Examination of the microcirculation damage in smokers versus nonsmokers with vasospastic angina pectoris

A Rare Encounter: Unstable Vasospastic Angina Induced by Thyrotoxicosis

Coronary artery vasospasm plays a crucial role in the prevalence of unstable angina. Despite common misdiagnosis, there is limited evidence on this topic. Here, we present a rare case of unstable vasospastic angina in a female with severe thyrotoxicosis. Case Report: A 62-year-old female patient was admitted to the cardiac intensive care unit due to crushing chest pain at rest. The patient exhibited ischemic changes on the ECG with a normal troponin I level. Recurrent chest pain prompted urgent coronary angiography, revealing generalized vasospasm of all coronary artery branches including the left main coronary artery. Intracoronary nitroglycerin injection partially alleviated the vasospasm; however, there was a persistent stenosis in the left main artery. Subsequent intravascular ultrasound demonstrated an anatomically normal left main artery. Post-procedure, laboratory tests revealed undetectable levels of thyroid-stimulating hormone and thyroid hormones above the detectable level. The patient was initiated on methimazole and discharged symptom-free, expecting a good prognosis under conservative management. Conclusions: Clinically significant coronary vasospasm triggered by thyrotoxicosis remains a rarity in clinical practice, often posing diagnostic challenges. This case emphasizes the significance of intracoronary nitroglycerin and intravascular ultrasound in discerning the etiology of coronary lesions seen on angiography. We advocate for these techniques to optimize invasive coronary artery diagnostics, enabling the selection of the appropriate treatment strategies and improving long-term prognosis.

Smoking, alcohol and opioids effect on coronary microcirculation: an update overview

Smoking, heavy alcohol drinking and drug abuse are detrimental lifestyle factors leading to loss of million years of healthy life annually. One of the major health complications caused by these substances is the development of cardiovascular diseases (CVD), which accounts for a significant proportion of substance-induced death. Smoking and excessive alcohol consumption are related to the higher risk of acute myocardial infarction. Similarly, opioid addiction, as one of the most commonly used substances worldwide, is associated with cardiac events such as ischemia and myocardial infarction (MI). As supported by many studies, coronary artery disease (CAD) is considered as a major cause for substance-induced cardiac events. Nonetheless, over the last three decades, a growing body of evidence indicates that a significant proportion of substance-induced cardiac ischemia or MI cases, do not manifest any signs of CAD. In the absence of CAD, the coronary microvascular dysfunction is believed to be the main underlying reason for CVD. To date, comprehensive literature reviews have been published on the clinicopathology of CAD caused by smoking and opioids, as well as macrovascular pathological features of the alcoholic cardiomyopathy. However, to the best of our knowledge there is no review article about the impact of these substances on the coronary microvascular network. Therefore, the present review will focus on the current understanding of the pathophysiological alterations in the coronary microcirculation triggered by smoking, alcohol and opioids.

A silent myocardial infarction with normal coronary arteries associated with Graves' disease

Acute myocardial infarction (AMI) is a scarce but fatal complication in Graves' disease (GD). Silent myocardial infarction (MI) associated with GD has never been reported. A 37-year-old male patient was admitted due to poorly controlled hyperthyroidism and persistent fever. But the patient did not complain of chest pain on admission. The electrocardiogram (ECG) showed Q waves and ST-segment elevations. Cardiac troponin I (cTnI) was sharply increased. He was qualified to an emergency coronary angiography which showed normal coronary arteries without any stenosis. The potential mechanisms for AMI with angiographically normal coronary arteries in the setting of hyperthyroidism may be attributed to the hyper-metabolic state due to thyrotoxicosis, severe vasospasm in coronary artery, coagulation abnormalities, and the inflammatory/autoimmune milieu. In conclusion, patients with GD-associated silent MI are unusual. Early recognition and diagnosis by clinicians provide a better prognosis. This case demonstrates the importance of ECG and cTnI screening among GD patients.

The complex P2X7 receptor/inflammasome in perivascular fat tissue of heavy smokers

OBJECTIVE

Smoking is a recognized cardiovascular risk factor. Perivascular visceral adipose tissue (PVAT) is a source of inflammatory molecules, thus contributing to atherosclerosis progression. The P2X7 receptor (P2X7 R)-inflammasome complex, crucial in determining IL-1β and IL-18 release, participates in this scenario. We evaluated whether smoking might affect the PVAT inflammatory phenotype and explored the putative role of the axis P2X7 R-inflammasome in this picture.

SUBJECTS AND METHODS

TNFα, IL-6, RBP4, MCP-1, as well as P2X7 R and inflammasome components NLRP3, ASC, caspase-1 and IL-1β and IL-18 expression was determined in adipocytes isolated by PVAT of healthy smokers (Smok) and nonsmokers (No-Smok) subjects. Plasma and culture medium levels of these cytokines were also determined.

