Coronary Slow Flow Phenomenon Clinical Findings and Predictors

The phenomenon of drug-coating embolism during lower extremity endovascular interventions with paclitaxel-coated balloon

INTRODUCTION

There is a risk of distal embolization lower extremity endovascular interventions. Possibly a drug-coating embolism caused by coating detachment from intravascular devices.

METHODS

This review focuses on providing updated information on distal embolism in endovascular revascularization of lower extremity arteries, including the use of drug-coated balloons.

RESULTS

Drug-coating embolism is a special case of distal embolization during recanalization of the arteries of the lower extremities. Preclinical studies have demonstrated embolization of drug-coated balloons during angioplasty of lower extremity arteries. However, the clinical role of drug-coating embolism is not completely clear. A 2020 meta-analysis found an increased risk of major lower extremity amputation after drug-coated balloon angioplasty in patients with critical limb ischemia. But long-term research is emerging to support the safety of using these devices. Perhaps a more thorough assessment of the quality of life and the degree of compensation of lower limb ischemia with an intraoperative assessment of the frequency of peripheral embolizations using ultrasound emboli detection, as well as microcirculation with transcutaneous oximetry and laser Doppler flowmetry of the operated lower limb will allow a more detailed study of the phenomenon of drug-coating embolism and its impact on long-term clinical outcomes.

CONCLUSION

According to the results of preclinical studies, the use of paclitaxel-coated balloons leads to an increase in the concentration of paclitaxel in distal skeletal muscles. However, paclitaxel concentration in skeletal muscle was significantly higher in first-generation DCBs. The non-target effects of drug-coating balloon are not fully understood and require further study. Understanding the phenomenon of drug-coating embolism can help physicians to better assess the patient risk and to minimize complications.

Could Pan-Immune-Inflammation Value be a Marker for the Diagnosis of Coronary Slow Flow Phenomenon?

Inflammation plays a key role in the pathogenesis of the coronary slow flow phenomenon (CSFP). The newly developed inflammatory marker, pan-immune-inflammation value (PIV), is associated with adverse cardiovascular events. This study investigated the predictive value of PIV for diagnosing CSFP in comparison to other inflammation-based markers. A total of 214 patients, 109 in the CSFP group and 105 in the normal coronary flow (NCF) group, were retrospectively included in the study. Coronary flow was calculated using the Thrombolysis in Myocardial Infarction frame count method. In addition to PIV, other inflammatory markers such as neutrophil-lymphocyte ratio, platelet-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) were calculated for the patients. The average age of patients was 50.3 ± 8.4, with a male ratio of 55.1%. Compared to the NCF group, patients in the CSFP group had higher levels of hyperlipidemia, glucose, triglyceride, NLR, PLR, SII, and PIV, while their high-density lipoprotein cholesterol (HDL-C), was lower (p < 0.05). Logistic regression analysis demonstrated that HDL-C, glucose, triglyceride, and PIV were independent predictor factors for CSFP (p < 0.05). PIV is a strong and independent predictor factor for CSFP and superior in predicting CSFP compared to other inflammatory markers.

Differential gene expression and miRNA regulatory network in coronary slow flow

Coronary slow flow (CSF) is characterized by slow progression of coronary angiography without epicardial stenosis. The aim of this study was to explore the potential biomarkers and regulatory mechanism for CSF. Peripheral blood mononuclear cells from 3 cases of CSF and 3 healthy controls were collected for high-throughput sequencing of mRNA and miRNA, respectively. The differentially expressed mRNAs (DE-mRNAs) and miRNAs (DE-miRNAs) was identified. A total of 117 DE-mRNAs and 32 DE-miRNAs were obtained and they were mainly enriched in immune and inflammatory responses. Twenty-six DE-mRNAs were the predicted target genes for miRNAs by RAID, and then the regulatory network of 15 miRNAs were constructed. In addition, through the PPI network, we identified the three genes (FPR1, FPR2 and CXCR4) with larger degrees as hub genes. Among them, FPR1 was regulated by hsa-miR-342-3p, hsa-let-7c-5p and hsa-miR-197-3p and participated in the immune response. Finally, we validated the differential expression of hub genes and key miRNAs between 20 CSF and 20 control. Moreover, we found that miR-342-3p has a targeted regulatory relationship with FPR1, and their expression is negatively correlated. Then we established a hypoxia/reoxygenation (H/R) HUVEC model and detected FPR1, cell proliferation and apoptosis. Transfection with miR-342-3p mimics can significantly promote the proliferation of HUVEC under H/R conditions. FPR1 were associated with CSF as a biomarker and may be regulated by miR-342-3p potential biomarkers.

