Project description:It is assumed that platelets in diseased conditions share similar properties to platelets in healthy conditions, although this has never been examined in detail for myocardial infarction (MI). We examined platelets from patients with ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) compared with platelets from healthy volunteers to evaluate for differences in platelet phenotype and function. Platelet activation was examined and postreceptor signal transduction pathways were assessed. Platelet-derived plasma biomarkers were evaluated by receiver operator characteristic curve analysis. Maximum platelet activation through the thromboxane receptor was greater in STEMI than in NSTEMI but less through protease-activated receptor 1. Extracellular-signal related-kinase 5 activation, which can activate platelets, was increased in platelets from subjects with STEMI and especially in platelets from patients with NSTEMI. Matrix metalloproteinase 9 (MMP9) protein content and enzymatic activity were several-fold greater in platelets with MI than in control. Mean plasma MMP9 concentration in patients with MI distinguished between STEMI and NSTEMI (area under curve [AUC] 75% [confidence interval (CI) 60-91], P?=?0.006) which was superior to troponin T (AUC 66% [CI 48-85, P?=?0.08), predicting STEMI with 80% sensitivity (95% CI 56-94), 90% specificity (CI 68-99), 70% AUC (CI 54-86, P?<?0.0001), and NSTEMI with 50% sensitivity (CI 27-70), 90% specificity (CI 68-99), 70% AUC (CI 54-86, P?=?0.03). Platelets from patients with STEMI and NSTEMI show differences in platelet surface receptor activation and postreceptor signal transduction, suggesting the healthy platelet phenotype in which antiplatelet agents are often evaluated in preclinical studies is different from platelets in patients with MI.
Project description:ObjectiveTo investigate the relationship between ST-segment resolution (STR) and myocardial scar thickness after percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI).MethodsForty-two STEMI patients with single-branch coronary artery stenosis or occlusion were enrolled. ST-segment elevations were measured at emergency admission and at 24 h after PCI. Late gadolinium-enhanced cardiac magnetic resonance imaging (CMR-LGE) was performed 7 days after PCI to evaluate myocardial scars. Statistical analyses were performed to assess the utility of STR to predict the development of transmural (> 75%) or non-transmural (< 75%) myocardial scars, according to previous study.ResultsThe sensitivity and specificity of STR for predicting transmural scars were 96% and 88%, respectively, at an STR cut-off value of 40.15%. The area under the curve was 0.925. Multivariate logistic proportional hazards regression analysis disclosed that patients with STR < 40.15% had a 170.90-fold higher probability of developing transmural scars compared with patients with STR ≥ 40.15%. Pearson correlation and linear regression analyses showed STR percentage was significantly associated with myocardial scar thickness and size.ConclusionSTR < 40.15% at 24 h after PCI may provide meaningful diagnostic information regarding the extent of myocardial scarification in STEMI patients.
Project description:ImportanceChallenges to improving ST-segment elevation myocardial infarction (STEMI) care are formidable in low- to middle-income countries because of several system-level factors.ObjectiveTo examine access to reperfusion and percutaneous coronary intervention (PCI) during STEMI using a hub-and-spoke model.Design, setting, and participantsThis multicenter, prospective, observational study of a quality improvement program studied 2420 patients 20 years or older with symptoms or signs consistent with STEMI at primary care clinics, small hospitals, and PCI hospitals in the southern state of Tamil Nadu in India. Data were collected from the 4 clusters before implementation of the program (preimplementation data). We required a minimum of 12 weeks for the preimplementation data with the period extending from August 7, 2012, through January 5, 2013. The program was then implemented in a sequential manner across the 4 clusters, and data were collected in the same manner (postimplementation data) from June 12, 2013, through June 24, 2014, for a mean 32-week period.ExposuresCreation of an integrated, regional quality improvement program that linked the 35 spoke health care centers to the 4 large PCI hub hospitals and leveraged recent developments in public health insurance schemes, emergency medical services, and health information technology.Main outcomes and measuresPrimary outcomes focused on the proportion of patients undergoing reperfusion, timely reperfusion, and postfibrinolysis angiography and PCI. Secondary outcomes were in-hospital and 1-year mortality.ResultsA total of 2420 patients with STEMI (2034 men [84.0%] and 386 women [16.0%]; mean [SD] age, 54.7 [12.2] years) (898 in the preimplementation phase and 1522 in the postimplementation phase) were enrolled, with 1053 patients (43.5%) from the spoke health care centers. Missing data were common for systolic blood pressure (213 [8.8%]), heart rate (223 [9.2%]), and anterior MI location (279 [11.5%]). Overall reperfusion use and times to reperfusion were similar (795 [88.5%] vs 1372 [90.1%]; P = .21). Coronary angiography (314 [35.0%] vs 925 [60.8%]; P < .001) and PCI (265 [29.5%] vs 707 [46.5%]; P < .001) were more commonly performed during the postimplementation phase. In-hospital mortality was not different (52 [5.8%] vs 85 [5.6%]; P = .83), but 1-year mortality was lower in the postimplementation phase (134 [17.6%] vs 179 [14.2%]; P = .04), and this difference remained consistent after multivariable adjustment (adjusted odds ratio, 0.76; 95% CI, 0.58-0.98; P = .04).Conclusions and relevanceA hub-and-spoke model in South India improved STEMI care through greater use of PCI and may improve 1-year mortality. This model may serve as an example for developing STEMI systems of care in other low- to middle-income countries.
