Search PubMed⌕ Search

Biomedical subjects

G C Hunter

Publications and source records attributed to G C Hunter.

At least 73 records · Page 4Linked to original sources
PubMed1992

Peripheral vascular disease in heart transplant recipients.

The improved longevity of heart transplant recipients demands heightened awareness of the long-term complications of the procedure. Between 1979 and 1990, 232 patients received 241 heart transplants at our institution. Accelerated coronary atherosclerosis occurred in 45 (19%) of the 232 patients, typically appearing within 2 years of transplantation, whereas peripheral vascular disease (PVD) appeared in 23 (10%) of the 232 patients, usually within 3 years of transplantation. In the patients with PVD, 13 had occlusive disease, nine had aneurysms, and one patient suffered a vertebral artery dissection. Accelerated coronary atherosclerosis afflicted 12 (52%) of the 23 patients affected by PVD (p < 0.05) and preceded the development of PVD in all 12. Logistic regression analysis revealed risk factors predictive of the development of PVD after transplantation to be a pretransplant history of ischemic cardiomyopathy and posttransplant hypertension and hypertriglyceridemia (p < 0.05), with the presence of more than one risk factor increasing the probability of development of PVD. Those patients thus identified as at risk should be closely monitored for the development of PVD. Aggressive medical management of hypertension and hyperlipidemia in this subpopulation may forestall or prevent the development of peripheral vascular disease after heart transplantation.

Adult↗
PubMed1991

Iliac-enteric fistula following Dacron patch angioplasty.

We report a patient who developed fistulization between the jejunum and a Dacron patch placed at the bifurcation of the right common iliac artery during endarterectomy 14 years previously. The patient was successfully managed by resection of the iliac bifurcation and a segment of the involved bowel. While arterio-enteric fistulae typically involve prosthetic grafts, they may occur in association with artificial materials used to patch endarterectomy sites; hence, knowledge of technical detail is important in the diagnosis of this complication following endarterectomy.

Aged↗
PubMed1991

Effects of electrocautery on midline laparotomy wound infection.

This study compared the healing of midline fascial incisions made with either scalpel or electrocautery and inoculated with Escherichia coli in 57 Sprague-Dawley rats. At 7 days, tensile strength was significantly less when incisions were made with electrocautery than with a scalpel. Additionally, would strength was inversely related to the concentration of the inoculum of E coli. The use of electrocautery was also associated with more frequent bacteremia at 48 hours and higher mortality at 7 days. Our results suggest that the technique used to incise the abdominal fascia influences subsequent wound healing, particularly in contaminated wounds.

Animals↗
PubMed1991

Lipid peroxidation: a possible factor in late graft failure of coronary artery bypass grafts.

Atherosclerosis is the paramount cause of late vein graft failure after coronary artery bypass grafting. Lipid peroxidation, which may play a significant role in the initiation and progression of atherosclerosis, was examined in segments of vein grafts (n = 6) harvested at reoperation for coronary disease. These were analyzed for cholesterol, phospholipid, triglyceride, and lipid peroxides. Nonatherosclerotic vascular tissues, including coronary arteries (n = 6), saphenous veins (n = 9), and donor aortic specimens (n = 11) were analyzed for comparison. Risk factors for atherosclerosis including elevated serum cholesterol and triglycerides, smoking, and hypertension were more frequent in patients with coronary artery disease compared to organ donors. Lipid peroxides were elevated in explanted vein grafts when compared to either saphenous vein, coronary artery or donor aorta. Lipid peroxides were not significantly different in saphenous vein when compared to coronary artery, but levels in both of these tissues were greater than in donor aorta. Although increased levels of lipid peroxides in explanted veins may simply reflect morphologic changes in these grafts, the known effects of lipid peroxides on a number of biochemical events suggest that they may contribute directly to graft failure after coronary artery bypass grafting.

Adolescent↗
PubMed1991

Abdominal aortic aneurysm in the patient undergoing cardiac transplantation.

