The impact of initial treatment delay using primary angioplasty on mortality among patients with acute myocardial infarction: from the Korea acute myocardial infarction registry

Door-to-device time and mortality in patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention: insight from real world data of Thai PCI Registry

Background

Timely reperfusion therapy is recommended for patients with ST-segment elevation myocardial infarction (STEMI), and system delay <90 minutes and door-to-device (D2D) time <60 minutes are recommended by the 2017 ESC Guidelines for the management of STEMI patients and have been proposed as a performance measure for triaging patients for primary percutaneous coronary intervention (PCI). However, previous research produced contradictory results regarding the association between D2D time and mortality. Therefore, this study aimed to examine the associations between D2D time and mortality in Thailand.

Methods

This cohort study included STEMI patients treated with primary PCI in 39 PCI centres in Thailand from February 27, 2018, to August 1, 2019. Patients were eligible if they met the following criteria: primary STEMI diagnosis, symptom onset within 12 hours, and ST-segment elevation of at least 0.1 mV in 2 or more contiguous leads (at least 0.2 mV in V1-V3) or a new left bundle branch block.

Results

Within 12 hours of symptom onset, 3,874 patients underwent primary PCI. The median D2D time was 54 minutes [interquartile range (IQR) 29-90], and there was a significant difference between patients transferred from other hospitals (44 minutes, IQR 25-77, n=2,871) and patients presented directly to PCI centres (81 minutes, IQR 56-129, n=1,003) (P<0.001). Overall, in-hospital mortality was 7.8%. In a multivariable analysis, adjusting for other predictors of mortality and stratifying according to intervals of D2D time, cumulative in-hospital mortality was significantly higher in patients with a D2D time greater than 90 minutes [hazard ratio (HR) 1.5, 95% confidence interval (CI): 1.0-2.1, P=0.046] but not associated with D2D time shorter than 60 minutes (HR 1.2, 95% CI: 0.8-1.8, P=0.319).

Conclusions

A D2D time greater than 90 minutes was related to in-hospital mortality in patients with STEMI treated with primary PCI, but a D2D time less than 60 minutes was not consistently associated with D2D time-improved survival in real-world, contemporary practice in Thailand.

Coronary intervention door-to-balloon time and outcomes in ST-elevation myocardial infarction: a meta-analysis

OBJECTIVE

This study aims to determine the relationship between door-to-balloon delay in primary percutaneous coronary intervention and ST-elevation myocardial infarction (MI) outcomes and examine for potential effect modifiers.

METHODS

We conducted a systematic review and meta-analysis of prospective observational studies that have investigated the relationship of door-to-balloon delay and clinical outcomes. The main outcomes include mortality and heart failure.

RESULTS

32 studies involving 299 320 patients contained adequate data for quantitative reporting. Patients with ST-elevation MI who experienced longer (>90 min) door-to-balloon delay had a higher risk of short-term mortality (pooled OR 1.52, 95% CI 1.40 to 1.65) and medium-term to long-term mortality (pooled OR 1.53, 95% CI 1.13 to 2.06). A non-linear time-risk relation was observed (P=0.004 for non-linearity). The association between longer door-to-balloon delay and short-term mortality differed between those presented early and late after symptom onset (Cochran's Q 3.88, P value 0.049) with a stronger relationship among those with shorter prehospital delays.

CONCLUSION

Longer door-to-balloon delay in primary percutaneous coronary intervention for ST-elevation MI is related to higher risk of adverse outcomes. Prehospital delays modified this effect. The non-linearity of the time-risk relation might explain the lack of population effect despite an improved door-to-balloon time in the USA.

CLINICAL TRIAL REGISTRATION

PROSPERO (CRD42015026069).

[Hospital Arrival Rate within Golden Time and Factors Influencing Prehospital Delays among Patients with Acute Myocardial Infarction]

PURPOSE

This research was done to identify the hospital arrival rate and factors related to prehospital delay in arriving at an emergency medical center within the golden time after symptom onset in patients with acute myocardial infarction (AMI).

METHODS

Data used in the research was from the National Emergency Department Information System of the National Emergency Medical Center which reported that in 2014, 9,611 patients went to emergency medical centers for acute myocardial infarction. Prehospital time is the time from onset to arrival at an emergency medical center and is analyzed by subdividing arrival and delay based on golden time of 2 hour.

