Biomedical subjects

V M Bernhard

Publications and source records attributed to V M Bernhard.

At least 37 records · Page 2Linked to original sources

PubMed1993

Risk factors for stroke in patients undergoing coronary artery bypass grafting.

Stroke is a significant cause of morbidity and mortality following coronary artery bypass grafting (CABG). Over a 30-month period, 245 consecutive patients undergoing elective CABG were prospectively examined to determine which risk factors might predispose to stroke following surgery. The risk factors evaluated included hypertension, diabetes, hypercholesterolemia, hypertriglyceridemia, smoking, atrial fibrillation, a history of cerebrovascular accident or transient ischemic attack, carotid artery stenosis > 60% documented by duplex scanning, severe atherosclerosis of the ascending aorta, and the presence of ventricular thrombus. Postoperative stroke occurred in five of the 245 patients (2%), four evident immediately on awakening and one on day 7 after surgery. The probable causes of the immediate strokes were atheroembolism in three patients and severe ipsilateral carotid stenosis in one. Hypertensive hemorrhage was responsible for the one case of delayed stroke. In this study, carotid artery stenosis did not presage stroke following CABG, but ventricular thrombus was highly predictive of stroke after surgery.

Aged↗

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

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

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↗

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

Prevention of amputation by diabetic education.

This prospective randomized study evaluated the influence of a simple education program on the incidence of lower extremity amputation in diabetic patients. Two hundred three patients were randomized into two groups: Group 1, education (103 patients, 203 limbs) and Group 2, no education (100 patients, 193 limbs). There were no significant differences in medical management or clinical risk factors between the two groups. The amputation rate was three times higher in Group 2 (21 of 177 limbs versus 7 of 177 limbs; p less than or equal to 0.025), the ulceration rate was three times higher in Group 2 (26 of 177 limbs versus 8 of 177 limbs; p less than or equal to 0.005), and there was no difference in the overall incidence of infection (2 of 177 limbs). Overall success in Group 1 was highly significantly different from Group 2 (160 of 177 limbs versus 128 of 177 limbs; p less than or equal to 0.0005). This study demonstrated that a simple education program significantly reduced the incidence of ulcer or foot and limb amputation in diabetic patients.

Amputation, Surgical↗

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

Efficacy of prophylactic antibiotics in vascular surgery: an arterial wall microbiologic and pharmacokinetic perspective.

This prospective study examined microbiologic features of arterial tissue and pharmacokinetics and bioactivity of cefamandole and cefazolin in patients undergoing elective primary prosthetic aortoiliofemoral/infrainguinal reconstruction. Double-blind, randomized, perioperative prophylaxis (1 gm intravenously every 6 hours for nine doses) with cefamandole or cefazolin was administered to 47 patients. Specimens of blood serum, subcutaneous fat, thrombus, atheroma, and arterial wall were obtained for culture and minimal inhibitory concentration and drug level analysis by high-pressure liquid chromatography. The serum half-life (hr +/- SEM) was 1.43 +/- 0.36 for cefamandole and 2.22 +/- 0.40 for cefazolin. Over the first 2 hours of surgery and for all time intervals combined, the serum concentration of cefazolin was significantly higher (p less than 0.025) than cefamandole. Irrespective of sampling time, the tissue concentration of cefazolin was significantly greater (p less than 0.005) than cefamandole. Positive arterial tissue cultures were obtained in 12 of 29 patients (41.4%) from 23 of 116 (19.8%) arterial tissue specimens. Coagulase-negative Staphylococcus was the predominant isolate, 64 of 93 (68.8%). Twenty-five of the 51 coagulase-negative staphylocci tested (49%) were slime-producers. During surgery, the arterial tissue concentration of cefamandole fell below the geometric mean minimal inhibitory concentration against all organisms combined, and against S. aureus (with the highest minimal inhibitory concentration of the prevalent isolates), significantly more often than the concentration of cefazolin. The data show that a significant number of primary elective aortoiliofemoral/infrainguinal reconstructions are associated with positive arterial tissue cultures, which represent a potential source of graft infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteries↗

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↗