Slow coronary flow phenomenon and increased platelet volume indices

Understanding the pathogenesis of coronary slow flow: Recent advances

Coronary slow flow is taken to be indicative of delayed filling of terminal vessels of the coronary arteries in the absence of coronary stenosis, as detected using coronary angiography. Patients suffering from coronary slow flow typically experience recurrent chest pain, thereby markedly affecting their quality of life. The etiology and pathogenesis of coronary slow flow, which is gradually attracting clinical attention, have yet to be sufficiently established, although it is currently believed that they may be associated with endothelial dysfunction in the coronary arteries, inflammatory response, abnormalities in microvascular reserve function, subclinical atherosclerosis, blood cell and platelet abnormalities, and genetic factors. In this review, we provide a brief overview of recent progress in research on the pathogenesis of coronary slow flow with a view toward elucidating the possible underlying pathogenesis and identify targets and directions for the treatment of this condition.

Dysregulation of LncRNAs ANRIL, MALAT1, and LINC00305 in Coronary Slow Flow Patients: Implications for Inflammation and Endothelial Dysfunction

Coronary Slow Flow (CSF) is observed in individuals who experience delayed blood supply in the coronary arteries. Inflammation and endothelial dysfunction may play a role in the etiology and development of CSF. The current investigation aimed to compare the expression of specific long noncoding RNAs (lncRNAs) associated with endothelial dysfunction and inflammation in CSF patients. This case‒control study enrolled 72 CSF patients and 71 healthy individuals. Blood samples were collected, and serum marker levels were measured. The expression levels of lncRNAs ANRIL, MALAT1, and LINC00305 in peripheral blood mononuclear cells (PBMCs) were assessed using real-time Polymerase Chain Reaction (PCR). All statistical analyses were performed using SPSS 22, with the significance level set at P < 0.05. The study revealed that the relative expression of MALAT1 and LINC00305 was significantly lower in the CSF group (p < 0.01), whereas ANRIL was expressed at higher levels (p < 0.0001). The areas under the ROC curves (AUCs) for MALAT1, LINC00305, and ANRIL were 0.64, 0.66, and 0.75, respectively. Notably, the expression level of LINC00305 exhibited an inverse correlation with CSF incidence (OR: 0.83, p: 0.008) in contrast to that of ANRIL (OR: 1.43, p < 0.0001). Additionally, compared to those in the control group, the average BMI, WBC, RBC, Hb, LDH, LDL, FBS, and percentage of neutrophils in the CSF group were significantly greater (p< 0.05). lncRNA ANRIL is upregulated in CSF patients, whereas MALAT1 and LINC00305 are downregulated. Dysregulation of ANRIL, MALAT1, and LINC00305 may serve as diagnostic and predictive factors for CSF leakage.

Complete Blood Count-Derived Indices as Prognostic Factors of 5-Year Outcomes in Patients With Confirmed Coronary Microvascular Spasm

Background

Coronary microcirculatory dysfunction is a meaningful factor in the development of ischemic heart disease. We investigated the relationship between coronary microvascular spasm and complete blood count indices.

Methods

Between 2010 and 2013, we performed acetylcholine test (AChT) in subjects with suspicion of angina evoked by epicardial coronary spasm or coronary microvascular spasm according to COVADIS criteria. We administered acetylcholine in increasing doses of 25, 50, and 75 μg into the right coronary artery and 25, 50, and 100 μg into the left coronary artery. Patients were followed up for 60 months.

