Role of Multimodality Imaging in the Assessment of Myocardial Infarction With Nonobstructive Coronary Arteries: Beyond Conventional Coronary Angiography

The value and accuracy of intracoronary electrocardiogram in the diagnosis of myocardial ischemia in coronary heart disease

BACKGROUND

Although intracoronary electrocardiography (IC-ECG) offers direct electrophysiological insights into myocardial ischemia caused by insufficient coronary blood supply, compared to common diagnostic methods like electrocardiography (ECG), it lacks widespread adoption and robust clinical research.

OBJECTIVE

To analyze the value and accuracy of intracoronary electrocardiogram in myocardial ischemia diagnosis in coronary heart disease patients.

METHODS

Three hundred patients treated at our hospital were included in the study. Patients were categorized into non-ischemic group A (Fraction Flow Reserve [FFR] > 0.8) and ischemic group B (FFR < 0.75) based on FFR examination results. Both groups underwent IC-ECG examination. The ischemic group received percutaneous coronary intervention (PCI) treatment followed by another FFR examination, dividing them into non-ischemic subgroup B1 (FFR > 0.8) and ischemic subgroup B2 (FFR < 0.75). Both subgroups underwent IC-ECG examination. Receiver operating curves were constructed using FFR to assess the clinical utility of different IC-ECG parameters.

RESULTS

Group A patients showed a significant decrease in ST-segment shift at J-point, ST-segment integral, T-peak, T-wave integral, and T-peak to end-time, while the Corrected Q-T interval (QTc-time) was significantly higher in the B group (p< 0.05). The parameters, including ST-segment shift at J-point, ST-segment integral, T-wave integral, T-peak, T-peak to end-time, and QTc-time, were found to have clinical significance in predicting the occurrence of myocardial ischemia (p< 0.05).

CONCLUSION

Intracoronary electrocardiogram QT interval dispersion and Q-T peak (QTp) interval dispersion have a high diagnostic accuracy for myocardial ischemia in coronary heart disease.

Sex Differences and Clinical Outcomes in Patients With Myocardial Infarction With Nonobstructive Coronary Arteries: A Meta-Analysis

BACKGROUND

Although myocardial infarction with nonobstructive coronary arteries (MINOCA) is more common in women, it is unknown whether sex is a risk factor for adverse outcomes in patients with MINOCA. We aimed to investigate the relationship between sex differences and outcomes of patients with MINOCA.

METHODS AND RESULTS

A systematic literature search was performed in PubMed, Embase, and Cochrane databases from their inception until August 2023 for relevant studies. End points were pooled using the Hartung-Knapp-Sidik-Jonkman random-effects model as odds ratio (OR) with 95% CIs. Nine studies, involving 30 281 patients with MINOCA (comprising 18 079 women and 12 202 men), were included in the study. Women were older and had a higher prevalence of hypertension, diabetes, and stroke compared with men. The median duration of follow-up was 3.5 years, with an interquartile range of 2.2 to 4.2 years. Pooled analysis revealed no statistically significant difference in the risk of all-cause mortality (OR, 1.03 [95% CI, 0.87-1.22]), major adverse cardiovascular events (OR, 1.18 [95% CI, 0.89-1.58]), heart failure (OR, 1.32 [95% CI, 0.57-3.03]), stroke (OR, 1.13 [95% CI, 0.56-2.26]), and myocardial infarction (OR, 1.04 [95% CI, 0.29-3.76]) between the 2 groups. Regarding short-term outcomes, women had a significantly higher risk of in-hospital major adverse cardiovascular events compared with men (OR, 1.33 [95% CI, 1.16-1.53]) whereas there was no significant difference in the risk of in-hospital mortality (OR, 0.90 [95% CI, 0.64-1.28]) between the 2 patient groups.

CONCLUSIONS

Despite the differences in demographics and comorbidity profiles, there was no significant difference in the long-term outcomes for patients with MINOCA between sexes. However, it is noteworthy that women experienced a higher risk of in-hospital major adverse cardiovascular events compared with men.

Does the management of patients with myocardial infarction with nonobstructive coronary arteries (MINOCA) changes with advanced diagnostic workup beyond coronary angiography? Results from the "Evaluation of the clinical Profile, Investigations and Cardiac Imaging of the Patients with MINOCA (EPIC-MINOCA Study)"

BACKGROUND

Evaluation of the patients with MINOCA and identifying the underlying aetiology remains challenging. However, investigation in most patients remains limited to coronary angiography (CAG). The study aimed to assess the clinical profile, investigations and cardiac imaging of the patients with MINOCA and its outcomes.

