European Heart Journal: Acute Cardiovascular Care

Prehospital thrombolytic therapy given by ambulance emergency medical services to patients with acute ST-segment elevation myocardial infarction (STEMI) may produce earlier reperfusion than percutaneous coronary intervention. Clinical results from prehospital thrombolytic therapy in rural areas are scarce.

We studied outcomes during 11 years of a prehospital thrombolytic therapy system in rural sub-arctic Norway. Ambulance personnel gave protocol basic treatment and transmitted electrocardiograms to hospital physicians who made the decision for prehospital thrombolytic therapy. The study was divided into three time periods; 2000–2003, 2004–2007 and 2008–2011.

A total of 385 STEMI patients received prehospital thrombolytic therapy, median patient age was 61.2 years, and 77% were men. Time saved by prehospital reperfusion therapy was 131 minutes. The proportion who got prehospital thrombolytic therapy within 2 hours of symptom onset increased from 21% in 2000–2003 to 39% in 2008–2011 (P=0.003). The proportion who underwent coronary angiography or percutaneous coronary intervention within 24 hours of first medical contact increased from 56.4% to 95.4% (P<0.001). Post-STEMI systolic heart failure decreased from 19.4% to 8.1% (P=0.02), while 1-year mortality fell, non-significantly, by 50% over time to reach 5.6%. Thirteen patients suffered acute out-of-hospital cardiac arrest; all were successfully defibrillated. Ten patients had major bleeding events (2.6%).

A decentralised prehospital thrombolytic therapy system based on ambulance personnel, telemetry and centralised 7/24 invasive diagnosis and treatment service, combined with system maturation over time, was associated with earlier reperfusion, improved clinical outcomes and better survival. Prehospital thrombolytic therapy is a feasible and safe intervention used in rural settings with long evacuation lines to percutaneous coronary intervention facilities.

Pre-treatment with unfractionated heparin is common in ST-segment elevation myocardial infarction (STEMI) protocols, but the effect on intracoronary thrombus burden is unknown. We studied the effect of heparin pre-treatment on intracoronary thrombus burden and Thrombolysis in Myocardial Infarction (TIMI) flow prior to percutaneous coronary intervention in patients with STEMI.

The Thrombus Aspiration in ST-Elevation Myocardial Infarction in Scandinavia (TASTE) trial angiographically assessed intracoronary thrombus burden and TIMI flow, prior to percutaneous coronary intervention, in patients with STEMI. In this observational sub-study, patients pre-treated with heparin were compared with patients not pre-treated with heparin. Primary end points were a visible intracoronary thrombus and total vessel occlusion prior to percutaneous coronary intervention. Secondary end points were in-hospital bleeding, in-hospital stroke and 30-day all-cause mortality.

Heparin pre-treatment was administered in 2898 out of 7144 patients (41.0%). Patients pre-treated with heparin less often presented with an intracoronary thrombus (61.3% vs. 66.0%, p<0.001) and total vessel occlusion (62.9% vs. 71.6%, p<0.001). After adjustments, heparin pre-treatment was independently associated with a reduced risk of intracoronary thrombus (odds ratio (OR) 0.73, 95% confidence interval (CI)=0.65–0.83) and total vessel occlusion (OR 0.64, 95% CI=0.56–0.73), prior to percutaneous coronary intervention. There were no significant differences in secondary end points of in-hospital bleeding (OR 0.84, 95% CI=0.55–1.27), in-hospital stroke (OR 1.17, 95% CI=0.48–2.82) or 30-day all-cause mortality (hazard ratio 0.88, 95% CI=0.60–1.30).

Heparin pre-treatment was independently associated with a lower risk of intracoronary thrombus and total vessel occlusion before percutaneous coronary intervention in patients with STEMI, without evident safety concerns, in this large multi-centre observational study.

The role of thrombus aspiration plus primary percutaneous coronary intervention in ST-segment elevation myocardial infarction remains controversial.

We performed a meta-analysis of 25 randomised controlled trials in which 21,740 ST-segment elevation myocardial infarction patients were randomly assigned to thrombus aspiration plus primary percutaneous coronary intervention or primary percutaneous coronary intervention. Study endpoints were: death, myocardial infarction, stent thrombosis and stroke.

On pooled analysis, the risk of death (4.3% vs. 4.8%, odds ratio (OR) 0.90, 95% confidence interval (CI) 0.79–1.03; P=0.123), myocardial infarction (2.4% vs. 2.5%, OR 0.95, 95% CI 0.80–1.13; P=0.57) and stent thrombosis (1.3% vs. 1.6%, OR 0.80, 95% CI 0.63–1.01; P=0.066) was similar between thrombus aspiration plus primary percutaneous coronary intervention and primary percutaneous coronary intervention. The risk of stroke was higher in the thrombus aspiration plus primary percutaneous coronary intervention than the primary percutaneous coronary intervention group (0.84% vs. 0.59%, OR 1.401, 95% CI 1.004–1.954; P=0.047). However, on sensitivity analysis after removing the TOTAL trial, thrombus aspiration plus primary percutaneous coronary intervention was not associated with an increased risk of stroke (OR 1.01, 95% CI 0.58–1.78). The weak association between thrombus aspiration and stroke was also confirmed by the fact that the lower bound of the 95% CI was slightly below unity after removing either the study by Kaltoft or the ITTI trial. There was no interaction between the main study results and follow-up, evidence of coronary thrombus, or study sample size.

