Prevalence, adequacy and adherence of anticoagulation for stroke thromboprophylaxis in minority patients with atrial fib referred for transthyretin cardiac amyloidosis screening: The SCAN-MP Study

Abstract Introduction/Background Atrial fibrillation (AF) is the most common arrhythmia in adults, confers a 5-fold increase in risk of stroke, and is present in up to 50% of patients with transthyretin cardiac amyloidosis (ATTR-CA). 1,2 When present in ATTR-CA, AF is associated with a significant risk of stroke and systemic thromboembolism, even independent of CHA2DS2VASc score. 2-4. Current guidelines advocate the use of oral anticoagulant therapy in all patients with ATTR-CA and AF, without a contraindication for such treatment. Up to 50% of patients with an escalated risk for systemic thromboembolism may not be receiving appropriate anticoagulation, but less is known about patterns and adequacy of anticoagulation in minority patients, specifically Black/Hispanic patients with suspected amyloidosis and AF. 5,6. Methods We conducted a retrospective study of patients in SCAN-MP (Screening for Cardiac Amyloidosis with Nuclear Imaging in Minority Populations) who were ≥60 years of age with heart failure, Black or Hispanic, with an EF >30% and increased left ventricular wall thickness, (n=431) from 4 large urban hospitals who had documented AF in their medical records. We assessed the prescription of anticoagulation in participants stratified by the CHA2DS2VASc score and whether they received an appropriate dose (versus inappropriately low or high dose, when adjusted for renal function for dabigatran, edoxaban, and rivaroxaban; for renal function, age, and weight for apixaban). Results 122 subjects (28.3%) had a history of atrial fibrillation and of that number, 25.4% (n=31) were either not receiving any treatment (n=14) or only received a single anti-platelet therapy (n=17) for stroke thromboprophylaxis. Among participants with AF, patients with a CHA2DS2VASc of 6-9 (n=27), 21 patients (77.8%) were receiving an oral anticoagulant (either VKA or DOAC) either alone or in combination with antiplatelet therapy (Table 1). Among patients with CHA2DS2VASc of 2-5 (n=95), 70 patients (73.7%) were receiving such therapy. Among patients receiving a DOAC (n=74), dosing was incorrect in 20.3% (n=15). There were a significant proportion of patients receiving antiplatelet therapy in combination with oral anticoagulant (n=30, 24.5%). Among these patients receiving both therapies, only about half (n=16, 53.3%) had some form of vascular disease, coronary artery disease and/or peripheral arterial disease (Table 2). Conclusions These data suggest that thromboprophylaxis in Black and Hispanic patients with AF and suspected amyloidosis with heart failure is better than the often ≤50% historically reported in the literature. 6 Nearly ¼ of patients were receiving both antiplatelet and anticoagulant therapy, even though only half had documentation of vascular disease. Factors underlying this observation requires additional study, but the indication for such dual anti-thrombotic therapy is limited, may be associated with harm 7, and is an opportunity for improvement.Anti-thrombotic regimens in patientsTable 2:Frequency of vascular disease