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Biomedical subjects

V M Bernhard

Publications and source records attributed to V M Bernhard.

At least 19 recordsLinked to original sources
PubMed1992

Contrast-induced nephrotoxicity: the effects of vasodilator therapy.

The increasingly frequent use of contrast-enhanced imaging for diagnosis or intervention in patients with peripheral vascular disease has generated concern about the incidence and avoidance of contrast-induced nephrotoxicity (CIN). In this prospective study, we sought to identify those patients at greater risk of developing CIN and to evaluate the efficacy of vasodilator therapy with dopamine in limiting this complication. Baseline serum creatinine (Cr) concentrations were obtained on admission and daily for up to 72 hr after angiography in 222 patients undergoing 232 angiographic procedures. The preangiographic treatment was varied at 2-month intervals for 1 year. All patients received an intravenous infusion of 5% dextrose and 0.45% normal saline at a rate of 75 to 125 ml/hr. During the first interval patients received 12.5 g of 25% mannitol immediately prior to their contrast load, in addition to intravenous fluids. During the next 2-month period the patients were given renal dose dopamine intravenously (3 micrograms/kg/min) commencing the evening before angiography and continued to the next morning. During the latter half of the study the treatment regimens were modified so that the use of mannitol was restricted to patients with diabetes mellitus and dopamine to patients with serum creatinine concentrations of > or = 2 mg/dl. Postangiographic elevation in Cr occurred in 2, 10.4, and 62% of studies in patients with baseline creatinine levels of < or = 1.2 mg/dl, 1.3 to 1.9 mg/dl, and > or = 2.0 mg/dl, respectively. None of the patients receiving dopamine experienced an elevation in creatinine. There was no statistical correlation between age, diabetes, or medication with calcium channel blockers and CIN.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Improved sterile technique diminishes the incidence of positive line cultures in cardiovascular patients.

In order to determine the incidence of positive line cultures, especially as affected by differing protocols for line insertion, cultures were obtained from lines in residence for up to 4 days from cardiac patients (who received Cefuroxime) and vascular patients (who received Cefazolin) as prophylaxis perioperatively. Positive cultures were obtained from 95 (19%) of 496 lines in cardiac patients and 83 (31%) of 261 lines in vascular patients. There was a linear relationship between duration of line residence and the incidence of positive line cultures, increasing from 14% on Day 1 to 33% on Day 4. The use of full sterile technique at the time of insertion halved the incidence of subsequent positive line cultures. Four of the 403 (1%) patients each had a single episode of postoperative line sepsis. Another four patients developed wound infections with the same organisms as cultured from their lines. One patient has had a vascular graft infection with the same organism cultured as was isolated from a Swan-Ganz line 1 year previously. These data suggest that monitoring lines should be inserted using full sterile technique and removed as soon as the patient is hemodynamically stable.

Cardiac Surgical Procedures↗
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

Angioscopic assessment of fibrinolysis for impending in situ saphenous vein graft thrombosis.

A failing femorotibial in situ saphenous vein bypass graft was found by angioscopic examination to be lined with white thrombus and was successfully treated by intraoperative lytic therapy rather than by thrombectomy with a balloon catheter. The platelet-fibrin debris was completely cleared by 250,000 units of urokinase. There were no bleeding complications and the potential for mechanical damage to the venous endothelium was prevented. The in vivo angioscopic observations of fibrinolysis are described.

Aged↗
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↗
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

Carotid endarterectomy for chronic retinal ischemia.

Carotid arterial disease may result in a variety of ischemic ocular problems that can eventually lead to permanent blindness. From 1984 to 1988, 18 patients underwent reconstruction of the carotid artery in an attempt to restore normal retinal arterial flow and, thereby, reverse or prevent progression of ischemic oculopathy. During a mean period of 21 months after carotid arterial reconstruction, subjective improvement in vision as well as a resolution in eye and periorbital pain was reported in 87.5 per cent of the patients. Measured visual acuity improved or stabilized in 94.4 per cent; macular photostress recovery times improved in 87.5 per cent, funduscopic examinations noted improvement or resolution in ischemic signs in 93.3 per cent and intraocular pressures improved in two of three patients. One patient experienced recurrent episodes of amaurosis fugax, which resolved after two weeks and did not recur. A second patient experienced an increase in intraocular pressures with visual deterioration, required laser photocoagulation after which the condition of the patient stabilized but only after significant visual impairment. Carotid arterial reconstruction is effective for the treatment of ischemic oculopathy and is most beneficial if performed early, before the onset of irreversible neovascular glaucoma.

Aged↗
PubMed1979

Periorbital ultrasound findings. Hemodynamics in patients with cerebral vascular disease.

