Characteristics of Transthyretin Amyloid Cardiomyopathy in Hospitalized Patients Referred for PYP Scan

To help optimally triage patients hospitalized for decompensated heart failure referred for Tc99m pyrophosphate (PYP) scanning, Syed Bukhari, MD, Advanced Cardiology Fellow, Amyloidosis, University of Pittsburgh Medical Center, PA, and colleagues sought to better understand the prevalence, clinical features, and cardiographic characteristics of patients with transthyretin amyloid cardiomyopathy (ATTR-CA).

All the patients who were referred for PYP scan after heart failure-related hospitalization at their center between June 2015 and June 2019 were included. Each patient’s medical history was obtained via chart review. Patients with a positive PYP scan and negative serum studies for amyloid light-chain amyloidosis were diagnosed with ATTR-CA. Gene testing results were used to differentiate patients with wild-type ATTR-CA and hereditary ATTR-CA. The transthoracic echocardiogram and electrocardiogram measurements based on the American Society of Echocardiography guidelines were included and performed around the time of the PYP scan.

In total, 155 patients underwent a PYP scan; of which 45 (29%) were PYP positive and all were wild-type ATTR-CA. In the PYP negative group, 8 (7.2%) patients had amyloid light-chain amyloidosis confirmed via biopsy. Both the PYP negative and PYP positive groups were similar in age (mean 79 years) and BMI (mean 29 kg/m2). However, the PYP negative group had a significantly higher prevalence of carpal tunnel syndrome compared with the PYP positive group (62% vs 15%, respectively; P <.01). In terms of cardiographic characteristics, patients in the PYP positive group had lower left atrial volume index (43 mL/m2 vs 59 mL/m2, respectively; P = .001), greater left ventricular septal thickness (16.7 mm vs 15 mm, respectively; P = .01), increased posterior wall thickness (15 mm vs 13 mm, respectively; P = .02) and worse diastology (2.6 ± 0.5 vs 1.7 ± 0.8, respectively; P <.001). There was no difference in ejection fraction (mean 50%) or pulmonary arterial systolic pressure (mean 38 mmHg) between groups.

“At our center, almost one-third of the hospitalized patients who were clinically suspected to have cardiac amyloidosis had a final diagnosis of wild-type ATTR-CA. A history of carpal tunnel syndrome, ECG findings of low QRS voltage, atrioventricular block and left anterior fascicular block, and echocardiographic features of left ventricular hypertrophy and high-grade diastolic dysfunction were prevalent in wild-type ATTR-CA,” reported Dr Bukhari and colleagues.

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