Diagnostic value of Cardiac Magnetic Resonance Imaging and Intracoronary Optical Coherence Tomography in patients with a working diagnosis of Myocardial Infarction with Non-obstructive Coronary Arteries - A Systematic review and Meta-analysis

How to Use Cardiac Magnetic Resonance Imaging in Myocardial Infarction With Nonobstructive Coronary Arteries

The working diagnosis Myocardial Infarction with Nonobstructive Coronary Arteries (MINOCA) is being increasingly recognized with the common use of high-sensitivity troponins and coronary angiography, accounting for 5% to 10% of all acute myocardial infarction presentations. Cardiac magnetic resonance (CMR) imaging is pivotal in patients presenting with suspected MINOCA, mainly to delineate those with a nonischemic cause, for example, myocarditis and Takotsubo syndrome, from those with true ischemic myocardial infarction, that is, MINOCA. The optimal timing for CMR imaging in patients with suspected MINOCA has been uncertain and, until recently, not been examined prospectively. Previous retrospective studies have indicated that the diagnostic yield decreases with time from the acute event. The SMINC studies (Stockholm Myocardial Infarction with Normal Coronaries) show that CMR should be performed early in all patients with the working diagnosis of MINOCA, with the possible exception of patients who are clearly identified as having Takotsubo syndrome as determined by echocardiography. In addition to CMR imaging, other investigations of importance in selected patients may be pulmonary artery computed tomography to exclude pulmonary embolism, optical coherence tomography to identify plaque disruption, and acetylcholine provocation to identify coronary artery spasm. Imaging of patients with the working diagnosis MINOCA, which is centered on CMR together with supplemental investigations, results in a clear diagnosis in approximately three-quarters of the patients. This is a good example of personalized medicine, because a correct diagnosis will not only increase the satisfaction of the individual patient but also result in optimizing treatment without harming the patient.

Systematic review of cardiovascular magnetic resonance imaging T1 and T2 mapping in patients with Takotsubo syndrome

Background

Current imaging advancements quantify the use of cardiovascular magnetic resonance (CMR) derived T1 and T2 tissue characterization as robust indicators for cardiomyopathies, but limited literature exists on its clinical application in Takotsubo syndrome (TTS). This systematic review evaluated the T1 and T2 parametric mapping to delineate the current diagnostic and prognostic CMR imaging outcomes in TTS.

Methods

A comprehensive literature search until October 2023 was performed on ScienceDirect, PubMed, Web of Science, and Cochrane Library by two independent reviewers adhering to the PRISMA framework. The Newcastle-Ottawa Scale (NOS) was used to evaluate the methodological quality of studies.

Results

Out of 198 results, 8 studies were included in this qualitative synthesis, accounting for a total population of 399 subjects (TTS = 201, controls = 175, acute myocarditis = 14, and acute regional myocardial oedema without infarction = 9). Approximately 50.4 % were TTS patients aged between 61 and 73 years, whereof, females (n = 181, 90.0 %) and apical variants (n = 180, 89.6 %) were significantly higher, and emotional stressor (n = 42; 20.9 %) was more prevalent than physical (n = 27; 13.4 %). The NOS identified 62.5 % of studies as moderate and 37.5 % as high quality. Parametric tissue mapping revealed significantly prolonged T1 and T2 relaxation times at 1.5T and 3T respectively in TTS (1053-1164 msec, 1292-1438 msec; and 56-67 msec, 60-90 msec) with higher extracellular volume (ECV) fraction (29-36 %), compared to healthy subjects (944-1211 msec, 1189-1251 msec; and 46-54 msec, 32-68 msec; 23-29 %) and myocarditis (1058 msec, 60 msec). Other significant myocardial abnormalities included increased left ventricular (LV) end-systolic and diastolic volume and reduced global longitudinal strain. Overall, myocardial oedema, altered LV mass and strain, and worse LV systolic function, with higher native T1, T2, and ECV values were consistent.

Conclusions

Future research with substantially larger clinical trials is vital to explore the CMR imaging findings in diverse TTS patient cohorts and correlate the T1 and T2 mapping outcomes with demographic/clinical covariates. CMR is a valuable imaging tool for TTS diagnosis and prognostication. T1 and T2 parametric mapping facilitates the quantification of oedema, inflammation, and myocardial injury in Takotsubo.

