Impaired Coronary Vascular Reactivity and Functional Capacity in Women

Insights into Myocardial Perfusion PET Imaging: the Coronary Flow Capacity

Purpose of Review

The present work summarizes the clinical relevance of coronary flow capacity (CFC) with an eye on future perspectives.

Recent findings

CFC concept has been recently introduced providing a comprehensive framework for coronary physiology evaluation.

Summary

It has been widely demonstrated that coronary artery disease (CAD) is a complex disease with a multifactorial etiology resulting from different pathogenic mechanisms. Cardiac positron emission tomography (PET) currently represents the gold standard for CAD assessment, providing absolute myocardial perfusion data including coronary flow reserve (CFR), calculated as the ratio of hyperemic to rest absolute myocardial blood flows. CFC can be obtained from dynamic PET images by plotting the primary stress perfusion data and CFR values for each pixel on a graph of predefined exact ranges. The routine evaluation of this parameter may add diagnostic and prognostic value to clinical and conventional imaging data.

Ischemia and no obstructive coronary arteries in patients with stable ischemic heart disease

A large proportion of patients with suspected obstructive coronary artery disease (CAD) is found to have ischemia with no obstructive coronary artery disease (INOCA). Based on current evidence, these patients are at increased risk of adverse cardiovascular events, even though they have no obstructive CAD. Importantly, INOCA is associated with recurrent clinical presentations with chest pain, impaired functional capacity, reduced health-related quality of life, and high healthcare costs. Underlying coronary microvascular dysfunction (CMD), through endothelium-dependent and independent mechanisms contribute to these adverse outcomes in INOCA. While non-invasive and invasive diagnostic testing has typically focused on identification of obstructive CAD in symptomatic patients, functional testing to detect coronary epicardial and microvascular dysfunction should be considered in those with INOCA who have persistent angina. Current diagnostic methods to clarify functional abnormalities and treatment strategies for epicardial and/or microvascular dysfunction in INOCA are reviewed.

Coronary atheroma burden predicts flow reserve in women with ischemia and nonobstructive coronary artery disease

Background

Women with signs and symptoms of ischemia and no obstructive coronary artery disease often have coronary microvascular dysfunction (CMD) with reduced coronary flow reserve (CFR), and compensatory coronary remodeling. Angiographic measurements of epicardial coronary anatomy (AMCA) may improve understanding of relations between CFR and atherosclerosis. We investigated AMCA and CFR in women evaluated for CMD.

Methods

Women consecutively enrolled in the Women's Ischemia Syndrome Evaluation CVD Continuation (NCT00832702) were included. All underwent clinically indicated coronary function testing measuring CFR. AMCA included coronary angiographic atheroma burden (AB), percent diameter stenosis (PDS), and tapering reference diameter Z score (RDZ), derived for the left main and left anterior descending coronary epicardial segments.

Results

The 51 women were aged 55.8 ± 10.8 years, with 19(38%) hypertensive, 10(20.4%) hyperlipidemic, 4(7.8%) diabetic, 13(25.5%) prior smokers, and mean CFR 3.0 ± 0.8. Both average and maximal AB negatively correlated with CFR (r = -0.30 and -0.31, with p = 0.04 for both), as did average and maximal PDS (r = -0.38 and -0.41 with p = 0.009 and p = 0.005) while average RDZ was directly related (r = 0.37, p = 0.01). Multiple linear regression analyses revealed that both average PDS (Units of CFR -0.03 95% CI: -0.06, -0.002, p = 0.023) and maximal PDS (-0.04 95% CI -0.07, -0.01, p = 0.007) were negatively related to CFR.

Conclusions

Measures of epicardial coronary atheroma burden, size and tapering are related to CFR, suggesting that atherosclerotic anatomical findings may contribute to or be a consequence of CMD, with further work is needed to investigate these measures as treatment targets.

