Familial risk of myocardial infarction with non-obstructive and obstructive coronary arteries -A nation-wide cohort study.

BACKGROUND AND AIMS: The familial risk among patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) is unknown. Previous studies of family history in myocardial infarction (MI), have not made a distinction between MINOCA and MI due to coronary artery disease (MI-CAD), based on angiographic findings. We therefore sought to investigate familial risk of MI without and with obstructive coronary arteries. METHODS: Register-based cohort study with a total of 15,462 MINOCA cases, 204,424 MI-CAD cases, 38,220 control subjects without MI and with non-obstructive coronary arteries. First-degree relatives were identified 1995-2020. Cox proportional hazard regression models were used to compare familial risk in MINOCA and MI-CAD with control subjects. RESULTS: During a mean follow-up of 8.1 ± 4.2 years, MINOCA occurred in 1.0% of first-degree relatives with MINOCA whereas MI-CAD occurred in 9.7% of first-degree relatives of MINOCA. The age- and sex-adjusted hazard ratio (HR) for a MINOCA-relative experiencing MINOCA and MI-CAD, compared to control subjects, was 0.99 (95% confidence interval [CI] 0.80-1.23) and 1.10 (95% CI 1.03-1.18), respectively. During a mean follow-up of 8.5 ±4.8 years, MI-CAD occurred in 12.2% of first- degree relatives with MI-CAD with age- and sex-adjusted HR 1.43 (95% CI 1.37-1.49). CONCLUSIONS: No increased familial risk of MINOCA was observed for MINOCA-patients whereas there was an increased familial risk for MI-CAD when compared to control subjects. These results may indicate that genetic factors and shared environmental factors within a family leading to CAD are important also for MINOCA, thus MI-CAD and MINOCA could share underlying mechanisms.

It is unknown whether a familial risk of myocardial infarction is important for developing myocardial infarction without obstructive coronary arteries (MINOCA). In our study we observed an increased familial occurrence for myocardial infarction with obstructive coronary artery disease (MI-CAD) when compared to control subjects whereas no increased familial occurrence of MINOCA was seen among MINOCA patients. These results may indicate that genetic factors and shared environmental factors within a family leading to CAD are important also for MINOCA, thus MI-CAD and MINOCA could share underlying mechanisms.

Prevalence and prognostic implications of myocardial injury in patients with influenza.

Aims: Influenza may cause myocardial injury and trigger acute cardiovascular events. The aim of this study was to investigate the prevalence and prognostic implications of elevated high-sensitivity cardiac troponin I (hs-cTnI) in patients with influenza. Methods and results: In this prospective cohort study, we consecutively enrolled patients with influenza-like illness from two emergency departments in Sweden during three seasons of influenza, 2017-20. Ongoing Influenza infection was diagnosed by polymerase chain reaction and blood samples were collected for later analysis of hs-cTnI. All patients were followed-up for a composite endpoint of major adverse cardiovascular events (MACE) including death, myocardial infarction, unstable angina, heart failure, atrial fibrillation, and stroke within 1 year. Of the 466 patients with influenza-like symptoms, 181 (39%) were positive for influenza. Fifty (28%) patients were hospitalized. High-sensitivity cTnI was elevated in 11 (6%) patients and 8 (4%) experienced MACE. In univariate analyses, MACE was associated with age [hazard ratio (HR): 1.14, 95% confidence interval (CI): 1.05-1.23], hypertension (HR 5.56, 95%CI: 1.12-27.53), estimated glomerular filtration rate (HR: 0.94, 95%CI: 0.91-0.97), and elevated hs-cTnI (HR: 18.29, 95%CI: 4.57-73.24), N-terminal prohormone of brain natriuretic peptide (HR: 14.21, 95%CI: 1.75-115.5), hs-CRP (HR: 1.01, 95%CI: 1.00-1.02), and white blood cell count (HR: 1.12, 95%CI: 1.01-1.25). In multivariate analysis, elevated hs-cTnI was independently associated with MACE (HR: 4.96, 95%CI: 1.10-22.41). Conclusion: The prevalence of elevated hs-cTnI is low in unselected patients with influenza. Elevated hs-cTnI was associated with poor prognosis. A limitation is that the estimated associations are uncertain due to few events.

