Helicobacter pylori and Pro-Inflammatory Protein Biomarkers in Myocardial Infarction with and without Obstructive Coronary Artery Disease

Myocardial infarction (MI) with obstructive coronary artery disease (MI-CAD) and MI in the absence of obstructive coronary artery disease (MINOCA) affect different populations and may have separate pathophysiological mechanisms, with greater inflammatory activity in MINOCA compared to MI-CAD. Helicobacter pylori (Hp) can cause systemic inflammation and has been associated with cardiovascular disease (CVD). We aimed to investigate whether Hp infection is associated with concentrations of protein biomarkers of inflammation and CVD. In a case-control study, patients with MINOCA (n = 99) in Sweden were included, complemented by matched subjects with MI-CAD (n = 99) and controls (n = 100). Protein biomarkers were measured with a proximity extension assay in plasma samples collected 3 months after MI. The seroprevalence of Hp and cytotoxin-associated gene A (CagA) was determined using ELISA. The associations between protein levels and Hp status were studied with linear regression. The prevalence of Hp was 20.2%, 19.2%, and 16.0% for MINOCA, MI-CAD, and controls, respectively (p = 0.73). Seven proteins were associated with Hp in an adjusted model: tissue plasminogen activator (tPA), interleukin-6 (IL-6), myeloperoxidase (MPO), TNF-related activation-induced cytokine (TRANCE), pappalysin-1 (PAPPA), soluble urokinase plasminogen activator receptor (suPAR), and P-selectin glycoprotein ligand 1 (PSGL-1). Hp infection was present in one in five patients with MI, irrespective of the presence of obstructive CAD. Inflammatory proteins were elevated in Hp-positive subjects, thus not ruling out that Hp may promote an inflammatory response and potentially contribute to the development of CVD.

Health-related quality-of-life up to one year after myocardial infarction with non-obstructive coronary arteries

AIMS

Patients with Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) are a heterogenous group and previous studies indicate a decreased Health-related quality-of-life (HRQoL) compared with patients with myocardial infarction with obstructive coronary artery disease and healthy individuals. However, longitudinal data are scarce. Therefore, the aim was to explore HRQoL among patients with MINOCA during a one-year period after the acute event in comparison with a group of healthy individuals and to describe HRQoL in patients with Takotsubo Syndrome (TTS).

METHODS AND RESULTS

Patients with MINOCA were recruited from five hospitals in the Stockholm region (SMINC-2 study, clinical trials: NCT2318498). Patients responded to the HRQoL questionnaire RAND-36 between days 2-4, after 6 and 12 months respectively. A sample of population-based individuals was used as a comparison group. A total of 142 MINOCA patients, (70% women) mean age of 56 years, responded. A population-based sample of 317 volunteers (66% women) mean age of 57 years. Patients with MINOCA scored lower than the comparison group in the domains role functioning physical, social functioning, and role functioning emotional (P = 0.01-0.02) at 12 months. In these domains of HRQoL there was no improvement in MINOCA patients during 12 months follow-up. In the domains of energy/fatigue vitality and emotional well-being the scores improved and were similar to the comparison group at 12 months. Patients with TTS scored generally lower on RAND-36 than MINOCA patients without TTS.

CONCLUSION

Physical, social, and emotional functioning did not improve during the first year after MINOCA, indicating a need for increased follow-up including psychological support.

Coronary microvascular dysfunction in Takotsubo syndrome and associations with left ventricular function

AIMS

Coronary microvascular dysfunction (CMD) has been proposed as an important pathophysiological mechanism in Takotsubo syndrome (TTS). Our aims were (i) to evaluate and compare levels of CMD in patients with TTS and patients with ischaemia and no obstructive coronary arteries (INOCA) and (ii) to investigate associations between CMD and clinical parameters, left ventricular function, and coronary atherosclerosis in TTS.

