Comparison of morphologic findings obtained by optical coherence tomography in acute coronary syndrome caused by vasospasm and chronic stable variant angina

Pathological findings at invasive assessment in MINOCA: a systematic review and meta-analysis

BACKGROUND

Pathological mechanisms of myocardial infarction with non-obstructive coronary arteries (MINOCA) are heterogeneous, with an unknown impact on prognosis, and often remain unrecognised in clinical practice. This study aimed to evaluate the prevalence and prognostic impact of pathological findings by invasive coronary angiography (ICA), optical coherence tomography (OCT), and coronary function testing in MINOCA.

METHODS

Studies published until August 2023 were searched on PubMed and SCOPUS and included if reporting the prevalence of patients with non-obstructive coronary arteries (NObs-CA; 1-49% coronary stenosis) versus normal coronary arteries (NCA; 0% coronary stenosis) by ICA, pathological findings by OCT, and/or coronary vasomotor tests in MINOCA. Newcastle-Ottawa Scale was used for quality assessment. The pooled prevalence of pathological findings was estimated with random-effects models. Pooled risk ratios (RRs) with 95% CIs of all-cause death, MI and the composite of both in patients with NObs-CA versus NCA were calculated at short-term (<1 month), 1-year and long-term follow-up (> 1 year).

RESULTS

Forty-five studies including 17 539 patients were analysed. The pooled prevalence of NObs-CA at ICA was 53% (95% CI 0.47 to 0.60). OCT showed acute pathological findings in 62% (95% CI 0.44 to 0.78) of patients and coronary vasomotor tests were positive in 49% (95% CI 0.31 to 0.67). NObs-CA compared with NCA was associated with an increased 1-year risk of all-cause death or MI (RR=1.49 (95% CI 1.17 to 1.90)) and MI alone (RR=1.80 (95% CI 1.26 to 2.59)), whereas the risk of all-cause death was comparable. Similar results were seen at long-term, but not at short-term follow-up.

CONCLUSIONS

Stratification of MINOCA into NObs-CA versus NCA has prognostic value. OCT and vasospasm testing, often informative about the pathological mechanism of MINOCA, should be part of an invasive diagnostic algorithm.

PROSPERO REGISTRATION NUMBER

CRD42023468183.

Cellular Mechanisms of Coronary Artery Spasm

Coronary artery spasm (CAS) is a reversible phenomenon caused by spontaneous excessive vascular smooth muscle contractility and vascular wall hypertonicity, which results in partial or complete closure of the lumen of normal or atherosclerotic coronary arteries. The clinical picture of CAS includes chest discomfort which is similar in quality to that of stable effort angina. Mechanisms underlying the development of CAS are still unclear. CAS certainly is a multifactorial disease. In this review, we paid attention to the role of the main pathophysiologic mechanisms in CAS: endothelial dysfunction, chronic inflammation, oxidative stress, smooth muscle hypercontractility, atherosclerosis and thrombosis, and mutations leading to deficient aldehyde dehydrogenase 2 (ALDH2) activity. These findings might shed novel insight on the underlying mechanisms and identify potential diagnostic and therapeutic targets for cardiovascular diseases in the future.

The role of myocardial work in evaluating coronary microcirculation of STEMI patients after percutaneous coronary intervention

BACKGROUND

Despite of restoring epicardial infarct-related artery(IRA) patency after myocardial infarction, microvascular reperfusion were not achieved sometimes, and the deterioration of myocardial perfusion persists in a considerable number of patients. This phenomenon is known as microvascular obstruction (MVO). MVO is often observed in ST-Segment Elevation Myocardial Infarction(STEMI) patients, even if percutaneous coronary intervention (PCI) was successful. In addition, some evidence has indicated that the presence of MVO predicted poor clinical outcomes independent of myocardial infarct size. Noninvasive as well as invasive modes for assessing microvascular perfusion(MVP) are complex, time consuming, and expensive have, there is yet no simple method available at present to assess coronary microcirculation. In this research, we attempt to evaluate the usefulness of left ventricular myocardial work (LVMW), a new index of myocardial performance, for the assessment of MVP in STEMI patients after PCI.

