Immediate and long-term prognostic significance of a first anterior versus first inferior wall Q-wave acute myocardial infarction. Secondary Prevention Reinfarction Israeli Nifedipine Trial (SPRINT) Study Group

Circulating Small Extracellular Vesicles Reflect the Severity of Myocardial Damage in STEMI Patients

Circulating small extracellular vesicles (sEVs) contribute to inflammation, coagulation and vascular injury, and have great potential as diagnostic markers of disease. The ability of sEVs to reflect myocardial damage assessed by Cardiac Magnetic Resonance (CMR) in ST-segment elevation myocardial infarction (STEMI) is unknown. To fill this gap, plasma sEVs were isolated from 42 STEMI patients treated by primary percutaneous coronary intervention (pPCI) and evaluated by CMR between days 3 and 6. Nanoparticle tracking analysis showed that sEVs were greater in patients with anterior STEMI (p = 0.0001), with the culprit lesion located in LAD (p = 0.045), and in those who underwent late revascularization (p = 0.038). A smaller sEV size was observed in patients with a low myocardial salvage index (MSI, p = 0.014). Patients with microvascular obstruction (MVO) had smaller sEVs (p < 0.002) and lower expression of the platelet marker CD41-CD61 (p = 0.039). sEV size and CD41-CD61 expression were independent predictors of MVO/MSI (OR [95% CI]: 0.93 [0.87-0.98] and 0.04 [0-0.61], respectively). In conclusion, we provide evidence that the CD41-CD61 expression in sEVs reflects the CMR-assessed ischemic damage after STEMI. This finding paves the way for the development of a new strategy for the timely identification of high-risk patients and their treatment optimization.

Effects of Myocardial Perfusion Defect on the Frontal QRS-T Angle in Anterior Versus Inferior Myocardial Infarction

Objective The frontal QRS-T angle on a 12-lead electrocardiogram (ECG) has recently become accepted as a variable of ventricular repolarization. We compared the effects of myocardial perfusion defect (MPD) on the frontal QRS-T angle between anterior and inferior myocardial infarction (MI) using single-photon emission computed tomography. Methods The frontal QRS-T angle was defined as the absolute value of the difference between the frontal plane QRS axis and T-wave axis. A QRS-T angle more than 90° was considered abnormal. Patients Forty-two patients with anterior MI and 42 age- and sex-matched patients with inferior MI were enrolled. For controls, 42 age- and sex-matched patients with no MPD were selected. Results The mean frontal QRS-T angles in anterior MI, inferior MI and control subjects were 94.7±46.2°, 26.7±22.1° and 27.0±23.2°, respectively. Compared with controls, the frontal QRS-T angle was larger in anterior MI subjects (p<0.001), and similar in value to that in inferior MI subjects (p=0.69). An abnormal QRS-T angle was frequent in the anterior MI subjects than the inferior MI subjects (55% vs. 2%, p<0.001). In anterior MI subjects, MPD was significantly associated with the T-wave axis (ρ=0.46, p=0.002) and QRS-T angle (ρ=0.47, p=0.002), but was not with the QRS axis (ρ=0.07, p=0.66). In inferior MI subjects, there were no associations between MPD and the ECG variables. Conclusion Our data suggest that the frontal QRS-T angle in inferior MI subjects is not increased as evidently as that in anterior MI subjects.

Predictors of mortality in patients with non-anterior ST-segment elevation myocardial infarction: Analysis from the HORIZONS-AMI trial

OBJECTIVES

We sought to identify clinical, electrocardiographic (ECG), and angiographic characteristics that are predictive of 3-year mortality after primary percutaneous coronary intervention (PCI) in patients with non-anterior ST-elevation myocardial infarction (NA-STEMI) from the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial.

BACKGROUND

Which patients with NA-STEMI undergoing PCI have a poor prognosis is uncertain.

METHODS

NA-STEMI was defined as ST-segment elevation in lateral (V5, V6, I, aVL), inferior (II, III, aVF), or inferolateral (I, II, III, aVF, and V5-V6) ECG leads or posterior myocardial infarction with ST-segment depression of ≥1 mm in ≥2 contiguous anterior leads. Cox regression was used to identify independent predictors of 3-year mortality. Missing data were imputed using multiple imputation.