RESULTS

Perivascular adipose tissue of Smok had a higher expression of P2X7 R and inflammasome components; via P2X7 R activation, it released more IL-1β and IL-18, whose serum levels were also higher in Smok than in No-Smok. Linear correlations of NLRP3 with P2X7 R and IL-18 expression and release emerged. Smok also had a higher PVAT expression of the chemotactic factor MCP-1. However, no difference was observed in the PVAT expression of genes more strictly related to insulin resistance, like TNFα, RBP4, IL-6; this was coupled with similar plasma levels of TNFα and RBP4 in the two groups.

CONCLUSION

Smoking contributes to the pro-inflammatory status of the PVAT by enhancing expression and activity of the P2X7 R-inflammasome complex; the effect on adipocytokines more related to insulin resistance and metabolic abnormalities appears trivial.

Evaluation of coronary microvascular function in patients with vasospastic angina

AIM: To investigate endothelium-dependent and -independent coronary microvascular functions in patients with vasospastic angina (VSA).

METHODS: Thirty-six patients with VSA (30 men and 6 women; mean age, 58 years) were enrolled in this study. VSA was defined as ≥ 90% narrowing of the epicardial coronary arteries on angiography performed during a spasm provocation test, presence of chest pain, and/or ST-segment deviation on an electrocardiogram (ECG). Patients (n = 36) with negative spasm provocation test results and those matched for age and sex were enrolled as a control group (nonVSA group). Low-dose acetylcholine (ACh; 3 μg/min) was infused into the left coronary ostium for 2 min during the spasm provocation test. Following the spasm provocation test, nitroglycerin (0.2 mg) was administered intracoronally. Coronary blood flow (was calculated from quantitative angiography and Doppler flow velocity measurements, and the coronary flow reserve was calculated as the ratio of coronary flow velocity after injection of adenosine triphosphate (20 μg) to the baseline value. Changes in the coronary artery diameter in response to ACh and nitroglycerin infusion were expressed as percentage changes from baseline measurements.

RESULTS: Body mass index was significantly lower in the VSA group than in the nonVSA group. The frequency of conventional coronary risk factors and the rate of statin use were similar between the 2 groups. The left ventricular ejection fraction as evaluated by echocardiography was similar between the 2 groups. The duration of angina was 9 ± 2 mo. The results of blood chemistry analysis were similar between the 2 groups. Low-dose ACh did not cause coronary spasms. The change in coronary artery diameter in response to ACh was lower in the VSA group (-1.4% ± 9.3%) than in the nonVSA group (3.1% ± 6.5%, P < 0.05), whereas nitroglycerin-induced coronary artery dilatation and coronary blood flow increase in response to ACh or coronary flow reserve did not differ significantly between the 2 groups.

CONCLUSION: These findings suggest that microvascular coronary function may be preserved despite endothelial dysfunction of the epicardial coronary arteries in patients with VSA.

The impact of aging and atherosclerotic risk factors on transthoracic coronary flow reserve in subjects with normal coronary angiography

Age may affect coronary flow reserve (CFR) especially in subjects with atherosclerotic risk factors (ARFs). The aim of this prospective, multicenter, observational study was to determine the effects of aging on CFR in patients with normal epicardial coronary arteries and ARFs. Three-hundred-thirty-five subjects (mean age = 61 years) with at least one ARF but normal coronary angiography underwent high-dose dipyridamole stress-echo with Doppler evaluation of left anterior descending artery. CFR was calculated as the ratio between hyperemic and resting coronary diastolic peak velocities. Patients were divided in age quartiles. CFR was progressively reduced with aging (1st quartile: 3.01 ± 0.69, 4th quartile: 2.39 ± 0.49, p < 0.001). This was mainly due to a gradual increase of resting velocities (1st quartile = 26.3 ± 6.1 cm/s, 4th quartile = 30.2 ± 6.4 cm/s, p < 0.001) while the reduction of hyperemic velocities remained unaffected (1st quartile = 77.7 ± 18.9 cm/s, 4th quartile = 70.9 ± 18.4 cm/s, NS). When age quartiles and ARFs were entered into a regression model, third and fourth age quartile (p < 0.0005 and p < 0.0001 respectively), left ventricular mass index (p < 0.0001), diastolic blood pressure (p < 0.001), total cholesterol (p < 0.002), fasting blood glucose (p < 0.01) and male gender (p < 0.05) were independent determinants of CFR in the whole population. Aging reduces coronary flow reserve in patients with angiographically normal coronary arteries due to a gradual increase of resting coronary flow velocity. CFR is also affected by atherosclerotic risk factors and left ventricular hypertrophy.

