Introduction:
The cardiothoracic ratio (CTR) is a widely accepted method of quantifying cardiac size, and carries prognostic information in acquired heart disease. However, little is described in the underlying mechanism and prognostic value in heart failure with preserved ejection fraction (HFpEF).
Methods:
Analysis was performed from a prospective multicenter observational registry for HFpEF (PURSUIT-HFpEF Registry) conducted in the Osaka region of Japan. A total of 871 patients hospitalized for acute HF (diagnosed by using Framingham criteria) met the inclusion criteria: a left ventricular ejection fraction (LVEF) ≥50% and brain natriuretic peptide (BNP) ≥100 pg/ml. We included 629 patients (age, 81±9 years; men, 46%; atrial fibrillation, 37%) whose follow-up data after survival discharge were available and whose CTR were measured from posterior-anterior chest X-ray. The endpoint was defined as the composite of death, re-hospitalization for HF, and cerebrovascular accident.
Results:
Median CTR at discharge was 56% (interquartile range: 51-61%). Comparison with echocardiographic data revealed that CTR significantly correlated with increased left atrial size (left atrial volume; r = 0.39, p <0.001) and LV filling pressure (E/e’ ratio; r = 0.13, p = 0.002), but not with LV size (LV end-diastolic volume; r = -0.014; LV end-systolic volume: r = -0.002) and LVEF (r = -0.035). Age (r = 0.16, p <0.001) and log-transformed N-terminal-pro-BNP value (r = 0.21, p <0.001) were also correlated with CTR. Female patients exhibited more higher CTR than male patients (54±7 vs. 58±7%, p <0.001). During a median follow-up of 15 months, 257 patients experienced the endpoint. When patients were classified into the CTR quartile groups, there was a positive correlation between the incidence rate and the quartiles (Q1, 31.0%; Q2, 39.5%; Q3, 35.7%; Q4 55.8%, p <0.001). After adjustment for age and gender, Cox regression analysis revealed that CTR at discharge was a significant predictor of the composite endpoint (hazard ratio per quartile increase; 1.23; 95% confidence interval, 1.10-1.39; p = 0.006).
Conclusions:
CTR was not associated with LV size but left atrial size in patients with HFpEF. Increased CTR at discharge predicted unfavorable prognosis in patients with HFpEF.
Left atrial size and heart failure hospitalization in patients with diastolic dysfunction and preserved ejection fraction
