A possible relationship between abortions and placental embolism in pregnant rabbits given human granulocyte colony-stimulating factor. (41/776)

Developmental toxicity studies were conducted in rats and rabbits with a human G-CSF derivative (NTG). As reported for G-CSF, increases in abortions and fetal mortality were observed in rabbits, but not in rats given NTG. Histopathological examination of the rabbit placenta revealed accumulation of neutrophils in vessels and necrosis of the tissues surrounding these vessels. To assess the mechanism of abortion and fetal death in rabbits given G-CSF, 125I-labeled NTG was given intravenously on Day 18 of pregnancy after repeated administration of cold NTG on Days 6 through 17 of pregnancy, and the feto-maternal distribution of radioactivity was examined. In a rabbit given 20 micrograms/kg, high radioactivity was observed in the endometrium, placenta, and some parts of the decidua at 6 hr when the concentration of radioactivity in maternal blood had already decreased. At 24 hr after administration of 200 micrograms/kg NTG, high radioactivity was still detected in parts of the maternal placenta. These patterns of distribution suggest that embolism occurred in parts of the uterus and placenta which might have caused congestion. Radioactivity in the TCA precipitates in the fetus was low, suggesting that NTG does not readily transfer to the fetus. These results strongly suggest that neutrophils accumulated in the vessels of placenta and induced embolism leading to abortions and fetal mortality in the rabbits given G-CSF.  (+info)

Echocardiography predicts embolic events in infective endocarditis. (42/776)

OBJECTIVES: The aim of our study was to assess the value of transesophageal echocardiography (TEE) in predicting embolic events (EEs) in a large group of patients with definite endocarditis according to the Duke criteria, including silent embolism. BACKGROUND: The value of echocardiography in predicting embolism in patients with endocarditis remains controversial. Some studies reported an increased risk of embolism in patients with large and mobile vegetations, whereas other studies failed to demonstrate such a relationship. METHODS: Multiplane transesophageal echocardiograms of 178 consecutive patients with definite infective endocarditis (IE) were analyzed. The incidence of embolism was compared with the echocardiographic characteristics (localization, size and mobility) of the vegetations. To detect silent embolism, cerebral and thoraco-abdominal scans were performed in 95% of patients. RESULTS: Among 178 patients, 66 (37%) had one or more EEs. There was no difference between patients with and without embolism in terms of age, gender and left valve involved. On univariate analysis, Staphylococcus infection, right-side valve endocarditis and vegetation length and mobility were significantly related to EEs. A significant higher incidence of embolism was present in patients with vegetation length >10 mm (60%, p < 0.001) and in patients with mobile vegetations (62%, p < 0.001). Embolism was particularly frequent among 30 patients with both severely mobile and large vegetations (> 15 mm) (83%, p < 0.001). On multivariate analysis, the only predictors of embolism were vegetation length (p = 0.03) and mobility (p = 0.01). CONCLUSIONS: Our study shows that the presence of vegetations on TEE is predictive of embolism and that the morphologic characteristics of vegetations are helpful in predicting EEs in both mitral and aortic valve IE. It also suggests that early operation may be recommended in patients with vegetations > 15 mm and high mobility, irrespective of the degree of valve destruction, heart failure and response to antibiotic therapy.  (+info)

Atheromatous plaque in the distal aortic arch creating the potential for cerebral embolism during cardiopulmonary bypass. (43/776)

The present study evaluated the risk in cardiac patients of rupture of a plaque by a jet stream from the arch cannula. The entire thoracic aorta and cardiac function were routinely monitored by transesophageal echocardiography (TEE) in 88 adult patients who underwent coronary artery bypass surgery. The changes in the atheromatous plaque in the distal aortic arch were observed before and after cardiopulmonary bypass. Of the 88 patients, 13 were found to have preoperative atheromatous plaque at the distal aortic arch and 8 (61.5%) of them suffered plaque rupture caused by jet stream from the arch cannula. Only 1 patient experienced apparent embolic episodes manifesting as cerebral and left leg embolisms; the remaining 7 had no clinical embolic symptoms. In order to prevent atheroembolic events, attention should be paid not only to the ascending aorta, but also to the distal arch and in this regard TEE is useful for detecting atheromatous changes of the aorta.  (+info)

Short-term outcome of stent implantation in saphenous vein grafts: predictors of distal embolization and restenosis. (44/776)

The present study, which aimed to determine the predictors of distal embolization and restenosis after stenting for vein graft disease, retrospectively analyzed 51 consecutive patients who underwent stent implantation for diseased saphenous vein grafts. Follow-up angiography was performed 6 months after the procedure and the clinical and angiographic variables were analyzed by multivariate logistic regression to determine the predictors of distal embolization and restenosis. Initial clinical success was achieved in 49 patients, 44 of whom underwent follow-up angiography and were enrolled in the retrospective analysis. Distal embolization occurred in 6 grafts (13.6%). Multivariate analysis showed that the lesion length and the total cholesterol level were independent predictors of distal embolization. Angiographic restenosis occurred in 13 (26.5%) of 49 lesions. The minimum luminal diameter and the percent diameter stenosis after stenting were associated with the occurrence of restenosis. Multivariate analysis of lesions located in the graft body identified graft age as an independent predictor of restenosis. Distal embolization can occur after vein graft stenting, especially in patients with hypercholesterolemia and diffuse stenosis. The post-stenting minimum luminal diameter and the percent diameter stenosis are predictors of restenosis. In particular, graft age is associated with the restenosis of graft body lesions.  (+info)

Randomized trial of vein versus Dacron patching during carotid endarterectomy: influence of patch type on postoperative embolization. (45/776)