Predictors of non-obstructive coronary slow flow in poorly controlled type 2 diabetes mellitus: a cross-sectional study

BACKGROUND

Coronary slow flow (CSF) can occur due to various factors, such as inflammation, small vessel disease, endothelial dysfunction, and inadequate glucose control. However, the exact pathological mechanisms behind CSF remain incompletely understood. The objective of this study was to identify the risk factors associated with slow coronary flow in individuals with Type 2 Diabetes Mellitus (T2DM) who have non-obstructive coronary artery disease (CAD) and experience CSF.

METHODS

We conducted a prospective cohort study involving 120 patients with T2DM who were referred for invasive coronary angiography due to typical chest pain or inconclusive results from non-invasive tests for myocardial ischemia. Using a 2 × 2 design, we categorized patients into groups based on their glycemic control (adequate or poor) and the presence of CSF (yes or no), defined by a TIMI frame count > 27. All patients had non-obstructive CAD, characterized by diameter stenosis of less than 40%. We identified many variables associated with CSF.

RESULTS

Our investigation revealed no significant differences in age, sex, family history of coronary artery disease, ECG ischemia abnormalities, or echocardiographic (ECHO) data between the groups. In patients with adequate glycemic control, hypertension increased the risk of CSF by 5.33 times, smoking by 3.2 times, while dyslipidemia decreased the risk by 0.142. Additionally, hematocrit increased the risk by 2.3, and the platelet-to-lymphocyte ratio (PLR) increased the risk by 1.053. Among patients with poor glycemic control, hematocrit increased the risk by 2.63, and the Neutrophil-to-Lymphocyte Ratio (NLR) by 24.6. Notably, NLR was positively correlated with glycemic control parameters in T2DM patients with CSF.

CONCLUSIONS

In T2DM patients with CSF, various factors strongly correlate with glycemic control parameters and can be employed to predict the likelihood of CSF. These factors encompass hypertension, smoking, increased body mass index (BMI), elevated platelet count, hematocrit, NLR, PLR, and C-reactive protein (CRP).

TRIAL REGISTRATION

Registry: ZU-IRB (ZU-IRB#9419-3-4-2022), Registered on: 3 April 2022, Email: IRB_123@medicine.zu.edu.eg.

Major Adverse Cardiovascular Events and Prognosis in Patients With Coronary Slow Flow

This study aimed to investigate its clinical implications, risk factors, prognosis, and overall long-term outcomes. Demographic profiles, various clinical characteristics, and clinical outcomes were compared between 614 patients with coronary slow flow (CSF) and 428 patients with normal coronary artery. The incidence of CSF was found to be 2.65%. Significant differences were observed between patients with CSF and control subjects in terms of sex, chest tightness, hyperlipidemia, smoking history, alcohol consumption, age, height, weight, body mass index, diastolic blood pressure, heart rate, and body surface area (P < 0.05). CSF (hazard ratio: 1.531; 95% confidence interval: 1.064-2.202; p = 0.022) proved to be independent prognostic predictors of major adverse cardiovascular events (MACEs). Kaplan-Meier survival evaluations for MACEs presented a worser outcome for patients with CSF. Patients with CSF are at high risk for cardiovascular events and experience generally poor clinical outcomes.

Changes of left atrial morphology and function evaluated with four-dimensional automated left atrial quantification echocardiography in patients with coronary slow flow phenomenon and preserved left ventricular ejection fraction

BACKGROUND

Coronary slow flow phenomenon (CSFP) can cause left ventricular diastolic dysfunction (LVDD). In multiple studies, the left atrial (LA) strain has been reported to be an excellent parameter for assessing LVDD. The 4-dimensional automated LA quantification (4D Auto LAQ) dedicated to the LA was recently available. Our study aimed to evaluate subclinical changes in LA morphology and function with 4D Auto LAQ in patients with CSFP and preserved left ventricular ejection fraction (LVEF).

METHODS

Forty-eight patients with CSFP confirmed with coronary angiography and 46 age and gender-matched controls with normal coronary flow were enrolled. The thrombolysis in myocardial infarction frame count (TFC) method was used to record coronary blood flow velocities for each major coronary artery. LA volume, LA longitudinal and circumferential strains during each of the three LA phases (reservoir, conduit, and contraction), LA total emptying fraction (LATEF), LA active emptying fraction (LAAEF), and LA passive emptying fraction (LAPEF) were quantified with 4D Auto LAQ analysis.

