Acute myocardial infarction: initial manifestations, management, and prognosis

LINC00936 exacerbated myocardial infarction progression via miR-4795-3p/Wnt3a signaling pathway based on biological and imaging methods

OBJECTIVE

LncRNAs show great potential in diagnosing and treating myocardial infarction (MI). Clarifying the mechanism of lncRNAs on MI is of great significance for the application of MI biomarkers. Therefore, this report intended to determine the role and mechanism of LINC00936 on MI by biological and imaging methods.

METHODS

Hypoxia H9C2 model was established by hypoxia treatment. Flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling assay detected the apoptosis of H9C2. H2DCFDA staining and enzyme-linked immunosorbent assay (ELISA) was used to detect the reactive oxygen species (ROS) accumulation and Lactate dehydrogenase (LDH) contents, respectively. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect LINC00936, Wnt3a and miR-4795-3p levels. Western blot detected Wnt3a protein expression. Dual luciferase reporter assays detected the relationship of miR-4795-3p to LINC00936 or Wnt3a. Echocardiography analysis detected cardiac function. 2,3,5-Triphenyltetrazolium chloride (TTC) detected the infarct size. Masson staining detected the pathological changes.

RESULTS

LINC00936 level was elevated in the MI patients compared with the controls. Overexpression of LINC00936 promoted apoptosis and ROS accumulation in hypoxia H9C2 model and exacerbated MI progression in vivo. miR-4795-3p bound with LINC00936 in H9C2 cells and miR-4795-3p mimics inhibited apoptosis and ROS accumulation in hypoxia H9C2 model regulated by LINC00936. Wnt3a was targeted by miR-4795-3p and Wnt3a elevation promoted apoptosis and ROS accumulation in hypoxia H9C2 model.

CONCLUSION

In this report, we illustrated that LINC00936 exacerbated MI progression via the miR-4795-3p/Wnt3a signaling pathway based on biological and imaging methods. These findings might provide potential molecular target for the diagnosis and treatment of MI.

Late survival after perioperative myocardial infarction complicating vascular surgery

PURPOSE

Although early death from perioperative myocardial infarction (PMI) after vascular surgery is well established, long-term outcome in patients surviving PMI is unknown. This prospective study was designed to determine cardiac outcome and survival rates in patients with symptomatic and asymptomatic nonfatal PMI associated with peripheral vascular surgery.

METHODS

During a 36-month period for 1989 to 1992, all patients undergoing vascular surgery at our institution were monitored for PMI with serial creatine kinase and myocardial band isoenzymes and electrocardiography. PMIs were classified as symptomatic (associated with chest pain, arrhythmia, congestive heart failure, or hypotension) or asymptomatic (electrocardiographic changes and/or elevated creatine kinase and myocardial band isoenzymes). Patients with PMI were then prospectively monitored and compared for late survival, with control patients undergoing vascular surgery without PMI during the same interval.

RESULTS

During the study period 1561 major peripheral vascular procedures were performed. There were 47 PMIs (3.0%). Eleven (0.7%) PMIs were fatal, 31 were nonfatal, and five other patients with PMI died during operation of non-heart-related causes. Eight of 31 patients with nonfatal PMI had a "chemical PMI" with creatine kinase and myocardial band isoenzyme elevation as the sole indicator of PMI. During follow-up (mean 27.7 months), there was a higher incidence of both subsequent myocardial infarction and coronary artery revascularization among the patients with nonfatal PMI compared with control subjects (p < 0.05); however, survival for patients with nonfatal PMI at 1 and 4 years (80% and 51%) did not differ from that of control patients (90% and 60%) (p > 0.05). Patients with "chemical PMI" had similar patterns of subsequent myocardial infarction and coronary intervention as control patients.

CONCLUSIONS

Patients surviving nonfatal PMI after peripheral vascular surgery have a higher incidence of subsequent adverse cardiac events and coronary artery revascularization than patients undergoing vascular surgery without PMI, but they have similar survival rates at 1 and 4 years. Patients in the enzyme-only PMI group have a similar outcome compared with control subjects suggesting that a perioperative "chemical MI" may not be a significant clinical event.

Determinants of the prognosis after a first myocardial infarction in a migrant Japanese population. The Honolulu Heart Program

BACKGROUND

Although numerous studies have been published on the prognostic assessment of myocardial infarction, little is known about determinants of the prognosis after a first myocardial infarction, especially regarding the role of standard risk factors for coronary heart disease (CHD) measured before the development of myocardial infarction.

METHODS AND RESULTS

In a prospective study of CHD among men of Japanese ancestry living in Hawaii, 457 patients with a first myocardial infarction (age range, 46 to 84 years) were identified during 20 years of follow-up. The relations of clinical variables and CHD risk factors to mortality in early (< 30 days) and two stages of late (30 days to 5 years and 5 to 10 years) periods after myocardial infarction in these patients were investigated. In multivariate analyses using logistic regression models (for early mortality) and Cox regression models (for late mortality), age at myocardial infarction and severe complications (Killip classes 3 and 4) were independent predictors of both early and late mortality (up to 5 years after myocardial infarction). In addition, ventricular arrhythmias predicted only early mortality, whereas anterior myocardial infarction, radiological evidence of cardiomegaly and/or pulmonary congestion, and intraventricular block predicted only late mortality (up to 5 years after myocardial infarction). Only age was an independent predictor of all-cause mortality more than 5 years after myocardial infarction. After adjusting for age at myocardial infarction and these clinical variables, preinfarction-measured risk factors such as 1-hour postload serum glucose (positively) and 1-second forced expiratory volume (inversely) were significantly associated with late mortality up to 5 years, whereas systolic blood pressure was the only independent predictor of late mortality after 5 years.

CONCLUSIONS

This study has confirmed the importance of age at myocardial infarction and clinical indicators of complications such as Killip class 3 or 4, radiological evidence of pulmonary congestion, and ventricular arrhythmias or intraventricular block as the prognostic determinants of myocardial infarction. In addition, some of the preinfarction-measured standard risk factors for CHD were found to predict long-term prognosis independent of age and clinical factors.

How much testing is needed after myocardial infarction?

Both physicians and patients should be encouraged by the tremendous progress made in the clinical care of patients with heart disease during the last 20 years. However, the number of invasive and noninvasive tests is vast, so they need to be applied judiciously, using a reasonable set of clinical principles to recognize the needs of the individual patient. In the case of myocardial infarction, one of the most important prognostic factors is left ventricular systolic function, which is commonly measured by the ejection fraction. This measurement can be made with a left ventriculogram, radionuclide ventriculogram, or two-dimensional echocardiogram, the choice depending on individual circumstances.

Mechanical and electrical complications of acute myocardial infarction

Although much of the current enthusiasm in the management of acute myocardial infarction is related to revascularization strategies, mechanical and electrical complications continue to pose a major threat to recovery in some patients. Some of the major complications of acute myocardial infarction are cardiogenic shock, rupture of the free wall and pseudoaneurysm, rupture of the ventricular septum, acute mitral regurgitation, right ventricular myocardial infarction, infarct expansion or extension, pericarditis and tamponade, peri-infarction hypertension, and tachyarrhythmias and bradyarrhythmias. For each of these complications, general guidelines for diagnosis and management are offered. Early, aggressive, and judicious treatment of these complications may substantially decrease the morbidity and mortality associated with acute myocardial infarction.