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Coronary microvascular dysfunction is related to abnormalities in myocardial structure and function in cardiac amyloidosis.

ABSTRACT: The purpose of this study was to test the hypothesis that coronary microvascular function is impaired in subjects with cardiac amyloidosis.Effort angina is common in subjects with cardiac amyloidosis, even in the absence of epicardial coronary artery disease (CAD).Thirty-one subjects were prospectively enrolled in this study, including 21 subjects with definite cardiac amyloidosis without epicardial CAD and 10 subjects with hypertensive left ventricular hypertrophy (LVH). All subjects underwent rest and vasodilator stress N-13 ammonia positron emission tomography and 2-dimensional echocardiography. Global left ventricular myocardial blood flow (MBF) was quantified at rest and during peak hyperemia, and coronary flow reserve (CFR) was computed (peak stress MBF/rest MBF) adjusting for rest rate pressure product.Compared with the LVH group, the amyloid group showed lower rest MBF (0.59 ± 0.15 ml/g/min vs. 0.88 ± 0.23 ml/g/min; p = 0.004), stress MBF (0.85 ± 0.29 ml/g/min vs. 1.85 ± 0.45 ml/g/min; p < 0.0001), and CFR (1.19 ± 0.38 vs. 2.23 ± 0.88; p < 0.0001) and higher minimal coronary vascular resistance (111 ± 40 ml/g/min/mm Hg vs. 70 ± 19 ml/g/min/mm Hg; p = 0.004). Of note, almost all subjects with amyloidosis (>95%) had significantly reduced peak stress MBF (<1.3 ml/g/min). In multivariable linear regression analyses, a diagnosis of amyloidosis, increased left ventricular mass, and age were the only independent predictors of impaired coronary vasodilator function.Coronary microvascular dysfunction is highly prevalent in subjects with cardiac amyloidosis, even in the absence of epicardial CAD, and may explain their anginal symptoms. Further study is required to understand whether specific therapy directed at amyloidosis may improve coronary vasomotion in amyloidosis.

SUBMITTER: Dorbala S

PROVIDER: S-EPMC4127145 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature

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Coronary microvascular dysfunction is related to abnormalities in myocardial structure and function in cardiac amyloidosis.

Dorbala Sharmila S Vangala Divya D Bruyere John J Quarta Christina C Kruger Jenna J Padera Robert R Foster Courtney C Hanley Michael M Di Carli Marcelo F MF Falk Rodney R

JACC. Heart failure 20140709 4

<h4>Objectives</h4>The purpose of this study was to test the hypothesis that coronary microvascular function is impaired in subjects with cardiac amyloidosis.<h4>Background</h4>Effort angina is common in subjects with cardiac amyloidosis, even in the absence of epicardial coronary artery disease (CAD).<h4>Methods</h4>Thirty-one subjects were prospectively enrolled in this study, including 21 subjects with definite cardiac amyloidosis without epicardial CAD and 10 subjects with hypertensive left ...[more]

PMID: 25023822

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Project description:BackgroundMicrovascular dysfunction (MVD) is a potential cause of chest pain in younger individuals. The authors hypothesized that nonelderly patients referred for computed tomographic angiography (CTA) but without significant stenosis would have a high prevalence of MVD by myocardial contrast echocardiography (MCE). Secondary aims were to test whether the presence of nonobstructive coronary artery disease (CAD) or reduced brachial flow-mediated dilation (FMD) predicted MVD.MethodsSubjects ≤60 years of age undergoing CTA were recruited if they had either no evidence of coronary plaque or evidence of mild CAD (<50% stenosis) and at least one high-risk plaque feature. Subjects underwent quantitative perfusion imaging using MCE at rest and during regadenoson vasodilator stress. MVD was defined as global or segmental delay of microvascular refill (≥2 sec) during regadenoson. FMD of the brachial artery was also performed.ResultsOf the 29 patients in whom MCE could be performed, 12 (41%) had MVD. These subjects, compared with those with normal microvascular function, had lower hyperemic perfusion (mean, 236 ± 68 vs 354 ± 161 intensity units/sec; P = .02) and microvascular flux rate (mean, 1.6 ± 0.4 vs 2.5 ± 0.9 sec-1; P = .002) on quantitative MCE. The degree of FMD was not significantly different in those with or without MVD (mean, 11 ± 4% vs 9 ± 4%; P = .32), and there was a poor correlation between results on stress MCE and FMD. Only eight of the 29 subjects were classified as having nonobstructive CAD. There were no groupwise differences in the prevalence of MVD function in those with versus without CAD (43% vs 38% for negative and positive findings on CTA, respectively, P = .79).ConclusionsMVD is a common finding in the nonelderly population referred for CTA for evaluation of possible CAD but without obstructive stenosis. Neither the presence of noncritical atherosclerotic disease nor abnormal FMD increases the likelihood for detecting MVD in this population.

Dataset Information

Coronary microvascular dysfunction is related to abnormalities in myocardial structure and function in cardiac amyloidosis.

Publications

Coronary microvascular dysfunction is related to abnormalities in myocardial structure and function in cardiac amyloidosis.

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