Project description:Infarction of the anterior myocardial wall results in anterior ST-elevation. However, ST-deviation may also appear inferiorly and may aid in localizing the culprit lesion.
Project description:Recent studies have proposed intravenous (IV) morphine is associated with delayed action of antiplatelet agents in acute myocardial infarction. However, it is unknown whether morphine results in increased myocardial damage in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI). We investigated myocardial salvage index (MSI) to determine whether IV morphine affects myocardial injury adversely in STEMI patients undergoing primary PCI. 299 STEMI patients underwent contrast-enhanced magnetic resonance imaging a median of 3 days after PCI. Infarct size was measured on delayed-enhancement imaging, and area at risk was quantified on T2-weighted imaging. MSI was calculated as '[area at risk-infarct size] X 100 / area at risk'. IV morphine was administrated in 32.1% of patients. Patients treated with morphine had shorter symptom to balloon time and higher prevalence of Thrombolysis in Myocardial Infarction flow grade 0 or 1. The morphine group showed a trend toward larger MSI and infarct size and significantly greater area at risk than the non-morphine group. After propensity score matching (90 pairs), MSI was similar between the morphine and non-morphine group (46.1% versus 43.5%, P = .11), and infarct size and area at risk showed no difference. In propensity score-matched analysis, IV morphine prior to primary PCI in STEMI patients did not cause adverse impacts on myocardial salvage.
Project description:ST segment elevation myocardial infarction remains a significant contributor to morbidity and mortality worldwide, despite a declining incidence and better survival rates. It usually results from thrombotic occlusion of a coronary artery at the site of a ruptured or eroded plaque. Diagnosis is based on characteristic symptoms and electrocardiogram changes, and confirmed subsequently by raised cardiac enzymes. Prognosis is dependent on the size of the infarct, presence of collaterals and speed with which the occluded artery is reopened. Mechanical reperfusion by primary percutaneous coronary intervention is superior to fibrinolytic therapy if delivered by an experienced team in a timely fashion. Post-reperfusion care includes monitoring for complications, evaluation of left ventricular function, secondary preventive therapy and cardiac rehabilitation.
Project description:California has led successful regionalized efforts for several time-critical medical conditions, including ST-segment elevation myocardial infarction (STEMI), but no specific mandated protocols exist to define regionalization of care. We aimed to study the trends in regionalization of care for STEMI patients in the state of California and to examine the differences in patient demographic, hospital, and county trends.Using survey responses collected from all California emergency medical services (EMS) agencies, we developed four categories - no, partial, substantial, and complete regionalization - to capture prehospital and inter-hospital components of regionalization in each EMS agency's jurisdiction between 2005-2014. We linked the survey responses to 2006 California non-public hospital discharge data to study the patient distribution at baseline.STEMI regionalization-of-care networks steadily developed across California. Only 14% of counties were regionalized in 2006, accounting for 42% of California's STEMI patient population, but over half of these counties, representing 86% of California's STEMI patient population, reached complete regionalization in 2014. We did not find any dramatic differences in underlying patient characteristics based on regionalization status; however, differences in hospital characteristics were relatively substantial.Potential barriers to achieving regionalization included competition, hospital ownership, population density, and financial challenges. Minimal differences in patient characteristics can establish that patient differences unlikely played any role in influencing earlier or later regionalization and can provide a framework for future analyses evaluating the impact of regionalization on patient outcomes.
