Percutaneous transluminal angioplasty versus surgery for subclavian artery occlusive disease

Percutaneous transluminal angioplasty of the subclavian arteries

PURPOSE

To review the feasibility, risks, and long-term results of subclavian artery angioplasty with and without Palmaz stent placement.

METHODS

Over a 9-year period, 113 patients (67 males; mean age 63 +/- 13 years) underwent percutaneous balloon angioplasty of subclavian occlusive lesions for a variety of indications: vertebrobasilar insufficiency (n = 70), upper limb ischemia (n = 50), coronary steal syndrome (n = 6), or anticipated coronary artery bypass grafting using the internal mammary artery in 12 asymptomatic patients. There were 94 (83%) stenoses and 19 (17%) occlusions with a mean percent stenosis of 80.1% +/- 7.4% (range 70 to 100). Mean lesion length was 24 +/- 8 mm (range 10 to 50). Beginning in 1989, stents were implanted for suboptimal dilation; in 1995, stenting became routine.

RESULTS

Overall, 103 (91%) of 113 lesions were successfully treated; 10 (53%) occlusions could not be recanalized. Fifty-one stents were implanted in 46 patients. There were 3 (2.6%) procedural complications: a transient ischemic attack, one major (fatal) stroke, and an arterial thrombosis 24 hours after the procedure (treated medically) (0.9% major stroke and death rate). During a mean 4.3-year follow-up (range to 10), 16 (15.5%) restenoses were treated with angioplasty (n = 4), stenting (n = 7), or surgery (n = 5). Primary and secondary patencies for all treated lesions (n = 113) at 8 years were 75% and 81%, respectively; in patients without initial stent placement, the rates were 69% and 76%, while in those with stents, the rates rose slightly to 87% and 94% at 2.5 years (NS). Patency rates for all 103 recanalized lesions were 83% and 90% at 8 years (81% and 90% without stent and 87% and 94% with stent at 2.5 years, respectively [NS]).

CONCLUSIONS

Balloon angioplasty with or without stenting is safe and effective for treating subclavian artery occlusive diseases with good long-term patency. Recanalization of occlusions is more difficult to achieve. Stents (implanted only for suboptimal dilation) do not seem to improve long-term patency.

REVASCULARIZATION OF THE ISCHEMIC UPPER LIMB

Eighteen cases of upper limb ischemia were operated during a 24 month period. Eleven patients presented with features of chronic ischemia, while 7 had acute ischemia with a threatened limb. There were 15 males and 3 females. The average age was 38 years. Associated medical problems were present in 8 patients. Limb perfusion was restored in all patients after direct arterial (bypass) surgery, intra-arterial thrombolysis or percutaneous transluminal angioplasty (PTA). There was no mortality. The limb salvage rate was 100 per cent. Follow-up of upto 24 months reveals a patent bypass in all patients with no recurrence of symptoms. Upper limb ischemia is not uncommon, and can be treated by thrombolysis, angioplasty or bypass surgery. Direct arterial surgery for upper limb revascularization, though technically demanding, is safe and results in relief of symptoms in the vast majority of patients.

A combined approach to the treatment of proximal arterial occlusions of the upper limb with endovascular stents

BACKGROUND

The traditional transfemoral approach to endovascular stenting is not ideal for proximal arterial lesions of the upper limb. The distance of the lesion from the femoral puncture site, flexibility and unsupported length of guide-wires/delivery systems and often acutely angled origins of the great vessels combine to make crossing the lesions and accurate deployment of the device difficult or impossible. Deployment of the stent via a brachial arteriotomy should obviate these problems.

AIM

The authors report a series of patients with proximal arterial occlusions of the upper limb treated by endoluminal stenting using a combined surgical/radiological approach.

PATIENTS AND METHODS

Using the combined approach we have attempted to treat 18 proximal upper limb occlusions (eight brachiocephalic origin, six subclavian origin, two subclavian artery and two axillary artery). Where possible, occlusions were treated by primary stent deployment. All patients received perioperative i.v. heparin followed by long-term aspirin.

RESULTS

Revascularisation was successful in 15 of 18 proximal occlusions with complete resolution of symptoms. All stented vessels remain patent up to 36 months after the procedure and there have been no complications arising from the brachial arteriotomy sites.

CONCLUSIONS

Primary stenting is the treatment of choice for proximal occlusions of the upper limb vessels. A combined surgical/radiological approach via a brachial arteriotomy can be used in these cases and is now the method of choice for the treatment of such lesions in this unit.

