Myocardial infarction with angiographically normal coronary arteries

Clinical presentation and management of myocardial infarction with nonobstructive coronary arteries (MINOCA): A literature review

Myocardial Infarction with Nonobstructive Coronary Arteries (MINOCA), as the name implies, is an acute myocardial infarction (MI) in the absence of significant coronary artery obstruction. Diagnosis and management of such cases have been challenging. There are many etiologies of MINOCA including coronary artery spasm, coronary microvascular dysfunction, plaque disruption, spontaneous coronary thrombosis or emboli, spontaneous coronary artery dissection, or cardiomyopathies. In this paper, the pathophysiology, diagnostic work-up, and clinical management for each subtype are described, and an overarching approach on how to evaluate and manage a patient presenting with MINOCA.

Role of cardiovascular magnetic resonance in the prognosis of patients with myocardial infarction with non-obstructive coronary arteries

BACKGROUND

It is estimated that 5% to 10% of patients with myocardial infarction (MI) present with no obstructive coronary artery lesions. Until now, most studies have focused on acute coronary syndrome, including different clinical entities with a similar presentation encompassed under the term MINOCA (MI with non-obstructive coronary arteries). The aim of this study is to assess the prognosis of patients diagnosed with true infarction, confirmed by cardiovascular magnetic resonance (CMR), in the absence of significant coronary lesions.

METHODS

Prospective multicenter registry study, including 120 consecutive patients with a CMR-confirmed MI without obstructive coronary artery lesions. The primary clinical outcome was major adverse cardiovascular events (MACE: death, non-fatal infarction, stroke, or cardiac readmission), assessed over three years.

RESULTS

Seventy-six patients (63.3%) were admitted with a diagnosis of acute coronary syndrome, and 44 (36.6%) for other causes (mainly heart failure); the definitive diagnosis was established by CMR. Most patients (64.2%) were men, and the mean age was 58.8 ± 13.5 years. Patients presented with small infarcts: 83 (69.1%) showed late gadolinium enhancement (LGE) in one or two myocardial segments, mainly transmural (in 77.5% of patients) and with a preserved left ventricular ejection fraction (median 54.8%, interquartile range 37-62). The most frequent infarct location was inferolateral (n = 38, 31.7%). During follow-up, 43 patients (35.8%) experienced a MACE, including 9 (7.5%) who died. In multivariable analysis, LGE in two versus one myocardial segment doubled the risk of adverse cardiac events (hazard ratio [HR] 2.32, 95% confidence interval [CI] 0.97-5.83, p = 0.058). Involvement of three or more myocardial segments almost tripled the risk (HR 2.71, 95% CI 1.04-7.04, p = 0.040 respectively).

CONCLUSIONS

Patients with true MI but without significant coronary artery lesions predominantly had small infarcts. Myocardial 3-segment LGE involvement is associated with a significantly higher risk of adverse cardiac events.

Acute myocardial infarction not attributed to coronary artery disease: A seldom initial presentation of a left ventricular myxoma

Although myxoma represents the most frequent non-malignant cardiac primary tumor; it is extremely rare met in the left ventricle. Clinical features of the neoplasm extend from symptomless to critical signs of either ischemia or embolism. We describe here an unusual case of a huge left ventricular myxoma in a 68-year-old man, presented with clinical and ECG findings of an inferior wall myocardial infarction. The patient was primarily referred to our institution for coronary angiography, which showed no coronary artery disease. Further examinations revealed a left ventricular mass as the possible source of embolization, thus the patient underwent surgery for tumor excision. The postoperative course was unremarkable. A bibliographical analysis demonstrated that those tumors are rare but treatable causes of embolic myocardial infarction, thus profound clinical intuition, proper utilization of imaging modalities, administration of anticoagulants preoperatively, as well immediate surgical removal are justified.

Myocardial Infarction With Nonobstructive Coronary Arteries (MINOCA): Potential Etiologies, Mimics and Imaging Findings

Myocardial infarction with nonobstructive coronary arteries (MINOCA) occurs when a patient presents with positive cardiac enzymes in the absence of obstructive atherosclerosis on coronary angiography. Several hypotheses for the pathogenesis of MINOCA have been suggested and multiple potential underlying etiologies have been reported. This review will outline the reported causes of MINOCA and associated major imaging features. In doing so, it will increase awareness of this entity and equip cardiac imagers with the knowledge to appropriately tailor imaging to make a prompt and accurate diagnosis.

