Management of patients after their first myocardial infarction

SCD leads to the development and progression of acute myocardial infarction through the AMPK signaling pathway

Background

Acute myocardial infarction (AMI) is myocardial necrosis caused by acute coronary ischemia and hypoxia. It can be complicated by arrhythmia, shock, heart failure and other symptoms that can be life-threatening. A multi-regulator driven dysfunction module for AMI was constructed. It is intended to explore the pathogenesis and functional pathways regulation of acute myocardial infarction.

Methods

Combining differential expression analysis, co-expression analysis, and the functional enrichment analysis, a set of expression disorder modules related to AMI was obtained. Hypergeometric test was performed to calculate the potential regulatory effects of multiple factors on the module, identifying a range of non-coding RNA and transcription factors.

Results

A total of 4551 differentially expressed genes for AMI and seven co-expression modules were obtained. These modules are primarily involved in the metabolic processes of prostaglandin transport processes, regulating DNA recombination and AMPK signal transduction. Based on this set of functional modules, 3 of 24 transcription factors (TFs) including NFKB1, MECP2 and SIRT1, and 3 of 782 non-coding RNA including miR-519D-3P, TUG1 and miR-93-5p were obtained. These core regulators are thought to be involved in the progression of AMI disease. Through the AMPK signal transduction, the critical gene stearoyl-CoA desaturase (SCD) can lead to the occurrence and development of AMI.

Conclusions

In this study, a dysfunction module was used to explore the pathogenesis of multifactorial mediated AMI and provided new methods and ideas for subsequent research. It helps researchers to have a deeper understanding of its potential pathogenesis. The conclusion provides a theoretical basis for biologists to design further experiments related to AMI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02011-8.

Cardiac decompensation during an ischemic event weakens the predictive power of myocardial injury markers

Our objection was to find determinants of long-term outcome in routine data collected for differential diagnosis of suspected acute myocardial infarction. Study population consisted of 263 discharged patients who were initially hospitalized for differential diagnosis of suspected acute myocardial infarction between October 1992 and January 1993. Follow-up time for all cause and cardiac mortality was 5 years. The variables studied as predictors of outcome were computerized ECG, peak creatine kinase isoenzyme MB, peak troponin I, radiographic evidence of pulmonary congestion (cardiac decompensation), treatment for hyperlipidemia, hypertension or diabetes, smoking, previous myocardial infarction, age and gender. Total mortality was 32% at 5 years, of which 77% (64/83) was of cardiac origin. Pulmonary congestion in chest X-ray was the most powerful predictor of outcome (RR=3.3, 95% CI=2.0-5.2, P<0.001). In multivariate analysis congestion (RR=3.3, CI=2.0-5.2) was the only independent predictor of 5-year total mortality in addition to age (RR=1.06, CI=1.04-1.08). These two variables together with previous myocardial infarction (RR=1.9, CI=1.2-3.1) and hyperlipidemia (RR=2. 0, CI=1.1-3.5) were independent predictors of cardiac mortality. Radiographic evidence of cardiac decompensation during hospitalization is a strong and independent predictor of long-term outcome in unselected patients with suspected AMI. The predictive power of cardiac markers is confined to patients without pulmonary congestion.

Successful implementation of guidelines for encouraging the use of beta blockers in patients after acute myocardial infarction

PURPOSE

To assess whether implementation of guidelines increases the prescription of drugs, particularly beta blockers, recommended for secondary prevention after acute myocardial infarction.

SUBJECTS AND METHODS

Prescription patterns among 355 patients discharged from a public teaching hospital after recovery from myocardial infarction were prospectively monitored in a before-after trial. The implementation strategies included educational interventions (large group meetings), placement of guidelines in patients' records, and bimonthly general reminders sent to physicians.