RESULTS

Out of 55 patients with MINOCA, CAG was normal in 16 (29.1%), while 39 (69.9%) had nonobstructive coronary artery disease. Of 55 patients, 34 had limited workup (Group 1) and only 21 had advanced workup (Group 2). In comparison to Group 1, Group 2 had a significantly higher association with the identification of possible underlying aetiology (16 vs. 4, p < 0.001) and a change in the management (10 vs. 3, p = 0.002).

CONCLUSION

Diagnostic workup in patients with MINOCA was limited to CAG in 61.8% of patients in this study. However, patients with advanced workup had a significantly higher association with the change in the treatment and identifying possible underlying aetiology in such patients.

Patient-Specific Numerical Simulations of Coronary Artery Hemodynamics and Biomechanics: A Pathway to Clinical Use

PURPOSE

Numerical models that simulate the behaviors of the coronary arteries have been greatly improved by the addition of fluid-structure interaction (FSI) methods. Although computationally demanding, FSI models account for the movement of the arterial wall and more adequately describe the biomechanical conditions at and within the arterial wall. This offers greater physiological relevance over Computational Fluid Dynamics (CFD) models, which assume the walls do not move or deform. Numerical simulations of patient-specific cases have been greatly bolstered by the use of imaging modalities such as Computed Tomography Angiography (CTA), Magnetic Resonance Imaging (MRI), Optical Coherence Tomography (OCT), and Intravascular Ultrasound (IVUS) to reconstruct accurate 2D and 3D representations of artery geometries. The goal of this study was to conduct a comprehensive review on CFD and FSI models on coronary arteries, and evaluate their translational potential.

METHODS

This paper reviewed recent work on patient-specific numerical simulations of coronary arteries that describe the biomechanical conditions associated with atherosclerosis using CFD and FSI models. Imaging modality for geometry collection and clinical applications were also discussed.

RESULTS

Numerical models using CFD and FSI approaches are commonly used to study biomechanics within the vasculature. At high temporal and spatial resolution (compared to most cardiac imaging modalities), these numerical models can generate large amount of biomechanics data.

CONCLUSIONS

Physiologically relevant FSI models can more accurately describe atherosclerosis pathogenesis, and help to translate biomechanical assessment to clinical evaluation.

[Myocardial Infarction with no obstructive coronary arteries: Imaging plays a central role]

Myocardial infarction with non-obstructive coronary lesion (MINOCA) represents a non-negligible percentage of the proportion of myocardial infarctions (≈6%). Moreover, the long-term prognosis is poor, with an annual mortality rate of 2%. This high mortality rate may be explained by the fact that MINOCA represents a heterogeneous group, and the diagnosis of pathology is poorly understood. It is essential to be aware of this clinical presentation, and to follow the different diagnostic strategies, in order to identify the etiological mechanism, and thus set up a suitable treatment. Many tools are available to support diagnosis, notably in the fields of imaging, the principal contributors being coronary angiography, coronary physiology and pharmacological testing, as well as endo-coronary imaging and cardiac MRI. This review will provide an update on the definition, epidemiology, diagnostic strategies and treatment options for patients with MINOCA.

Spontaneous coronary artery dissection: a focus on post-dissection care for the vascular medicine clinician

Spontaneous coronary artery dissection (SCAD) is an uncommon condition which is increasingly recognized as a cause of significant morbidity. SCAD can cause acute coronary syndrome and myocardial infarction (MI), as well as sudden cardiac death. It presents similarly to atherosclerotic MI although typically in patients with few or no atherosclerotic risk factors, and particularly in women. As more patients are recognized to have this condition, there is a great need for clinician familiarity with diagnostic criteria, as well as with contemporary treatment approaches, and with appropriate patient-centered counseling, including genetic testing, exercise recommendations, and psychological care. The standard of care for patients with SCAD is rapidly evolving. This review therefore summarizes the diagnosis of SCAD, epidemiology, modern treatment, cardiac rehabilitation and preconception counseling, and the current approach to genetic testing, exercise recommendations, and psychological care, all of which are crucial to the vascular medicine specialist.

