Combined evaluation of right ventricular function using echocardiography in non-ischaemic dilated cardiomyopathy

Abstract

Aims: Although comprehensive assessment of right ventricular (RV) function using multiple echocardiographic parameters is recommended for management of patients with non-ischaemic dilated cardiomyopathy (DCM), it is unclear which RV parameters to combine. Additionally, normalization of RV parameters by estimated pulmonary artery systolic pressure (PASP), in consideration of RV-pulmonary artery coupling, may be clinically significant. The aim of our study was to elucidate the best combination of echocardiographic RV functional parameters, with or without indexing for PASP, to predict outcome in patients with heart failure with reduced ejection fraction secondary to DCM.

Methods and results: We retrospectively analysed 109 DCM patients with left ventricular ejection fraction <40%. RV size was assessed by RV end-diastolic area (RVEDA) and RV end-systolic area (RVESA) from RV-focused apical four-chamber view. RV function was assessed by fractional area change (FAC) and tricuspid annular plane systolic excursion (TAPSE) and by RV longitudinal strain (RVLS) using two-dimensional speckle-tracking echocardiography. All functional parameters were also indexed for estimated PASP. Cox analyses were used to evaluate the association of RV morphology and functional parameters with 1 year outcome (composite of left ventricular assist device implantation and all-cause death). Area under the curve was used to compare prognostic values. Mean age was 44 ± 14 years, and 76 (69.7%) were men. Mean left ventricular ejection fraction was 21.9%, median RVEDA was 22.1 cm² , FAC was 27.0%, TAPSE was 15.0 mm, and RVLS was -12.5%. Forty-one (37.6%) patients experienced the primary outcome. Multivariate Cox analysis revealed that RVEDA, RVESA, FAC, TAPSE, RVLS, FAC/PASP, and RVLS/PASP were independent predictors for primary outcome (all P < 0.05). However, normalization with PASP did not improve area under the curve for any RV functional parameters. When we evaluate hazard ratios according to the combination of two echocardiographic parameters of RV function, patients with impairment of both FAC (<27%) and RVLS (>-8.6%) had significantly higher hazard ratio than those with either impairment alone (11.3 vs. 3.4, P < 0.001); the other combinations did not improve prognostic value.

Conclusions: Normalizing echocardiographic RV parameters for PASP did not improve the prognostic values for our population. Meanwhile, combined evaluation of FAC and RVLS improved risk stratification in patients with heart failure with reduced ejection fraction secondary to DCM.

Keywords: Dilated cardiomyopathy; Echocardiography; Pulmonary artery; Right ventricular function; Speckle-tracking echocardiography.

Figure 1

Patient flow diagram. We included 109 patients with dilated cardiomyopathy (DCM) who underwent echocardiography and management of cardiomyopathy in the final statistical analysis. LV, left ventricular; LVEF, left ventricular ejection fraction; RV, right ventricular; TRPG, tricuspid regurgitation peak gradient.

Figure 2

A representative image of right ventricular longitudinal strain (RVLS) in a dilated cardiomyopathy patient. RVLS was reduced to −17.8% suggesting impaired right ventricular systolic function in this case.

Figure 3

Comparison of hazard ratios between single parameters and the combination of conventional parameters and right ventricular longitudinal strain (RVLS). (A) When stratified by fractional area change (FAC) and RVLS, we found that patients with impaired FAC and RVLS had a significantly higher hazard ratio compared with patients with impaired FAC or RVLS (11.3 vs. 3.4, P < 0.001). (B) On the other hand, when stratified by FAC and tricuspid annular plane systolic excursion (TAPSE), patients with impaired FAC and TAPSE did not have a significantly higher hazard ratio compared with patients with impaired FAC or TAPSE (7.2 vs. 3.8, P = 0.08). (C) When stratified by TAPSE and RVLS, a similar result was found (6.9 vs. 3.2, P = 0.08). Combined evaluation of RV function with FAC and RVLS showed excellent predictive value of outcome compared with other single or combined parameters.