Detection of embolic signals during and after percutaneous transluminal angioplasty of subclavian and vertebral arteries using transcranial Doppler ultrasonography.

OBJECTIVE: Percutaneous transluminal angioplasty (PTA) is accepted as a safe and effective procedure for the treatment of stenotic arterial lesions of various sites. However, distal embolism may cause serious complications in the PTA of cephalic arteries. By monitoring embolic signals using transcranial Doppler (TCD) ultrasonography, we speculated regarding the safety and/or risk of PTA for vertebral and subclavian artery stenosis.
METHODS: Twelve consecutive patients undergoing PTA for subclavian and vertebral artery stenosis of atherosclerotic origin were studied. All patients were refractory to initial medical treatment and were considered for PTA. During the PTA procedure, all patients were heparinized. Before, during, and after PTA, TCD monitoring was performed to detect embolic signals for 30 minutes at each time. After PTA, anticoagulant and antiplatelet therapies were continued in all patients.
RESULTS: Before, during, and after PTA, a steady flow signal could be obtained from each vertebral artery monitored using TCD ultrasonography. No embolic signals were detected in any patient before angioplasty. During angioplasty, one embolic signal was detected immediately after balloon deflation in 1 of 12 patients. Several embolic signals were detected after the procedure in 6 of 12 patients, but thereafter embolic signals became less frequent in number. Three days after angioplasty, embolic signals were not detected in any patient. There were no serious complications caused by the PTA procedure.
CONCLUSION: TCD monitoring may be a useful modality for detection of microemboli during and after PTA in the posterior circulation. We suspected that subclinical microemboli are released from the dilated vessels for 3 days after vertebral and subclavian PTA and that anticoagulant or antiplatelet therapies may prevent embolic complications after the procedure.