Contemporary Diagnosis and Management of Patients With Myocardial Infarction in the Absence of Obstructive Coronary Artery Disease: A Scientific Statement From the American Heart Association

Myocardial infarction in the absence of obstructive coronary artery disease is found in ≈5% to 6% of all patients with acute infarction who are referred for coronary angiography. There are a variety of causes that can result in this clinical condition. As such, it is important that patients are appropriately diagnosed and an evaluation to uncover the correct cause is performed so that, when possible, specific therapies to treat the underlying cause can be prescribed. This statement provides a formal and updated definition for the broadly labelled term MINOCA (incorporating the definition of acute myocardial infarction from the newly released “Fourth Universal Definition of Myocardial Infarction”) and provides a clinically useful framework and algorithms for the diagnostic evaluation and management of patients with myocardial infarction in the absence of obstructive coronary artery disease.

Medical Therapy for Secondary Prevention and Long-Term Outcome in Patients With Myocardial Infarction With Nonobstructive Coronary Artery Disease

BACKGROUND

Myocardial infarction with nonobstructive coronary arteries (MINOCA) occurs in 5% to 10% of all patients with myocardial infarction. Clinical trials of secondary prevention treatment in MINOCA patients are lacking. Therefore, the aim of this study was to examine the associations between treatment with statins, renin-angiotensin system blockers, β-blockers, dual antiplatelet therapy, and long-term cardiovascular events.

METHODS

This is an observational study of MINOCA patients recorded in the SWEDEHEART registry (the Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapy) between July 2003 and June 2013 and followed until December 2013 for outcome events in the Swedish Cause of Death Register and National Patient Register. Of 199 162 myocardial infarction admissions, 9466 consecutive unique patients with MINOCA were identified. Among those, the 9136 patients surviving the first 30 days after discharge constituted the study population. Mean age was 65.3 years, and 61% were women. No patient was lost to follow-up. A stratified propensity score analysis was performed to match treated and untreated groups. The association between treatment and outcome was estimated by comparing between treated and untreated groups by using Cox proportional hazards models. The exposures were treatment at discharge with statins, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, and dual antiplatelet therapy. The primary end point was major adverse cardiac events defined as all-cause mortality, hospitalization for myocardial infarction, ischemic stroke, and heart failure.

RESULTS

At discharge, 84.5%, 64.1%, 83.4%, and 66.4% of the patients were on statins, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, and dual antiplatelet therapy, respectively. During the follow-up of a mean of 4.1 years, 2183 (23.9%) patients experienced a major adverse cardiac event. The hazard ratios (95% confidence intervals) for major adverse cardiac events were 0.77 (0.68-0.87), 0.82 (0.73-0.93), and 0.86 (0.74-1.01) in patients on statins, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and β-blockers, respectively. For patients on dual antiplatelet therapy followed for 1 year, the hazard ratio was 0.90 (0.74-1.08).

CONCLUSIONS

The results indicate long-term beneficial effects of treatment with statins and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers on outcome in patients with MINOCA, a trend toward a positive effect of β-blocker treatment, and a neutral effect of dual antiplatelet therapy. Properly powered randomized clinical trials to confirm these results are warranted.

Newer perspectives of coronary artery disease in young

Coronary artery disease (CAD) occurring in less than 45 years of age is termed as young CAD. Recent studies show a prevalence of 1.2% of CAD cases in this age group. Ethnic wise south Asians especially Indians are more vulnerable to have CAD in young age group with a prevalence of 5% to 10%. Conventional risk factors such as smoking, diabetes, hypertension, obesity and family history seems to be as important as in older CAD subjects. But the prevalence of these risk factors seems to vary in younger subjects. By far the most commonly associated risk factor is smoking in young CAD. Several genes associated with lipoprotein metabolism are now found to be associated with young CAD like cholesterol ester transfer protein (CETP) gene, hepatic lipase gene, lipoprotein lipase gene, apo A1 gene, apo E gene and apo B. Biomarkers such as lipoprotein (a), fibrinogen, D-dimer, serum Wnt, gamma glutamyl transferase, vitamin D2 and osteocalcin are seems to be associated with premature CAD in some newer studies. In general CAD in young has better prognosis than older subjects. In terms of prognosis two risk factors obesity and current smoking are associated with poorer outcomes. Angiographic studies shows predominance of single vessel disease in young CAD patients. Like CAD in older person primary and secondary prevention plays an important role in prevention of new and further coronary events.

