INTRODUCTION
Acute myocardial infarction (AMI) is the leading cause of preventable death in Argentina and in most developing countries. Timely treatment has a positive impact on short-and long-term prognosis. Therefore, it is of utmost importance to understand how treatment patterns and their outcomes evolve in the local population. To this end, various tools allow for the observation of how indicators evolve over successive periods, the evaluation of advances in care, and the identification of barriers and opportunities for improvement. (1)
Prevalent disease registries are effective tools for monitoring clinical care and their outcomes because they are inexpensive and simple to use. There are multiple publications of AMI registries from Europe, the United States, Asia, and Oceania. These publications provide insight into clinical evolution, the effects of treatments, and issues arising from delays in medical interventions. (2-5)
The ARGEN-IAM-ST registry is the only registry on ST-segment elevation MI (STEMI) in Argentina that has been active for more than a decade. In previous publications, the registry has been a reference for understanding the reality of STEMI nationwide. (6-9) It is important to create a timeline for summarizing information for a given period and, at the same time, defining how the most important parameters related to care, treatment, and prognosis have evolved.
OBJECTIVE
The aim of this study is to evaluate mortality associated with STEMI in Argentina over recent years using data from the ARGEN-IAM-ST registry, and to evaluate time to presentation and time to reperfusion.
METHODS
The ARGEN-IAM-ST registry is a prospective, multicenter, and nationwide study with voluntary participation, conducted in collaboration between the Argentine Society of Cardiology and the Argentine Federation of Cardiology. The protocol had been previously published. (6) The target population was made up of STEMI patients admitted within the first 36 hours of the event. Non-STEMI cases, secondary infarctions, aortic dissection, pericarditis, and myocarditis were excluded. Cases registered with a date of chest pain onset between January 1, 2015, and December 31, 2024, were analyzed. Centers that reported at least one case during the specified period were considered participants in the study.
The most relevant data collected included coronary risk factors, cardiovascular history, and comorbidities; clinical picture, treatment used (antiplatelet agents, reperfusion, and treatment at discharge), and in-hospital clinical outcome. Data related to delays until effective treatment was achieved was also obtained.
The following times and delays were considered:
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1) Time to presentation: time elapsed between the onset of symptoms suggestive of myocardial ischemia and first medical contact
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2) Time to reperfusion: time elapsed between arrival at a medical center and initiation of reperfusion treatment.
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a) In case of fibrinolytic therapy:
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Time window: time interval in minutes from the onset of symptoms to the start of infusion.
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Door-to-needle time: time interval in minutes from arrival at the institution to the start of infusion.
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b) In case of percutaneous coronary intervention:
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Time window: time interval in minutes from the onset of symptoms to balloon inflation.
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Door-to-balloon time: time interval in minutes from arrival at the institution to balloon inflation.
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Data were collected on the REDCap platform. The protocol was registered in ClinicalTrials.gov with the number NCT2458885.
Ethical considerations
The protocol design of the ARGEN-IAM-ST registry was approved by the Committee on Ethics of the Argentine Society of Cardiology.
Statistical analysis
Qualitative variables are presented as frequencies and percentages. Quantitative variables are expressed as mean ± standard deviation (SD), or median and interquartile range (IQR), according to their distribution.
A logistic regression analysis was performed to explore mortality during the analyzed periods (which were annual) and to identify statistical differences. A p value < 0.05 was considered statistically significant. The analysis was performed using R statistical package.
RESULTS
A total of 7690 cases were analyzed from 209 institutions; 42% of the participating centers corresponded to public institutions. Mean age was 61.1± 12 years, and 78.8% were male. Fifty-four percent had hypertension, 27.2% had diabetes, 10.8% were active smokers, and 37.5% had dyslipidemia (Table 1). Over the past 10 years, the median time from the onset of chest pain to presentation was 120 minutes (IQR 59-243), door-to-needle time was 55 minutes (IQR 30-120), total ischemic time for fibrinolytic therapy was 180 minutes (IQR 108-300), door-to-balloon time was 79 minutes (IQR 45-137), and total ischemic time for percutaneous coronary intervention was 315 minutes (IQR 190-607). These values did not present significant interannual variations (Table 2).
