Coronary slow-flow causing transient myocardial hypoperfusion in patients with cardiac syndrome X: Long-term clinical and functional prognosis

Angiographic Coronary Slow Flow Is Not a Valid Surrogate for Invasively Diagnosed Coronary Microvascular Dysfunction

BACKGROUND

Ischemia with no obstructive coronary arteries is frequently caused by coronary microvascular dysfunction (CMD). Consensus diagnostic criteria for CMD include baseline angiographic slow flow by corrected TIMI (Thrombolysis In Myocardial Infarction) frame count (cTFC), but correlations between slow flow and CMD measured by invasive coronary function testing (CFT) are uncertain.

OBJECTIVES

The aim of this study was to investigate relationships between cTFC and invasive CFT for CMD.

METHODS

Adults with ischemia with no obstructive coronary arteries underwent invasive CFT with thermodilution-derived baseline coronary blood flow, coronary flow reserve (CFR), and index of microcirculatory resistance (IMR). CMD was defined as abnormal CFR (<2.5) and/or abnormal IMR (≥25). cTFC was measured from baseline angiography; slow flow was defined as cTFC >25. Correlations between cTFC and baseline coronary flow and between CFR and IMR and associations between slow flow and invasive measures of CMD were evaluated, adjusted for covariates. All patients provided consent.

RESULTS

Among 508 adults, 49% had coronary slow flow. Patients with slow flow were more likely to have abnormal IMR (36% vs 26%; P = 0.019) but less likely to have abnormal CFR (28% vs 42%; P = 0.001), with no difference in CMD (46% vs 51%). cTFC was weakly correlated with baseline coronary blood flow (r = -0.35; 95% CI: -0.42 to -0.27), CFR (r = 0.20; 95% CI: 0.12 to 0.28), and IMR (r = 0.16; 95% CI: 0.07-0.24). In multivariable models, slow flow was associated with lower odds of abnormal CFR (adjusted OR: 0.53; 95% CI: 0.35 to 0.80).

CONCLUSIONS

Coronary slow flow was weakly associated with results of invasive CFT and should not be used as a surrogate for the invasive diagnosis of CMD.

Analysis of Risk Factors and Construction of a Predictive Model for Readmission in Patients with Coronary Slow Flow Phenomenon

Background

Coronary slow flow phenomenon (CSFP) is a phenomenon in which distal vascular perfusion is delayed on angiography, but coronary arteries are not significantly narrowed and there is no other organic cardiac disease. Patients with CSFP may be repeatedly readmitted to the hospital because of chest pain or other symptoms of precordial discomfort, and there is a risk of adverse events. In order to investigate the risk factors affecting the readmission of CSFP patients, a prediction model was constructed with the aim of identifying patients at risk of readmission at an early stage and providing a reference for further clinical intervention.

Methods

In this study, we collected clinical data from 397 CSFP patients between June 2021 and January 2023 in Xinjiang Medical University Hospital. Telephone follow-up clarified whether the patients were readmitted to the hospital. A predictive model for readmission of CSFP patients was constructed using multifactorial logistic regression. Nomogram was used to visualize the model and bootstrap was used to internally validate the model. ROC, DCA and Calibration curve were plotted to evaluate the calibration and discriminative ability of the column line graphs, respectively. Calibration and resolution of the column line graphs, respectively.

Results

A total of 34 of 397 CSFP patients experienced readmission. Smoking history, creatine kinase isoenzyme-MB, total cholesterol, and left ventricular ejection fraction were the predictors of readmission in patients with CSFP. The area under the curve of the Nomogram model was 0.87, which indicated that the model had good predictive ability and differentiation, and the DCA and Calibration curves also indicated that the model had good consistency and was clinically useful.

Conclusion

A readmission prediction model for patients with CSFP may facilitate early identification of patients at potential risk for readmission and timely interventional therapy to improve patient prognosis.

Coronary slow flow and its correlation with reduced left ventricle global longitudinal strain: a case-control study

BACKGROUND

Coronary slow flow (CSF) often links to inflammation and endothelial function disturbance. While conventional ejection fraction measurements fall short in identifying myocardial dysfunction, left ventricular global longitudinal strain (LV GLS) has shown superior efficacy in this regard. Our study aimed to explore subclinical left ventricular systolic dysfunction by assessing LV GLS in patients diagnosed with coronary slow flow (CSF).

