Biomedical subjects

Wei Zhou

Publications and source records attributed to Wei Zhou.

244 records · Page 14Linked to original sources

PubMedDate not supplied

Evaluation of lenticonus in Alport's syndrome: quantitative Scheimpflug analysis.

Anterior lenticonus is an ocular abnormality that can occur in Alport's syndrome. In this study, Scheimpflug slit imaging analyses were employed for quantitative and objective evaluation of lens changes associated with Alport's syndrome. It was determined that while the apices of the lenticular protrusions are central in the vertical plane, they are nasally displaced in the horizontal meridian. The eccentricity and dimensions of the diameters and thicknesses of the conical aberration are highly correlated in both eyes. Lens thickness and anterior chamber depth do not differ between eyes. Densitometrically similar differences are apparent in the cortex and nuclear regions although evidence of overt opacification may or may not be present. The data strongly suggest that the physical parameters of the lenticonus are consistent with the constraints imposed by the pupil. Changes observed in the cornea and the vitreous may be associated with the syndrome.

Adult↗

PubMedDate not supplied

Fine needle aspiration of splenic extramedullary hematopoiesis presenting as a solitary mass. A case report.

BACKGROUND: Extramedullary hematopoiesis (EMH) generally occurs in patients with deficient bone marrow hematopoiesis secondary to either peripheral red cell destruction or marrow replacement. EMH is most commonly seen in the liver and spleen as a diffuse lesion. Rarely EMH presents as a solitary mass, posing a diagnostic dilemma. In asymptomatic patients without obvious evidence of hematopathology, the differential diagnosis is even more complex. Despite the several articles detailing the radiographic findings in EMH, fewer promote the utility of fine needle aspiration (FNA) in making this diagnosis. CASE: EMH presented as a discrete, 6-cm, tumorlike splenic mass, first identified on computed tomography in a patient with a history of prostate carcinoma. FNA findings suggested a diagnosis of EMH, which was confirmed by splenectomy. In searching for the cause of EMH, no evidence of either metastatic or hematologic disease was identified. The cause of EMH in this patient remains unknown. To our knowledge, this is the first case of solitary splenic EMH reported to occur in an asymptomatic patient. CONCLUSION: FNA is a useful adjunct in the evaluation of isolated splenic masses, particularly in the diagnosis of EMH, where hematopoietic precursors are readily identified cytologically. We advocate the use of FNA in the management of splenic masses. In addition, our case also suggests that EMH be included in the differential diagnosis of isolated splenic lesions, even in patients without obvious hematologic disorders.

Biopsy, Needle↗

PubMedDate not supplied

Treatment options of iatrogenic pelvic vein injuries: conventional operative versus endovascular approach--case reports.

Iatrogenic injury to the iliac vein or inferior vena cava (IVC), which may occur during abdominal operations or posterior orthopedic procedures, can have devastating consequences. Operative management is challenging and may be associated with significant morbidity. The authors report herein 3 cases of iatrogenic pelvic vein injuries that were managed with different treatment approaches. Both traditional open surgical therapy and endovascular techniques are described.

Adult↗

PubMedDate not supplied

Laser atherectomy for lower extremity revascularization: An adjunctive endovascular treatment option.

Excimer laser atherectomy (LA) employs precision laser energy control (shallow tissue penetration) and safer wavelengths (ultraviolet as opposed to the infrared spectra in older laser technology), which decreases perforation and thermal injury to the treated vessels. Though extensively used by cardiologists for severe obstructive coronary artery disease, peripheral interventionalists have not accepted LA as a routine adjunctive technique for stenotic or occluded vessels. We report herein the technical and clinical outcomes with LA for complex peripheral vascular disease in patients deemed high-risk for conventional surgical revascularization. Over a 6-month period, 19 lesions in 15 high-risk patients (mean age 72 +/-10 years) were treated with LA (308-nm spectral wavelength) followed by balloon angioplasty for limb-threatening ischemia (n = 10) and severe disabling claudication (n = 5). The lesions were located at the superficial femoral artery (n = 8), popliteal artery (6), and/or tibial vessels (5). The mean occlusion length was 10.3 +/-2.3 cm. Laser catheter choice ranged from 1.4 to 2.5 mm depending on the target vessel diameter. Clinical examination, duplex ultrasound, and ankle-brachial indices were performed in follow-up visits. Immediate technical success was achieved in 16 (84%) lesions. In the 3 technical failures, inability to cross the lesion with a wire (n = 2) or vessel perforation (n = 1) precluded successful LA. Overall, primary patency as assessed by duplex was 57% (superficial femoral artery 71%, popliteal 60%, tibial vessels 25%). Clinical improvement was seen in 10 lesions (77%) that were successfully treated initially. One patient required below-knee amputation. At an average of 2-year follow-up, 6 patients who were initially successfully treated were alive (46%), including 3 patients (50%) with stable symptoms without the need for major amputation. Laser atherectomy is a useful adjunctive revascularization technique for high-risk patients with limb-threatening ischemia. This technique is especially beneficial in the treatment of ostial lesions, which may be prone to distal embolization, as well as total occlusions that can be traversed by a guide wire but not a balloon. Vascular surgeons should add LA to their endovascular armamentarium for the treatment of complex peripheral vascular disease in the high surgical risk patients. Further study of clinical outcome measures and comparison to other interventional techniques are warranted.