Table 1.
Baseline characteristics
| Variables | n = 7690 |
|---|---|
| Age (years) | 61.1 ± 12 |
| Male | 6059 (78.8%) |
| Hypertension | 4153 (54.0%) |
| Diabetes mellitus | 2092 (27.2%) |
| Current smoking | 831 (10.8%) |
| Dyslipidemia | 2882 (37.5%) |
| Family history | 1129 (14.7%) |
| Previous coronary artery disease | 955 (12.4%) |
| Previous heart failure | 149 (1.9%) |
| COPD | 232 (3.0%) |
| Chronic kidney disease | 68 (0.9%) |
| Previous atrial fibrillation/atrial flutter | 30 (0.4%) |
| Previous stroke | 111 (1.4%) |
| Peripheral vascular disease | 86 (1.1%) |
Qualitative variables are presented as frequency and percentage and quantitative variables are expressed as mean and standard deviation COPD: chronic obstructive pulmonary disease
Table 2.
Time intervals (in minutes) of the ARGEN-IAM-ST Registry [median (IQR)]
| Year | N | Chest pain to presentation | Door-to needle time | Time window to fibrinolysis | Door-to-balloon time | Time window to PCI |
|---|---|---|---|---|---|---|
| 2015 | 1699 | 130 (60-300) | 49 (30-90) | 165(114-297) | 85 (53-139) | 301(190-570) |
| 2016 | 307 | 90 (40-180) | 45 (30-120) | 185(149-315) | 86 (53-166) | 280 (180-533) |
| 2017 | 688 | 97 (45-190) | 72 (30-131) | 200(124-292) | 88 (50-150) | 300(185-571) |
| 2018 | 911 | 102 (40-240) | 60 (30-129) | 190(120-330) | 75 (40-140) | 323(191-616) |
| 2019 | 1045 | 120 (60-240) | 60 (30-101) | 160 (110-260) | 74 (43-135) | 310(190-600) |
| 2020 | 674 | 120 (59-240) | 61 (40-128) | 180 (107-295) | 74 (38-140) | 315(190-600) |
| 2021 | 688 | 120 (56-270) | 45 (30-177) | 223 (133-328) | 70 (40-120) | 365 (190-695) |
| 2022 | 696 | 120 (60-270) | 52 (30-150) | 200 (120-300) | 82 (45-135) | 335 (203-679) |
| 2023 | 488 | 112 (60-240) | 45 (15-158) | 185 (98-271) | 75 (40-128) | 325(192-559) |
| 2024 | 393 | 100 (48-200) | 40 (29-105) | 150 (90-260) | 70 (38-120) | 322(180-646) |
| Total | 7589 | 120 (59-243) | 55 (30-120) | 180 (108-300) | 79 (45-137) | 315(190-607) |
IQR: interquartile range; PCI: percutaneous coronary intervention
In-hospital mortality was 8.6% over 10 years with no statistically significant variations when comparing annual periods (p = 0.927) Figure 1).Reperfusion therapy was utilized in at least 90% of cases in 8 of the 10 years analyzed, except for 2015 (84.2%) .There were no significant variations in the use of reperfusion therapy or in mortality (Figure 2).
Anterior wall MI was the most common presentation, accounting for 39.7% of cases. Cardiogenic shock was present on admission in 7.4% of patients, 11.5% had cardiopulmonary arrest at the time of presentation, and heart failure was the most common in-hospital complication, occurring in 13.2% of cases. With respect to a key safety indicator, 4.1% of patients experienced bleeding complications during hospitalization.
Table 3.