METHODS

The study included sixty patients with CSF and sixty control individuals without CSF. Coronary angiography employed the Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) to identify CSF. LV GLS values were evaluated and compared between the two groups.

RESULTS

Significantly reduced LV GLS was evident in the CSF group compared to the control group (- 16.18 ± 1.25 vs. - 19.34 ± 1.33, p < 0.001). A notable correlation (r = 0.492, p < 0.001) between LV GLS and TFC was observed in the CSF group. Multivariate logistic regression analysis highlighted reduced LV-GLS (OR 2.2, 95% CI 1.57-3.09, p < 0.001) and smoking (OR 11.55, 95% CI 3.24-41.2, p < 0.001) as significant predictors for CSF presence. The receiver operating characteristic curve established that an LV GLS value of ≥ - 17.8% accurately predicted the presence of CSF (AUC: 0.958, 95% CI: 0.924-0.991, p < 0.001) with 90% specificity and 91.7% sensitivity.

CONCLUSION

Our study indicates that reduced LV GLS is associated with CSF presence, offering a valuable means to early detect subclinical left ventricular systolic dysfunction in high-risk patients susceptible to heart failure.

TRIAL REGISTRATION

ZU-IRB#7038/12-7-2021 Registered 12 July 2021, email: IRB_123@medicine.zu.edu.eg.

Pharmacological coronary spasm provocative testing in clinical practice: A French Coronary Atheroma and Interventional Cardiology Group (GACI) position paper

Vasospastic angina, also described as Prinzmetal angina, was first described as a variant form of angina at rest with transient ST-segment elevation; it is common and present in many clinical scenarios, including chronic and acute coronary syndromes, sudden cardiac death, arrhythmia and syncope. However, vasospastic angina remains underdiagnosed, and provocative tests are rarely performed. The gold-standard diagnostic approach uses invasive coronary angiography to induce coronary spasm using ergonovine, methylergonovine or acetylcholine as provocative stimuli. The lack of uniform protocol decreases the use and performance of these tests, accounting for vasospastic angina underestimation. This position paper from the French Coronary Atheroma and Interventional Cardiology Group (GACI) aims to review the indications for provocative tests, the testing conditions, drug protocols and positivity criteria.

Long-Term Change in Flow Rates in Patients with Coronary Slow Flow

INTRODUCTION

Coronary slow flow (CSF) is a condition characterized by impaired blood flow rates in the coronary arteries. It can result in severe cardiovascular outcomes. There is no sufficient evidence regarding the certain etiology and reversibility of slow flow patterns and changes in frame counts with long-term management.

METHODS

We retrospectively enrolled 48 patients with chronic coronary syndrome and CSF who underwent a second angiography. A corrected coronary frame rate (CFR) >27 was defined as CSF. We created 3 groups according to the change in CSF status as the improved, not changed, and worsened groups. We compared the CFR and CSF status of the patients between the first and second angiographies within a median of 2.6 years.

RESULTS

We determined a nonsignificant change in cCFR in left anterior descending (LAD) artery (34.4 [18.9] vs. 31.59 [10.3], p = 0.35), circumflex (Cx) artery (42.84 [12.56] vs. 40.66 [13.2], p = 0.35), and right coronary artery (RCA) (57.80 [30.13] vs. 50.32 [19.5], p = 0.11). In the comparison of CSF status of LAD (75% vs. 63%, p = 0.27), Cx (96% vs. 83%, p = 0.09), RCA (94% vs. 94%, p = 1.0) between first and second angiographies, there was no significant change. In the comparison of the 3 groups according to the improvement of CSF status, there was no significant difference in demographic features, change in laboratory parameters, and time between the groups.

CONCLUSION

There was no significant change in the median CFR and CSF status in the overall group between the two angiographies after 3 years.

Evaluation of index of cardio-electrophysiological balance in patients with coronary slow flow

BACKGROUND

Coronary slow flow (CSF) is defined as the late progression of applied contrast through coronary arteries. The cardiac electrophysiological balance index (iCEB) reflects the balance between ventricular depolarisation and repolarisation and provides more information about ventricular arrhythmogenesis (VA) than other electrocardiography (ECG) parameters (QT, corrected QT [QTc], etc.).

