Thromboembolic events associated with Guglielmi detachable coil embolization with use of diffusion-weighted MR imaging. Part II. Detection of the microemboli proximal to cerebral aneurysm

BACKGROUND AND PURPOSE: The purpose of this study was to document the incidence and radiologic appearance of thromboembolic events during Guglielmi detachable coil (GDC) embolization for asymptomatic basilar artery (BA) bifurcation and BA-superior cerebellar artery (SCA) aneurysms by using diffusion-weighted (DW) MR imaging, with special emphasis on the evidence of thromboembolic events in vascular territories proximal from the treated aneurysm, which cause cerebellar infarction, and to discuss which step of the procedure (aneurysm or catheter manipulation) may play a role for most thromboembolic events. METHODS: Since 1999, 38 asymptomatic BA bifurcation and BA-SCA aneurysms were treated with GDCs at the National Cardiovascular Center. DW studies were performed for 26 patients between 2 and 5 days after GDC embolizations. All DW images were reviewed by two radiologists for depiction of abnormalities. These findings were retrospectively evaluated with clinical and technical factors of thromboembolic events. RESULTS: DW images showed new hyperintense lesions in 18 patients (69%), with seven (27%) incurring neurologic deteriorations. All symptomatic patients fully recovered by discharge. Fourteen (78%) of 18 patients showed new lesions proximal to the treated aneurysm; that is, in the cerebellar hemispheres. In three cases treated with the balloon-assisted technique, new hyperintense lesions were seen. CONCLUSION: In our experience, most thromboembolic events related to the use of the GDC embolization may be caused by catheter manipulation, especially in the case of the balloon-assisted technique. Caution should be exercised in the handling of catheters. Furthermore, a softer and smaller caliber catheter and simple GDC technique should be considered.     

Thromboembolic events associated with Guglielmi detachable coil embolization of asymptomatic cerebral aneurysms: evaluation of 66 consecutive cases with use of diffusion-weighted MR imaging

BACKGROUND AND PURPOSE: Although Guglielmi detachable coil (GDC) endovascular treatment of intracranial aneurysms has become an accepted alternative to surgery, the main complication continues to be thromboembolic events. We sought to determine the frequency and radiologic appearance of thromboembolic events during GDC embolization for asymptomatic cerebral aneurysms by using diffusion-weighted (DW) MR imaging and to determine whether aneurysmal anatomic factors or use of the balloon-assisted technique affected the frequency. METHODS: In 74 patients, 79 asymptomatic cerebral aneurysms were treated with GDC embolizations at the National Cardiovascular Center from 1999 to 2001. Thirty-nine of these aneurysms (49%) were treated with the balloon-assisted technique. DW imaging was performed in 66 patients at 2-5 days after GDC embolization. All DW images were reviewed by two radiologists for depiction of abnormalities. RESULTS: DW images showed hyperintense lesions in 40 patients (61%), with 16 of these patients (40%) incurring neurologic deteriorations. Fifteen of the symptomatic patients (94%) fully recovered by discharge, and the remaining one experienced permanent deficits. Hyperintense lesions were detected more frequently in wide-neck (73%) or large (100%) aneurysms and in procedures that used the balloon-assisted technique (73%) than in small aneurysms (50%) or in procedures with the simple GDC method (49%). The occurrence of new lesions was significantly associated with use of the balloon-assisted technique and with aneurysm diameter in multivariate analysis (P <.05). CONCLUSION: In our experience, thromboembolic events related to the use of GDC embolization are relatively common, especially in wide-neck or large aneurysms or in association with the balloon-assisted technique. Although permanent deficits are rare, the high rate of thromboembolic events suggests that improvements in the technique such as the addition of antiplatelet agents and the development of new embolic materials are mandatory.     

A case of gastrointestinal stromal tumor of the stomach

In a 55-year-old man, a tumor about 3 cm in diameter was detected in the upper abdomen by abdominal ultrasound screening during follow-up of chronic hepatitis C discovered in 1990. There were no symptoms and no abnormalities on physical examination. Tests for tumor markers were negative. By barium meal and gastroscopy, submucosal tumor was found on the lesser curvature of the stomach, with bridging fold in the absence of central ulceration. Biopsy revealed no tumor tissue. Under the diagnosis of submucosal tumor of the stomach, either a leiomyoma or leiomyosarcoma, partial resection of stomach was performed. Direct invasion of the surrounding organs, lymph node metastasis or distant metastasis was not observed grossly in the operation. Histologic examination of the resected specimen revealed proliferation of spindle cells and oval cells in an interlacing pattern. Immunohistochemistry for CD34, vimentin and c-kit protein was strongly positive, while smooth muscle actin, S-100 protein, desmin and p53 protein were negative. The proliferating cell nuclear antigen index was about 50%, while the MIB-1 index was < or = 1%. From these findings, this tumor was diagnosed as a gastrointestinal stromal tumor of the uncommitted type.     