RESULTS

In HORIZONS-AMI, 2,578/3,602 patients had no prior coronary artery bypass grafting, underwent single-vessel PCI, and had baseline ECG data assessed in an independent core laboratory. Among them, 1,495 (58.0%) had NA-STEMI. Patients with NA-STEMI had lower 3-year mortality risk than those with anterior STEMI (4.5% versus 7.1%, P = 0.004). The independent predictors of increased 3-year mortality in NA-STEMI were older age (median > 59.0 years), diabetes, reduced LVEF (≤50%), Killip class ≥2, post-procedure TIMI flow 0-2 versus 3, renal insufficiency, and ST-resolution <30% at 60 min post-PCI. Patients with 0, 1, 2, 3, and ≥4 of these risk factors had 3-year mortality rates of 1.8%, 2.3%, 3.1%, 6.1%, and 36.3%, respectively (P < 0.0001).

CONCLUSIONS

Although NA-STEMI carries a better prognosis than anterior STEMI, high-risk patient cohorts with NA-STEMI may be identified who have substantial 3-year mortality.

Prevalence and Clinical Implication of Wellens' Sign in Patients With Non-ST-Segment Elevation Myocardial Infarction

Background

Symmetrically inverted or biphasic T waves in anterior precordial leads, Wellens’ sign, have been shown to represent impending infarction of left anterior descending (LAD) territory among unstable angina patients in the studies published more than 3 decades ago, when non-ST-segment elevation myocardial infarction (NSTEMI) was not a recognized entity. The clinical implication of Wellens’ sign in the contemporary NSTEMI cohort has not been clarified.

Methods

We performed a retrospective analysis of all NSTEMI patients who underwent coronary angiography between January 2013 and June 2014. Wellens’ sign was defined as either symmetrically inverted T waves (≥ 0.10 mV) or biphasic T waves in both leads V2 and V3. Coronary angiograms were reviewed and culprit lesions were determined for each patient.

Results

A total of 274 patients were included in the final analysis, of whom 24 (8.8%) had Wellens’ sign. Among these 24 patients, 16 had a LAD culprit (eight proximal), two had a non-LAD culprit, and six had non-obstructive coronary artery disease. Patients with Wellens’ sign were more likely to have LAD culprit (66.7% vs. 19.6%, P < 0.001) and proximal LAD culprit (33.3% vs. 14.4%, P = 0.035) than those without it. Wellens’ sign had a sensitivity of 24.6% and a specificity of 96.2% to predict LAD culprit.

Conclusions

Our study revealed that: 1) Wellens’ sign was seen in 8.8% of the patients with NSTEMI; 2) Two-thirds of patients with Wellens’ sign had LAD culprit and one-third had proximal LAD culprit; and 3) Sensitivity and specificity of Wellens’ sign to predict LAD culprit were 24.6% and 96.2%, respectively.

Prognostic value of location and type of myocardial infarction in the setting of advanced left ventricular dysfunction

Location (anterior) and type (Q wave) of myocardial infarction (MI) might be considered of prognostic significance when predicting mortality. However, there are limited data regarding the prognostic significance of type and location of MI in patients with severely depressed left ventricular function. In 1,221 patients in the MADIT II, Q-wave MI was observed in 763 patients (62%), 115 (10%) had non-Q-wave MI, and 343 (28%) had conduction abnormalities. In patients with Q-wave MI, anterior MI was present in 430 (57%), inferior in 155 (20%), and combined in 178 (23%) patients. Study end points included all-cause mortality, hospitalization or death due to worsening congestive heart failure, and episodes of ventricular tachycardia or ventricular fibrillation requiring implantable cardioverter-defibrillator therapy. In a multivariate Cox proportional hazard model predicting mortality, the following clinical variables entered the predictive model at a p value <0.10: treatment (implantable cardioverter-defibrillator vs conventional therapy), age dichotomized at 65 years, angina pectoris, ejection fraction dichotomized at 25%, serum urea nitrogen dichotomized at 25 mg/dl, and beta-blocker use. After adjustment for these covariates, risk of mortality was not significantly different in non-Q-wave MI versus Q-wave MI. However, when analyzing location of MI, inferior wall MI was associated with a significantly (hazard ratio 1.58, p = 0.048) higher risk of mortality than anterior wall MI. In addition, patients with conduction abnormalities had a higher risk of mortality (hazard ratio 1.36, p = 0.088) than patients with anterior wall MI. In conclusion, in the setting of severely depressed ejection fraction (< or =30%), inferior wall MI was associated with a significantly higher risk of mortality than anterior wall MI.