RESULTS

Compared with controls, LA longitudinal reservoir strain (LASr), LA longitudinal strain during the conduit phase (LAScd), LA contraction strain (LASct), LA conduit circumferential strain (LAScd-c), LATEF, LAPEF decreased significantly in individuals with CSFP. Of the 4D- LAQ parameters, only LASr [odds ratio (OR): 0.773, P < 0.001] and LATEF [OR: 0.762, P < 0.001] were associated with CSFP in multivariate analysis. A LASr ≤23.00% can differentiate CSFP from controls [sensitivity, 66.7%; specificity, 93.5%; area under the curve (AUC), 0.823; P < 0.001]. A LASr of ≤19.00% could predict the elevation of LV filling pressure in the CSFP cohort [sensitivity, 76.9%; specificity, 74.3%; area under the curve (AUC), 0.792; P < 0.001]. LASr was the only index to demonstrate significant changes compared to controls in single-vessel CSFP. Compared to the right coronary artery (RCA) and left circumflex (LCX), TFC of the left anterior descending (LAD) artery was the only independent variable of LASr (Standardized Coefficients: -0.386, P = 0.037).

CONCLUSIONS

Impairment of LA reservoir function reflected by changes in LASr and LATEF can be seen in patients with CSFP. LASr could predict the elevation of LV filling pressure in CSFP individuals. LASr is more sensitive than LATEF in detecting LA reservoir dysfunction in single-vessel CSFP. CSFP in LAD exerts a more prominent influence on LASr than RCA or LCX.

The expression levels of PPAR-α/γ and UCP1/2 on the slow coronary flow phenomenon; results from a case-control study

PURPOSE

The slow coronary flow (SCF) phenomenon is considered a coronary artery disorder. Because of the critical function of peroxisome proliferator-activated receptors (PPARs) in regulating the oxidative stress and inflammatory reactions in cardiovascular disease, The aim of the current study was to investigate the expression of the genes for uncoupling proteins 1 and 2 (UCP1 and UCP2), peroxisome proliferator-activated receptors and (PPAR- PPAR-), and PPAR- in SCF patients.

METHODS

In this case-control study, coronary angiography examination was used to analyze 35 individuals with SCF and 35 subjects with normal coronary flow (NCF). SCF was diagnosed using the TIMI (thrombolysis in myocardial infarction frame count) method. The SCF phenomenon is thought to be the TIMI > 27. In the peripheral blood mononuclear cells (PBMCs), the messenger ribonucleic acid (mRNA) expression levels of the PPAR-, PPAR-, UCP1, and UCP2 genes were evaluated.

RESULTS

UCP1 and UCP2 expression levels were significantly higher in the SCF group compared to the NCF group (P = 0.034 and P0.001, respectively). The PPAR- and PPAR- levels were found to be significantly lower in the SCF group compared to the NCF group (P = 0.015, P0.001, respectively). According to the results of the logistic regression analysis, high UCP1 and UCP2 levels and low PPAR- and PPAR- levels are each independent predictors of the SCF phenomenon.

CONCLUSION

This research provided evidence about the potential role of PPAR-α, PPAR-γ, UCP1, and UCP2 as biomarkers in SCF. More investigations are suggested to assess the functions of these factors in SCF patients mechanistically.

Thromboembolic risk scores in patients with non-obstructive coronary architecture with and without coronary slow flow: A case-control study

AIM

Coronary slow flow phenomenon (CSFP) detected on coronary angiography (CA) has been related to poor prognosis. We sought to examine the relationship between thromboembolic risk scores, routinely used in cardiology practice, and CSFP.

METHODS

This single-center, retrospective, case-control study comprised 505 individuals suffering from angina and had verified ischemia between January 2021 and January 2022. Demographic and laboratory parameters were obtained from the hospital database. The following risk scores were calculated; CHA₂DS₂-VASc, M-CHA₂DS₂-VASc, CHA₂DS₂-VASc-HS, R₂-CHA₂DS₂-VASc, M-R₂-CHA₂DS₂-VASc, ATRIA, M-ATRIA, M-ATRIA-HSV. The overall population was divided into two groups; coronary slow flow and coronary normal flow. Multivariable logistic regression was performed to compare risk scores between patients with and without CSFP. Pairwise comparisons were then undertaken to test performance in determining CSFP.

RESULTS

The mean age was 51.7 ± 10.7 years, of whom 63.2% were male. CSFP was detected in 222 patients. Those with CSFP had higher rates of male gender, diabetes, smoking, hyperlipidemia, and vascular disease. All scores were higher in CSFP patients. Multivariable logistic regression analysis found that CHA₂DS₂-VASc-HS score was the most powerful determinant of CSFP among all risk schemes (for each one-point increase in score OR = 1.90, p < 0.001; for score of 2-3 OR = 5.20, p < 0.001; for score of >4 OR = 13.89, p < 0.001). Also, the CHA₂DS₂-VASc-HS score provided the best discriminative performance, with a cut-off value of ≥2 in identifying CSFP (AUC = 0.759, p < 0.001).

