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Original article

Pre-hospital care-seeking in patients with acute myocardial infarction and subsequent quality of care in Beijing

SONG, Li; YAN, Hong-bing; HU, Da-yi; YANG, Jin-gang; SUN, Yi-hong

Editor(s): WANG, Mou-yue

Author Information
doi: 10.3760/cma.j.issn.0366-6999.2010.06.005
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Abstract

Cumulative evidence has demonstrated that primary percutaneous coronary intervention (PCI) is the optimal reperfusion strategy for ST-elevation myocardial infarction (STEMI) if performed in a timely manner by experienced operators.1,2 However, availability of this strategy is limited because only 12.3% of hospitals of all tiers in Beijing performed primary PCI in 2006. Patients who are diagnosed with acute myocardial infarction (AMI) at a neighborhood small community hospital are usually referred to a large hospital that can perform PCI and continuous cardiac monitoring, thus increasing the delay time to reperfusion.3,4 Up to now, no data are available regarding care-seeking pathway and subsequent treatments in patients experiencing symptoms of AMI in Beijing. Therefore, this study was conducted to evaluate the pre-hospital care-seeking pathway and subsequent quality of care in patients with STEMI in the Beijing health care system, which offers patients a choice between seeking care in a neighborhood small community hospital or a large hospital with a cardiac catheterization laboratory.

METHODS

Patients and settings

This cross-sectional and multicenter survey was conducted between January 1 and December 31, 2006. The patients comprised consecutive STEMI patients who were admitted to 11 hospitals qualified as tertiary centers in Beijing. All these hospitals were capable of performing reperfusion therapies including thrombolysis and primary PCI 24 hours a day. Patients meeting the following criteria were included in the study: (1) ST-segment elevation >0.1 mV in ≥2 contiguous precordial leads or adjacent limb leads or new left bundle branch block; (2) elevated serum cardiac biomarkers; and (3) admission within 24 hours of symptom onset. Patients were excluded because (1) their clinical condition did not permit them to be interviewed (such as unstable hemodynamics and coma); (2) they had communication problems (serious hearing and cognitive impairments); (3) they were transferred from outside Beijing; or (4) they refused to participate in the investigation. Patients were categorized into the following 2 groups: SH group (first seeking care in a neighborhood small community hospital) and LH group (seeking care directly in a large hospital with a cardiac catheterization laboratory).

Data collection

Data were collected through structured interviews and reviewing of medical records. A questionnaire was designed to obtain the following information: (1) demographics: age, gender, education level (≥ college or < college), monthly income (≥2000 or <2000 RMB yuan (being equivalent to approximately 293 USD)) and health insurance coverage; (2) situational factors: time and place of symptom onset, presence of a bystander, self-treatment approaches, and consulting a doctor before seeking care; (3) symptoms: severity of symptoms (bearable or unbearable), location and duration of pain or discomfort, and other associated symptoms, such as nausea, vomiting, perspiration, dyspnea, etc; (4) symptoms interpretation (cardiac origin or others); (5) time interval from symptom onset to hospital arrival; and (6) mode of transport. All patients were interviewed by trained investigators within 7 days after admission.

Medical records were used to obtain the following information: (1) cardiovascular risk factors including hypertension, diabetes, dyslipidemia, body mass index (BMI), and a family history of coronary artery disease (CAD); (2) previous medical history, such as CAD, myocardial infarction, heart failure, and stroke; (3) clinical parameters at admission: Killip class, ECG, and hemodynamics including heart rate, systolic blood pressures, and diastolic blood pressures; and (4) major cardiovascular events during hospitalization including reinfarction, serious bleeding, stroke, heart failure, severe arrhythmias such as ventricular tachycardia, ventricular fibrillation, atrial fibrillation, II degree II type atrioventricular block, complete atrioventricular block, and death. In addition, early reperfusion procedures were carefully specified (thrombolysis or primary PCI) and analyzed. Several time interval parameters were evaluated: time interval from symptom onset to arrival at one of the 11 study hospitals (i.e., total pre-hospital delay), time interval from hospital arrival to the initiation of thrombolysis (i.e., door-to-needle), and time interval from hospital arrival to the first balloon inflation (i.e., door-to-balloon).

Ethical considerations

The study protocol was approved by the human research ethics committee at the Peking University People’s Hospital and consistent with the Declaration of Helsinki. The study was explained to each patient and their family members, and a written informed consent was obtained.

Statistical analysis

Categorical data are expressed as numbers and percentages, continuous data as mean ± standard deviation (SD), and time intervals as medians and interquartile ranges. The chi-square test was used to analyze the categorical data, unpaired Student’s t test was used to analyze the continuous variables, and the Mann-whitney U test was used to analyze the medians. A multivariable Logistic regression was performed to identify the predictors of small hospital visit using variables showing marginal association with P <0.10 according to univariate analysis. Another multivariate Logistic regression was performed to see whether seeking care at a small hospital was an independent predictor of not receiving reperfusion therapy after review of demographic factors (age and gender) and histories of diseases (diabetes, hypertension, and CAD). Odds ratio (OR) and 95% confidence interval (CI) were calculated. Data were analyzed using the SPSS 11.5 software. All significant tests were 2-sided, and P <0.05 was considered statistically significant.