Imaging patients with myocardial infarction with non-obstructive coronary arteries (MINOCA)

Myocardial infarction with non-obstructive coronary arteries (MINOCA) defines a heterogeneous group of atherosclerotic and non-atherosclerotic conditions, causing myocardial injury in the absence of obstructive coronary artery disease. Unveiling the mechanisms subtended to the acute event is often challenging; a multimodality imaging approach is helpful to aid the diagnosis. Invasive coronary imaging with intravascular ultrasound or optical coherence tomography should be used, when available, during index angiography to detect plaque disruption or spontaneous coronary artery dissection. Cardiovascular magnetic resonance has instead a key role among the non-invasive modalities, allowing the differentiation between MINOCA and its non-ischaemic mimics and providing prognostic information. This educational paper will provide a comprehensive review of the strengths and limitations of each imaging modality in the evaluation of patients with a working diagnosis of MINOCA.

Invasive imaging modalities in a spontaneous coronary artery dissection: when "believing is seeing"

Spontaneous coronary artery dissection (SCAD) is a rare but increasingly recognized cause of acute coronary syndrome (ACS) with recent advancements in cardiac imaging facilitating its identification. However, SCAD is still often misdiagnosed due to the absence of angiographic hallmarks in a significant number of cases, highlighting the importance of meticulous interpretation of angiographic findings and, when necessary, additional usage of intravascular imaging to verify changes in arterial wall integrity and identify specific pathoanatomical features associated with SCAD. Accurate diagnosis of SCAD is crucial, as the optimal management strategies for patients with SCAD differ from those with atherosclerotic coronary disease. Current treatment strategies favor a conservative approach, wherein intervention is reserved for cases with persistent ischemia, patients with high-risk coronary anatomy, or patients with hemodynamic instability. In this paper, we provide a preview of invasive imaging modalities and classical angiographic and intravascular imaging hallmarks that may facilitate proper SCAD diagnosis.

Diagnostic Puzzles and Cause-Targeted Treatment Strategies in Myocardial Infarction with Non-Obstructive Coronary Arteries: An Updated Review

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a distinct subtype of myocardial infarction (MI), occurring in about 8-10% of spontaneous MI cases referred for coronary angiography. Unlike MI with obstructive coronary artery disease, MINOCA's pathogenesis is more intricate and heterogeneous, involving mechanisms such as coronary thromboembolism, coronary vasospasm, microvascular dysfunction, dissection, or plaque rupture. Diagnosing MINOCA presents challenges and includes invasive and non-invasive strategies aiming to differentiate it from alternative diagnoses and confirm the criteria of elevated cardiac biomarkers, non-obstructive coronary arteries, and the absence of alternate explanations for the acute presentation. Tailored management strategies for MINOCA hinge on identifying the underlying cause of the infarction, necessitating systematic diagnostic approaches. Furthermore, determining the optimal post-MINOCA medication regimen remains uncertain. This review aims to comprehensively address the current state of knowledge, encompassing diagnostic and therapeutic approaches, in the context of MINOCA while also highlighting the evolving landscape and future directions for advancing our understanding and management of this intricate myocardial infarction subtype.

MINOCA: Myocardial infarction no obstructive coronary artery disease

Myocardial infarction without obstructive coronary artery disease (MINOCA) is defined as myocardial infarction with mild or no obstructive coronary artery disease (CAD) on angiogram. MINOCA has a number of heterogeneous causes, including coronary disruption, coronary vasospasm, coronary embolism, spontaneous coronary artery dissection (SCAD), and coronary microvascular dysfunction (CMD). Even though MINOCA might have a better prognosis than MI with obstructive CAD, it is not benign. A stepwise diagnostic approach is crucial to identifying the underlying cause of MINOCA or conditions mimicking it. A cause-specific treatment approach is the key to managing MINOCA.

The association of sex-specific hormones with coronary artery plaque characteristics from Miami Heart (MiHeart) study

Objective

The association of sex-specific hormones with coronary computed tomography angiography(CCTA)-based plaque characteristics in women without cardiovascular disease is not well understood. We investigated the association of sex-specific hormones with coronary artery plaque characteristics in a contemporary multiracial cohort with no clinical coronary artery disease (CAD).

Methods

In this cross-sectional analysis, we utilized data from 2,325 individuals with no clinical CAD from the Miami Heart (MiHeart) study. Multivariable logistic regression models were used to investigate the association of sex hormones: sex hormone binding globulin (SHBG), dehydroepiandrosterone (DHEA), free and total testosterone, estradiol, with plaque characteristics among women and men.