Usefulness of late gadolinium enhancement MRI combined with stress imaging in predictive significant coronary stenosis in new-diagnosed left ventricular dysfunction

BACKGROUND

To evaluate the accuracy of late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) and imaging stress test in predicting significant coronary artery disease (CAD) in left ventricular (LV) dysfunction.

METHODS

We enrolled 187 consecutive out-patients (61±17years) with new evidence of depressed (<45%) ejection fraction and no history of previous heart diseases and absence of Q-waves. All patients underwent coronary angiography (CA) and to LGE-CMR examination to identify ischemic and non-ischemic LGE. All patients underwent stress imaging to determine the presence of myocardial ischemia.

RESULTS

Ischemic-LGE was found in 83 patients and non-ischemic-LGE in 104. Significant CAD on CA was found in 86/187 patients. Ischemic-LGE showed a specificity of 94%, a sensitivity of 89% and an accuracy of 92% in identifying significant CAD. Imaging stress test was negative in 98/105 patients without CAD, and positive in 42/82 with significant CAD, showing a specificity of 93%, a sensitivity of 51% and an accuracy of 75% in identifying CAD. Combining CMR and stress test imaging, 94 patients had ischemic-LGE pattern and/or positive stress test for ischemia; of these 81/94 had significant CAD on CA and 13 had no CAD. Among the 93 patients with both tests negative, significant CAD was found in 5/93 patients. The combination of LGE and stress respect to only LGE did not improve the diagnostic accuracy (90 vs 92% respectively).

CONCLUSION

LGE-CMR had high accuracy in predicting significant CAD in ischemic LV dysfunction or as a bystander in non ischemic dysfunction.

Ankle brachial index most important to identify polyvascular disease in patients with non-ST elevation or ST-elevation myocardial infarction

BACKGROUND

Atherosclerosis is a systemic disease. In patients with acute myocardial infarction (MI) the extent of polyvascular disease (PvD) is largely unknown. In this study we investigate the prevalence and clinical characteristics predictive of PvD in patients with non-ST-elevation (NSTEMI) and ST-elevation (STEMI) MI.

METHOD

375 patients with acute MI included in the REBUS (Relevance of Biomarkers for Future Risk of Thromboembolic Events in Unselected Post-myocardial Infarction Patients) study were examined. Atherosclerotic changes were assessed in three arterial beds by coronary angiography, carotid ultrasound and ankle brachial index (ABI). Results compared findings of atherosclerosis in three arterial beds to fewer than 3 beds. PvD was defined as atherosclerosis in all three arterial beds.

RESULTS

A medical history of MI, peripheral artery disease (PAD) or stroke was reported at admission in 17.9%, 2.1% and 3.7% of the patients, respectively. After evaluation, abnormal ABI was found in 20.3% and carotid artery atherosclerosis in 54.9% of the patients. In the total population, PvD was found in 13.8% of patients with no significant differences observed between NSTEMI and STEMI patients. Age (p<0.001), diabetes (p=0.039), previous PAD (p=0.009) and female gender (p=0.016) were associated with PvD. ABI was the most important predictor of PvD with a positive predictive value of 68.4% (95% CI 57.7-79.2%) and specificity of 92.4% (95% CI 89.5-95.4%).

CONCLUSIONS

PvD is underdiagnosed in patients suffering from MI, both NSTEMI and STEMI. ABI is a useful and simple measurement that appears predictive of widespread atherosclerosis in these patients.

The Role of Cardiac MRI in Patients with Troponin-Positive Chest Pain and Unobstructed Coronary Arteries

Acute coronary syndrome (ACS) still remains one of the leading causes of mortality and morbidity worldwide. Seven to fifteen percent of patients presenting with ACS have unobstructed coronary artery disease (CAD) on urgent angiography. Patients with ACS and unobstructed coronary arteries represent a clinical dilemma and their diagnosis and management is quite variable in current practice. Cardiovascular magnetic resonance imaging with its unique non-invasive myocardial tissue characterization property has the potential to identify underlying etiologies and reach a final diagnosis. These include acute and chronic myocarditis, embolic/spontaneous recanalization myocardial infarction, and Tako-Tsubo cardiomyopathy, and other conditions. Establishing a final diagnosis has a direct implication on patient's management and prognosis. In this article, we have reviewed the current evidence on the diagnostic role of cardiac magnetic resonance (CMR) in patients with ACS and unobstructed coronary arteries. We have also highlighted the potential role of CMR as a risk stratification or prognostication tool for this patient population.

