Introduction and Aims: Visualizing impaired myocardial fatty acid metabolism by single-photon emission computed tomography (SPECT) using the iodinated fatty acid analogue, iodine-123-β-methyl iodophenyl-pentadecanoic acid (BMIPP), can help to identify patients at high risk of cardiac death among asymptomatic patients on hemodialysis who have not been treated by coronary intervention and among those with coronary revascularization achieved by percutaneous coronary intervention. In the present study, we investigated whether the impaired patterns of myocardial fatty acid imaging are associated with the cardiac deaths in hemodialysis patients without obstructive coronary artery disease, and further examined whether the predictive potential of impaired fatty acid imaging for cardiac deaths differed in the perfusion areas of the three coronary arteries.
Methods: We prospectively enrolled 155 hemodialysis patients without obstructive coronary artery disease, who had been examined by SPECT using the iodinated fatty acid analogue, BMIPP. Uptake of BMIPP on SPECT was graded in 17 segments on a five-point scale (0, normal; 4, absent) and assessed as BMIPP summed scores. Of the enrolled 155 participants, we analyzed 95 who had BMIPP summed scores ≥6 (52 men and 43 women, 65 ± 11 years). BMIPP scores ≥2 in ≥2 consecutive segments in SPECT was defined as focal, and the others as non-focal pattern.
Results: Of 95 participants analyzed, 42 (44.2%) showed focal and 53 (55.8%) non-focal type. During follow-up for 5.1 ± 2.0 years, 42 died of cardiac events. The occurrence of cardiac death was higher in the focal than in the non-focal group (30/42 [71.4%] versus 12/53 [22.6%], P = 0.001). In stepwise Cox hazard analysis, focal pattern was associated with cardiac death (hazard ratio 2.266), independently of impairment of BMIPP SPECT (BMIPP summed scores ≥12). In Kaplan-Meier survival analysis, cardiac death-free survival rates for 5 years were lowere in the focal than in the non-focal group (43.7% versus 77.2%, P = 0.001) (Fig). The predictive potential of BMIPP SPECT for cardiac death evaluated by receiver operating characteristic analysis was higher (P<0.001) in the left anterior descending artery (LAD) area compared with other coronary territories like right coronary artery (RCA) or left circumflex artery (LCX) (Fig).
Conclusions: Focal impairment in myocardial fatty acid imaging in the left anterior descending artery area may strongly predict cardiac death in this population.
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