A review of routine bone scintigraphy reports for identification of incidental myocardial tracer uptake indicating cardiac amyloidosis

Abstract Background Whole body bone scans are widely performed in the elderly population for numerous clinical indications. Myocardial bone tracer uptake may indicate cardiac amyloid and is known to be particularly sensitive for identification of transthyretin amyloid cardiomyopathy (ATTR-CM), an increasingly recognised cause of heart failure. Data on the true prevalence of ATTR-CM are lacking and the condition continues to go undiagnosed despite availability of disease-modifying therapy. Purpose To review archived bone scan reports from a single NHS Trust to identify patients in whom incidental myocardial tracer uptake was noted indicating possible cardiac amyloidosis. Methods A retrospective review of whole body bone scan reports was performed in individuals aged ≥65 years from a single NHS Trust using multiple keyword searches. All images in which cardiac amyloid was suspected on the basis of the search were reviewed to confirm presence or absence of myocardial tracer uptake. Results A total of 11,832 bone scan reports on 9098 patients were included in the search. Uptake was identified in 63 (0.69%) patients thereby raising a suspicion of cardiac amyloidosis. Of these, 97% were male, median age was 86 yrs, 77% were of white ethnicity and the most common clinical indication for bone scintigraphy was prostate cancer (75%). Among 5678 males scanned, 1.07% had myocardial uptake noted. Review of positive scans were Perugini grade 1 and 2 in 32% and 62% respectively with myocardial uptake unable to be confirmed in 4 patients. Twelve patients had been subsequently referred (median time to referral 4 months) to a specialist amyloidosis centre following their bone scan among whom 10 were diagnosed with wild-type ATTR-CM and two with hereditary ATTR-CM. Thirty-three patients were deceased at the time of the analysis with a median time from bone scan to death of almost 2 years. Conclusions Despite the inherent limitations of this retrospective analysis, this study further suggests that there may be large numbers of undiagnosed patients with ATTR-CM who may benefit from disease-modifying treatment.