Coronary microvascular disease (CMD) refers to the subset of disorders affecting the structure and function of the coronary microcirculation, is prevalent in patients across a broad spectrum of ...cardiovascular risk factors, and is associated with an increased risk of adverse events. Contemporary evidence supports that most patients with CMD also have macrovessel atherosclerosis, which has important implications for their prognosis and management. In this state-of-the-art review, the authors summarize the pathophysiology of CMD, provide an update of diagnostic testing strategies, and classify CMD into phenotypes according to severity and coexistence with atherosclerosis. They examine emerging data highlighting the significance of CMD in specific populations, including obesity and insulin resistance, myocardial injury and heart failure with preserved ejection fraction, and nonobstructive and obstructive coronary artery disease. Finally, they discuss the role of CMD as a potential target for novel interventions beyond conventional approaches, representing a new frontier in cardiovascular disease reduction.
Cardiac amyloidosis, once considered untreatable, is now gaining well-deserved attention due to advances in imaging and the recent approval of targeted breakthrough therapies. In this paper, we ...discuss the role of radionuclide imaging in the evaluation and management of patients with the most common form of amyloidosis—cardiac transthyretin amyloidosis (ATTR). We provide a comprehensive summary of the literature interspersed with our institutional experience as appropriate, to deliver our perspective.
Abstract
Left ventricular (LV) hypertrophy (LVH) is a growth in left myocardial mass mainly caused by increased cardiomyocyte size. LVH can be a physiological adaptation to physical exercise or a ...pathological condition either primary, i.e. genetic, or secondary to LV overload. Patients with both primary and secondary LVH have evidence of coronary microvascular dysfunction (CMD). The latter is mainly due to capillary rarefaction and adverse remodelling of intramural coronary arterioles due to medial wall thickening with an increased wall/lumen ratio. An important feature of this phenomenon is the diffuse nature of this remodelling, which generally affects the coronary microvessels in the whole of the left ventricle. Patients with LVH secondary to arterial hypertension can develop both heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). These patients can develop HFrEF via a ‘direct pathway’ with an interval myocardial infarction and also in its absence. On the other hand, patients can develop HFpEF that can then progress to HFrEF with or without interval myocardial infarction. A similar evolution towards LV dysfunction and both HFpEF and HFrEF can occur in patients with hypertrophic cardiomyopathy, the most common genetic cardiomyopathy with a phenotype characterized by massive LVH. In this review article, we will discuss both the experimental and clinical studies explaining the mechanisms responsible for CMD in LVH as well as the evidence linking CMD with HFpEF and HFrEF.
Limited data exist on how noninvasive testing options compare for evaluating patients with suspected stable coronary artery disease. In this study, we have performed a meta-analysis of randomized ...controlled trials comparing the use of coronary computed tomographic angiography (CTA) with usual care.
We systematically searched databases for randomized clinical trials comparing coronary CTA with usual care for the evaluation of stable chest pain with follow-up for cardiovascular outcomes. The primary outcomes were myocardial infarction and all-cause mortality. We identified 4 randomized clinical trials, including a total of 7403 patients undergoing coronary CTA and 7414 patients undergoing usual care with various functional testing approaches. When compared with usual care, the use of coronary CTA was associated with a significant reduction in the annual rate of myocardial infarction (rate ratio, 0.69; 95% confidence interval, 0.49-0.98; P=0.038), but no difference was found in all-cause mortality. There was a trend toward more invasive coronary angiographies among patients undergoing coronary CTA (odds ratio, 1.33; 95% confidence interval, 0.95-1.84; P=0.09) and higher use of coronary revascularizations (odds ratio, 1.77; 95% confidence interval, 1.14-2.75). Significant heterogeneity for invasive coronary angiography and revascularization was noted, which was attributable to the Scottish Computed Tomography of the HEART (SCOT-HEART) study. We found no difference in the rate of admission for cardiac chest pain (rate ratio, 1.21; 95% confidence interval, 0.95-1.54).
In comparison to usual care, an initial investigation of suspected stable coronary artery disease using coronary CTA resulted in a significant reduction in myocardial infarction, an increased incidence of coronary revascularization, and no effect in all-cause mortality. Future studies should further define whether the potential reduction in myocardial infarction identified justifies the increased resource utilization associated with coronary CTA.
Coronary microvascular dysfunction (CMD) is a prevalent and prognostically important finding in patients with symptoms suggestive of coronary artery disease. The relative extent to which CMD affects ...both sexes is largely unknown.
We investigated 405 men and 813 women who were referred for evaluation of suspected coronary artery disease with no previous history of coronary artery disease and no visual evidence of coronary artery disease on rest/stress positron emission tomography myocardial perfusion imaging. Coronary flow reserve was quantified, and coronary flow reserve <2.0 was used to define the presence of CMD. Major adverse cardiac events, including cardiac death, nonfatal myocardial infarction, late revascularization, and hospitalization for heart failure, were assessed in a blinded fashion over a median follow-up of 1.3 years (interquartile range, 0.5-2.3 years). CMD was highly prevalent both in men and women (51% and 54%, respectively; Fisher exact test =0.39; equivalence P=0.0002). Regardless of sex, coronary flow reserve was a powerful incremental predictor of major adverse cardiac events (hazard ratio, 0.80 95% confidence interval, 0.75-086 per 10% increase in coronary flow reserve; P<0.0001) and resulted in favorable net reclassification improvement (0.280 95% confidence interval, 0.049-0.512), after adjustment for clinical risk and ventricular function. In a subgroup (n=404; 307 women/97 men) without evidence of coronary artery calcification on gated computed tomography imaging, CMD was common in both sexes, despite normal stress perfusion imaging and no coronary artery calcification (44% of men versus 48% of women; Fisher exact test P=0.56; equivalence P=0.041).
CMD is highly prevalent among at-risk individuals and is associated with adverse outcomes regardless of sex. The high prevalence of CMD in both sexes suggests that it may be a useful target for future therapeutic interventions.
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