AIM

We aimed to evaluate iCEB in patients with CSF.

METHODS

We divided the study population into two groups as CSF and control. The CSF group consisted of 100 patients (33 female, 67 male, mean age 52.2 ± 2.6), while the control group consisted of the same number of age and sex-matched patients (35 female, 65 male, mean age 51.7 ± 1.4). ECG parameters of the study population (QRS duration, QT, T wave peak-to-end (Tp-e) intervals, iCEB (QT/QRS), and iCEBc (heart rate QTc/QRS) rates were calculated and compared between CSF and control groups.

RESULTS

Intervals (QT and QTc intervals) and Tp-e/QTc ratio were greater in the CSF group compared with controls [422.1 ± 12.8 vs. 349.4 ± 14.3 bpm, respectively, p  <  .001; 457.0 ± 12.2 vs. 378.1 ± 12.3 bpm, respectively, p < .001, and 0.19 vs. 0.12, respectively, p  <  .001]. ICEB and iCEBc were significantly greater than controls [(4.9 ± 0.4 vs. 4.2 ± 0.4, respectively, p < .001), (5.7 ± 0.3 vs. 4.4 ± 0.3, respectively, p < .001)].

CONCLUSIONS

ICEB and iCEBc were significantly increased in patients with CSF. This may suggest that CSF may predispose to malign arrhythmias.

The relationship between triglyceride/high-density lipoprotein cholesterol ratio and coronary slow-flow phenomenon

In this study, we aimed to investigate the relationship between high triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C) ratio and coronary slow flow phenomenon (CSFP) in patients undergoing elective coronary angiography for suspected coronary artery disease. This prospective study included a total of 84 CSFP patients and 83 controls with normal coronary flow, as evidenced by coronary angiography. The Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) was used to measure the coronary blood flow velocity. The lipid profiles were analyzed and TG/HDL-C ratio were calculated dividing absolute TG levels by absolute HDL-C levels in peripheral blood. The median TG/HDL-C ratio was higher in the CSFP group than the control group (3.4 [2.6 to 4.9] vs. 2.3 [1.8 to 3], respectively; p < 0.001). The multivariate logistic regression analysis revealed that TG/HDL-C ratio was an independent predictor of CSFP (odds ratio [OR] 1.78, 95% confidence interval [CI] 1.59-2.32; p = 0.001) and TG/HDL-C ratio was positively correlated with the TFC in the CSFP group (r = 0.311, p < 0.001). The area under the receiver operating characteristic curve of TG/HDL-C for the diagnosis of CSFP was 0.73 (95% CI 0.65-0.81; p < 0.001). If a cut-off value of 2.75 was used, higher levels of TG/HDL-C ratio could predict the presence of CSFP with 72% sensitivity and 71% specificity. Our study results suggest that TG/HDL-C ratio is associated with CSFP and may be a useful biomarker for predicting CSFP and its severity.

Slow Flow Phenomenon Impairs the Prognosis of Coronary Artery Ectasia as Well as Coronary Atherosclerosis

Introduction:

Coronary artery ectasia (CAE) is one of the uncommon cardiovascular disorders and its prognosis is still debated.

Objective:

We aimed to review long-term follow-up data in patients with CAE and to evaluate the prognosis of CAE patients with coronary slow flow phenomenon (CSFP).

Methods:

This study had a prospective design and 143 patients with CAE were included. The angiographic and demographic characteristics were reviewed in detail. The patients were categorized, based on concomitant coronary artery stenosis detected by angiography, as CCAE group (n=87, ≥30% luminal stenosis) and ICAE group (n=56, <30% luminal stenosis) and also categorized by the coronary flow as CSFP group (n=51) and normal flow coronary ectasia - NCEA group (n=92). All patients were re-evaluated at 6-month intervals. Follow-up data, cardiovascular (CV) mortality, hospitalization and major adverse cardiac events (MACE) were collected. The level of statistical significance was set at 5%.

Results:

Patients were followed up for an average of 56.9±7.4 months. During the follow-up, statistically significant differences were found in hospitalization, CV mortality and MACE between the CCAE and ICAE groups (P=0.038, P=0.003, P=0.001, respectively). The CSFP and NCEA groups were also compared. There was a statistical difference with respect to hospitalization between the CFSP and NCEA groups (P=0.001), but no difference was observed in terms of MACE and CV mortality (P=0.793 and P=0.279).