Results

Of the 1,155 women, 34.2% had any plaque and 3.4% had any high-risk plaque features (HRP) while among men (n = 1170), 63.1% had any plaque and 10.4% had HRP. Among women, estradiol and SHBG were associated with lower odds of any plaque after adjusting for age and race-ethnicity (estradiol OR per SD increase: 0.87, 95%CI: 0.76-0.98; SHBG OR per SD increase: 0.82, 95%CI: 0.72-0.93) but the significance did not persist after adjustment of cardiovascular risk factors. High free testosterone was associated with higher odds of HRP (aOR:3.48, 95%CI:1.07-11.26) but null associations for the other sex hormones with HRP, in the context of limited sample size. Among men, there were no significant associations between sex-specific hormones and plaque or HRP.

Conclusion

Among young to middle-aged women with no clinical CAD, increasing estradiol and SHBG were associated with lower odds of any plaque and higher free testosterone was associated with HRP. Larger cohorts may be needed to validate this.

Coeliac Disease: A Rare Cause of Myocardial Infarction With Non-Obstructive Coronary Arteries

Myocardial infarction with non-obstructive coronary arteries (MINOCA) poses a diagnostic dilemma. Identifying the underlying etiology is essential to ensuring appropriate management. Cardiac magnetic resonance (CMR) is a valuable tool that can aid clinicians for that purpose. Coeliac disease (CD) is characterized by hypercoagulability and a thrombotic state and represents an exceptional cause of MINOCA. We report the case of a 28-year-old woman who presented with chest pain. The diagnosis of non-ST-elevation MI was obtained based on ECG abnormalities and elevated troponin levels. Coronary angiography was normal. CMR showed late gadolinium enhancement in the lateral left ventricular wall, confirming the diagnosis of MINOCA. A duodenal biopsy allowed the diagnosis of CD. Anticoagulation and a gluten-free diet proved beneficial, with a good outcome after a five-year follow-up. This case highlights the essential role of CMR in MINOCA investigations and the importance of thorough etiological assessment in young patients with no cardiovascular risk factors.

Association between Cardiovascular Risk Factors and High-Risk Features in Myocardial Perfusion Imaging: A Multicenter Study

Background

Myocardial perfusion imaging (MPI) is a noninvasive method with acceptable sensitivity and specificity in diagnosing coronary artery disease (CAD) in moderate-risk patients, including those with CAD risk factors.

Methods

The present cross-sectional, prospective study was conducted on 4886 patients from April 2020 through March 2023 at Chamran and Tehran Heart Center hospitals. A questionnaire regarding anthropometric variables, demographic characteristics, CAD risk factors, and MPI findings was designed.

Results

Totally, 2179 patients (44.6%) had abnormal MPI. Patients with abnormal MPI were significantly older than those with normal MPI. Older age (OR, 1.64; 95% CI, 1.2 to 1.72; P<0.001), diabetes mellitus (DM) (OR, 1.36; 95% CI, 1.1 to 1.48; P=0.012), hypertension (OR, 1.24; 95% CI, 1.04 to 1.37; P=0.032), and dyslipidemia (OR, 1.54; 95% CI, 1.25 to 1.8; P<0.001) were associated with abnormal MPI independently. Patients with more CAD risk factors were more likely to have abnormal MPI. Thus, in patients without or at most with 1 risk factor and those with 8 CAD risk factors, the likelihood of abnormal MPI was 3.7% and 76.2%, respectively. The frequency of left ventricular dilation and right ventricular prominence was significantly higher in patients with older age (P<0.001 and P=0.043, respectively), dyslipidemia (P<0.001 and P=0.007, respectively), DM (P<0.001 and P<0.001, respectively), and hypertension (P=0.048 and P=0.057, respectively).

Conclusion

Individuals with CAD risk factors, especially those with older age, DM, hypertension, or dyslipidemia, require meticulous attention during CAD evaluation, particularly via MPI.

Myocardial infarction with non-obstructive coronary arteries: Etiology, diagnosis, treatment and prognosis

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is responsible for 10% of myocardial infarctions. Previously, patients were thought to have good prognosis, but evidence-based management and treatment strategies were scarce. Today, researchers and physicians recognize MINOCA as a condition with non-trivial mortality and morbidity. Therapeutic strategies are highly dependent on the underlying disease mechanism in each patient. However, to reach a diagnosis of MINOCA, a multimodal approach is required and, even with an optimal work-up, the cause remains unknown in 8-25% of patients. Research has been growing and position papers from the European Society of Cardiology (ESC) and the American Heart Association/American College of Cardiology have been published, and MINOCA has been included in the more recent ESC guidelines on myocardial infarction. Nonetheless, some clinicians still assume that the absence of coronary obstruction excludes the possibility of acute myocardial infarction. Therefore, in the present paper, we aim to compile and present the available data on the etiology, diagnosis, treatment, and prognosis of MINOCA.