Major adverse cardiovascular events following electroconvulsive therapy in depression: A register-based nationwide Swedish cohort study with 1-year follow-up.

BACKGROUND: The cardiovascular response during electroconvulsive therapy (ECT) could induce major adverse cardiovascular events (MACE) in the short-term, while reduced depression could decrease the risk of MACE in the long-term. The balance between these potential effects has not been thoroughly investigated. METHODS: This nationwide, registry-based cohort study included all patients admitted to Swedish hospitals due to moderate or severe unipolar depression between 2011 and 2018. Patients were divided into an ECT group and a non-ECT group, and followed for 1 year. Patients were matched by risk factors for cardiovascular disease by propensity score matching. Cox regression was used to examine the association between ECT and MACE. RESULTS: Out of a total of 28 584 inpatients, 5476 patients who had received ECT were matched to 5476 non-ECT patients. ECT was associated with reduced risk of MACE within 90 days and 1 year. Within 1 year after admission, a total of 127 patients (2.3%) in the non-ECT group and 82 patients (1.4%) in the ECT group had at least one MACE (hazard ratio [HR], 0.65; 95% confidence interval, 0.49-0.85). LIMITATIONS: Real-life observational studies carry risk for residual confounding. CONCLUSIONS: ECT in patients hospitalized for depression was not associated with any significant short-term risks of cardiovascular events. Instead, ECT was associated with a reduced risk of MACE within 1 year after admission compared with patients not treated with ECT. This association may be explained by reduced depressive symptoms after ECT, improved risk factor management in the ECT-group or by residual confounding by indication.

Survival in Patients With Suspected Myocardial Infarction With Nonobstructive Coronary Arteries: A Comprehensive Systematic Review and Meta-Analysis From the MINOCA Global Collaboration.

BACKGROUND: Suspected myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA) occurs in ≈5% to 10% of patients with MI referred for coronary angiography. The prognosis of these patients may differ to those with MI and obstructive coronary artery disease (MI-CAD) and those without a MI (patients without known history of MI [No-MI]). The primary objective of this study is to evaluate the 12-month all-cause mortality of patients with MINOCA. METHODS: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the terms "MI," "nonobstructive," "angiography," and "prognosis" were searched in PubMed and Embase databases from inception to December 2018, including original, English language MINOCA studies with >100 consecutive patients. Publications with a heterogeneous cohort, unreported coronary stenosis, or exclusively focusing on MINOCA-mimicking conditions, were excluded. Unpublished data were obtained from the MINOCA Global Collaboration. Data were pooled and analyzed using Paule-Mandel, Hartung, Knapp, Sidik & Jonkman, or restricted maximum-likelihood random-effects meta-analysis methodology. Heterogeneity was assessed using Cochran's Q and I2 statistics. The primary outcome was 12-month all-cause mortality in patients with MINOCA, with secondary comparisons to MI-CAD and No-MI. RESULTS: The 23 eligible studies yielded 55 369 suspected MINOCA, 485 382 MI-CAD, and 33 074 No-MI. Pooled meta-analysis of 14 MINOCA studies accounting for 30 733 patients revealed an unadjusted 12-month all-cause mortality rate of 3.4% (95% CI, 2.6%-4.2%) and reinfarction (n=27 605; 10 studies) in 2.6% (95% CI, 1.7%-3.5%). MINOCA had a lower 12-month all-cause mortality than those with MI-CAD (3.3% [95% CI, 2.5%-4.1%] versus 5.6% [95% CI, 4.1%-7.0%]; odds ratio, 0.60 [95% CI, 0.52-0.70], P<0.001). In contrast, there was a statistically nonsignificant trend towards increased 12-month all-cause mortality in patients with MINOCA (2.6% [95% CI, 0%-5.9%]) compared with No-MI (0.7% [95% CI, 0.1%-1.3%]; odds ratio, 3.71 [95% CI, 0.58-23.61], P=0.09). CONCLUSIONS: In the largest contemporary MINOCA meta-analysis to date, patients with suspected MINOCA had a favorable prognosis compared with MI-CAD, but statistically nonsignificant trend toward worse outcomes compared to those with No-MI. Registration: URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42020145356.

