Percutaneous transluminal angioplasty (PTA) for stenosis at the subclavian artery and at the origin of the vertebral artery: Therapeutic indication and some adjunctive safe methods during PTA

Percutaneous transluminal angioplasty (PTA) for brachiocephalic occlusive lesions has progressed. In this paper our experiences and results of PTA in dealing with those lesions are described with emphasis on adjunctive procedures during PTA. Recently, twenty-four patients with stenosis of the subclavian artery (SA) and/or stenosis at the origin of the vertebral artery (VA) were included in this study. Among the 24, there were 16 cases with SA stenosis, 6 cases with stenosis at the origin of VA and 3 cases with both SA and stenosis at the origin of VA. The stenosis was due to atherosclerosis in 21 cases and aortitis in 3 cases. Most of the patients presented ischemic symptoms of vertebrobasilar circulation and affected upper extremities. In PTA of brachiocephalic lesions, one of the most formidable complications is an embolism distal to the central nervous system. To prevent this complication, a vascular endoscope was used for visualization of the luminal surface of the stenotic lesions in 7 cases, and a protective balloon was used in 4 recent cases. The protective balloon was used for transient occlusion of the artery to alter the flow direction so that the possible emboli might be forced to flow away to a less critical distal artery. In the distal protective balloon technique, the protective balloon was set so as to occlude the stenotic artery distally. Debris caused by PTA was aspirated and/or washed out to an extracranial artery with heparinized saline. In the proximal protective balloon technique, the protective balloon was set so as to occlude the stenotic artery proximally. Debris was washed out with blood flow caused by the induced steal phenomenon to an extracranial artery. In one case, in which there was stenosis in the left SA and at the left origin of the VA, kissing balloon technique was performed. Immediate post-PTA results were excellent and good in 21 cases, and poor in 3 cases including one in which the catheter could not be inserted to allow PTA to be performed. Follow-up angiography showed re-stenosis in 2 cases, and in one of them re-PTA was performed. No major complication was observed during PTA. No distal embolism was observed in any case. Vascular endoscopic observations showed the stenosed luminal surfaces before PTA were smooth and regular. No ulcer formation was observed. Therapeutic indication of extracranial occlusive lesions based on our experience was found in patients who had vertebrobasilar ischemic symptoms with more than 50% stenosis of VA bilaterally, or more than 50% stenosis of VA ipsilaterally, and aplasia or hypoplasia of VA and hypoplasia of VA at distal PICA contralaterally to the stenosis at the origin of VA. In SA stenosis, therapeutic indicaton was found in patients with ischemic symptoms of vertebrobasilar and/or upper extremity. Recent surgical technique for extracranial occlusive lesions is transposition of VA which has a low mortality and morbidity rate. Considering the fact of invasive intervention associated with surgery and anesthesia, PTA is an alternative treatment. Recent reports and our experience indicate a high rate of success and rare occurrence of complications. Also safer PTA can be performed using some adjunctive procedures such as those mentioned in this report during PTA.