METHODS AND RESULTS

We conducted a prospective study of 27 female TTS patients and an equally sized, age- and gender-matched, cohort of INOCA patients. Coronary microvascular function was quantified invasively using the index of microcirculatory resistance (IMR), coronary flow reserve (CFR), and resistive reserve ratio (RRR). CMD was defined as IMR ≥ 25 and/or CFR ≤ 2. In the TTS patients, left ventricular function was assessed with echocardiography and cardiovascular magnetic resonance (CMR) imaging, and coronary atherosclerosis was visualized with intravascular ultrasound with near-infrared spectroscopy (IVUS-NIRS). The incidence of CMD was higher in the TTS patients than in the INOCA cohort (78% vs. 44%, P = 0.01), with higher IMR (30 vs. 14, P = 0.002), lower CFR (1.8 vs. 2.8, P = 0.009), and lower RRR (2.1 vs. 3.5, P = 0.003). In apical compared with midventricular TTS, IMR was numerically higher (50 vs. 28, P = 0.20), whereas CFR and RRR were lower (1.5 vs. 2.5, P = 0.003 and 1.6 vs. 2.7, P = 0.01, respectively). Global longitudinal strain and global circumferential strain, assessed with CMR imaging, were more impaired in apical than in midventricular TTS (-11 vs. -14, P < 0.001 and -12 vs. -15, P = 0.049, respectively). In the TTS patients, CFR and RRR correlated with echocardiography-derived (R²  = 0.15, P = 0.002 and R²  = 0.18, P = 0.007, respectively) and CMR-derived (R²  = 0.09, P = 0.025 and R²  = 0.10, P = 0.038, respectively) ejection fraction. CFR and RRR correlated inversely with CMR-derived end-diastolic volume index, end-systolic volume index, and left ventricular mass index. IMR, CFR, and RRR were not associated with measures of coronary atherosclerosis derived by IVUS-NIRS.

CONCLUSIONS

Coronary microvascular dysfunction is common in patients with TTS and more frequent than in patients with INOCA. CMD in TTS is more severe in the apical compared with the midventricular phenotype of the syndrome, is associated with left ventricular function, but is unrelated to coronary atherosclerosis. Our results support the notion of CMD as a key mediator in TTS.

Rationale and design of BROKEN-SWEDEHEART: a registry-based, randomized, parallel, open-label multicenter trial to test pharmacological treatments for broken heart (takotsubo) syndrome

BACKGROUND

Takotsubo syndrome (TS) is a life-threatening acute heart failure syndrome without any evidence-based treatment options. No treatment for TS has been examined in a randomized trial.

STUDY DESIGN AND OBJECTIVES

BROKEN-SWEDEHEART is a multicenter, randomized, open-label, registry-based 2 × 2 factorial clinical trial in patients with TS designed to test whether treatment with adenosine and dipyridamole accelerates cardiac recovery and improves clinical outcomes compared to standard care (study 1); and apixaban reduces the risk of thromboembolic events compared to no treatment with antithrombotic drugs (study 2). The trial will enroll 1,000 patients. Study 1 (adenosine hypothesis) will evaluate 2 coprimary end points: (1) wall motion score index at 48 to 96 hours (evaluated in the first 200 patients); and (2) the composite of death, cardiac arrest, need for mechanical assist device or heart failure hospitalization within 30 days or left ventricular ejection fraction <50% at 48 to 96 hours (evaluated in 1,000 patients). The primary end point in study 2 (apixaban hypothesis) is the composite of death or thromboembolic events within 30 days or the presence of intraventricular thrombus on echocardiography at 48 to 96 hours.

CONCLUSIONS

BROKEN-SWEDEHEART will be the first prospective randomized multicenter trial in patients with TS. It is designed as 2 parallel studies to evaluate whether adenosine accelerates cardiac recovery and improves cardiac function in the acute phase and the efficacy of anticoagulation therapy for preventing thromboembolic complications in TS. If either of its component studies is successful, the trial will provide the first evidence-based treatment recommendation in TS.