Randomized Evaluation of Beta Blocker and ACE-Inhibitor/Angiotensin Receptor Blocker Treatment for Post Infarct Angina in Patients With Myocardial Infarction With Non-obstructive Coronary Arteries: A MINOCA-BAT Sub Study Rationale and Design.

Introduction: Myocardial infarction with non-obstructive coronary arteries (MINOCA) occurs in ~10% of all patients with acute myocardial infarction (AMI), with an over-representation amongst women. Remarkably, it is estimated that as many as 1 in 4 patients with MINOCA experience ongoing angina at 12 months despite having no flow-restricting stenoses in their epicardial arteries. This manuscript presents the rationale behind Randomized Evaluation of Beta Blocker and Angiotensin-converting enzyme inhibitors/Angiotensin Receptor Blocker Treatment (ACEI/ARB) for Post Infarct Angina in MINOCA patients-The MINOCA BAT post infarct angina sub study. Methods: This trial is a registry-based, randomized, parallel, open-label, multicenter trial with 2 × 2 factorial design. The primary aim is to determine whether oral beta blockade compared with no oral beta blockade, and ACEI/ARB compared with no ACEI/ARB, reduce post infarct angina in patients discharged after MINOCA without clinical signs of heart failure and with left ventricular ejection fraction ≥40%. A total of 664 patients will be randomized into four groups; (i) ACEI/ARB with beta blocker, (ii) beta blocker only, (iii) ACEI/ARB only, or (iv) neither ACEI/ARB nor beta blocker and followed for 12 months. Results: The trial is currently recruiting in Australia and Sweden. Fifty six patients have been recruited thus far. Both sexes were equally distributed (52% women and 48% men) and the mean age was 56.3 ± 9.9 years. Conclusions: It remains unclear whether conventional secondary preventive therapies are beneficial to MINOCA patients in regard to post infarct angina. Existing registry-based literature suggest cardioprotective agents are less likely to be used in MINOCA patients. Thus, results from this trial will provide insights for future treatment strategies and guidelines specific to MINOCA patients.

Clinical and prognostic implications of C-reactive protein levels in myocardial infarction with nonobstructive coronary arteries.

BACKGROUND: Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a heterogeneous condition. Recent studies suggest that MINOCA patients may have a proinflammatory disposition. The role of inflammation in MINOCA may thus be distinct to myocardial infarction with significant coronary artery disease (MI-CAD). HYPOTHESIS: We hypothesized that inflammation reflected by C-reactive protein (CRP) levels might carry unique clinical information in MINOCA. METHODS: This retrospective registry-based cohort study (SWEDEHEART) included 9916 patients with MINOCA and 97 970 MI-CAD patients, used for comparisons. Multivariable-adjusted regressions were applied to investigate the associations of CRP levels with clinical variables, all-cause mortality and major cardiovascular events (MACE) during a median follow-up of up to 5.3 years. RESULTS: Median admission CRP levels in patients with MINOCA and MI-CAD were 5.0 (interquartile range 2.0-9.0) mg/dl and 5.0 (interquartile range 2.1-10.0 mg/dl), respectively. CRP levels in MINOCA exhibited independent associations with various cardiovascular risk factors, comorbidities and estimates of myocardial damage. The association of CRP with peripheral artery disease tended to be stronger compared to MI-CAD. The associations with female sex, renal dysfunction and myocardial damage were stronger in MI-CAD. CRP independently predicted all-cause mortality in MINOCA (hazard ratio 1.22 [95% confidence interval 1.17-1.26]), similar to MI-CAD (p interaction = 0.904). CRP also predicted MACE (hazard ratio 1.08 [95% confidence interval 1.04-1.12]) but this association was weaker compared to MI-CAD (p interaction<.001). CONCLUSIONS: We found no evidence indicating the presence of a specific inflammatory pattern in acute MINOCA compared to MI-CAD. However, CRP levels were independently, albeit moderately associated with adverse outcome.

Randomized evaluation of beta blocker and ACE-inhibitor/angiotensin receptor blocker treatment in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA-BAT): Rationale and design.