RESULTS

Beta blockers were prescribed in 93 (38%) of 243 survivors of acute myocardial infarction before guideline implementation (12-month control period), as compared with 71 (63%) of 112 patients (P <0.001) after their implementation (6-month period). During the entire study period, the prescription of beta blockers at a neighboring public teaching hospital, used as a comparison, was unchanged. After adjusting for potential confounders, implementation of the guidelines remained significantly associated with prescription of beta blockers at discharge [odds ratio (OR) = 10; 95% confidence interval (CI), 3.2 to 33; P <0.001]. Other independent predictors of prescription of beta blockers were previous coronary artery bypass grafting (OR = 8.7; 95% CI, 2.5 to 31; P = 0.001), hypertension (OR = 2.5; 95% CI, 1.4 to 4.5; P = 0.003), age per 10-year increase (OR = 0.82; 95% CI, 0.67 to 0.99; P = 0.04), secular trend in prescription patterns expressed in months (OR = 0.9; 95% CI, 0.8 to 1.0; P = 0.02), a left ventricular ejection fraction < or = 40% (OR = 0.2; 95% CI, 0.1 to 0.4; P <0.001), the presence of atrioventricular block (OR = 0.1; 95% CI, 0.02 to 0.7; P = 0.02), and concomitant prescription of digoxin (OR = 0.2; 95% CI, 0.05 to 0.8; P = 0.02) or calcium antagonists (OR = 0.06; 95% CI, 0.01 to 0.3; P = 0.001).

CONCLUSION

When appropriately developed and implemented by local experts, literature-based guidelines may be effective in modifying use of recommended drugs for secondary prevention of coronary artery disease, such as prescription of beta blockers.

Analytical and clinical evaluation of new diagnostic tests for myocardial damage

As with any new test, novel cardiac markers must meet basic analytical and clinical performance issues. For sensitivity and specificity, it is important to know what protein forms are released into blood after injury, and which of these forms are measured by the assays in question. When commercial tests become available, the choice of the measurement platform will be important in the timely delivery of results. The cut-off concentration used is also important, and requires careful selection of the patient groups to be studied. If the intent of the marker is to be used to diagnose acute myocardial infarction (AMI), data from normal subjects should not be included. However, low cut-off limits can be useful for detection of minor myocardial injury if the new assay is highly sensitive and specific. New tests are needed in the area of early diagnosis of AMI, detection of reinfarction or myocardial extension after AMI, risk stratification of patients with unstable angina, and therapeutic monitoring of patients with congestive heart failure. The most promising new markers are glycogen phosphorylase BB, free fatty acid binding protein, and brain natriuretic peptide.

The use of hormone replacement therapy in women with acute myocardial infarction: an audit of current practice

We undertook criterion-based audit of the current practice of prescribing hormone replacement therapy for women with acute myocardial infarction; the audit included 181 consecutive women admitted to one hospital with this diagnosis in one calendar year. The set standard was that, barring any contraindication, all postmenopausal women with acute myocardial infarction should be prescribed hormone replacement therapy before discharge from hospital. The evidence base of this standard derives from more than 30 epidemiological and clinical studies and a large body of biological data. Only 4.7% of the women were current users of hormone replacement therapy and the set standard was met in only 3% of eligible nonusers. Professionals caring for women who have had a myocardial infarction need to consider hormone replacement therapy as a secondary prophylaxis of myocardial infarction. Gynaecologists should liaise with colleagues in other specialties and general practice to ensure that information on the nongynaecological benefits of hormone replacement therapy is widely disseminated.

Nisoldipine coat-core. A review of its pharmacodynamic and pharmacokinetic properties and clinical efficacy in the management of ischaemic heart disease