Pathophysiology of Myocardial Infarction With Nonobstructive Coronary Artery Disease: A Contemporary Systematic Review

Background

Myocardial infarction with nonobstructive coronary artery disease (MINOCA) is defined as acute myocardial infarction (AMI) with angiographically nonobstructive coronary artery disease. MINOCA represents 6% of all AMI cases and is associated with increased mortality and morbidity. However, the wide array of pathophysiological factors and causes associated with MINOCA presents a diagnostic conundrum. Therefore, we conducted a contemporary systematic review of the pathophysiology of MINOCA.

Methods

A comprehensive systematic review of MINOCA was carried out through the utilization of the PubMed database. All systematic reviews, meta-analyses, randomized controlled trials, and cohort studies available in English or French that reported on the pathophysiology of MINOCA published after January 1, 2013 were retained.

Results

Of the 600 identified records, 80 records were retained. Central to the concept of MINOCA is the definition of AMI, characterized by the presence of myocardial damage reflected by elevated cardiac biomarkers in the setting of acute myocardial ischemia. As a result, a structured approach should be adopted to thoroughly assess and address clinically overlooked obstructive coronary artery disease, and cardiac and extracardiac mechanisms of myocyte injury. Once these options have been ruled out, a diagnosis of MINOCA can be established, and the appropriate multimodal assessment can be conducted to determine its specific underlying cause (plaque disruption, epicardial coronary vasospasm, coronary microvascular dysfunction, and coronary embolism and/or spontaneous coronary dissection or supply-demand mismatch).

Conclusions

Integrating a suitable definition of AMI and understanding the pathophysiological mechanisms of MINOCA are crucial to ensure an effective multimodal diagnostic evaluation and the provision of adequate tailored therapies.

Intracoronary Imaging Versus Coronary Angiography Guidance for Implantation of Second and Third Generation Drug Eluting Stents in a Systematic Review and Meta-Analysis of Randomized Controlled Trials

Intracoronary imaging (ICI) facilitates stent implant by characterizing the lesion calcification, providing accurate vessel dimensions, and optimizing the stent results. We sought to investigate the outcomes of routine ICI versus coronary angiography (CA) to guide percutaneous coronary intervention (PCI) with second- and third-generation drug-eluting stents. A systematic search of PubMed, Medline, and Cochrane databases was conducted from their inception to July 16, 2022 for randomized controlled trials comparing routine ICI with CA. The primary outcome was major adverse cardiovascular events. The secondary outcomes of interest were target lesion revascularization, target vessel revascularization, myocardial infarction, stent thrombosis, and cardiac and all-cause mortality. A random-effects model was used to calculate the pooled incidence and relative risk (RR) with 95% confidence intervals (CIs). A total of 9 randomized controlled trials with 5,879 patients (2,870 ICI-guided and 3,009 CA-guided PCI) met the inclusion criteria. The ICI and CA groups were similar in demographic characteristics and co-morbidity profiles. Compared with CA, patients in the routine ICI-guided PCI group had lower rates of major adverse cardiovascular events (RR 0.61, 95% CI 0.48 to 0.78, p <0.0001), target lesion revascularization (RR 0.60, 95% CI 0.43 to 0.83, p = 0.002), target vessel revascularization (RR 0.72, 95% CI 0.51 to 1.00, p = 0.05), and myocardial infarction (RR 0.48, 95% CI 0.25 to 0.95, p = 0.03). There were no significant differences in stent thrombosis or cardiac/all-cause mortality between the 2 strategies. In conclusion, routine ICI-guided PCI strategy, compared with CA guidance alone, is associated with improved clinical outcomes, largely driven by lower repeat revascularization.

Infective Endocarditis Risk with Melody versus Sapien Valves Following Transcatheter Pulmonary Valve Implantation: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

BACKGROUND

Transcatheter pulmonary valve implantation (TPVI) is an effective non-surgical treatment method for patients with right ventricle outflow tract dysfunction. The Medtronic Melody and the Edwards Sapien are the two valves approved for use in TPVI. Since TPVI patients are typically younger, even a modest annual incidence of infective endocarditis (IE) is significant. Several previous studies have shown a growing risk of IE after TPVI. There is uncertainty regarding the overall incidence of IE and differences in the risk of IE between the valves.

METHODS

A systematic search was conducted in the MEDLINE, EMBASE, PubMed, and Cochrane databases from inception to 1 January 2023 using the search terms 'pulmonary valve implantation', 'TPVI', or 'PPVI'. The primary outcome was the pooled incidence of IE following TPVI in Melody and Sapien valves and the difference in incidence between Sapien and Melody valves. Fixed effect and random effect models were used depending on the valve. Meta-regression with random effects was conducted to test the difference in the incidence of IE between the two valves.