CLINICAL TRIALS IDENTIFIER

The trial has been approved by the Swedish Medicinal Product Agency and the Swedish Ethical Board and is registered at ClinicalTrials.gov (NCT04666454).

Antiphospholipid antibodies in patients with myocardial infarction with and without obstructive coronary arteries

BACKGROUND

Recent studies demonstrate that prothrombotic antiphospholipid antibodies (aPL) are overrepresented in patients with myocardial infarction (MI) due to coronary artery disease (MICAD). However, it is not known whether aPL differ between the two subsets of MI: MICAD and MI with nonobstructive coronary arteries (MINOCA).

OBJECTIVES

To determine whether aPL are associated with MINOCA or MICAD, or with hypercoagulability as assessed by activated protein C-protein C inhibitor (APC-PCI) complex.

METHODS

Well-characterized patients with MINOCA (n = 98), age- and gender-matched patients with MICAD (n = 99), and healthy controls (n = 100) were included in a cross-sectional case-control study. Autoantibodies (IgA/G/M) targeting cardiolipin and β₂ glycoprotein-I and specific nuclear antigens were analyzed by multiplexed bead technology. The concentration of APC-PCI was determined as a measure of hypercoagulability by an immunofluorometric sandwich assay.

RESULTS

Both prevalence and titers of aPL of the IgG isotype (anti-cardiolipin and/or anti-β₂ glycoprotein-I) were higher in patients with MINOCA and MICAD than in controls. aPL IgG positivity was twice as frequent among patients with MICAD than MINOCA (11% vs. 6%, nonsignificant). We observed no group differences regarding aPL IgA/M or antibodies targeting specific nuclear antigens. Levels of APC-PCI were elevated in aPL IgG-positive compared to aPL IgG-negative MICAD patients.

CONCLUSIONS

aPL IgG, but not IgA/M, are enriched particularly in patients with MICAD but also in patients with MINOCA, as compared to controls. Interestingly, signs of hypercoagulability-measured by increased levels of the APC-PCI complex-were present in aPL IgG-positive MICAD patients, indicating an association with functional disturbances of the coagulation system.

Plasma catecholamine levels in the acute and subacute stages of takotsubo syndrome: Results from the Stockholm myocardial infarction with normal coronaries 2 study

AIMS

It is well-accepted that takotsubo syndrome (TS) is characterized by a massive surge of plasma catecholamines despite lack of solid evidence. The objective of this study was to examine the hypothesis of a massive catecholamine elevation in TS by studying plasma-free catecholamine metabolites in patients participating in the Stockholm myocardial infarction (MI) with normal coronaries 2 (SMINC-2) study where TS constituted more than one third of the patients.

METHODS AND RESULTS

The patients included in the SMINC-2 study were classified, according to cardiac magnetic resonance (CMR) imaging findings (148 patients), which was performed at a median of 3 days after hospital admission. Plasma-free catecholamine metabolites; metanephrine, normetanephrine, and methoxy-tyramine were measured on day 2-4 after admission. Catecholamine metabolite levels were available in 125 patients. One hundred and ten (88%) of the 125 patients included in SMINC-2 study, and 38 (86.4%) of the 44 patients with TS had completely normal plasma metanephrine and normetanephrine levels. All patients had normal plasma methoxy-tyramine levels. Fourteen (11.2%) of the 125 patients included in SMINC-2 study, and 5 (11.6%) of the 43 patients with TS had mild elevations (approximately 1.2 times the upper normal limits) of either plasma metanephrine or normetanephrine. One patient with pheochromocytoma-triggered TS had marked elevation of plasma metanephrine and mild elevation of plasma normetanephrine. There were no significant differences between the number or degree of catecholamine metabolite elevations between the different groups of patients with CMR imaging diagnosis included in SMINC-2 study.