Brain-heart connections in stress and cardiovascular disease: Implications for the cardiac patient

The influence of psychological stress on the physiology of the cardiovascular system, and on the etiology and outcomes of cardiovascular disease (CVD) has been the object of intense investigation. As a whole, current knowledge points to a "brain-heart axis" that is especially important in individuals with pre-existing CVD. The use of acute psychological stress provocation in the laboratory has been useful to clarify the effects of psychological stress on cardiovascular physiology, immune function, vascular reactivity, myocardial ischemia, neurobiology and cardiovascular outcomes. An emerging paradigm is that dynamic perturbations of physiological and molecular pathways during stress or negative emotions are important in influencing cardiovascular outcomes, and that some patient subgroups, such as women, patients with an early-onset myocardial infarction, and patients with adverse psychosocial exposures, may be at especially high risk for these effects. This review summarizes recent knowledge on mind-body connections in CVD among cardiac patients and highlights important pathways of risk which could become the object of future intervention efforts. As a whole, this research suggests that an integrated study of mind and body is necessary to fully understand the determinants and consequences of CVD.

Comparison of functional exercise capacity, quality of life and respiratory and peripheral muscle strength between patients with stable angina and healthy controls

Objective

We aimed to compare functional exercise capacity, respiratory and peripheral muscle strength, pulmonary function and quality of life between patients with stable angina and healthy controls.

Methods

We compared 33 patients with stable angina (55.21 ± 6.12 years old, Canada Class II–III, left ventricular ejection fraction: 61.92 ± 7.55) and 30 healthy controls (52.70 ± 4.22 years old). Functional capacity (6-minute walk test (6-MWT)), respiratory muscle strength (mouth pressure device), peripheral muscle strength (dynamometer), pulmonary function (spirometer) and quality of life (Short Form 36 (SF-36)) were evaluated.

Results

6-MWT distance (499.20 ± 51.91 m versus 633.05 ± 57.62 m), maximal inspiratory pressure (85.42 ± 20.52 cmH₂O versus 110.44 ± 32.95 cmH₂O), maximal expiratory pressure (83.33 ± 19.05 cmH₂O versus 147.96 ± 54.80 cmH₂O) and peripheral muscle strength, pulmonary function and SF-36 sub-scores were lower in the angina group versus the healthy controls, respectively.

Conclusion

Impaired peripheral and respiratory muscle strength, reduction in exercise capacity and quality of life are obvious in patients with stable angina. Therefore, these parameters should be considered in stable angina physiotherapy programmes to improve impairments.

Even "WISE-R?"-an Update on the NHLBI-Sponsored Women's Ischemia Syndrome Evaluation

PURPOSE OF REVIEW

For over 20 years, the Women's Ischemia Syndrome Evaluation (WISE), a program sponsored by the National Heart, Lung, and Blood Institute, has explored diverse and important aspects of ischemic heart disease in women.

RECENT FINDINGS

Women with symptoms and signs of ischemia but no significant epicardial obstructive coronary artery disease (INOCA) were documented to be at elevated risk for recurrent angina hospitalization, major adverse cardiac events, death, and health resource consumption rivaling those with obstructive coronary disease. WISE investigators have advanced our understanding of cardiovascular outcomes, systemic manifestations, psychological variables, socioeconomic factors, genetic contributions, hormonal status, advanced imaging, coronary functional findings, biomarkers, patient-reported outcomes, and treatments pertaining to women with this disease entity. This review delves into the WISE findings subsequent to a prior review1, postulates directions for future research, and asks are we "Even 'WISE-R?'".

Acute Coronary Syndrome: The Risk to Young Women

BACKGROUND

Although acute coronary syndrome (ACS) mainly occurs in patients >50 years, younger patients can be affected as well. We used an age cutoff of 45 years to investigate clinical characteristics and outcomes of "young" patients with ACS.

