Proposed duplex velocity criteria for carotid restenosis following carotid endarterectomy with patch closure.

BACKGROUND

Duplex ultrasound velocity criteria have been used to evaluate the severity of carotid stenosis, however, these standard velocities may not be applicable to carotid restenosis after carotid endarterectomy (CEA) with patch angioplasty. The purpose of this study is to determine if patch angioplasty closure alters velocities just distal to CEA and to define the optimal velocities for detecting >or=30%, >or=50%, and >or=70% restenosis.

METHODS

This study includes 200 CEAs randomized into 100 with polytetrafluoroethylene (PTFE) ACUSEAL patch and 100 with Hemashield Finesse patch. All patients underwent immediate postoperative duplex ultrasounds, which were repeated at 1 month and every 6 months thereafter. Patients with a peak systolic velocity (PSV) of the internal carotid artery ([ICA], just distal to the patch) of >or=130 c/s underwent computed tomography angiogram (CTA). PSVs, end diastolic velocities (EDV), and internal carotid artery/common carotid artery (ICA/CCA) ratios were correlated to completion arteriograms/CTAs. Receiver operator characteristic curves analyses were used to determine optimal velocity criteria in detecting >or=30%, >or=50%, and >or=70% restenosis.

RESULTS

One hundred ninety-five pairs of imagings (duplex ultrasound vs CTA/angiogram) were available for analysis. When standard velocity criteria for nonoperated arteries were applied, 37% and 10% of patients were believed to have >or=50% to <70% and >or=70% to 99% restenosis vs 11.3% and 11.3% on CTA/angiography, respectively (P < .001). The mean PSV for >or=30%, >or=50%, and >or=70% restenosis were 172, 249, and 389 c/s, respectively (P < .001). An ICA PSV of >or=155c/s was optimal for >or=30% restenosis with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy (OA) of 98%, 98%, 98%, 98%, and 98%, respectively. A PSV of >or=213 c/s was optimal for >or=50% restenosis with sensitivity, specificity, PPV, NPV, and OA of 99%, 100%, 100%, 98%, and 99%, respectively. An ICA PSV of 274 c/s was optimal for >or=70% restenosis with sensitivity, specificity, PPV, NPV, and OA of 99%, 91%, 99%, 91%, and 98%, respectively. ROC analysis showed that the PSVs were significantly better than EDVs and ICA/CCA ratios in detecting >or=30% and >or=50% restenosis.

CONCLUSIONS

The mean PSVs of a normal ICA distal to CEA patching were higher than normal nonoperated ICAs, therefore, standard duplex velocities criteria should be revised after CEA with patch closure.