Patent foramen ovale is not associated with an increased risk of stroke recurrence.

BACKGROUND AND PURPOSE: Despite numerous studies suggesting a relationship between paradoxical embolism from a patent foramen ovale (PFO) and stroke, the role of PFO as a risk factor for cerebral ischaemia remains controversial. We therefore sought to determine the association between a RLS detected by contrast-enhanced transcranial Doppler ultrasonography (c-TCD) and recurrent stroke in an unselected population sample. METHODS: We analyzed the records of 763 patients with diagnosis of cerebral ischaemia at our institution. All patients had undergone TCD-based detection of RLS. Embolic signals have been measured both under resting conditions and after performing a Valsalva maneuver. For follow-up, all patients were contacted by mail, which included a standardized questionnaire. Endpoints of follow-up were defined as recurrence of cerebral ischaemia, occurrence of myocardial infarction or death from any cause. RESULTS: Follow-up data were available in 639 patients (83.7%). At baseline, a RLS was detected in 140 (28%) men and in 114 (42%) women. Ten shunt-carriers (1.6%) and 32 patients (5.0%) without RLS had suffered a recurrent stroke. After adjustment for age, sex, and atrial fibrillation, the hazard ratio of RLS for stroke recurrence was 0.86 (95% CI 0.41-1.79). The condition of RLS at rest adjusted for age, sex, stroke subtype, and cardiovascular risk factors was not found to increase the risk of stroke substantially (HR 1.16 [95% CI 0.41-3.29]) CONCLUSION: Our data suggest that the risk of recurrent stroke in subjects with PFO is not significantly increased in comparison with subject without it.

MRI plaque imaging reveals high-risk carotid plaques especially in diabetic patients irrespective of the degree of stenosis.

BACKGROUND: Plaque imaging based on magnetic resonance imaging (MRI) represents a new modality for risk assessment in atherosclerosis. It allows classification of carotid plaques in high-risk and low-risk lesion types (I-VIII). Type 2 diabetes mellitus (DM 2) represents a known risk factor for atherosclerosis, but its specific influence on plaque vulnerability is not fully understood. This study investigates whether MRI-plaque imaging can reveal differences in carotid plaque features of diabetic patients compared to nondiabetics. METHODS: 191 patients with moderate to high-grade carotid artery stenosis were enrolled after written informed consent was obtained. Each patient underwent MRI-plaque imaging using a 1.5-T scanner with phased-array carotid coils. The carotid plaques were classified as lesion types I-VIII according to the MRI-modified AHA criteria. For 36 patients histology data was available. RESULTS: Eleven patients were excluded because of insufficient MR-image quality. DM 2 was diagnosed in 51 patients (28.3%). Concordance between histology and MRI-classification was 91.7% (33/36) and showed a Cohen's kappa value of 0.81 with a 95% CI of 0.98-1.15. MRI-defined high-risk lesion types were overrepresented in diabetic patients (n = 29; 56.8%). Multiple logistic regression analysis revealed association between DM 2 and MRI-defined high-risk lesion types (OR 2.59; 95% CI [1.15-5.81]), independent of the degree of stenosis. CONCLUSION: DM 2 seems to represent a predictor for the development of vulnerable carotid plaques irrespective of the degree of stenosis and other risk factors. MRI-plaque imaging represents a new tool for risk stratification of diabetic patients.

Lesion patterns in patients with cryptogenic stroke with and without right-to-left-shunt.

BACKGROUND AND PURPOSE: Despite numerous studies, the role of patent foramen ovale (PFO) as a risk factor for stroke due to paradoxical embolism is still controversial. On the assumption that specific lesion patterns, in particular multiple acute ischaemic lesions on diffusion-weighted magnetic resonance imaging, indicate a cardioembolic origin, we compared the MRI findings in stroke patients with right-to-left shunt (RLS) and those without. METHODS: The records of 486 patients with diagnosis of cerebral ischaemia were reviewed. For detection of RLS, contrast-enhanced transcranial Doppler (c-TCD) was carried out in all patients. An MRI scan of the brain was performed in all patients. Affected vascular territories were divided into anterior cerebral artery, middle cerebral artery, vertebrobasilar artery system including posterior cerebral artery, brain stem and cerebellar stroke, and strokes occurring in more than one territory. RESULTS: We did not find a specific difference in neuroradiological lesion patterns in patients with RLS compared with patients without RLS. In particular, 23 of 165 patients (13.9%) with RLS showed multiple ischaemic lesions on MRI in comparison with 45 of 321 patients (14.0%) without RLS (P = 0.98). These findings also applied for the subgroup of cryptogenic strokes with and without RLS. CONCLUSION: We found no association between an ischaemic lesion pattern that is considered as being typical for stroke due to cardiac embolism and the existence of PFO. Therefore, our findings do not provide any support for the common theory of paradoxical embolism as a major cause of stroke in PFO carriers.