PURPOSE: A recent overview indicated that although routine patching is safer than routine primary closure after carotid endarterectomy (CEA), there is no systematic evidence that patch type influences outcome. However, most surgeons still believe that prosthetic patches are probably more thrombogenic than vein patches. This study tested the hypothesis that there was no difference in thrombogenicity between the different patch types. METHODS: A total of 274 patients undergoing 276 CEAs were randomized to either Dacron-patch closure (n = 137) or vein-patch closure (n = 139). All patients with an accessible cranial window were monitored for 3 hours postoperatively with transcranial Doppler scanning (TCD). The number of emboli and rate of embolization were quantified with the requirement for selective dextran therapy to control high rates of postoperative embolization. All patients were assessed postoperatively and again at 30 days by a neurologist, and all patients underwent a duplex examination at 30 days. RESULTS: The 30-day death/any stroke rate was 2.2% for patients in the Dacron-patch group and 3.6% for patients in the vein-patch group (P =.72). Patients in the Dacron-patch group had a higher incidence of postoperative emboli (median, 5; interquartile range, 0-10.5) than patients in the vein-patch group (median, 3; interquartile range, 1-17; P =.028). However, the incidence of detecting more than 50 emboli was virtually identical, and patch type had no effect on the incidence of high-rate, sustained embolization that required dextran therapy (5.3% for Dacron, 3.7% for vein). No patient had a carotid thrombosis at 30 days. CONCLUSION: Sustained, high-rate embolization, previously shown to be highly predictive of progression to carotid thrombosis, appears to be patient dependent, rather than related to patch type.  (+info)

Use of transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation. (46/776)

BACKGROUND: The conventional treatment strategy for patients with atrial fibrillation who are to undergo electrical cardioversion is to prescribe warfarin for anticoagulation for three weeks before cardioversion. It has been proposed that if transesophageal echocardiography reveals no atrial thrombus, cardioversion may be performed safely after only a short period of anticoagulant therapy. METHODS: In a multicenter, randomized, prospective clinical trial, we enrolled 1222 patients with atrial fibrillation of more than two days' duration and assigned them to either treatment guided by the findings on transesophageal echocardiography or conventional treatment. The composite primary end point was cerebrovascular accident, transient ischemic attack, and peripheral embolism within eight weeks. Secondary end points were functional status, successful restoration and maintenance of sinus rhythm, hemorrhage, and death. RESULTS: There was no significant difference between the two treatment groups in the rate of embolic events (five embolic events among 619 patients in the transesophageal-echocardiography group [0.8 percent]) vs. three among 603 patients in the conventional-treatment group [0.5 percent], P=0.50). However, the rate of hemorrhagic events was significantly lower in the transesophageal-echocardiography group (18 events [2.9 percent] vs. 33 events [5.5 percent], P=0.03). Patients in the transesophageal-echocardiography group also had a shorter time to cardioversion (mean [+/-SD], 3.0+/-5.6 vs. 30.6+/-10.6 days, P<0.001) and a greater rate of successful restoration of sinus rhythm (440 patients [71.1 percent] vs. 393 patients [65.2 percent], P=0.03). At eight weeks, there were no significant differences between the two groups in the rates of death or maintenance of sinus rhythm or in functional status. CONCLUSIONS: The use of transesophageal echocardiography to guide the management of atrial fibrillation may be considered a clinically effective alternative strategy to conventional therapy for patients in whom elective cardioversion is planned.  (+info)

L-arginine and S-nitrosoglutathione reduce embolization in humans. (47/776)

BACKGROUND: L-Arginine reduces platelet aggregation and adhesion in ex vivo studies, but there is no evidence as yet that it has a therapeutic effect on clinical end points. Doppler ultrasound can detect cerebral emboli noninvasively. Such embolic signals are common after carotid endarterectomy, and their frequency predicts risk of stroke recurrence. We used this situation to determine the antiplatelet efficacy of L-arginine and S-nitrosoglutathione (GSNO), a physiological nitric oxide donor with possible platelet specificity. METHODS AND RESULTS: Patients undergoing carotid endarterectomy were randomized in a double-blind manner between L-arginine (n=14), GSNO (n=14), or placebo (n=14) administered intravenously for 90 minutes, starting 30 minutes after skin closure. All patients were pretreated with aspirin and given heparin during surgery. Transcranial Doppler recordings were made from the ipsilateral middle cerebral artery for 4 hours after surgery, beginning 30 minutes after skin closure, and also at 6 and 24 hours. There were highly significant reductions in the number of Doppler embolic signals in the L-arginine and GSNO groups; first 4 hours, median (range) number of embolic signals, placebo 44.7 (6 to 778), L-arginine 9.5 (0 to 225), and GSNO 0.8 (0 to 8), both P<0.001 versus control values. The reduction in the signals persisted at the 24-hour recording. CONCLUSIONS: Intravenous L-arginine and GSNO attenuate Doppler embolic signals in humans. Modulation of the NO system with these agents may have applications in the treatment of thromboembolic disease. This study demonstrates the potential application of ultrasonic embolic signal detection to examine the efficacy of new antiplatelet agents in relatively small numbers of patients.  (+info)

Current perspective on the role of apoptosis in atherothrombotic disease. (48/776)

Thrombus formation on a disrupted atherosclerotic plaque is a threatening event that leads to vessel occlusion and acute ischemia. In this current perspective, we present evidence for apoptosis as a major determinant of the thrombogenicity of the plaque lipid core and a potential contributor to plaque erosion and associated thrombosis. Moreover, apoptosis may directly affect blood thrombogenicity through the release of apoptotic cells and microparticles into the bloodstream.  (+info)