Primary percutaneous coronary intervention (PCI) is the safest strategy for the treatment of ST-segment elevation myocardial infarction (STEMI).¹ According to the Brazilian Society of Cardiology (SBC) and the American Heart Association guidelines, the time from arrival at the initial hospital to the time of the first balloon inflation during primary PCI, defined as door-to-balloon time, should be within 90 minutes.²

In Brazil, adherence to health care guidelines by healthcare centers is still lower than expected,³ resulting in a suboptimal performance of these services, compromising the quality of care and safety of patients.^2,4 Current scientific evidence indicates that adherence to good clinical practice guidelines leads to better performance, reducing morbidity and mortality, length of hospital stay, and costs with STEMI patients, in addition to improve patients’ safety and satisfaction.^5-7

Door-to-balloon time has been used worldwide as an indicator of quality of care, helping to monitor the achievement of aims and goals of health care,^3-5 foster the strengthening of analytical capacity of the teams involved in the management of patients with STEMI and make it as close to ideal as possible.⁸

Therefore, the present study aimed to measure door-to-balloon time and correlate it to the number of deaths and length of hospital stay. We also evaluated whether time intervals of the door-to-balloon time influence on delayed primary reperfusion (wire crossing) at the emergency department of a cardiology hospital in the State of Pará, Brazil.

This was a cross sectional cohort study based on review of medical records. Patients of both sexes, aged ≥ 18 years, with confirmed diagnosis of STEMI were included. All patients had undergone reperfusion within 12 hours after precordial pain and were hospitalized at the emergency department of Gaspar Viana General Hospital Foundation (FHCGV) between May and December 2017. The HCGV is a referral center for heart disease in Pará, Brazil, and the only public hospital for medium and highly complex heart diseases, heading the health care line of myocardial infarction patients among the 144 cities of the state. A total of 109 patients were included in the study.

The following data and variables were systematically collected: age, sex, ethnicity, geographic origin, risk factors, length of hospital stay, number of deaths, and door-to-balloon time and its components.

Since May 2017, to monitor the quality of care provided to STEMI patients in FHCGV, door-to-balloon time and its component times have been prospectively measured using a checklist completed by the staff. The following times were measured: door-to-ECG time (Δt1), time between the electrocardiography test (ECG) and activation of an interventional cardiologist (Δt2) (ECG-to-activation time), time for patient preparation (activation-to-patient preparation) (Δt3), time between patient preparation and beginning of reperfusion (Δt4), time between beginning of reperfusion and balloon inflation (Δt5), time between activation and arrival of an interventional cardiologist at the cath laboratory (Δt6) (Figure 1).

Figure 1

Data collection was conducted after the study was approved by the Ethics Committee of the FHCGV (approval number 2.527.630).

In the present study, most patients with STEMI were male. According to current evidence, cardiovascular diseases are more prevalent in men than women.^1,3In addition, men tend to seek medical care less often than women, due to greater difficulty in identifying and facing possible health problems, in accepting changes in lifestyle and talking about problems. Therefore, in general, instead of seeking preventive medical services, men go to the doctor when disease is already established and there is little chance of recovery, leading to irreversible changes in health and quality of life.^9,10

Age of the study population ranged from 60 to 69 years, with mean of 61 ± 10.88 years. Studies have shown that this is the age range of patients who suffer an acute myocardial infarction, due to development of atherosclerotic plaque on the coronary artery wall. Development of early fibroatheroma starts in adolescence and second decade of life and continues throughout life. Advanced atheroma occurs in individuals older than 55 years of age. At this stage, a thin fibrous cap, formed by the activity of proteolytic enzymes, may rupture, exposing the thrombogenic arterial wall, leading to thrombosis.¹¹

Hypertension, smoking, alcohol consumption and diabetes mellitus were identified as risk factors for acute myocardial infarction. This is in line with the results reported by a regional study by Costa,¹² showing that 71.6% of patients with acute myocardial infarction had hypertension, 71.5% were smokers or ex-smokers, and 45.5% had diabetes mellitus. Also, in a nationwide study on STEMI patients by Wang et al.,³ the main modifiable risk factors identified were hypertension (78.8%), dyslipidemia (57.9%) and diabetes mellitus (37.5%), among others.