Nisoldipine coat-core is an extended-release once-daily formulation of a dihydropyridine calcium antagonist effective in the treatment of chronic stable angina pectoris. With immediate-release formulations of nisoldipine, plasma drug concentrations that produce therapeutic effects result rapidly, but are not sustained and do not maintain the effects throughout a 12-hour dosage interval. In contrast, with nisoldipine coat-core, a gradual increase in plasma nisoldipine concentrations occurs over 12 hours and therapeutic concentrations are then maintained for the duration of a 24-hour dosage interval. In dosages of 10 to 60 mg once daily, nisoldipine coat-core controls symptoms of angina and improves exercise-induced signs of ischaemia in patients with stable angina. Compared with placebo, daily nisoldipine coat-core doses of > or = 20 mg provide statistically significant increases in total exercise time and time to produce angina and a trend towards an increase in the time to produce 1 mm ST segment depression, in exercise tests conducted approximately 23 hours postdose. When administered in 20 and 40 mg daily doses, nisoldipine coat-core produces improvements in exercise test parameters that are similar to those seen with amlodipine 5 or 10 mg/day or regular-release or sustained-release (SR) diltiazem 240 mg/day. The frequency of daily angina attacks and consumption of short-acting nitrates are also reduced by nisoldipine to a similar extent to that observed with these other agents. After longer term (1 year) administration of 10 to 60 mg daily, improvements in exercise test parameters are maintained, with equivalent anti-ischaemic efficacy seen in patients receiving nisoldipine coat-core alone or with background nitrate or beta-blocker therapy. Adverse events associated with nisoldipine coat-core are typical of the dihydropyridine class of calcium antagonists, with peripheral oedema and headache being most common. Nisoldipine coat-core appears to be associated with fewer deaths than placebo, notably in the DEFIANT-II (Doppler Flow and Echocardiography in Functional Cardiac Insufficiency: Assessment of Nisoldipine Therapy II) study, where only 1 death occurred with nisoldipine compared with 7 in the placebo group. Nisoldipine should not be taken during phenytoin therapy. In addition, grapefruit juice should be avoided during nisoldipine therapy and nisoldipine should not be taken concurrently with high-fat meals. Thus, the coat-core formulation of nisoldipine appears to have overcome the limitations of the shorter duration of action of immediate-release nisoldipine. Nisoldipine coat-core is well tolerated and once-daily administration produces a long duration of effective anti-ischaemic relief in patients with chronic stable angina pectoris.

Impact of CK-MB testing policies on hospital length of stay and laboratory costs for patients with myocardial infarction or chest pain

We obtained data on hospital length of stay (LOS) and total laboratory charges for Medicare patients admitted to 82 hospitals in Massachusetts during 1994. Five Diagnosis Related Groups (DRGs) were selected: surviving acute myocardial infarction (AMI) with, and without, complications; AMI with death; angina pectoris; and chest pain. The hospitals were grouped according to their laboratory policies for testing CK-MB (e.g., frequency of assay runs; information obtained by telephone survey). The study was conducted to determine whether there was an association between turnaround times for results and LOS for cardiac DRGs. The mean LOS for AMIs with complication for 1513 patients admitted to 22 hospitals whose laboratories perform CK-MB testing once or twice daily was 8.4 days [95% confidence interval (CI): 8.2–8.7]. In contrast, the mean LOS for hospitals with CK-MB test policies of at least 3 runs daily or random-access stat was significantly (P &lt;0.05) lower, 7.7 days (CI: 7.4–8.0 and 7.5–7.9, respectively). Overall laboratory charges were lower in the hospitals with shorter LOS. With one exception, there was no significant difference in LOS between patients with DRGs of angina pectoris or chest pain or other AMI DRGs. For AMI, a CK-MB testing policy that produces shorter turnaround times may be justified because of an association with reductions in LOS and overall laboratory costs.

The influence of dosage form on aspirin kinetics: implications for acute cardiovascular use

In this study, the pharmacokinetics of several formulations of aspirin were examined: soluble aspirin, mouth-dispersible aspirin, plain aspirin and enteric-coated aspirin granules. Blood samples were taken at frequent intervals for 24 hours after single dosing in 12 healthy volunteers and Tmax, Cmax and t1/2 measured. Cmax was significantly higher for soluble aspirin than for the other formulations and the t1/2 was shorter. The results show the rapid absorption of aspirin from a soluble formulation compared with that from plain aspirin or enteric-coated aspirin granules. Recommendations to treat patients suspected of having a heart attack as soon as possible with aspirin are now widely accepted and the present study would suggest that soluble aspirin should be the aspirin of choice in this situation.

Physiologic effects of long-term hypertension control

Various antihypertensive agents may reduce blood pressure to a similar degree, yet they produce different outcomes with respect to long-term end-organ damage. Effective antihypertensive therapy can prevent or even reverse established left ventricular hypertrophy. The most rapid and extensive regression occurs with agents that block the reninangiotensin system or reduce entry of calcium into the cells. Other classes of drugs that reliably reverse left ventricular hypertrophy are centrally acting adrenergic inhibitors and beta blockers. The effect of antihypertensive agents on atherosclerosis appears to differ widely with regard to lipid metabolism, insulin sensitivity, and the biology of endothelium and vascular smooth muscle. Hypertension and chronic renal failure (diabetic and nondiabetic) are closely allied, but available antihypertensive agents are not equally potent in reducing intraglomerular pressure.