CONCLUSION

There was no evidence of massive catecholamine elevations in the acute and subacute stages of TS apart from one patient with pheochromocytoma-induced TS. Most of the TS patients had normal catecholamine metabolites indicating that blood-borne catecholamines do not play a direct role in the pathogenesis of TS.

Short- and Long-Term Clinical Outcomes for Patients With Takotsubo Syndrome and Patients With Myocardial Infarction: A Report From the Swedish Coronary Angiography and Angioplasty Registry

Background

Takotsubo syndrome (TS) is a potentially life‐threatening acute cardiac syndrome with a clinical presentation similar to myocardial infarction and for which the natural history, management, and outcome remain incompletely understood. Our aim was to assess the relative short‐term mortality risk of TS, ST‐segment–elevation myocardial infarction (STEMI), and non‐STEMI (NSTEMI) and to identify predictors of in‐hospital complications and poor prognosis in patients with TS.

Methods and Results

This is an observational cohort study based on the data from the SCAAR (Swedish Coronary Angiography and Angioplasty Registry). We included all patients (n=117 720) who underwent coronary angiography in Sweden attributed to TS (N=2898 [2.5%]), STEMI (N=48 493 [41.2%]), or NSTEMI (N=66 329 [56.3%]) between January 2009 and February 2018. We compared patients with TS to those with NSTEMI or STEMI. The primary end point was all‐cause mortality at 30 days. Secondary outcomes were acute heart failure (Killip Class ≥2) and cardiogenic shock (Killip Class 4) at the time of angiography. Patients with TS were more often women compared with patients with STEMI or NSTEMI. TS was associated with unadjusted and adjusted 30‐day mortality risks lower than STEMI (adjusted hazard ratio [adjHR], 0.60; 95% CI, 0.48–0.76; P<0.001), but higher than NSTEMI (adjHR, 2.70; 95% CI, 2.14–3.41; P<0.001). Compared with STEMI, TS was associated with a similar risk of acute heart failure (adjHR, 1.26; 95% CI, 0.91–1.76; P=0.16) but a lower risk of cardiogenic shock (adjHR, 0.55; 95% CI, 0.34–0.89; P=0.02). The relative 30‐day mortality risk for TS versus STEMI and NSTEMI was higher for smokers than nonsmokers (adjusted P interaction STEMI=0.01 and P interaction NSTEMI=0.01).

Conclusions

The 30‐day mortality rate in TS was higher than in NSTEMI but lower than STEMI despite a similar risk of acute heart failure in TS and STEMI. Among patients with TS, smoking was an independent predictor of mortality.

Early Comprehensive Cardiovascular Magnetic Resonance Imaging in Patients With Myocardial Infarction With Nonobstructive Coronary Arteries

OBJECTIVES

The objective of the SMINC-2 (Stockholm Myocardial Infarction With Normal Coronaries 2) study was to determine if more than 70% of patients with myocardial infarction with nonobstructed coronary arteries (MINOCA), investigated early with comprehensive cardiovascular magnetic resonance (CMR), could receive a diagnosis entirely by imaging.

BACKGROUND

The etiology of MINOCA is heterogeneous, including coronary, cardiac, and noncardiac causes. Patients with MINOCA, therefore, represent a diagnostic challenge where CMR is increasingly used.

METHODS

The SMINC-2 study was a prospective study of 148 patients with MINOCA imaged with 1.5-T CMR with T₁ and extracellular volume mapping early after hospital admission, compared to 150 patients with MINOCA imaged using 1.5-T CMR without mapping techniques from the SMINC-1 study as historic controls.

RESULTS

CMR was performed at a median of 3 (SMINC-2) versus 12 (SMINC-1) days after hospital admission. In total, 77% of patients received a diagnosis with CMR imaging in the SMINC-2 study compared to 47% in the SMINC-1 study (p < 0.001). Compared to SMINC-1, CMR in SMINC-2 detected higher proportions of myocarditis (17% vs. 7%; p = 0.01) and takotsubo syndrome (35% vs. 19%; p = 0.002) but similar proportions of myocardial infarction (22% vs. 19%; p = 0.56) and other cardiomyopathies (3% vs. 2%; p = 0.46).

