MRI staging of haemodynamic congestion and clinical outcomes

Objectives

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.

Materials and methods

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.

Results

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.

Conclusions

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.

Key Points

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.

Graphical Abstract