Conclusion:

CSFP accompanying CAE may be a predictor of hospitalization. Significant atherosclerotic plaques coexisting with CAE may be predictive for MACE.

The lncRNA MALAT1 participates in regulating coronary slow flow endothelial dysfunction through the miR-181b-5p-MEF2A-ET-1 axis

BACKGROUND

Coronary slow flow (CSF) refers to coronary arteries with no obvious stenosis but have slow coronary flow without effective treatment. The main cause of CSF is endothelial dysfunction. The long non-coding RNA (lncRNA) MALAT1 is involved in regulating endothelial dysfunction, but its role in CSF endothelial dysfunction is still unclear.

METHODS

We included 41 CSF patients and 37 controls in the study, who all underwent coronary angiography, echocardiography, and brachial artery flow-mediated dilatation (FMD) examination. Human umbilical vein endothelial cells (HUVECs) stimulated by oxygen-glucose deprivation were used as CSF-induced HUVECs. Plasma endothelin-1 (ET-1) concentrations were determined by enzyme-linked immunosorbent assay (ELISA). The expression levels of MALAT1, miR-181b-5p, myocyte enhancer factor 2A (MEF2A), and ET-1 were measured by qRT-PCR or western blotting. Cell proliferation was determined by 5-ethynyl-2'-deoxyuridine (EdU) and Cell Counting Kit-8 (CCK-8) assays. Apoptosis was examined by flow cytometry. The relationship between miR-181b-5p and MALAT1 or MEF2A was verified by dual-luciferase reporter assay. MEF2A binding directly to the ET-1 promoter region was verified via chromatin immunoprecipitation (ChIP) assay.

RESULTS

MALAT1 and ET-1 were increased, and miR-181b-5p was decreased in the peripheral blood of the CSF patients, and could be used as predictors of CSF. In the CSF-induced HUVECs, MALAT1 was highly expressed, and MALAT1 knockdown improved endothelial function. In contrast, miR-181b-5p was downregulated in the CSF-induced HUVECs, and miR-181b-5p overexpression improved endothelial function. While MEF2A was highly enriched in CSF-induced HUVECs, MEF2A knockdown reduced ET-1 and increased the endothelial function of CSF-induced HUVECs as a transcriptional regulator of ET-1. MALAT1 modulated MEF2A expression positively by sponging miR-181b-5p.

CONCLUSIONS

Endothelial function is reduced in CSF. MALAT1 participates in regulating CSF endothelial dysfunction through the miR-181b-5p-MEF2A-ET-1 axis, and could provide a new target for CSF treatment.

Assessment of the relationship between coronary flow rates and myocardial perfusion abnormality in patients with nonobstructive coronary artery disease: an observational study in cardiac syndrome X and coronary slow flow

OBJECTIVES

In this study, we evaluated and compared the level of myocardial ischaemia caused by cardiac syndrome X (CSX) and coronary slow flow (CSF) with single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), and determined if changes in the level of myocardial ischaemia exist in CSF and CSX cases according to thrombolysis in myocardial infarction frame count (TFC).

MATERIALS AND METHODS

The study population consisted of 66 patients with CSF and 78 angiographically normal patients (36 of them with CSX and 42 of them healthy controls). The coronary flow rates of all patients were documented using TFC. Subsequently, all patients were evaluated with SPECT-MPI and categorized into the following groups according to their results: patients with CSF, patients with CSX, and patients with normal coronary arteries. Finally, we investigated whether a relationship existed between the SPECT-MPI and TFC results from these three groups.

RESULTS

All ischaemia scores for MPI were significantly higher in the CSF group than in the CSX and control groups (P < 0.05). TFC was significantly associated with the severity of ischaemia in the CSF patients. There was a significant positive correlation between the summon difference score (SDS) and mean TFC value (P < 0.05) as well as between the SDS and each individual coronary TFC value in the CSF patients (P < 0.05). The number of vessels involved in CSF was positively correlated with the SDS.

CONCLUSION

CSF is associated with more severe myocardial ischaemia than CSX. The level of myocardial ischaemia on SPECT-MPI was correlated with the TFC and the number of affected coronary vessels in patients with CSF. These results suggest that CSF is a more serious clinical entity than CSX, and that the clinical severity of CSF appears to increase as the coronary flow rate decreases.

