Abstract
Background
A four-parameter risk model including cardiac iodine-123 metaiodobenzylguanidine (MIBG) imaging and readily available clinical parameters has been recently developed for the prediction of 2-year cardiac mortality risk in patients with chronic heart failure (CHF) using a Japanese CHF database consisting of 1322 patients. On the other hand, the Acute Decompensated Heart Failure National Registry (ADHERE) and Get With The Guidelines-Heart Failure (GWTG-HF) risk scores, simple tools to predict risk of in-hospital mortality, have been reported to be predictive of post-discharge outcome in patients with acute decompensated heart failure (ADHF). However, there is no information available on the usefulness of 2-year MIBG-based cardiac mortality risk score for the prediction of post-discharge prognosis in ADHF patients and its comparison with the ADHERE and GWTG-HF risk scores.
Purpose
We sought to validate the predictability of the 2-year MIBG-based cardiac mortality risk score for post-discharge clinical outcome in ADHF patients, and to compare its prognostic value with those of ADHERE and GWTG-HF risk scores.
Methods
We studied 297 consecutive patients who were admitted for ADHF, survived to discharge, and had definitive 2-year outcomes. Venous blood sampling was performed on admission, and echocardiography and cardiac MIBG imaging were performed just before discharge. In cardiac MIBG imaging, the cardiac MIBG heart-to-mediastinum ratio (HMR) was measured from the chest anterior view images obtained at 20 and 200 min after isotope injection. The 2-year cardiac mortality risk score was calculated using four parameters, including age, left ventricular ejection fraction, NYHA functional class, and HMR on delayed image. The patients were stratified into three groups based on the 2-year cardiac mortality risk score: low- (<4%), intermediate- (4–12%), and high-risk (>12%) groups. The ADHERE and GWTG-HF risk scores were also calculated from admission data as previously reported. The predictive ability of the scores was compared using receiver operating characteristic curve analysis. The endpoint was a composite of all-cause mortality and unplanned hospitalization for worsening heart failure.
Results
During a follow-up period, 110 patients reached the primary endpoint. There was significant difference in the rate of primary endpoint among the three groups stratified by 2-year cardiac mortality risk score (low-risk group: 18%, intermediate-risk group: 36%, high-risk group: 64%, Figure 1A). The 2-year cardiac mortality risk score demonstrated a greater area under the curve for the primary endpoint compared to the ADHERE and the GWTG-HF risk scores (Figure 1B).
Figure 1
Conclusions
The 2-year MIBG-based cardiac mortality risk score is also useful for the prediction of post-discharge clinical outcome in ADHF patients, and its prognostic value is superior to those of the ADHERE and the GWTG-HF risk scores.
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