Evaluation of the 2021 ESC recommendations for family screening in hereditary transthyretin cardiac amyloidosis

Abstract Background The 2021 European Society of Cardiology (ESC) screening recommendations for individuals carrying a pathogenic transthyretin amyloidosis (ATTR) variant (ATTRv) are based on expert opinion. We aimed to (1) determine the yield of ATTR cardiomyopathy (ATTR-CM) at baseline; (2) evaluate the performance of the 2021 ESC position statement on initiating screening for ATTRv carriers; (3) establish the value of first-line tests recommended in ATTRv carriers; and (4) examine the yield of serial evaluation. Methods We included 159 relatives (median age 55.6 [interquartile range 43.2-65.9] years, 52% male) at-risk for developing ATTR-CM from 10 centres. ATTR-CM diagnosis was defined as the presence of either 1) cardiac tracer uptake in bone scintigraphy as recommended; or 2) cardiac biopsy proven positive for ATTR. Our secondary endpoint was a composite of heart failure symptoms (NYHA class³II) and conduction disorders necessitating pacemaker implantation. An individual fulfilled screening criteria as proposed by the 2021 ESC position statement if: 1) cardiac screening was performed ~10 years prior to disease onset in the proband (or in other individuals with the same variant if disease onset in the family was unknown); or 2) had extracardiac amyloidosis as diagnosed by a Neurologist or Ophthalmologist. Results At baseline, 40/159 (25%) relatives were diagnosed with ATTR-CM. Of those 40 relatives, 20 (50%) met the secondary endpoint. Relatives diagnosed with ATTR-CM were significantly older (66.5 [61.0-75.2] vs. 49.2 [40.8-58.8] years, p<0.001)(Figure 1A). Figure 1B-C visualizes the yield of screening by screening indications of the 2021 ESC position statement. Both screening for age, extra-cardiac amyloidosis or both age and extra-cardiac amyloidosis as indication to screen had a 31% (n=17/54), 18% (n=2/11) and 68% (n=19/28) yield of ATTR-CM, respectively. Diagnosis of ATTR-CM in relatives without an indication to screen was rare (3%; n=2/66). As a result, indication to screen as proposed by the 2021 ESC position statement yielded an almost excellent negative predictive value (97%). Other independent pre-screening predictors were infrequently identified variants and male sex. Of note, 13% of relatives with ATTR-CM did not show any "red flags" of cardiac amyloidosis on electrocardiogram (ECG), echocardiogram, and laboratory parameters. Excluding those who meet the secondary endpoint (i.e. those who already should have been diagnosed based on symptoms), ATTR-CM diagnosis in the absence of "red flags" increased from 13% to 26%. The yield of repeat bone scintigraphy (n=41 ATTRv carriers; follow-up 3.1 [2.2-5.2] years) at 3-years’ interval was 9.4% (Figure 2). Conclusion The recommendations made by the 2021 ESC position statement are adequate. Clinicians should adhere to the 3-year repeat bone scintigraphy as progressing to ATTR-CM in the absence of "red flags" and symptoms is not uncommon.Cardiac amyloidosis at baselineATTR-CM development during follow-up