Clinical Profile and Outcome in Patients with Coronary Slow Flow Phenomenon

The coronary slow flow phenomenon (CSFP) is a poorly recognized clinical entity characterized by delayed distal vessel opacification in the absence of epicardial coronary stenosis and presently lack of specific data on the clinical profile and outcome. We investigated a cohort of 429 patients who fulfilled the criteria for CSFP to explore the clinical feature, outcome, and risk factor of prognosis. Two teams (clinical center and core lab) were blind to patient data for the assessment of coronary angiograph using corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC). The study cohort consisted of 429 patients (294 men, 68.5%), aged from 30 to 78 years (mean, 54 years). Two hundred patients (46.6%) out of 429 patients had a history of hypertension, 72 (16.8%) had diabetes mellitus, and 222 (51.7%) had dyslipidemia. All the rates of agreement between two teams in evaluating whether normal flow (CTFC ≤ 27 frames) or slow flow (CTFC > 27 frames) were moderate (0.40 < κ < 0.75) for the three arteries. Follow-up (mean, 3.8 years) was done for 421 patients (98.1%). The major adverse cardiovascular events (MACE) occurred in 39 patients (9.3%) out of 421 patients. Multivariate analysis showed that the risk of MACE approximately doubles with age >50 years (hazard ratio (HR) = 2.2, 95% CI: 1.0 to 4.9, and P=0.042), hypertension (HR = 2.1, 95% CI: 1.1 to 4.2, and P=0.021), and dyslipidemia (HR = 2.0, 95% CI: 1.0 to 3.9, and P=0.042). CSFP affects predominantly patients at middle age and above but can occur in any age group; CSFP should be more concerned, particularly in patients >50 years old with hypertension and dyslipidemia.

'Primary' Microvascular Angina: Clinical Characteristics, Pathogenesis and Management

Microvascular angina (MVA), i.e. angina caused by abnormalities of the coronary microcirculation, is increasingly recognised in clinical practice. The pathogenetic mechanisms of MVA are heterogeneous and may involve both structural and functional alterations of coronary microcirculation, and functional abnormalities may variably involve an impairment of coronary microvascular dilatation and an increased microvascular constrictor activity. Both invasive and non-invasive diagnostic tools exist to identify patients with MVA in clinical practice. Prognosis has been reported to be good in primary MVA patients, although the prognostic implications of coronary microvascular dysfunction (CMVD) in more heterogeneous populations of angina patients need further assessment. Management of primary MVA can be challenging, but pharmacological and non-pharmacological treatments exist that allow satisfactory control of symptoms in most patients.

The role of urotensin II and atherosclerotic risk factors in patients with slow coronary flow

BACKGROUND

Slow coronary flow (SCF) is an angiographic finding characterized with delayed opacification of epicardial coronary arteries without obstructive coronary disease. Urotensin II (UII) is an important vascular peptide, which has an important role in hypertension, coronary artery disease, and vascular remodeling in addition to potent vasoconstrictor effect.

OBJECTIVES

We investigated UII levels, hypertension, and other atherosclerotic risk factors in patients with SCF, a variety of coronary artery disease.

METHODS

We enrolled 14 patients with SCF and 29 subjects with normal coronary arteries without SCF. We compared the UII levels and the atherosclerotic risk factors between patients with SCF and control subjects with normal coronary flow.

RESULTS

UII concentrations were significantly higher in patients with SCF compared to controls (711.0 ± 19.4 vs. 701.5 ± 27.2 ng/mL, p = 0.006). We detected a positive correlation between SCF and age (r = 0.476, p = 0.001), BMI (r = 0.404, p = .002), UII concentrations (r = 0.422, p = 0.006), and hypertension (r = 0.594, p = 0.001).

CONCLUSION

We identified increased UII levels in patients with SCF. We think that UII concentrations may be informative on SCF pathogenesis due to relationship with inflammation, atherosclerosis, and vascular remodeling.

Increased circulating soluble urokinase-type plasminogen activator receptor (suPAR) levels in patients with slow coronary flow

Introduction

Slow coronary flow (SCF) is an angiographic phenomenon characterized by delayed opacification of epicardial coronary arteries without an obstructive coronary disease. Serum soluble urokinase-type plasminogen activator receptor (suPAR) levels seem closely related to atherosclerosis due to increased inflammation and prothrombotic state. We studied whether circulating suPAR is related to SCF.