CONCLUSION

We showed that thromboembolic risk scores may be associated with CSFP in patients with non-obstructive coronary architecture who underwent CA. The CHA₂DS₂-VASc-HS score had the best discriminative ability.

Relationship between increased systemic immune-inflammation index and coronary slow flow phenomenon

Background

Systemic immune-inflammation index (SII, platelet × neutrophil/lymphocyte ratio), a new marker of inflammation, is associated with adverse cardiovascular events, but its relationship with coronary slow flow phenomenon (CSFP) is unclear. Therefore, we aimed to investigate the relationship between SII and CSFP.

Methods

We enrolled consecutive patients who presented with chest pain, with normal/near-normal coronary angiography findings (n = 89 as CSFP group; n = 167 as control group). The baseline characteristics, laboratory parameters and angiographic characteristics of the two groups were compared.

Results

SII levels were significantly higher in the CSFP group than in the control group (409.7 ± 17.7 vs. 396.7 ± 12.7, p < 0.001). A significant positive correlation between SII and the mean thrombolysis in myocardial infarction frame count (mTFC) was found (r = 0.624, p < 0.001). SII increased with the number of coronary arteries involved in CSFP. In multivariate logistic regression analysis, SII/10 was an independent predictor of CSFP (odds ratio: 1.739, p < 0.001). In addition, the SII level > 404.29 was a predictor of CSFP with 67.4% sensitivity and 71.9% specificity.

Conclusions

SII can predict the occurrence of CSFP.

Coronary microvascular disease: The "Meeting Point" of Cardiology, Rheumatology and Endocrinology

BACKGROUND

Exertional chest pain/dyspnea or chest pain at rest are the main symptoms of coronary artery disease (CAD), which are traditionally attributed to insufficiency of the epicardial coronary arteries. However, 2/3 of women and 1/3 of men with angina and 10% of patients with acute myocardial infarction have no evidence of epicardial coronary artery stenosis in X-ray coronary angiography. In these cases, coronary microvascular disease (CMD) is the main causative factor.

AIMS

To present the pathophysiology of CMD in Cardiology, Rheumatology and Endocrinology.

MATERIALS-METHODS

The pathophysiology of CMD in Cardiology, Rheumatology and Endocrinology was evaluated. It includes impaired microvascular vasodilatation, which leads to inability of the organism to deal with myocardial oxygen needs and, hence, development of ischemic pain. CMD, observed in inflammatory autoimmune rheumatic and endocrine/metabolic disorders, brings together Cardiology, Rheumatology and Endocrinology. Causative factors include persistent systemic inflammation and endocrine/metabolic abnormalities influencing directly the coronary microvasculature. In the past, the evaluation of microcirculation was feasible only with the use of invasive techniques, such as coronary flow reserve assessment. Currently, the application of advanced imaging modalities, such as cardiovascular magnetic resonance (CMR), can evaluate CMD non-invasively and without ionizing radiation.

RESULTS

CMD may present with a variety of symptoms with 1/3 to 2/3 of them expressed as typical chest pain in effort, more commonly found in women during menopause than in men. Atypical presentation includes chest pain at rest or exertional dyspnea,but post exercise symptoms are not uncommon. The treatment with nitrates is less effective in CMD, because their vasodilator action in coronary micro-circulation is less pronounced than in the epicardial coronary arteries.

DISCUSSION

Although both classic and new medications have been used in the treatment of CMD, there are still many questions regarding both the pathophysiology and the treatment of this disorder. The potential effects of anti-rheumatic and endocrine medications on the evolution of CMD need further evaluation.

CONCLUSION

CMD is a multifactorial disease leading to myocardial ischemia/fibrosis alone or in combination with epicardial coronary artery disease. Endothelial dysfunction/vasospasm, systemic inflammation, and/or neuroendocrine activation may act as causative factors and bring Cardiology, Rheumatology and Endocrinology together. Currently, the application of advanced imaging modalities, and specifically CMR, allows reliable assessment of the extent and severity of CMD. These measurements should not be limited to "pure cardiac patients", as it is known that CMD affects the majority of patients with autoimmune rheumatic and endocrine/metabolic disorders.

