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Biomedical subjects

D Bergqvist

Publications and source records attributed to D Bergqvist.

At least 145 records · Page 8Linked to original sources
PubMed1997

I. Impaired dark adaptation in symptomatic carotid artery disease.

It has been known for more than a century that even slight hypoxemia reduces dark adaptation. We studied dark adaptation in symptomatic carotid artery disease. Twenty-one consecutive patients scheduled for first-time carotid endarterectomy and 31 age-matched control subjects with normal carotid arteries were examined by dark adaptometry monocularly and were tested repeatedly on consecutive days. The average degree of internal carotid stenosis on the symptomatic side was much greater than that on the contralateral side. Dark adaptation was markedly impaired in the patients as compared with the control subjects. In the patients there was no difference in dark adaptation between the symptomatic and nonsymptomatic sides. The existence of carotid stenosis correlated to the level of dark adaptation. Pupillary size and age correlated to the dark adaptational level but did not affect the effect of carotid stenosis on dark adaptation. The decreased dark adaptation may be due to insufficient blood supply or repeated subclinical microembolization to the retinae, the brain, or both.

Aged↗
PubMed1997

II. Improved dark adaptation after carotid endarterectomy. Evidence of a long-term ischemic penumbra?

We have reported that dark vision is impaired in symptomatic carotid artery disease and that the impairment correlates with internal carotid artery stenosis. To find out whether this impairment is reversible after carotid endarterectomy, dark adaptation was examined pre- and postoperatively. Twenty-one consecutive patients were examined by dark adaptometry. Two examinations were done for each eye on two consecutive days pre- and postoperatively. Thirty-one matched control subjects were examined under identical conditions. The control subjects did not have clinical evidence of carotid artery disease. Patients and control subjects were free of ophthalmologic disorders. Dark vision frequently improved remarkably after endarterectomy. The average retinal sensitivity to light in darkness on the operated side doubled, and there was also improvement on the nonoperated side. There was no significant change in dark vision in the control subjects, negating a learning effect. The findings suggest the existence of reversible neuronal ischemia secondary to hemodynamic causes or frequent subclinical microembolization. Because the circulatory conditions are optimized, formerly inactive, surviving neurons may regain function.

Aged↗
PubMed1997

The post-discharge prophylactic management of the orthopedic patient with low-molecular-weight heparin: enoxaparin.

This prospective, double-blind trial was performed to determine whether 4 weeks' prophylaxis with enoxaparin after total hip replacement (THR) is more effective in protecting against deep vein thrombosis (DVT) than prophylaxis during hospitalization. Two hundred sixty-two patients undergoing THR were given enoxaparin 40 mg once daily during hospitalization (9 +/- 2 days) before being randomized at discharge to continue enoxaparin (N = 131) or receive placebo (N = 131) for a total of 1 month (30 +/- 4 days). According to intention-to-treat analysis, 43 DVT and 2 pulmonary emboli (PE) occurred in the placebo group (34.4%) versus 21 DVT and no PE in the enoxaparin group (P < 0.001). The reduction in proximal DVT was also significant (21.4 vs 6.1%; P < 0.001). No major bleeding complications developed. Prophylaxis with enoxaparin for one month significantly reduces venous thromboembolic disease in patients undergoing THR compared to conventional prophylaxis during hospitalization.

Adult↗
PubMed1997

Influence of twist on vein and PTFE graft hemodynamics: an ex vivo experimental study.

OBJECTIVE: In an ex vivo infusion model, the effect of different factors affecting the critical level of twist in vein and PTFE grafts was analysed. SETTING: University Hospital, Department of Surgery. EXPERIMENTAL DESIGN: Saline perfusion of grafts with various diameter and length under constant high (90 ml/min) and low (50 ml/min) flow rates against various peripheral resistance was performed. MEASURES: The pressure changes in the grafts were measured at increasing increments of twisting. RESULTS: The critical level of twist appears to be dependent on the diameter, length, stretching, status of peripheral resistance, amount of volume flow and the type of graft material, varying between 90 to more than 360 degrees. In vein grafts critical twisting appeared earlier with a decrease in diameter, shortening in length, high peripheral resistance, high flow rate and stretching. PTFE grafts especially with external spiral support were resistant to twist. CONCLUSIONS: These data suggest that the critical level of graft twist is dependent upon multiple factors and moderate or even high grade twist with especially externally supported PTFE grafts regardless of length and long mobilized vein grafts do not lead to hemodynamic changes. On the other hand total cessation of flow occurs at lower degrees of twist in stretched, short vein grafts.

