OPINION New interventional techniques in the treatment of carotid stenosis Abstract Recent advances in catheter, guide wire and stent design have provided the interventional cardiologist and radiologist with the opportu n ity to treat cerebrovascu lar disease. The role of these new therapies is explored in relation to conventional medical and surgical options. PeterCorr MBChB, FFRAD(D)SA, FRCR, MMed(UCT) Department of Radiology, University of Natal Stroke is the third most common cause of death in South Africa, ac- counting for 9.6 % of all deaths in 1990.1 Stroke is also a major cause of morbidity and contributor to health costs in this country. Most strokes are due to atherosclerotic disease of the proximal internal carotid artery and bifurcation.! Prevention of stroke by treatment of carotid disease is the 4 SAJOURNAL OF RADIOLOGY. June 1997 most important goal of current therapy. Carotid endarterectomy is the treatment of choice if the lesion has a 70% or greater stenosis or by treatment with aspirin if there is a less significant stenosis' Carotid endarterectomy is a safe effective procedure if performed by an experienced surgeon. The Stroke Council of the American Heart Asso- ciation recommends that for carotid endarterectomy to be effective the combined morbidity and mortality must be less than 6%.4 In the NASCET trial the complication rate was 5.8% for perioperative stroke and death and 7.5% in the ECS trial.' Both trials were performed in centres of excellence by highly experienced sur- geons. However a review of published data of 16000 procedures in 50 stud- ies showed a 1.6% mortality but stroke rates from 1 to 35%16 The criti- cal factor is the experience of the sur- geon and the ICU and anaesthetic support in the hospital. Both carotid angioplasty and self expandable stenting have become popular alternative therapies to the treatment of significant carotid steno- sis. Angioplasty of the carotid artery was first performed in 1980 and a number of cardiologists and radiolo- gists have large personal series.Theron recently published his experience with 259 angioplasties over a 12 year period.' He reported a 5% dissection rate and 8% embolic complication rate with the first 38 angioplasties but after changing to a triple lumen cath- eter with a distal balloon to prevent embolism his complication rate de- creased to 2%. Indications for angioplasty would probably be pa- tients unsuitable for endarterectomy. This includes patients with very distal internal carotid artery stenosis above topage5 Nevv interventional techniques in the treatment of carotid stenosis frompage4 the angle of the mandible where sur- gical access is limited. Also included are patients with cardiovascular disease who are an anaesthetic risk. Theron had a restenosis rate of 16% (13 of 81 pa- tients) within the first two years. 8 Contraindications to this procedure are: calcified tortuous arteries that would be difficult to access and to bal- loon, and free floating thrombus on the angiogram-this is an absolute contrain- dication. A major concern is the risk of distal embolisation. It is important that the patient is fully conscious during the pro- cedure and is monitored by a neurolo- gist so that subtle neurological signs can be detected and treated early. If proce- dural thrombosis occurs, urgent throm- bolysis is indicated. If a dissection oc- curs, immediate placement of a stent is required. The CAVATAS trial which is a multieentre randomised study of angioplasty vs endarterectomy is cur- rently being conducted and will pro- vide some of the answers about the role of angioplasty. New developments in stent technol- ogy and design have resulted in the ar- rival of carotid self expandable stents. The most commonly used is the Wallstent (Schneider, Switzerland). The balloon expandable stents have not proved popular because of the risk of distal embolization. Initially indicated for iatrogenic carotid dissection and as an adjunct to angioplasty this procedure has become popular as a primary treat- ment.v" Restenosis following stent in- sertion was seen in 4% of Theron's pa- tients (4 out of 93 cases). The same in- dications and contraindications that ap- ply to angioplasty also apply to primary carotid stenting. Technically this is a de- manding procedure with a steep learn- ing curve. Familiarity with coronary guide wires and low profile coronary balloons is a distinct advantage.There have been no prospective trials of stent vs endartectomy yet. The major concern is the risk of distal embolisation and thrombosis and the long term risk of restenosis. Immediate complications of primary stenting appear to be minimal if meticulous technique is used. Perhaps the most important factor for a good outcome is careful patient selection and working in a team envi- ronment with a stroke neurologist and vascular surgeon. References 1. Bradshaw 0, Bourne DE, Schneider M, Sayed R. Mortality pattern of chronic disease of lifestyle in South Africa. In Chronic Disease of Lifestyle Eds Fourie J and Steyn K. MRC Technical report 1995. 2. Mohr J, Caplan L, Melski 1. The Harvard cooperative stroke registry: a prospective registry. Neurology 1978;28:754-762 3. North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high grade carotid stenosis. NE1M 1991 ;325:445-453. 4. American HeartAssociation.1992. Heart stroke and facts. Bethesed Md 1992;2. 5. Hurst R. Carotid Angioplasty. Radiology 1996;201 :613-616. 6. Rothwell P, Slattery J, Warlow C. A systematic review of the risks of stroke and death due to endarterectomy for symptomatic carotid stenosis. Stroke 1996;27;260-265. 7. Mullan S, Duda E, Petronas N. Some examples of balloon technology in neurosciences. ] Neurosurgery 1980;52:321-329. 8. Theron J, Payelle G, Coskun O. Carotid artery stenosis: treatment with protected balloon angioplasty and stent placement. Radi%gy 1996;201 :627-636. 9. Marks M, Dake M, Steinberg G, Norbash A, Lake B. Stent placement for arterial and venous eer brovascular disease: preliminary experience. Radiology 1994;191:441-446. 10. Eskridge 1. Neurovascular stents. Radiology 1994;191 :313-314 UNIVERSITY OF THE WITWATERSRAND, JOHANNESBURG GA UTENG PROVINCIAL ADMINISTRATION Chief Specialist/Professor (Radiology) Applications are invited from suitably qualified candidates for the above post on the joint staff of the University of the Witwatersrand and the Gauteng Provincial Administration. The post normally carries the academic status of Professor. Applicants should be registrable as specialists with the Interim National Medical and Dental Council. • SALARY: R 191 712 per annum but the total remuneration package is in excess of R 350 000 per annum. • ENQUIRIES: For a detailed information sheet relating to this post, please contact the University's Personnel Office at: (0 ll) 716-2954 / 716-3568. Alternatively, e-mail: 080amd@atlas.wits.ac.za. • To apply, submit a detailed CV with the names and addresses of 3 referees and certi fied copies of degrees/diplomas to: The Personnel Office (Academic), University of the Witwatersrand, Private Bag 3, WITS 2050. \,j oil ~~ CLOSING DATE: 29 AUGUST 1997. QUOTE REF: SA .T/RADIOLOGY 15565. 'THE UNIVERSITY IS AN AFFIRMATIVE ACTION AND EQUAL OPPORTUNITY EMPLOYER' 5 SAJOURNAL OF RADIOLOGY· June 1997 mailto:080amd@atlas.wits.ac.za.