Could time trends in myocardial infarction incidence be due to diagnostic inconsistency? A study of the validity of hospital discharge diagnoses

Interleukin 6 trans-signalling and risk of future cardiovascular events

Aims

The pro-inflammatory response to interleukin 6 (IL6) trans-signalling in atherosclerosis is driven by the IL6 and soluble IL6 receptor (sIL6R) binary complex. The binary IL6:sIL6R complex is inactivated by sgp130 through the formation of the ternary IL6:sIL6R:sgp130 complex. The aim of this study was to investigate if IL6 trans-signalling, estimated by a ratio between the binary and ternary complexes, associates with the risk of future cardiovascular events (CVE) in a Swedish cohort of 60-year-old men and women (n = 4232).

Methods and results

Binary and ternary complex levels expressed in nanomol/Litre were derived from serum concentrations of IL6, sIL6R, and sgp130. Cox regression models were used to assess the risk of CVE (myocardial infarction, angina pectoris, and ischaemic stroke, n = 525), expressed as hazard ratio (HR) with 95% confidence interval (CI), associated with increasing circulating levels of the three molecules and with the binary/ternary complex ratio. Estimates were adjusted for the common cardiovascular (CV) risk factors. To assess the level of IL6-trans-signalling, we estimated the binary/ternary complex ratio and then analysed the association with CVE risk. A ratio higher than the median, representing a relative excess of the active binary complex was associated with increased CVE risk (adjusted HR 1.44, 95% CI 1.21-1.72).

Conclusion

The ratio between the functional moieties of IL6 trans-signalling, IL6:sIL6R, and IL6:sIL6R:sgp130, was associated with CVE risk indicating that it could be a promising marker of CV risk and possibly be used in selecting patients for anti-inflammatory therapy.

Unrecognized myocardial infarction assessed by cardiac magnetic resonance imaging is associated with adverse long-term prognosis

Background

Unrecognized myocardial infarctions (UMIs) are common. The study is an extension of a previous study, aiming to investigate the long-term (>5 year) prognostic implication of late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) detected UMI in patients with suspected stable coronary artery disease (CAD) without previously diagnosed myocardial infarction (MI).

Methods

In 235 patients with suspected stable CAD without previous MI, LGE-CMR imaging and coronary angiography were performed. LGE with a subendocardial component detectable in more than one imaging plane was required to indicate UMI. The stenosis grade of the coronary arteries was determined, including in the artery supplying an infarcted area. Stenosis ≥70% stenosis was considered significant. Patients were followed for 5.4 years in mean regarding a composite endpoint of cardiovascular death, MI, hospitalization due to heart failure, stable or unstable angina.

Results

UMI were present in 58 of 235 patients (25%). Thirty-nine of the UMIs were located downstream of a significant coronary stenosis. During the follow-up 40 patients (17.0%) reached the composite endpoint. Of patients with UMI, 34.5% (20/58) reached the primary endpoint compared to 11.3% (20/177) of patients with no UMI (HR 3.7, 95% CI 2.0–6.9, p<0.001). The association between UMI and outcome remained (HR 2.3, 95% CI 1.2–4.4, p = 0.012) after adjustments for age, gender, extent of CAD and all other variables univariate associated with outcome. Sixteen (41%) of the patients with an UMI downstream of a significant stenosis reached the endpoint compared to four (21%) patients with UMI and no relation to a significant stenosis (HR 2.4, 95% CI 0.8–7.2, p = 0.12).

Conclusion

The presence of UMI was independently associated with an increased risk of cardiovascular events during long-term follow up.

Prognosis in relation to high-sensitivity cardiac troponin T levels in patients with myocardial infarction and non-obstructive coronary arteries

BACKGROUND

Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) is a recently recognized condition where biomarkers and prognosis are less well studied than in MI with obstructive coronary artery disease (MI-CAD). We therefore aimed to investigate the one-year prognostic value of high-sensitivity cardiac troponin T (hs-cTnT) levels in MINOCA in comparison to MI-CAD.

METHODS

In this registry-based cohort study, we used data from patients with a discharge diagnosis of MI, admitted between 2009 and 2013 to Swedish hospitals using the hs-cTnT assay. Only patients without previously known coronary artery disease were considered. Patients with and without coronary stenosis >50% were regarded to have MI-CAD and MINOCA, respectively. Assessed outcomes included all-cause mortality, cardiovascular (CV) mortality and major CV events (MACE), defined as the composite of CV death or admissions for non-fatal MI, heart failure (HF) or ischemic stroke.

RESULTS

The study cohort consisted of 1639 MINOCA and 17,304 MI-CAD patients. In adjusted analyses, hs-cTnT (ln) in MINOCA patients predicted all-cause mortality (HR 1.32 [95% CI 1.11-1.56]), CV mortality (HR 2.11 [95% CI 1.51-2.96]) and MACE (HR 1.44 [95% CI 1.20-1.72]). Hs-cTnT (ln) also predicted readmissions for HF (HR 1.51 [95% CI 1.51-2.96]) but not non-fatal MI or stroke. Interaction analyses suggested that hs-cTnT (ln) was at least as prognostic in patients with MINOCA compared to MI-CAD.

CONCLUSIONS

Hs-cTnT levels in MINOCA patients are strong and independent predictors of adverse outcome. Consideration of hs-cTnT levels is important for risk assessment of MINOCA patients.

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.

The feasibility of routine mortality and morbidity register data linkage to study the occurrence of acute coronary heart disease events in Finland. The Finnish Cardiovascular Diseases Registers (CVDR) Project

Validated population-based data on the occurrence of coronary heart disease in Finland have previously been obtained from myocardial infarction (MI) registers. Such registers cannot, however, cover large areas. Therefore, the Finnish Cardiovascular Diseases Registers (CVDR) Project was set up to obtain data for the whole of Finland. The CVDR Project is based on routine mortality and morbidity data linkage. We report here the overall approach used in the project, the results of the feasibility study and the first main results. In Finland, data on all hospitalizations are registered in the nationwide Hospital Discharge Register. Also, data on all deaths are collected in the nationwide Causes of Death Register. The unique personal identification number assigned to all persons residing in Finland was used for data linkage. Data have been validated using the FINMONICA MI registers. Sensitivity analyses showed that the data were robust and consistent between different geographical areas. Coronary heart disease (CHD) mortality as well as the incidence and event rates showed the same very clear geographical pattern, dividing Finland to a southwest area with a lower occurrence and a northeast area with nearly twice higher occurrence. Case fatality did not differ much between the areas and did not follow this Southwest-Northeast division. The differences between northeast and southwest Finland may be related to differences in risk factor levels but also to socioeconomic and genetic differences. The CVDR Project data will be instrumental in further research addressing these issues.