Correlation Perspectives for the Diagnosis of Idiopathic Triglyceride Deposit Cardiomyovasculopathy

Background: Triglyceride (TG) deposit cardiomyovasculopathy (TGCV) is a novel cardiovascular disorder and was recently encoded as an orphan disease in Europe (ORPHA code: 565612). Defective lipolysis results in TG accumulation in the myocardium and coronary arteries in TGCV. The myocardial washout rate (WR) of iodine-123-β-methyl iodophenyl-pentadecanoic acid (BMIPP) is an essential indicator to evaluate myocardial lipolysis in vivo. TGCV is classified into primary and idiopathic type with and without PNPLA2 mutation, respectively. Here, we present the clinical correlation perspectives of TGCV patients in Chiba, Japan, to increase the awareness of this orphan disease and facilitate its diagnosis. Methods: We enrolled 234 patients who underwent BMIPP scintigraphy between September 2015 and July 2019. The diagnosis of TGCV was made based on the criteria we reported previously. Blood smear tests were performed for TGCV classification. The distributions of TGCV in each comorbidity were investigated. Results: In total, 104 patients were diagnosed with definitive idiopathic TGCV (I-TGCV). They had various comorbid conditions, including heart failure with reduced ejection fraction and multivessel coronary artery disease requiring revascularization. Moreover, the serum TG levels in I-TGCV patients were not high, and there was no correlation between serum TG level and BMIPP WR (n=205, p-value=0.31), supporting the pathophysiological hypothesis of TGCV. Conclusion: I-TGCV patients showed multiple coexistence of coronary artery disease, heart failure of unknown etiology, or diabetes mellitus. For patients with such clinical characteristics, BMIPP scintigraphy and calculation of WR should be considered proactively for the diagnosis of TGCV.