RESULTS

Sample characteristics

During the period of the study, a total of 566 patients were eligible for analysis. Of these patients, 78.4% were male, with a mean age of (61±13) years. One hundred and sixty (28.3%) patients first arrived at a small community hospital and were transferred to a large hospital with a cardiac catheterization laboratory (SH group); the remaining 406 (71.7%) patients were admitted directly to large hospitals (LH group). The baseline characteristics of the sample and those of the 2 groups are summarized in Table 1.

Table 1
Table 1:
Comparison of the baseline characteristics of the SH and LH groups

Predictors of small hospital visits

Patients who first arrived at a small community hospital were less likely to have a college education (13.9% vs. 23.4%, P=0.011), higher income level (≥2000 RMB yuan per month, 22.5% vs. 33.3%, P=0.015) and health insurance coverage (69.4% vs. 82.5%, P=0.001) than those in the LH group. However, patients who attempted self-treatment (58.9% vs. 45.0%, P=0.004) and consulted a doctor before seeking care (3.7% vs. 0, P=0.008) were more likely to choose a large hospital. Also, patients with a history of CAD (P=0.008) or myocardial infarction (P=0.009) were admitted more frequently to a large hospital. Regarding the influence of cognitive factor, patients who interpreted their symptoms to cardiac origin were more likely to choose a large hospital (67.0% vs. 53.8%, P <0.001) than those who interpreted their symptoms to non-cardiac origin. In addition, patients in the LH group presented with more serious arrhythmias at admission than those in the SH group (11.8% vs. 5.0%, P <0.001).

Multivariate analysis showed that interpreting symptoms to non-cardiac origin (OR, 1.996; 95% CI: 1.264-3.155, P=0.002), absence of a history of myocardial infarction (OR, 1.595; 95% CI: 1.086-3.347, P=0.021), non-health insurance coverage (OR, 1.931; 95% CI: 1.079-3.012, P=0.046) and absence of sense of impending doom (OR, 4.367; 95% CI: 1.279-14.925, P=0.021) were independent predictors of small hospital visit.

Comparison of pre-hospital delay between the two groups

Patients in the LH group had a significantly shorter total pre-hospital delay time than those in the SH group (medians, 245 vs. 116 minutes, P <0.001). We did not collect data on the time of arrival at and departure from small community hospitals.

In the SH group, the most common modes of transportation to small hospitals were taxi (34.4%) and private car (30.0%), approximately 21.9% of the patients called the emergency medical system (EMS). Additionally, 6.9% of the patients in this group arrived on foot, 1.9% by bicycle, 2.5% by public transport, and 2.5% by other means. The most common mode of transportation was ambulance (80%) when they were transferred to large hospitals. However, there were still 20% of the patients relied on other means.

In the LH group, approximately 38.4% of the patients called the EMS. Additionally, 36.2% of the patients arrived by taxi, 22.4% by private car, and 3.0% on foot.

Comparison of early reperfusion therapies between the two groups

In the SH group, 11.9% (n=19) of the patients received thrombolysis in small hospitals before transfer.

In total, 456 (80.6%) patients received early reperfusion therapies in the 11 hospitals, more precisely, 94 (16.6%) received thrombolysis, and 362 (64.0%) underwent primary PCI (not including those with facilitated or rescue PCI (4.0%)). The LH group had a greater rate of early reperfusion (83.5% vs. 73.1%, P=0.007), mainly because of a greater rate of primary PCI (67.8% vs. 54.4%, P=0.004). After adjusting for demographics and medical history, the patients in the SH group were 1.698 times (95% CI: 1.182-3.661) less likely to receive primary PCI compared with those in the LH group.

The time from symptom onset to needle (medians, 216 vs. 266 minutes, P=0.042) and from symptom onset to balloon (medians, 260 vs. 400 minutes, P <0.001) was significantly shorter in the LH group than in the SH group. However, the difference of time from door to needle (medians, 101 vs. 80 minutes, P=0.298) and from door to balloon (medians, 132 vs. 135 minutes, P=0.357) was not significantly different between the 2 groups (Table 2).

Table 2
Table 2:
Comparison of early reperfusion therapies and time intervals between the 2 groups

DISCUSSION

The major findings in this study are as follows: (1) above one fourth of the STEMI patients in Beijing experienced inter-hospital transfer; (2) several factors including symptoms interpretation, symptoms, history of AMI and insurance coverage influenced the patients’ pre-hospital care-seeking pathway; and (3) the patients who were transferred had longer pre-hospital delays and were less likely to receive primary PCI.