RESULTS

After onset of acute myocardial infarction, arrival rate to emergency medical centers within the golden time was 44.0%(4,233), and factors related to prehospital delay were gender, age, region of residence, symptoms, path to hospital visit, and method of transportation.

CONCLUSION

Results of this study show that in 2014 more than half of AMI patients arrive at emergency medical centers after the golden time for proper treatment of AMI. In order to reduce prehospital delay, new policy that reflects factors influencing prehospital delay should be developed. Especially, public campaigns and education to provide information on AMI initial symptoms and to enhance utilizing EMS to get to the emergency medical center driectly should be implemented for patients and/or caregivers.

Assessment of coronary care management and hospital mortality from ST-segment elevation myocardial infarction in the Kazakhstan population: Data from 2012 to 2015

OBJECTIVE

The aim of this study was to assess and evaluate factors related to coronary care management and hospital mortality in patients with ST-segment elevation myocardial infarction (STEMI) hospitalized in the Kazakhstan County and city hospitals in which percutaneous coronary intervention (PCI) was performed during the period of 2012-2015.

MATERIALS AND METHODS

A total of 22,176 adult patients (18> years) with acute STEMI were hospitalized from January 2012 to December 2015. All the investigated STEMI patients underwent PCI.

RESULTS

The mean age of STEMI patients was 61.52±11.48 years, 72.2% of the patients were male and 75.2% living in the rural regions. The mean time from hospitalization to PCI was 2104.41±5060.68min (median 95.0 and IQR 1034.5). The mean and median of time from hospitalization to PCI tended to decrease from 2747.7±5793.9min and 155.0min in 2012 to 1874.7±4759.2min and 73.5min in 2015. Among all STEMI events the percentage of patients from hospitalization to PCI within 0-59min was up to 39.0% during all study period. From 2012 to 2015, the percentage of STEMI patients with short time (0-59min) of hospitalization to PCI tended to increase in average by 11.4% per year (P=0.09). Among all STEMI patients hospital mortality from 2012 to 2015 did not change significantly and ranged from 9.0% in 2012 to 8.6% in 2015. By multiple logistic regression analysis, study years (2012), gender (female), age (60> years), time from hospitalization to PCI (60>min) and number of bed-days were statistically significant factors associated with patients' hospital mortality from STEMI with PCI.

CONCLUSIONS

The present study demonstrated that hospitalization delay in the treatment of STEMI patients in Kazakhstan population was without significant changes, meanwhile the number of patients perfused within 1h from hospitalization to PCI tended to increase during 2012-2015. The higher hospital mortality was associated with study year, female gender, older age, longer-time from hospitalization to PCI and shorter hospitalization.

Symptom-Onset-To-Balloon Time, ST-Segment Resolution and In-Hospital Mortality in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention in China: From China Acute Myocardial Infarction Registry

Animal and imaging study evidence favors early reperfusion for acute myocardial infarction. However, in clinical trials, the effect of symptom-onset-to-balloon (S2B) time on clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI) has been inconsistent. Moreover, there are few data regarding the ischemic time in China. A total of 3,877 consecutive patients with STEMI with available S2B time undergoing pPCI from January 2013 to September 2014 at 108 hospitals that participated in the China Acute Myocardial Infarction registry were included and stratified into 3 S2B groups: <6 hours, 6 to 12 hours, >12 hours S2B time was tested in multivariate logistic regression analyses as an independent risk factor of mortality (primary outcome), major adverse cardiovascular and cerebrovascular events (MACCE), and impaired myocardial perfusion (secondary outcomes). The median S2B time was 5.5 (3.75 to 8.50) hours. Longer S2B time was associated with higher in-hospital mortality (<6 hours: 2.7%; 6 to 12 hours: 3.4%; >12 hours: 4.9%; p = 0.047) and ST-segment resolution <50% (<6 hours: 16.7%; 6 to 12 hours: 19.2%; >12 hours: 24.3%; p = 0.002) but not MACCE. In multivariate-adjusted analysis, S2B >12 hours remained associated with ST-segment resolution <50% (odds ratio 1.53, 95% confidence interval 1.16 to 2.01, p = 0.002) but not with in-hospital mortality (odds ratio 1.673, 95% confidence interval 0.95 to 2.94, p = 0.073). In conclusion, median S2B time in patients with STEMI undergoing pPCI was longer than that in registry studies from other countries. Longer S2B time was associated with impaired myocardial perfusion but not with in-hospital mortality or MACCE.

