Systematic review, meta-analysis and economic modelling of ...

Discussiontroponin assays have better early sensitivity than standard troponin assays but are not perfect, so relianceon presentation testing alone will miss cases of MI. Our economic analysis suggests that troponin testingat 10 hours, compared with high-sensitivity troponin testing at presentation, is likely to be cost-effectiveonly if patients can be discharged as soon as 10-hour results are available and if the £30,000/QALYthreshold for willingness to pay is used. If rapid discharge is not achieved, then 10-hour troponin testing isunlikely to represent a worthwhile use of NHS resources.Our analysis also suggests than H-FABP, myoglobin or copeptin could improve detection of MI atpresentation in a cost-effective manner. However, these findings are based on a small number of studiesusing a variety of troponin assays as comparison, so further research is required to determine whetherother biomarkers can consistently improve the early sensitivity of high-sensitivity troponin in a cost-effectivemanner. The evidence is currently insufficient to support their routine use in the NHS.The NICE guidance suggests that patients with negative troponin samples should be reassessed and, ifmyocardial ischaemia is suspected, the guidance for stable chest pain should be followed. 11 In practice, thisis likely to mean that patients presenting to hospital with suspected ACS but negative troponin are selectedfor further investigation, perhaps on the basis of recurrent symptoms that are considered consistent withmyocardial ischaemia. The NICE guidance highlighted that the European Society for Cardiology guidelinesrecommend exercise treadmill testing for these patients despite evidence of limited sensitivity andspecificity, and identified evaluation of CTCA in troponin-negative patients as being a research priority.Our systematic review identified limited evidence to show that CTCA has reasonable diagnostic accuracyfor CAD in patients with suspected ACS but no such evidence for exercise ECG. Both CTCA and exerciseECG had been evaluated in a number of studies that aimed to determine the prognostic value of testingin suspected ACS, but these studies were limited by low event rates, poor reporting and methodologicallimitations. As a result, the evidence that either exercise ECG or CTCA predicts adverse events in suspectedACS is weak and our economic model was based on limited data. The economic analysis showed thatexercise ECG was unlikely to be cost-effective, whereas CTCA could be cost-effective if the risk of adverseevents was sufficiently high (> 2–3% combined death and non-fatal MI rate within the period in whichCTCA might be expected to influence outcome) and the estimates in the model were reliable. The costeffectivenessof CTCA therefore appears to depend on being able to select patients with an increased riskof adverse outcome. Future research needs to explore this issue, but current evidence is insufficient tosupport routine investigation with CTCA for troponin-negative patients.116NIHR Journals Library