|dc.description.abstract||Thrombolysis remains the predominant reperfusion strategy for ST segment
elevation myocardial infarction (STEMI) in the United Kingdom. Although
primary angioplasty may offer superior outcomes, the logistics of delivering this
therapy in the UK have not been investigated. This thesis describes the
development of a pilot primary angioplasty service in North East London.
Outcomes are compared with the thrombolytic strategy, and platelet activation is
explored as a possible biological mechanism determining reperfusion.
The impact of the thrombolytic strategy on revascularisation following STEMI in
North East London was first investigated. Thrombolytic delivery was effective,
but necessitated frequent early revascularisation, leading to prolonged hospital
stay. A primary angioplasty service was developed at the cardiac centre, and
expanded to serve six network hospitals. Within the limitations of a daytime pilot,
the service improved clinical outcomes, and was associated with a substantial
reduction in hospital stay.
Two admission strategies were compared - direct access to the cardiac centre
following pre-hospital diagnosis by ambulance crews, and transfer of patients
presenting to network emergency (A&E) departments after upstream
administration of abciximab and clopidogrel. Direct access significantly reduced
reperfusion times. Upstream anti-platelet therapy improved angiographic
reperfusion prior to primary angioplasty, possibly compensating for inter hospital
A subgroup of STEMI patients underwent platelet activation studies. Lower
baseline platelet monocyte aggregate (PMA) levels predicted improved
angiographic reperfusion following primary angioplasty, supporting the concept
that PMAs may reflect plaque rupture severity, and may promote microvascular
dysfunction. Early anti-platelet therapy reduced PMAs following intervention,
which may explain the benefit of early abciximab observed in clinical trials.
In summary this thesis has demonstrated that primary angioplasty can be
del ivered safely and eff ectively in North East London. The eff icacy of reperf usion
may be determined by mechanisms involving platelet activation. Delivery of a 24
hour seven day service should now be addressed.||en_US