RESULTS

A total of 22 studies (including 10 Melody valve studies, 8 Sapien valve studies, and 4 studies that included both valves (572 patients that used the Sapien valve and 1395 patients that used the Melody valve)) were used for the final analysis. Zero IE incidence following TPVI was reported by eight studies (66.7%) that utilized Sapien valves compared to two studies (14.3%) that utilized Melody valves. The pooled incidence of IE following TPVI with Sapien valves was 2.1% (95% CI: 0.9% to 5.13%) compared to 8.5% (95% CI: 4.8% to 15.2%) following TPVI with Melody valves. Results of meta-regression indicated that the Sapien valve had a 79.6% (95% CI: 24.2% to 94.4%, p = 0.019; R2 = 34.4) lower risk of IE incidence compared to the Melody valve.

CONCLUSIONS

The risk of IE following TPVI differs significantly. A prudent valve choice in favor of Sapien valves to lower the risk of post-TPVI endocarditis may be beneficial.

Contemporary Diagnosis and Management of Patients with MINOCA

PURPOSE OF REVIEW

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is defined as acute myocardial infarction (MI) with angiographically no obstructive coronary artery disease or stenosis ≤ 50%. MINOCA is diagnostically challenging and complex, making it difficult to manage effectively. This condition accounts for 6-8% of all MI and poses an increased risk of morbidity and mortality after diagnosis. Prompt recognition and targeted management are essential to improve outcomes and our understanding of this condition, but this process is not yet standardized. This article offers a comprehensive review of MINOCA, delving deep into its unique clinical profile, invasive and noninvasive diagnostic strategies for evaluating MINOCA in light of the lack of widespread availability for comprehensive testing, and current evidence surrounding targeted therapies for patients with MINOCA.

RECENT FINDINGS

MINOCA is not uncommon and requires comprehensive assessment using various imaging modalities to evaluate it further. MINOCA is a heterogenous working diagnosis that requires thoughtful approach to diagnose the underlying disease responsible for MINOCA further.

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.

Role of Endomyocardial Biopsy in Diagnostics of Myocarditis

Endomyocardial biopsy as the cornerstone of diagnostics has been re-evaluated throughout the years, leaving unanswered questions on the precedence of it. The reported incidence of myocarditis has increased during the pandemic of coronavirus disease 2019 (COVID-19), reinforcing discussions on appropriate diagnostics of myocarditis. By analysis of evidence-based literature published within the last demi-decade, we aimed to summarize the most recent information in order to evaluate the current role of endomyocardial biopsy in diagnostics and management of myocarditis. For the most part, research published over the last five years showed ongoing uncertainty regarding the use, informativeness, safety and necessity of performing a biopsy. Special circumstances, such as fulminant clinical course or failure to respond to empirical treatment, were reconfirmed as justified indications, with a growing applicability of non-invasive diagnostic approaches for most other cases. We concluded that endomyocardial biopsy, if performed properly and with adjunct diagnostic methods, holds a critical role for treatment correction in specific histological subtypes of myocarditis and for differential diagnosis between immune-mediated myocarditis and secondary infections due to immunosuppressive treatment. A high level of possible misdiagnosing was detected, indicating the need to review terminology used to describe findings of myocardial inflammation that did not meet Dallas criteria.

Coronary functional assessment in non-obstructive coronary artery disease: Present situation and future direction

Non-obstructive coronary artery disease (CAD), which is defined as coronary stenosis <50%, has been increasingly recognized as an emerging entity in clinical practice. Vasomotion abnormality and coronary microvascular dysfunction are two major mechanisms contributing to the occur of angina with non-obstructive CAD. Although routine coronary functional assessment is limited due to several disadvantages, functional evaluation can help to understand the pathophysiological mechanism and/or to exclude specific etiologies. In this review, we summarized the potential mechanisms involved in ischemia with non-obstructive coronary arteries (INOCA) and myocardial infarction with non-obstructive coronary arteries (MINOCA), the two major form of non-obstructive CAD. Additionally, we reviewed currently available functional assessment indices and their use in non-obstructive CAD. Furthermore, we speculated that novel technique combined anatomic and physiologic parameters might provide more individualized therapeutic choice for patients with non-obstructive CAD.