Novel predictors of prognosis in heart failure with reduced ejection fraction and the presence of spontaneous echo contrast: shock index, modified shock index and age-adjusted shock index

Introduction:
Shock indexes (SI) have been associated with in-hospital mortality, particularly in heart failure patients.

Aim:
In our study, we aimed to investigate the relationship and prognostic value of the shock index (SI), modified shock index (MSI) and age-adjusted shock index (ASI) with spontaneous echo contrast (SEC) formation in patients with heart failure with reduced ejection fraction (HFrEF).

Material and methods:
We designed our research as a two-center, retrospective study. A total of 537 patients with left ventricular ejection fraction (LVEF) ≤ 40 and appearance of SEC within the left ventricular cavity, meeting the study criteria, were included. The primary endpoint included each component of ischemic cerebrovascular occlusion (CVO) and mortality. The secondary endpoint was considered cumulative events, which included the combination of CVO and mortality.

Results:
There were 146 patients in the group with SEC and 391 patients in the group without SEC. SI (0.65 ±0.15 vs. 0.61 ±0.14, respectively, p = 0.014), MSI (0.92 ±0.22 vs. 0.87 ±0.20, respectively, p = 0.007) and ASI (42.76 ±11.71 vs. 39.83 ±12.25, respectively, p = 0.013) were significantly higher in the group with SEC. Ischemic CVO (10.3% vs. 3.3%, p = 0.001) and mortality (34.9% vs. 24.6%, p = 0.016) were significantly higher in the SEC group. In addition, the cumulative rate of mortality and ischemic CVO (39.7% vs. 26.1%, p = 0.002) was significantly higher in the SEC group. We found that the parameters SEC (OR = 2.822, 95% CI: 1.328–5.998, p = 0.007) and ASI (OR = 1.034, 95% CI: 1.002–1.066, p = 0.038) were independent predictors of ischemic CVO.

Conclusions:
SI, MSI and ASI may be quickly accessible and calculable indices to predict SEC in HFrEF patients.