Implementation of a clinical prediction tool for pulmonary embolism diagnosis in a tertiary teaching hospital reduces the number of computed tomography pulmonary angiograms performed.

AIM: To evaluate the effect of implementing the Wells score clinical prediction tool (CPT) on rationalising the use of computed tomography pulmonary angiography (CTPA) for diagnosing pulmonary embolism (PE). METHODS: Within a tertiary teaching hospital, a retrospective study was conducted applying Wells score to all CTPA ordered in the first quarter of 2007. Subsequently, an algorithm including Wells score and d-dimer assay was developed to assist clinicians in rationalising their ordering of CTPA. A prospective study was performed from February to August 2009 to assess the impact of this algorithm. CTPA results, d-dimer levels, referral sources and dates were recorded. The number of CTPA performed over a 7-month period following implementation of the algorithm was compared with the same period during the previous year. PE prevalence within each risk category was compared with the published literature. RESULTS: Three hundred and thirty-three patients were investigated with CTPA in the prospective study period. Two hundred and sixty-eight patients (80.4% of cases) had complete data. The prevalence of PE in the present study was 13.8% with 57 (21.2%) patients stratified to low risk, 169 (63.0%) to intermediate risk and 42 (15.6%) to high risk. Subgroup prevalence was 8.8%, 11.8% and 23.8% respectively. Compared with the same period in 2008, 121 (26.6%) less CTPA were performed. CONCLUSION: Institutional implementation of a clinical prediction tool into the decision-making process is feasible and significantly reduces the number of CTPA being performed, with substantial cost savings and patient benefits.

Multislice computed tomography coronary angiography: risk stratification of patients in the perioperative period.

Multislice computed tomography coronary angiography is emerging as a reliable non-invasive method for the assessment of coronary artery disease, coronary anatomy and cardiac function. Improvements in computed tomography technology hold the promise of replacing the standard invasive procedure of conventional coronary angiography in selected patient groups. The ability of a six-second scan to identify flow-limiting coronary artery stenoses as well as characterising coronary atheromatous plaque components provides valuable information that can assist in refining perioperative cardiovascular risk. Multislice computed tomography's high negative predictive value and high specificity for stenoses allows it to effectively rule out coronary artery disease in patients with cardiac risk factors who have non-diagnostic or equivocal non-invasive cardiac stress tests. Other uses include evaluating patients who are symptomatic following percutaneous coronary intervention, evaluating coronary artery bypass grafts and coronary stent patency, detecting coronary stenosis prior to valve surgery and assessing coronary anatomy in patients with technically difficult arterial access. Avoiding the small but definite risks of conventional coronary angiography makes cardiac computed tomography an appealing alternative. An overview of multislice computed tomography is presented with particular attention placed on its role in the risk stratification of selected patients in the perioperative period. A risk stratification algorithm is suggested.