Techniques for endovascular recanalization of supra-aortic trunks

The supra-aortic are no stranger to endovascular interventions. Since the 1980s, interventionists have been evaluating and refining the use of transluminal techniques for recanalizing stenotic and occlusive lesions in these large-bore, high-flow vessels. The authors present their methodologies for evaluating, selecting, and treating supra-aortic lesions with balloon angioplasty and stenting. Helpful suggestions are offered for optimizing the outcome of these endovascular approaches to atherosclerotic occlusive disease in the supra-aortic trunks.

Supra-aortic arterial stenoses: management with Palmaz balloon-expandable intraluminal stents

PURPOSE

The authors report on the use of Palmaz balloon-expandable intraluminal metallic stents to supplement conventional balloon angioplasty and to primarily treat a variety of supra-aortic arterial atherosclerotic lesions manifested by claudication or embolic phenomena.

PATIENTS AND METHODS

Results from a series of seven patients are reported. Five patients received stents following percutaneous balloon angioplasty (PTA): four patients received five stents for suboptimal initial result of PTA and one patient received one stent for early restenosis following successful PTA. Two patients received three stents primarily: one patient had one stent placed for a highly eccentric innominate lesion and the other patient had two stents placed for an ulcerated nonocclusive subclavian lesion causing blue digits.

RESULTS

Treatment produced immediate angiographic or hemodynamic improvement in all seven patients. Clinical follow-up was obtained on all patients (mean, 10 months; range, 3-18 months). One patient had an episode of vertigo after PTA of a right subclavian lesion that resolved after thrombolytic therapy and stent placement.

CONCLUSION

The placement of metallic stents in supra-aortic arteries represented an effective adjunct to PTA of atherosclerotic stenoses in these vessels. Primary stent placement may be an effective treatment for selected lesions.

Subclavian carotid transposition: an analysis of a clinical series and a review of the literature

OBJECTIVE

To analyse the clinical results and long-term patency rates of 108 patients with subclavian carotid transposition (SCT) and compare the outcomes to other clinical series using the same technique, as well as to those reported for other surgical procedures and PTA in the treatment of proximal subclavian artery disease.

METHODS

The hospital records of 108 patients with carotid subclavian transposition were retrospectively reviewed for preoperative symptoms, Doppler examination, arteriography, blood pressure differentials and postoperative complications. Long-term patency and symptoms were determined during a follow-up examination including a history, physical examination, blood pressure differentials, Doppler examinations and arteriography in selected cases.

RESULTS

The indication for SCT were subclavian steal (78%), upper extremity ischaemia (59%), rest pain or acral necrosis (5%), vertigo (6%). There was no mortality, blood pressure differentials were equalised in all patients without any early reocclusions. The complication rate was 15% with a permanent morbidity of 3%. Eighty-four patients (77%) could be re-examined during follow-up. For them the overall patency after a mean observation period of 70 months (1-144 months) was 100%.

CONCLUSIONS

Subclavian carotid transposition is an excellent method for the treatment of proximal subclavian occlusive disease because of its exceptional long-term patency and low morbidity.

Percutaneous transluminal stent placement to treat subclavian steal syndrome

PURPOSE

To describe nonsurgical stent placement to treat subclavian steal syndrome after failure of traditional balloon angioplasty.

PATIENTS AND METHODS

Seven patients with subclavian steal syndrome underwent diagnostic angiography, which showed four stenoses and three occlusions of the proximal left subclavian artery. Most patients presented with vertigo, left arm claudication, or syncope. Initial balloon angioplasty failed; there was elastic recoil with more than 30% residual stenosis or subintimal dissection. The three occlusions were treated with urokinase pulse-spray thrombolysis. All seven patients then underwent stent placement.

RESULTS

Initial technical success was achieved in all seven cases (100%), with an average right versus left arm blood pressure gradient of 0 mm Hg (-11 to 12 mm Hg) at mean follow-up of 12 months (4-24 months) (positive gradient = systolic pressure of right arm > that of left arm; negative gradient = systolic pressure of left arm > that of right arm). Symptoms of arm claudication and syncope resolved, and vertigo improved or resolved after the procedure. There were no deaths, strokes, or emboli in the perioperative or follow-up period.

CONCLUSION

Percutaneous transluminal stent placement may be an effective treatment of subclavian steal syndrome in patients with lesions that are refractory to traditional angioplasty.