CONCLUSIONS

The results of the SMINC-2 study show that 77% of all patients with MINOCA received a diagnosis when imaged early with CMR, including advanced tissue characterization, which was a considerable improvement in comparison to the SMINC-1 study. This supports the use of early CMR imaging as a diagnostic tool in the investigation of patients with MINOCA. (Stockholm Myocardial Infarction With Normal Coronaries [SMINC]-2 Study on Diagnosis Made by Cardiac MRI [SCMINC-2]; NCT02318498).

Increased Inflammatory Activity in Patients 3 Months after Myocardial Infarction with Nonobstructive Coronary Arteries

BACKGROUND

Around 5%-10% of patients with myocardial infarction (MI) present with nonobstructive coronary arteries (MINOCA). We aimed to assess pathophysiological mechanisms in MINOCA by extensively evaluating cardiovascular biomarkers in the stable phase after an event, comparing MINOCA patients with cardiovascular healthy controls and MI patients with obstructive coronary artery disease (MI-CAD).

METHODS

Ninety-one biomarkers were measured with a proximity extension assay 3 months after MI in 97 MINOCA patients, 97 age- and sex-matched MI-CAD patients, and 98 controls. Lasso analyses (penalized logistic regression models) and adjusted multiple linear regression models were used for statistical analyses.

RESULTS

In the Lasso analysis (MINOCA vs MI-CAD), 8 biomarkers provided discriminatory value: P-selectin glycoprotein ligand 1, C-X-C motif chemokine 1, TNF-related activation-induced cytokine, and pappalysin-1 (PAPPA) with increasing probabilities of MINOCA, and tissue-type plasminogen activator, B-type natriuretic peptide, myeloperoxidase, and interleukin-1 receptor antagonist protein with increasing probabilities of MI-CAD. Comparing MINOCA vs controls, 7 biomarkers provided discriminatory value: N-terminal pro-B-type natriuretic peptide, renin, NF-κ-B essential modulator, PAPPA, interleukin-6, and soluble urokinase plasminogen activator surface receptor with increasing probabilities of MINOCA, and agouti-related protein with increasing probabilities of controls. Adjusted multiple linear regression analyses showed that group affiliation was associated with the concentrations of 7 of the 8 biomarkers in the comparison MINOCA vs MI-CAD and 5 of the 7 biomarkers in MINOCA vs controls.

CONCLUSIONS

Three months after the MI, the biomarker concentrations indicated greater inflammatory activity in MINOCA patients than in both MI-CAD patients and healthy controls, and a varying degree of myocardial dysfunction among the 3 cohorts.

Takotsubo twins

Takotsubo syndrome is an intriguing condition of often stress induced reversible cardiac dysfunction mimicking myocardial infarction, but without explanatory coronary obstructions. The pathogenesis of the syndrome is not yet fully understood, though altered sympathetic regulation or response to cardiac sympathetic stimuli is likely to be involved. We present a unique and clinically detailed report of identical twin sisters, who both developed Takotsubo syndrome in association to mental stress shortly after menopause, also covering a potential relapse of disease in one of the twins, supporting the theory of a genetic contribution to the development of the syndrome proposed by previous case reports and small genetic studies.

Personality Traits in Patients with Myocardial Infarction with Nonobstructive Coronary Arteries

OBJECTIVE

The purpose of this study was to describe type A behavior pattern and trait anger in patients with myocardial infarction with nonobstructive coronary arteries (MINOCA) and compare them with patients with coronary heart disease and healthy controls. Type A behavior pattern and anger have been linked to coronary heart disease in previous studies. This is the first study to assess type A behavior pattern and trait anger in MINOCA patients.

