRT-P Only CRT-D Only 0.77 (0.58, 1.00) 0.80 (0.58, 1.13) BLOCK HF 12

13 Secondary Objective Results: HF Hospitalization and Mortality CohortHF HospitalizationMortalityThreshold Estimated HR (95% CI)Probability HR < 1 Estimated HR (95% CI)Probability HR < 1 All Randomized Subjects0.70 (0.52, 0.93)0.99220.83 (0.61, 1.14)0.85880.95 BLOCK HF HF HospitalizationMortality 13

14 Adverse Events Note: Table below includes pre-randomization AE’s Number of Adverse Events (N, % of Subjects) CRT-PCRT-D BiV (N=243)RV (N=241)BiV (N=106)RV (N=101) Procedure-related Complications50 (41, 17%)32 (25, 10%)18 (18, 17%)21 (16, 16%) System-related Complications* Generator-related LV lead-related 41 (36, 15%) 10 (10, 4%) 16(15, 6%) 37 (31, 13%) 11 (11, 5%) 13 (13, 5%) 48 (40, 38%) 32 (32, 30%) 6 (6, 6%) 34 (24, 24%) 13 (12, 12%) 10 (9, 9%) BLOCK HF * Subcategories for other system-related complications such as RA or RV-related complications not included 14

15 Strengths and Limitations BLOCK HF STRENGTHS:STRENGTHS: Prospective, randomized, double-blind control design Largest, longest follow-up trial to date First to show difference in outcomes in AV block and LV systolic dysfunction patients with BiV vs. RV pacing LIMITATIONS:LIMITATIONS: Long enrollment duration Censoring due to missing LVESVI in primary objective Crossover imbalance between arms: 24.6% crossed over from RV to BiV 4.6% crossed over from BiV to RV 15

16 Conclusions BLOCK HF In patients with AV block and LV systolic dysfunction (LVEF < 50%), BiV pacing compared to RV pacing leads to a significant 26% reduction in the combined endpoint of mortality, heart-failure related urgent care, and increase in LVESVI.In patients with AV block and LV systolic dysfunction (LVEF < 50%), BiV pacing compared to RV pacing leads to a significant 26% reduction in the combined endpoint of mortality, heart-failure related urgent care, and increase in LVESVI. Furthermore, there is a 27% relative risk reduction in the composite endpoint of heart-failure urgent care and all- cause mortalityFurthermore, there is a 27% relative risk reduction in the composite endpoint of heart-failure urgent care and all- cause mortality 16

17 Back-up Slides 17

18 Post-randomization Cross-overs Device GroupRV to BiVBiV to RV CRT-P60 (24.9%)9 (3.7%) CRT-D24 (23.8%)7 (6.6%) Total84 (24.6%)16 (4.6%) BLOCK HF * Percentages reflect percentage of subjects randomized subjects 18


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