Abstract 13801: Predictive Value of Apical Sparing on Echocardiography for Cardiac Amyloidosis

Abstract

Introduction: In prior studies of patients with left ventricular thickness, the 2D speckle tracking strain echocardiography (STE) finding of relative apical sparing of longitudinal strain (RALS) was associated with a high sensitivity and specificity for diagnosing cardiac amyloidosis (CA). Use of STE is increasing, but the positive predictive value (PPV) of RALS for identifying CA among other etiologies in a large, contemporary patient population is unknown. Hypothesis: While RALS will still carry high predictive value for diagnosing CA, a significant proportion of patients will have other identifiable etiologies. Methods: We retrospectively reviewed 97 patients with RALS (defined as strain ratio ≥ 2.0) on echocardiography between June 2017 and June 2020 who had workup for CA, with cardiac MRI, 99m Technetium-pyrophosphate scan, serum/urine protein electrophoresis, and/or biopsies. These patients were then categorized into 4 groups relative to suspicion for CA (confirmed, suspicious, unlikely, ruled out). Patients without CA (unlikely/ruled out) were screened for comorbidities, including potential etiologies of RALS. Results: Of the 97 patients included, 40 (41%) were women and 39 (40%) were black. 17 (18%) had confirmed and 8 (8%) had suspicious CA while 72 (74%) had unlikely or ruled out CA. Of the confirmed cases, 10 (10%) were diagnosed with TTR amyloidosis and 7 (7%) were diagnosed with AL amyloidosis. The PPV of RALS for CA was 26% (25/97). Among the 72 patients with RALS without CA, 17 (24%) had no comorbidity, 4 (6%) had chronic kidney disease (CKD), 17 (24%) had hypertension (HTN), 16 (22%) had CKD and HTN, 2 (3%) had a malignancy treated with chemotherapy, 1 (1%) had aortic stenosis (AS), and 15 (24%) had multiple comorbidities (Figure 1). Conclusions: In a patient population with non-selective use of STE, the PPV of RALS for CA was 26%. Given the increasing use of STE, recognition of other etiologies of RALS should be noted.