Validation of the Kumamoto criteria for prediction of 99m technetium pyrophosphate scintigraphy positivity as a strategy for diagnosis of transthyretin cardiac amyloidosis: A retrospective cohort study in Kochi.

• We validated the Kumamoto criteria for prediction of technetium-99m pyrophosphate (^99mTc-PYP) positivity. • The Kumamoto criteria were useful to predict ^99mTc-PYP positivity in our cohort. • Notably, high-sensitivity cardiac troponin T ≥0.0308 ng/ml had a high potential to predict ^99mTc-PYP positivity. Early diagnosis of transthyretin cardiac amyloidosis (ATTR-CA) is important. The aim of this study was to validate the 'Kumamoto criteria' for prediction of technetium-99m pyrophosphate (^99mTc-PYP) scintigraphy positivity. One hundred fifty patients (median age: 79.4 years, 117 males) with the possibility of ATTR-CA who underwent ^99mTc-PYP scintigraphy were assessed. We divided the patients into 4 groups (groups with score of 0–3) according to the Kumamoto criteria by total points for the following 3 factors: high-sensitivity cardiac troponin T (hs-cTnT) ≥0.0308 ng/ml, left ventricle posterior wall thickness ≥13.6 mm, and wide QRS (QRS ≥ 120 ms). Seventy patients (46.7%) were positive for ^99mTc-PYP scintigraphy. ^99mTc-PYP positivity rates in the groups with score of 0, 1, 2, and 3 were 4%, 39%, 69%, and 89%, respectively. Compared with the original Kumamoto cohort, our patients in the score 1 group showed a relatively high rate of ^99mTc-PYP positivity because hs-cTnT as one of the positive factors had high ability to discriminate the disease. The sensitivity and negative predictive value of hs-cTnT ≥0.0308 ng/ml for ^99mTc-PYP positivity were 97.1% and 93.9%. In the Kochi validation cohort, the Kumamoto criteria were useful for predicting ^99mTc-PYP positivity. However, patients in the score 1 group should be assessed cautiously for the possibility of ATTR-CA if the hs-cTnT value is high. [ABSTRACT FROM AUTHOR]