Symptom-to-door delay among patients with ST-segment elevation myocardial infarction in Singapore

OBJECTIVES

Symptom-to-door time (S2D) is one of the important components of ischaemic time, which might affect the infarct size and outcomes of acute myocardial infarction. The aim of the present study was to identify patients' characteristics associated with delayed symptom-onset-to-arrival at EDs in ST-segment elevation myocardial infarction (STEMI) patients in Singapore.

METHODS

Retrospective data of STEMI patients presenting to the ED of all public hospitals with onsite primary percutaneous coronary intervention facilities between 2010 and 2012 were obtained from the Singapore Myocardial Infarction Registry. Based on the S2D of 120 min, characteristics of patients were compared between short S2D (≤120 min) and long S2D (>120 min). Multivariate logistic and linear regression analyses were performed.

RESULTS

Out of 3848 patients, 1682 patients had an S2D of ≤120 min, and 2166 had an S2D >120 min. In the multivariate analyses, older age, Malay ethnicity, diabetes mellitus, presenting symptoms of back and epigastric pain were independently associated with long S2D. Patients who utilised the emergency medical services, presented after office hours and with symptoms of chest pain, breathlessness, diaphoresis and past history of percutaneous transluminal coronary angioplasty/primary percutaneous coronary intervention, were independently associated with short S2D. Patients with long S2D had lower probability of receiving reperfusion treatment with delayed symptom-to-balloon and door-to-balloon time and higher probabilities of complications and mortality.

CONCLUSION

The present study shows that longer S2D was associated with older age, ethnicity, diabetes mellitus, delay in receiving early reperfusion treatment and poorer prognosis.

Relationship between time to treatment and mortality among patients undergoing primary percutaneous coronary intervention according to Korea Acute Myocardial Infarction Registry

BACKGROUND

Despite large reductions in door-to-balloon times over the period, several studies from regional and national data showed that annual mortality rates were not decreased among patients who underwent primary percutaneous coronary intervention (PCI). However, these studies mostly focused on door-to-balloon time, and there was no consideration of total ischemic time in a trend of mortality. The aim of this study was to assess the annual trend between time to treatment and 1-month mortality among patients undergoing primary PCI.

METHODS AND RESULTS

The study population consisted of 8040 patients who underwent primary PCI at hospitals participating in the nationwide prospective Korea Acute Myocardial Infarction Registry (KAMIR) between January 2008 and December 2011. The primary end point of this study was 1-month all-cause mortality, and time to treatment (door-to-balloon time, symptom-to-balloon time). One-month death occurred in 452 patients (5.6%) from 2008 to 2011. Additional reductions in door-to-balloon time were not translated into parallel reductions in mortality rate and total ischemic time. After adjustment using clinical risk, shorter total ischemic time was an independent predictor of 1-month mortality [adjusted odds ratio (OR) 0.78, 95% confidential interval (CI) 0.62-0.99, p=0.04]. Total ischemic time could be reduced by using emergency medical services.

CONCLUSION

Despite improvements in door-to-balloon time, no parallel reductions in mortality rate and total ischemic time were observed. Total ischemic time was associated with mortality. The present study suggests that additional efforts are needed to shorten total ischemic time including patient and pre-hospital systemic delay for better prognosis after primary PCI.

Current trend of acute myocardial infarction in Korea (from the Korea Acute Myocardial Infarction Registry from 2006 to 2013)

