Differentiation of infiltrative cardiomyopathy from hypertrophic cardiomyopathy using high-sensitivity cardiac troponin T: a case-control study

Toru Kubo, Yuichi Baba, Takayoshi Hirota, Katsutoshi Tanioka, Naohito Yamasaki, Shigeo Yamanaka, Tatsuo Iiyama, Naoko Kumagai, Takashi Furuno, Tetsuro Sugiura, Hiroaki Kitaoka

Because infiltrative cardiomyopathy and hypertrophic cardiomyopathy (HCM) share clinical and hemodynamic features of left ventricular (LV) hypertrophy and abnormal diastolic function, it is often difficult to distinguish these entities. We investigated the potential role of high-sensitivity cardiac troponin T (hs-cTnT) for differentiation of infiltrative cardiomyopathy from HCM. The study group consisted of 46 consecutive patients with infiltrative cardiomyopathies or HCM in whom sarcomere protein gene mutations were identified at Kochi Medical School Hospital; of these, there were 11 patients with infiltrative cardiomyopathy (cardiac amyloidosis in 8 patients and Fabry disease in 3 patients) and 35 HCM patients. Serum hs-cTnT level was significantly higher in patients who had infiltrative cardiomyopathy than in those who had HCM (0.083 ± 0.057 ng/ml versus 0.027 ± 0.034 ng/ml, p < 0.001), whereas brain natriuretic peptide levels did not differ between the two groups. In two age-matched the 2 cohorts (patients evaluated at > 40 years at age), hs-cTnT level, maximum LV wall thickness, posterior wall thickness, peak early (E) transmitral filling velocity, peak early diastolic (Ea) velocity of tissue Doppler imaging at the lateral corner and E/Ea ratios at both the septal and lateral corners were significantly different between the two groups. As for diagnostic accuracy to differentiate the two groups by using receiver operating characteristic analysis, hs-cTnT was the highest value of area under the curve (0.939) and E/Ea (lateral) was second highest value (0.914). Serum hs-cTnT is a helpful diagnostic indicator for accurate differentiation between infiltrative cardiomyopathy and HCM.