Slow Coronary Blood Flow: Pathogenesis and Clinical Implications

Coronary slow flow (CSF) phenomenon, also known as cardiac syndrome Y, is defined as the delayed opacification of the coronary vasculature at the distal level. Different hypotheses and theories have been postulated about its substrate and mechanism, such as microvascular and endothelial dysfunction. Several studies have confirmed that CSF is a cause of ischaemia detected by non-invasive testing. Clinically, it can present as angina pectoris, acute coronary syndrome and sudden cardiac death. It has an incidence of 1–5% in patients undergoing coronary angiography and has been most frequently found in young men who are smokers with metabolic syndrome. There are no established treatments for CSF and further studies are still necessary.

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.

Echocardiographic and laboratory findings in coronary slow flow phenomenon: cross-sectional study and review

Background

Coronary sow-flow phenomenon (CSFP) is defined as slow passage of the contrast injected into the coronary arteries without distal obstruction of the vessel.

Methods

The present study was a cross-sectional, descriptive-analytical study performed at the Seyed-al-Shohada Heart Center during 2018–2019. The eligible patients based on the inclusion and exclusion criteria were divided into the study group showing the CSFP and the control group with normal epicardial coronary arteries.

Results

The study included 124 patients. 67.9% of the study group and 39.4% of the control group were male patients (p-value = 0.001), and the mean patient age was 52.18 ± 12.55 and 51.77 ± 10.36 years in the study and control groups, respectively (p-value = 0.18). The study group had a significantly higher BMI than the control group (p < 0.05) and also a higher prevalence of smoking and hypertension. The variables of ALC, Hct, Plt, MPV, RDW, Cr, triglyceride, TC, and LDL, were higher in the study group. Given the echocardiographic findings, the mean E wave was significantly lower in the study group, while the control group had a significantly higher GLS (p-value = 0.01). Also, left anterior descending artery was the most common artery involved with CSFP.

Conclusion

The CSFP was significantly more common in men, smokers, hypertensive patients, and patients with high BMI. Moreover, these patients had significantly higher platelet count, MPV, LDL, and FBS. Some other laboratory variables were also higher in these patients. Given the echocardiographic findings, mild diastolic dysfunction and low GLS were also observed in the study group.

Prevalence and predictors of slow coronary flow phenomenon in Kermanshah province

Introduction: This study was conducted to investigate prevalence and predictors of slow coronary flow phenomenon (SCF) phenomenon. Methods: This cross-sectional study was performed at Imam Ali Cardiovascular Hospital affiliated with the Kermanshah University of Medical Sciences (KUMS), Kermanshah province, Iran. From March 2017 to March 2019, all the patients who underwent coronary angiography were enrolled in this study. Data were obtained using a checklist developed based on the study's aims. Independent samples t tests and chi- square test (or Fisher exact test) were used to assess the differences between subgroups. Multiple logistic regression model was applied to evaluate independent predictors of SCF phenomenon. Results: In this study, 172 (1.43%) patients with SCF phenomenon were identified. Patients with SCF were more likely to be obese (27.58±3.28 vs. 24.12±3.26, P <0.001), hyperlipidemic (44.2 vs. 31.7, P <0.001), hypertensive (53.5 vs. 39.1, P <0.001), and smoker (37.2 vs. 27.2, P =0.006). Mean ejection fraction (EF) (51.91±6.33 vs. 55.15±9.64, P <0.001) was significantly lower in the patients with SCF compared to the healthy controls with normal epicardial coronary arteries. Mean level of serum triglycerides (162.26±45.94 vs. 145.29±35.62, P <0.001) was significantly higher in the patients with SCF. Left anterior descending artery was the most common involved coronary artery (n = 159, 92.4%), followed by left circumflex artery (n = 50, 29.1%) and right coronary artery (n = 47, 27.4%). Body mass index (BMI) (OR 1.78, 95% CI 1.04-2.15, P <0.001) and hypertension (OR 1.59, CI 1.30-5.67, P =0.003) were independent predictors of SCF phenomenon. Conclusion: The prevalence of SCF in our study was not different from the most other previous reports. BMI and hypertension independently predicted the presence of SCF phenomenon.