The direction of supraorbital and frontal artery flow and its response to compression of the superficial temporal, facial, and angular arteries were measured in 250 carotid arteries in 114 patients. All patients had arch and/or selective carotid arteriography. The carotid arteries were placed into the following three groups: hemodynamically normal, greater than 60% occlusion of the internal carotid artery, and total occlusion of the internal carotid artery. The test's accuracy was 94.5% in the hemodynamically normal group, 68.8% in the totally occluded group, and only 51.4% in the group with hemodynamically significant stenosis. Although the carotid Doppler examination is not reliable in detecting hemodynamically significant lesions of the internal carotid artery, it is valuable in assessing the adequacy of collateral cerebral circulation.

Carotid Artery Diseases↗
PubMed1979

White clot syndrome. Peripheral vascular complications of heparin therapy.

Heparin sodium-induced thrombosis is insidious and difficult to diagnose. If untreated, it results in death or major amputation. We have treated seven patients with thromboses resulting from platelet aggregation induced by heparin. Four patients had acute arterial ischemia of the lower extremity, venous gangrene developed in two, and one patient had an occluded autogenous vein femoral popliteal bypass in the immediate postoperative period. The platelet count was noticeably reduced in affected patients. White platelet thrombi were noted in four patients, three of whom had acute arterial occlusion. A white thrombus was the cause of immediate failure of a femoral popliteal graft. Electron microscopic examination of these thrombi demonstrated predominantly fibrin platelet aggregates with an occasional entrapped WBC and a rare RBC. All patients receiving heparin therapy must have platelet counts performed regularly. If thrombocytopenia is detected, platelet aggregation studies are indicated. When abnormal platelet aggregation is noted, heparin therapy should be reversed with protamine sulfate and the patient treated with low-molecular-weight dextran and warfarin sodium.

Aged↗
PubMed1978

Revascularization of the ischemic kidney.

Although acute renal artery obstruction causes cessation of kidney function, the viability of the nephron is often maintained by collateral circulation. When renal artery blood flow is restored, filtration is resumed and the resulting acute tubular necrosis is gradually resolved as renal tubular cells regenerate. We have observed several different mechanisms of acute renal artery obstruction resulting in anuric renal failure: temporary suprarenal placement of an aortic clamp during absominal aneurysmectomy, resulting in bilateral renal artery occlusion; embolus, presumably of cardiac origin, to a solitary kidney; and thrombosis of the distal aorta extending to a level proximal to the renal arteries. There is no correlation between the duration of renal artery occlusion and the viability of kidney parenchyma. Viability of the kidney can only be determined by visual inspection at operation and response to revascularization. When vascular obstruction is a possible cause of acute anuric renal failure, immediate angiography is indicated. If a correctable vascular lesion is identified, operative intervention is mandatory.

Acute Kidney Injury↗
PubMed1978

Comparison of caval filters in the management of venous thromboembolism.

Over a seven-year period, 38 Mobin-Uddin MU and 33 Kim-Ray Greenfield KG vena cava filters were inserted in 71 patients with no substantial complications or deaths directly related to the surgical procedure. Thirteen of the 16 early deaths were due to progression of associated diseases. The remaining three deaths were caused by pulmonary emboli and occurred in each instance after insertion of a MU filter. None of the 14 late deaths were related to the caval filter or sequellae of venous thrombosis. Inferior vena cava patency was objectively assessed in 36 patients by cavagram (22) or autopsy (14). Caval patency of 95% (18 of 19) in those with KG filters was significantly greater than the 47% patency (eight of 17) seen with MU devices (P less than .01). Gray scale ultrasound, when successful in visualizing the vena cava, was found to be a reliable indicator of patency. Venous stasis phenomena were noted in 50% of those with a patent cava and in 70% of those with an occlusion. Thus, it is not surprising that edema was found in only 38% of the patients as compared with 75% of the patients with the MU filter. Both of these devices are safe to insert. However, on the basis of superior patency rate, lower incidence of stasis phenomena, and the absence of recurrent pulmonary emboli in our series, we prefer insertion of a KG filter when caval interruption is required.

Adult↗
PubMed1978

Abdominal aortic aneurysm and retroperitoneal fibrosis. Ultrasonographic diagnosis and treatment.

Until changes of ureteric or vascular compromise are noted, retroperitoneal fibrosis usually goes unnoticed. When symptomatic retroperitoneal fibrosis has been associated with abdominal aortic aneurysm, ureteral involvement has uniformly been present. Three cases demonstrate a new ultrasonographic picture that can aid in early identification of retroperitoneal fibrosis before complications are manifest. In patients with abdominal aortic aneurysms, routine sonography may identify unsuspected retroperitoneal fibrosis, a factor that may be important in preoperative planning for safe surgical intervention.

Aorta, Abdominal↗