METHODS AND RESULTS

Between October 2010 and April 2016, 14 931 patients with ACS were enrolled in the ISACS-TC (International Survey of Acute Coronary Syndromes in Transitional Countries) registry. Of these patients, 1182 (8%) were aged ≤45 years (mean age, 40.3 years; 15.8% were women). The primary end point was 30-day all-cause mortality. Percentage diameter stenosis of ≤50% was defined as insignificant coronary disease. ST-segment-elevation myocardial infarction was the most common clinical manifestation of ACS in the young cases (68% versus 59.6%). Young patients had a higher incidence of insignificant coronary artery disease (11.4% versus 10.1%) and lesser extent of significant disease (single vessel, 62.7% versus 46.6%). The incidence of 30-day death was 1.3% versus 6.9% for the young and older patients, respectively. After correction for baseline and clinical differences, age ≤45 years was a predictor of survival in men (odds ratio, 0.24; 95% confidence interval, 0.10-0.58), but not in women (odds ratio, 1.35; 95% confidence interval, 0.50-3.62). This pattern of reversed risk among sexes held true after multivariable correction for in-hospital medications and reperfusion therapy. Moreover, younger women had worse outcomes than men of a similar age (odds ratio, 6.03; 95% confidence interval, 2.07-17.53).

CONCLUSION

ACS at a young age is characterized by less severe coronary disease and high prevalence of ST-segment-elevation myocardial infarction. Women have higher mortality than men. Young age is an independent predictor of lower 30-day mortality in men, but not in women.

CLINICAL TRIAL REGISTRATION

URL: http://clinicaltrials.gov/. Unique identifier: NCT01218776.

Noninvasive Imaging to Evaluate Women With Stable Ischemic Heart Disease

Declines in cardiovascular deaths have been dramatic for men but occur significantly less in women. Among patients with symptomatic ischemic heart disease (IHD), women experience relatively worse outcomes compared with their male counterparts. Evidence to date has failed to adequately explore unique female imaging targets and their correlative signs and symptoms of IHD as major determinants of IHD risk. We highlight sex-specific anatomic and functional differences in contemporary imaging and introduce imaging approaches that leverage refined targets that may improve IHD risk prediction and identify potential therapeutic strategies for symptomatic women.

Mild renal dysfunction and long-term adverse outcomes in women with chest pain: results from the National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE)

BACKGROUND

Chronic kidney disease (CKD) is associated with accelerated atherosclerosis and adverse cardiovascular outcomes, but mechanisms are unclear. We hypothesized that mild CKD independently predicts adverse outcomes in women with symptoms and signs of ischemia.

METHODS

We categorized 876 women from the Women's Ischemia Syndrome Evaluation cohort according to estimated glomerular filtration rate (eGFR) (eGFR ≥90 mL/min per 1.73 m(2) [normal], 60-89 mL/min per 1.73 m(2) [mild CKD], ≤59 mL/min per 1.73 m(2) [severe CKD]). Time to death from all-cause and cardiovascular causes and major adverse outcomes were assessed by multivariate regression adjusted for baseline covariates.

RESULTS

Obstructive coronary artery disease (CAD) was present only in few patients (39%). Even after adjusting for CAD severity, renal function remained a strong independent predictor of all-cause and cardiac mortality (P < .001). Every 10-unit decrease in eGFR was associated with a 14% increased risk of all-cause mortality (adjusted hazard ratio [AHR] 1.14 [1.08-1.20], P < .0001), 16% increased risk of cardiovascular mortality (AHR 1.16 [1.09-1.23], P < .0001), and 9% increased risk of adverse cardiovascular events (AHR 1.09 [1.03-1.15], P = .002).

CONCLUSIONS

Even mild CKD is a strong independent predictor of all-cause and cardiac mortality in women with symptoms/signs of ischemia, regardless of underlying obstructive CAD severity, underscoring the need to better understand the interactions between ischemic heart disease and CKD.

Prognostic value of estimated functional capacity incremental to cardiac biomarkers in stable cardiac patients

Background

Few studies have investigated functional capacity self‐assessment tools in either prediction of future major adverse cardiac outcomes beyond all‐cause mortality or direct comparisons with clinically available biomarkers.

Methods and Results

We estimated functional capacity using the Duke Activity Status Index (DASI) questionnaire in 8987 sequential stable patients without acute coronary syndrome who were undergoing elective diagnostic coronary angiography with 3‐year follow‐up of major adverse cardiac events (death, nonfatal myocardial infarction, or stroke). A low DASI score provided independent prediction of a 4.8‐fold increase in future risk of incident major adverse cardiac events at 3 years (quartiles 1 versus 4 hazard ratio [95% CI] 4.76 [4.03 to 5.61], P<0.001), and a 3.8‐fold increased risk after adjusting for traditional risk factors (3.77 [3.15 to 4.51], P<0.001). The prognostic value of the DASI score was evident in both primary and secondary prevention cohorts, with and without heart failure, as well as high and low C‐reactive protein and B‐type natriuretic peptide levels. The DASI score reclassified 15% of patients (P<0.001) beyond traditional risk factors in predicting future MACE.

