Validation of the Transthyretin Amyloidosis Cardiomyopathy Score in A Black and Hispanic Screening Population: an Interim Analysis of the First 342 Cases from the Scan-mp Study

Introduction The transthyretin amyloidosis cardiomyopathy (ATTR-CM) score was developed at the Mayo Clinic to identify high-risk patients for ATTR-CM. However, its performance in populations comprised of minoritized patients is unknown. Methods The Screening for Cardiac Amyloidosis with Nuclear Imaging in Minority Populations (SCAN-MP) study uses nuclear scintigraphy to identify ATTR-CM in Black or Caribbean Hispanic subjects age ≥60 years with heart failure. In the first 342 subjects, we calculated the ATTR-CM score as published with age (60-69 years: 2 points, 70-79 years: 3 points, ≥80 years: 4 points), gender (male: 2 points), hypertension (prior history: -1 point), ejection fraction [EF] (<60%: 1 point), posterior wall thickness [PWT] (≥12 mm: 1 point), and relative wall thickness [RWT] (>0.57: 2 points). Clinical characteristics for ATTR-CM score <6 and ≥6 groups were compared. Binary logistic regression was performed to assess the relationship between ATTR-CM score and a diagnosis of ATTR-CM on nuclear scintigraphy. ROC curves were constructed, with sensitivity, specificity, positive and negative predictive values (PPV, NPV) calculated for ATTR-CM score ≥6. Results In our cohort, 114 (33%) subjects had ATTR-CM score ≥6. Compared to those with ATTR-CM score <6, individuals with ATTR-CM score ≥6 were older (77 vs 69 years) and mostly male (78.1% vs 39.5%), with lower BMI, worse renal function, and higher cardiac biomarkers. On echocardiography, this group also had lower EF (59% vs 62%), greater PWT (1.4 vs 1.1 cm) and RWT (0.62 vs 0.51), larger atrial volumes, more impaired relaxation with elevated filling pressures, and lower TAPSE. On logistic regression, per point increase in ATTR-CM score had an unadjusted OR=2.83, p<0.001, for identification of ATTR-CM, with good calibration by Hosmer-Lemeshow test (χ2=2.843, p=0.724). ROC curve (Figure 1) for ATTR-CM score is shown, with ATTR-CM score ≥6 having sensitivity 94.1%, specificity 69.8%, PPV 14.0%, NPV 99.6%, at an overall ATTR-CM prevalence of 5%. Conclusions The ATTR-CM score is a simple, reliable clinical tool that can be accurately used in a Black and Hispanic population to screen for ATTR-CM, with ATTR-CM <6 having high NPV for excluding the disease. Performance characteristics were similar when compared to the original cohort from the Mayo clinic.