Coronary Microvascular Dysfunction

Many patients with chest pain undergoing coronary angiography do not show significant obstructive coronary lesions. A substantial proportion of these patients have abnormalities in the function and structure of coronary microcirculation due to endothelial and smooth muscle cell dysfunction. The coronary microcirculation has a fundamental role in the regulation of coronary blood flow in response to cardiac oxygen requirements. Impairment of this mechanism, defined as coronary microvascular dysfunction (CMD), carries an increased risk of adverse cardiovascular clinical outcomes. Coronary endothelial dysfunction accounts for approximately two-thirds of clinical conditions presenting with symptoms and signs of myocardial ischemia without obstructive coronary disease, termed "ischemia with non-obstructive coronary artery disease" (INOCA) and for a small proportion of "myocardial infarction with non-obstructive coronary artery disease" (MINOCA). More frequently, the clinical presentation of INOCA is microvascular angina due to CMD, while some patients present vasospastic angina due to epicardial spasm, and mixed epicardial and microvascular forms. CMD may be associated with focal and diffuse epicardial coronary atherosclerosis, which may reinforce each other. Both INOCA and MINOCA are more common in females. Clinical classification of CMD includes the association with conditions in which atherosclerosis has limited relevance, with non-obstructive atherosclerosis, and with obstructive atherosclerosis. Several studies already exist which support the evidence that CMD is part of systemic microvascular disease involving multiple organs, such as brain and kidney. Moreover, CMD is strongly associated with the development of heart failure with preserved ejection fraction (HFpEF), diabetes, hypertensive heart disease, and also chronic inflammatory and autoimmune diseases. Since coronary microcirculation is not visible on invasive angiography or computed tomographic coronary angiography (CTCA), the diagnosis of CMD is usually based on functional assessment of microcirculation, which can be performed by both invasive and non-invasive methods, including the assessment of delayed flow of contrast during angiography, measurement of coronary flow reserve (CFR) and index of microvascular resistance (IMR), evaluation of angina induced by intracoronary acetylcholine infusion, and assessment of myocardial perfusion by positron emission tomography (PET) and magnetic resonance (CMR).

Increased plasma lipoprotein-associated phospholipase A2 levels are associated with coronary slow flow

OBJECTIVE

Coronary slow flow (CSF) is characterized by delayed opacification of distal epicardial coronary arteries without significant coronary stenosis. In addition, The changes of lipoprotein-associated phospholipase A2 (Lp-PLA₂) as a significant predictive factor for CSF remain controversial. The study aims to investigate the association between plasma Lp-PLA₂ and CSF.

METHODS

In this retrospective study, 170 consecutive patients who underwent coronary angiography were enrolled in Beijing Anzhen Hospital from January 2017 to September 2019, and were divided into CSF group and normal control groups. According to coronary blood flow rate measured by the thrombolysis in myocardial infarction frame count (TFC) method, CSF was defined as TFC > 27. Serum Lp-PLA₂ levels were measured in an enzyme-linked immunosorbent assay.

RESULTS

Lp-PLA₂ levels were higher in the CSF group than in the control group (288.6 ± 50.3 versus 141.9 ± 49.7, P < 0.001) and were significantly correlated with the mean coronary artery thrombolysis in myocardial infarction (TIMI) frame count (r = 0.790, P<0.001). Logistic regression analysis showed that high Lp-PLA₂ was independently associated with CSF after adjustment for conventional risk factors (OR = 1.040, CI = 1.022-1.059, P<0.001). Male sex (OR = 2.192, CI = 1.161-4.140, P = 0.016) and hypertension (OR = 1.965, CI = 1.034-3.736, P = 0.039) were also CSF risk factors. Receiver-operating characteristic curve (ROC) analysis showed that Lp-PLA₂ levels can predict CSF severity; the predictive power was higher than the other risk factors.

CONCLUSION

Our study demonstrated that patients with CSF had higher circulating levels of Lp-PLA₂ than normal controls. After adjustment for potential confounders, increased Lp-PLA₂ was independently associated with presence of CSF.

Ventricular Dysfunction in Patients with Coronary Slow-Flow Phenomenon: A Single-center Case-control Study

Background:

Coronary slow-flow phenomenon (CSFP), characterized by delayed distal vessel opacification of contrast, in the absence of significant epicardial coronary stenosis, has effects on exercise capacity and clinical outcomes. The aim of this study was to explore the systolic and diastolic function of patients with CSFP and to compare it with a group of controls with normal coronary anatomy and flow.

Materials and Methods:

In this case–control study, 45 consecutive CSFP patients and 45 age-, body mass index-, and presentation season-matched controls with normal coronary arteries and normal coronary flows were enrolled from Seyyedoshohada Heart Center from March 2015 to March 2016. A transthoracic echocardiography was done by a blinded echocardiographer using both conventional and tissue Doppler imaging techniques.

Results:

Patients with CSFP were more likely to be male (P = 0.006) and smoker (P = 0.02) compared to controls. Other risk factors were not different between the two groups. There were no differences between groups in terms of the peak early (E) and late (A) diastolic velocities, deceleration time, early (E’) and late (A’) peak diastolic velocities at the mitral annulus, and the systolic mitral annular velocity (S’). Global longitudinal strain and peak systolic strain rates was lower in patients with CSFP compared to controls (−16.7% ±2.4% vs. −18.9% ±1.6%, P < 0.001 and 1.10 ± 0.1 vs. 1.24 ± 0.3, P = 0.008, respectively).