Blood Vessel Prosthesis↗
PubMed1997

Incidence of thromboembolic complications after laparoscopic cholecystectomy: review of the literature.

The purpose of this study was to quantify the risk of thromboembolic complications after laparoscopic cholecystectomy by a survey of the literature. We reviewed 60 laparoscopic cholecystectomy series consisting of 153,832 patients. The average mortality was 0.08%. The average rate of fatal pulmonary embolism was 0.02% and total pulmonary embolism 0.06%. The average rate of reported deep vein thrombosis was 0.03%. We conclude that laparoscopic cholecystectomy is a safe procedure, and the rate of clinically evident postoperative thromboembolic complications is probably lower than after conventional cholecystectomy. A lingering bias due to the overrepresentation of young and healthy patients early in the era of laparoscopic cholecystectomy could, however, still affect these figures. An underreporting of the lesser complications is likely. The risk is not negligible, though, and some authors have recommended thromboembolism prophylaxis, although further studies are necessary to find the optimal prophylaxis strategy. The true incidence is possible to establish only by using objective diagnostic methods for surveillance.

Cholecystectomy, Laparoscopic↗
PubMed1997

Female gender and resistance to activated protein C (FV:Q506) as potential risk factors for thrombosis after elective hip arthroplasty.

Resistance to activated protein C (APC) caused by the R506Q mutation in factor V is the most common inherited risk factor for venous thrombosis. To elucidate whether APC-resistance is a risk factor for venous thrombosis after elective total hip replacement, the association between APC-resistance (presence of FV:Q506 allele) and postoperative thrombosis was investigated in patients (n = 198) randomised to received short (during hospitalisation, n = 100) or prolonged prophylaxis (three weeks after hospitalisation, n = 98) with low molecular weight heparin (LMWH). Among APC-resistant individuals receiving short prophylaxis, 7/10 developed thrombosis as compared to 2/12 receiving long prophylaxis (p <0.0179). Odds ratio for association between APC-resistance and thrombosis in the short prophylaxis group was 4.2 (CI 95% 1.02-17.5) (p <0.0465). Among those receiving prolonged prophylaxis, there was no increased incidence of thrombosis associated with APC-resistance. Two unexpected observations were made. One was that APC-resistance was much more common in women (19/109) than in men (3/89) (p <0.001). The other was that even women without APC-resistance were much more thrombosis-prone than men. Thus, 24/48 of women with normal FV genotype and short prophylaxis developed thrombosis vs 8/42 among men, p = 0.002. The increased risk of thrombosis associated with female gender and APC-resistance was neutralised by the prolonged treatment. In conclusion, among patients receiving short prophylaxis, female gender was found to be a strong risk factor for venous thrombosis. Even though APC-resistance appeared to be a risk factor for postoperative thrombosis, the uneven distribution of APC-resistance between men and women, taken together with the increased risk of thrombosis among women, precluded valid conclusions to be drawn about the association between APC-resistance and an increased risk of thrombosis. Our results suggest that prolonged prophylaxis with LMWH after hip surgery is more important for women than for men.

Adult↗
PubMed1997

An experimental porcine model of partial ischaemia of the distal colon.

OBJECTIVE: Ischaemia of the colon is a major challenge in aortoiliac surgery. The aim was to establish an animal model of partial distal colonic ischaemia to study interventional strategies. DESIGN: Randomised experiment. SETTING: University Hospital. Department of Experimental Research. MATERIAL: 19 pigs. INTERVENTIONS: 11 Pigs were subjected to ischaemia consisting of total occlusion of the inferior mesenteric artery and partial occlusion of the superior mesenteric artery. Eight animals were sham controls. Dextran was given. MAIN OUTCOME MEASURES: Haemodynamic measurements, intramucosal pH-measurements (pHi) and histological grading. RESULTS: Both ischaemic animals and controls remained haemodynamically stable. It was possible to maintain stable ischaemia in the distal colon in the pHi-range of 6.9-7.1. There was histological mucosal damage of the distal colon in ischaemic animals but not in controls. CONCLUSIONS: The model could be of value when studying interventional strategies to reduce or reverse ischaemia.