Material and methods

The present study was cross-sectional and observational. It included 75 individuals who underwent coronary angiography with suspected CAD and had angiographically normal coronary arteries of varying coronary flow rates. The relationship between suPAR, C-reactive protein (CRP) and SCF was investigated. Forty patients with isolated SCF (mean age: 46.0 ±4.14 years) and 35 age- and gender-matched control participants with normal coronary flow (NCF) and normal coronary arteries (NCA) (mean age: 46.0 ±5.7 years) were included in the study. We used logistic regression analysis to determine the predictors of SCF.

Results

The clinical characteristics were not statistically significantly different between SCF and NCA groups. Serum suPAR level was significantly higher in the SCF group than the control group (2.5–5.4 ng/ml vs. 0.1–1.4 ng/ml; p < 0.001). Also the serum CRP level was higher in the CSF group than the control group (1.57 ±0.43 mg/l vs. 0.53 ±0.23 mg/l; p < 0.001).

Conclusions

This study revealed significantly increased serum suPAR levels in patients with SCF. Although we cannot draw conclusions on the underlying pathological process of SCF, we believe that these findings may be pioneering for further studies investigating the specific roles of circulating suPAR in the SCF phenomenon in the coronary vasculature.

Diagnosis of coronary microvascular dysfunction - Present status

Definite clinical diagnosis of microvascular angina is not possible with the existing knowledge. Resting electrocardiogram may be normal, and exercise electrocardiogram may be unremarkable. Echocardiography usually does not show regional wall motion abnormalities. Transthoracic Doppler echocardiography can satisfactorily evaluate only left anterior descending coronary artery and that too in some patients. Radio-isotope imaging can detect only severe localized disease. Noninvasive diagnosis needs high index of suspicion. At present, definite diagnosis is based on documentation of normal epicardial coronaries, coronary flow reserve less than 2.5 on adenosine induced hyperemia, and absence of spasm of epicardial coronaries on acetylcholine provocation. Invasive evaluation is costly, needs sophisticated equipments and expertise. Therapeutic and prognostic implications of various parameters remains to be evaluated. At present invasive evaluation is recommended only for patients with intractable symptoms with unconfirmed diagnosis, requiring repeated hospitalization and evaluation with failure of empirical therapy.

A case of coronary microvascular spasm with slow flow induced by the intracoronary acetylcholine provocation test

Microvascular angina is a rare condition in which myocardial ischemia is caused by microvascular dysfunction without any abnormalities of the epicardial coronary arteries. In clinical practice, it is difficult to diagnose because the microvascular alterations cannot be detected by conventional angiography. Herein we present a rare case of a 67-year-old woman with unstable angina pectoris in whom considerably slow coronary flow was induced by the acetylcholine provocation test with mild epicardial arterial spasm, suggesting the presence of microvascular spasm. Moreover, we show that β-methyl-p-[(123)I]-iodophenyl-pentadecanoic ((123)I-BMIPP) single-photon emission computed tomography imaging is useful for proving myocardial ischemia.

Presentation, management, and outcomes of ischaemic heart disease in women

Scientific interest in ischaemic heart disease (IHD) in women has grown considerably over the past 2 decades. A substantial amount of the literature on this subject is centred on sex differences in clinical aspects of IHD. Many reports have documented sex-related differences in presentation, risk profiles, and outcomes among patients with IHD, particularly acute myocardial infarction. Such differences have often been attributed to inequalities between men and women in the referral and treatment of IHD, but data are insufficient to support this assessment. The determinants of sex differences in presentation are unclear, and few clues are available as to why young, premenopausal women paradoxically have a greater incidence of adverse outcomes after acute myocardial infarction than men, despite having less-severe coronary artery disease. Although differential treatment on the basis of patient sex continues to be described, the extent to which such inequalities persist and whether they reflect true disparity is unclear. Additionally, much uncertainty surrounds possible sex-related differences in response to cardiovascular therapies, partly because of a persistent lack of female-specific data from cardiovascular clinical trials. In this Review, we assess the evidence for sex-related differences in the clinical presentation, treatment, and outcome of IHD, and identify gaps in the literature that need to be addressed in future research efforts.