Extrathoracic reconstruction of arterial occlusive disease involving the supraaortic trunks

PURPOSE

The purpose of this study was to review the various extrathoracic reconstruction options in patients with occlusive disease of the supraaortic trunks and to define the efficacy of these procedures in maintaining graft patency and relieving symptoms.

METHODS

Forty-four consecutive patients underwent 47 extrathoracic bypass procedures of the supraaortic trunks for correction of symptomatic subclavian (SCA), common carotid (CCA) or innominate (INA) artery occlusive disease between July 1975 and May 1994. SCA stenosis (n = 27) was associated with upper extremity claudication (55%), vertebrobasilar insufficiency (15%), or both (30%). CCA stenosis (n = 14) was accompanied by hemispheric symptoms in 86% and global ischemia in 14%, whereas INA stenosis (n = 3) was associated with transient ischemic attacks (67%) and right arm ischemia (33%).

RESULTS

SCA revascularization included carotid-subclavian or carotid-axillary bypass (n = 19), axilloaxillary bypass (n = 8), and subclavian-carotid transposition (n = 3). CCA reconstructions included subclavian-carotid (SC) bypass (n = 13) and carotid-carotid bypass (n = 1). INA procedures included three axilloaxillary bypasses. Six patients had an associated carotid endarterectomy, and three underwent concomitant vertebral artery transpositions. Intraluminal shunts were not routinely used. Vein was used as a conduit in five procedures, and a prosthetic graft (23 Dacron, 16 polytetrafluoroethlyene) was used in the remainder. The average postoperative intensive care unit and hospital and hospital stay were 1 and 5 days, respectively. Follow-up was available in 43 of 44 patients (mean = 26.2 months). The perioperative mortality rate was 2.2% (one axilloaxillary). There were five graft occlusions in procedures involving the axillary artery (3 of 11 axilloaxillary, 2 of 7 carotid-axillary) as compared with one of 29 thromboses when the operation was confined to the supraclavicular fossa (p < 0.05) Relief of symptoms was achieved in all patients with patent grafts. There were no perioperative strokes in the series. Other complications included one brachial plexus neuropraxia (axilloaxillary) and four patients with phrenic nerve neuropraxia.

CONCLUSION

Extrathoracic revascularization of the supraaortic trunks is well tolerated and durable when operations are confined to the supraclavicular fossa and do not involve the axillary artery.

Primary stent deployment in occlusive subclavian artery disease

Primary (without antecedent balloon dilation) Palmaz stent implantation was successfully performed in 27 consecutive patients entering with 31 obstructed subclavian arteries. Stents (n = 50) were successfully deployed, using the brachial (n = 7), femoral (n = 16), or combined (n = 8) approach, to revascularize 31 subclavian vessels [8 occluded (26%); 23 stenotic (74%)], using a 6 or 7.5 French delivery system. The indications for intervention were arm claudication in 8 patients (30%), subclavian steal syndrome in 11 patients (41%), angina pectoris secondary to impaired blood flow to the left internal mammary artery coronary bypass in 6 patients (22%), and recanalization of a left subclavian occlusion to permit central arterial access and performance of a second interventional procedure 2 patients (7%). The percent diameter stenosis improved from 85 +/- 12% to 6 +/- 7% (P < 0.001); and, the peak and mean translesion gradients decreased, respectively, from 56 +/- 35 mm Hg to 3 +/- 4 mm Hg (P < 0.01), and 29 +/- 18 mm Hg to 2 +/- 2 mm Hg (P < 0.01). Procedural complications encountered were one stent dislodgement with migration into and uneventful deployment within the right external iliac artery, and two brachial artery repairs. No acute vessel closures, deaths, myocardial infarctions, cerebrovascular accidents, transient ischemic attacks, or need for transfusions occurred. Therefore, primary subclavian artery stent deployment can be performed using low-profile sheath systems with excellent success (100%), resulting in immediate restoration of pulsatile flow, and few complications. The incidence of lesion recurrence remains for follow-up studies.