Project description:BackgroundUnder conditions of oxidative stress, hydroxyl radicals can oxidize phenylalanine (Phe) into various tyrosine (Tyr) isomers (meta-, ortho-, and para-tyrosine; m-, o-, and p-Tyr), depending on the location of the hydroxyl group on the oxidized benzyl ring. This study aimed to compare patients with ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) and the serum levels of Phe and Tyr isomers at the aortic root and distal to the culprit lesion in both groups.MethodsForty-four patients participated in the study: 23 with STEMI and 21 with NSTEMI. Arterial blood samples were taken from the aortic root through a guiding catheter and from the culprit vessel segment distal from the primary lesion with an aspiration catheter, during the percutaneous coronary intervention. Serum levels of Phe, p-Tyr, m-Tyr, and o-Tyr were determined using reverse-phase high-performance liquid chromatography.ResultsSerum levels of Phe were significantly higher distal to the culprit lesion compared to the aortic root in patients with STEMI. Serum p-Tyr/Phe and m-Tyr/Phe concentration ratios were both lower distal to the culprit lesion than at the aortic root in patients with STEMI. There were no statistically significant differences with respect to changes in serum Phe and Tyr isomers distal to the culprit lesion compared to the aortic root in patients with NSTEMI.ConclusionOur data suggest that changes in serum levels of different Tyr isomers can mediate the effects of oxidative stress during myocardial infarction.
Project description:The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), that causes coronavirus disease 2019 (COVID-19), has resulted in a global pandemic. Patients with cardiovascular risk factors or established cardiovascular disease are more likely to experience severe or critical COVID-19 illness and myocardial injury is a key extra-pulmonary manifestation. These patients frequently present with ST-elevation on an electrocardiogram (ECG) due to multiple etiologies including obstructive, non-obstructive, and/or angiographically normal coronary arteries. The incidence of ST-elevation myocardial infarction (STEMI) mimics in COVID-19-positive hospitalized patients, and the association with morbidity and mortality is unknown. Understanding the natural history and appropriate management of COVID-19 patients presenting with ST elevation is essential to inform patient management decisions and protect healthcare workers. Methods:The Society for Cardiovascular Angiography and Interventions (SCAI) and The Canadian Association of Interventional Cardiology (CAIC) in conjunction with the American College of Cardiology Interventional Council have collaborated to create a multi-center observational registry, NACMI. This registry will enroll confirmed COVID-19 patients and persons under investigation (PUI) with new ST-segment elevation or new onset left bundle branch block (LBBB) on the ECG with clinical suspicion of myocardial ischemia. We will compare demographics, clinical findings, outcomes and management of these patients with a historical control group of over 15,000 consecutive STEMI activation patients from the Midwest STEMI Consortium using propensity matching. The primary clinical outcome will be in- hospital major adverse cardiovascular events (MACE) defined as composite of all-cause mortality, stroke, recurrent MI, and repeat unplanned revascularization in COVID-19 confirmed or PUI. Secondary outcomes will include the following: reporting of etiologies of ST Elevation; cardiovascular mortality due to myocardial infarction, cardiac arrest and /or shock; individual components of the primary outcome; composite primary outcome at 1 year; as well as ECG and angiographic characteristics. Conclusion:The multicenter NACMI registry will collect data regarding ST elevation on ECG in COVID-19 patients to determine the etiology and associated clinical outcomes. The collaboration and speed with which this registry has been created, refined, and promoted serves as a template for future research endeavors.
Project description:Primary PCI of infarct-related arteries is the preferred reperfusion strategy in patients presenting with ST-segment elevation myocardial infarction (STEMI). Up to 40 % of such patients demonstrate evidence of multivessel, non-infarct-related artery coronary disease. Previous non-randomised observational studies and their associated meta-analyses have suggested that in such cases only the culprit infarct-related artery (IRA) lesion should be treated. However, recent randomised controlled trials have demonstrated improved clinical outcomes with lower major adverse cardiovascular events (MACE) rates when complete revascularisation is undertaken either at index primary percutaneous coronary intervention (PPCI) or during index admission. These trials suggest that current guidelines pertaining to treatment of non-infarct-related artery (N-IRA) lesions in STEMI patients with multivessel disease may need to be reconsidered depending on future trials. However, issues remain around timing of N-IRA intervention, the use of fractional flow reserve (FFR) or intravascular imaging to guide intervention in N-IRA lesions and the need to demonstrate reductions in hard clinical endpoints (death and MI) after complete revascularisation; these issues will need to be addressed through future trials. Clinicians must judge on the currently available data, whether it is still safer to leave important stenosis in N-IRA untreated.