[A Cochrane report on carotid surgery: early endarterectomy in carotid stenosis is recommended].
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Biomedical subjects
Publications and source records attributed to D Bergqvist.
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Vascular surgery is in a dynamic phase of rapid development. Particularly endovascular procedures have revolutionized the care of vascular patients. Around 35-40% of all interventions in Sweden are endovascular. In all aspects of vascular surgery (arterial, venous, endovascular, biomaterials) there is a great need for more basic knowledge. The organization of vascular units must be centered around the vascular patient. Specialists need to collaborate in the care of each patient. It is proposed that the care of vascular patients should be organized in Vascular Departments.
The aim was to describe the phlebographic pattern of asymptomatic and symptomatic deep vein thrombosis (DVT) after total hip replacement by the use of a scoring system in 102 consecutive patients (54 asymptomatic, 48 symptomatic). The DVTs were scored from 1 to 3, and registered in a scoring system dividing the deep veins into 12 separate segments. The asymptomatic patients had a significantly lower total mean DVT score of 3.7 compared to 9.1 in the symptomatic group of patients. The mean ratio of the DVT scores in the deep muscle veins in conjunction with the superficial femoral vein in relation to the total mean score was significantly higher in the asymptomatic patients (74.9%) compared to the symptomatic group (62.4%). A direct sign of DVT, displayed as a filling defect, was seen on the phlebogram in 116 of the 119 legs, and concomitant nonfilling in other vein segments was noted in 6% of the asymptomatic patients, while in the symptomatic group this was the case to a significantly higher level, namely, 46%. A subgroup of asymptomatic patients operated unilaterally, with bilateral DVT had a significantly higher total mean DVT score on the operated side (4. 6) compared to the unoperated side (3.4). The total mean DVT score increased with time after surgery in the group of symptomatic patients. A low total mean DVT score with a predominance of DVT in, or in the connection to, the deep muscle veins is displayed among the asymptomatic patients. This is significantly different from the symptomatic patients who have more extensive DVTs, especially when diagnosed several weeks postoperatively, and frequently with edema and occlusive DVT.
BACKGROUND: Based on the current understanding that venous thrombosis starts perioperatively, administration of just-in-time low-molecular-weight heparin immediately before or in close proximity after hip arthroplasty may be more effective than usual clinical practice. METHODS: We performed a randomized, double-blind trial comparing subcutaneous dalteparin sodium given once daily immediately before or early after surgery with the use of postoperative warfarin sodium in 1472 patients undergoing elective hip arthroplasties. The primary end point was deep vein thrombosis detected using contrast venography performed after surgery (mean, 5. 7 days) in each group. RESULTS: The frequencies of deep vein thrombosis for patients with interpretable venograms receiving preoperative and postoperative dalteparin for all deep vein thrombosis were 36 (10.7%) of 337 (P<.001) and 44 (13.1%) of 336 (P<.001), respectively, vs 81 (24.0%) of 338 for warfarin; for proximal deep vein thrombosis, 3 (0.8%) of 354 (P =.04) and 3 (0.8%) of 358 (P =.03), respectively, vs 11 (3.0%) of 363. Relative risk reductions for the dalteparin groups ranged from 45% to 72%. Symptomatic thrombi were less frequent in the preoperative dalteparin group (5/337 patients [1.5%]) vs the warfarin group (15/338 patients [4.4%]) (P =.02). Serious bleeding was similar among groups. Increased major bleeding at the surgical site was observed for patients receiving preoperative dalteparin vs warfarin (P =.01). CONCLUSIONS: A modified dalteparin regimen in close proximity to surgery resulted in substantive risk reductions for all and proximal deep vein thrombosis, compared with warfarin therapy. Such findings have not been observed with low-molecular-weight heparin therapy commenced 12 hours preoperatively or 12 to 24 hours postoperatively vs oral anticoagulants. Increased major but not serious bleeding occurred in patients receiving preoperative dalteparin. Dalteparin therapy initiated postoperatively provided superior efficacy vs warfarin without significantly increased overt bleeding.