In the past 3 years at our institution 130 patients have undergone cardiac transplantation for ischemic cardiomyopathy in 49 (38%), idiopathic cardiomyopathy in 42 (32%), viral cardiomyopathy in 9 (6.9%), pulmonary hypertension in 8 (6%), and graft atherosclerosis in 2 (1.5%). Routine preoperative abdominal ultrasonography was performed on 98 (75%) of these patients with specific visualization of the abdominal aorta in 93 (95%). Abdominal aortic aneurysms (all infrarenal) were found before operation in four patients and only in the subgroup undergoing transplantation for ischemic heart disease (10.5%). They measured 3.4, 4.5, 3.6, and 3.8 cm before transplantation. Periodic evaluation by ultrasonography was carried out after transplantation during the 3-year period of this study. One aneurysm that was initially 3.6 cm increased to 4.0 cm and ruptured 2 months after transplantation. The patient died despite emergent surgery. Aneurysms in three patients who demonstrated rapid aneurysm expansion after transplantation were successfully repaired at 5, 20, and 33 months after transplantation when the lesions reached 5.5, 5.9, and 4.8 cm. A fifth patient with an initially normal (1.5 cm) aorta developed a symptomatic aneurysm of 4.1 cm, which was repaired uneventfully. The average expansion rate of these aneurysms after transplantation was 0.74 +/- 0.15 cm/year. This experience suggests that aneurysms are limited to patients undergoing transplantation for ischemic heart disease. Ultrasound examination may be appropriate for preoperative screening. Careful aortic surveillance after transplantation is important in patients having transplantation for ischemic cardiomyopathy because of the apparent rapid expansion rate compared to aneurysms in the population not receiving transplants.

Aorta, Abdominal↗
PubMed1991

Effects of hypertension on aortic antioxidant status in human abdominal aneurysmal and occlusive disease.

The biochemical mechanisms by which hypertension accelerates atherosclerosis and increases the risk of aortic aneurysm rupture are poorly understood. This study evaluates the effects of hypertension on aortic trace element concentrations and antioxidant status in tissue removed from 26 normotensive (NT) and 20 hypertensive (HT) patients. Twenty-seven of 46 patients (59%) had aneurysmal (AA), and 19 of 46 (41%) had occlusive disease (OD). Aortic iron concentrations were markedly higher in both OD and AA tissue compared with controls. A similar trend was observed with copper concentrations, with the highest elevations observed in HT AA tissues. No significant differences were observed in zinc concentrations, except that HT AA aorta had significantly lower zinc levels than either OD or control tissue. Aortic ascorbic acid concentrations in diseased aorta were lower than those of controls, but independent of blood pressure. Copper-zinc-superoxide dismutase activity was similarly reduced, with the lowest activity observed in diseased aorta from HT patients. Only HT AA aorta had significantly higher manganese-superoxide dismutase activity than controls. The aortas of patients with AA had significantly lower amounts of elastin and greater elastase activity than either controls or those with OD. However, the differences were independent of blood pressure. Hypertensive patients with OD and AA had 31% more and 27% less aortic collagen, respectively, than their NT counterparts (P less than 0.05). These data suggest that the reduction in aortic collagen and elastin in HT patients with AA compared with their NT counterparts may explain the larger size of aneurysms and predispose to their eventual rupture. Furthermore, the diminished antioxidant status associated with HT predisposes to lipid peroxidation, which contributes to the acceleration of these processes. Our studies were conducted in patients with established aortic aneurysmal and occlusive disease. Whether these observations are pertinent to the pathogenesis of AA and OD remains unclear and merits further study.

Antioxidants↗
PubMed1990

Chronic alcohol ingestion increases aortic lipid levels in rats.

We evaluated the effects of alcohol ingestion on aortic lipid concentrations in 15 pair-fed Sprague-Dawley rats divided into three groups of five animals each. Control rats were fed a liquid diet, with 36% of their energy provided by maltose-dextrin for 28 days, and the remaining two groups of rats were fed an equivalent proportion of their energy as alcohol for 28 days or 18 months. Alcohol-fed rats exhaled significantly greater quantities of ethane than did controls at 28 days and 18 months. Serum cholesterol levels increased by 40% and triglyceride levels increased by 80%, but phospholipid levels remained unchanged in alcohol-fed rats compared with controls. Aortic concentrations of cholesterol and phospholipids increased twofold and threefold, respectively, in alcohol-fed rats, with a corresponding alteration of the cholesterol-phospholipid ratio at both time intervals. Tissue triglyceride levels were only elevated at 28 days, and no differences in aortic lipid peroxide levels were detected between alcohol-fed rats and controls. The results of the study indicate that alcohol ingestion increases aortic cholesterol, phospholipid, and triglyceride levels at 28 days and cholesterol and phospholipid but not triglyceride levels at 18 months. The mechanisms underlying the accumulation of lipids in aortic tissue need further elucidation.