Coronary-subclavian steal syndrome: report of five cases

The internal mammary artery (IMA) is the conduit of choice for cardiac revascularization. The phenomenon of retrograde flow in this graft secondary to proximal subclavian artery stenosis is an infrequent but increasingly recognized clinical entity and has been termed the "coronary-subclavian steal syndrome." We report on five patients with this syndrome. All were men. The average age was 65 years (range 56 to 68 years). The mean interval from coronary bypass to presentation was 7.8 years (range 1 month to 18 years). Three patients presented with unstable angina and one with congestive heart failure. One patient was asymptomatic from a cardiac standpoint. The mean arm systolic blood pressure differential was 45 mm Hg (range 30 to 60 mm Hg). Each patient underwent cardiac catheterization, and retrograde IMA flow was demonstrated in 100%. Arteriography confirmed the presence of a proximal high-grade (> 75%) subclavian stenosis in all patients. Stress thallium scanning was performed in two patients and demonstrated anterolateral ischemia in both. Operative intervention in four patients consisted of a left carotid-subclavian bypass using an 8 mm synthetic graft. There was no perioperative morbidity or mortality. Postoperative thallium scanning revealed resolution of the ischemic process. The average length of follow-up was 20 months (range 12 to 25 months) with all patients remaining asymptomatic. The one patient who refused surgery died at 12 months. When IMA grafting is contemplated, proximal subclavian stenosis should be suspected if there is > 20 mm Hg systolic pressure differential between the arms.(ABSTRACT TRUNCATED AT 250 WORDS)

Endoluminal stenting of a subclavian artery stenosis to treat ischemia in the distribution of a patent left internal mammary graft

Subclavian artery stenosis is a rare cause of recurrent myocardial ischemia in patients who have undergone left internal mammary-coronary artery bypass grafting. A patient with this syndrome was successfully treated by placement of Palmaz biliary stents in the left subclavian artery. Angiographic and hemodynamic evidence of restricted subclavian flow resolved following stenting, as did the patient's unstable angina syndrome. Endoluminal stenting of the proximal subclavian artery for the treatment of coronary-subclavian steal can be performed safely and provides an alternative to other forms of surgical or percutaneous (PTCA, directional atherectomy) revascularization for treatment of this disorder.

Carotid-subclavian bypass: a twenty-two-year experience

PURPOSE

A retrospective review of 124 patients who underwent carotid-subclavian bypass from 1968 to 1990 was done to assess primary patency and symptom resolution.

METHODS

Preoperative data included age, atherosclerosis risk factors, and indications for surgery. Perioperative data included mortality and morbidity rates and graft conduit. Postoperative follow-up assessed graft patency, resolution of symptoms, and late survival.

RESULTS

Age ranged from 42 to 78 years (mean 57.9). Indications for surgery were vertebrobasilar insufficiency in 24 (19%), extremity ischemia (EI) in 33 (27%), transient ischemic attacks (TIAs) in 13 (11%), both vertebrobasilar insufficiency and EI in 31 (25%), and both TIAs and EI in 23 (18%) patients. Graft conduits were polytetrafluoroethylene in 44 (35%) and Dacron in 80 (65%) cases. Concomitant ipsilateral carotid endarterectomy was done in 32 (26%) patients. During operation, death occurred in one patient (0.8%), and complications occurred in 10 (8%) patients. Thirty-day primary patency and symptom-free survival rates were 100%. Long-term follow-up ranging from 5 to 164 months was available for the 60 cases done between 1975 and 1990. Three grafts occluded at 30, 36, and 51 months after surgery for a primary patency rate of 95% at 5 and 10 years. Twenty-two patients died, yielding survival rates of 83% at 5 years and 59% at 10 years. Symptom recurrence occurred in six (10%) patients from 9 to 66 months after surgery. The symptom-free survival rate was 98% at 1 year, 90% at 5 years, and 87% at 10 years. Symptoms recurred in three patients with occluded grafts and three with patent grafts. The preoperative symptoms of drop attacks and TIAs did not recur. EI recurred in 5% and was noted only in the presence of graft occlusion. Dizziness recurred in 17% of patients admitted with this symptom and was observed despite graft patency.

CONCLUSION

Carotid-subclavian bypass was a safe and durable procedure for relief of symptomatic occlusive disease of the subclavian artery. Long-term symptomatic relief appeared particularly likely in patients with drop attacks or upper extremity ischemia.

