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Risk Stratification in Nonischemic Dilated Cardiomyopathy Using CMR
Quick Takes
- Both presence and extent of LGE were associated with all-cause mortality, CV mortality, arrhythmia, HF events, and MACE in patients with nonischemic dilated cardiomyopathy (NIDCM).
- Of note, higher LVEF was associated with lower risk for HF events and MACE, but had no significant association with all-cause mortality, CV mortality, and arrhythmic risk.
- Enhanced risk stratification and refined selection of ICD candidates through CMR imaging may avert considerable costs related to unnecessary ICD implantations and subsequent lifetime management, while allowing life-saving treatment for SCD-prone patients with NIDCM not captured by current selection criteria.
Study Questions:
What is the association of cardiac magnetic resonance (CMR) imaging–derived measurements with clinical outcomes in nonischemic dilated cardiomyopathy (NIDCM)?
Methods:
The investigators systematically searched MEDLINE, Embase, Cochrane Library, and Web of Science Core Collection databases for articles from January 2005 to April 2023. Prospective and retrospective nonrandomized diagnostic studies reporting on the association between CMR imaging–derived measurements and adverse clinical outcomes in NIDCM were deemed eligible. Prespecified items related to patient population, CMR imaging measurements, and clinical outcomes were extracted at the study level by two independent reviewers. Random-effects models were fitted using restricted maximum likelihood estimation and the method of Hartung, Knapp, Sidik, and Jonkman. All-cause mortality, cardiovascular (CV) mortality, arrhythmic events, heart failure (HF) events, and major adverse cardiac events (MACE) were the main outcome measures. To explore the impact of study and patient characteristics on associations of CMR imaging–derived measurements with clinical outcomes, random-effects meta-regression was performed for those endpoints with ≥10 studies available.
Results:
A total of 103 studies including 29,687 patients with NIDCM were analyzed. Late gadolinium enhancement (LGE) presence and extent (per 1%) were associated with higher all-cause mortality (hazard ratio [HR], 1.81 [95% CI, 1.60-2.04]; p < 0.001 and HR, 1.07 [95% CI, 1.02-1.12]; p = 0.02, respectively), CV mortality (HR, 2.43 [95% CI, 2.13-2.78]; p < 0.001 and HR, 1.15 [95% CI, 1.07-1.24]; p = 0.01), arrhythmic events (HR, 2.69 [95% CI, 2.20-3.30]; p < 0.001 and HR, 1.07 [95% CI, 1.03-1.12]; p = 0.004), and HF events (HR, 1.98 [95% CI, 1.73-2.27]; p < 0.001 and HR, 1.06 [95% CI, 1.01-1.10]; p = 0.02). Left ventricular ejection fraction (LVEF) (per 1%) was not associated with all-cause mortality (HR, 0.99 [95% CI, 0.97-1.02]; p = 0.47), CV mortality (HR, 0.97 [95% CI, 0.94-1.00]; p = 0.05), or arrhythmic outcomes (HR, 0.99 [95% CI, 0.97-1.01]; p = 0.34). Lower risks for HF events (HR, 0.97 [95% CI, 0.95-0.98]; p = 0.002) and MACE (HR, 0.98 [95% CI, 0.96-0.99]; p < 0.001) were observed with higher LVEF. Higher native T1 relaxation times (per 10 ms) were associated with arrhythmic events (HR, 1.07 [95% CI, 1.01-1.14]; p = 0.04) and MACE (HR, 1.06 [95% CI, 1.01-1.11]; p = 0.03). Global longitudinal strain (GLS) (per 1%) was not associated with HF events (HR, 1.06 [95% CI, 0.95-1.18]; p = 0.15) or MACE (HR, 1.03 [95% CI, 0.94-1.14]; p = 0.43). Limited data precluded definitive analysis for native T1 relaxation times, GLS, and extracellular volume fraction with respect to mortality outcomes.
Conclusions:
The authors report that the presence and extent of LGE were associated with various adverse clinical outcomes, whereas LVEF was not significantly associated with mortality and arrhythmic endpoints in NIDCM.
Perspective:
This study reports that both presence and extent of LGE were associated with all-cause mortality, CV mortality, arrhythmia, HF events, and MACE. Of note. higher LVEF was associated with lower risk for HF events and MACE, but had no significant association with all-cause mortality, CV mortality, and arrhythmic risk. Enhanced risk stratification and refined selection of implantable cardioverter-defibrillator (ICD) candidates through CMR imaging may avert considerable costs related to unnecessary ICD implantations and subsequent lifetime management (generator changes, lead revisions, procedural and infectious complications), while allowing life-saving treatment for sudden cardiac death (SCD)-prone patients with NIDCM not captured by current selection criteria. Ongoing randomized clinical trials will provide additional insights into whether LGE-based risk stratification can optimize therapeutic decision-making regarding prophylactic ICD implantation in advanced NIDCM.
Clinical Topics: Heart Failure and Cardiomyopathies, Noninvasive Imaging, Acute Heart Failure, Magnetic Resonance Imaging
Keywords: Cardiomyopathy, Dilated, Heart Failure, Magnetic Resonance Imaging
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