Coronary microvascular reactivity to adenosine predicts adverse outcome in women evaluated for suspected ischemia results from the National Heart, Lung and Blood Institute WISE (Women's Ischemia Syndrome Evaluation) study

Calculation of the index of microcirculatory resistance without coronary wedge pressure measurement in the presence of epicardial stenosis

OBJECTIVES

This study sought to investigate a novel method to calculate the index of microcirculatory resistance (IMR) in the presence of significant epicardial stenosis without the need for balloon dilation to measure the coronary wedge pressure (P(w)).

BACKGROUND

The IMR provides a quantitative measure of coronary microvasculature status. However, in the presence of significant epicardial stenosis, IMR calculation requires incorporation of the coronary fractional flow reserve (FFR(cor)), which requires balloon dilation within the coronary artery for P(w) measurement.

METHODS

A method to calculate IMR by estimating FFR(cor) from myocardial FFR (FFR(myo)), which does not require P(w) measurement, was developed from a derivation cohort of 50 patients from a single institution. This method to calculate IMR was then validated in a cohort of 72 patients from 2 other different institutions. Physiology measurements were obtained with a pressure-temperature sensor wire before coronary intervention in both cohorts.

RESULTS

From the derivation cohort, a strong linear relationship was found between FFR(cor) and FFR(myo) (FFR(cor) = 1.34 × FFR(myo) - 0.32, r(2) = 0.87, p < 0.001) by regression analysis. With this equation to estimate FFR(cor) in the validation cohort, there was no significant difference between IMR calculated from estimated FFR(cor) and measured FFR(cor) (21.2 ± 12.9 U vs. 20.4 ± 13.6 U, p = 0.161). There was good correlation (r = 0.93, p < 0.001) and agreement by Bland-Altman analysis between calculated and measured IMR.

CONCLUSIONS

The FFR(cor), and, by extension, microcirculatory resistance can be derived without the need for P(w). This method enables assessment of coronary microcirculatory status before or without balloon inflation, in the presence of epicardial stenosis.

Increased wave reflection and ejection duration in women with chest pain and nonobstructive coronary artery disease: ancillary study from the Women's Ischemia Syndrome Evaluation

OBJECTIVE

Wave reflections augment central aortic SBP and increase systolic pressure time integral (SPTI) thereby increasing left ventricular (LV) afterload and myocardial oxygen (MVO2) demand. When increased, such changes may contribute to myocardial ischemia and angina pectoris, especially when aortic diastolic time is decreased and myocardial perfusion pressure jeopardized. Accordingly, we examined pulse wave reflection characteristics and diastolic timing in a subgroup of women with chest pain (Women's Ischemia Syndrome Evaluation, WISE) and no obstructive coronary artery disease (CAD).

METHODS

Radial artery BP waveforms were recorded by applanation tonometry, and aortic BP waveforms derived. Data from WISE participants were compared with data from asymptomatic women (reference group) without chest pain matched for age, height, BMI, mean arterial BP, and heart rate.

RESULTS

Compared with the reference group, WISE participants had higher aortic SBP and pulse BP and ejection duration. These differences were associated with increased augmentation index and reflected pressure wave systolic duration. These modifications in wave reflection characteristics were associated with increased SPTI and wasted LV energy (Ew) and a decrease in pulse pressure amplification, myocardial viability ratio, and diastolic pressure time fraction.

CONCLUSION

WISE participants with no obstructive CAD have changes in systolic wave reflections and diastolic timing that increase LV afterload, MVO2 demand, and Ew with the potential to reduce coronary artery perfusion. These alterations in cardiovascular function contribute to an undesirable mismatch in the MVO2 supply/demand that promotes ischemia and chest pain and may contribute to, or increase the severity of, future adverse cardiovascular events.

Adverse outcomes among women presenting with signs and symptoms of ischemia and no obstructive coronary artery disease: findings from the National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE) angiographic core laboratory

BACKGROUND

Women presenting with signs and symptoms of myocardial ischemia frequently have no or nonobstructive coronary artery disease (CAD).

OBJECTIVE

This study aimed to investigate the associations between angiographic measures and longer-term clinical outcomes among women with signs and symptoms of ischemia referred for coronary angiography.

METHODS

A prospective cohort analysis of women referred for coronary angiography and enrolled in the National Heart, Lung, and Blood Institute-sponsored WISE was performed. An angiographic severity score was prospectively developed, assigning points for any stenosis weighted by stenosis severity, location, and collaterals and was then tested for prediction for adverse outcome in 917 women, over a median of 9.3 years.

SETTING

The study was conducted in referral centers.

PATIENTS

Women with signs and/or symptoms of myocardial ischemia referred for coronary angiography were consecutively consented and enrolled in a prospective study.

MAIN OUTCOME MEASURES

Main outcomes included first occurrence of cardiovascular death or nonfatal myocardial infarction. Hospitalization for angina was a secondary outcome.

RESULTS

Cardiovascular death or myocardial infarction at 10 years occurred in 6.7%, 12.8%, and 25.9% of women with no, nonobstructive, and obstructive CAD (P < .0001), respectively. Cumulative 10-year cardiovascular death or myocardial infarction rates showed progressive, near-linear increases for each WISE CAD severity score range of 5, 5.1 to 10, 10.1 to 20, 20.1 to 50, and >50. The optimal threshold in the WISE severity score classifications for predicting cardiovascular mortality was >10 (eg, 5.0-10 vs 10.1-89), with both a sensitivity and specificity of 0.64 and an area under the curve of 0.64 (P = .02, 95% CI 0.59-0.68).

