Degree of mitral regurgitation and left ventricular scarring are more powerful predictors of long-term outcomes than volumes and sphericity: a multi-modality imaging study in patients with severe ischemic cardiomyopathy

Background

Patients with ischemic cardiomyopathy (ICM) and severe left ventricular (LV) systolic dysfunction exhibit adverse left ventricular (LV) remodeling, with increasing sphericity, which predicts long-term mortality. Myocardial scarring, measured accurately by delayed hyperenhancement cardiac magnetic resonance (DHE-CMR), and mitral regurgitation (MR), also predicts outcomes in such patients.

Objective

In patients with severe ICM, we sought to assess the impact of LV sphericity, myocardial scarring (both measured on CMR) and MR (measured on Doppler echocardiography), on long-term survival.

Methods

Patients (n = 326) with > 70% disease in ≥ 1 epicardial coronary artery (77% men, median age 66 years and median LV ejection fraction or EF of 22%) undergoing Doppler echocardiography and CMR (Siemens 1.5-T scanner, Erlangen, Germany) were studied. CMR evaluation included long and short axis assessment of LV function on balanced steady state free precession images along with assessment of myocardial scar (on phase-sensitive inversion recovery DHE-CMR sequence ~10-20 minutes after injection of 0.2 mmol/kg of Gadolinium dimenglumine). Scar was measured automatically measured as > 2 SD above viable myocardium. LV scar score (defined as summed segmental scar score per patient divided by 17, with maximum being 4) was recorded on DHE-CMR images as: 0 = none, 1 = 1-25%, 2 = 26-50%, 3 = 51-75%, and 4 = > 75%; and subdivided into 7 anterior, 5 inferior and 5 lateral segments. LV volumes and LV ejection fraction were calculated. LV sphericity was measured on end-diastolic 4-chamber cine view as D1+D2+D3/3L (Figure 1). LV volumes and sphericity was indexed to body surface area. Vena contracta (cm) was measured on Doppler echocardiography. A composite end-point of cardiac transplantation and all-cause mortality was recorded.

Figure 1

Figure 1

Results

Over a follow-up of 4.0 years [interquartile range 2.6, 5.1], there were 92 events (87 deaths and 5 cardiac transplantations). Results of Univariable Cox Proportional survival analysis are shown in Table 1. However, on multivariable survival analysis, only age (hazard ratio or HR 1.04 [1.02-1.06], p < 0.001), gender (HR 2.04 [1.33-3.14], p < 0.001), vena contracta (HR 4.60 [2.32-9.14], p < 0.001) and inferior scar score (HR 1.27 [1.09-1.49], p = 0.002); and not LV volumes or sphericity remained significant predictors of outcomes (C-index 0.77 and chi-square of overall model 50.17, p < 0.001).

Table 1 Table 1

Conclusion

In ICM patients with severe LV dysfunction, degree MR and myocardial scarring (particularly inferior scar) are better predictors of long-term outcomes, as compared to LV volumes, EF or sphericity.