In patients with ST-segment elevation myocardial infarction, thrombus aspiration plus primary percutaneous coronary intervention does not reduce the risk of death, myocardial infarction or stent thrombosis. Thrombus aspiration plus primary percutaneous coronary intervention is associated with an increased risk of stroke; however, this latter finding appears weak.

High survival rates are commonly reported following primary percutaneous coronary intervention for ST-elevation myocardial infarction, with most contemporary studies reporting overall survival.

The aim of this study was to describe survival following primary percutaneous coronary intervention for ST-elevation myocardial infarction corrected for non-cardiovascular deaths by reporting relative survival and investigate clinically significant factors associated with poor long-term outcomes.

Using the prospective UK Percutaneous Coronary Intervention registry, primary percutaneous coronary intervention cases (n=88,188; 2005–2013) were matched to mortality data for the UK populace. Crude five-year relative survival was 87.1% for the patients undergoing primary percutaneous coronary intervention and 94.7% for patients <55 years. Increasing age was associated with excess mortality up to four years following primary percutaneous coronary intervention (56–65 years: excess mortality rate ratio 1.61, 95% confidence interval 1.46–1.79; 66-75 years: 2.49, 2.26–2.75; >75 years: 4.69, 4.27–5.16). After four years, there was no excess mortality for ages 56–65 years (excess mortality rate ratio 1.27, 0.95–1.70), but persisting excess mortality for older groups (66–75 years: excess mortality rate ratio 1.72, 1.30–2.27; >75 years: 1.66, 1.15–2.41). Excess mortality was associated with cardiogenic shock (excess mortality rate ratio 6.10, 5.72–6.50), renal failure (2.52, 2.27–2.81), left main stem stenosis (1.67, 1.54–1.81), diabetes (1.58, 1.47–1.69), previous myocardial infarction (1.52, 1.40–1.65) and female sex (1.33, 1.26–1.41); whereas stent deployment (0.46, 0.42–0.50) especially drug eluting stents (0.27, 0.45–0.55), radial access (0.70, 0.63–0.71) and previous percutaneous coronary intervention (0.67, 0.60–0.75) were protective.

Following primary percutaneous coronary intervention for ST-elevation myocardial infarction, long-term cardiovascular survival is excellent. Failure to account for non-cardiovascular death may result in an underestimation of the efficacy of primary percutaneous coronary intervention.

There are few data on the prognostic significance of the wall motion score index compared with left ventricle ejection fraction after an acute myocardial infarction. Our objective was to compare them after the hyperacute phase.

Transthoracic echocardiograms were performed in 352 consecutive patients with myocardial infarction, after the first 48 hours of admission and before hospital discharge (median 56.3 hours (48.2–83.1)). We evaluated the ability of the wall motion score index and left ventricular ejection fraction to predict the combined endpoint (mortality and rehospitalization for heart failure) as a primary objective and the independent events of the combined endpoint as a secondary objective.

In 80.7% of patients, the wall motion score index was high despite having an ejection fraction >40%. No patient had an ejection fraction <55% with a normal index. After a follow-up of 30.5 months (24.2–49.5), both variables were predictors of the composite endpoint and all-cause mortality (p<0.0001), although only the wall motion score index was a predictor of readmission for heart failure (p=0.007). By multivariate analysis, a wall motion score index >1.8 proved to be the most powerful predictor of the composite endpoint (hazard ratio: 8.5; 95% confidence interval 3.7–18.8; p<0.0001). The superiority of the wall motion score index over ejection fraction was especially significant in patients with less myocardial damage (non-ST elevation myocardial infarction, or left ventricle ejection fraction >40%).

Both variables provide important prognostic information after a myocardial infarction. Beyond the hyperacute phase, wall motion score index is a more powerful prognostic predictor, especially in subgroups with less myocardial damage.

Although the typical apical form of Takotsubo syndrome and anterior acute myocardial infarction have similar electrocardiographic and echocardiographic presentations, data on the clinical differences between the two disorders are limited.

Using the Tokyo Cardiovascular Care Unit network registry, we identified patients hospitalised with apical Takotsubo syndrome (n=540; 2010–2014) or anterior acute myocardial infarction (n=2,806; 2013–2014) and created 522 age and sex-matched pairs (mean age 74.1 years; women 78.5%). We compared the clinical characteristics and inhospital outcomes between the two groups.

On admission, patients with apical Takotsubo syndrome showed a lower body mass index, less frequent chest pain/tightness, lower systolic blood pressure, higher heart rate, lower creatine kinase, higher C-reactive protein and brain natriuretic peptide, and less frequent ST-elevation than patients with anterior acute myocardial infarction. Patients with apical Takotsubo syndrome received catecholamine (12.8% vs. 24.5%, P<0.001) and intra-aortic balloon pumping (5.9% vs. 15.1%, P<0.001) less frequently. Despite similar all-cause mortality (5.4% vs. 7.9%, P=0.134), patients with apical Takotsubo syndrome showed lower cardiac mortality (2.1% vs. 6.7%, P<0.001; risk difference −4.6% (95% confidence interval −7.1% to −2.1%)) but higher non-cardiac mortality (3.3% vs. 1.1%, P=0.033; 2.1% (0.3%–3.9%)). In subgroup comparisons, patients with physically triggered Takotsubo syndrome had higher non-cardiac mortality (7.0%) than those with non-physically triggered Takotsubo syndrome (1.2%, P=0.001) or anterior acute myocardial infarction (1.1%, P<0.001).

This study found that cardiac and non-cardiac mortality risks differed significantly between apical Takotsubo syndrome and anterior acute myocardial infarction. Our findings underscore the importance of differentiating between the two disorders for appropriate management.