# Does CMR improve aetiological sub-phenotyping beyond echocardiography in patients with elevated LV filling pressure? A prospective registry study (PREFER-CMR)

## TL;DR

This study shows that CMR provides better diagnostic accuracy than echocardiography in patients with high heart filling pressure, identifying conditions often missed by standard tests.

## Contribution

The study demonstrates CMR's superior ability to sub-phenotype heart conditions compared to TTE in patients with elevated LV filling pressure.

## Key findings

- CMR showed diagnostic discordance with TTE in 74% of cases.
- CMR identified HFpEF and IHD in patients with normal or non-diagnostic TTE results.
- CMR detected specific cardiomyopathies in cases with non-specific TTE findings.

## Abstract

To evaluate the incremental diagnostic value and sub-phenotyping capability of Cardiovascular Magnetic Resonance (CMR) compared with Transthoracic Echocardiography (TTE) in patients with elevated left ventricular filling pressure (LVFP).

Prospective registry study. [Results from ClinicalTrials.gov ID NCT05114785]

A single NHS hospital in the UK.

The primary outcome was the rate of diagnostic discordance between TTE and CMR. Secondary outcomes included the characterisation of specific pathologies identified by CMR where TTE was normal, non-diagnostic or provided a non-specific diagnosis.

CMR demonstrated diagnostic discordance with TTE in 74% (n=194) of cases. In patients with a normal TTE (n=54), CMR identified heart failure with preserved ejection fraction (HFpEF) in 46% (n=25) and ischaemic heart disease (IHD) in 19% (n=10). For non-diagnostic TTE cases (n=15), CMR detected HFpEF in 53.3% (n=8) and IHD in 26.7% (n=4). Among those with non-specific left ventricular hypertrophy on TTE (n=47), CMR revealed HFpEF in 45% (n=21) and hypertrophic cardiomyopathy in 34% (n=16).

CMR markedly improves diagnostic precision and sub-phenotyping in patients with elevated LVFP, identifying key conditions like HFpEF, IHD and specific cardiomyopathies that TTE frequently misses. These findings highlight CMR’s critical role as a complementary imaging tool for refining diagnoses and informing management strategies in cardiovascular conditions.