CONCLUSIONS

Among women with signs and symptoms of ischemia, nonobstructive CAD is common and associated with adverse outcomes over the longer term. The new WISE angiographic score appears to be useful for risk prediction in this population.

Evolving strategies for the treatment of microvascular angina in women

Microvascular angina, also known as cardiac syndrome X, is characterized by anginal chest pain, at least one cardiovascular risk factor, an abnormal stress test and normal coronary arteries on angiography. It is significantly more common in women than in men. A definitive diagnosis of microvascular angina can be made by invasive or noninvasive methods; a presumptive diagnosis can also be made based on fulfillment of diagnostic criteria. Effective treatment of microvascular angina requires aggressive risk factor modification; exercise is one of the most effective treatment modalities. Several other treatment strategies have been shown to relieve anginal symptoms as well as improve vascular function; these include β-blockers, angiotensin-converting enzyme inhibitors, ranolazine, L-arginine, statin drugs and potentially estrogen replacement therapy. Nitrates may be effective for symptom relief. Further studies are required to determine whether specific treatments are associated with improved survival as well as decreased symptoms.

Gender disparity in cardiovascular disease: bias or biology?

This article addresses gender disparity in cardiovascular disease, with selected examples used to explore whether these disparities represent bias, biology or both. Gender-specific basic and clinical cardiovascular research is needed to address these issues, with rigorous application required for the emerging knowledge. These explorations offer promise to improve cardiovascular outcomes for women and are the basis for the application of gender-based evaluation of pathophysiology, clinical presentations, preventive interventions, diagnostic strategies, therapies and outcomes of cardiovascular disease in women.

Persistent angina: highly prevalent and associated with long-term anxiety, depression, low physical functioning, and quality of life in stable angina pectoris

AIMS

To evaluate persistent angina in stable angina pectoris with no obstructive coronary artery disease (CAD) compared to obstructive CAD and its relation to long-term anxiety, depression, quality of life (QOL), and physical functioning.

METHODS AND RESULTS

We invited 357 patients (men = 191; women = 166; response rate 83 %) with no prior cardiovascular disease who had a first-time coronary angiography (CAG) in 2008-2009 due to suspected stable angina to participate in a questionnaire survey in 2011 with the Seattle Angina Questionnaire and the Hospital Anxiety and Depression Scale as key elements. Long-term persistent angina (i.e., symptoms at least once a month) was present in 64 % of patients with diffuse non-obstructive CAD (1-49 % stenosis), 49 % of patients with normal coronary arteries (0 % stenosis), and 41 % of patients with obstructive CAD (≥ 50 % stenosis) (P = 0.01). Depression and anxiety were more common in patients with persistent angina: 24 versus 7 % (P < 0.001) reported HADS-Depression-scores >7 and 42 versus 21 % (P < 0.001) reported HADS-Anxiety-scores >7. In multivariate regression models, persistent angina was associated with depression (OR 4.3, 95 % confidence interval (CI) 1.9-9.6, P < 0.001), anxiety (OR 2.9, 95 % CI 1.6-5.1, P < 0.001), the severity of persistent angina with impaired physical functioning (P < 0.001), and QOL (P < 0.001); whereas outcomes were not related to age, gender, or degree of CAD.

CONCLUSIONS

The study indicates higher prevalence of persistent angina in patients with diffuse non-obstructive CAD or normal coronary arteries than in patients with obstructive CAD. Persistent angina symptoms were associated with long-term anxiety, depression, impaired physical functioning, and QOL irrespective of the degree of CAD. Contrary to common perception, excluding obstructive CAD in stable angina does not ensure a favorable disease course, and further risk stratification and treatment strategies are warranted.

Gender differences in the pathophysiology, clinical presentation, and outcomes of ischemic heart failure

Despite advances in the treatment of acute myocardial infarction (MI), heart failure (HF) remains a frequent acute and long-term outcome of ischemic heart disease (IHD). In response to acute coronary ischemia, women are relatively protected from apoptosis, and experience less adverse cardiac remodeling than men, frequently resulting in preservation of left ventricular size and ejection fraction. Despite these advantages, women are at increased risk for HF- complicating acute MI when compared with men. However, women with HF retain a survival advantage over men with HF, including a decreased risk of sudden death. Sex-specific treatment of HF has been hindered by historical under-representation of women in clinical trials, though recent work has suggested that women may have a differential response to some therapies such as cardiac resynchronization. This review highlights the sex differences in the pathophysiology, clinical presentation and outcomes of ischemic heart failure and discusses key areas worthy of further investigation.

