170 Non-invasive assessment of stroke work using cardiac magnetic resonance imaging

Introduction Although widely adopted in clinical practice, the left ventricular ejection fraction (LVEF) has significant limitations heart failure assessment1. Gold standard physiological measures of function utilise pressure-volume (PV) loops, particularly stroke work (SW), represented as area bounded by loop. Invasive assessment PV-loops precludes its wide-spread use. Cardiac magnetic resonance (CMR) imaging allows accurate volumetrics and recent studies have found it useful estimating filling pressure2. We hypothesise that non-invasive parameters can be used to accurately estimate SW. Methods In Wellcome Trust PREFER-CMR study (NCT05114785) invasive were collected using impedance catheters (7-Fr PV-Loop Catheter CA-71103-PL; CD Leycom, NL) from 8 patients who also underwent CMR within 4 hours, which then analysed custom algorithms MATLAB. A non-invasive, method SW was developed peripheral blood pressure. This subsequently applied a large retrospective cohort 835 pulmonary hypertension had undergone both pressure at Sheffield Pulmonary Vascular Disease Unit2. Correlations assessed Pearson Correlation Coefficient. Variables normalised prior backward conditional multivariate Cox regression. All received ethical approval (REC: 21/NE/0149, 16/YH/0352). Results correlated with (typical loop shown Figure 1) small discovery catheter (r=0.861, P=0.006) no difference demonstrable (Mean 1.298±0.13J vs. 1.228±0.14J, paired t-test p=0.350). Non-invasive significantly hybrid invasive/CMR-derived PV-loop (r=0.995, p<0.001). Univariate regression analysis demonstrated risk all cause death associated reduced SW, increased CMR-derived capillary wedge (PCWP) LVEF, having greatest effect size (Table 1). On regression, age, male sex, PCWP remained independently predictive overall whilst LVEF did not For 1-year mortality, only age sex significant, excluded 2). ROC curve gave an under 0.634 for isolation 0.767 model (Figure 2A) mortality. Using score based on cut-off value >1.45 is 2B demonstrating survival. Conclusions combination simple able cardiac Such amenable high throughput artificial intelligence assisted application management. References Marwick TH. Ejection Fraction Pros Cons: JACC State-of-the-Art Review. J Am Coll Cardiol. 2018 Nov 6;72(19):2360-2379. doi: 10.1016/j.jacc.2018.08.2162. Garg P, et al. identifies raised pressure: prognostic implications. Eur Heart J. 2022 Jul 7;43(26):2511-2522. Conflict Interest Nil