Atrial Fibrillation and Stroke Burden: A Comparison of African American and Caucasian Patients with Transthyretin Cardiac Amyloidosis

The diagnosis of amyloidosis is challenging due to the highly varied nature of its presentation and underestimated prevalence in the clinical setting. In part this is due to an underappreciation of potential clinical correlates and nonspecific clinical presentation.1

The overall prevalence of transthyretin cardiac amyloidosis (ATTR-CM) within African American and Caucasian populations is unclear, despite being frequently correlated with both strokes and atrial fibrillation. Lindsey Mitrani, MD, Columbia University Irving Medical Center, and colleagues presented data exploring differences between populations of patients with ATTR-CM, noting that although African Americans are at an increased risk of stroke and stroke-related death, atrial fibrillation, a common cause of stroke, affects twice as many Caucasians compared with African Americans.2

In this retrospective review, patients (N = 290) with ATTR-CM were identified; atrial fibrillation presence in all patients was determined by ECG or clinical history or a combination of both. Incident stroke cases, transient ischemic attack (TIA), and major bleeding (hospitalization, transfusion, or intracranial bleed) were also identified.

In the study, 24.8% (72) of patients were African American, 71.3% (207) were Caucasian, and 3.8% (11) of patients identified as “other.” The diagnosis of atrial fibrillation within these 2 main groups differed significantly, with 58.3% (42) of African Americans being diagnosed with atrial fibrillation compared with 79.7% (165) of Caucasian patients (P <.001).

Wild-type ATTR-CM prevalence also differed significantly between these 2 populations. It was found in 13.9% (10) of African American patients compared with 86.5% (179) of Caucasian patients (P <.001). Oral anticoagulants were prescribed at a lower rate to African Americans at 40.5% (17) compared with 57.8% (95) of Caucasians (P = .047). However, no significant differences in bleeding were found, occurring in 4.7% of the African American and 11.5% of the Caucasian populations (P = .26). The 2 groups also experienced similar rates of stroke and TIA. Over a period of 28 ± 26 months, 14.2% (6) of African Americans experienced an event compared with 6% (10) of Caucasians (P = .10).

The authors concluded that African American patients with ATTR-CM experience lower rates of atrial fibrillation and are less likely to have been prescribed oral anticoagulants compared with Caucasians, despite having similar rates of major bleed, TIA, and incident stroke.

References

  1. Ihne S, Morbach C, Sommer C, et al. amyloidosis-the diagnosis and treatment of an underdiagnosed disease. Dtsch Arztebl Int. 2020;117:159-166.
  2. Mitrani L, Ruberg FL, De Los Santos J, et al. African Americans present with less atrial fibrillation in transthyretin cardiac amyloidosis: a retrospective review. Presented at: American College of Cardiology/World Congress of Cardiology 2020 Virtual Meeting. Abstract 1260-154.

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