Aged↗

PubMedDate not supplied

Use of parietal peritoneum for aortic stump coverage following removal of an infected aortic prosthesis: A case report.

Aortic graft infections, albeit rare, pose a significant treatment challenge. Aortic stump disruption, in particular, is a potentially devastating complication. We describe a novel technique of using the parietal peritoneum to bolster a friable aortic stump in a 56-year-old man after an infected aortobifemoral graft was removed. The parietal peritoneal pedicle, in our experience, provides an effective alternative to reinforce an aortic stump when conventional coverage options have been exhausted.

Aorta, Abdominal↗

PubMedDate not supplied

Successful surgical management of pelvic congestion and lower extremity swelling owing to absence of infrarenal inferior vena cava.

Absence of isolated infrarenal inferior vena cava (IVC) is a rare condition documented in only a few published cases and typically treated with anticoagulation. We herein describe successful surgical management of the isolated infrarenal IVC absence in a healthy 35-year-old woman who presented with disabling pelvic congestion. An ascending venogram showed the absence of infrarenal IVC with a large left ovarian vein draining pelvic collateral vessels to the normal left renal vein and suprarenal IVC. The patient was successfully treated with a common femoral vein to the suprarenal IVC bypass using a bifurcated polytetrafluoroethylene graft, with rapid symptom resolution, and remained symptom free 6 months later. This is the first reported case describing a surgical strategy for isolated infrarenal IVC absence in a symptomatic patient.

Adult↗

PubMedDate not supplied

Utility of retrievable vena cava filters and mechanical thrombectomy in the endovascular management of acute deep venous thrombosis.

Endovascular interventions of symptomatic deep venous thrombosis (DVT) using various therapeutic modalities, such as thrombolysis, mechanical thrombectomy, and inferior vena cava (IVC) filter placement, have received increased focus owing in part to advances in catheter-based interventional technologies. Although systemic anticoagulation remains the primary treatment modality in DVT, catheter-based interventions can provide rapid removal of large thrombus burden and possibly preserve venous valvular function in patients with symptomatic DVT. This article reviews current endovascular treatment strategies for acute DVT. Specifically, the utility of mechanical thrombectomy along with various temporary IVC filters in the setting of DVT is examined. Lastly, an illustrative case of acute DVT that was treated with endovascular intervention with IVC filter placement is presented.

Acute Disease↗

PubMedDate not supplied

Carotid artery stenting with distal protection using the carotid wallstent and filterwire neuroprotection: single-center experience of 380 cases with midterm outcomes.