Characteristics and complications of STEMI
| Characteristic | n=7690 |
|---|---|
| ECG location (n = 7538) | |
| Anterior wall (V1-V6) | 2989 (39.7%) |
| Inferior wall (L1 -LII -VF) | 2828 (37.5%) |
| Lateral wall (L1 and VL or V5-V6 only) | 256 (3.4%) |
| Anterolateral wall | 710 (9.4%) |
| Anterior and inferior wall | 81 (1.1%) |
| Inferolateral wall | 626 (8.3%) |
| Undetermined (LBBB or cannot be located) | 48 (0.6%) |
| Infarct-related artery (n=6407) | |
| LMCA | 85 (1.3%) |
| LAD | 3052 (47.6%) |
| Diagonal | 126 (2.0%) |
| LCx | 830 (13%) |
| RCA | 2201 (34.4%) |
| Venous graft | 33 (0.5%) |
| Arterial graft | 16 (0.2%) |
| None | 47 (0.7%) |
| Unidentified | 17 (0.3%) |
| Killip and Kimball class (n=7533) | |
| KK I | 5798 (77%) |
| KK II | 1068 (14.2%) |
| KK III | 113 (1.5%) |
| KK IV | 554 (7.4%) |
| Bleeding (n=7664) | |
| No bleeding | 7348 (95.9%) |
| Minimal | 191 (2.5%) |
| Minor | 74 (1.0%) |
| Major | 51 (0.7%) |
| Reinfarction | 132 (1.7%) |
| PIA | 160 (2.1%) |
| Cardiogenic shock * | 728 (9.5%) |
| Intraaortic balloon pump | 152 (2.0%) |
| Heart failure | 1015 (13.2%) |
| Atrial fibrillation | 341 (4.4%) |
| Electric cardioversion | 365 (4.7%) |
| Pulmonary artery catheter | 227 (3.0%) |
| Mechanical ventilation | 646 (8.4%) |
| Ischemic stroke | 67 (0.9%) |
Qualitative variables are presented as frequency and percentage and quantitative variables are expressed as mean and standard deviation
COPD: chronic obstructive pulmonary disease
Participating physicians were asked to complete a brief survey about their perceptions of the causes of delayed reperfusion in MI. They reported the following causes: delays in medical consultation (38.4%) delays in referral to another center for percutaneous coronary intervention (20.5%) ; delays in transportation (19.3%) ; and delays in the emergency department (13.5%) (Table 4).
Table 4.
Causes of delays in reperfusion
| Cause of delay | n = 7690 |
|---|---|
| Patient presentation | 2954 (38.4%) |
| Ambulance | 1483 (19.3%) |
| Emergency room care | 1037 (13.5%) |
| Medical error in the diagnosis of infarction | 860 (11.2%) |
| Catheterization laboratory team | 632 (8.2%) |
| Referral to another center for primary PCI | 1577 (20.5%) |
| Cardiac arrest | 184 (2.4%) |
| Administrative error | 296 (3.8%) |
| First ECG inconclusive | 264 (3.4%) |
PCI: percutaneous coronary intervention; ECG: electrocardiogram
DISCUSSION
This study presents data from 10 years of uninterrupted activity of the ARGEN-IAM-ST registry. This is the longest-running study on STEMI in Argentina. Despite the voluntary nature of registry participation and the absence of funding for on-site auditing and sampling planning, the registry has been widely accepted by institutions, with 42% being public hospitals and 58% being private institutions or managed by social security funds. Since its inception, subsequent papers have been published on the reality of STEMI. In this publication, a timeline is presented to offer an overview of the most important aspects regarding STEMI care and outcomes, such as time to presentation, time to treatment, time to reperfusion, and overall in-hospital mortality. These are important indicators that help evaluate the management of STEMI cases. (6-9) Although the number of participating centers and the number of cases entered into the registry have declined over time, as seen in Table 2 (1699 cases in 2015 and 393 cases in 2024), there have been no significant variations in the most important indicators. This suggests that the decline in cases did not affect these indicators, possibly because the centers contributing the most records have remained constant over time.