Alcoholism↗
PubMed1990

Evidence for lipid peroxidation in atherosclerosis.

Lipid peroxidation may play a significant role in the initiation and progression of atherosclerotic plaque. Freshly harvested normal and atherosclerotic human aortic tissue, coronary arteries and explanted vein grafts were snap frozen at -70 degrees C. Folch reagent (chloroform-methanol 2:1, v/v) was used to extract lipids from the homogenates. These extracts were assayed for cholesterol, phospholipid and triglyceride content. Lipid peroxide complexes in vessels were measured fluorometrically. Atherosclerotic plaque from patients with aortic aneurysmal and occlusive disease and coronary artery disease contained significantly greater amounts of cholesterol (15.54 +/- 9.71 vs 3.39 +/- 1.14 mg/g tissue) than controls (p less than 0.01). Lipid peroxide fluorochromes were similarly elevated in all atherosclerotic tissue (4.159 +/- 1.065 vs 3.087 +/- 0.497 fluoro units/g tissue) compared to control (p less than 0.01) with significant elevations in saphenous vein grafts and occlusive aortic disease. Although lipid peroxidation and lipid accumulation occur in close association in atherosclerotic plaque, the role of lipid peroxides in the pathogenesis of atherosclerosis remains to be determined.

Adolescent↗
PubMed1990

Effect of electrocautery on wound healing in midline laparotomy incisions.

The effect of electrocautery on midline fascial wound healing was studied in 108 Sprague-Dawley rats. Midline wound tensile strength was significantly reduced in fascia incised with the coagulation current compared with the cutting current or scalpel. In addition, tissue necrosis and inflammation as well as adhesion formation between the incision and abdominal viscera were more extensive in animals with incisions made using coagulation current. The results of the study indicate that the use of electrocautery coagulation current is associated with increased tissue damage and a significant reduction in the tensile strength of healing wounds. The contribution of electrocautery to wound complications in patients needs further evaluation.

Abdominal Muscles↗
PubMed1990

Gastric outlet obstruction caused by traumatic pseudoaneurysm of superior mesenteric artery.

Traumatic pseudoaneurysms of the superior mesenteric artery (SMA) are extremely rare. We describe two cases of posttraumatic proximal SMA pseudoaneurysms with symptoms of gastric outlet obstruction. Repair was accomplished by aorta-SMA bypass with saphenous vein. Injuries to the proximal SMA are easily missed at laparotomy, especially if intestinal ischemia or hematomas are absent. Recognition and repair are stressed to avoid the complications associated with pseudoaneurysm formation.

Adult↗
PubMed1990

Timing of carotid endarterectomy after acute stroke.

An arbitrary delay of at least 6 weeks before performing carotid endarterectomy after acute stroke has been recommended based on anecdotal reports. This prolonged interval may increase the danger of recurrent neurologic deficit before surgery. From September 1978 to September 1988, carotid endarterectomy was performed on 140 patients at variable intervals after stroke. Eleven patients had temporary stroke, which left 129 patients with neurologic symptoms that persisted for 3 weeks or had a cortical infarct on CT scanning. A prospective therapeutic protocol was applied to 82 patients admitted with acute stroke. They were observed until neurologic recovery reached a plateau, based on clinical observation by a neurologist, before performing angiography and carotid endarterectomy (group I). Forty-seven patients were not seen until after recovery from stroke was established (group II). At initial presentation, the severity of neurologic deficit was classified as mild, moderate, or severe in 31%, 58%, and 11%, respectively. Recovery before operation was registered as complete in 11%, mild residual in 66%, moderate residual in 21%, and severe residual in 2%. Group I patients (n = 82, 64%) were operated on within 6 weeks of stroke and group II (n = 47, 36%) were operated on at varying times after 6 weeks. No significant difference was found in the incidence of cerebrovascular events (1.2% vs 4.2%) and deaths (1.3% vs 2.1%) between groups I and II with respect to the timing of carotid endarterectomy, and no significant difference was found between patients operated on at 2, 4, 6, or more than 6 weeks after stroke.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

Value of radiographs and bone scans in determining the need for therapy in diabetic patients with foot ulcers.

