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Patients with ST-segment elevation myocardial infarction (STEMI) experience major adverse cardiac events (MACEs) following primary percutaneous coronary intervention (PCI). Although the relationship between time to treatment (eg, door-to-balloon time, symptom onset-to-balloon time, and symptom onset-to-door time) and 1-month all-cause mortality was assessed previously, its relationship with in-hospital MACEs and the effect of some clinical characteristics on this relationship were not considered. Furthermore, previous studies that were conducted in developed countries with a different quality of care cannot be applied in Iran, as Iran is a developing country and the studies were not performed according to the 24/7 primary PCI service registry.
The objective of this study protocol is to determine the relationship between time to treatment and in-hospital MACEs.
This cross-sectional study will take place at the Tehran Heart Center (THC), which is affiliated with Tehran University of Medical Sciences (TUMS) in Tehran, Iran. Data related to patients with STEMI, who underwent primary PCI between March 2015 and March 2019, that have been prospectively recorded in the THC’s 24/7 primary PCI service registry will be analyzed. The study outcome is the occurrence of in-hospital MACEs. Data analysis will be conducted using SPSS for Windows, version 16.0 (SPSS Inc). We will perform chi-square tests, independent-samples t tests, or the Mann-Whitney U test, as well as univariate and multivariate binary logistic regression with a significance level of less than .05 and 95% CI for odds ratios.
From March 2015 to September 2017, 1586 patients were included in the THC service registry, consecutively. We will conduct a retrospective analysis of this registry on patient entries between March 2015 and March 2019 and data will be analyzed and published by the end of 2019.
To our knowledge, this is the first observational study based on the 24/7 primary PCI service registry in Iran. The findings of this study may reveal current problems regarding time to treatment in STEMI management in the THC. Results from this study may help determine appropriate preventive strategies that need to be applied in order to reduce time-to-treatment delays and improve patients’ outcomes following primary PCI in the setting of STEMI at the THC and similar clinical centers.
DERR1-10.2196/13161
Cardiovascular diseases continue to be a main cause of premature mortality and long-term disability worldwide [
Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy for patients with STEMI [
Although the recent guidelines have emphasized performing reperfusion strategy for patients with STEMI in a timely manner [
Door-to-balloon time of less than 90 minutes has been considered as the maximum target time for primary PCI [
In contrast, despite improvements in door-to-balloon time over the years, several studies demonstrated no improvement in clinical outcomes and survival rates of patients who underwent primary PCI [
Although previous studies indicated no relationship between door-to-balloon time and 1-year MACEs [
Because time to treatment can be important for predicting clinical outcomes, the relationship between time to treatment and 1-month all-cause mortality was assessed by Kim et al in 2017 for the first time [
There is no information on the relationship between time to treatment and in-hospital MACEs among patients with STEMI undergoing primary PCI in Iran. Such information is necessary for health care systems to identify sources of time delays, to help them plan better, and to allow them to apply preventive strategies for improving clinical outcomes following primary PCI in STEMI management. Therefore, this study has been designed to determine the relationship between time to treatment and in-hospital MACEs among patients with STEMI who have undergone primary PCI according to the Tehran Heart Center’s (THC) 24/7 primary PCI service registry in Iran.
This is a cross-sectional study that has been approved by the Institutional Review Board (#9511171022) and the Research Ethics Committee (REC) of Tehran University of Medical Sciences (TUMS), Tehran, Iran, on July 25, 2018 (approval ID: IR.TUMS.MEDICINE.REC.1397.290). This study protocol is based on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement [
The study will take place at the THC affiliated with TUMS. The THC is a “cardiac center of excellence” and provides medical services by full-time specialists and well-trained nursing staff; it is considered one of the best-equipped diagnostic and therapeutic cardiology centers in Iran and in the region. From 2001 to the end of 2017, about 1,300,000 outpatient visits, 280,000 hospitalizations, and 35,000 angioplasties have been recorded for the THC [
Patients of both genders, over 18 years of age, experienced STEMI and received primary PCI within the recommended time interval (ie, 120 minutes from STEMI diagnosis) [
Variables such as demographic and clinical characteristics and study outcome will be used for statistical analysis (see
We will use the THC 24/7 primary PCI service registry as the main data source in our study. The THC joined this service registry in March 2015. At first, it was conducted at the THC as a pilot scheme for several months. Afterward, in September 2015, it was applied as a default treatment strategy for patients with acute STEMI (Third Report of the Databank of the THC, 2017 [internal report]).
