Non-invasieve beeldvorming bij symptomatische A.-carotisstenose: goede diagnostische waarde en kosteneffectiviteit bij de combinatie van duplexonderzoek en magnetischeresonantieangiografie (MRA)

Objective. To investigate whether digital subtraction angiography (DSA) in the diagnosis of carotid artery stenosis can be replaced by non-invasive testing. Design. Prospective diagnostic study and cost-effectiveness analysis. Method. In 350 consecutive symptomatic patients who were eligible for a DSA, duplex ultrasound (DUS), magnetic resonance angiography (MRA), and DSA were performed. Assessment of all tests was blinded. The test results of DUS and MRA were compared with the reference standard, DSA. A cost-effectiveness analysis was performed on the basis of these data. Results. DUS resulted in a sensitivity of 87.5% (95% CI: 82.1-92.9) and a specificity of 75.7% (95% CI: 69.3-82.2) in identifying severe A. carotis interna stenosis (70-99%). Stenosis measurements on MRA yielded a sensitivity of 92.2% (95%CI: 86.2-96.2) and a specificity of 75.7% (95% CI: 68.2-82.5). Combining MRA and DUS results, agreement between these two modalities (84% of patients) gave a sensitivity of 96.3% (95% CI: 90.8-99.0) and a specificity of 80.2% (95% CI: 73.I-87.3). The use of DUS, MRA, and the combination of DUS and MRA resulted in comparable outcomes in terms of QALYs and total lifetime costs, whereas DSA resulted in QALY loss and higher costs. Conclusion. In most patients with suspected severe A. carotis stenosis and who are being considered for endarterectomy, DSA can be replaced by the combination of DUS and MRA. Should a discrepancy arise between the findings of these procedures however, DSA should still be considered.