Mesometrial smooth muscle as an origin of female retroperitoneal (pelvic) leiomyomas

Retroperitoneal (pelvic) leiomyomas have recently come to be recognized as distinctive lesions. Retroperitoneal leiomyomas occur almost exclusively in women, and past studies on these invariably emphasized a striking similarity between their histological features, with those of uterine leiomyoma, whereas their origin remains unknown. In this study, we took notice of mesometrial smooth muscle, which has been little known either clinically or pathologically, as a possible origin of tumor. Anatomically, the mesometrial smooth muscle was an accumulation of thin bundles (approximately 1 mm in thickness) that ran parallel to the oviduct. It was connected broadly with the lateral wall of the uterine body and ended in the pelvic floor. The mesometrial smooth muscle was present just beneath the serosal surface of the anterior aspect of the mesometrium and continuously transited from the smooth muscle bundles of the outer layer of the uterine myometrium. The muscle cells were immunopositive for smooth muscle cell markers and estrogen/progesterone receptors. In all of the six female retroperitoneal leiomyomas examined, hormone receptor-positive nontumorous smooth muscle layers were present in the periphery of the tumors, seemingly representing the mesometrial smooth muscles. In conclusion, we believe most retroperitoneal (pelvic) leiomyomas in females arise from the mesometrial smooth muscle.     

Factor VIII contributes to platelet-fibrin thrombus formation via thrombin generation under low shear conditions

Introduction

Thrombus growth under low blood flow velocity plays an important role in the development of deep venous thrombosis (DVT). Increased plasma levels and activities of coagulation factor VIII (FVIII) comprise risk factors for DVT and pulmonary thromboembolism.

Objective

To localize FVIII in human venous thrombi of DVT and to determine whether FVIII contributes to thrombus formation under low shear conditions.

Methods

The localization of FVIII in venous thrombi obtained from patients with DVT was examined by immunohistochemistry. The role of FVIII in thrombus formation was investigated using a flow chamber system. Venous blood from healthy volunteers were incubated with an anti-FVIII monoclonal antibody (VIII-3776) or non-immunized mouse IgG₁. Blood samples were perfused on immobilized type III collagen at wall shear rates of 70/s and 400/s and then the surface area covered by platelets and fibrin was morphometrically evaluated. Prothrombin fragment 1+2 (PF1+2) generation was measured before and after perfusion.

Results

Venous thrombi of DVT comprised a mixture of platelets, fibrin and erythrocytes. Factor VIII appeared to be colocalized with glycoprotein IIb/IIIa, fibrin and von Willebrand factor in the thrombi. VIII-3776 specifically recognized the light chain of FVIII and prolonged the activated partial thromboplastin time (aPTT), but not prothrombin time (PT). The antibody significantly reduced platelets and fibrin covering, as well as PF1+2 generation at wall shear rates of 70/s and 400/s.

Conclusions

These results suggest that FVIII contributes to platelet aggregation and fibrin formation via thrombin generation under low shear conditions.     

A radial forearm flap based on an extended dissection of the cephalic vein. The longest venous pedicle? Case report

A radial forearm flap based on the cephalic vein was elevated to resurface a defect in the left auricular region. The cephalic vein was dissected up to the clavicle and the flap was transferred through a subcutaneous tunnel to the defect. The radial artery was anastomosed to the stump of the external carotid artery using a vein graft. The flap pursued an uneventful course and survived completely. This showed that the long venous pedicle (47 cm) could drain the flap safely and sufficiently.     

Free vascularized deep peroneal neurocutaneous flap for repair of digital nerve defect involving severe finger damage

A free vascularized deep peroneal nerve graft seems to be the most suitable method for repairing digital nerve defects involving severe finger damage. We report a patient in which this graft was used as a neurocutaneous flap. The advantages of this method are its excellent vascularity, minimal functional disturbance to the donor foot, and the possibility of versatile application.     

A new dressing method for free skin grafting in hands

Using adhesive drapes and a disposable suction drain, the grafted area is compressed by positive pressure that is equivalent to the negative pressure of a suction drain. With this dressing method, the graft can be observed throughout the postoperative course, and can be applied with uniform and constant pressure. Thin drapes accommodate well to various shapes, so this method is uniquely qualified in free skin grafting of hands.     

The effect of intense arterial constriction on the survival length of an island flap; an experiment using abdominal flaps in rats

Using rats' abdominal skin flaps, the effects of markedly decreased arterial inflow was investigated. An intense constriction was created with laminated silastic tubes. Survival length of the island flap was reduced by this manipulation and the differences with the control were statistically significant. It was ascertained experimentally that the flap went into necrosis distally and progressed proximally as the arterial inflow decreased. The possible risks of the sleeve technique are also briefly described.