Antithrombotic therapy with antiplatelet or anticoagulant drugs is indicated in a wide range of disorders which carry an increased risk of venous, cardiac or arterial thromboembolism. The recommendations in this guideline should therefore be considered when developing several local guidelines:

• Management of venous thromboembolism (section 2)
• Management of atrial fibrillation (section 3)
• Management of other cardiac causes of systemic embolism (section 4)
• Management of ischaemic heart disease (section 5), peripheral arterial disease (section 6), and cerebrovascular disease (section 7)
• Management of oral anticoagulant therapy (section 12).

Development of these local guidelines will require coordinated action by health boards, NHS trusts, general practitioners, relevant hospital medical staff (cardiovascular physicians and surgeons, haematologists, radiologists, anaesthetists), pharmacists, nurses, and the Area Clinical Audit Committee.

Local guidelines should be discussed with and circulated to all relevant staff, and displayed in appropriate areas (primary care clinics, accident and emergency departments, relevant hospital clinics and wards, haematology departments, and pharmacies).

14.1 Patient-specific reminders at time of consultation or admission

These may include proformas in case records; and display of tables and flow diagrams in the above areas. Figures 1-2 and Tables 1-11 may be useful in development of such reminders.

14.2 Continuing education

Continuing education of relevant staff in primary and secondary care (medical, nursing, pharmacy) is desirable in this rapidly-changing area.

14.3 Audit

There is considerable scope for audit of antithrombotic therapy, in both primary care and hospital settings (see section 15). Pharmacists are well-placed to perform such audit activities.

14.4 Inpatient anticoagulation

Published studies indicate that performance is often suboptimal, but can be improved by the availability of summary practice points.^{183, 184} The development and introduction of guidelines for anticoagulation using heparin (see Annex 1) and warfarin (see Annex 2) offer opportunities to audit practice before and after development of local guidelines.

14.5 Outpatient anticoagulation

Again there is evidence of suboptimal performance at hospital anticoagulant clinics.²⁴ Probable reasons include inadequate record keeping and historical reliance on junior doctors who lack experience and/or knowledge of the patient. Supervised training should be part of postgraduate training. Computerisation¹⁶⁰ and involvement of experienced medical staff and/or pharmacists^{179, 180, 181, 182} may improve performance. In primary care, where the patient is likely to be better known to the supervising physician, experience again varies, and studies show a high percentage of patients with INR values outside the target range.¹⁵⁹ Again, the input of a pharmacist may improve performance. Annex 3 outlines an audit protocol for management of oral anticoagulation.¹⁸⁴

14.6 Provision of antithrombotic prophylaxis to patients who may benefit

Several recent audit studies have shown that many patients who may benefit from antiplatelet (aspirin) prophylaxis do not receive it;^{15, 16} and more importantly that patients who may derive a greater benefit from oral anticoagulant (warfarin) prophylaxis, e.g. those with atrial fibrillation, do not receive it.^{25, 26, 185, 186} Audits in both primary care and hospital practice are therefore required to monitor practice.