A systematic review and meta-analysis of cardiac resynchronization therapy in inotrope-dependent heart failure: an update
Authors: Al-Shakarchi N , Ho J S Y , Bray J J H , D'ascenzo F , Duffy E , Hewett J , Adegbie D , Khan F , Kumar N S , Patel N , Haq I , Ahmed M 
Published: November 2023

Abstract

Background
Inotrope-dependent heart failure (HF) carries a poor prognosis. Advanced mechanical supports have been viewed as primary treatment modalities for these patients, but cardiac resynchronization therapy (CRT) is an emerging alternative. Whether CRT is viable in HF patients who require inotropic support is uncertain.

Purpose
To assess outcomes of CRT in end-stage inotrope-dependent HF.

Methods
Following PRISMA guidelines, we searched Medline, EMBASE, Scopus, and Cochrane Library until December 31st 2022, with the following terms: "end-stage heart failure," "catecholamine-dependent overt heart failure," "inotrope-dependent heart failure," "advanced heart failure," "New York Heart Association class IV," "NYHA class IV." These terms were combined with "cardiac resynchronization therapy" OR "CRT" OR "biventricular device". Studies were included if: 1) HF patients required on inotropic support at CRT implantation; 2) patients were at least 18 years old; and 3) provided a clear definition of "inotrope dependence" or "inability to wean." A meta-analysis with random effects was performed in R (Version 3.5.1) with data presented as mean ± standard error.

Results
19 studies comprised of 386 inotrope-dependent HF patients (mean age 64.4 ± 1.2 years, 76.9% male, 54.6% non-ischemic cardiomyopathy, mean QRS duration 168.0 ± 4.6 ms, mean follow-up 778 ± 110.7 days) were included for meta-analysis. A large majority of patients survived until discharge at 90% (95% CI: 81.0%-96.8%, I2=51%, p=0.04, Figure 1A), 88.6% were weaned off inotropes (95% CI: 77.5%-96.8%, I2=64%, p&lt;0.01), and mean time to discharge post-CRT was 7.8 days (95% CI: 3.9-11.7, I2= 84%, p&lt;0.01). After one year of follow-up 69.5% survived (95% CI: 59.2%-78.9%, I2=53%, p=0.02, Figure 1B) and 59.1% (95% CI: 50.1%-67.8%, I2=58%, p&lt;0.01, Figure 1C) were alive at the end of follow-up. During follow-up the mean number of hospital admission for HF was reduced by 1.87 (95% CI: 2.70-1.04, I2=77%, p=0.04). Post-CRT mean QRS duration was reduced by 29.0 ms (95% CI: 41.33-16.68, I2=69%, p=0.006, Fig) and mean left ventricular ejection fraction increased by 4.83% (95% CI: 3.09%-6.57%, I2=16%, p=0.31, Fig). The mean NYHA class post-CRT was 2.7 (95% CI: 2.5-3.0, I2=56%, p=0.03, Figure 2A), 39.6% (95% CI: 18,.7%-62.3%, I2=83%, p&lt;0.01, Figure 2C) improved to NYHA class III and 34.6% (95% CI: 16.4%-55.2%, I2=79%, p&lt;0.01, Figure 2D) improved to NYHA class II. Responders to CRT tended be male (85.7% vs. 40%, p=0.015), have a history of left bundle branch block (71.4% vs. 30%, p=0.036) or an increased left ventricular end-diastolic volume (274.3 mL vs. 225.9 mL, p=0.038).

Conclusion(s)
Our results suggest that CRT is an alternative option for end-stage inotrope-dependent HF, improving survival, NYHA status, and HF readmission. CRT responders appear to be male with evidence of preserved diastolic function or a history of a left bundle branch block.