Transient ischaemic attack pre-hospital referral feasibility trial (TIER): recruitment and intervention usage

Early specialist assessment of transient ischaemic attack (TIA) can reduce the risk of stroke and death. This study assessed the feasibility of undertaking a multi-centre randomised trial to evaluate clinical and cost effectiveness of referral of patients attended by emergency ambulance paramedics with low-risk TIA directly to specialist TIA clinics for early review.

We developed a protocol and referral pathway for paramedics to assess and refer patients directly to a TIA clinic, and administer aspirin. We randomly allocated volunteer paramedics to intervention or control groups. Intervention paramedics were trained to deliver the intervention during the patient recruitment period. Control paramedics continued to deliver care as usual. Patients with TIA were identified from hospital records. We aimed to recruit 86 patients and pre-defined progression criteria related to feasibility of intervention delivery and trial methods.

Development and recruitment phases are complete, with outcome follow-up ongoing. Of 134 (66%) paramedics, 89 participated in TIER. Of 1377 patients attended by trial paramedics during the patient recruitment period, 53 (3.8%) were identified as eligible for trial inclusion. Of 36 (8%) patients attended by intervention paramedics, three were referred to the TIA clinic. Of the others, only one appeared to be a missed referral; in one case there was no pre-hospital record of TIA; one was attended by a paramedic who was not TIER trained; one patient record was missing; and all others were recorded with contra-indications: FAST positive (n = 13); ABCD2 score > 3 (n = 5); already taking warfarin (n = 2); crescendo TIA (n = 1); and other clinical factors (n = 8).

Preliminary results indicate challenges in recruitment and low referral rates. The low-risk 999 TIA population suitable for emergency department avoidance may be smaller than previously thought. Further analyses will focus on whether progression criteria for a definitive trial were met, and clinical outcomes from this feasibility trial.