Despite the high volume of cases achieving reperfusion, we have not observed a variation in in-hospital mortality. This is noteworthy because mortality is higher than in other registries, such as that of the European Society of Cardiology, where the 30-day mortality rate is 4.4% . The highest mortality rate was observed in Middle Eastern centers, which are not affiliated with the Society (5.9%) . (5) In the ACI-SEC Infarction Code Registry conducted in Spain in 2019, Oriol Rodriguez-Leor et al. analyzed data from 5401 patients, reporting in-hospital mortality and 30-day mortality rates of 5.5% and 7.9% respectively. The reperfusion therapy rate was 91.9% and reperfusion was performed within 120 minutes of the first medical contact in more than half of these cases. (21) In our registry, despite times to fibrinolytic therapy or percutaneous coronary intervention being shorter, in-hospital mortality was higher. This could be explained by the fact that the time to presentation was 50% longer compared to the Spanish registry. In the ACI-SEC Infarction Code Registry, the median time to presentation was 60 minutes. In the ARGEN-IAM-ST Registry, the lowest median time to presentation was 90 minutes in 2016 and the overall median time doubled after 10 years of follow-up. This contributes to an extended total ischemic time, a crucial indicator that may be associated with this excess mortality.
Amini et al. investigated the trend in cardiovascular disease mortality from 1990 to 2017 and concluded that, with a few exceptions, there was an overall downward trend. (11) Conversely, the prevalence and incidence of cardiovascular disease are increasing globally, as evidenced by the publication by Khan et al., who also explored the period between 1990 and 2017 as a reference. This suggests that despite the rise in the prevalence and incidence of cardiovascular disease, different health systems have found ways to effectively treat this significant challenge. (12)
Over the past decade, there has been no significant progress in care times. When professionals were asked about this issue, their response was that they perceive delays in time to presentation, time to referral to another center, and in ambulance arrival as the main barriers to improving reperfusion times. This has been a recurring issue in previous publications by the ARGEN-IAM-ST group, yet the issue remains unresolved. (6,7)
The most significant complication that occurred during hospitalization was heart failure, with an incidence of 13.2% compared to 7.4% with cardiogenic shock and 11.5% with cardiac arrest on presentation. The incidence of heart failure during hospitalization is higher than in other registries. For example, the GRACE registry reported a rate of 5.6% in 13 707 cases, Spencer et al. recorded a rate of 8.6% in 123,938 patients, and the US ACTION registry reported a rate of 3.6% . (13-15) Given that heart failure rates in this registry are more than double those in other registries, the prolonged total ischemic time could be the cause of this phenomenon despite the high reperfusion rates, as it was previously mentioned. (16)
The most significant indicators show an impact on in-hospital morbidity and mortality. As is well known, these indicators also suggest that the impact will occur during mid-and long-term follow-up, particularly for patients who develop heart failure. (17-20)
This exploratory analysis shows prolonged times to presentation, which is consistent with physicians' perceptions. Issues related to the organization of resources (delays in referral, ambulance arrival, and emergency care) are also reported. It is widely recognized that the logistics of transfers can lead to delays in reperfusion times. Therefore, the implementation of effective strategies in both prehospital and hospital settings is strongly recommended. (21)
Based on this information, it is necessary to educate and promote awareness among the population to prevent delays in cases of chest pain. Additionally, health systems must be organized to prevent delays in care and optimize human and technological resources. Implementing protocols and creating networks for AMI care could improve current outcomes and avoid another decade of stagnation. This approach would avoid the economic and social impacts of being left behind by the improvements seen in other health systems.
In the case of Argentina, a country with a fragmented health system and different districts with their own demographic, geographic, and climatic characteristics, it is imperative to develop policies tailored to each reality.
CONCLUSION
Over the past 10 years, the ARGEN IAM-ST registry shows absence of significant changes in STEMI mortality despite high reperfusion rates. This could be due to prolonged times to presentation and treatment, which have not shown significant reductions. Analysis of delays suggests that logistics could be improved. It is imperative to implement policies designed to change the reality of AMI in Argentina to reduce the time between symptom onset and patient presentation, improve medical care, and optimize referral logistics. This will optimize both public and private healthcare resources.
Study limitations
The ARGEN IAM-ST registry is a voluntary registry, with no financial incentives and no data auditing at each institution. Data quality control is performed through the REDCap platform. The contribution of researchers and participating institutions is vital to the project's sustainability. This registry model may be subject to reporting bias and does not have a sampling strategy.