Emerging data have supported the clinical efficacy of carotid artery stenting (CAS) in stroke prevention in high-risk surgical patients. This study was performed to evaluate the midterm clinical outcome of CAS using the Carotid Wallstent and FilterWire distal protection (both Boston Scientific, Natick, MA) at an academic institution. Risk factors for in-stent restenosis (ISR) were also analyzed. Clinical variables and treatment outcome of high-risk patients who underwent Carotid Wallstent placement with FilterWire EX/EZ neuroprotection were analyzed during a recent 54-month period. Three hundred eighty CAS procedures were performed in 354 patients. Technical success was achieved in 372 cases (98%), and symptomatic lesions existed in 85 (24%) patients. No patient experienced periprocedural mortality or neuroprotective device-related complication. The 30-day stroke and death rate was 2.7%, and the overall complication rate was 6.9%. The overall major or fatal stroke rates in symptomatic and asymptomatic patients were 4.6% and 1.3%, respectively (not significant). The overall stroke and death rates between the symptomatic and asymptomatic groups were 5.8% and 2.4%, respectively (not significant). The median follow-up period was 29 months (range 1-53 months). With Kaplan-Meier analysis, the rates of freedom from 60% or greater ISR after CAS procedures at 12, 24, 36, and 48 months were 97%, 94%, 92%, and 90%, respectively. The rates of freedom from all fatal and nonfatal strokes at 12, 24, 36, and 48 months were 97%, 91%, 89%, and 85%, respectively. Multivariable analysis of significant univariate predictors identified that postendarterectomy stenosis (odds ratio [OR] 3.98, p = .02) and multiple stent placement (OR 3.68, p = .03) were independent predictors of ISR. Our study yielded favorable short-term and midterm clinical results using Carotid Wallstent with FilterWire neuroprotection. Late follow-up results showed low rates of fatal and nonfatal stroke and favorable ISR rates compared with other carotid stent trials. Postendarterectomy and multiple stent placement were associated with subsequent ISR.

Aged↗

PubMedDate not supplied

Chronically impaired endothelial vasoreactivity following oversized endovascular introducer sheath placement in porcine iliac arteries: implications for endovascular therapy.

The conventional endovascular aortic aneurysm procedure entails the placement of oversized introducer sheaths in relatively normal ileofemoral arteries to allow the delivery and deployment of endovascular prosthesis. Endoluminal manipulation with passage of oversized endoluminal devices can lead to endothelial denudation, resulting in impaired cellular function. The purpose of this study was to assess the time course of endothelial function with vasoreactivity following oversized endovascular sheath insertion ranging from 1 day to 16 weeks in normal porcine iliac arteries. Following oversized introducer sheath placement in bilateral iliac arteries, vasoreactivity was tested using both endothelium-dependent and -independent vasodilators. Intravascular ultrasonography showed a significant reduction in the luminal area at 12 and 16 weeks. This was similarly supported by morphometric analysis, which showed increased medial thickness with an elevated intima to media ratio at the same time course. Endothelium-dependent relaxation to bradykinin, calcium ionophore A23187, serotonin, and adenosine diphosphate all uniformly displayed attenuated endothelial dysfunction at all time points when compared with the control group. In contrast, endothelium-independent relaxation showed a decreased vasoresponsiveness at 4 weeks. In conclusion, this study underscored the detrimental and chronic endothelial dysfunction in a normal artery caused by oversized introducer sheath placement. Chronically impaired endothelial function may play a role leading to iliofemoral artery thrombosis or late occlusion, which were well-recognized adverse events following endovascular aneurysm procedures. Our study underscores the importance of appropriate patient selection to minimize potential sheath oversize and endograft device miniaturization to avoid vessel wall injury and maintain vasoreactivity.

Adenosine Diphosphate↗

PubMedDate not supplied

Metachronous double parathyroid adenomas involving two different cell types: chief cell and oxyphil cell.

OBJECTIVE: To describe a patient with the rare occurrence of metachronous double parathyroid adenomas involving two different cell types. METHODS: We present a case report and a summary of the related literature. RESULTS: Double parathyroid adenomas are rare, occurring in 1.7 to 9% of patients with primary hyperparathyroidism. Most double parathyroid adenomas are synchronous lesions; few metachronous double parathyroid adenomas have previously been reported. Most parathyroid adenomas are of the chief cell variety, with oxyphil cell adenomas occurring in less than 1% of cases. In a 73-year-old man with no prior history or known family history of endocrine disease, primary hyperparathyroidism developed, and cervical ultrasonography demonstrated a mass in the right side of the neck. Subsequent parathyroidectomy revealed a right superior chief cell adenoma. Postoperatively, the patient's parathyroid hormone and serum calcium levels returned to normal and remained so for at least 9 years. Twelve years after the first operation, recurrent hyperparathyroidism prompted repeated surgical exploration of the neck, which disclosed a large left superior parathyroid mass. Surgical excision and histologic examination revealed the lesion to be an oxyphil cell adenoma. CONCLUSION: To our knowledge, this is the first reported case of metachronous double parathyroid adenomas involving two different cell types: chief cell and oxyphil cell.

Adenoma↗