The THC 24/7 primary PCI service registry was approved by the REC affiliated with TUMS and informed consent was obtained from all patients for data collection and follow-ups. Data related to patients with STEMI who underwent primary PCI in one of the six catheterization laboratories in the THC were collected prospectively through a STEMI management registry form. Data were collected by trained emergency department nursing staff at admission time, catheterization laboratory nursing staff, and interventional cardiology fellows; data will be entered into the service registry by research staff on a weekly basis. Patients who expired before beginning the procedure were not included in the registry.
The STEMI management registry form, which is completed prospectively, includes data related to patient demographics (eg, name, birth date, identification code, and gender); admission (eg, mode of patient’s transfer, symptom onset time, first medical contact, first electrocardiogram [ECG] in ambulance, and door time); electrocardiographic assessment (eg, infarcted territories, first hospital ECG time, STEMI ECG time, and STEMI ECG verification time); initial reperfusion therapy (eg, transfer to catheterization laboratory, only fibrinolysis, or no reperfusion with reason); procedure in the catheterization laboratory (eg, arrival time, device time, type of intervention performed, infarct-related artery, initial and final Thrombolysis in Myocardial Infarction [TIMI] flow, and stent thrombosis); and additional treatments from symptom onset to coronary intervention (eg, transvenous or external pacemaker, ventilator support, inotropes, intra-aortic balloon pump, left ventricular assistive device, Impella, cardioversion and defibrillator, and cardiopulmonary resuscitation). In this registry, 30-day, 6-month, and 1-year follow-ups for outcome assessment will be conducted by dedicated research staff via phone calls and outpatients’ clinical record review.
As the 24/7 primary PCI service registry has been conducted in the THC since March 2015, there may be a considerable number of patients with missing treatment times. Excluding these patients from the analysis may introduce selection bias. As an additional analysis, we will compare baseline characteristics between excluded and included groups in order to find any discrepancy and evidence of selection bias. Moreover, to minimize the bias, strict control of quality and professional supervision on the service registry will be applied.
We will conduct a retrospective analysis on patient entries in this service registry between March 2015 and March 2019. From March 2015 to September 2017, data related to 1586 patients were recorded in the THC’s 24/7 primary PCI service registry (Third Report of the Databank of the THC, 2017 [internal report]); we expect to reach 2500 patients by March 2019.
Demographic and clinical variables and outcome included in the study.
Variables | Description | Presentation | |
Age | Age in years at time of admission | Mean (SD); <65 years or ≥65 years, n (%) | |
Sex | Male or female gender | Male or female, n (%) | |
Current smoker | Smoking status at time of admission | Yes or no, n (%) | |
Past medical history | Previous myocardial infarction, PCIa, and coronary artery bypass graft surgery | Yes or no, n (%) | |
Comorbidities | Having diabetes mellitus, hypertension, and hyperlipidemia at time of admission based on patient or family self-report | Yes or no, n (%) | |
Family history of cardiovascular diseases | Having family history of cardiovascular diseases based on patient or family self-report | Yes or no, n (%) | |
Emergency medical service user | Transferred to the THCb by emergency medical service | Yes or no, n (%) | |
First medical contact | Emergency medical service arrival time at scene or patient arrival time at emergency department of the THC | Median (IQRc), minutes | |
First ECGd time | Time that first ECG was taken at the THC | Median (IQR), minutes | |
STEMIe ECG time | Time that STEMI was detected on ECG by emergency department staff | Median (IQR), minutes | |
STEMI verification time | Time STEMI was verified by the emergency department physician | Median (IQR), minutes | |
24/7 code time | Time that the 24/7 code was activated at the THC | Median (IQR), minutes | |
Number of diseased vessels | Number of single, double, and triple diseased vessels | Single, double, and triple diseased vessels, n (%) | |
Infarct-related artery | Infarct-related artery | Left coronary artery, left anterior descending artery, left circumflex artery, right coronary artery, or posterior descending artery, n (%) | |
Infarcted territory | Territory of myocardial infarction according to the ECG | Anterior, posterior, inferior, or lateral, n (%) | |
Killip class | Patients’ risk classification for development of heart failure in order to predict mortality | I, II, III, or IV, n (%) | |
Preprimary PCI TIMIf flow | Level of coronary blood flow before primary PCI | 0, 1, 2, or 3, n (%) | |
Postprimary PCI TIMI flow | Level of coronary blood flow following primary PCI | 0, 1, 2, or 3, n (%) | |
Symptom-to-door time | Time from self-reported onset of symptoms to time of hospital arrival | Median (IQR), minutes; |
|
Door-to-balloon time | Time from hospital arrival to time of reperfusion (ie, wire crossing) | Median (IQR), minutes; |
|
Symptom-to-balloon time | Time from self-reported onset of symptoms to time of reperfusion (ie, wire crossing) | Median (IQR), minutes; |
|
Procedural supports | Devices and medications used before, during, and after primary PCI | Pacemaker, mechanical ventilation, intra-aortic balloon pump, inotropes, cardioversion, and defibrillator, n (%) | |
Stent type | Type of stent used during reperfusion | Bare metal stent, drug-eluting stent, or no stent, n (%) | |
In-hospital MACEsg | Composite of myocardial infarctions, stroke, and cardiac death following primary PCI before hospital discharge | Occurrence of MACEs: yes or no; total MACEs, n (%) |
aPCI: percutaneous coronary intervention.
