Safety and prognostic value of left ventricular endomyocardial biopsy in dilated cardiomyopathy

The need to perform endomyocardial biopsy (EMB) in patients with non-ischaemic dilated cardiomyopathies (DCM) is debated. Here we sought to determine the extent of left ventricular collagen volume fraction (LV-CVF) in DCM patients and to evaluate it as a prognostic marker.

In this retrospective longitudinal study, we included 524 patients with suspected DCM who underwent left ventricular EMB (LV-EMB) as a part of their clinical work-up. LV-CVF was quantified using automated image processing of high-resolution scans of LV-EMB. Deep phenotyping was performed including assessment of late gadolinium enhancement on cardiac magnetic resonance imaging. Endpoints were (i) composite endpoint of heart failure-related death, sudden cardiac death, aborted sudden cardiac death (appropriate implantable cardioverter-defibrillator shock, reported sustained ventricular tachycardia, or cardiopulmonary resuscitation), or cardiac transplantation, and (ii) all-cause mortality. LV-EMB was associated with 0.76% major and 2.1% minor complications. No death occurred due to EMB. LV-CVF could be reliably quantified using Bayesian classification. During a median follow-up of 43.2 months (2084 patient-years), 48 patients with LV-CVF >32% and 14 patients with LV-CVF ≤32% reached the composite endpoint (log-rank p < 0.0001). A total of 62 patients reached the endpoint all-cause mortality, from which 38 presented with LV-CVF >32% and 17 with LV-CVF ≤32% (log-rank p = 0.009). In multivariable analyses, LV-CVF and N-terminal pro-B-type natriuretic peptide (NT-proBNP) (hazard ratio 2.03, 95% confidence interval 1.32-3.11) were independent predictors of unfavourable outcome.

Left ventricular EMB is a safe diagnostic procedure. The extent of CVF in LV-EMB provides prognostic information in patients with DCM in addition to existing measures of left ventricular ejection fraction or NT-proBNP.