Endovascular Therapy of Symptomatic Innominate-Subclavian Arterial Occlusive Lesions

The objective was to assess the prevalence of subclavian artery stenosis (SS) in four cohorts (two free-living and two clinical populations) and determine both risk factors for this condition and the association with other cardiovascular conditions. The prevalence of SS in the general population is unknown, and its association with risk factors and other cardiovascular diseases is not well-established. A total of 4,223 subjects (2,975 from two free-living cohorts and 1,248 from two clinical cohorts) were included in this cross-sectional analysis. Subclavian artery stenosis was defined as > or =15 mm Hg interarm pressure difference. The prevalence of SS was 1.9% in the free-living cohorts and 7.1% in the clinical cohorts; SS was significantly (p < 0.05) associated with past smoking (odds ratio [OR] = 1.80), current smoking (OR = 2.61), and higher levels of systolic blood pressure (OR = 1.90 per 20 mm Hg). Higher levels of high-density lipoprotein (HDL) cholesterol were inversely and significantly associated with SS (OR = 0.87 per 10 mg/dl). In regression analyses relating SS to other cardiovascular diseases, the only significant finding was with peripheral arterial disease (PAD) (OR = 5.11, p < 0.001). Significant SS is present in approximately 2% of the free-living population and 7% of the clinical population. Additionally, SS is correlated with current and past smoking histories, systolic blood pressure, HDL levels (inversely), and the presence of PAD. These findings suggest that bilateral brachial blood pressure measurements should routinely be performed in patients with an elevated risk profile, both to screen for SS, and to avoid missing a hypertension or PAD diagnosis because of unilateral pressure measurement in an obstructed arm.

Atrial fibrillation and severe carotid-artery stenosis are well-characterised risk factors for stroke; each is present in about a fifth of patients. The identification of such risk factors in patients is important because their presence calls for specific secondary prevention strategies. One region of the circulation that has received limited attention as a source of thrombus is the aortic arch. However, aortic arch atheroma is a common post-mortem finding, and it seems reasonable to speculate that atheroma might give rise to thrombi with distal embolism to the arterial tree, including the cerebral circulation. Here we review the evidence for aortic-arch atheroma as an important independent risk factor for stroke, and show that studies of the risk of stroke indicate a four times greater odds of stroke in patients with severe arch atheroma.

Percutaneous transluminal angioplasty (PTA) is one of the treatment options for localized obstruction of the subclavian artery. To document long-term durability of this kind of PTA we report a 10-year single-center experience in 110 patients. From January 1993 to July 2003, 110 patients (72 women; mean age, 62 +/- 10 years) underwent PTA of symptomatic (>75%) stenosis (n = 90) or occlusion of the proximal subclavian artery (84 left-sided). Forty one patients (37%) had symptoms of vertebrobasilar insufficiency, 29 patients (26%) had disabling chronic arm ischemia, and 20 patients had both symptoms. Twenty patients with coronary artery disease underwent PTA in preparation for myocardial revascularization with the internal mammary artery. Duplex scans and arteriograms confirmed significant stenosis or occlusion. All PTA procedures were performed with the patient under local anesthesia, through the femoral artery (n = 89), brachial artery (n = 6), or combined route (n = 15). In 59 patients (58%) an additional stent was placed. Angioplasty was initially technically and clinically successful in 102 patients (93%). Seven occlusions could not be recanalized, and 1 procedure had to be stopped because of ischemic stroke. Of the 102 patients in whom treatment was successful, 1 patient (1%) had a minor stroke in the contralateral hemisphere 2 hours post-PTA. Seven patients (7%) had minor problems, all without permanent sequelae. Follow-up with duplex scanning ranged from 3 months to 10 years (mean, 34 months). Primary clinical patency at 5 years was 89%, with a median recurrent obstruction-free period of 23 months. The local complication rate was 4.5%, and the combined stroke and death rate was 3.6%. Significant recurrent obstruction (>70%) developed in 8 patients with clinical symptoms. Four stenoses were successfully treated with repeat PTA (2 with additional stent placement); 4occlusions required surgery. PTA of obstructive lesions of the proximal subclavian artery is not only an effective initial treatment, but is also successful over the long-term. Inasmuch as all clinical failures occured within 26 months after initial therapy, we recommend regular follow-up for at least 2 years post-PTA. All clinically significant recurrent stenoses can be treated with repeat endovascular procedures. We could not prove positive or negative influence of additional placement of stents; however, the number of recurrent stenoses might be too small in this retrospective study to draw firm conclusions. Adverse events of any kind are certainly no greater than with invasive surgical procedures. Therefore PTA must be seriously considered in patients with localized obstruction of the proximal subclavian artery.