Intraluminal thrombus in the carotid artery is often misdiagnosed because clinical imaging, such as angiography and duplex ultrasonography, fails to accurately identify it. Recently, it was reported that optical coherence tomography (OCT), a new imaging modality, can visualize intravascular thrombus in the coronary artery.An 83-year old male was admitted due to newly developed motor weakness of the left hand. Diffusion weighted magnetic resonance imaging showed multiple high intensity spots in the territory of the right middle cerebral artery, and magnetic resonance angiography revealed significant stenosis at the origin of the right internal carotid artery. Because of an apparent change in plaque shape on the angiogram just before carotid artery stenting, further examinations such as intravascular ultrasonography (IVUS) and OCT were performed.After IVUS examination, both the common carotid and external carotid arteries were occluded by an occlusion balloon system prepared for carotid artery stenting. Then the stenotic site was imaged by OCT from the distal section at 1 mm/sec using a built-in pull-back system with continuous injection of saline through the guiding catheter to remove blood from the field of view. Since intraluminal thrombus was clearly demonstrated by an OCT, carotid endarterectomy was performed instead of stenting, and thrombus was confirmed by surgical specimen.OCT may provide useful information for diagnosis of an intraluminal thrombus in the carotid artery, which is important for the appropriate selection of therapeutic strategy.
OCT has been reported as a high-resolution imaging tool for characterizing plaque in the coronary arteries. The present study aimed to evaluate the ability of OCT to visualize carotid artery plaques compared with that of IVUS in asymptomatic and symptomatic patients.
MATERIALS AND METHODS:
OCT was performed for 34 plaques (17 symptomatic, 17 asymptomatic) in 30 patients during CAS under a proximal cerebral protection method. OCT was performed before balloon angioplasty and after stent placement. IVUS was also performed just after OCT.
RESULTS:
No technical or neurologic complications were encountered by using OCT. An inner catheter was used in 12 of 34 procedures (35.3%) for advancing the OCT image wire beyond the site of stenosis. OCT clearly visualized intraluminal thrombus in 15 of 34 plaques (44.1%), whereas IVUS detected a thrombus in 1 plaque (2.9%, P < .001). Neovascularization was demonstrated in 13 of 34 plaques (38.2%) by OCT, but not by IVUS (0%, P < .001). Intraluminal thrombus was more frequently observed in symptomatic plaques (13 of 17, 76.5%) than in asymptomatic plaques (2 of 17, 11.8%; P < .001). Interobserver and intraobserver variability with OCT diagnosis was excellent for thrombus, ulceration, neovascularization, and lipid pool.
CONCLUSIONS:
The present findings suggest that OCT can safely and precisely visualize human carotid plaques during CAS and that intraluminal thrombus and neovascularization are more frequently detected in symptomatic plaques.
In Japan, pulmonary thromboembolism (PTE) is rare and the therapy of this disease, especially the thrombolytic therapy, has not been established yet. We studied the effect of thrombolytic therapy by urokinase (UK) in eighteen patients with PTE. We also compared the results with those in Europe and the United States. Eighteen patients (male 7, female 11) were 27 yo to 77 yo (mean 55 yo). Seven cases were mild and 11 cases were moderate to severe. The initial dosage of UK administration was 2.4 x 10(5) to 7.2 x 10(5) IU with the mean of 4.1 x 10(5) IU, which was approximately the double of those in Europe and the US. The duration of UK therapy was 1 to 9 days with the mean of 4.8 days. It was longer than in Europe and the US (12-24 hours). Total amount of UK in each case ranged 4.8 x 10(5) to 42 x 10(5) IU (mean 19.3 x 10(5) IU) with the daily dosage of 4.0 x 10(5) IU in average. They were almost half of those in Europe and the US. Clinical signs and laboratory findings subsided in 1-7 day by UK administration in 14 cases (87%) with the reduction of defects on perfusion lung scans and all of these cases survived. No severe complications were found in any cases. We conclude that the thrombolytic therapy with UK in Japan might be acceptable from the results of this present study. However, the prospective study of thrombolytic therapy on a larger scale remains to be done in the future.
Lindera strychnifolia (Tendai-Uyaku), a medicinal plant, has long been used for the treatment of cardiac, renal and rheumatic diseases in Japan. We investigated the effect of Lindera strychnifolia on systolic blood pressure, cardiac function, and plasma noradrenaline levels in rats. Spontaneously hypertensive rats (SHR) were given free access to water or extract solution of Lindera strychnifolia, which was extracted with a ratio of 10 g Lindera strychnifolia roots/20 ml water. Systolic blood pressure was measured by using a tail-cuf sphygmomanometer twice a week from 10 to 30 weeks of age, and compared to the age-matched Wistar Kyoto rats (WKY) as a control group. At 30 weeks of age, heart function was measured by echocardiography and blood samples were taken for detection of plasma noradrenaline levels, and rats were then sacrificed. Systolic blood pressure gradually increased from 10 to 30 weeks of age in the SHR group, while it did not change in the WKY group. In the Lindera-treated SHR group, the increase in systolic blood pressure was significantly attenuated from 21 to 30 weeks of age. Echocardiography showed a significant increase in ejection fraction in the Lindera-treated SHR group (60.4 ± 7.8%) as compared to the SHR group (39.7 ± 23.4%). Plasma noradrenaline levels were significantly decreased in Lindera-treated SHR group compared to the SHR group. These results suggest that Lindera strychnifolia has an anti-hypertensive effect and improves cardiac function in spontaneous hypertensive rats. These effects may be related to the decrease in plasma noradrenaline levels by Lindera strychnifolia.