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is common and occurs in 6-8% of all patients fulfilling the diagnostic criteria for acute myocardial infarction (AMI). This paper describes the rationale behind the trial 'Randomized Evaluation of Beta Blocker and ACE-Inhibitor/Angiotensin Receptor Blocker Treatment (ACEI/ARB) of MINOCA patients' (MINOCA-BAT) and the need to improve the secondary preventive treatment of MINOCA patients. METHODS: MINOCA-BAT is a registry-based, randomized, parallel, open-label, multicenter trial with 2:2 factorial design. The primary aim is to determine whether oral beta blockade compared with no oral beta blockade, and ACEI/ARB compared with no ACEI/ARB, reduce the composite endpoint of death of any cause, readmission because of AMI, ischemic stroke or heart failure in patients discharged after MINOCA without clinical signs of heart failure and with left ventricular ejection fraction ≥40%. A total of 3500 patients will be randomized into four groups; e.g. ACEI/ARB and beta blocker, beta blocker only, ACEI/ARB only and neither ACEI/ARB nor beta blocker, and followed for a mean of 4 years. SUMMARY: While patients with MINOCA have an increased risk of serious cardiovascular events and death, whether conventional secondary preventive therapies are beneficial has not been assessed in randomized trials. There is a limited basis for guideline recommendations in MINOCA. Furthermore, studies of routine clinical practice suggest that use of secondary prevention therapies in MINOCA varies considerably. Thus results from this trial may influence future treatment strategies and guidelines specific to MINOCA patients.

Circadian onset and prognosis of myocardial infarction with non-obstructive coronary arteries (MINOCA).

BACKGROUND: Many acute cardiovascular events such as myocardial infarction (MI) follow circadian rhythms. Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a newly noticed entity with limited data on onset pattern and its impact on prognosis. MATERIAL AND METHODS: In this observational study of Swedish MINOCA patients registered in the SWEDEHEART registry between 2003-2013 and followed until December 2013 we identified 9,092 unique patients with MINOCA out of 199,163 MI admissions in total. Incidence rate ratios (IRR) were calculated for whole hours, parts of the day, weekdays, months, seasons and major holidays. RESULTS: The mean age was 65.5 years, 62.0% were women and 16.6% presented with STEMI. The risk for MINOCA proved to be most common in the morning (IRR = 1.70, 95% CI [1.63-1.84]) with a peak at 08.00 AM (IRR = 2.25, 95% CI [1.96-2.59]) and on Mondays (IRR = 1.28, 95% CI [1.18-1.38]). No altered risk was detected during the different seasons, the Christmas and New Year holidays or the Swedish Midsummer festivities. There was no association between time of onset of MINOCA and short- or long-term prognosis. CONCLUSION: The onset of MINOCA shows a circadian and circaseptan variation with increased risk at early mornings and Mondays, similar to previous studies on all MI, suggesting stress related triggering. However, during holidays were traditional MI increase, we did not see any increase for MINOCA. No association was detected between time of onset and prognosis, indicating that the underlying pathological mechanisms of MINOCA and the quality of care are similar at different times of onset but triggering mechanism may be more active early mornings and Mondays.

Reinfarction in Patients with Myocardial Infarction with Nonobstructive Coronary Arteries (MINOCA): Coronary Findings and Prognosis.

BACKGROUND: Myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA) is common. There are limited data on the mechanisms and prognosis for reinfarction in MINOCA patients. METHODS: In this observational study of MINOCA patients hospitalized in Sweden and registered in the SWEDEHEART registry between July 2003 and June 2013 and followed until December 2013, we identified 9092 unique patients with MINOCA of 199,163 MI admissions in total. The 570 (6.3%) MINOCA patients who were hospitalized due to a recurrent MI constituted the study group. RESULTS: The mean age was 69.1 years and 59.1% were women. The median time to readmission was 17 months. A total of 340 patients underwent a new coronary angiography and 180 (53%) had no obstructive coronary artery disease (CAD) and 160 (47%) had obstructive CAD; 123 had 1-vessel, 26 had 2-vessel, 9 had 3-vessel disease, and 2 had left main together with 1-vessel disease. Male sex, diabetes, peripheral vascular disease, higher levels of creatinine, and ST elevation at presentation were more common in patients with MI with obstructive CAD than in patients with a recurrent MINOCA. Mortality during a median follow-up of 38 months was similar whether the reinfarction event was MINOCA or MI with obstructive CAD 13.9% vs 11.9% (P = .54). CONCLUSIONS: About half of patients with reinfarction after MINOCA who underwent coronary angiography had progression of coronary stenosis. Angiography should be strongly considered in patients with MI after MINOCA. Mortality associated with recurrent events was substantial, though there was no difference in mortality between those with or without significant CAD.