Effect of Gender on Patients With ST-Elevation and Non-ST-Elevation Myocardial Infarction Without Obstructive Coronary Artery Disease

The aim of this study was to compare the prognoses of patients with ST-segment elevation myocardial infarction (STEMI) and those with non-ST-segment elevation myocardial infarction (NSTEMI) without obstructive coronary artery disease (CAD) and the risk associated with gender for future cardiovascular events. The study population was selected from 95,849 patients who underwent coronary angiography for myocardial infarction from 2005 to 2010 and registered in the Swedish Coronary Angiography and Angioplasty Registry (SCAAR). Outcome analyses, including all-cause death, myocardial infarction, congestive heart failure, stroke, and revascularization, were performed in 2,268 patients with STEMI and 10,904 with NSTEMI without obstructive CAD (<50% stenosis). Hazard ratios and 95% confidence intervals comparing women with men were calculated for events, adjusting for cardiovascular risk factors and age. Nonobstructive CAD was found in 7% of patients with STEMI (6% men, 10% women) and in 17% of those with NSTEMI (11% men, 28% women). During a median follow-up of 2.6 years, 8% of patients with STEMI and 5% of those with NSTEMI died. Gender-associated differences in risk were observed in patients with NSTEMI, with adjusted hazard ratios lower in women than men for mortality (hazard ratio 0.90, 95% confidence interval 0.50 to 0.73) and congestive heart failure (hazard ratio 0.61, 95% confidence interval 0.52 to 0.72). In the 2 groups, women underwent less revascularization. In conclusion, nonobstructive CAD was more common in patients with NSTEMI than those with STEMI, as well as in women compared with men. Long-term mortality in patients with nonobstructive CAD was higher after STEMI than NSTEMI. The gender differences in outcomes suggest gender differences in the underlying pathogenesis of myocardial infarction without obstructive CAD.

Myocarditis or "true" infarction by cardiac magnetic resonance in patients with a clinical diagnosis of myocardial infarction without obstructive coronary disease: A meta-analysis of individual patient data

OBJECTIVE

Myocardial Infarction with Non-Obstructed Coronary Arteries (MINOCA) is common, but the causes are to a large extent unknown. Thus, we aimed to study the prevalence of myocarditis and "true" myocardial infarction determined by cardiac magnetic resonance (CMR) imaging in MINOCA patients, and risk markers for these two conditions in this population.

METHODS

A search was made in the PubMed and Cochrane databases using the search terms "Myocardial infarction", "Coronary angiography", "Normal coronary arteries" and "MRI". All relevant abstracts were read and seven of the studies fulfilled the inclusion criteria; studies describing case series of patients fulfilling the diagnosis of acute myocardial infarction with normal or non-obstructive coronary arteries on coronary angiography that were investigated with CMR imaging. Data from five of these studies are presented.

RESULTS

A total of 556 patients from 5 different sites were included. Fifty-one percent were men with a mean age of 52 ± 16 years. Thirty-three per cent of the patients had myocarditis (n = 183), whereas 21% of the patients had infarction on CMR (n = 115). Young age and a high CRP were associated with myocarditis whereas male sex, treated hyperlipidemia, high troponin ratio and low CRP were associated with "true" myocardial infarction.

CONCLUSION AND RELEVANCE

The results of this meta-analysis of individual data showed that myocarditis and "true" myocardial infarction are common in MINOCA when determined by CMR imaging. This information emphasizes the importance of performing CMR imaging in MINOCA patients and can be used clinically to guide diagnostics and treatment of MINOCA patients.

Acute Spontaneous Coronary Artery Thrombosis as Initial Presentation of HIV Infection in a Young Man

Introduction. The presentation of acute coronary syndrome (ACS) in young HIV patients may be atypical with different pathophysiological and clinical features. Acute coronary thrombosis, as a presentation of acute coronary syndrome in young patients with HIV, raises diagnostic and treatment challenges. Case Presentation. We describe a case of a 33-year-old African man, without traditional atherosclerotic risk factors, who presented with chest pain of acute onset. Emergent coronary angiography revealed extensive thrombus in the left anterior descending coronary artery with no evidence of atherosclerosis in this or other coronary vessels. Plaque and/or thrombus prolapse through the stent was noted following percutaneous coronary intervention (PCI). Resolution of chest pain and improvement in ST-segment elevation was noted after the procedure. A diagnosis of HIV infection was made during the workup for HIV infection. Conclusion. In young patients without traditional risk factors, HIV infection is a possible etiological factor for spontaneous coronary artery thrombosis. Percutaneous coronary intervention in patients with this presentation may be compounded with atherothrombotic complications. The likely pathophysiological pathway is superficial endothelial cell denudation as a result of chronic inflammation and immune activation.