Elevated C1rC1sC1inh levels independently predict atherosclerotic coronary heart disease

Clinical studies as well as animal models emphasized the importance of the complement system in the pathogenesis of coronary atherosclerosis and cardiovascular diseases. Our aim was to examine the extent and clinical implication of complement system activation in patients with stable atherosclerotic coronary heart disease (ACHD). Seventy-six patients with stable angina pectoris (SAP) scheduled for elective coronary angiography were enrolled into the study. Percutaneous coronary intervention (PCI) was performed in 24 patients, in 27 patients (NOPCI group) the coronary angiography showed significant stenosis and bypass surgery (CABG) or optimal medical therapy (OMT) were advised, whereas in 25 patients the coronary angiography was negative (NC group). 115 volunteers served as healthy controls (HC). In all individuals, the plasma level of several complement activation products - C1rC1sC1inh, C3bBbP and SC5b-9 - were determined on admission, strictly before the coronary angiography. In patients with angiographically proven ACHD (PCI and NOPCI groups), the baseline C1rC1sC1inh levels were significantly higher compared to NC group and HC (p<0.0001, for both comparisons). According to the multiple logistic regression analysis, high C1rC1sC1inh level proved to be an independent biomarker of coronary heart disease (p<0.026, OR: 65.3, CI: 1.628-2616.284).

CONCLUSION

Activation of the classical complement pathway can be observed in angiographically proven coronary atherosclerosis. Elevated C1rC1sC1inh levels might represent an useful biomarker for coronary artery disease.

Microvascular coronary artery spasm presents distinctive clinical features with endothelial dysfunction as nonobstructive coronary artery disease

Background

Angina without significant stenosis, or nonobstructive coronary artery disease, attracts clinical attention. Microvascular coronary artery spasm (microvascular CAS) can cause nonobstructive coronary artery disease. We investigated the clinical features of microvascular CAS and the therapeutic efficacy of calcium channel blockers.

Methods and Results

Three hundred seventy consecutive, stable patients with suspected angina presenting nonobstructive coronary arteries (<50% diameter) in coronary angiography were investigated with the intracoronary acetylcholine provocation test, with simultaneous measurements of transcardiac lactate production and of changes in the quantitative coronary blood flow. We diagnosed microvascular CAS according to lactate production and a decrease in coronary blood flow without epicardial vasospasm during the acetylcholine provocation test. We prospectively followed up the patients with calcium channel blockers for microvascular coronary artery disease. We identified 50 patients with microvascular CAS who demonstrated significant impairment of the endothelium-dependent vascular response, which was assessed by coronary blood flow during the acetylcholine provocation test. Administration of isosorbide dinitrate normalized the abnormal coronary flow pattern in the patients with microvascular CAS. Multivariate logistic regression analysis indicated that female sex, a lower body mass index, minor–borderline ischemic electrocardiogram findings at rest, limited–baseline diastolic-to-systolic velocity ratio, and attenuated adenosine triphosphate–induced coronary flow reserve were independently correlated with the presence of microvascular CAS. Receiver-operating characteristics curve analysis revealed that the aforementioned 5-variable model showed good correlation with the presence of microvascular CAS (area under the curve: 0.820). No patients with microvascular CAS treated with calcium channel blockers developed cardiovascular events over 47.8±27.5 months.

Conclusions

Microvascular CAS causes distinctive clinical features and endothelial dysfunction that are important to recognize as nonobstructive coronary artery disease so that optimal care with calcium channel blockers can be provided.

Clinical Trial Registration

URL: www.umin.ac.jp/ctr. Unique identifier: UMIN000003839.

Coronary microvascular dysfunction in the clinical setting: from mystery to reality

Far more extensive than the epicardial coronary vasculature that can be visualized angiographically is the coronary microcirculation, which foregoes routine imaging. Probably due to the lack of techniques able to provide tangible evidence of its crucial role, the clinical importance of coronary microvascular dysfunction is not fully appreciated. However, evidence gathered over the last several decades indicates that both functional and structural abnormalities of the coronary microvasculature can lead to myocardial ischaemia, often comparable with that caused by obstructive coronary artery disease. Indeed, a marked increase in coronary microvascular resistance can impair coronary blood flow and trigger angina pectoris, ischaemic ECG shifts, and myocardial perfusion defects, and lead to left ventricular dysfunction in patients who otherwise have patent epicardial coronary arteries. This condition--often referred to as 'chest pain with normal coronary arteries' or 'cardiac syndrome X'--encompasses several pathogenic mechanisms involving the coronary microcirculation. Of importance, coronary microvascular dysfunction can occur in conjunction with several other cardiac disease processes. In this article, we review the pathogenic mechanisms leading to coronary microvascular dysfunction and its diagnostic assessment, as well as the different clinical presentations and prognostic implications of microvascular angina. As such, this review aims to remove at least some of the mystery surrounding the notion of coronary microvascular dysfunction and to show why it represents a true clinical entity.

Cardiac syndrome X and microvascular coronary dysfunction

Women with cardiac chest pain indicated by signs and symptoms of myocardial ischemia in the absence of obstructive CAD are often labelled as cardiac syndrome X (CSX). A subset of patients with CSX may have symptoms of ischemia due to microvascular dysfunction. Angina due to microvascular coronary dysfunction (MCD) is an etiologic mechanism in women with vascular dysfunction. New data provide improve understanding of coronary vascular dysfunction and resultant myocardial ischemia that characterize MCD among patients with cardiac syndrome X. MCD has an adverse prognosis and health care cost expenditure comparable to obstructive CAD. The high prevalence of this condition, particularly in women, adverse prognosis and substantial health care costs, coupled with a lack of evidence regarding treatment strategies, places MCD as a research priority area.