METHODS

Forty-seven patients with STEMI treated by PCI were enrolled and underwent a transthoracic doppler echocardiography (TTE) within 24-72 hours after PCI. IRA were left anterior descending (LAD) artery (29,62%), left circumflex (LCX) artery(9,19%), right coronary artery (RCA) (9,19%) respectively. Myocardial contrast echocardiography (MCE) was used to evaluate MVP after PCI, then perfusion score index (PSI) was calculated referring to whether the ultrasonic enhancing agents was replenishment or not. Patients were divided into normal MVP and impaired MVP group according to PSI. Left ventricular global longitudinal strain (GLS) was generated by speckle tracking echocardiography(STE) and pressure-strain loops (PSLs) was used to generate global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). GLS and the MW parameters (GWI, GCW, GWW, GWE) were compared between groups. Receiver operating characteristic (ROC) curves were calculated by plotting sensitivity versus (1-specificity), allowing calculation of the area under the curve (AUC) and the identification of LVMW parameters and GLS cutoff thresholds that best identify STEMI patients with impaired MVP after PCI.

RESULTS

In this study, a statistically significant difference was observed in GWI (1163±405 mm Hg% vs 1617±363 mm Hg%), GCW (1296±430 mm Hg% vs 1789±406 mm Hg%), GWE (83±8.52% vs 90±5.58%) and GLS (11.56±3.29 vs 16.65±3.59) between impaired MVP group and normal MVP group. However, there is no statistical significance difference in left ventricular ejection fraction (LVEF), and GWW. ROC analysis revealed that GCW (cut-off value: 1326 mm Hg%, AUC: .80, sensitivity: 95% and specificity: 56%), GWI (cut-off value: 1281 mm Hg%, AUC: .81, sensitivity: 90% and specificity: 70%), GWE (cut-off value: 90%, AUC: .77, sensitivity: 65% and specificity: 78%) and GLS (cut-off value: 12.5, AUC: .86, sensitivity: 90% and specificity: 67%) have appreciable AUC, sensitivity, and specificity to identify STEMI patients with impaired MVP after PCI.

CONCLUSION

Measuring LVMW indices of STEMI patients after PCI may add adjuvant value for the assessment of MVP.

OCT Findings in MINOCA

Myocardial infarction with non-obstructive coronary artery disease (MINOCA) is a working diagnosis for patients presenting with acute myocardial infarction without obstructive coronary artery disease on coronary angiography. It is a heterogenous entity with a number of possible etiologies that can be determined through the use of appropriate diagnostic algorithms. Common causes of a MINOCA may include plaque disruption, spontaneous coronary artery dissection, coronary artery spasm, and coronary thromboembolism. Optical coherence tomography (OCT) is an intravascular imaging modality which allows the differentiation of coronary tissue morphological characteristics including the identification of thin cap fibroatheroma and the differentiation between plaque rupture or erosion, due to its high resolution. In this narrative review we will discuss the role of OCT in patients presenting with MINOCA. In this group of patients OCT has been shown to reveal abnormal findings in almost half of the cases. Moreover, combining OCT with cardiac magnetic resonance (CMR) was shown to allow the identification of most of the underlying mechanisms of MINOCA. Hence, it is recommended that both OCT and CMR can be used in patients with a working diagnosis of MINOCA. Well-designed prospective studies are needed in order to gain a better understanding of this condition and to provide optimal management while reducing morbidity and mortality in that subset patients.

Myocardial infarction with non-obstructive coronary arteries (MINOCA): Intracoronary imaging-based diagnosis and management

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is defined by clinical evidence of myocardial infarction (MI) with normal or near-normal coronary arteries on angiography. This condition is present in about 5% to 25% of patients presenting with acute coronary syndromes. MINOCA is a working diagnosis. Current guidelines and consensus recommend identification of underlying causes of MINOCA in order to optimize treatment, improve prognosis, and promote prevention of recurrent myocardial infarction. An accurate evaluation of patient history, symptoms and use of invasive and non-invasive imaging should lead to identification of epicardial or microvascular causes of MINOCA and differentiation from non-ischemic myocardial injury due to both cardiac (e.g. myocarditis) and non-cardiac disease (e.g. pulmonary embolism). In this review, we highlight the role of coronary imaging in differential diagnosis of patients presenting with MINOCA. Intravascular ultrasound and optical coherence tomography are well known technologies used in different settings from acute to chronic coronary syndromes. In MINOCA patients, coronary imaging could help to identify pathological alterations of the epicardial vessels that are not visible by coronary angiography such as plaque disruption, coronary dissection, coronary thromboembolism, coronary spasm, and coronary artery disease in patients presenting with takotsubo syndrome. In future, the widespread use of these technologies, in the right clinical context, could lead to optimization and personalization of treatment, and to better prognosis of patients presenting with MINOCA.