Transluminal angioplasty of the subclavian artery in patients with internal mammary grafts

From January 1987 to January 1992, 11 patients underwent percutaneous transluminal angioplasty (PTA) for the treatment of subclavian artery stenosis before or after coronary artery bypass grafting (CABG) using the internal mammary artery (IMA). There were 8 men and 3 women, with a mean age of 57 +/- 7 years. Four patients had PTA 1 to 4 months before undergoing CABG with IMA grafts, because of either asymptomatic supraclavicular murmurs or neurologic symptoms. Seven patients underwent PTA 2 to 37 months after CABG with IMA grafts, because of recurrent angina. Subclavian artery stenosis was on the left side in 9 patients, the right side in 1 patient, and bilateral in 1 patient. Ten PTA procedures were successful in 9 patients. All patients with post-CABG angina had reversal of the ischemia. There were three complications: one femoral artery thrombosis, one brachial plexus hematoma after an axillary approach, and one acute pulmonary edema after the procedure. Follow-up after PTA ranged from 1 to 60 months (mean, 38 +/- 17 months). Nine patients had no angina at follow-up and 2 had stable angina (class II) upon exertion. Upper-limb Doppler studies showed no evidence of restenosis in any of these patients at a mean follow-up of 38 months. Subclavian artery PTA is a useful alternative to IMA bypass grafting in patients with subclavian artery stenosis discovered preoperatively, and it is the treatment of choice for those presenting with post-CABG angina due to subclavian artery stenosis proximal to an IMA graft.

Atherectomy of the subclavian artery for patients with symptomatic coronary-subclavian steal syndrome

OBJECTIVES

This study addresses the efficacy of directional atherectomy in the subclavian artery for the relief of angina in patients with the coronary-subclavian steal syndrome. In addition, we review the histologic findings from the atherectomy specimens.

BACKGROUND

The coronary-subclavian steal syndrome may occur after internal mammary-coronary artery bypass grafting. It is due to a stenosis in the subclavian artery proximal to the origin of the internal mammary artery and causes frank ischemia to the area supplied by the graft. Currently, surgery is the corrective procedure of choice.

METHODS

In three patients with severe subclavian artery stenoses and unstable angina, directional atherectomy was performed using a peripheral atherectomy catheter through a percutaneous femoral approach. The patients ranged from 43 to 71 years of age and had undergone internal mammary-coronary artery bypass grafting 3 to 10 years previously. Each patient had severe peripheral vascular and cerebrovascular disease.

RESULTS

All three patients had immediate symptomatic relief after the atherectomy, and postprocedure exercise testing demonstrated improved cardiac function. Two patients remain asymptomatic at 7 and 8 months, respectively; the third patient developed unstable angina 9 months later because of severe restenosis that was again successfully treated with atherectomy. Histologic examination of the specimens revealed atherosclerotic plaque, occasionally with adventitia. The specimen from the repeat atherectomy showed severe intimal hyperplasia.

CONCLUSIONS

Directional atherectomy appears to be a safe and effective treatment for coronary-subclavian steal syndrome. This procedure may be the treatment of choice for patients in whom a vascular bypass operation is not feasible.

Subclavian angioplasty: immediate and late results in 50 patients

In order to assess the therapeutic outcome of percutaneous transluminal angioplasty for subclavian stenosis, 50 patients were followed up clinically as well as with a velocimetric Doppler after attempted angioplasty. A minimal clinical follow-up of 9 months was expected. Subclavian stenoses were due to atheroma in 49 patients and to Takayasu's disease in 1 case. Indication of angioplasty was curative in 34 (68%) symptomatic patients (posterior fossa ischemia and/or upper limb ischemia) and preventive in 16 (32%) asymptomatic patients (severe difference of blood pressure between the 2 arms and/or association with carotid stenosis or axillo-femoral bypass). Angioplasty was successful in 45 patients (primary success rate = 90%). Three (6%) thrombosis occurred due to the percutaneous approach, one of the axillary and one of the brachial artery without any significant sequelae, and one of the aorta requiring an aorto-bifemoral bypass. A complication occurred in 2 unsuccessful angioplasties (4%): an ischemic stroke occurred in 1 case and a thrombosis of the dilated site requiring a surgical bypass. Clinical follow-up over a period of 9-101 months (mean = 41) was performed in 43 out of the 45 patients who had undergone angioplasty successfully. Two patients had a follow-up shorter than 9 months: one died after 5 months, the other was lost to follow-up. By the end of the clinical follow-up, 37 (84%) out of the 44 followed-up patients had benefitted from the procedure. Doppler study performed in 35 out of the 44 followed-up patients (80%) over a period of 2-90 months (mean = 39) showed 5 restenosis (14%). This study demonstrates the good long-term results of angioplasty in case of subclavian artery stenosis. Though there are complications, angioplasty could be proposed as a first choice treatment for subclavian stenosis as compared to surgery. Indications in asymptomatic patients should be carefully weighed as complications may occur.

