Development of a risk score for patients with ischaemic cardiomyopathy

Abstract

Background: Ischaemic cardiomyopathy is a leading cause of heart failure and is associated with a poor prognosis.

Aim: To evaluate predictors of major adverse cardiovascular events (MACE) and to develop a risk score for the disease.

Methods: All patients with ischaemic cardiomyopathy referred to a tertiary hospital between 2010 and 2018 for stress-rest gated single-photon emission computed tomography (SPECT) were included retrospectively (n=747). Clinical and gated SPECT-derived variables were analysed as predictors of MACE, a combined endpoint of cardiovascular mortality, heart failure hospitalization or myocardial infarction during follow-up. A multivariable Cox model using backwards stepwise regression with competing risks was used to select the best parsimonious model.

Results: After a median follow-up of 4.7 years, 313 patients had MACE (41.9%). Independent predictors of MACE were previous heart failure admission, worsening angina or dyspnoea, estimated glomerular filtration rate ≤60mL/min/1.73 m², age>73 years, diabetes, atrial fibrillation, end-diastolic volume index>83mL/m² and>12% of scarred myocardium. A risk score ranging from 0 to 12 classified patients as at intermediate risk (event rate of 4.0 MACE per 100 person-years), high risk (11.3 MACE per 100 person-years) or very high risk (27.8 MACE per 100 person-years). The internally validated area under the curve was 0.720 (95% confidence interval 0.660-0.740) and calibration was adequate (Hosmer-Lemeshow test P=0.28) for MACE.

Conclusions: In patients with ischaemic cardiomyopathy, a simple risk score using dichotomic and readily available variables obtained from clinical assessment and gated SPECT accurately predicts the risk of MACE.

Keywords: Ischaemic cardiomyopathy; Prognosis; Risk score; SPECT.