Although the incidence of acute myocardial infarction (AMI) in Korea has been rapidly changed because of westernization of diet, lifestyle, and aging of the population, the recent trend of the myocardial infarction have not been reported by classification. We investigated recent trends in the incidence and mortality associated with the 2 major types of AMI. We reviewed 39,978 patients registered in the Korea Acute Myocardial Infarction Registry for either ST-segment elevation acute myocardial infarction (STEMI) or non-ST-segment elevation acute myocardial infarction (NSTEMI) from 2006 to 2013. When the rate for AMI were investigated according to each year, the incidence rates of STEMI decreased markedly from 60.5% in 2006 to 48.1% in 2013 (p <0.001). In contrast, a gradual increase in the incidence rates of NSTEMI was observed from 39.5% in 2006 to 51.9% in 2013 (p <0.001). As risk factors, hypertension, diabetes mellitus, and dyslipidemia were much more common in patients with NSTEMI than STEMI. Among medical treatments, the use of β blockers, angiotensin receptor blocker, and statin were increased from 2006 to 2013 in patients with STEMI and NSTEMI. Patients with STEMI and NSTEMI were more inclined to be increasingly treated by invasive treatments with percutaneous coronary intervention. In conclusion, this study demonstrated that the trend of myocardial infarction has been changed rapidly in the aspect of risk factors, ratio of STEMI versus NSTEMI, and therapeutic strategies during the recent 8 years in Korea.

The scientific achievements of the decades in Korean Acute Myocardial Infarction Registry

The Korea Acute Myocardial Infarction Registry (KAMIR) was the first nationwide registry data collection designed to track outcomes of patients with acute myocardial infarction (AMI). These studies reflect the current therapeutic approaches and management for AMI in Korea. The results of KAMIR could help clinicians to predict the prognosis of their patients and identify better diagnostic and treatment tools to improve the quality of care. The KAMIR score was proposed to be a predictor of the prognosis of AMI patients. Triple antiplatelet therapy, consisting of aspirin, clopidogrel and cilostazol, was effective at preventing major adverse clinical outcomes. Drug-eluting stents were effective and safe in AMI patients with no increased risk of stent thrombosis. Statin therapy was effective in Korean AMI patients, including those with very low levels of low density cholesterol. The present review summarizes the 10-year scientific achievements of KAMIR from admission to outpatient care during long-term clinical follow-up.

Performance of reperfusion therapy and hospital mortality in ST-elevation myocardial infarction patients with non-chest pain complaints

PURPOSE

ST-elevation myocardial infarction (STEMI) patients may visit the emergency department (ED) complaining of sensations of pain other than the chest. We investigated our performance of reperfusion therapy for STEMI patients presenting with non-chest pains.

MATERIALS AND METHODS

This was a retrospective observational cohort study. STEMI patients who underwent primary percutaneous coronary intervention (PCI) were divided into a chest pain group and a non-chest pain group. Clinical differences between the two groups and the influence of presenting with non-chest pains on door-to-electrocardiograms (ECG) time, door-to-balloon time, and hospital mortality were evaluated.

RESULTS

Of the 513 patients diagnosed with STEMI, 93 patients presented with non-chest pains. Patients in the non-chest pain group were older, more often female, and had a longer symptom onset to ED arrival time and higher Killip class than patients in the chest pain group. There was a statistically significant delay in door-to-ECG time (median, 2.0 min vs. 5.0 min; p<0.001) and door-to-balloon time (median, 57.5 min vs. 65.0 min; p<0.001) in patients without chest pain. In multivariate analysis, presenting with non-chest pains was an independent predictor for hospital mortality (odds ratio, 2.3; 95% confidence interval, 1.1-4.7). However, door-to-ECG time and door-to-balloon time were not factors related to hospital mortality.

CONCLUSION

STEMI patients presenting without chest pain showed higher baseline risk and hospital mortality than patients presenting with chest pain. ECG acquisition and primary PCI was delayed for patients presenting with non-chest pains, but not influencing hospital mortality. Efforts to reduce pre-hospital time delay for these patients are necessary.

Evaluation of gender differences in Door-to-Balloon time in ST-elevation myocardial infarction

BACKGROUND

A delayed Door-to-Balloon (DTB) time in women with ST-elevation myocardial infarction (STEMI) has been associated with an increased mortality. The objectives of this study were to (a) quantify the components of the delayed DTB time in women and (b) assess the independent effect of gender on DTB time in patients undergoing percutaneous coronary intervention (PCI) for STEMI.

METHODS

Clinical parameters were prospectively collected for 735 STEMI patients undergoing primary PCI from 2006 to 2010, with particular attention to the components of DTB time, including the onset of chest pain and the 'code' notification of the STEMI team by the Emergency Department.