Conclusion:

Patients with CSFP showed signs of the left ventricular systolic dysfunction in tissue Doppler echocardiography, which underlines the importance of close follow-up in these patients. Patients with CSFP should be screened for ventricular function preferably by tissue Doppler echocardiography.

Coronary Microvascular Spasm as the Underlying Cause of the Angiographic Slow Flow Phenomenon

Slow coronary flow is frequently seen during angiography in patients with angina and unobstructed coronary arteries. However, the pathophysiology of this finding remains largely unclear. We report a case of a 52-year-old woman with slow coronary flow caused by acetylcholine-induced microvascular spasm, as confirmed by intracoronary flow measurements. (Level of Difficulty: Beginner.).

Suspected Brugada Phenocopy Secondary to Coronary Slow Flow

Brugada syndrome (BrS) is a genetic condition that accentuates the risk of potentially lethal ventricular arrhythmias and sudden cardiac death (SCD) in a structurally normal heart. The Brugada electrocardiographic pattern may manifest separately from the syndrome—this clinical scenario has been described as Brugada phenocopy (BrP). Many etiologies of BrP have been reported, but it has not yet been reported as a result of coronary slow flow (CSF) phenomenon. This case report highlights a suspected coronary slow flow-associated Brugada type 1 electrocardiographic pattern, which subsequently normalized following the institution of guideline-directed medical therapy for acute coronary syndrome.

Cannabis-induced Acute Coronary Syndrome: A Coincidence or Not?

Marijuana, derived from the Cannabis sativa plant, is the most commonly abused illicit drug in the United States. Now, more than ever, due to changing regulations, marijuana is more readily available and is known to be habitually used by millions. The neuropsychiatric effects of marijuana are well-known which include chronic fatigue syndrome and polyphagia. However, marijuana is also known to exert cardiac effects, such as tachycardia, hypotension, and hypertension. Marijuana has also been described in association with atrial fibrillation, ventricular tachycardia, and cardiac arrest. However, acute coronary syndromes, such as myocardial infarction in the setting of marijuana use, is rare. Herein, we present the case of a non-ST-elevation myocardial infarction (NSTEMI) in the setting of marijuana use in a 42-year-old African American male with no significant past medical history who presented with chest pain at rest one hour after smoking marijuana.

QT interval and P wave dispersion in slow coronary flow phenomenon

BACKGROUND

Slow coronary flow (SCF) phenomenon is an angiographic finding which is defined as slow contrast passage through coronary arteries which may predispose patients to serious cardiac complications such as fatal arrhythmias. P-wave and QT-interval dispersion are electrocardiographic findings which are related to atrial fibrillation and ventricular tachyarrhythmias. In the present study, the relation between SCF and presence of P-wave and QT-interval dispersion in electrocardiography has been evaluated.

METHODS

47 patients with normal coronary arteries and SCF and 40 patients with normal coronary artery flow without SCF were enrolled in this case control study. Standard electrocardiogram (ECG) was analyzed for P-wave and QT-interval dispersion. SCF was identified in normal coronary vessels by use of Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) method (TFC > 27). Corrected TIMI frame count (CTFC) of coronary vessels as well as mean CTFC along with QT-interval and P-wave dispersion were compared between 2 groups. The study data were analyzed by SPSS software and P value less than 0.050 was considered to be significant.

RESULTS

QT-interval [76.17 (35.23) ms versus 39.25 (19.26) ms] and P-wave [39.74 (17.48) ms versus 19.50 (8.54) ms] dispersion were significantly higher among patients with SCF phenomenon (P < 0.050). In addition, there was a positive significant linear correlation between TFC and P-wave and QT-dispersion (r = 0.857, r = 0.861, respectively, P < 0.050).

CONCLUSION

According to the results, increasing TFC among patients with SCF will result in P wave and QT interval dispersion and therefore this finding can be considered as an indicative marker for cardiac events.

Subclinical myocardial dysfunction in coronary slow flow phenomenon: Identification by speckle tracking echocardiography

OBJECTIVE

This study aimed to determine whether STE could help detect subclinical myocardial dysfunction in patients with CSFP.

METHODS

Sixty patients with CSFP confirmed by CAG and 51 controls with normal coronary flow were prospectively enrolled. Coronary angiographic data and conventional and speckle tracking echocardiographic parameters of the LV and RV were obtained for every subject.

