Sanjay S. Yadav

Carotid Stent-Supported Angioplasty: A Neurovascular Intervention to Prevent Stroke

Obstructive carotid artery disease is responsible for 60% of strokes in the United States and is the third major cause of death. Stent-supported carotid artery angioplasty has the potential to prevent stroke in thousands of patients and offers a number of potential advantages over surgical revascularization (carotid endarterectomy). Results of the prospective observational study at the University of Alabama at Birmingham indicate that carotid stent-supported angioplasty is safe and probably effective in reducing stroke in patients with high-risk cerebrovascular disease. Technical success was achieved in 99% of 146 procedures; 210 stents were placed in 152 vessels, with only 1 instance of stent thrombosis. The rate of major in-hospital complications was unexpectedly low-only 1 death and 2 major strokes. Seven patients suffered minor strokes, but only 2 were left with minor weakness. When compared with a projected complication rate of 6% had these patients undergone carotid endarterectomy, stenting resulted in fewer major events. At 6-month follow-up, 69 of 74 patients were evaluated by angiography or ultrasound, which detected 8 cases of stent deformation and a restenosis rate of < 5%. Because of these instances of stent deformation, use of the Palmaz (biliary) stent was discontinued. Although 1 patient had a transient ischemic attack, no strokes occurred during follow-up. To date, carotid stenting is an investigational procedure. Cardiovascular interventionalists, industry, and the FDA are encouraged to validate this approach through clinical testing. However, improvements in technique, devices, and adjunctive therapies are needed before the method can be tested in randomized trials.

Palmaz stent compression in patients following carotid artery stenting

UNLABELLED Carotid artery stenting is being investigated as a therapeutic strategy for the management of bifurcation stenosis. Palmaz stents were deployed successfully in the carotid arteries of 112 patients using high-pressure balloon inflations. In 11 out of 70 patients who came for 6-mo follow-up angiography, a stent collapse was noted. Carotid ultrasound was able to detect stent collapse in only two patients at follow-up. Only one patient who had collapse of stent along its entire length was symptomatic at follow-up. Repeat balloon angioplasty was performed in 5 patients, 3 of whom had a Wallstents deployed within the Palmaz stent. CONCLUSION Stent collapse was observed in a significant number of Palmaz stents within 6 mo of placement in the carotid arteries. These observations should influence the choice of stents for the treatment of extracranial carotid disease.

Utilization of the Coronary Balloon-Expandable Coil Stent Without Anticoagulation or Intravascular Ultrasound

BACKGROUND The balloon-expandable coil stent has been proved effective in the management of acute and threatened closure after coronary balloon angioplasty and has been shown to reduce restenosis in patients with suboptimal results after coronary balloon angioplasty. Coronary artery stenting has been limited by the occurrence of stent thrombosis and comorbidity related to anticoagulation. This study was undertaken to determine whether anticoagulation may be removed from poststenting protocols, thus reducing comorbidity without increasing stent thrombosis. METHODS AND RESULTS Between September 1994 and May 1995, 369 patients received balloon-expandable coil stents in native coronary arteries at our institution. Of these patients, 216 were selected for a protocol of aspirin and ticlopidine (for 1 month) without anticoagulation. Eligibility for this protocol followed satisfaction of certain procedural and angiographic criteria. These criteria included adequate coverage of intimal dissections, absence of residual filling defects, and normal (TIMI grade 3) flow in the stented vessel after high-pressure balloon inflations. Intravascular ultrasound was not used to guide stent deployment. The stenting procedure was planned in 37% of patients and unplanned in 63% of patients, including 25 (12%) for acute or threatened closure. During the 30-day follow-up period, stent thrombosis occurred in 2 patients (0.9%), there was 1 death (0.5%), and 2 patients (0.9%) underwent coronary bypass surgery. Vascular access-site complications occurred in 4 patients (1.9%), and bleeding that required blood transfusion occurred in 4 patients (1.9%). CONCLUSIONS Patients who receive the coronary balloon-expandable coil stent with optimal angiographic results without intravascular ultrasound guidance can be managed safely with a combination of aspirin and ticlopidine without anticoagulation.

Elective Carotid Artery Stenting in the Presence of Contralateral Occlusion

Significant carotid stenosis in the presence of an occluded contralateral artery has a poor prognosis with medical therapy alone. Carotid cross clamping during surgical endarterectomy results in critical flow reductions in patients with inadequate collateral flow, and represents a significant risk for procedural strokes. Carotid stenting is being evaluated as an alternative to endarterectomy. We describe the immediate and late outcome of a series of 26 patients treated with carotid stenting in the presence of contralateral carotid occlusion. The mean age of the patients in this group was 65 +/- 9 years, 23 (89%) were men and 10 (39%) were symptomatic from the vessel treated. The procedural success of carotid stenting in this group of patients was 96%. The mean diameter stenosis was reduced from 76 +/- 15% to 2.8 +/- 5%. There was 1 (3.8%) minor stroke in a patient who developed air embolism during baseline angiography. At late follow-up there was no neurologic event in any patient at a mean of 16 +/- 9.5 months after the procedure. Thus, carotid stenting of lesions with contralateral occlusion can be performed successfully with a low incidence of procedural neurologic complications and late stroke.

796-2 Application of Lessons Learned from Cardiac Interventional Techniques to Carotid Angioplasty (PTA)

PTA of the carotid and vertebral arteries remains a challenging area of vascular intervention and optimal techniques have yet to be determined. We describe our initial experience with a novel approach to carotid PTA utilizing: 1) “active” perfusion, as is done during coronary angioplasty, which allows prolonged balloon inflations without cerebral ischemia; 2) transcranial doppler (TCD) monitoring, when anatomically feasible, during PTA to assess antegrade flow and detect cerebral emboli; 3) temporary pacing for bradycardia during intra-Carotid balloon inflation; and 4) magnetic resonance angiography (MRA) for screening and follow-up. We have also used the previously described “protected” carotid PTA technique using an additional occluding balloon to prevent cerebral emboli. Six symptomatic patients had 7 PTAs (6 carotids, 1 vertebral). Pt. # Angioplasty Technique Transcrania Doppler StenosisPre→Post Complications Stenosis 3m. F/U 1 Protected 73 emboli 90%→20% none 10% 2 Protected 40 emboli 90%→0% none 0% 3 Active Perf. no window 95%→0% none 0% 4 Active Perf. 10 emboli 99%→0% none 0% 5 Active Perf. no window 99%→0% hemorrh→death 6 Standard no window 100%→30%→ none pending (vertebral) stent→0% Active Perf. 70%→dissec, none pending (carotid) 20%→stent→0% Maintenance of cerebral perfusion during PTA by “active” perfusion and cardiac pacing allows prolonged balloon inflations which minimize residual stenosis; when feasible, TCD monitoring is a valuable adjunct. Ongoing studies with more patients will elucidate the value of this approach for carotid angioplasty.