32 Sex-specific cardiac magnetic resonance pulmonary capillary wedge pressure model predicts outcomes in heart failure: a multi-centre study

Introduction Non-invasive imaging is routinely used to estimate left ventricular (LV) filling pressure (LVFP) in heart failure (HF). Cardiovascular magnetic resonance (CMR) is emerging as an important imaging tool for sub-phenotyping HF and estimating pulmonary capillary wedge pressure (PCWP), a surrogate for LVFP.¹ This research sought to investigate the following questions: 1) Does sex (male/female) influence CMR-derived PCWP? 2) Compared to a previously validated generic CMR-derived PCWP model,¹ does the use of a sex-specific model improve precision? 3) Is a novel sex-specific CMR-modelled PCWP prognostically significant? Materials and Methods A derivation cohort (Norwich) involving patients with suspected HF underwent invasive right heart catheterisation and CMR within 24 hours of each other (figure 1A). This cohort was used to develop a sex-specific CMR model to estimate PCWP. The sex-specific CMR-derived PCWP model was developed using stepwise multivariate regression, using CMR variables significantly associated with PCWP during multivariate linear regression. A validation cohort (Sheffield) of patients with confirmed heart failure underwent CMR (figure 1B) and was used to evaluate for the primary end-points of heart failure hospitalisation and MACE (composite cardiovascular death, HF hospitalisation, non- fatal stroke and myocardial infarction). A comparison in the prognostic performance between the generic model and the novel sex-specific CMR-derived PCWP models was performed. Results 835 subjects were recruited from the Sheffield centre (derivation), and 454 subjects were recruited from the Leeds centre (validation). Sex (male/female) does influence CMR-derived PCWP, since left atrial volume (LAV) and left ventricular mass (LVM) are higher in men (figure 1C). A novel sex- specific model incorporating LAV and LVM was created: Sex-specific PCWP = 5.8 + (0.075*LAV) + (0.05*LVM) – (1.99*sex) [F=0; M=1] Applying the generic CMR model resulted in significant differences in PCWP between males and females (14.7±4 versus 13±3 mmHg, p>0.001). Using the sex- specific model, CMR-derived PCWP was comparable between males and females (14.1±3 versus 13.8 mmHg, p=0.3), highlighting its excellent performance (figure 1D). Notably, there was no difference in invasive PCWP assessment between males and females (13.7±6 versus 14.0±6 mmHg). In the validation cohort, the sex-specific model was associated with HF hospitalisation (hazard ratio 3.9, p=0.0002) and MACE (hazard ratio 2.5, p=0.001) over a mean follow-up period of 2.4±1.2 years (figure 1E and F). This was not the case for the generic CMR-derived PCWP. Conclusion A sex-specific CMR-derived PCWP model improves precision and prognostication in heart failure compared to a generic CMR-derived PCWP model. Acknowledgements Nil. Reference Garg P, Gosling R, Swoboda P, et al. Cardiac magnetic resonance identifies raised left ventricular filling pressure: prognostic implications. Eur Heart J. 2022:ehac207.