Results

In total, 211 patients (60.5 ± 7.8 years, 67.8% women) were included in the study. The AChT revealed angina due to epicardial coronary spasm in 99 patients (46.9%) and coronary microvascular spasm in 72 (34.1%). White blood cell (WBC), red blood cell distribution width (RDW), platelets (PLT), mean platelet volume (MPV), and platelet distribution width (PDW) values were significantly higher in patients with coronary microvascular spasm than in patients from the other two groups, i.e., epicardial coronary spasm and negative AChT. PDW showed the highest sensitivity (65%) and specificity (72%) at the cutoff value of 15.32% [area under the curve, 0.723; 95% confidence interval (CI) 0.64-0.83; P < 0.001]. Independent risk factors for coronary microvascular spasm diagnosis using AChT were as follows: female sex (OR, 1.199), PDW (OR, 2.891), and RDW (OR, 1.567).

Conclusion

PDW and RDW are significantly associated with the diagnosis of coronary microvascular spasm in patients undergoing AChT as well as with poor prognosis in such patients at 5 years.

Retinal fluorescein angiography: A sensitive and specific tool to predict coronary slow flow

Background

Obstructive coronary artery disease (OCAD) and coronary slow flow (CSF) are frequent angiographic findings for patients that have chest pain and require frequent hospital admission. The retina provides a window for detecting changes in microvasculature relating to the development of cardiovascular diseases such as arterial hypertension or coronary heart disease.

Objectives

To assess the coronary and ocular circulations in patients with CSF and those with obstructive coronary artery disease.

Methods

A prospective study was conducted over 3.5 years, included a total of 105 subjects classified to 4 groups: Group I (OCAD): Included 30 patients with obstructive coronary artery disease, group II (CSF): Included 30 patients with coronary slow-flow, group III (Control 1): Included 30 healthy control persons and group IV (Control 2): Included 15 patients indicated for coronary angiography that proved normal. All participants were subjected to coronary angiography (except control group 1), ophthalmic artery Doppler for measuring Pulsatility index (PI) and resistivity index (RI) and Fluorescence angiography of retinal vessels.

Results

Patients with CSF showed slow flow retinal circulation (microcirculation) evidenced by prolonged fluorescein angiography (Arm-retina time [ART] & Arterio-venous Transit time [AVTT]). Ophthalmic artery Doppler measurements (RI & PI) were significantly delayed in OCAD and CSF patients. There was significant positive correlation between TIMI frame count in all subjects and ART, AVTT, PI, RI and Body Mass Index. Using ART cutoff value of >16 s predicted CSF with sensitivity and specificity of 100%, meanwhile AVTT of >2 s predicted CSF with a sensitivity 96.7% and specificity of 93.3.

Conclusion

Both delayed arm-retina time and retinal arterio-venous transit times can accurately predict coronary slow-flow.

Clinical and laboratory predictors of coronary slow flow in coronary angiography

Background:

The coronary slow-flow phenomenon (CSFP) is a multifactorial angiographic finding with no established pathogenesis.

Objective:

To investigate the role of clinical profile and laboratory findings in patients with CSFP.

Methods:

We prospectively recruited 69 patients with angiographically diagnosed CSFP and compared them with 88 patients with normal coronary flow. Demographic information, comorbidities and laboratory analysis, including complete blood count with differential, lipid profile and serum biochemical analysis, were documented and compared in univariate and multivariate analyses.

Results:

Patients with CSFP were more likely to be male and active smokers. Total cholesterol, triglyceride, hemoglobin and hematocrit, platelet count, mean platelet volume, platelet distribution width and red cell distribution width (RDW) were all higher in patients with CSFP. In multivariate regression analysis, including smoking, total cholesterol, hematocrit, fasting blood glucose and red cell distribution width, except fasting blood glucose, all variables were independently associated with CSFP. Receiver operating characteristic curve analysis revealed a cut-off point of 13.05% for RDW with a sensitivity of 74.6% and a specificity of 77.3% (p<0.001, AUC = 0.802) A cut-off value of 11.35% for PDW had a 89.9% sensitivity and 98.9% specificity for the prediction of CSFP (p<0.001, AUC = 0.970)

Conclusion:

The changes of circulating blood cell components in patients with CSFP may be indicative of underlying inflammation and endothelial dysfunction that should be investigated in experimental studies.