Maternal mortality rates have been steadily increasing in the United States, and cardiovascular mortality is the leading cause of death among pregnant and postpartum women. Maternal stroke accounts for a significant burden of cardiovascular mortality. Data suggest that rates of maternal stroke have been increasing in recent years. Advancing maternal age at the time of birth and the increasing prevalence of traditional cardiovascular risk factors, and other risk factors, as well, such as hypertensive disorders of pregnancy, migraine, and infections, may contribute to increased rates of maternal stroke. In this article, we provide an overview of the epidemiology of maternal stroke, explore mechanisms that may explain increasing rates of stroke among pregnant women, and identify key knowledge gaps for future investigation in this area.
Background:
Technetium-99 m pyrophosphate protocols for transthyretin cardiac amyloidosis diagnosis have variably used 1- and 3-hour imaging time points. We investigated whether imaging at 1 hour with superior efficiency had comparable diagnostic accuracy as 3-hour imaging.
Methods:
This is a registry analysis of patients with suspected transthyretin cardiac amyloidosis referred for technetium-99 m pyrophosphate at a single tertiary center from June 2015 through January 2019. Patients underwent planar and single-photon emission computed tomography (SPECT) imaging at 1 and 3 hours. A positive Tc-99m pyrophosphate study was defined by the presence of diffuse myocardial tracer uptake on SPECT. For planar imaging, visual semiquantitative (grades 0-3, ≥2 considered positive) and quantitative heart to contralateral ratios (≥1.5 considered positive) were used.
Results:
Two hundred thirty-three patients (69% men; median age, 77 [69–83] years) underwent the study protocol. There were 60 (25.8%) patients with diffuse myocardial uptake, 1 (0.4%) with regional uptake, and 172 (73.8%) with no myocardial uptake. Results of SPECT were identical at 1 and 3 hours. Planar imaging at 1 hour had 98% sensitivity and 96% specificity. Planar grade 0 uptake or heart to contralateral ratio ≤1.2 and planar grade 3 uptake or heart to contralateral ratio ≥2.0 were always associated with negative and positive SPECT, respectively. For planar grades 1 and 2 uptake and heart to contralateral ratio 1.3 to 1.9, SPECT was needed to make a diagnosis. No patient with light-chain cardiac amyloidosis had positive SPECT.
Conclusions:
An efficient 1-hour technetium-99 m pyrophosphate protocol had comparable diagnostic performance to a 3-hour protocol.
Transthyretin and light-chain amyloidosis are the 2 main causes of cardiac amyloidosis. Recent developments in molecular imaging have transformed our ability to diagnose transthyretin cardiac amyloidosis noninvasively and unmasked a hitherto unrecognized prevalence of the disease. This review summarizes the current and evolving imaging approaches, their molecular structural basis, and the gaps in imaging capabilities that have arisen as a result of parallel developments in pharmacotherapy delivering the first effective treatment options for this condition.
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