Lack of Additional Benefit of Intracoronary Transplantation of Autologous Peripheral Blood Stem Cell in Patients With Acute Myocardial Infarction

BACKGROUND

Recently the potential of myocardial repair by transplantation of autologous bone marrow stem cells has been suggested. Whether the additional intracoronary transplantation of autologous peripheral blood stem cells (PBSC), which were mobilized by granulocyte-colony-stimulating factor (G-CSF), could safely improve myocardial function in patients with acute myocardial infarction (AMI) was investigated.

METHODS AND RESULTS

Seventy-three patients with AMI who had successfully undergone percutaneous coronary intervention (PCI) were enrolled in the present prospective nonrandomized open-labeled study. Ten patients with elective PCI received G-CSF for 4 days followed by intracoronary PBSC transplantation. Thirty-two patients with primary PCI and 31 patients with recent AMI and elective PCI served as controls. The left ventricular (LV) function was evaluated using echocardiography and magnetic resonance imaging. G-CSF and intracoronary transplantation of PBSC did not incur any periprocedural myocardial damage. After 6 months, the LV ejection fraction was significantly improved in the cell therapy group. For 2 years of the follow-up period, there was no adverse clinical events, except one asymptomatic in-stent restenosis. However, comparable improvement of the LV ejection fraction was also identified in the primary PCI and elective PCI control groups.

CONCLUSIONS

In the present study, additional intracoronary infusion of PBSC was safe and feasible for the patients with AMI who had undergone PCI, but did not lead to a significant improvement in LV function compared to standard reperfusion treatment.

Sympathetic Drive in Anterior and Inferior Uncomplicated Acute Myocardial Infarction

Background— The sympathetic activation that follows acute myocardial infarction (AMI) has been associated with increased morbidity and mortality. Because the prognosis after anterior AMI (ant-AMI) is worse than that after inferior AMI (inf-AMI), we planned to determine whether the magnitude of sympathetic hyperactivity differs between the two.

Methods and Results— Thirty-nine patients with uncomplicated AMI, comprising 2 matched groups of 17 patients with ant-AMI, and 22 patients with inf-AMI were examined. Measurements were obtained 2 to 4 days after AMI and compared with 20 normal subjects (NC) who were matched in terms of age and body weight to the AMI groups. Resting muscle sympathetic nerve activity was quantified from multiunit bursts (MSNA) and from single units (s-MSNA). Both groups of AMI patients were matched with regard to hemodynamic variables, left ventricular function, and infarct size. Both groups had greater (at least P <0.01) sympathetic nerve activity than NC (60±4.3 bursts/100 cardiac beats and 68±4.9 impulses/100 cardiac beats), but the magnitude of sympathetic nerve hyperactivity in ant-AMI (81±4.0 bursts/100 cardiac beats and 91±4.9 impulses/100 cardiac beats) was similar ( P >0.05) to that in inf-AMI (80±3.2 bursts/100 cardiac beats and 90±4.0 impulses/100 cardiac beats)

Conclusions— Both ant-AMI and inf-AMI resulted primarily in a similar magnitude of sympathetic nerve hyperactivity. These findings suggest that the worse prognosis after ant-AMI compared with after inf-AMI would not be related primarily to the degree of sympathetic hyperactivity.

Antihypertensive drugs and the sympathetic nervous system

The sympathetic nervous system (SNS) plays an important role in the regulation of blood pressure homeostasis and cardiac function. Furthermore, the increased SNS activity is a predictor of mortality in patients with hypertension, coronary artery disease and congestive heart failure. Experimental data and a few clinical trials suggest that there are important interactions between the main pressor systems, i.e. the SNS, the renin-angiotensin system and the vascular endothelium with the strongest vasoconstrictor, endothelin. The main methods for the assessment of SNS activity are described. Cardiovascular drugs of different classes interfere differently with the SNS and the other pressor systems. Pure vasodilators including nitrates, alpha-blockers and dihydropyridine (DHP)-calcium channel blockers increase SNS activity. Finally, central sympatholytics and possibly phenylalkylamine-type calcium channel blockers reduce SNS activity. The effects of angiotensin-II receptor antagonists on SNS activity in humans is not clear; experimental data are discussed in this review. There are important interactions between the pressor systems under experimental conditions. Recent studies in humans suggest that an activation of the SNS with pure vasodilators in parallel increases plasma endothelin. It can be assumed that, in cardiovascular diseases with already enhanced SNS activity, drugs which do not increase SNS activity or even lower it are preferable. Whether this reflects in lower mortality needs to be investigated in intervention trials.