Coronary microvascular function and cortical pain processing in patients with silent positive exercise testing and normal coronary arteries

ST-segment depression during exercise stress testing in asymptomatic subjects showing normal coronary arteries is considered a "false-positive" result. Coronary microvascular dysfunction, however, might be a possible cause of ST-segment depression in these cases. We assessed the coronary blood flow response to adenosine and to cold pressor test in the left anterior descending artery, using transthoracic Doppler echocardiography in 14 asymptomatic subjects with exercise-induced ST-segment depression and normal coronary arteries (group 1), 14 patients with microvascular angina (group 2), and 14 healthy subjects (group 3). Flow-mediated dilation was assessed in the brachial artery. Central pain processing was assessed using cortical laser evoked potentials during chest and right hand stimulation with 3 sequences of painful stimuli. The coronary blood flow response to adenosine was 1.8 ± 0.4, 1.9 ± 0.5, and 3.1 ± 0.9 in groups 1, 2, and 3, respectively (p <0.001). The corresponding coronary blood flow responses to the cold pressor test were 1.74 ± 0.4, 1.53 ± 0.3, and 2.3 ± 0.6 (p <0.001). The flow-mediated dilation was 5.5 ± 2.3%, 4.6 ± 2.4%, and 9.8 ± 1.2% in the 3 groups, respectively (p <0.001). The laser evoked potential N2/P2 wave amplitude decreased throughout the 3 sequences of stimulation in groups 1 and 3 but not in group 2 (chest, -19 ± 22%, +11 ± 42% and -36 ± 12%, p <0.001; right hand, -22 ± 25%, +12 ± 43% and -30 ± 20%, p = 0.009; in groups 1, 2, and 3). In conclusion, exercise stress test-induced ST-segment depression in asymptomatic subjects with normal coronary arteries cannot be considered as a simple false-positive result, because it can be related to coronary microvascular dysfunction. The different symptomatic state compared to patients with microvascular angina can, at least in part, be explained by differences in cortical processing of neural pain stimuli.

Safety of coronary reactivity testing in women with no obstructive coronary artery disease: results from the NHLBI-sponsored WISE (Women's Ischemia Syndrome Evaluation) study

OBJECTIVES

This study evaluated the safety of coronary reactivity testing (CRT) in symptomatic women with evidence of myocardial ischemia and no obstructive coronary artery disease (CAD).

BACKGROUND

Microvascular coronary dysfunction (MCD) in women with no obstructive CAD portends an adverse prognosis of a 2.5% annual major adverse cardiovascular event (MACE) rate. The diagnosis of MCD is established by invasive CRT, yet the risk of CRT is unknown.

METHODS

The authors evaluated 293 symptomatic women with ischemia and no obstructive CAD, who underwent CRT at 3 experienced centers. Microvascular function was assessed using a Doppler wire and injections of adenosine, acetylcholine, and nitroglycerin into the left coronary artery. CRT-related serious adverse events (SAEs), adverse events (AEs), and follow-up MACE (death, nonfatal myocardial infarction [MI], nonfatal stroke, or hospitalization for heart failure) were recorded.

RESULTS

CRT-SAEs occurred in 2 women (0.7%) during the procedure: 1 had coronary artery dissection, and 1 developed MI associated with coronary spasm. CRT-AEs occurred in 2 women (0.7%) and included 1 transient air microembolism and 1 deep venous thrombosis. There was no CRT-related mortality. In the mean follow-up period of 5.4 years, the MACE rate was 8.2%, including 5 deaths (1.7%), 8 nonfatal MIs (2.7%), 8 nonfatal strokes (2.7%), and 11 hospitalizations for heart failure (3.8%).

CONCLUSIONS

In women undergoing CRT for suspected MCD, contemporary testing carries a relatively low risk compared with the MACE rate in these women. These results support the use of CRT by experienced operators for establishing definitive diagnosis and assessing prognosis in this at-risk population. (Women's Ischemia Syndrome Evaluation [WISE]; NCT00832702).

Recurrent angina after coronary angioplasty: mechanisms, diagnostic and therapeutic options

Recurrent angina in patients who underwent percutaneous coronary intervention is defined as recurrence of chest pain or chest discomfort. Careful assessment is recommended to differentiate between non-cardiac and cardiac causes. In the case of the latter, recurrent angina occurrence can be related to structural ('stretch pain', in-stent restenosis, in-stent thrombosis, incomplete revascularization, progression of coronary atherosclerosis) or functional (coronary micro-vascular dysfunction, epicardial coronary spasm) causes. Even though a complete diagnostic algorithm has not been validated, ECG exercise testing, stress imaging and invasive assessment of coronary blood flow and coronary vaso-motion (i.e. coronary flow reserve, provocation testing for coronary spasm) may be required. When repeated coronary revascularization is not indicated, therapeutic approaches should aim at targeting the underlying mechanism for the patient's symptoms using a variety of drugs currently available such as beta-blockers, calcium-channel blockers, ivabradine or ranolazine.

