Prognostic significance of cardiac (123)I metaiodobenzylguanidine imaging for mortality and morbidity in patients with chronic heart failure: a prospective study

Abstract

Objective: To determine whether cardiac iodine-123 metaiodobenzylguanidine ((123)I MIBG) imaging is useful in predicting the prognosis of patients with chronic heart failure.

Design: Cardiac (123)I MIBG imaging was done on entry to the study. The cardiac MIBG washout rate was calculated from anterior chest view images obtained 20 and 200 minutes after injection of the isotope. Study patients were divided into two groups with washout rates above and below 27% (the mean value + 2 SD obtained in 20 normal subjects), and were then followed up.

Setting: Tertiary referral centre.

Patients: 79 patients with chronic heart failure in whom the left ventricular ejection fraction was less than 40%.

Results: There were 37 patients in group 1 (washout rate of >/= 27%) and 42 in group 2 (< 27%). During a follow up period of between 1 and 52 months, eight patients died suddenly and five died of worsening heart failure in group 1, while none died in group 2; 13 patients in group 1 and four in group 2 were admitted to hospital for progressive heart failure. Kaplan-Meier analysis showed that group 1 had a significantly higher mortality and morbidity (p = 0.001 and p < 0.001, respectively) than group 2.

Conclusions: Cardiac (123)I MIBG washout rate seems to be a good predictor of prognosis in patients with chronic heart failure.

Figure 1

Comparison of morbidity and mortality curves between groups 1 and 2. Group 1 contained 37 patients whose cardiac MIBG washout rate was 27% or more. Group 2 contained 42 patients whose cardiac MIBG washout rate was less than 27%. Both morbidity (A) and mortality (B) were significantly higher in group 1 than in group 2 (p = 0.001 and p < 0.001, respectively).

Figure 2

Comparison of morbidity and mortality curves in the ischaemic heart disease subgroup. Group 1 of this subgroup contained 20 patients and group 2 contained 25 patients. Both morbidity (A) and mortality (B) were significantly higher in group 1 than in group 2 (p = 0.047 and p < 0.001, respectively).

Figure 3

Comparison of mortality and morbidity curves in the non-ischaemic heart disease subgroup. Both group 1 and group 2 of this subgroup contained 17 patients. Both morbidity (A) and mortality (B) were significantly higher in group 1 than in group 2 (p = 0.014 and p < 0.001, respectively).