Animals↗
PubMed1996

Low-molecular-weight heparin (enoxaparin) as prophylaxis against venous thromboembolism after total hip replacement.

BACKGROUND: The risk of venous thromboembolism in patients undergoing total hip replacement is known to be high. However, the optimal duration of prophylaxis with anticoagulant agents after this procedure is unknown. We sought to determine whether one month of anticoagulant therapy with the low-molecular-weight heparin enoxaparin is more effective than enoxaparin therapy given only during the hospitalization for surgery. METHODS: Two hundred sixty-two patients undergoing total hip replacement received enoxaparin during their hospitalizations (average stay, 10 to 11 days). They were then randomly assigned to receive enoxaparin or placebo (131 patients each). Blinded outpatient therapy (or placebo) was continued long enough that the total treatment period, inpatient plus outpatient, was one month for each patient. Bilateral ascending phlebography was performed 19 to 23 days after discharge, with deep-vein thrombosis as the primary end point. Distal and proximal thrombosis, pulmonary embolism, and hemorrhage were also recorded, as were deaths. RESULTS: Venography was adequate in 116 patients in the placebo group and 117 in the enoxaparin group. We observed 43 episodes of deep-vein thrombosis and 2 episodes of pulmonary embolism in the placebo group, but only 21 episodes of deep-vein thrombosis and no episodes of pulmonary embolism in the enoxaparin group (incidence of thromboembolism, 39 percent and 18 percent, respectively; P<0.001). The difference in the incidence of proximal deep-vein thrombosis was also significant (24 percent and 7 percent in the placebo and enoxaparin groups, respectively; P<0.001). Six enoxaparin groups, respectively; P<0.001). Six patients in the enoxaparin group and one patient in the placebo group had hematomas at their injection sites. No patients died or had major complications. CONCLUSIONS: There were significantly fewer venous thromboembolic complications in patients undergoing elective hip replacement when prophylaxis with enoxaparin was given for a total of one month, rather than only during the hospitalization.

Adult↗
PubMed1996

Experimental haemorrhage and blood component transfusion in humans: no change in plasma concentration of thrombin-antithrombin complex and plasmin-antiplasmin complex.

The influence of haemorrhage and blood transfusion on primary haemostasis, coagulation and fibrinolysis was investigated in ten healthy male volunteers. Acute loss of 10% of the blood volume did not give any significant alteration in thrombin- antithrombin III (TAT) complex and plasmin-alpha 2-antiplasmin (PAP) complex levels compared with a control series. The skin bleeding time with the Simplate II device was not altered after the 10% blood loss. Acute loss of 10% of blood volume followed by transfusion of packed red cells or stored plasma did not resulted in any significant change in bleeding time, TAT and PAP complex levels. It could be concluded that a controlled haemorrhage does not give any detectable changes of the platelet dependent primary haemostasis, blood coagulation and fibrinolysis. Transfusion of one unit of packed red cells or stored plasma does not seem to adversely affect the haemostasis.

Adult↗
PubMed1996

Thoracic and thoracoabdominal aortic aneurysm and dissection: an investigation based on autopsy.

The city of Malmö (population approximately 230,000) has a fairly stable urban population and a high autopsy rate (83 per cent of all deaths). Autopsy records for the period from 1958 to 1985 were scrutinized and three groups of patients were defined: those with asymptomatic thoracic aortic aneurysm (TAA), those with rupture of the thoracic aorta, and those with dissection. The findings were used to calculate prevalence and incidence according to age and sex. Asymptomatic TAA was found in 205 patients (109 men). There was a predominance of men in higher age groups and about 5 per cent of the lesions were thoracoabdominal. Rupture of the thoracic aorta was the cause of death in 63 patients; no age difference between the sexes was observed. Death as a result of dissection occurred in 216 patients, women dying on average 7 years later than men. The incidence of rupture was 0.9 per 100,000 for men and 1.0 per 100,000 for women; the incidence of dissection was 3.2 per 100,000 for both sexes. Prevalence and incidence of fatal complications of TAA are low; this may influence decisions about where these patients should be treated.