Reduced survival in patients with "coronary microvascular disease"

The syndrome of chest pain, abnormal stress test, and nonflow limiting coronary artery disease (CAD) is common and is attributed to coronary microvascular disease (µVD). It is associated with increased hospital admissions and health care costs. But its impact on long-term survival is not known. Of the 9941 consecutive patients who had an exercise stress test for evaluation of chest pain between May 1991 and July 2007, 935 had both a positive stress test and a coronary angiogram within 1 year of their stress test forming the study cohort. Significant angiographic CAD defined as ≥70% stenosis of an epicardial coronary artery or ≥50% stenosis of the left main coronary artery was present in 324 patients. Rest (n = 611) were considered to have coronary µVD. Compared with patients with significant epicardial CAD, patients with coronary µVD were younger (63 ± 11 vs. 65 ± 10 years, p = 0.002), and had lower left ventricular wall thickness (p < 0.02), systolic blood pressure (BP; p = 0.002), pulse pressure (0.0008), systolic BP with exercise (p = 0.0001), and pulse pressure with exercise (p < 0.0001). Those with coronary µVD had a better survival compared with those with significant epicardial CAD, but worse than that expected for age- and gender-matched population (p < 0.0001). Coronary µVD as a cause of chest pain and positive stress test is common. All-cause mortality in patients with coronary µVD is worse than in an age- and gender-matched population control, but better than those with significant epicardial CAD.

Safety and efficacy of intracoronary adenosine administration in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention: a meta-analysis of randomized controlled trials

Background: Studies evaluating intracoronary administration of adenosine for prevention of microvascular dysfunction and ischemic-reperfusion injury in patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI) have yielded mixed results. Therefore, we performed a meta-analysis of these trials to evaluate the safety and efficacy of intracoronary adenosine administration in patients with AMI undergoing primary PCI.

Methods: A total of seven prospective randomized controlled trials were analyzed. The endpoints extracted were post-procedure residual stent thrombosis (ST) segment elevation and ST segment resolutions (STRes), difference in peak creatine kinase (CK-MB) concentration, thrombolysis in myocardial infarction (TIMI) grade III flow (TIMI 3 flow), myocardial blush grade (MBG) 3, mean difference in post-PCI ejection fraction (EF), all-cause mortality, cardiovascular mortality, heart failure (HF) and major adverse cardiovascular event (MACE). Safety endpoints analyzed were bradycardia, second-degree atrioventricular block (AVB), ventricular tachycardia (VT), ventricular fibrillation (VF) and recurrence of chest pain (CP). The endpoints were analyzed by standard methods of meta-analysis.

Results: Intracoronary adenosine therapy led to significantly more post-PCI STRes [relative risk (RR) 1.39, 95% confidence interval (CI) 1.01–1.90; p = 0.04] and reduction in residual ST segment elevation (RR 0.82, CI 0.69–0.99; p = 0.04) but did not improve TIMI 3 flow (RR 1.09, CI 0.94–1.27; p = 0.25), MBG3 (RR 1.04, CI 0.65–1.69; p = 0.88), peak CK-MB concentration (mean difference −39.43, CI −120.223 to 41.371; p = 0.339) and post-PCI EF (mean difference 1.238, CI −5.802 to 8.277; p = 0.730). There was a trend towards improvement and MACE (RR 0.64, CI 0.40–1.03; p = 0.06), incidence of HF (RR 0.47, CI 0.19–1.12; p = 0.08) and CV mortality (RR 0.15, CI 0.02–1.23; p = 0.08) that did not reach statistical significance but no difference in all-cause mortality (RR 0.77, CI 0.25–2.34; p = 0.64). Safety analysis showed no significant difference in CP events (RR 1.26, CI 0.55–2.86; p = 0.58), bradycardia (RR 2.19, CI 0.24–0.38; p = 0.49), VT (odds ratio 0.61, CI 0.08–4.90; p = 0.64) and VF (RR 0.49, CI 0.13–1.90; p = 0.30), but significantly more second-degree AVB (RR 7.88, CI 4.15–14.9; p < 0.01) in the adenosine group compared with the placebo group.

Conclusion: Intracoronary adenosine administration was well tolerated and significantly improved electrocardiographic outcomes with a tendency towards improvement in MACE, HF and CV mortality that could not reach statistical significance.

High prevalence of a pathological response to acetylcholine testing in patients with stable angina pectoris and unobstructed coronary arteries. The ACOVA Study (Abnormal COronary VAsomotion in patients with stable angina and unobstructed coronary arteries)

OBJECTIVES

This study aimed at determining the prevalence of epicardial and microvascular coronary spasm in patients with anginal symptoms, despite angiographically normal coronary arteries.

BACKGROUND

Despite a typical clinical presentation with exercise-related anginal symptoms (chest pain or dyspnea) with or without occasional attacks of resting chest pain suggestive of coronary artery disease, 40% of patients undergoing diagnostic angiography have normal or "near" normal coronary arteriograms. Many of these patients are given a diagnosis of noncardiac chest pain, and some are considered to have microvascular angina. However, we speculate that abnormal coronary vasomotion (reduced vasodilatation with exercise = reduced coronary flow reserve and/or vasospasm at rest) might also represent a plausible explanation for the symptoms of the patient.

METHODS

This was a prospective study in 304 consecutive patients (50% men, mean age 66 ± 10 years) with exertional anginal symptoms undergoing diagnostic angiography. A total of 139 patients (46%) had ≥50% coronary artery disease in at least 1 coronary artery, 21 patients (7%) had luminal narrowings ranging from >20% to 49%, and 144 patients (47%) had normal coronary arteries or only minimal irregularities (<20% diameter reduction).