Optical coherence tomography: fundamentals and clinical utility

Although coronary angiography is the standard method employed to assess the severity of coronary artery disease and to guide treatment strategies, it provides only 2D image of the intravascular lesions. In contrast, intravascular imaging modalities such as optical coherence tomography (OCT) produce cross-sectional images of the coronary arteries at a far greater spatial resolution, capable of accurately determining vessel size as well as plaque morphology, eliminating many of the disadvantages inherent to angiography. This review will discuss the role of OCT in the catherization laboratory for the assessment and management of coronary disease.

Troponin-Positive Non-Obstructive Coronary Arteries and Myocardial Infarction with Non-Obstructive Coronary Arteries: Definition, Etiologies, and Role of CT and MR Imaging

In approximately 10% of patients with acute myocardial infarction (MI), angiography does not reveal an obstructive coronary stenosis. This is known as myocardial infarction with non-obstructive coronary arteries (MINOCA), which has complex and multifactorial causes. However, this term can be confusing and open to dual interpretation, because MINOCA is also used to describe patients with acute myocardial injury caused by ischemia-related myocardial necrosis. Therefore, with regards to this specific context of MINOCA, the generic term for MINOCA should be replaced with troponin-positive with non-obstructive coronary arteries (TpNOCA). The causes of TpNOCA can be subcategorized into epicardial coronary (causes of MINOCA), myocardial, and extracardiac disorders. Cardiac magnetic resonance imaging can confirm MI and differentiate various myocardial causes, while cardiac computed tomography is useful to diagnose the extracardiac causes.

Intracoronary Optical Coherence Tomography 2018: Current Status and Future Directions

The advent of intravascular imaging has been a significant advancement in visualization of coronary arteries, particularly with optical coherence tomography (OCT) that allows for high-resolution imaging of intraluminal and transmural coronary structures. Accumulating data support a clinical role for OCT in a multitude of clinical scenarios, including assessing the natural history of atherosclerosis and modulating effects of therapies, mechanisms of acute coronary syndromes, mechanistic insights into the effects of novel interventional devices, and optimization of percutaneous coronary intervention. In this state-of-the-art review, we provide an overview of the published data on the clinical utility of OCT, highlighting the areas that need further investigation and the current barriers for further adoption of OCT in interventional cardiology practice.

Clinical efficacy of aspirin with identification of intimal morphology by optical coherence tomography in preventing event recurrence in patients with vasospasm-induced acute coronary syndrome

Using optical coherence tomography (OCT), we found that there were morphological differences in the coronary intima between patients with vasospasm-induced acute coronary syndrome (VACS) and those with stable variant angina. We investigated whether aspirin use would protect against chest pain recurrence in patients with VACS. A retrospective cohort study was performed. Patients with ST-segment elevation who were confirmed to have VACS by a provocation test were included. OCT was performed at the index event and when chest pain recurred to assess intimal morphology. Chest pain recurrence was defined as the first revisit to the emergency room with angina. Propensity score matching was performed between the aspirin and non-aspirin groups. For 48 months, 154 patients were followed (77 patients in each group). The baseline characteristics and OCT findings were well balanced between the two groups after propensity score matching. Myocardial infarction (17 vs. 3%, p = 0.003) and chest pain recurrence (26 vs. 9%, p = 0.006) occurred more frequently in the non-aspirin group than in the aspirin group. Multiple Cox regression analysis showed that aspirin use was a significant predictor of lower risk of myocardial infarction [hazard ratio (HR) 0.13; 95% confidence interval (CI) 0.03-0.61] and chest pain recurrence (HR 0.33; 95% CI 0.12-0.71) during the follow-up period, after adjustments for relevant covariates including OCT findings. The use of aspirin may have a preventive effect on myocardial infarction and chest pain recurrence in patients with VACS. Randomized controlled trials are necessary to confirm the result.

Vasospastic myocardial infarction complicated with bilateral femoral arteries vasospasm

Coronary vasospasm is an infrequent cause of acute coronary syndrome. Additionally, femoral artery spasm is not frequently encountered clinically. Here we present a case of a patient with an acute ST segment elevation myocardial infarction, secondary to a documented right coronary artery vasospasm, complicated with left coronary artery and femoral artery vasospasm. Intravenous ultrasound showed calcification at the sites of spasm. This case report indicates that coronary vasospasm should be regularly considered as part of the work up of myocardial infarction.

