Primary care decision rule for chest pain using the Marburg heart score rule and troponin point of care test

Every day, in the Netherlands, 600-1200 patients visit their general
practitioner (GP) with chest pain. Chest pain may reflect coronary artery
disease (CAD) or acute coronary syndrome (ACS) for which urgent referral to a
cardiologist is necessary.] However, chest pain in primary care is caused by
CAD in only 10-15% of patients, and by ACS in only 4-7%. Current usual practice
is based on the guideline of the Dutch College of General Practitioners. This
guideline states that individual signs and symptoms should direct the GP to
decide on a referral to secondary care. It is known, however, that this has
very low diagnostic value (sensitivity reported 69% up to 92-94%; 6-17% miss
rate).[1, 5-9] As a consequence, GPs are cautious not to miss ACS and
therefore refer many patients (40-70%) to the cardiologist, at the cost of low
specificity (high number of unnecessary referrals). These unnecessary referrals
result in uncertainty for doctors and patients, and high health care costs for
society. A decision aid to safely exclude CAD in patients presenting with chest
pain in primary care could fill this gap in current practice. The Marburg Heart
Score (MHS) is a clinical decision rule previously validated and currently used
in primary care in Germany with a known sensitivity of 98,8% for ruling out
CAD. Recently the possibility for point of care testing (POCT) of troponin
became available with test results within 10 minutes, creating opportunities
for use in primary care.

To determine the effectiveness of a decision rule compared to the usual care of
GP*s for patients presenting with non-traumatic chest pain in primary care.

A clustered randomized trial. 90 primary care practices include 1500 patients
with chest pain.
Practices will be randomized 2:1, the intervention group will be twice the size
of the control group.
Additionally, a second control group will be selected from routine care data
from 2 datawarehouses.

Clinical decision rule consisting of the Marburg Heart Score in combination
with high sensitivity troponin point of care test

The burden and risk for the patient is minimal. At the time of inclusion in the
interventiongroup a fingerstick bloodtest will be performed. After inclusion
there will be 3 more contact moments, where patients will be asked to fill in a
questionnaire. The total time needed is estimated at approximately 120 minuten.

The risk of harm to the patient following our intervention is low. However,
there is always a small chance of a false negative result of the clinical
decision rule. A patient may be left at home and suffer ACS there. Although the
chance is small, consequences for the patient can be severe, due to delay in
the diagnostic and therapeutic work-up.

It is good to realize however that in current daily practice the estimated
miss-rate for ACS is estimated to be between 6-15% and developing a diagnostic
test with 100% sensitivity is impossible.

As extra safety we allow GP's to overrule the decision rule if they deem
necessary for the safety of the patients. Furthermore, GP's are instructed that
the diagnostic process does not end after the decision rule and another
explanation/diagnosis for the chest pain needs to be sought.