Trends in treatment and outcomes for acute myocardial infarction: 1975-1995

PURPOSE

To review the trends in treatment and survival for patients with acute myocardial infarction over the last 20 years.

MATERIAL AND METHODS

Studies were identified through MEDLINE searches and review of study bibliographies. Additional data were obtained from the Health Care Financing Administration including data from Medicare claims files (part A). Thirty-day mortality rates were calculated using Medicare data and case fatality rates from the National Hospital Discharge Survey. Published meta-analyses were used to determine treatment effects. Published studies were included if they reported the use of therapies for acute myocardial infarction at a population level. Trends in the demographic characteristics of the patients as well as infarct characteristics, medication use, and revascularization were recorded.

RESULTS

The use of acute treatments that are known to improve survival among patients with myocardial infarction has increased markedly during the last 20 years, leading to an estimated 9.6% reduction (from 27.0% to 17.4%) in 30-day mortality. After adjusting for potential interactions between therapies, the increase in use of aspirin, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and reperfusion can explain 71% of the decrease in the 30-day age- and sex-adjusted mortality rate from 1975 to 1995. The greatest effect of a given therapy was that of aspirin, which accounted for 34% of the decrease in 30-day mortality, followed by thrombolysis (17%), primary angioplasty (10%), beta-blockers (7%), and ACE inhibitors (3%). If other treatments (such as heparin or nonprimary angioplasty), whose effects on mortality are less certain, are included, up to 90% of the decrease in 30-day mortality can be explained by changes in treatment.

CONCLUSIONS

The primary reason for the decrease in early mortality from myocardial infarction during the last 20 years appears to be increased use of effective treatments.

[Clinical prediction of the early prognosis in acute myocardial infarct]

Several clinical factors can influence the pathophysiology, clinical course and prognosis of acute myocardial by different means. Some of them may be easily detected through the history, physical examination or ECG in an early phase. The knowledge of these factors may help the therapeutic decision making of patients with myocardial infarction. The influence for the main clinical factors (age, sex, risk factors, cardiologic antecedents and evolutive findings) on the short-term prognosis of acute myocardial infarction is reviewed. An analysis of the likely mechanisms of the influence of these factors on infarct prognosis is also performed.

Comparison of short- and long-term prognosis in patients with anterior wall versus inferior or lateral wall non-Q-wave acute myocardial infarction. Secondary Prevention Reinfarction Israeli Nifedipine Trial (SPRINT) Study Group

We evaluated the early and long-term prognosis of patients with a first non-Q-wave acute myocardial infarction (AMI) in relation to infarct site. Among 4,314 patients with a first AMI, 610 (14%) had a non-Q-wave AMI. Of them, 248 patients with anterior wall AMI were compared with 327 patients with inferior/lateral AMI. Baseline clinical characteristics were similar in both groups except for higher mean age in the anterior wall group. In-hospital complications were more common among patients with anterior wall AMI than in the inferior/lateral group. Patients with anterior wall AMI also had higher rates of in-hospital (15%), 1-year (12%), and 5-year (36%) postdischarge mortality compared with the inferior/lateral infarction group (10%, 6%, and 22%, respectively). The 1-year cardiac event rate (recurrent AMI and cardiac death) was significantly higher among the anterior wall AMI group than the inferior/lateral AMI group (14.2% and 4.8% respectively, p = 0.001). After adjustment for age, gender, systemic hypertension, diabetes mellitus, prior angina, and treatment with various medications, an increased risk for 1-year (odds ratio 1.31, 95% confidence interval [CI] 0.62 to 2.78) and 5-year mortality (relative risk 1.29, 95% CI 0.90 to 1.85) was observed, but it did not reach statistical significance. Anterior wall AMI location emerged as a predictor for higher 1-year cardiac event rate (odds ratio 3.15, 95% CI 1.59 to 6.78). These findings suggest that AMI location is an important prognostic variable for risk stratification of patients with a first non-Q-wave AMI.