RESULTS

Women were significantly older with more co-morbidity. Upon hospital arrival they also experienced delays in Door-to-Code (23 vs. 17 min, P=.012), Code-to-Balloon (63 vs. 57 min, P=.001) and thus DTB time (88 vs. 72 min, P=.001). After multivariate adjustment, independent determinants of DTB time included female gender (ratio of geometric means [RGM]=1.13; 95% CI 1.02-1.26; P=.022), hypertension (RGM=1.12, 95% CI 1.02-1.23, P=.014), maximum ST-elevation (RGM=0.97, 95% CI 0.94-0.98, P<.001), office hours (RGM=0.84, 95% CI 0.78-0.92, P<.001) and triage category (RGM=1.23, 95% CI 1.09-1.40, P=.001).

CONCLUSIONS

Women experience delays in identification of the STEMI diagnosis and also in the PCI process. Thus a multifaceted approach addressing both the diagnosis and management of STEMI in women is required.

Factors related to prehospital time delay in acute ST-segment elevation myocardial infarction

Despite recent successful efforts to shorten the door-to-balloon time in patients with acute ST-segment elevation myocardial infarction (STEMI), prehospital delay remains unaffected. Nonetheless, the factors associated with prehospital delay have not been clearly identified in Korea. We retrospectively evaluated 423 patients with STEMI. The mean symptom onset-to-door time was 255 ± 285 (median: 150) min. The patients were analyzed in two groups according to symptom onset-to-door time (short delay group: ≤ 180 min vs long delay group: > 180 min). Inhospital mortality was significantly higher in long delay group (6.9% vs 2.8%; P = 0.048). Among sociodemographic and clinical variables, diabetes, low educational level, triage via other hospital, use of private transport and night time onset were more prevalent in long delay group (21% vs 30%; P = 0.038, 47% vs 59%; P = 0.013, 72% vs 82%; P = 0.027, 25% vs 41%; P < 0.001 and 33% vs 48%; P = 0.002, respectively). In multivariate analysis, low educational level (1.66 [1.08-2.56]; P = 0.021), symptom onset during night time (1.97 [1.27-3.04]; P = 0.002), triage via other hospital (1.83 [1.58-5.10]; P = 0.001) and private transport were significantly associated with prehospital delay (3.02 [1.81-5.06]; P < 0.001). In conclusion, prehospital delay is more frequent in patients with low educational level, symptom onset during night time, triage via other hospitals, and private transport, and is associated with higher inhospital mortality.

Clinical benefit of low molecular weight heparin for ST-segment elevation myocardial infarction patients undergoing primary percutaneous coronary intervention with glycoprotein IIb/IIIa inhibitor

The efficacy of low molecular weight heparin (LMWH) with low dose unfractionated heparin (UFH) during percutaneous coronary intervention (PCI) with or without glycoprotein (Gp) IIb/IIIa inhibitor compared to UFH with or without Gp IIb/IIIa inhibitor has not been elucidated. Between October 2005 and July 2007, 2,535 patients with ST elevation acute myocardial infarction (STEMI) undergoing PCI in the Korean Acute Myocardial Infarction Registry (KAMIR) were assigned to either of two groups: a group with Gp IIb/IIIa inhibitor (n=476) or a group without Gp IIb/IIIa inhibitor (n=2,059). These groups were further subdivided according to the use of LMWH with low dose UFH (n=219) or UFH alone (n=257). The primary end points were cardiac death or myocardial infarction during the 30 days after the registration. The primary end point occurred in 4.1% (9/219) of patients managed with LMWH during PCI and Gp IIb/IIIa inhibitor and 10.8% (28/257) of patients managed with UFH and Gp IIb/IIIa inhibitor (odds ratio [OR], 0.290; 95% confidence interval [CI], 0.132-0.634; P=0.006). Thrombolysis In Myocardial Infarction (TIMI) with major bleeding was observed in LMHW and UFH with Gp IIb/IIIa inhibitor (1/219 [0.5%] vs 1/257 [0.4%], P=1.00). For patients with STEMI managed with a primary PCI and Gp IIb/IIIa inhibitor, LMWH is more beneficial than UFH.