Modifiable risk factors such as systemic arterial hypertension, diabetes mellitus, smoking habit, dyslipidemia, obesity, alcohol consumption and psychosocial distress are more common in individuals with lower socioeconomic status; among the indicators of socioeconomic status, educational attainment is the one with the best correlation with the frequency and severity of cardiovascular risk factors.¹³

Door-to-balloon time was longer than the recommended (90 minutes) in 62.4% of the cases. In a multicenter study conducted in public and private hospitals in Brazil, Wang et al.,³ found that 64.04% of 633 patients with STEMI showed a door-to-balloon time longer than 90 minutes. Dharma et al.,¹⁴ in a study carried out in Jakarta, Indonesia, reported that 51.3% of 263 STEMI patients had an inadequate door-to-balloon time. These findings emphasize the difficulty in achieving a satisfactory door-to-balloon time in the management of STEMI patients.

More successful results in door-to-balloon time were detected in studies performed in centers where this parameter has been studied for a longer time, as in the United States, Europe and Asia.^5,15,16 More challenging targets such as a door-to-balloon time shorter than 60 minutes¹⁷were achieved by some authors such as Mentias et al.,¹⁸ who reported a median door-to-balloon time of 38 minutes.

Different from other Brazilian studies,^4,11 the present study did not show the relationship of door-to-balloon with length of hospital stay and mortality rate. For example, Moreira et al.,⁴ investigated the correlation of hospital costs and other variables with the door-to-balloon time (n=141 patients) and did not find any significant difference in the mean length of hospital stay or clinical outcomes between the groups with a door-to-balloon time longer than 90 minutes and those with a door-to-balloon time shorter than 90 minutes. Santos et al.,¹⁹ evaluated the quality of care provided to patients with acute coronary syndrome (ACS) at the emergency department and did not find an association between the quality indicators for ACS (including the door-to-balloon time), and occurrence of complications or death. However, different findings have been reported in international studies, indicating that a reduction in the door-to-balloon time reduces the length of hospital stay, the risk of in-hospital mortality, and even post-discharge mortality at 30 days, one year and three years.^{7,16,18,20,21}

Regarding other component times of the door-to-balloon time that may have influenced the primary outcome, door-to-ECG time (Δt1) and ECG-to-activation time (Δt2) showed a significant correlation (p<0.001) with door-to-balloon time. These two intervals represent the first in-hospital stages of care provided to STEMI patients, and in our sample, they contributed to the delay in primary mechanical reperfusion. Some studies have pointed out that delays in emergency services are associated with difficulties related to the staff, equipment and facility, impaired communication in the hospital setting, and lack of priority care.^5,8,22

Campos et al.,⁵ showed a reduction in door-to-balloon time from 144 minutes to 70 minutes after implementation of a communication code, a 24-hor screening protocol and presence of a cardiologist at the emergency department of the hospital. Also, pre-hospital electrocardiogram, improvement in the communication between the emergency staff and interventional cardiologists and use of technology in patient data transmission, early activation and direct transfer to the cath laboratory result in a significant reduction in the door-to-balloon time.^23-26

This study put the time-to-door time on view; however, its limitation was the fact that it was a one-center study, which limits the generalization of the results.

In our study, door-to-balloon time in the management of STEMI patients was longer than recommended. We did not find a correlation of the door-to-balloon time with the length of hospital stay or in-hospital mortality rate. Door-to-ECG time and ECG-to-activation of a cardiologist contributed to a delay in mechanical reperfusion. These findings indicate the need for monitoring the time components of the door-to-balloon time in the management of STEMI patients in order to reduce the obstacles to a timely coronary intervention by PCI. In this way, proper measures can be implemented to achieve an adequate door-to-balloon time, according to current guidelines on STEMI, thereby promoting a high quality of care to these patients.

Table 3

Components of the door-to-balloon time	Spearman correlation coefficient	p-value*
Door-to-ECG time (Δt1)	0.535	< 0.001
ECG-to-activation time (Δt2)	0.521	< 0.001
Activation-to-patient preparation time (Δt3)	-0.005	0.961
Patient preparation-to-PCI initiation time (Δt4)	0.130	0.209
PCI initiation-to-balloon time (Δt5)	0.168	0.103
Activation-to-arrival of the interventional cardiologist (Δt6)	0.085	0.385

Source: Statistical database of the Cardiology Department of Gaspar Viana General Hospital Foundation between May and December 2017. PCI: percutaneous coronary intervention; * Spearman correlation