Abstract 6126: Clinical Significance of Serial Studies of Cardiac I-123 Metaiodobenzylguanidine Imaging for the Prediction of Sudden Death in Patients with Chronic Heart Failure
Background: Cardiac I-123 metaiodobenzylguanidine(MIBG) imaging provides prognostic information in patients with chronic heart failure(CHF). However, it remains unclear whether serial studies of cardiac MIBG imaging could improve the prediction of clinical outcome in CHF patients.
Methods: We prospectively studied 106 CHF outpatients with radionuclide left ventricular ejection fraction less than 40% (30±7%). The cardiac MIBG imaging was performed at the entry and repeated every year after the entry for three years. The cardiac MIBG heart to mediastinum ratio and washout rate (WR) were calculated from the chest anterior view images obtained at 20 and 200 min after isotope injection. Study patients were divided into two groups with and without abnormal WR > 27%(:the mean WR+1SD in normal subject).
Results: For a mean follow-up of 6.2±3.2 years, 29 of 106 patients had cardiac death (heart failure in 10 and sudden death in 19 patients). Kaplan-Meier analysis showed that patients with abnormal WR at the entry had a significantly higher mortality than those without abnormal WR (44%(23/52) vs 11%(6/54), p=0.0001). At Cox analysis, out of the variables including clinical, echocardiographic, hemodynamic, and MIBG parameters, WR was the only variable significantly associated with cardiac death (p=0.04). Furthermore, the cardiac death was also significantly more frequently observed in patients with than without abnormal WR at the last evaluation of MIBG study (49%(25/51) vs 7%(4/55), p<0.0001). The hazard ratio of abnormal WR at the last evaluation for cardiac death was 7.6 (95% CI 2.7–22.0), which was greater than that of abnormal WR at the entry(5.0, 95%CI 2.0–12.2). The hazard ratio of abnormal WR at the last evaluation for sudden death was 7.3 (95% CI 2.1–25.0), which was two fold of that of abnormal WR at the entry(3.6, 95%CI 1.3–10.0). On the other hand, the hazard ratio of abnormal WR at the last evaluation for heart failure death was similar to that of abnormal WR at the entry(12.0 vs 12.0).
Conclusion: Serial studies of cardiac MIBG imaging would improve the prediction of sudden death in CHF patients.