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Biomedical subjects

G Stansby

Publications and source records attributed to G Stansby.

103 records · Page 6Linked to original sources

Does vascular stapling improve compliance of vascular anastomoses?

Elastic properties of vessel walls are altered by vascular anastomoses. Such alterations may lead to neointimal hyperplasia, which is a common cause of reocclusion following vascular surgery. The severity of paraanastomotic hypercompliant zones and anastomotic compliance drop depend on suturing material and on elastic properties of the anastomotic vessel segments. This study compares paraanastomotic hypercompliance and anastomotic compliance drop when using a new vascular closure system (VCS) and a conventional, continuous suture line in the preparation of end-to-end anastomoses. Compliance of artery-artery, vein-artery, and polytetrafluoroethylene-artery anastomoses was measured in an artificial circulation system at mean pressures of 60, 90, and 120 mm Hg, comparing conventional suturing and the VCS. When using the VCS for vein-artery anastomoses, significantly less postanastomotic hypercompliance was achieved at mean pressures of 60 mm Hg (14.2 +/-3.8% above remote postanastomotic area), compared to suture (55.1 +/-14.8%, p<0.05). At 90 mm Hg, respective values were 11.0 +/-2.3% for VCS and 54.7 +/-10.1% for suture, p<0.01. At 120 mm Hg, in polytetrafluoroethylene-artery anastomoses, the anastomotic compliance drop was significantly less when using the continuous suture line (93.9 +/-1.1% below remote postanastomotic compliance), compared to VCS (97.2 +/-0.2%, p<0.05). Compared to conventional suturing, use of the VCS reduced postanastomotic hypercompliance in vein-artery anastomoses.

Anastomosis, Surgical↗

Echomorphologic and histopathologic characteristics of unstable carotid plaques.

BACKGROUND AND PURPOSE: Our hypothesis was that the carotid plaques associated with retinal and cerebrovascular symptomatology and asymptomatic presentation may be differ from each other. The aim of this study was to identify the sonographic and histopathologic characteristics of plaques that corresponded to these three clinical manifestations. METHODS: The echo process involved duplex preoperative imaging of 71 plaques (67 patients, 21 plaques were associated with retinal, 25 with cerebrovascular symptoms, and 25 were asymptomatic), which was performed in a longitudinal fashion. Appropriate frames were captured and digitized via S-video signal in a computer and digitized sonograms were normalized by two echo-anatomic reference points: the gray scale median (GSM) of the blood and that of the adventitia. The GSM of the plaques was evaluated to distinguish dark (low-GSM) from bright (high-GSM) plaques. Subsequent to endarterectomy, the plaques were sectioned transversely, and a slice at the level of the largest plaque area was examined for the relative size of necrotic core and presence of calcification and hemorrhage. RESULTS: Retinal symptomatology was associated with a hypoechoic plaque appearance (median GSM: 0), asymptomatic status with a hyperechoic plaque appearance (median GSM: 34), and cerebrovascular symptomatology with an intermediate plaque appearance (median GSM: 16) (P = .001). The histopathologic characteristics did not disclose differences between the three clinical groups. The hypoechoic plaque appearance was associated only with the presence of hemorrhage (median GSM for the hemorrhagic plaques, 6, and for the non-hemorrhagic ones, 20 [P = .04]). The relative necrotic core size and the presence of calcification did not show any echomorphologic predilection. CONCLUSION: Our results showed that distinct echomorphologic characteristics of plaques were associated with retinal and cerebrovascular symptomatology and asymptomatic status. Histopathologically, only the presence of hemorrhage proved to have an echomorphologic predilection.

Aged↗

Effect of naftidrofuryl and aspirin on platelet aggregation in peripheral vascular disease.

Platelet aggregation in whole blood (WB) was assessed in healthy subjects and in patients with peripheral vascular disease (PVD) using a WB-free platelet counting (WB-FPC) method. Aggregation induced by stirring and platelet agonists was significantly enhanced in PVD patients. WB-FPC aggregation induced by 5-HT was diminished significantly by incubation with naftidrofuryl (NAF) in WB of PVD patients. In contrast, aspirin (acetylsalicylic acid; ASA), added in vitro, did not significantly affect 5-HT or stirring-induced WB-PFC aggregation in PVD patients. Furthermore, 5-HT-induced WB-FPC was inhibited by NAF in blood collected from PVD patients that were taking low dose aspirin. These findings suggest that NAF may be of benefit to patients with hyperaggregable platelets and elevated plasma 5-HT concentrations, factors thought to predispose to thrombotic complications.

Adult↗

Atherosclerotic renal artery stenosis.

Atherosclerotic renal artery stenosis is a relatively common cause of hypertension and renal impairment in the elderly. We review its clinical features and the investigations and management options available.

Angioplasty, Balloon↗