The time from the onset of symptoms of AMI to hospital presentation has long been observed to correlate with in-hospital and long-term mortality. 5Reperfusion therapy can significantly reduce the morbidity and mortality of AMI; however its benefit is highly dependent on the time between the onset of symptoms and the start of reperfusion therapy.6-11 In the United States, median pre-hospital delay ranges from 1.5 to 6.0 hours.12,13 The average patient with STEMI does not seek medical care for approximately 2 hours after symptom onset, and this pattern appears to be unchanged over the last decade.14,15 Experimental and clinical studies have shown that most of the irreversible damage to the myocardium occurs during the first two hours after coronary occlusion. Milavetz et al16 demonstrated that successful reperfusion therapy within two hours was associated with the greatest degree of myocardial salvage. In our study, the median pre-hospital delay of the STEMI patients in the LH group was nearly 2 hours, which was similar to the pre-hospital delay time documented in the GRACE study.17 However, the median total pre-hospital delay in the SH group was two times greater than in the LH group and four times longer than 1 hour recommended by guidelines.

In recent years, primary PCI has become the preferred reperfusion strategy for STEMI patients in Beijing. In our study, 64% of the patients received primary PCI. The patients in the SH group were significantly less likely to receive primary PCI compared with those in the LH group. One of the reasons may be longer pre-hospital delay in the SH group. These results suggest that significant barriers to timely treatment of AMI exist in the current Beijing health care system. According to the 2006 statistics, there are a total of 431 hospitals of all tiers in Beijing; among them 223 are categorized as small hospitals (<100 beds). A small hospital is often closer to a patient’s home. Therefore, it is convenient for patients who are experiencing cardiac symptoms to access a small hospital rather than seek care at a large hospital. Although a large network of neighborhood small hospitals is appropriate and cost effective for people with chronic illnesses or with non-life threatening illnesses, it significantly contributes to pre-hospital delay and reduces the effectiveness of reperfusion therapy.

Public campaigns to promote early access to treatment during AMI have not been particularly effective. For example, the REACT study18 did not find public education to be effective in reducing pre-hospital delay. However, the investigators found an increased use of the emergency medical service (EMS) in individuals who had been exposed to public education. Given the prolonged pre-hospital delay and a certain percentage of small hospital visits in this study in Beijing, we do believe that enhancing public knowledge about signs and symptoms of AMI and how to respond to AMI (e.g. calling the EMS and not visiting a small hospital or clinic) may reduce total pre-hospital delay.

Calling for an ambulance is the recommended response for patients with AMI in China as it is in other countries. In addition to providing defibrillation, emergency drugs, and quick transportation to the correct hospital, the use of ambulance is associated with wider and quicker receipt of initial reperfusion therapies.19-22 Unfortunately, our study showed that only about one third of the STEMI patients in the LH group were transported by ambulance. Although it is beyond the scope of this study, one should note that about 21% of the patients in the SH group arrived at small hospitals by ambulance. This finding suggests the need that ambulance personnel should be properly trained and aware that the patients with suspected AMI should be transported directly to the correct hospital with skilled reperfusion therapies. We also found that, although the most common mode of transportation was ambulance when the patients in the SH group were transferred to large hospitals, there were still 20% of the patients relied on other means.

Under the current Beijing health care system, health care providers in small hospitals also play a pivotal role in reducing pre-hospital delay in patients who first seek medical treatment at a small hospital. In this study, more than one fourth of the STEMI patients first sought medical care in a small hospital that did not provide PCI therapy. Therefore, education of physicians who work in small hospitals should focus on the importance of triaging and referring cardiac patients immediately to a hospital with a catheterization laboratory by ambulance. Furthermore, in order to transfer patients in a safe and timely manner from a small hospital to a large hospital, rapid risk stratification protocols and guidelines for treatment need to be established in the health care system in Beijing that emphasize early thrombolysis or transfer to a PCI center with experienced staff and high-volume interventional operators. The concept of a centralized AMI care network is an important potential strategy to further reduce the morbidity and mortality for patients presenting with AMI. Such networks have been shown to be effective in Europe in reducing door-to-needle time and symptoms-to-reperfusion time and, consequently, in reducing mortality.23

There are several limitations of this study that require mentioning. First, it is a cross-sectional observational study. Second, information collected during the interview relied on the recall of events by the patients. However, in order to minimize the recall bias, the interview was conducted within a week upon admission. Third, we did not collect data on pre-hospital delay time from symptom onset to arrival at a small hospital and from a small hospital to the study hospital respectively. Finally, the sample only represented hospitalized STEMI patients who were admitted in the 11 tertiary hospitals in Beijing within 24 hours at onset of symptoms. Thus, caution should be taken in generalizing our results to entire AMI patients in Beijing.

In conclusion, more than one fourth of the STEMI patients in Beijing experienced inter-hospital transfer. Several factors including symptoms interpretation, symptoms, history of myocardial infarction and insurance coverage were associated with the patients’ pre-hospital care-seeking pathway. The patients who were transferred had longer pre-hospital delays and were less likely to receive primary PCI. Findings support the need for public education in Beijing that focuses on the appropriate response to AMI symptoms. Moreover, regional AMI networks need to be instituted to provide early transfer for PCI from small community hospitals to tertiary centers.

Acknowledgement:

We greatly thank the directors and staff of the 11 participating hospitals for their cooperation in the survey.

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Keywords:

acute myocardial infarction; care-seeking; pre-hospital delay; percutaneous coronary intervention

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