Cardiac magnetic resonance identifies raised left ventricular filling pressure: prognostic implications

Abstract

Aims: 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. However, currently, LVFP cannot be estimated from CMR. This study sought to investigate (i) if CMR can estimate LVFP in patients with suspected HF and (ii) if CMR-modelled LVFP has prognostic power.

Methods and results: Suspected HF patients underwent right heart catheterization (RHC), CMR and transthoracic echocardiography (TTE) (validation cohort only) within 24 h of each other. Right heart catheterization measured pulmonary capillary wedge pressure (PCWP) was used as a reference for LVFP. At follow-up, death was considered as the primary endpoint. We enrolled 835 patients (mean age: 65 ± 13 years, 40% male). In the derivation cohort (n = 708, 85%), two CMR metrics were associated with RHC PCWP:LV mass and left atrial volume. When applied to the validation cohort (n = 127, 15%), the correlation coefficient between RHC PCWP and CMR-modelled PCWP was 0.55 (95% confidence interval: 0.41-0.66, P < 0.0001). Cardiovascular magnetic resonance-modelled PCWP was superior to TTE in classifying patients as normal or raised filling pressures (76 vs. 25%). Cardiovascular magnetic resonance-modelled PCWP was associated with an increased risk of death (hazard ratio: 1.77, P < 0.001). At Kaplan-Meier analysis, CMR-modelled PCWP was comparable to RHC PCWP (≥15 mmHg) to predict survival at 7-year follow-up (35 vs. 37%, χ2 = 0.41, P = 0.52).

Conclusion: A physiological CMR model can estimate LVFP in patients with suspected HF. In addition, CMR-modelled LVFP has a prognostic role.

Keywords: Cardiovascular magnetic resonance; Left ventricular filling pressure; Right heart catheterization.

Structured Graphical Abstract

Patients presenting with breathlessness underwent TTE, CMR, and RHC. Cardiovascular magnetic resonance-modelled PCWP and TTE-estimated PCWP were both compared with invasively measured PCWP. The diagnostic accuracy of our CMR model was 71% compared with 25% for TTE. In cases where TTE was non-diagnostic (indeterminate or incorrect diagnosis), CMR correctly reclassified the correct diagnosis in 71%. Furthermore, CMR-derived PCWP was an independent predictor of survival. CMR, cardiac magnetic resonance; HF, heart failure; PCWP, pulmonary capillary wedge pressure; SOB, shortness of breath; TTE, transthoracic echocardiography; RHC, right heart catheterization.

Figure 1

Study protocol. This study included patients who were referred to our centre over a 8-year period (2012–2020) for further assessment of breathlessness. Right heart catheterization and cardiac magnetic resonance were performed within 24 h in all cases. Eight hundred and thirty-five patients were included and allocated to derivation (85%) and validation (15%) cohorts. In the validation cohort, we obtained transthoracic echocardiography results within 24 h for comparison with cardiac magnetic resonance. CMR, cardiac magnetic resonance; HF, heart failure; LA, left atrial; LV, left ventricular; PCWP, pulmonary capillary wedge pressure; RHC, right heart catheterization; SOB, shortness of breath; TTE, transthoracic echocardiography.

Figure 2

(A,B) Kaplan–Meier survival curves demonstrate prognostic relevance of both invasive and non-invasive pulmonary capillary wedge pressure. (C) Cardiac magnetic resonance-derived pulmonary capillary wedge pressure was non-inferior to an invasively measured pulmonary capillary wedge pressure. (D) After adjusting for all cardiac magnetic resonance variables associated with mortality, cardiac magnetic resonance-modelled pulmonary capillary wedge pressure independently predicted outcomes. (E,F) In the validation cohort, the transthoracic echocardiography and cardiac magnetic resonance models both independently predicted outcomes. Early outcomes were better predicted with the cardiac magnetic resonance model. CMR, cardiac magnetic resonance; PCWP, pulmonary capillary wedge pressure; TTE, transthoracic echocardiography; RHC, right heart catheterization; NAR, Numbers at risk.

Figure 3

Proposed decision-making algorithm for the assessment of raised left ventricular filling pressure. -ve, negative; +ve, positive; CMR, cardiovascular magnetic resonance; LVFP, left ventricular filling pressure; SOB, shortness of breath; HF, heart failure; TTE, transthoracic echocardiography