Percutaneous transluminal angioplasty for occlusion of the subclavian artery: short- and long-term results

Percutaneous transluminal angioplasty was performed in 8 symptomatic patients with proximal occlusion of the left subclavian artery. Technical and short-term clinical success was achieved in 7 cases. Nonoccluding embolization to the distal subclavian artery and stenosis of the brachial artery after a combined femoral/brachial approach occurred as complications in 2 patients. Three patients are asymptomatic with a patent subclavian artery 25, 28, and 37 months after angioplasty. Reobstructions in 4 patients occurring after 8, 12, and 16 months were retreated by angioplasty (3 patients) and stent implantation (1 patient with a second restenosis) with good technical and clinical success. Long-term patency was less than 50%, but successful retreatment is feasible. Therefore, we consider percutaneous transluminal angioplasty a reasonable therapeutic option in patients who are not surgical candidates.

Subclavian artery angioplasty proximal to a left internal mammary-coronary artery bypass graft: case report

Subclavian artery angioplasty is an established treatment for subclavian steal syndrome and arm ischemia caused by subclavian stenosis. We report a case of angina pectoris caused by a subclavian artery stenosis proximal to a left internal mammary-coronary artery bypass graft. Angioplasty was performed without complication and with complete relief of symptoms. Reactive hyperemia was induced in the forearm and hand with a blood pressure cuff prior to angioplasty to increase blood flow to the arm, and to reduce the chance of graft embolization. Repeat angiography 6 months later confirmed continued patency of the subclavian artery and the graft and reversal of the steal physiology. The patient remains symptom free 15 months after angioplasty.

Percutaneous transluminal angioplasty of proximal subclavian artery stenosis after left internal mammary to left anterior descending artery bypass surgery

A patient is described who underwent percutaneous transluminal angioplasty, through a brachial approach, of a high grade stenosis at the proximal portion of the left subclavian artery 1.5 years after coronary artery bypass grafting including left internal mammary to left anterior descending artery anastomosis. Symptoms of class IV angina, vertebrobasilar insufficiency and occupational arm claudication that developed after bypass surgery were promptly relieved after balloon dilation. Percutaneous transluminal angioplasty of the subclavian artery can be performed safely and provides an alternative to carotid-subclavian or axillary-axillary bypass surgery for treatment of internal mammary artery graft malfunction.

Restenosis after coronary angioplasty: a multivariate statistical model to relate lesion and procedure variables to restenosis. The M-HEART Investigators

The Multi-Hospital Eastern Atlantic Restenosis Trial group obtained follow-up angiography in 510 patients with 598 successfully dilated coronary lesions who were enrolled in a controlled trial of the effects of a single dose of 1 g of methylprednisolone on restenosis after coronary angioplasty. The overall restenosis rate was 39.6%. The strongest univariate relations to the restenosis rate were found for lesion location (saphenous vein graft, 68%; left anterior descending artery, 45%; left circumflex artery and right coronary artery, 32%; p = 0.002); lesion length (less than or equal to 4.6 mm, 33%; greater than 4.6 mm, 45%; p = 0.001); percent stenosis before angioplasty (less than or equal to 73%, 25%; greater than 73%, 43%; p = 0.005), percent stenosis after angioplasty (less than or equal to 21%, 33%; greater than 21%, 46%; p = 0.017) and arterial diameter (less than 2.9 mm, 44%; greater than or equal to 2.9 mm, 34%; p = 0.036). Two multivariate models to predict restenosis probability were developed with use of stepwise logistic regression. The preprocedural model, which included only variables whose values were known before angioplasty, entered lesion length, vein graft location, left anterior descending artery location, percent stenosis before angioplasty, eccentric lesion and arterial diameter. The postprocedural model, which also included variables whose values were known after angioplasty was performed, was similar to the preangioplasty model except that it also entered postangioplasty percent stenosis and "optimal" balloon sizing but did not enter eccentric lesion. These data indicate that the probability of restenosis after angioplasty is determined predominantly by the characteristics of the lesion being dilated. They are consistent with the known intimal proliferative mechanism of restenosis, offer a means of identifying lesions at unusually high or low risk of restenosis, and of predicting the likelihood that a particular lesion will restenose after angioplasty and provide a rationale for stratification by restenosis probability in the design of future studies of restenosis.