Clinical effects of hypertension on the mortality of patients with acute myocardial infarction

The incidence of ischemic heart disease has been increased rapidly in Korea. However, the clinical effects of antecedent hypertension on acute myocardial infarction have not been identified. We assessed the relationship between antecedent hypertension and clinical outcomes in 7,784 patients with acute myocardial infarction in the Korea Acute Myocardial Infarction Registry during one-year follow-up. Diabetes mellitus, hyperlipidemia, cerebrovascular disease, heart failure, and peripheral artery disease were more prevalent in hypertensives (n=3,775) than nonhypertensives (n=4,009). During hospitalization, hypertensive patients suffered from acute renal failure, shock, and cerebrovascular event more frequently than in nonhypertensives. During follow-up of one-year, the incidence of major adverse cardiac events was higher in hypertensives. In multi-variate adjustment, old age, Killip class > or =III, left ventricular ejection fraction <45%, systolic blood pressure <90 mmHg on admission, post procedural TIMI flow grade < or =2, female sex, and history of hypertension were independent predictors for in-hospital mortality. However antecedent hypertension was not significantly associated with one-year mortality. Hypertension at the time of acute myocardial infarction is associated with an increased rate of in-hospital mortality.

Differences in Clinical Outcomes Between Patients With ST-Elevation Versus Non-ST-Elevation Acute Myocardial Infarction in Korea

In Korea, the incidence of acute myocardial infarction has been increasing rapidly. Twelve-month clinical outcomes for 13,133 patients with acute myocardial infarction enrolled in the nationwide prospective Korea Acute Myocardial Infarction Registry study were analyzed according to the presence or absence of ST-segment elevation. Patients with ST-segment elevation myocardial infarction (STEMI) were younger, more likely to be men and smokers, and had poorer left ventricular function with a higher incidence of cardiac death compared to patients with non-ST-segment elevation myocardial infarction (NSTEMI). NSTEMI patients had a higher prevalence of 3-vessel and left main coronary artery disease with complex lesions, and were more likely to have co-morbidities. The in-hospital and 1-month survival rates were higher in NSTEMI patients than in STEMI patients. However, 12-month survival rates was not different between the two groups. In conclusion, NSTEMI patients have worse clinical outcomes than STEMI patients, and therefore should be treated more intensively during clinical follow-up.

Relation of left ventricular infarct transmurality and infarct size after primary percutaneous coronary angioplasty to time from symptom onset to balloon inflation

This study was performed to evaluate the impact of time to reperfusion on infarct size and transmurality after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). In 73 patients undergoing primary PCI for STEMI, contrast-enhanced magnetic resonance imaging was performed. Infarct size and transmurality on delayed-enhancement imaging were measured. Infarct size was not associated with symptom onset-to-balloon time (23 +/- 9% for <180 minutes, 22 +/- 9% for 180 to 360 minutes, and 24 +/- 11% for >360 minutes, p = 0.62) or door-to-balloon time (23 +/- 8% for <90 minutes, 23 +/- 10% for 90 to 120 minutes, and 22 +/- 11% for >120 minutes, p = 0.88). Infarct transmurality increased significantly with a delay of symptom onset-to-balloon time (73 +/- 22% for <180 minutes, 78 +/- 14% for 180 to 360 minutes, and 86 +/- 14% for >360 minutes, p = 0.04), but not for door-to-balloon time (79 +/- 15% for <90 minutes, 76 +/- 19% for 90 to 120 minutes, and 81 +/- 18% for >120 minutes, p = 0.62). In multivariate analysis, anterior infarction (odds ratio 4.15, 95% confidence interval 1.31 to 13.18, p = 0.02) and myocardial blush grade 0/1 (odds ratio [OR] 3.89, 95% confidence interval [CI] 1.13 to 13.51, p = 0.03) independently predicted a large infarct (infarct size > or =25%). Symptom onset-to-balloon time (OR per 30 minutes 1.26, 95% CI 1.04 to 1.53, p = 0.02) was an independent predictor of transmural infarct (average transmural extent > or =75%) and use of glycoprotein IIb/IIIa inhibitors showed a protective effect (OR 0.09, 95% CI 0.02 to 0.53, p = 0.007). In conclusion, symptom onset-to-balloon time was significantly associated with infarct transmurality but not infarct size in patients undergoing primary PCI for STEMI.