Vascular surgical society of great britain and ireland: carotid angiography is used more selectively in the asymptomatic carotid surgery trial
BACKGROUND: The ongoing Asymptomatic Carotid Surgery Trial (ACST) has randomized more than 1900 patients to determine whether carotid endarterectomy prolongs stroke-free survival compared with best medical treatment alone. Previously the Asymptomatic Carotid Atherosclerosis Study demonstrated that preoperative angiography caused stroke or death in 1 per cent of patients, and many centres have now reduced or abandoned this practice. This study determined the changing practice of carotid angiography in the ACST. METHODS: Collaborating surgeons completed questionnaires annually on their use and method of angiography. Information on patients in the ACST who had angiography at randomization was also obtained. RESULTS: In 1993, 77 per cent of responding collaborators always performed preoperative angiography and 23 per cent used angiography selectively. This trend has reversed: by 1997, 26 per cent always used preoperative angiography, 70 per cent of respondents used preoperative angiography selectively and 4 per cent had abandoned angiography (P < 0.001, chi2 for trend). Information on carotid angiography at randomization has to date been obtained on 1141 patients in the ACST. Some 44 per cent (497 of 1141) had carotid angiography at randomization. Surgical patients had angiography more commonly than those in the medical group (49 versus 42 per cent; P < 0.03, chi2 test). Changes in carotid angiography were analysed by year of randomization. In 1993, 61 per cent of patients randomized had carotid angiography compared with 42 per cent in 1996 and 1997 (P < 0.001, chi2 for trend). The use of carotid angiography was not related to degree of stenosis estimated by Doppler ultrasonography. CONCLUSION: In the ongoing ACST, there is increasingly selective use of carotid angiography. Less than half the patients in this study had carotid angiography and the use of angiography is now decreasing. This has important implications for validation of carotid duplex in this trial and in future studies.
Robless
P
Halliday
A