Adolescent↗
PubMed1996

Comparison of the cost of preventing postoperative deep vein thrombosis with either unfractionated or low molecular weight heparin.

The relative costs were analysed of (1) no prophylaxis against deep vein thrombosis (DVT), (2) selective treatment of DVT after confirmation of diagnosis, (3) general prophylaxis with standard low-dose unfractionated heparin and (4) general prophylaxis with low molecular weight heparin (LMWH) in patients undergoing elective general abdominal surgery or elective hip surgery. The mean calculated costs per patient undergoing general abdominal surgery were: Swedish crowns (SEK) 1950 for no prophylaxis, SEK 5710 for selective treatment of DVT, SEK 735 for prophylaxis with unfractionated heparin and SEK 665 for prophylaxis with LMWH. The corresponding costs for hip surgery were SEK 3930, SEK 10790, SEK 1730 and SEK 1390 respectively. Thus, the least expensive management strategy in patients undergoing elective general abdominal or hip surgery would appear to be general prophylaxis with either unfractionated heparin or LMWH. Furthermore, general prophylaxis with LMWH would appear to be more cost-effective than general prophylaxis with unfractionated heparin.

Blood Loss, Surgical↗
PubMed1996

Early attachment of platelets, leukocytes, and fibrinogen in endothelial cell seeded Dacron grafts.

Endothelial cell seeding has been advocated as a method for reducing the thrombogenicity of prosthetic grafts. Principally two different techniques for endothelial cell seeding can be used: immediate seeding of grafts followed by implantation or initial growth and establishment of an endothelial cell-covered surface before subsequent late implantation. This study was designed to determine whether the immediate seeding technique altered thrombogenicity directly after graft implantation. Carotid arteries from 19 sheep were replaced with Dacron interposition grafts; one side was seeded with endothelial cells and the other side was left unseeded. The dynamics of thrombus formation involving radiolabeled platelets, leukocytes, and fibrinogen were studied for 4 hours with flow reduced to 35 ml/min. No difference in platelet uptake (approximately 6-fold increase compared to baseline values) was found between endothelial cell seeded and unseeded grafts. Likewise, there were no differences in leukocyte uptake (approximately 4-fold increase) or fibrinogen uptake (approximately 10- to 15-fold increase) between the two groups. No differences were demonstrated with regard to patency or thrombus weight. In this experimental investigation we were unable to verify any change in the uptake of platelets, white blood cells, or fibrinogen between endothelial cell seeded and unseeded Dacron grafts during the first 4 hours after graft placement. Immediate seeding does not affect the initial thrombogenicity of grafts.

Animals↗
PubMed1996

Amputation risk and survival after embolectomy for acute arterial ischaemia. Time trends in a defined Swedish population.

OBJECTIVES: To assess the outcome of embolectomy over an 19 year period. METHODS: Time trends in the outcome of acute arterial thrombo-embolectomy of the extremities were analysed in a population-based cohort of 1190 patients operated on between 1965-83. RESULTS: A total of 262 (22%) initial amputations were performed. The limb salvage rates at 5 years postoperatively were lower between 1975-79 (61%) than between 1965-69 (81%). A proportional hazards model revealed a relative hazard (RH) of amputation of 2.2 (95% confidence interval (CI) 1.3-3.3) for 1975-79 compared with 1965-69. Operation at any district hospital entailed a 70% higher risk of amputation (RH 1.7; 95% CI 1.3-2.5) compared with the University hospital. The relative survival rate at 5 years postoperatively decreased towards the end of the study period (33% between 1975-79 compared with 43% between 1965-69). Younger age-groups had a considerably lower risk of death in the University hospital compared with the county and district hospitals. CONCLUSIONS: Contrary to the results in other hospital based reports no improvement in amputation or survival rates since 1965 could be demonstrated in this large series with no patient selection.

Acute Disease↗