Diagnostic contribution of cardiac magnetic resonance in patients with acute coronary syndrome and culprit-free angiograms

BACKGROUND

In spite of robust knowledge about underlying ischemic myocardial damage, acute coronary syndromes (ACS) with culprit-free angiograms raise diagnostic concerns. The present study aimed to evaluate the additional value of cardiac magnetic resonance (CMR) over commonly available non-CMR standard tests, for the differentiation of myocardial injury in patients with ACS and non-obstructed coronary arteries.

MATERIAL/METHODS

Patients with ACS, elevated hs-TnT, and a culprit-free angiogram were prospectively enrolled into the study between January 2009 and July 2013. After initial evaluation with standard tests (ECG, echocardiography, hs-TnT) and provisional exclusion of acute myocardial infarction (AMI) in coronary angiogram, patients were referred for CMR with the suspicion of myocarditis or Takotsubo cardiomyopathy (TTC). According to the result of CMR, patients were reclassified as having myocarditis, AMI, TTC, or non-injured myocardium as assessed by late gadolinium enhancement.

RESULTS

Out of 5110 patients admitted with ACS, 75 had normal coronary angiograms and entered the study; 69 of them (92%) were suspected for myocarditis and 6 (8%) for TTC. After CMR, 49 patients were finally diagnosed with myocarditis (65%), 3 with TTC (4%), 7 with AMI (9%), and 16 (21%) with non-injured myocardium. The provisional diagnosis was changed or excluded in 23 patients (31%), with a 9% rate of unrecognized AMI.

CONCLUSIONS

The study results suggest that the evaluation of patients with ACS and culprit-free angiogram should be complemented by a CMR examination, if available, because the initial work-up with non-CMR tests leads to a significant proportion of misdiagnosed AMI.

Normal coronary myocardial infarct is innocent or guilty? A case of ventricular septal rupture secondary to normal coronary myocardial infarction

Prognosis of cases of myocardial infarction with normal coronary arteries (MINCA) is known to be better than acute myocardial infarction cases with obstructive coronary lesions. A MINCA case causing ventricular septal rupture is rare. Herein, we present a 70-year-old female MINCA case which caused ventricular septal rupture which is a fatal complication of acute myocardial infarction. <Learning objective: Acute myocardial infarction, whether it is atherosclerotic or non atherosclerotic, has a high mortality rate when complicated with ventricular septal rupture. Complications of acute myocardial infarction should be observed cautiously and specific risk factors for ventricular septal rupture need to be investigated.>.

The characterisation and risk factors of ischaemic heart disease in patients with coeliac disease

BACKGROUND

Studies have shown an increased risk of ischaemic heart disease (IHD) in patients with coeliac disease (CD), despite the patients' lack of traditional IHD risk factors.

AIM

To characterise IHD according to CD status.

METHODS

Data on duodenal or jejunal biopsies were collected in 2006-2008 from all 28 pathology departments in Sweden and were used to define CD (equal to villous atrophy; Marsh stage 3). We used the Swedish cardiac care register SWEDEHEART to identify IHD and to obtain data on clinical status and risk factors at time of first myocardial infarction for this case-only comparison. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). CD patients were compared with general population reference individuals.

RESULTS

We identified 1075 CD patients and 4142 reference individuals with subsequent IHD. CD patients with myocardial infarction had lower body mass index (P < 0.001) and cholesterol values (P < 0.001) and were less likely to be active smokers (OR = 0.74; 95% CI = 0.56-0.98) than reference individuals with myocardial infarction. CD patients had less extensive coronary artery disease at angiography (any stenosis: OR = 0.80; 95% CI = 0.66-0.97; three-vessel disease: OR = 0.73; 95% CI = 0.57-0.94); but there was no difference in the proportions of CD patients with positive biochemical markers of myocardial infarction (CD: 92.2% vs. reference individuals: 91.5%, P = 0.766).

CONCLUSION

Despite evidence of an increased risk of IHD and higher cardiovascular mortality, patients with coeliac disease with IHD have a more favourable cardiac risk profile compared with IHD in reference individuals.