RESULTS

One hundred twenty-four patients of the latter (86%) underwent intracoronary acetylcholine (ACH) testing, which elicited coronary spasm in 77 patients (62%), 35 patients (45%) with epicardial spasm (≥75% diameter reduction with reproduction of the symptoms of the patient) and 42 patients (55%) with microvascular spasm (reproduction of symptoms, ischemic electrocardiographic changes, and no epicardial spasm).

CONCLUSIONS

Nearly 50% of patients undergoing diagnostic angiography for assessment of stable angina had angiographically normal or near normal coronary arteriograms. The ACH test triggered epicardial or microvascular coronary spasm in nearly two-thirds of these patients. Our results suggest that abnormal coronary vasomotion plays a pathogenic role in this setting and that the ACH test might be useful to identify patients with cardiac symptoms, despite normal coronaries. (Abnormal Coronary Vasomotion in Patients With Suspected CAD But Normal Coronary Arteries; NCT00921856).

Coronary microcirculatory resistance is independent of epicardial stenosis

BACKGROUND

Recent studies show that coronary microcirculatory impairment is an independent predictor of poor outcomes in patients with cardiovascular disease. However, controversy exists over whether microcirculatory resistance, a measure of coronary microcirculatory status, is dependent on epicardial stenosis severity. Previous studies demonstrating that microcirculatory resistance is dependent on epicardial stenosis severity have not accounted for collateral flow in their measurement of microcirculatory resistance. We investigated whether the index of microcirculatory resistance is independent of epicardial stenosis by comparing the index of microcirculatory resistance (IMR) levels in patients before and after percutaneous coronary intervention (PCI).

METHODS AND RESULTS

Consecutive patients undergoing elective PCI of the left anterior descending artery were recruited. Patients who developed periprocedural myocardial infarction were excluded. A pressure-temperature sensor wire was used to measure the apparent IMR (IMR(app)), which does not adjust for collateral flow, and the true IMR (IMR(true)), which incorporates wedge pressure measurement to account for collateral flow, before and after PCI. In 43 patients, there was no difference between pre- and post-PCI IMR(true) (mean difference=0.8±11.7, P=0.675). IMR(app) was higher pre-PCI compared with post-PCI (mean difference=10.0±14.5, P<0.001). IMR(app) was higher than IMR(true) (mean difference=9.3±14.2, P<0.001), and the difference between the IMR(app) and IMR(true) became greater with decreasing fractional flow reserve and increasing coronary wedge pressure. Pre-PCI fractional flow reserve correlated modestly with IMR(app) (r=-0.33, P=0.03), but not IMR(true) (r=0.26, P=0.10).

CONCLUSIONS

Coronary microcirculatory resistance is independent of functional epicardial stenosis severity when collateral flow is taken into account.

Contrast stress echocardiography in hypertensive heart disease

Hypertension is associated with atherosclerosis and cardiac and vascular structural and functional changes. Myocardial ischemia may arise in hypertension independent of coronary artery disease through an interaction between several pathophysiological mechanisms, including left ventricular hypertrophy, increased arterial stiffness and reduced coronary flow reserve associated with microvascular disease and endothelial dysfunction. The present case report demonstrates how contrast stress echocardiography can be used to diagnose myocardial ischemia in a hypertensive patient with angina pectoris but without significant obstructive coronary artery disease. The myocardial ischemia was due to severe resistant hypertension complicated with concentric left ventricular hypertrophy and increased arterial stiffness.

In women with symptoms of cardiac ischemia, nonobstructive coronary arteries, and microvascular dysfunction, angiotensin-converting enzyme inhibition is associated with improved microvascular function: A double-blind randomized study from the National Heart, Lung and Blood Institute Women's Ischemia Syndrome Evaluation (WISE)

BACKGROUND

We investigated the role of the renin-angiotensin system in women with signs and symptoms of ischemia without obstructive coronary artery disease (CAD). Although microvascular dysfunction has been suggested to explain this syndrome and recently was found to predict adverse outcomes, the mechanisms and treatments remain unclear.

METHODS

In a substudy within the WISE, 78 women with microvascular dysfunction (coronary flow reserve [CFR] <3.0 following adenosine) and no obstructive CAD were randomly assigned to either an angiotensin-converting enzyme inhibition (ACE-I) with quinapril or a placebo treatment group. The primary efficacy parameter was CFR at 16 weeks adjusted for baseline characteristics and clinical site. The secondary response variable was freedom from angina symptoms assessed using the Seattle Angina Questionnaire.

RESULTS

A total of 61 women completed the 16-week treatment period with repeat CFR measurements, and treatment was well tolerated. For the primary outcome, at 16 weeks, CFR improved more with ACE-I than placebo (P < .02). For the secondary outcome of symptom improvement, ACE-I treatment (P = .037) and CFR increase (P = .008) both contributed.

CONCLUSIONS

Microvascular function improves with ACE-I therapy in women with signs and symptoms of ischemia without obstructive CAD. This improvement is associated with reduction in angina. The beneficial response of the coronary microvasculature was limited to women with lower baseline CFR values, suggesting that the renin-angiotensin system may be more involved among women with more severe microvascular defects.

Stable angina pectoris with no obstructive coronary artery disease is associated with increased risks of major adverse cardiovascular events

AIMS

Patients with chest pain and no obstructive coronary artery disease (CAD) are considered at low risk for cardiovascular events but evidence supporting this is scarce. We investigated the prognostic implications of stable angina pectoris in relation to the presence and degree of CAD with no obstructive CAD in focus.