Thirty-two diabetic patients with foot ulcers were evaluated. Twenty-five patients had foot radiographs, technetium-99m bone scans, and wound and bone cultures; the remaining seven patients had all the studies except bone scanning. Bone changes compatible with osteitis were present on 15 of 32 foot radiographs (47 percent) and on 16 of 25 bone scans (64 percent). Bacterial growth was present in 27 of 32 wounds (84 percent) and 23 of 32 bone cultures (72 percent). Twelve of 23 patients (52 percent) with positive bone cultures had evidence of bone destruction and periosteal reaction on radiographs. The remaining 11 of 23 patients (48 percent) without radiographic signs of osteitis had bacterial growth from their bone cultures. Bone scans were positive in 12 of 18 patients (67 percent) with positive bone cultures and negative in 6 of 18 positive bone cultures (33 percent). We conclude that neither foot radiographs, technetium-99m bone scans, nor wound cultures should be used as the sole criterion for determining the use of antibiotic therapy or amputation in diabetic patients with foot ulcers.

Adult↗
PubMed1989

Fibrinolytic treatment of residual thrombus after catheter embolectomy for severe lower limb ischemia.

Intraoperative intraarterial fibrinolytic therapy (IIFT) was employed in 28 patients with acute limb ischemia. In 17 patients, significant residual calf thrombus was demonstrated by completion arteriography after standard balloon catheter thromboembolectomy, whereas in 11, pretreatment arteriography was not obtained. With the patient systemically heparinized, a bolus of fibrinolytic agent was instilled into the distal vessels below an inflow occlusion clamp. Among the 17 patients under angiographic control, arteriography was repeated after 30 minutes and a second bolus was injected if significant residual thrombus was still present. Successful lysis was achieved in 88% of these 17 limbs and streptokinase (SK) and urokinase (UK) were equally effective. The dosage of SK varied between 50,000 and 150,000 units (seven patients) and of UK between 35,000 and 150,000 units (21 patients). Serum fibrinogen levels declined significantly after IIFT (t test; p less than 0.05), but the average level remained within the normal range. Major bleeding developed in two patients, both of whom received SK and underwent a concomitant major abdominal vascular procedure, with a severe fall in fibrinogen values to 10 and 17 mg/dl. A minor groin hematoma occurred in one patient treated with UK. There was a significant difference in the incidence of bleeding between SK (2/7) and UK (1/21) (chi 2; p less than 0.05). Compartment syndrome developed in six limbs (21%). Amputation was required in two patients (7%). There was no correlation between prolongation of ischemia time as a result of IIFT and the incidence of compartment syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheterization↗
PubMed1989

Subclavian artery-to-innominate vein fistula: a case caused by subclavian venous catheterization.

Arteriovenous fistulas caused by subclavian vein catheterization occur rarely. Most subclavian vein catheters are inserted through an infraclavicular subclavian venipuncture with passage of a vessel dilator and peel-away sheath over a guidewire. We report a previously undescribed complication of this technique, namely, a right subclavian artery-to-right innominate vein fistula. The mechanism of injury was perforation through the opposing walls of the respective vein and artery due to stiffness of the vessel dilator that could not negotiate the curve from the subclavian vein to the innominate vein. Measures to avoid this complication are described.

Arteriovenous Fistula↗
PubMed1989

Aortic blebs: possible site of aneurysm rupture.

Although the growth and rupture of abdominal aortic aneurysms are commonly explained by Laplace's law, the final events that precede aneurysm rupture are not fully understood. Local excrescences within the wall of abdominal aortic aneurysms were observed in four of five patients studied with preoperative CT scanning, and were removed from six patients at the time of surgery. These protrusions were filled with thrombus, and on histologic examination marked attenuation of the aortic wall, focal loss of elastic fibers, and inflammatory cell infiltrates of lymphocytes, plasma cells, and occasional multinucleate giant cells were seen. The presence of these blebs and their microscopic characteristics suggest their potential as a mechanism for rupture and recognition of this deformity by use of abdominal CT scanning may indicate the necessity for prompt surgical intervention. Further careful clinicopathologic correlation is required to clearly establish these localized defects in the aneurysm wall as a cause for rupture.

Aged↗