Characteristics of patients with acute myocardial infarction contacting primary healthcare before hospitalisation: a cross-sectional study

About 1–3% of primary healthcare (PHC) patients experience chest pain [1, 2]. Chest pain can have many different causes; most of them are of non-cardiac origin. In 10–18% of cases, the chest pain is caused by ischaemic heart disease, of which 2–4% as the result of myocardial infarction (MI) or unstable angina [3‐5], conditions that require immediate attention. In some countries, general practitioners (GP) play a major role in the early care of acute MI and are often the first to be contacted by patients [6]. In most settings, however, consultation with a GP, instead of a direct call to the emergency medical services (EMS), increases pre-hospital delay [4, 7, 8]. Many cases of sudden cardiac death occur outside a hospital. Therefore, prompt action when patients experience symptoms indicating acute cardiac ischemia is of great importance [7].

According to existing European clinical guidelines on cardiovascular disease prevention, the GP should evaluate the risk factors and clinical findings when a patient contacts PHC with chest pain, and decide if the patient should be transferred to hospital [9]. However, the low prevalence of acute MI can make the diagnosis difficult [10], particularly because the medical history, symptom presentation, and findings from an electrocardiogram (ECG) are not always indicative [11, 12].

A great deal of knowledge exists today about the reasons for patient [13, 14], as well as system, delay [15]. Similarly, studies have consistently reported that only half of the patients with MI use the EMS [16, 17]. Factors associated with underutilisation of the EMS have previously been explored [18, 19]. However, the reasons for contacting the PHC for symptoms suggestive of acute MI, as a contributory factor to prolonged pre-hospital delay, have not yet been examined.

Therefore, the aims of this study were to 1) describe background characteristics, symptoms, actions and delay times in patients contacting the PHC before hospitalisation when falling ill with an acute MI, 2) compare those patients with acute MI patients not contacting the PHC, and 3) explore factors associated with a PHC contact in acute MI patients.

The main observation of this study was that one in five people contacted PHC when experiencing symptoms suggestive of an acute MI, and this was more common in patients later diagnosed with NSTEMI. Fluctuating symptoms were predicative for PHC contact and onset of symptoms out of hours predicted other contacts than PHC. Furthermore, the PHC patients had a considerably longer delay time from symptom onset to decision to seek medical care with a median difference of 1:35 hours. A contact with the PHC also impacted on the total delay from symptom onset to diagnosis in STEMI patients. This is in line with another Swedish study that reported that patients with MI are delayed to hospital admission when they contact the PHC in the pre-hospital phase [23]. A rapid recognition and transportation of all patients with MI is crucial for their treatment. This has been well proven for STEMI, but patients with NSTEMI also benefit from reduced delay [24‐26]. However, 20% of those contacting the PHC in our study did not arrive by ambulance to the hospital. For these reasons, triage of patients with chest pain is imperative. In addition to the existing clinical European guidelines on cardiovascular prevention in PHC [9], GPs are in need of validated diagnostic tools to help distinguish patients with chest pain for referral to the ED, particularly since the medical history, symptom presentation, and findings from the ECG are not always indicative [11, 27]. The use of troponin testing - a biomarker used to assess myocardial injury - may reduce emergency referrals but probably at the cost of an increased risk of overdiagnoses, especially among older patients with acute MI and often chronically increased troponin levels [2], and is therefore not encouraged in GP offices [28, 29]. However, a more in-depth medical history, detailed symptom assessment and physical examination using a clinical prediction score could possibly assist the GP to rule out coronary heart disease in PHC patients with chest pain [30, 31]. A previous study has shown that older age, male gender and a history of MI are useful predictors of ischaemic heart disease when evaluating patients with chest pain [32]. Likewise, the presence of IHD risk factors (i.e., diabetes, smoking, hyperlipidaemia) should also lead to an increased suspicion of acute cardiac ischemia, when evaluating patients with chest pain [9].

In our study, most patients contacting PHC had cardinal symptoms of MI, and no symptom was independently associated with PHC contact. Thus, symptoms do not discriminate MI patients taking contact with PHC from other MI patients. On the other hand, was symptoms waxing and waning strongly associated with PHC contact. Accordingly, a patient with cardinal MI symptoms but whose symptoms have not been constant but have instead been coming and going ought to lead to suspicion from the GP that this may be an acute MI. However, up to 80% of patients consulting a GP with chest pain have a non-cardiac diagnosis and do not need referral to the ED. Referral of all these patients would result in overcrowding of the ED [3]. Consequently, more studies are needed to discriminate factors between cardiac and non-cardiac chest pain.

We found that approximately half of the patients who contacted PHC did not consider themselves sick enough to contact the EMS. This finding is important since active care of patients with MI starts in the ambulance and the decision to claim expensive but necessary resources for transportation needs to be strengthened. Patient delay is the longest in the pre-hospital chain and a difficult aspect to modify, as previous public campaigns have shown [33], although a more recent mass media campaign in Australia demonstrated that an awareness of the campaign was significantly associated with shorter delay times [34]. Studies focusing on individual education programmes have been more successful than mass media campaigns [33, 35]. These interventions should take into account the complexity of translating knowledge into actions and tailor their message according to target groups. GPs are an important part of these pre-hospital interventions, since many patients with chest pain contact PHC. Clinicians should individualise their approach when educating patients with an increased risk of MI, such as those with hypertension, diabetes and hypercholesterolemia, and address relevant issues such as the various presentations of MI and the importance of a timely response to these symptoms [36]. Still, whatever we as clinicians do or say, some people will contact their PHC for symptoms suggestive of an acute MI, not because they are ignorant or unaware of the importance of a short delay, but just because it seems the right thing for them to do. And when they do contact the PHC, we need to respond constructively.

A substantial part of the patients contacts their PHC before they are diagnosed with MI, although experiencing cardinal symptoms such as chest pain and ambulance services are still underutilized in acute MI patients. There is need for better knowledge in the population about symptoms of MI and adequate pathways to qualified care. Knowledge and awareness amongst primary healthcare professional´s on the occurrence of MI patients is imperative.