Long-term prognosis of patients with cardiac syndrome X: a review

Aims

Follow-up studies of patients with cardiac syndrome X (CSX) generally report good prognosis. However, some recent studies report an adverse outcome for women.

Methods and results

Structured literature search and meta-analysis for studies regarding prognosis of cardiac syndrome X patients. We identified 85 studies, ultimately selecting 16 for inclusion. Meta-analysis yielded a pooled major cardiac event percentage of 1.5% per 5 years and a pooled vascular event percentage of 4.8% per 5 years (n = 16 studies, n = 1694 patients). Fourteen studies reported upon the recurrence rate of angina pectoris: the pooled percentage of angina recurrence was 55% (n = 1336 patients).

Conclusion

The present review of recent archival literature demonstrates an overall major cardiac event rate of 1.5% per 5 years. Although this is an excellent prognosis for CSX patients, the quality of life is impaired because of the high recurrence rate of angina pectoris (55%).

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.

Usefulness of impairment of cardiac adrenergic nerve function to predict outcome in patients with cardiac syndrome X

Patients with cardiac syndrome X (CSX) have an excellent long-term prognosis, but a significant number show worsening angina over time. Previous studies have found a significant impairment of cardiac uptake of iodine-123-meta-iodobenzylguanidine (MIBG) on myocardial scintigraphy, indicating abnormal function of cardiac adrenergic nerve fibers. The aim of this study was to assess whether cardiac MIBG results can predict symptomatic outcome in patients with CSX. Cardiac MIBG scintigraphy was performed in 40 patients with CSX (mean age 58 ± 5 years, 14 men). Cardiac MIBG uptake was measured by the heart/mediastinum uptake ratio and a single photon-emission computed tomographic regional uptake score (higher values reflected lower uptake). Clinical findings, exercise stress test parameters, sestamibi stress myocardial scintigraphy, and C-reactive protein serum levels were also assessed. At an average follow-up of 79 months (range 36 to 144), no patient had died or developed acute myocardial infarction. Cardiac MIBG defect score was significantly lower in patients with worsening versus those without worsening of angina status (13 ± 7 vs 38 ± 28, p = 0.001), in those with versus those without hospital readmission because of recurrent chest pain (15 ± 9 vs 35 ± 29, p = 0.01), and in those who underwent versus those who did not undergo repeat coronary angiography (11 ± 7 vs 36 ± 27, p = 0.001). Significant correlations were found between quality of life (as assessed by the EuroQoL scale) and heart/mediastinum ratio (r = 0.48, p = 0.002) and cardiac MIBG uptake score (r = -0.69, p <0.001). No other clinical or laboratory variable showed a significant association with clinical end points. In conclusion, in patients with CSX, abnormal function of cardiac adrenergic nerve fibers, as assessed by an impairment of cardiac MIBG uptake, identifies those with worse symptomatic clinical outcomes.

Documentation of impaired coronary blood flow in chronic obstructive pulmonary disease patients

BACKGROUND

In the current study, the effects of moderate to severe chronic obstructive pulmonary disease (COPD) on coronary blood flow in patients with angiographically proven normal coronary arteries was evaluated.

METHODS AND RESULTS

A total of 85 patients with moderate to severe COPD and 39 age- and sex-matched control partcipants, who underwent diagnostic coronary angiography and found to have normal epicardial coronary angiogram constituted the COPD and control groups, respectively. The 2 groups were compared for Thrombolysis In Myocardial Infarction (TIMI) frame counts in each major coronary artery. The TIMI frame count of the COPD group was significantly higher than that of control group for all 3 major individual coronary arteries: left anterior descending (corrected), 37+/-13 vs 20+/-4; right coronary artery, 32+/-14 vs 21+/-4; and left circumflex artery, 34+/-12 vs 20+/-5, (P<0.001 for all). In addition, TIMI frame counts in individual coronary arteries were found to be positively correlated with forced expiratory volume 1 s percent, serum high sensitive C-reactive protein and fibrinogen concentrations, in the COPD group.

CONCLUSIONS

Our findings suggest that an increased slow coronary flow might be a manifestation of harmful effects of COPD on the coronary circulation, regardless of the underlying mechanism.