MRI staging of haemodynamic congestion and clinical outcomes.

Abstract

To evaluate the prognostic value of cardiovascular magnetic resonance imaging (MRI)-derived left ventricular filling pressure (MRI-wedge) and pulmonary blood volume index (PBVi), and to assess their association with non-invasive markers of myocardial fibrosis. MRI-wedge pressure was computed from left-atrial volume and left-ventricular mass, and PBVi was measured from first-pass transit analysis. Patients were assigned to one of four MRI haemodynamic stages based on normal or elevated MRI-wedge and PBVi: stage 1 (normal profile), stage 2 (isolated volume overload), stage 3 (isolated pressure overload), and stage 4 (combined overload). Non-invasive myocardial tissue indices and clinical outcomes were compared across stages. The primary endpoint was a composite of cardiovascular death and cardiac hospitalisation. Among 262 participants (mean age 52 ± 17 years; 34% women), mean MRI-wedge was 13.4 ± 2.3 mmHg and mean PBVi was 333 ± 150 mL/m². Higher MRI-wedge values were associated with greater PBVi and prolonged pulmonary transit time (both p < 0.001) and increased in parallel with native T1 mapping and indexed extracellular volume (iECV, both p < 0.001). Over a median follow-up of 30 months, 29 patients (12%) met the primary endpoint. Event-free survival was reduced in patients with MRI-wedge ≥ 15 mmHg, PBVi ≥ 492 mL/m², and iECV ≥ 16 mL/m², and declined progressively across MRI haemodynamic stages, with stage 4 having the lowest survival (p < 0.001). In multivariable analysis, the MRI-based haemodynamic congestion staging system (p = 0.009) and iECV (HR 1.072; 95% CI 1.003-1.146; p = 0.04) each remained independent predictors of adverse events. MRI-wedge, PBVi and iECV capture complementary and progressive biological features of haemodynamic congestion-from early structural adaptation to overt circulatory overload-and identify patients at increased risk of adverse clinical events. Question How do MRI-derived markers of haemodynamic congestion relate to one another, and can their integration improve non-invasive prognostic stratification? Findings Higher MRI-wedge was associated with increased PBVi, prolonged pulmonary transit time, and extracellular matrix expansion. A four-stage haemodynamic congestion grading framework predicted clinical outcomes. Clinical relevance An integrated MRI-based system combining filling-pressure surrogates and pulmonary blood volume identifies progressively higher haemodynamic congestion states, while iECV provides complementary tissue-level prognostic information.