RESULTS

Compared with controls, CSFP patients presented with higher BMI and TG levels, but lower HDL-C levels. Conventional echocardiographic parameters of biventricular systolic and diastolic function did not differ between the two groups (all P > 0.05). The GLS of the LV and RV was significantly impaired in CSFP patients compared with that in controls (-19.03% vs -21.42%, P < 0.001 and -19.72% vs -22.96%, P = 0.001, respectively). The myocardial impairment pattern of CSFP patients was homogenous in the RV and heterogeneous in the LV, where only endo- and mid-myocardial layers were affected. LV-GLS and RV-GLS were found to be well correlated with mTFC and HDL-C in CSFP groups (r = 0.463 vs r = 0.439; r = -0.569 vs r = -0.552, all P < 0.05). ROC curve analysis demonstrated that LV-GLS-endo had the highest AUC (0.867, P < 0.001) for predicting subclinical myocardial impairment in CSFP patients.

CONCLUSIONS

Subclinical myocardial systolic dysfunction occurs in both ventricles, and GLS could be an effective method to detect early-stage myocardial impairment in patients with CSFP.

Risk factors and angiographic profile of coronary slow flow (CSF) phenomenon in North Indian population: An observational study

Background

“Coronary slow flow’’ (CSF) is delayed vessel opacification in the absence of epicardial stenosis. Studies in different ethnic groups have found variable risk factors associated with CSF.

Aim

of present study was to analyze the risk factors and angiographic profile of CSF in North Indian population, not studied till date.

Methods

40 patients with CSF and 40 controls were studied. CSF was determined quantitatively by thrombolysis in myocardial infarction (TIMI) frame count method. Various clinical risk factors (age, sex, body mass Index (BMI), diabetes, hypertension, dyslipidemia, smoking), hematological and biochemical parameters (hematocrit, platelet count, uric acid, homocysteine, fibrinogen, high sensitivity C reactive protein (hsCRP), glycosylated hemoglobin (HbA1c) were assessed.

Results

Of the 40 patients with CSF, 37 (92.5%) were males. While 20 patients (50%) presented with chronic stable angina, rest 20 (50%) presented with acute coronary syndrome. [15 (37.5%) with unstable angina and 5 (12.5%) with non ST elevation myocardial infarction (NSTEMI)]. Patients with CSF had significantly higher BMI (27.27 ± 2.82 vs. 24.12 ± 2.35, p < 0.001), fibrinogen levels (398.48 ± 120.96 vs. 331.55 ± 162.6, p = 0.04) and smoking (24(60.0%) vs 14(35.0%), p = 0.02). On multivariable regression analysis, only BMI was found to have an independent association with CSF (odds ratio 1.613, 95% confidence interval 1.265–2.057, p < 0.001).

Conclusion

This is the first study to analyze clinical presentation, angiographic profile and risk factors associated with CSF in North Indian population. In this study, we found only BMI to have an independent association with CSF.

Transcriptional activity of tumor necrosis factor-alpha gene in peripheral blood mononuclear cells in patients with coronary slow flow

BACKGROUND

Coronary slow flow (CSF), an angiographic phenomenon that is characterized by a delayed coronary blood flow in the absence of obstructive coronary artery stenosis, is known as a disorder of the coronary microcirculation. Inflammation has an important role in the vascular hemostasis and endothelial dysfunction especially regarding monocyte adhesion and infiltration. Pro-inflammatory cytokines released by inflammatory cells result in endothelial cell dysfunction and cardiovascular diseases. It has been demonstrated that tumor necrosis factor-alpha (TNF-α) mainly influences the vascular homeostasis and endothelial dysfunction. In the present enquiry the transcriptional activity of TNF-α gene in peripheral blood mononuclear cells (PBMCs) of patients with CSF was compared with healthy controls in order to further survey the role of TNF-α in pathophysiology of CSF.

METHODS

The study was carried out on 30 patients with CSF and 30 matched healthy controls. To analysis gene expression of TNF-α, total mRNA was isolated from PBMCs. The quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) was used to compare the transcriptional activity of TNF-α gene between patients with CSF and controls.

RESULTS

The mean ± standard error of mean of fold in CSF patients and controls were 0.20 ± 0.04 and 1.38 ± 0.27, respectively. The mRNA mean expressions of TNF-α (fold) were different in tested groups, which indicated a significant decrease in TNF-α in patients with CSF group (P = 0.0001).

CONCLUSION

Expression of TNF-α was decreased in patients with CSF. Changes in TNF-α expression suggest a potential role for altered immune function in the pathophysiology of CSF.