Acute myocardial infarction as the first presentation of thyrotoxicosis in a 31-year old woman - case report

A 31-year old woman, previously fit & well was admitted with pressing retrosternal chest pain and palpitations of sudden onset. Her body weight was normal (BMI 20.5 kg/m²) and there was no significant family history of cardiac disease. She smoked, however, about 15 cigarettes a day and she had been taking combined oral contraceptive pill (Cilest^®) for about three years. On admission she appeared sweaty and in pain, blood pressure 130/70 mmHg, heart rate about 110/min, mild lid-lag sign. Heart sounds were normal and chest was clear. ECG revealed 2-3 mm ST segment elevations in II, III, aVF as well as V2 to V5. Troponin I was raised and she was qualified to an emergency coronary angiography. This revealed a massive spasm of left anterior descending (LAD) coronary artery that responded to intracoronary glyceryl trinitrite administration, however, with the presence of critical narrowing of the LAD apical segment with possible superimposed thrombus. Cardiac ultrasound revealed akinesis of 1/2 of apical area consistent with myocardial infarction

Treatment and progress

She was started on Aspirin, Simvastatin, and Diltiazem, but continued to have persistent tachycardia and tremor. Thyroid function tests were ordered and showed thyrotoxicosis [free T4-46.9 pmol/l (ref. range 9-25), free T3-11.9 pmol/l (2-5), TSH - 0.02 mIU/l (0.27-4.2)]. She was referred for an endocrine opinion and started on Thiamazole. Other investigations revealed elevated anti-TPO and anti-TSH receptor antibodies consistent with Graves' disease. Thrombophilia screen was negative. She had remained euthyroid on a "block & replace" regimen (Thiamazole plus L-Thyroxine) that was discontinued after 18 months. She denies any anginal symptoms, but continues to smoke against medical advice.

Conclusions

Our case highlights the possibility of development of an acute myocardial infarction in a young subject with thyrotoxicosis. We speculate that patient's smoking habit combined with subtle thyrotoxicosis-induced prothrombotic state and/or coronary-artery spasm had lead to the above-mentioned acute coronary event.

Combination of variant and microvascular angina

Prinzmetal's variant angina (VA) and cardiac syndrome X (CSX) are two distinct, usually easily recognizable, forms of angina syndromes, caused by epicardial spasm, usually responsible for transient transmural myocardial ischemia at rest and by coronary microvascular dysfunction (CMVD), usually responsible for effort induced subendocardial ischemia, respectively. In this article we report clinical evidence in three patients of the simultaneous occurrence of angina episodes typical of both VA and CSX, suggesting that common pathogenetic factors may be responsible for clinical manifestations both of functional macrovascular and microvascular coronary artery abnormalities in some angina patients.

Assessment of endothelial (dys)function in atrial fibrillation

Atrial fibrillation (AF) is associated with an increased risk of mortality and morbidity from stroke and thromboembolism. Endothelial damage or dysfunction may contribute to this increased risk of thromboembolism via the mediation of a prothrombotic or hypercoagulable state. However, the precise pathophysiological mechanism(s) relating endothelial (dys)function to AF and thromboembolism are yet to be fully elucidated. This review article aims to provide a comprehensive overview of endothelial (dys)function and AF, as well as the merits and limitations of the different methods used to assess endothelial function in AF.

Coronary endothelial dysfunction and impaired microcirculation response to atrial natriuretic peptide in hyperinsulinemia

Endothelial dysfunction occurs in hyperinsulinemia (HI). Coronary microcirculation responses to vasoactive agents are examined in 57 patients with angiographically normal coronary arteries. Patients were divided into 2 groups, 37 with normoinsulinemia (NI) and 20 with HI based on results of a 75-g oral glucose tolerance test. Epicardial artery vasoactivity in response to acetylcholine chloride is measured to assess endothelial function. Coronary microcirculation function is evaluated by intracoronary administration of 50 microg of adenosine triphosphate, 1 mg of isosorbide dinitrate, and 0.05 mg/kg of atrial natriuretic peptide. Epicardial artery vasoconstriction in response to 100 microg of acetylcholine is mildly reduced in HI (P = .04). Coronary flow reserve in response to adenosine triphosphate in NI is similar to that in HI. In NI, the resting mean (SD) peak velocity in response to isosorbide dinitrate (40.7 [10.9] cm/s) vs atrial natriuretic peptide (39.6 [10.9] cm/s) is similar. In contrast, the resting mean (SD) peak velocity in response to atrial natriuretic peptide (31.3 [9.3] cm/s) vs isosorbide dinitrate (43.5 [10.0] cm/s) in HI is statistically significantly blunted (P < .001). Atrial natriuretic peptide may have a pathologic effect on coronary microcirculation even in mild endothelial dysfunction among patients with HI.