METHODS

One hundred MINOCA patients, consecutively recruited during 2007-2011 at 5 coronary care units in Stockholm, were matched for sex and age to 100 coronary heart disease patients and 100 healthy controls. All participants completed the Bortner Rating Scale to quantify type A behavior pattern and the Spielberger Trait Anger Scale to quantify anger 3 months after the acute event.

RESULTS

MINOCA patients' Bortner Rating Scale score was 70.9 ± 10.8 (mean ± SD) and Spielberger Trait Anger Scale score was 14 (12-17) (median; interquartile range). Coronary heart disease patients' Bortner Rating Scale score was 70.5 ± 10.2 and Spielberger Trait Anger Scale score was 14 (12-17). Healthy controls' Bortner Rating Scale score was 71.9 ± 9.1 and Spielberger Trait Anger Scale score was 13 (11-16).

CONCLUSION

We found no significant differences in Bortner Rating Scale score and Spielberger Trait Anger Scale score among MINOCA, coronary heart disease patients, and healthy controls, regardless of whether total scores, subscales, or cutoffs were used to classify type A behavior pattern and trait anger. However, we cannot exclude the existence of an occasional episode of anger or mental stress in relation to the coronary event. This is the first study to assess type A behavior pattern and trait anger in patients with MINOCA, and future studies need to confirm the current findings before any firm conclusions can be made.

Outcome and selection of revascularization strategy in left main coronary artery stenosis

OBJECTIVES

To investigate clinical outcome in unselected real-life patients with unprotected left main coronary artery (ULMCA) stenosis and determine factors associated with selection of revascularization strategy.

DESIGN

Consecutive patients with ULMCA stenosis at our institution in 2009-2013 (n = 308) were retrospectively analyzed with propensity score adjusted Cox proportional hazards models for outcome. Baseline characteristics in relation to selection of revascularization strategy were analyzed with multivariate logistic regression.

RESULTS

Patients that underwent PCI (n = 94) had a higher risk of major adverse cardiac and cerebrovascular events (MACCE; adjusted HR 2.13 [95% CI 1.08-4.19]) than patients that had CABG surgery but there was no difference in the combination of death and MI (adjusted HR 1.17 [95% CI 0.50-2.75]). Later year of index angiography, age, Euroscore II and angiographer favoring PCI was associated with PCI as revascularization strategy. Higher SYNTAX score, higher systolic blood pressure and angiographer favoring CABG was associated with CABG.

CONCLUSIONS

In consecutive patients with ULMCA stenosis PCI is associated with higher MACCE rates than CABG but there is no difference in death and MI. Later year of index angiography, higher age, lower systolic blood pressure, higher predicted per-procedural surgical risk, less complex coronary anatomy and angiographer favoring PCI increased the probability of revascularization with PCI instead of CABG.

Effect of Myocardial Infarction With Nonobstructive Coronary Arteries on Physical Capacity and Quality-of-Life

Patients with myocardial infarction with nonobstructive coronary arteries (MINOCA), including Takotsubo syndrome (TS), are considered to have a better survival compared with those with coronary heart disease (CHD). Studies of patients with MINOCA measuring physical and mental function including matched control groups are lacking. The aim of this study was to determine the physical capacity and quality of life in patients with MINOCA. One-hundred patients with MINOCA along with TS (25%) were investigated from 2007 to 2011. A bicycle exercise stress test was performed 6 weeks after hospitalization and QoL was investigated by the Short Form Survey 36 at 3 months' follow-up. Both a healthy and a CHD group that were age and gender matched were used as controls. The MINOCA group had a lower physical capacity (139 ± 42 W) compared with the healthy control group (167 ± 53 W, p <0.001) but better than the CHD control group (124 ± 39 W, p = 0.023). Patients with MINOCA had lower physical and mental component summary scores compared with the healthy controls (p <0.001) and lower mental component summary (p = 0.012), mental health (p = 0.016), and vitality (p = 0.008) scores compared with the CHD controls. In conclusion, the findings of this first study on exercise capacity and QoL in patients with MINOCA showed both physical and mental distress from 6 weeks to 3 months after the acute event similar to CHD controls and in some perspectives even lower scores especially in the mental component of QoL.