Conclusion

A simple self‐assessment tool of functional capacity in stable patients undergoing elective diagnostic cardiac evaluation provides independent and incremental prognostic value for prediction of both significant coronary angiographic disease and long‐term adverse clinical events.

Diagnosing and characterizing coronary artery disease in women: developments in noninvasive and invasive imaging techniques

Cardiovascular disease is the leading cause of death in men and women in the USA; yet, coronary artery disease (CAD) continues to be underrecognized and underdiagnosed in women. Noninvasive and invasive imaging techniques are constantly being developed in order to more accurately assess CAD. At the same time, the impact of gender on the interpretation and accuracy of these studies is still being elucidated. Furthermore, new imaging techniques have improved our understanding of CAD pathophysiology and progression and have begun to reveal gender differences in the development of CAD. This article will review current imaging techniques and their application to diagnosing and understanding CAD in women.

Microvascular coronary dysfunction in women: pathophysiology, diagnosis, and management

Women exhibit a greater symptom burden, more functional disability, and a higher prevalence of no obstructive coronary artery disease compared to men when evaluated for signs and symptoms of myocardial ischemia. Microvascular coronary dysfunction (MCD), defined as limited coronary flow reserve and/or coronary endothelial dysfunction, is the predominant etiologic mechanism of ischemia in women with the triad of persistent chest pain, no obstructive coronary artery disease, and ischemia evidenced by stress testing. Evidence shows that approximately 50% of these patients have physiological evidence of MCD. MCD is associated with a 2.5% annual major adverse event rate that includes death, nonfatal myocardial infarction, nonfatal stroke, and congestive heart failure. Although tests such as adenosine stress cardiac magnetic resonance imaging may be a useful noninvasive method to predict subendocardial ischemia, the gold standard test to diagnose MCD is an invasive coronary reactivity testing. Early identification of MCD by coronary reactivity testing may be beneficial in prognostication and stratifying these patients for optimal medical therapy. Currently, understanding of MCD pathophysiology can be used to guide diagnosis and therapy. Continued research in MCD is needed to further advance our understanding.

Gender-related differences in coronary artery dimensions: a volumetric analysis

BACKGROUND

Women consistently have poorer revascularization outcomes and more coronary vascular complications compared to men. This has been attributed to smaller coronary arteries, though limited data exist to support this assumption.

HYPOTHESIS

By using volumetric data obtained from multidetector cardiovascular computed tomography (CCT), we sought to determine to what extent gender influences coronary artery dimensions and test the hypothesis that women would have smaller coronary dimensions even after normalizing for body surface area and cardiac mass.

METHODS

CCT examinations completed on a 64-slice scanner were identified from a university cardiovascular database. Data sets from 50 women and 44 men without coronary artery disease were selected for analysis. Cross-sectional areas of proximal and distal segments of the left anterior descending (LAD), circumflex (LCx), and right coronary artery (RCA) were measured, blinded to patient gender. Measurements were compared using 2-sample t tests and linear regression analysis techniques accounting for body surface area (BSA) and left ventricular (LV) mass.

RESULTS

Analysis of cross-sectional coronary artery areas, unadjusted for BSA and LV mass showed smaller coronary artery size in women compared to men in the proximal portion of both the LAD (P = .01) and RCA (P = .002), but no significant difference in the remaining coronary segments.

CONCLUSION

Gender significantly impacts proximal LAD and RCA size. Differences in coronary artery dimensions may explain some, but not all excess gender-related risk with coronary artery revascularization, underscoring the importance of considering multiple contributing factors.

