Spectrum and potential pathogenesis of reversible posterior leukoencephalopathy syndrome.

BACKGROUND: Controversy still exists over the etiology and pathophysiology of reversible posterior leukoencephalopathy syndrome (RPLS). This large single-center case series aims to describe the clinical and imaging features of RPLS in an attempt to deduce the etiology of the disorder and the mechanisms of brain injury. METHODS: A retrospective chart and imaging review was conducted on 59 cases of RPLS in 55 patients. RESULTS: Five RPLS imaging patterns were observed: posterior predominant (n = 40), anterior predominant (n = 7), diffuse lesion (n = 7), basal ganglia predominant (n = 3), and brainstem/cerebellum predominant patterns (n = 2). RPLS resulted in permanent neurologic deficits in 14 patients and death in 4 patients. Hypertension was seen in 57 (97%) cases, and mean arterial blood pressure exceeded 140 mm Hg in 30 (51%) cases. Follow-up magnetic resonance imaging scans revealed a significant worsening of vasogenic edema in 2 cases, both with persistent hypertension. Magnetic resonance imaging scans revealed areas of ischemia in 14 cases, all within or at areas closely adjacent to vasogenic edema. Diffuse vasculopathy was seen in 8 cases. There was a lack of correlation between the presence of vasculopathy and the degree of vasogenic edema (P = .62), but a correlation was suggested between ischemia and vasculopathy (P = .02). CONCLUSIONS: This study strongly suggests that hypertension-induced vasodilation rather than vasoconstriction-mediated hypoxia is likely the major mechanism responsible for the development of vasogenic edema, and that vasoconstriction may contribute to the development of ischemia in RPLS.

Strokes after cardiac surgery and relationship to carotid stenosis.

OBJECTIVE: To critically examine the role of significant carotid stenosis in the pathogenesis of postoperative stroke following cardiac operations. DESIGN: Retrospective cohort study. SETTING: Single tertiary care hospital. PARTICIPANTS: A total of 4335 patients undergoing coronary artery bypass grafting, aortic valve replacement, or both. MAIN OUTCOME MEASURES: Incidence, subtype, and arterial distribution of stroke. RESULTS: Clinically definite stroke was detected in 1.8% of patients undergoing cardiac operations during the same admission. Only 5.3% of these strokes were of the large-vessel type, and most strokes (76.3%) occurred without significant carotid stenosis. In 60.0% of cases, strokes identified via computed tomographic head scans were not confined to a single carotid artery territory. According to clinical data, in 94.7% of patients, stroke occurred without direct correlation to significant carotid stenosis. Undergoing combined carotid and cardiac operations increases the risk of postoperative stroke compared with patients with a similar degree of carotid stenosis but who underwent cardiac surgery alone (15.1% vs 0%; P = .004). CONCLUSIONS: There is no direct causal relationship between significant carotid stenosis and postoperative stroke in patients undergoing cardiac operations. Combining carotid and cardiac procedures is neither necessary nor effective in reducing postoperative stroke in patients with asymptomatic carotid stenosis.