The value of a new cardiac magnetic resonance imaging protocol in Myocardial Infarction with Non-obstructive Coronary Arteries (MINOCA) - a case-control study using historical controls from a previous study with similar inclusion criteria

Background

Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) is common with a prevalence of 6% of all patients fulfilling the diagnosis of myocardial infarction. MINOCA should be considered a working diagnosis. Cardiac Magnetic Resonance (CMR) imaging has recently been suggested to be of great value to determine the cause behind MINOCA. The objectives of this paper are to describe the rationale behind the second Stockholm Myocardial Infarction with Normal Coronaries (SMINC-2) study and to discuss the protocol for investigation of MINOCA patients in the light of the recently published position paper from the European Society of Cardiology.

Methods

The SMINC-2 study is an open non-randomised study using historical controls for comparison. The primary aim is to prove that MINOCA patients investigated with the latest CMR imaging technique can achieve a diagnosis in 70% of all cases entirely by imaging. By including 150 patients we will have >80% chance to prove that the diagnostic accuracy can be improved by 20 absolute % with a p-value of less than 0.05 when compared with CMR imaging in the SMINC-1 study. Furthermore, in addition to invasive coronary angiography, coronary arteries are evaluated by computed tomography angiography to investigate coronary causes and questionnaires are used to describe Quality-of-Life (QoL). By January 1st 2017, 75 patients have been included.

Discussion

Whether CMR imaging can provide a diagnosis to an adequate proportion of MINOCA patients is unknown. Well-defined inclusion and exclusion criteria will be used to compare a MINOCA cohort from the population with an appropriate control group. Positive results are likely to influence future guidelines of the management of MINOCA. Furthermore, the study will give mechanistic insights into MINOCA in particular in patients with “true” myocardial infarction and describe QoL in this vulnerable group of patients.

Trial registration

Clinical Trials NCT02318498.

Plasma biomarker levels and non-obstructive coronary artery disease determined by coronary computed tomography angiography

PURPOSE

Coronary computed tomography angiography (CTA) and several circulating biomarkers have prognostic value regarding cardiovascular disease (CVD) events, but their association is incompletely studied. We aimed to investigate whether markers of lipid metabolism, inflammation and kidney function could predict non-obstructive coronary artery disease (CAD) determined by coronary CTA, in a low-to-intermediate-risk group.

METHODS

Coronary CTA and laboratory testing were performed for 115 subjects (45-70 years), with low prevalence of CVD risk factors, predominantly low-to-intermediate Framingham risk and normal or mildly reduced kidney function.

RESULTS

Forty-nine (43%) had no CAD at coronary CTA, and 66 (57%) had CAD in ≥1 segment (stenosis < 50%). Adiponectin was inversely associated with CAD, and lipoprotein(a) and cystatin C were associated with CAD at coronary CTA. In multivariable logistic regression, cystatin C remained an independent predictor of CAD (OR: 2·50, 95% CI: 1·12-5·59). Cystatin C also correlated to the number of diseased segments (r_s  = 0·25, P<0·01).

CONCLUSION

Higher plasma levels of cystatin C were associated with non-obstructive CAD at coronary CTA in subjects with low-to-intermediate CVD risk and normal to mildly reduced kidney function.