Human studies of angiogenic gene therapy

Despite significant advances in medical, interventional, and surgical therapy for coronary and peripheral arterial disease, the burden of these illnesses remains high. To address this unmet need, the science of therapeutic angiogenesis has been evolving for almost two decades. Early preclinical studies and phase I clinical trials achieved promising results with growth factors administered as recombinant proteins or as single-agent gene therapies, and data accumulated through 10 years of clinical trials indicate that gene therapy has an acceptable safety profile. However, more rigorous phase II and phase III clinical trials have failed to unequivocally demonstrate that angiogenic agents are beneficial under the conditions and in the patients studied to date. Investigators have worked to understand the biology of the vascular system and to incorporate their findings into new treatments for patients with ischemic disease. Recent gene- and cell-therapy trials have demonstrated the bioactivity of several new agents and treatment strategies. Collectively, these observations have renewed interest in the mechanisms of angiogenesis and deepened our understanding of the complexity of vascular regeneration. Gene therapy that incorporates multiple growth factors, approaches that combine cell and gene therapy, and the administration of "master switch" agents that activate numerous downstream pathways are among the credible and plausible steps forward. In this review, we examine the clinical development of angiogenic gene therapy, summarize several of the lessons learned during the conduct of these trials, and suggest how this prior experience may guide the conduct of future preclinical investigations and clinical trials.

Launching a clinical program of stem cell therapy for cardiovascular repair

Since the feasibility of stem cell therapy has been recognized, enthusiasm for this therapy has grown exponentially. Nevertheless, as professionals we must realize that this enthusiasm should relate not only to our scientific interest but also to the care of our patients. Within the next decade, patients' demand for the latest therapies is likely to rise because of changes in health care systems that will broaden availability. Stem cell therapy is likely to be among these in-demand treatments, and we must be prepared for this change. In this Review we discuss the basic principles of how to launch a clinical program for stem cell therapy for cardiovascular repair. First, we look at the composition of the program team. Second, we describe the different types of stem cells available in clinical practice. Third, we present in depth the two most widely applicable delivery approaches. Finally, we discuss selection of patients and approaches and clinical and imaging methods by which to evaluate the safety and efficacy of this therapy.

Gender comparison of efficacy and safety of ranolazine for chronic angina pectoris in four randomized clinical trials

More women than men with myocardial infarction have previous stable angina pectoris. Women also have an increased incidence of angina after percutaneous coronary intervention and coronary artery bypass grafting. Data from 1,737 patients with stable angina pectoris in 4 international trials (Monotherapy Assessment of Ranolazine In Stable Angina [MARISA], Combination Assessment of Ranolazine In Stable Angina [CARISA], Ranolazine Versus Atenolol Comparison in Chronic Angina [RAN080], and Efficacy of Ranolazine in Chronic Angina [ERICA]) were used to compare efficacy and safety of ranolazine therapy for angina in women and men. MARISA, CARISA, and RAN080 included exercise testing; CARISA, RAN080, and ERICA assessed angina frequency and nitroglycerin consumption; and ERICA included quality-of-life assessment using the Seattle Angina Questionnaire. MARISA, CARISA, and ERICA used the extended-release formulation of ranolazine; RAN080 used ranolazine immediate release. All 4 studies showed overall efficacy and safety of ranolazine. In subgroup analyses, women showed less improvement than men in exercise testing. However, similar improvements for women and men were noted in angina frequency and nitroglycerin consumption, and in ERICA, in the angina frequency dimension of the Seattle Angina Questionnaire. In conclusion, explanations for the gender treatment differences for exercise parameters but comparable effects on decrease in angina frequency and nitroglycerin use are uncertain, but may include differences in patient demographics, reasons for stopping exercise, and type of exercise protocol used.

Ischemic Heart Disease in Women

This supplement is intended to provide a specialized forum to overview new information on the pathophysiology, diagnosis, and outcomes of women with suspected ischemic heart disease (IHD). Led by Women's Ischemic Syndrome Evaluation (WISE) study investigators and other experts, the scientific summaries contained in this supplement will permit sharing of current knowledge about this important clinical problem. Improved understanding in these areas will advance the prevention and treatment of IHD in women. These comments by the investigators and experts, as well as those from a recent National Heart, Lung, and Blood Institute consensus conference, should also provide direction for future studies in this critical area.