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.

Unrecognized Myocardial Infarction Assessed by Cardiac Magnetic Resonance Imaging--Prognostic Implications.

BACKGROUND: Clinically unrecognized myocardial infarctions (UMI) are not uncommon and may be associated with adverse outcome. The aims of this study were to determine the prognostic implication of UMI in patients with stable suspected coronary artery disease (CAD) and to investigate the associations of UMI with the presence of CAD. METHODS AND FINDINGS: In total 235 patients late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) imaging and coronary angiography were performed. For each patient with UMI, the stenosis grade of the coronary branch supplying the infarcted area was determined. UMIs were present in 25% of the patients and 67% of the UMIs were located in an area supplied by a coronary artery with a stenosis grade ≥70%. In an age- and gender-adjusted model, UMI independently predicted the primary endpoint (composite of death, myocardial infarction, resuscitated cardiac arrest, hospitalization for unstable angina pectoris or heart failure within 2 years of follow-up) with an odds ratio of 2.9; 95% confidence interval 1.1-7.9. However, this association was abrogated after adjustment for age and presence of significant coronary disease. There was no difference in the primary endpoint rates between UMI patients with or without a significant stenosis in the corresponding coronary artery. CONCLUSIONS: The presence of UMI was associated with a threefold increased risk of adverse events during follow up. However, the difference was no longer statistically significant after adjustments for age and severity of CAD. Thus, the results do not support that patients with suspicion of CAD should be routinely investigated by LGE-CMR for UMI. However, coronary angiography should be considered in patients with UMI detected by LGE-CMR. TRIAL REGISTRATION: ClinicalTrials.gov NTC01257282.

Unrecognized myocardial infarctions detected by cardiac magnetic resonance imaging are associated with cardiac troponin I levels.

BACKGROUND: Both unrecognized myocardial infarction (UMI) and elevated levels of biomarkers are common in patients with stable coronary artery disease (CAD). The objective of this study was to determine the association between levels of cardiac biomarkers, UMI and extent of CAD in patients with stable CAD. METHODS: A total of 235 patients (median age: 65years; 34% women) with stable CAD without previously known myocardial infarction were examined with late gadolinium enhancement cardiovascular magnetic resonance imaging and coronary angiography. Blood samples were drawn at enrolment and high sensitivity cardiac troponin I (cTnI), NT-proBNP and Galectin-3 were analyzed. RESULTS: UMI was detected in 58 patients (25%). The median levels of cTnI, NT-proBNP and Galectin-3 were significantly higher in patients with UMI compared to those without, (p<0.001, p=0.006 and p=0.033, respectively). After adjustment for cardiovascular risk factors, left ventricular ejection fraction and renal function, cTnI remained independently associated with the presence of UMI (p=0.031) and the extent of CAD (p=0.047). Neither NT-proBNP, nor Galectin-3, was independently associated with UMI or extent of CAD. CONCLUSIONS: The independent association between levels of cTnI and UMI indicates a common pathophysiological pathway for the cTnI elevation and development of UMI. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT01257282).

Unrecognized myocardial infarctions assessed by cardiovascular magnetic resonance are associated with the severity of the stenosis in the supplying coronary artery.