Risk Factors and Markers for Acute Myocardial Infarction With Angiographically Normal Coronary Arteries

Myocardial Infarction with normal coronary arteries (MINCA) is common with a prevalence of 1% to 12% of all myocardial infarctions. The pathogenic mechanisms of MINCA are still unknown, but endothelial dysfunction has been suggested as a possible cause. To investigate risk factors and markers for MINCA, we conducted a case-control study. Considering the reported low prevalence of classical risk factors for coronary heart disease (CHD) in some but not all studies, our hypothesis was that endothelial function and intima-media thickness (IMT) were better, respectively lower, than CHD controls. One hundred patients with MINCA fulfilling diagnostic criteria according to the European Society of Cardiology/American Collage of Cardiology/American Heart Association universal definition of myocardial infarction with myocarditis excluded by cardiac magnetic resonance imaging were investigated. Risk factors, endothelial function (EndoPAT), and IMT were compared to gender- and age-matched patients with myocardial infarction and CHD, respectively healthy controls. Smoking, hypertension, impaired glucose tolerance and diabetes mellitus, inflammatory disease, and psychiatric disorders were more common in patients with MINCA than in healthy controls. In contrast to patients with CHD, the lipid profile was antiatherogenic with low low-density lipoprotein and high high-density lipoprotein cholesterol. There were no major differences between the groups regarding endothelial function and IMT that were in the normal range. In conclusion, the present study showed that MINCA was associated with many established cardiovascular risk factors without major differences in atherosclerosis markers. MINCA patients recalled a high prevalence of emotional stress before admission that together with previous psychiatric vulnerability and female gender speaks strongly in favor of Takotsubo syndrome being an important cause of MINCA.

Myocardial infarction with normal coronary arteries is common and associated with normal findings on cardiovascular magnetic resonance imaging: results from the Stockholm Myocardial Infarction with Normal Coronaries study

OBJECTIVES

Myocardial infarction with angiographically normal coronary arteries (MINCA) is an important subtype of myocardial infarction; however, the prevalence, underlying pathophysiology, prognosis and optimal management of this condition are still largely unknown. Cardiovascular magnetic resonance (CMR) imaging has the potential to clarify the underlying pathology in patients with MINCA. The objective of this study was to investigate the diagnostic value of CMR imaging in this group of patients.

DESIGN

The prospective, multicentre, observational Stockholm Myocardial Infarction with Normal Coronaries (SMINC) study.

SETTING

Coronary care units in the Stockholm metropolitan area.

SUBJECTS

Patients between 35 and 70 years of age with MINCA were consecutively included in the screening phase of the SMINC study. All patients had a typical clinical presentation, fulfilling the universal definition of myocardial infarction and had normal coronary angiography finding. Patients with known structural or coronary heart disease or other known causes of elevated troponin levels were excluded.

RESULTS

In total, 176 patients with MINCA were screened from 2007 to 2011. Of these, 152 underwent CMR imaging. The investigation was performed a median of 12 (interquartile range 6-28) days after hospital admission; 67% of the findings were normal, whereas 19% of patients had signs of myocardial necrosis and 7% had signs of myocarditis. The remaining patients (7%) had either unrecognized hypertrophic cardiomyopathy or could not be classified.

CONCLUSION

In this consecutive series of patients with MINCA, CMR imaging may help to differentiate between those with myocarditis, myocardial necrosis and normal myocardium. The incidence of MINCA was higher than previously reported. After excluding cases of myocarditis, MINCA consists of a large group of patients with normal CMR imaging results and a smaller group with myocardial necrosis. The aetiologies of these different imaging findings need to be explored.

Risk factors for myocardial infarction with normal coronary arteries and myocarditis compared with myocardial infarction with coronary artery stenosis

The interest and awareness of myocardial infarction with normal coronary arteries (MINCA) have increased recently due to the frequent use of coronary angiography, the description of Takotsubo stress cardiomyopathy, and new sensitive troponin analyses. The prevalence of MINCA in all patients with myocardial infarction (MI) was registered during a 3-month period in the Stockholm metropolitan area in Sweden. The results showed that MINCA is more common than previously thought (7%) and affecting one third of every woman with MI. Patients with myocarditis were younger and more often presented with signs of inflammation such as elevated C-reactive protein and fever. Myocarditis constitutes an important differential diagnosis for coronary artery disease. There is a need for larger studies of MINCA, including investigation with cardiac magnetic resonance imaging, to establish prevalence and pathological process in this important subgroup of MI.