Diagnostic value of signs, symptoms and Heart-type Fatty Acid-Binding Protein (H-FABP) in evaluating patients presenting with symptoms possibly matching acute coronary syndrome in primary care

Thoracic complaints in general practice are only in a minority of cases of
cardiac origin but to excluse cardiac origin during first presentation of
symptoms is challenging. This causes significant referral of patients to
coronary care units, where in the end, cardiac analysis turns out to be
negative. On the other hand, because not all patients can reasonably be
referred when suspicion of a cardiac cause is low, a cardiac cause of
complaints can be missed

To determine the added value of signs, symptoms and H-FABP measurement in in-
or excluding acute coronary syndrome in patients with thoracic complaints in
general practice

Eligible patients will be asked by the GP to participate. Diagnostic assessment
during the initial consultation with the GP will take place with standardized
history taking and physical examination, to be documented by the GP on the
standardized case report form (appendix 1 included with this study protocol).
Additionally, patient delay (time between onset of symptoms and contacting the
GP office) and GP delay (time between initial (phone) contact to GP's office
and physical presentation of patient to GP) are recorded. When available,
electrocardiography is performed and a copy of the ECG is added to the case
report form. Diagnostic interpretation can be done following the Dutch
guideline on ACS, which GPs are familiar with6.

The decision by the GP whether or not referral to the cardiologist will take
place will be based on information obtained by history taking, physical
examination and, when available and relevant, ECG only. The GP will be asked to
decide whether or not to refer to a cardiologist and fill out this decision
together with the presumptive diagnosis (e.g. ACS, pyrosis due to gastric
reflux, intercostal myogenous chest pain) on the case report form directly
after completing history taking, physical examination and possible
ECG-examination and before reading and marking the test result of the PoC
H-FABP-test on the same form. This procedure is seen as the next-best option
after complete blinding, which is impossible to realize in practice since test
results have to be read at the point of care.

In addition, after diagnosis and decision whether or not to refer are
documented on the case report form by the GP, a rapid PoC H-FABP-test will be
performed by the GP in finger prick blood.

Participating GPs will be informed that the PoC H-FABP-test is currently under
study and that the test results can neither be included in their diagnostic
conclusion nor in their decision to refer. Still, the GP is free to revise his
or her decision not to refer to the cardiologist at any moment of the
encounter. Such revised decision should also be recorded. For research purposes
however, it is most important for us to record and analyze the initial decision
of the GP, before PoC H-FABP-testing is performed.

The participating GP will send the case report form (and ECG, if present)
electronically or by telefax to the research team in Maastricht or Leuven. The
research team will contact the GP and, if referral has taken place, the
hospital 30 days after inclusion to collect all relevant patient data (hospital
discharge, GP medical record, patient test results such as biomarkers and ECG).
Final diagnosis will then be set by an independent expert panel.

Burden is very low, there is no particular risk.