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Title: Randomised, prospective study of exercise testing and stress myocardial perfusion SPECT for risk stratification and economic evaluation in a chest pain clinic setting.
Author: Sabharwal, Dr Nikant Kumar
ISNI:       0000 0001 3544 2085
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2006
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Background. The identification and risk stratification of patients with chest pain is an important determination for any system treating coronary artery disease (CAD). Exercise electrocardiography (ETT) is currently the mainstay of physiological testing in patients with suspected angina. Newer non-invasive methods of detecting ischaemia are available and provide improved diagnostic and prognostic ability. In particular, objective evidence of myocardial ischaemia by myocardial perfusion imaging (MPI) improves diagnosis and risk stratification in patients with suspected coronary artery disease. There have been no randomised prospective trials between ETT and MPI. Hypothesis. A first line MPI strategy would be more effective and cost saving compared to ETT for stable chest pain patients attending an outpatient clinic. Methods. 503 patients with stable chest pain were randomised to either same day ETT or MPI with gated 99mTechnetium sestamibi single photon emission computed tomography (SPECT). Patients were stratified according to their pre-test likelihood of CAD. Standard hospital treatment guidelines were applied to each arm based on the results of each of the tests. The cost to reach a diagnosis was calculated from institutional and published United Kingdom National Health Service (NHS) costs. Supplied by The British Library - 'The world's knowledge' - Results. MPI reduced the proportion of patients with an intermediate post-test likelihood of CAD (ETT 30.4% [72/237] v MPI 3.4% [9/266], p<0.0001), and reduced the proportion of patients requiring a further investigation to diagnose CAD compared to ETT (ETT 72.6% [172/237] v MPI16.9% [45/266], p<0.0001). MPI also reduced the requirement for coronary angiography (ETT 49.4% [117/237] v MPI 16.9% [45/266], p<0.0001) and the proportion of normal coronary angiograms (ETT 30.8% [36/117] v MPI 11.1% [5/45], p=0.02). Cost analysis showed no statistical difference between the mean costs for each diagnostic arm (ETT £490.44 [95%CI 453.80 - 527.08] v MPI £512.41 [95%CI 481.41 - 543.41]). Cost analysis of patients, with an intermediate and high pre-test likelihood of CAD, showed that MPI was not statistically different from ETT, primarily due to the reduction in the number of cardiac investigations and interventions subsequently required in the MPI arm. Conclusions. ETT is preferred for diagnosis and in terms of cost in low pretest likelihood patients. However MPI has a diagnostic advantage as the initial test in those referred with stable chest pain with an intermediate and high pretest likelihood. Although MPI showed no cost differences overall, there were fewer investigational procedures in intermediate and high pre-test likelihood patients. In an era of early referral for suspected chest pain the ETT may not provide adequate diagnostic and prognostic information. This data suggests that MPI is the preferred test in stable chest pain patients with an intermediate or high pre-test likelihood of CAD. This is likely to have resource implications for the NHS.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available