Basilar Artery Occlusive Disease in the New England Medical Center Posterior Circulation Stroke Registry

P57 Most reports on basilar artery (BA) occlusive disease have retrospectively described isolated cases or small series of patients, focusing mainly on clinicoanatomical correlations. To assess the stroke mechanisms, etiologies, clinical and vascular features, and outcome of BA occlusive disease, we analyzed 76 patients (52 men, 24 women; mean age: 62.1 yrs; range: 5 - 87 yrs) prospectively collected in the New England Medical Center Posterior Circulation Stroke Registry between November 1986 and February 1997, with a diagnosis of moderate (50–70%) to severe (>70%) BA stenosis or occlusion. Vascular imaging was done by TCD, catheter angiography or MRA. BA stenosis was found in 51 (67.1%) patients, while 25 (32.9%) had BA occlusion. Most patients (60.5%) had involvement of the mid-portion of the BA. In 44.7% of patients, the occlusive disease was intrinsic to the BA, in 43.4% BA involvement was part of extensive atherosclerosis in the posterior circulation, and 11.8% of patients had embolism to the BA from the heart or proximal arteries. Fifty-two patients (68.4%) had strokes, half preceded by TIAs. The remaining 24 patients presented with TIAs only. The average duration of TIAs was 3.7 months, when excluding 4 patients whose TIAs lasted over 8 yrs. When an infarct was present, the middle posterior intracranial territory including the pons and the anteroinferior cerebellum was most often involved (73.1%). The etiology of the BA lesions was atherothrombotic in 77.6% and the mechanism presumed hemodynamic in 73.7%. Hypertension (64.5%), hyperlipidemia (40.8%) and coronary artery disease (35.5%) were the most frequent risk factors. Among the 9 patients without risk factors, 3 had BA dissections and 2 had basilar migraine. Of patients with a BA stenosis, 50% had no deficits at follow-up, whereas 75% of BA occlusions lead to disability. Embolism to the BA had severe outcome, with major disability or death occurring in 77.8% of patients. The outcome was best in the patients with diffuse atherosclerotic disease. Our data shows that studying the clinical and vascular features helps understand the mechanism, etiology and determine outcome in BA occlusive disease.