METHODS AND RESULTS

We identified 11 223 patients referred for coronary angiography (CAG) in 1998-2009 with stable angina pectoris as indication and 5705 participants from the Copenhagen City Heart Study for comparison. Main outcome measures were major adverse cardiovascular events (MACE), defined as cardiovascular death, myocardial infarction, stroke or heart failure, and all-cause mortality. Significantly more women (65%) than men (32%) had no obstructive CAD (P< 0.001). In Cox's models adjusted for age, body mass index, diabetes, smoking, and use of lipid-lowering or antihypertensive medication, hazard ratios (HRs) associated with no obstructive CAD were similar in men and women. In the pooled analysis, the risk of MACE increased with increasing degrees of CAD with multivariable-adjusted HRs of 1.52 (95% confidence interval, 1.27-1.83) for patients with normal coronary arteries and 1.85 (1.51-2.28) for patients with diffuse non-obstructive CAD compared with the reference population. For all-cause mortality, normal coronary arteries and diffuse non-obstructive CAD were associated with HRs of 1.29 (1.07-1.56) and 1.52 (1.24-1.88), respectively.

CONCLUSION

Patients with stable angina and normal coronary arteries or diffuse non-obstructive CAD have elevated risks of MACE and all-cause mortality compared with a reference population without ischaemic heart disease.

Interleukin 17 as a novel predictor of vascular function in rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is associated with enhanced cardiovascular (CV) risk and subclinical vascular disease. The proinflammatory milieu has been linked to premature atherosclerosis and endothelial dysfunction in RA. While interleukin 17 (IL-17) is considered pathogenic in RA, its role in determining vascular dysfunction in this disease has not been systematically assessed.

OBJECTIVES

To analyse candidate variables that might determine endothelial function in various vascular territories in a cohort of patients with RA receiving treatment with biological agents, with minimal traditional CV risk factors and low disease activity score.

METHODS

Patients with RA (n=50) receiving stable treatment with biological agents underwent measurement of conduit artery endothelial function by brachial artery flow-mediated dilatation; arterial compliance by pulse wave velocity (PWV) assessment; and endothelium-dependent microvascular testing with Endo-Pat2000 device to assess the reactive hyperaemia index (RHI). IL-17 was quantified by ELISA and disease activity was assessed by 28-joint count Disease Activity Score.

RESULTS

IL-17 was the main determinant of lower RHI in univariate and multivariate analysis. Traditional and non-traditional CV risk variables determined PWV, with a significant positive association with IL-17 in univariate and multivariate analysis. In contrast, conduit endothelial function was mainly determined by rheumatoid factor titres in univariate and multivariate analysis. Anti-cyclic citrullinated peptide titres, specific disease-modifying antirheumatic drugs or biological agents and disease activity did not determine vascular function.

CONCLUSION

In patients with RA treated with biological agents, IL-17 is a main predictor of microvascular function and arterial compliance. This study suggests that IL-17 may play a significant role in development of endothelial dysfunction and cardiovascular disease in RA.

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.

Effect of phosphodiesterase type 5 inhibition on microvascular coronary dysfunction in women: a Women's Ischemia Syndrome Evaluation (WISE) ancillary study

BACKGROUND

Microvascular coronary dysfunction (MCD) is associated with symptoms and signs of ischemia, and also adverse outcomes in women without macrovascular obstructive coronary artery disease (M-CAD). Although MCD can be quantified using coronary flow reserve (CFR), treatment is poorly defined.

HYPOTHESIS

Phosphodiesterase type 5 (PDE-5) inhibition acutely improves MCD in these women.

METHODS

The subjects were 23 symptomatic women (age 54 ± 11 y) participating in an ancillary study of the Women's Ischemia Syndrome Evaluation with baseline CFR ≤3.0 (Doppler flow wire and intracoronary adenosine) and without M-CAD. Coronary flow reserve was remeasured 45 minutes after PDE-5 inhibition (100 mg oral sildenafil). The primary measure of interest was change in CFR adjusted for baseline variables.

RESULTS

The relationship between log(2)-transformed CFR post-PDE-5 inhibition (adjusted) and baseline was different from the line of identity (slope: 0.55 vs 1.0, P = 0.008; intercept: 0.73 vs 0.0, P = 0.01), indicating that PDE-5 inhibition improves CFR and the lower the baseline CFR, the greater the response. Among women with baseline CFR ≤2.5 (n = 11), CFR increased from 2.1 ± 0.2 to 2.7 ± 0.6 (P = 0.006). For women with baseline CFR >2.5 (n = 12), CFR did not change (3.1 ± 0.3 to 3.0 ± 0.6; P = 0.70).

CONCLUSIONS

For women with symptoms and signs of ischemia and no M-CAD, PDE-5 inhibition is associated with acute improvement in CFR, and the effect concentrates among those with CFR ≤2.5. If these acute effects are sustained, then PDE-5 inhibition would provide a rational strategy for management of MCD in symptomatic women without M-CAD. The longer-term effects warrant study in a randomized trial using a sustained-acting PDE-5 inhibitor.