Myocardial infarction with non-obstructive coronary arteries (MINOCA)

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is evident in up to 15% of all acute myocardial infarctions (AMI) and disproportionally affects females. Despite younger age, female predominance, and fewer cardiovascular risk factors, MINOCA patients have a worse prognosis than patients without cardiovascular disease and a similar prognosis compared to patients with MI and obstructive coronary artery disease (CAD). MINOCA is a syndrome with a broad differential diagnosis that includes both ischemic [coronary artery plaque disruption, coronary vasospasm, coronary microvascular dysfunction, spontaneous coronary artery dissection (SCAD), and coronary embolism/thrombosis] and non-ischemic mechanisms (Takotsubo cardiomyopathy, myocarditis, and non-ischemic cardiomyopathy)-the latter called MINOCA mimickers. Therefore, a standardized approach that includes multimodality imaging, such as coronary intravascular imaging, cardiac magnetic resonance, and in selected cases, coronary reactivity testing, including provocation testing for coronary vasospasm, is necessary to determine underlying etiology and direct treatment. Herein, we review the prevalence, characteristics, prognosis, diagnosis, and treatment of MINOCA -a syndrome often overlooked.

Multimodality Imaging in the Detection of Ischemic Heart Disease in Women

Women with coronary artery disease tend to have a worse short and long-term prognosis relative to men and the incidence of atherosclerotic cardiovascular disease is increasing. Women are less likely to present with classic anginal symptoms when compared with men and more likely to be misdiagnosed. Several non-invasive imaging modalities are available for diagnosing ischemic heart disease in women and many of these modalities can also assist with prognostication and help to guide management. Selection of the optimal imaging modality to evaluate women with possible ischemic heart disease is a scenario which clinicians often encounter. Earlier modalities such as exercise treadmill testing demonstrate significant performance variation in men and women, while newer modalities such as coronary CT angiography, myocardial perfusion imaging and cardiac magnetic resonance imaging are highly specific and sensitive for the detection of ischemia and coronary artery disease with greater parity between sexes. Individual factors, availability, diagnostic performance, and female-specific considerations such as pregnancy status may influence the decision to select one modality over another. Emerging techniques such as strain rate imaging, CT-myocardial perfusion imaging and cardiac magnetic resonance imaging present additional options for diagnosing ischemia and coronary microvascular dysfunction.

Multimodality Imaging of Sudden Cardiac Death and Acute Complications in Acute Coronary Syndrome

Sudden cardiac death (SCD) is a potentially fatal event usually caused by a cardiac arrhythmia, which is often the result of coronary artery disease (CAD). Up to 80% of patients suffering from SCD have concomitant CAD. Arrhythmic complications may occur in patients with acute coronary syndrome (ACS) before admission, during revascularization procedures, and in hospital intensive care monitoring. In addition, about 20% of patients who survive cardiac arrest develop a transmural myocardial infarction (MI). Prevention of ACS can be evaluated in selected patients using cardiac computed tomography angiography (CCTA), while diagnosis can be depicted using electrocardiography (ECG), and complications can be evaluated with cardiac magnetic resonance (CMR) and echocardiography. CCTA can evaluate plaque, burden of disease, stenosis, and adverse plaque characteristics, in patients with chest pain. ECG and echocardiography are the first-line tests for ACS and are affordable and useful for diagnosis. CMR can evaluate function and the presence of complications after ACS, such as development of ventricular thrombus and presence of myocardial tissue characterization abnormalities that can be the substrate of ventricular arrhythmias.

MINOCA: One Size Fits All? Probably Not—A Review of Etiology, Investigation, and Treatment

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a heterogeneous group of conditions that include both atherosclerotic (coronary plaque disruption) and non-atherosclerotic (spontaneous coronary artery dissection, coronary artery spasm, coronary artery embolism, coronary microvascular dysfunction, and supply–demand mismatch) causes resulting in myocardial damage that is not due to obstructive coronary artery disease. Failure to identify the underlying cause may result in inadequate and inappropriate therapy in these patients. The cornerstone of managing MINOCA patients is to identify the underlying mechanism to achieve the target treatment. Intravascular imaging is able to identify different morphologic features of coronary plaques, while cardiac magnetic resonance is the gold standard for detection of myocardial infarction in the setting of MINOCA. In this review, we summarize the relevant clinical issues, contemporary diagnosis, and treatment options of MINOCA.