Cervical artery dissection (CAD) accounts for up to one fifth of ischemic strokes occurring before 45 years. Their increasing recognition is probably due to an increased clinical awareness of this condition in patients with painful ischemic events. The internal carotid artery is the most commonly affected vessel. Cerebral ischemia is the most serious consequence of a CAD. It may be due to hemodynamic factors or emboli. The enlargement of the artery may lead to a direct compression of the lower cranial nerves. CAD typically occurs in young adults with a mean age of 40 years with a male:female ratio of 1.5. After exclusion of traumatic cases, the average annual incidence rate of CAD is 2.6 per 100,000, but the reported incidence figures in the literature are likely to be an underestimation of the incidence of CAD. A spontaneous dissection is assumed when no or only minor trauma preceded the onset. However, the differentiation between spontaneous and traumatic dissections is artificial because of a continuum between both forms. The pathogenesis of dissections remains unknown in most cases. However, traumas and primary diseases of the arterial wall are the main predisposing factors. The clinical presentation of spontaneous dissections of the internal carotid artery includes cerebral ischemia, cervical or cranial pain, Homer’s syndrome and cranial nerve palsy; CAD may also be silent. Brainstem ischemic deficits and occipital pain are the most common findings in vertebral artery dissections, but these features may be biased because the most benign and the most severe cases may escape detection. The favorable natural history of CAD emphasizes the need for a noninvasive approach to the detection, monitoring and follow-up. This noninvasive approach can be obtained by means of CT scan, MRI, magnetic resonance angiography and ultrasonography, although angiography remains the gold standard for the diagnosis of arterial dissections. Follow-up studies suggest a fairly good overall prognosis in adults and in children. In many centers, CAD are treated by heparin at the acute stage, although the benefit of such a potentially dangerous treatment has never been proven by a randomized trial.
In organic MR, mitral deceleration time, mitral E/E' and left atrial volume correlate with PASP. Pulmonary artery systolic pressure > or = 50 mmHg is an independent predictor of overall and cardiovascular mortality after surgery in organic MR.
Background and Purpose-It has been shown previously that cerebral microemboli may occur frequently in patients with a normal mechanical heart valve (MHV) without prior history of stroke. Some arguments strongly suggest that these microemboli have a gaseous origin. In other circumstances such as extracorporeal circulation or decompression in divers, it has been demonstrated that cerebral microbubbles could lead to some deterioration in cognitive functions. Therefore, we have studied attention and memory, which are among the most impaired cognitive functions as demonstrated in previous studies, in patients with an MHV. Methods-Three groups of 12 volunteers each were composed of patients with an MHV and embolic signals in the cerebral circulation (group 1), patients with biological prostheses (group 2), and healthy subjects (group 3). Groups were carefully matched for age and verbal intellectual abilities. For each group, a transcranial Doppler examination was performed and a set of cognitive tests assessing sustained and selective attention and episodic and working memory was administered. Results-The mean embolic rate was 29 per hour in patients with an MHV. No embolus was detected in the other 2 groups.Episodic memory was significantly modified in both groups 1 and 2 compared with the control group for tasks that required high-processing resources. Working memory performance was significantly decreased in MHV patients. No between-groups differences were observed for the other parameters. Conclusions-Alteration of episodic memory can be attributed to a long-term effect of the surgical procedure.Deterioration of working memory can be related to the presence of cerebral microemboli in MHV patients. (Stroke. 1998;29:1821-1826.)
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