Background Primary PCI (PPCI) is the preferred treatment for patients presenting with ST-elevation myocardial infarction (STEMI). Strategies to minimise PCI-related delayinclude bringing patients directly to the cath lab following ECG transmission. The aim of this study was to assess the frequency, appropriateness and clinical outcomes of patients turned down for PPCI by this process.

Methods The Belfast PPCI pathway is activated by CCU nurses according to a regionally agreed protocol. Electrocardiograms (ECG) are faxed to a central hub in conjunction with a focussed telephone conversation. If a decision is made not to activate the PPCI team, the referral is deemed a turn-down and the clinical data are retained. All primary PCI turn-downs from the end of September 2013 until the end of March 2014 were reviewed retrospectively with analysis of electronic care records, laboratory results, referral ECG and angiographic images and procedural reports where relevant. A turn-down was deemed inappropriate if retrospective review demonstrated diagnostic ECG criteria with either a culprit lesion at subsequent angiography or significant troponin rise or new regional wall motion abnormalities at echocardiography.

Results Between 30^th September 2013 and 31^stMarch 2014, 945 cases were referred to the PPCI service (about 5 per day). The majority (556/945: 59%) were turned down. Of the remainder, 315 (33%) patients underwent primary PCI and 74 (8%) activated the PPCI team but did not proceed to PCI.

The Northern Ireland Ambulance Service (NIAS) was the commonest source of referrals (667 cases) the majority of which were turned down (Table 1).

Three percent of turn-downs (17 patients) were deemed inappropriate. 3 were due to logistical problems whilst 14 were due to inaccurate reading of the ECG or interpretation of clinical history. 28 cases were re-referred from emergency departments, having been initially turned down; 7 of these were subsequently categorised as inappropriate turn-downs. Within the group deemed inappropriate turndowns 53% (9 cases) had been reviewed by the medical team compared with 12% overall. Six-month mortality among the patients appropriately turned down was 13.5% (73 patients) compared with 11.8% (2 patients) among the inappropriate turndowns.

Conclusion In this PPCI service, the majority of patients referred are turned down appropriately, largely due to a high rate of turn-down from the ambulance service. Clinical outcomes were similar among patients turned down appropriately and inappropriately.