bTHC: Tehran Heart Center.
cIQR: interquartile range.
dECG: electrocardiogram.
eSTEMI: ST-segment elevation myocardial infarction.
fTIMI: Thrombolysis in Myocardial Infarction.
gMACE: major adverse cardiovascular event.
Myocardial infarction: clinical evidence of acute myocardial ischemia and detection of a rise and/or fall of cardiac troponin values with at least one value above the 99th percentile upper limit and at least one of the following:
Symptoms of myocardial ischemia
New ischemic electrocardiogram changes
Development of pathological Q waves [
Stroke: a new focal neurological deficit taking longer than 24 hours and confirmed by imaging [
Target vessel revascularization: either percutaneous coronary intervention or coronary artery bypass graft surgery of the target vessel as the main coronary vessel proximal and distal to the target lesion [
Target lesion revascularization: either percutaneous coronary intervention or coronary artery bypass graft surgery of the target vessel due to restenosis and other complications related to target lesion, which includes the treated segment from 5 mm proximal to the stent to 5 mm distal to the stent [
Cardiac death: any death related to myocardial infarction, cardiac arrhythmia, and heart failure [
We will conduct statistical analysis using the statistical package SPSS for Windows, version 16.0 (SPSS Inc). Categorical variables will be reported as numbers and percentages and will be compared by chi-square test. In order to compare continuous variables, independent-samples
Data from March 2015 to September 2017 related to 1586 patients with STEMI who underwent primary PCI in the THC have been recorded consecutively in the THC service registry. Data analysis of this service registry will be conducted retrospectively on patient entries between March 2015 to March 2019. Data will be analyzed and published by the end of 2019.
As the first study on the 24/7 primary PCI service registry in Iran, it may reveal current problems regarding time to treatment in STEMI management at the THC. To our knowledge, this is the first observational study of the relationship between time to treatment and in-hospital MACEs according to the service registry in Iran. Therefore, the findings of this study may help us detect sources of delays—patient delays, system delays, or both. These findings may assist us in applying appropriate preventive strategies in order to reduce time-to-treatment delays and improve patients’ outcomes following primary PCI in the STEMI setting in the THC and similar clinical centers.
There are some limitations in this study. First, this is a single-center observational study. Thus, no causal relationship between time to treatment and in-hospital MACEs can be proven conclusively. Second, the study population consists of patients with STEMI who were treated with primary PCI. Therefore, the findings cannot be generalized to patients with STEMI who received thrombolytic therapy.
electrocardiogram
Iranian Project for Assessment of Coronary Events 2
interquartile range
Korea Acute Myocardial Infarction Registry
major adverse cardiac event
percutaneous coronary intervention
Research Ethics Committee
ST-segment elevation myocardial infarction
Strengthening the Reporting of Observational Studies in Epidemiology
Tehran Heart Center
Thrombolysis In Myocardial Infarction
Tehran University of Medical Sciences
This study protocol is related to the residency program thesis by Dr Kian Alipasandi in the field of cardiology at the School of Medicine of TUMS, Tehran, Iran. The authors would like to thank the School of Medicine and the THC’s research department for approving this research project.
None declared.
All authors made substantial contributions to the conception, design, and preparation of the primary study protocol draft or to its critical refinement for important intellectual content. In addition, all authors agreed to be accountable for all aspects of the work and approved the final version of this study protocol.