BACKGROUND: A previous study has shown an increased prevalence of late gadolinium enhancement cardiovascular magnetic resonance (LGE CMR) detected unrecognized myocardial infarction (UMI) with increasing extent and severity of coronary artery disease. However, the coronary artery disease was evaluated on a patient level assuming normal coronary anatomy. Therefore, the aims of the present study were to investigate the prevalence of UMI identified by LGE CMR imaging in patients with stable angina pectoris and no known previous myocardial infarction; and to investigate whether presence of UMI is associated with stenotic lesions in the coronary artery supplying the segment of the myocardium in which the UMI is located, using coronary angiography to determine the individual coronary anatomy in each patient. METHODS: In this prospective multicenter study, we included patients with stable angina pectoris and without prior myocardial infarction, scheduled for coronary angiography. A LGE CMR examination was performed prior to the coronary angiography. The study cohort consisted of 235 patients (80 women, 155 men) with a mean age of 64.8 years. RESULTS: UMIs were found in 25% of patients. There was a strong association between stenotic lesions (≥70% stenosis) in a coronary artery and the presence of an UMI in the myocardial segments supplied by the stenotic artery; it was significantly more likely to have an UMI downstream a stenosis ≥ 70% as compared to < 70% (OR 5.1, CI 3.1-8.3, p < 0.0001). 56% of the UMIs were located in the inferior and infero-lateral myocardial segments, despite predominance for stenotic lesions in the left anterior descending artery. CONCLUSION: UMI is common in patients with stable angina and the results indicate that the majority of the UMIs are of ischemic origin due to severe coronary atherosclerosis. In contrast to what is seen in recognized myocardial infarctions, UMIs are predominately located in the inferior and infero-lateral myocardial segments. TRIAL REGISTRATION: The PUMI study is registered at ClinicalTrials.gov (NCT01257282).

Short- and long-term individual variation in NT-proBNP levels in patients with stable coronary artery disease.

BACKGROUND: In addition to diagnosis of heart failure (HF) natriuretic peptides (BNP and NT-proBNP) may be used for risk prediction in stable and acute coronary artery disease. The aim of the study was to evaluate the short- and long-term individual variation of NT-proBNP in patients with stable coronary artery disease. METHODS: Twenty-four patients with suspected stable coronary artery disease and scheduled for elective coronary angiography were included. Blood samples were drawn at enrolment and, on average 3 weeks later, serially the day prior to coronary angiography. NT-proBNP was determined using Elecsys proBNP sandwich immunoassay (Roche Diagnostics). RESULTS: The individual variation in NT-proBNP over 4h was 11.8%, over 20 h 12.4% and over 3 weeks 20.4%. The corresponding positive and negative lognormal reference change values (RCV) were +41/-29%, +42/-30% and +76/-43%, respectively. No significant circadian variation was found. CONCLUSIONS: Our results suggest that an increase in NT-proBNP levels of >42% or a decrease of >30% is needed to indicate a reliable short-term change; and for a long-term change an increase of >76% or a decrease of >43% is required. This should be considered when interpreting changes in NT-proBNP levels.

Short- and long-term individual variation in cardiac troponin in patients with stable coronary artery disease.

BACKGROUND: A rise or fall of cardiac troponin is a prerequisite for the diagnosis of acute myocardial infarction. Defining significant changes requires knowledge of both biological and analytical variation. The short-term biological variation of cardiac troponin in healthy individuals is 3%-48%. However, healthy individuals may not be representative for patients in whom cardiac troponin measurement is often of clinical importance. Therefore, we studied the individual variation of cardiac troponin in patients with symptoms of stable coronary artery disease. METHODS: Twenty-four patients scheduled for elective coronary angiography were included. Blood samples were drawn once at enrollment and serially at six 4-h intervals on the day before coronary angiography. Cardiac troponin was measured with hs-cTn assays from Abbott Laboratories (premarket cTnI assay) and Roche Diagnostics (Elecsys(®) cTnT assay with two different lots). RESULTS: The short-term individual variation in cardiac troponin I (cTnI) was 14%, the reference change value (RCV) 49%, and RCV-log-normal (rise/fall) 54%/-35%. The corresponding values for cTnT were 7%, 23%, and 26%/-21%. The long-term variation for cTnI was 24%, RCV 69%, and RCV-log-normal (rise/fall) 97%/-49%. The corresponding values for cTnT were 11%, 32%, and 37%/-27%. CONCLUSIONS: The short-term individual variation of cardiac troponin in patients with symptoms of stable coronary artery disease is similar to the biological variation previously demonstrated in healthy individuals. Our results suggest that a change in cardiac troponin concentrations of >50% can be used in attempting to diagnose acute myocardial injury. To detect significant long-term changes in cardiac troponin concentrations, larger changes will be required.