Two-dimensional myocardial deformation in coronary vasospasm-related Takotsubo cardiomyopathy: A case report of a serial echocardiographic study

RATIONALE

Although transient reduction in the left ventricular ejection fraction is characteristic of Takotsubo cardiomyopathy, little is known about the time-course changes of myocardial deformation in coronary vasospasm-related Takotsubo cardiomyopathy.

PATIENT CONCERNS

We retrospectively analyzed the time-course changes in left ventricle, right ventricle, and left atrium strain values in a patient with coronary vasospasm-related Takotsubo cardiomyopathy. We found that not only left ventricular strain but also left atrial strain was abnormal during acute Takotsubo cardiomyopathy due to coronary vasospasm. Right ventricular free wall strain was normal.

DIAGNOSES

Coronary vasospasm-related Takotsubo cardiomyopathy.

INTERVENTIONS

A serial echocardiographic study.

OUTCOMES

The left ventricular strain was still subnormal despite a normalized left ventricular ejection fraction 2 months later. The left atrial strain was normal when the left ventricular ejection fraction normalized.

LESSONS

From this limited experience, it is suggested that echocardiographic myocardial deformation analysis can provide more information than the standard ejection fraction in evaluating myocardial contractile function.

A case of recurrent unstable angina - Insight from optical coherence tomography imaging

Intimal tear is a rare cause of ACS and is angiographically indistinguishable. OCT provides unprecendented insight to the mechanism of ACS with its near tissue level definition. This is a case of unstable angina with non-significant RCA lesion. OCT showed intimal tear/flaps with evidence of thrombi, thus clinching the diagnosis.

Intravascular ultrasound observation of the mechanism of no-reflow phenomenon in acute myocardial infarction

Objective

To study the mechanism of the no-reflow phenomenon using coronary angiography (CAG) and intravascular ultrasound (IVUS).

Methods

A total of 120 patients with acute myocardial infarction (AMI) who successfully underwent indwelling intracoronary stent placement by percutaneous coronary intervention (PCI). All patients underwent pre- and post-PCI CAG and pre-IVUS. No-reflow was defined as post-PCI thrombolysis in myocardial infarction (TIMI) grade 0, 1, or 2 flow in the absence of mechanical obstruction. Normal reflow was defined as TIMI grade 3 flow. The pre-operation reference vascular area, minimal luminal cross-sectional area, plaque cross-sectional area, lesion length, plaque volume and plaque traits were measured by IVUS.

Results

The no-reflow group was observed in 14 cases (11.6%) and normal blood-flow group in 106 cases (89.4%) based on CAG results. There was no statistically significant difference in the patients’ medical history, reference vascular area (no-flow vs. normal-flow; 15.5 ± 3.2 vs. 16.2 ± 3.3, p> 0.05) and lesion length (21.9 ± 5.1 vs. 19.5 ± 4.8, p> 0.05) between the two groups. No-reflow patients had a longer symptom onset to reperfusion time compared to normal blood-flow group [(6.6 ± 3.1) h vs (4.3 ± 2.7) h; p< 0.05] and higher incidence of TIMI flow grade< 3 (71.4% vs 49.0%, p< 0.05). By IVUS examination, the no-reflow group had a significantly increased coronary plaque area and plaque volume compared to normal blood-flow group [(13.7 ± 3.0) mm² vs (10.2 ± 2.9) mm²; (285.4 ± 99.8) mm³ vs (189.7 ± 86.4) mm³; p< 0.01]. The presence of IVUS-detected soft plaque (57.1% vs. 24.0%, p< 0.01), eccentric plaque (64.2% vs. 33.7%, p< 0.05), plaque rupture (50.0% vs. 21.2%, p< 0.01), and thrombosis (42.8% vs. 15.3%) were significantly more common in no-reflow group.

Conclusion

There was no obvious relationship between the coronary risk factors and no-reflow phenomenon. The symptom onset to reperfusion time, TIMI flow grade before stent deployment, plaque area, soft plaques, eccentric plaques, plaque rupture and thrombosis may be risk factors for the no-reflow phenomenon after PCI.