Microvascular angina: assessment of coronary blood flow, flow reserve, and metabolism

Microvascular angina (MVA) is an often overlooked cause of significant chest pain. Decreased myocardial perfusion secondary to dysregulated blood flow in the microvasculature can occur in the presence or absence of obstructive epicardial coronary artery disease. The corresponding myocardial ischemia and angina is now a well-established diagnosis, made by detection of decreased coronary flow reserve (CFR). Although low CFR and MVA are associated with poor prognosis, there is initial evidence for reversibility of this abnormal vascular regulation with aggressive medical therapy and control of associated risk factors. Current assessment of MVA is carried out predominantly during cardiac catheterization; however, noninvasive techniques to assess CFR are being developed, including PET, MRI, and CT modalities. Quantitative tracer techniques or imaging of metabolic disturbances reflecting ischemia will likely enhance diagnostic approaches for such patients as well as allow more frequent monitoring of response to therapy.

The role of plasma aminothiols in the prediction of coronary microvascular dysfunction and plaque vulnerability

BACKGROUND

Although oxidative stress is considered a key pathogenic step in mediating vascular dysfunction and atherosclerosis development, their association has not been evaluated in human coronary circulation in vivo. Accordingly, we hypothesized that higher oxidative stress would be associated with abnormal coronary epicardial structure and microvascular function.

METHODS

We measured coronary flow velocity reserve (CFVR) and hyperemic microvascular resistance (HMR) as indices of microvascular function, and epicardial plaque volume and necrotic core using intravascular ultrasound (IVUS) in 47 patients undergoing cardiac catheterization. Plasma glutathione, cystine and their ratio served as measures of oxidative stress while high-sensitivity C-reactive protein (hs-CRP) served as a measure of inflammation.

RESULTS

Lower glutathione, a measure of increased oxidative stress was associated with impaired microvascular function [CFVR (r=0.39, p=0.01) and HMR (r=-0.43, p=0.004)], greater plaque burden (r=-0.32, p=0.03) and necrotic core (r=-0.39, p=0.008). Similarly, higher cystine/glutathione ratio was associated with impaired microvascular function [CFVR (r=-0.29, p=0.04)] and greater necrotic core (r=0.37, p=0.01). In comparison, higher hs-CRP was associated only with greater necrotic core (r=0.45, p=0.003). After multivariate adjustment for age, gender, hypertension, diabetes, acute coronary syndrome presentation, body mass index, tobacco abuse, statin use and hs-CRP, glutathione remained an independent predictor of CFVR, HMR and necrotic core (p<0.05).

CONCLUSIONS

Lower plasma glutathione level a measure of increased oxidative stress, was an independent predictor of impaired coronary microvascular function and plaque necrotic core.

Myocardial ischemia is not always due to epicardial atheromatous disease

Symptoms related to myocardial ischemia, for the most part, are due to high-grade epicardial coronary artery stenoses. However, in some instances at coronary angiography, no such lesions are seen to account for symptoms due to an imbalance between myocardial oxygen supply and myocardial oxygen demand. Thus, the finding of normal or nonobstructive epicardial coronary arteries at coronary angiography does not exclude the presence of myocardial ischemia in some patients.

Ranolazine improves angina in women with evidence of myocardial ischemia but no obstructive coronary artery disease

OBJECTIVES

We conducted a pilot study for a large definitive clinical trial evaluating the impact of ranolazine in women with angina, evidence of myocardial ischemia, and no obstructive coronary artery disease (CAD).

BACKGROUND

Women with angina, evidence of myocardial ischemia, but no obstructive CAD frequently have microvascular coronary dysfunction. The impact of ranolazine in this patient group is unknown.

METHODS

A pilot randomized, double-blind, placebo-controlled, crossover trial was conducted in 20 women with angina, no obstructive CAD, and ≥ 10% ischemic myocardium on adenosine stress cardiac magnetic resonance (CMR) imaging. Participants were assigned to ranolazine or placebo for 4 weeks separated by a 2-week washout. The Seattle Angina Questionnaire and CMR were evaluated after each treatment. Invasive coronary flow reserve (CFR) was available in patients who underwent clinically indicated coronary reactivity testing. CMR data analysis included the percentage of ischemic myocardium and quantitative myocardial perfusion reserve index (MPRI).

RESULTS

The mean age of subjects was 57 ± 11 years. Compared with placebo, patients on ranolazine had significantly higher (better) Seattle Angina Questionnaire scores, including physical functioning (p = 0.046), angina stability (p = 0.008), and quality of life (p = 0.021). There was a trend toward a higher (better) CMR mid-ventricular MPRI (2.4 [2.0 minimum, 2.8 maximum] vs. 2.1 [1.7 minimum, 2.5 maximum], p = 0.074) on ranolazine. Among women with coronary reactivity testing (n = 13), those with CFR ≤ 3.0 had a significantly improved MPRI on ranolazine versus placebo compared to women with CFR > 3.0 (Δ in MPRI 0.48 vs. -0.82, p = 0.04).

CONCLUSIONS

In women with angina, evidence of ischemia, and no obstructive CAD, this pilot randomized, controlled trial revealed that ranolazine improves angina. Myocardial ischemia may also improve, particularly among women with low CFR. These data document approach feasibility and provide outcome variability estimates for planning a definitive large clinical trial to evaluate the role of ranolazine in women with microvascular coronary dysfunction. (Microvascular Coronary Disease In Women: Impact Of Ranolazine; NCT00570089).