BACKGROUND: No randomized trials have directly evaluated the need for extended out-of-hospital thromboprophylaxis for patients who have hip arthroplasty in the United States or Canada. The uncertainty as to the need for extended prophylaxis in North American patients is complicated by early hospital discharge, resulting in a short thromboprophylaxis interval. METHODS: To resolve this uncertainty, we performed a randomized double-blind trial in 569 patients who underwent hip arthroplasty comparing the use of dalteparin sodium started immediately before surgery or early after surgery and extended out-of-hospital to an overall interval of 35 days with the use of warfarin sodium in-hospital and placebo out-of-hospital. RESULTS: For patients with interpretable venograms in the preoperative, postoperative, and combined dalteparin groups, new proximal vein thrombosis out-of-hospital was observed in 1.3%, 0. 7% (P =.04), and 1.0% (P =.02) of patients, respectively, compared with 4.8% in the in-hospital warfarin/out-of-hospital placebo group. The respective overall cumulative frequencies of all deep vein thrombosis were 30 (17.2%) of 174 patients (P<.001), 38 (22.2%) of 171 (P =.003), and 68 (19.7%) of 345 (P<.001) in the dalteparin groups compared with 69 (36.7%) of 188 for the in-hospital warfarin/out-of-hospital placebo group. For proximal deep vein thrombosis, the respective frequencies were 5 (3.1%) of 162 (P =.02), 3 (2.0%) of 151 (P =.007), and 8 (2.6%) of 313 (P =.002) compared with 14 (9.2%) of 153. No major bleeding occurred during the extended prophylaxis interval. CONCLUSIONS: Extended dalteparin prophylaxis resulted in significantly lower frequencies of deep vein thrombosis compared with in-hospital warfarin therapy. Despite in-hospital thromboprophylaxis, patients having hip arthroplasty in the United States and Canada remain at moderate risk out-of-hospital. The number needed to treat provides a public health focus; only 24 to 28 patients require extended prophylaxis to prevent 1 new out-of-hospital proximal vein thrombosis. Recent studies demonstrate that asymptomatic deep vein thrombi cause the postphlebitic syndrome; thus, extended out-of-hospital prophylaxis will lessen the burden to both the patient and society.
As carotid endarterectomy is a prophylactic procedure, it would seem particularly important to analyze complications with an aim to avoiding them. All carotid endarterectomies in Sweden are registered, and all serious complications (death and permanent neurological deficit) are analyzed in detail, classified and discussed within the profession. During the period 1994-1996 the frequency was 4.3 percent (technical causes in 17 percent, contraindications in 8 percent and dubious indications in 21 percent, but correct indication and surgery in 54 percent). Thus, even when conditions are optimal there is a certain price to pay for the prevention of ischemic stroke.
Carotid surgery prevents recurrent stroke in patients with symptomatic tight stenosis of the carotid artery. The Swedish Carotid Surgery Monitoring Registry seeks to promote selection of patients with significant spontaneous risk for recurrent stroke, with an eye toward expediting evaluation and minimizing surgical complications. To this end, professionals at participating hospitals are informed about their own patient selection and surgery risk in comparison with those in the country as a whole and with set targets. We report the results from the first two years, during which it is estimated that more than half of all patients eligible for carotid surgery in Sweden were included in the registry. Although almost all patients had recent onset of relevant neurological symptoms, less than 60% had a documented tight (80-99% occlusion) stenosis. While the final decision to operate a patient was made within 4 weeks of onset of symptoms for only 18% of the patients the first year, this proportion increased to 33% in the following year. The total incidence of surgery related stroke, myocardial infarct and death was 7.7%, while the incidence of severe stroke, myocardial infarct and death was 3.0%.
BACKGROUND: The aim of this study was to determine whether laparoscopic cholecystectomy (LC), in spite of its minimally invasive nature, causes coagulation activation. METHODS: Sixty-four patients undergoing LC were included prospectively. All received either dextran or low-molecular-weight heparin (LMWH). Blood samples taken the morning of the operation and the following morning were analyzed for TAT, FM, fragment 1+2, tPA, PAI-1, vWf, D-dimer, Hb, hematocrit, and APC resistance. RESULTS: Significant increases in TAT, FM, fragment 1+2, and D-dimer were seen, whereas APC resistance, Hb, and hematocrit decreased significantly. Dextran led to a decrease in vWf and no change in tPA, whereas LMWH led to an increase in both these parameters. CONCLUSIONS: Laparoscopic cholecystectomy causes coagulation activation. There are differences in the response between patients receiving dextran and LMWH as thromboembolism prophylaxis. Since most patients are discharged the day after the operation, there could be practical as well as theoretical advantages to using dextran.
PURPOSE: The purpose of this study was to evaluate the possibility of identifying alterations in blood supply to the spinal cord during thoracic aortic crossclamping. METHODS: In 17 pigs, a multiparameter PO(2), PCO(2,) and pH sensor was introduced into the intrathecal space for continuous monitoring of cerebrospinal fluid (CSF) oxygenation during aortic crossclamping. An epidural laser Doppler probe was used to measure spinal cord flux. After insertion of an aortic shunt from the left subclavian to the left iliac artery and interruption of the right subclavian and lumbar arteries (L2-L5), the thoracic aorta just distal to the left subclavian artery was clamped for 60 minutes. By placement of the distal aortic crossclamping below the level of L1 in group A (n = 9 animals), perfusion of only the abdominal visceral arteries was maintained. In group B (n = 8 animals), the distal aortic crossclamping was above the level of T12, and thus some spinal cord perfusion was maintained through the aortic shunt. RESULTS: The significant decrease in CSF PO(2) was observed within 3 minutes after the placement of the proximal aortic crossclamping and was normalized in all animals after establishment of the shunt flow. In group A, distal aortic crossclamping caused a decrease in CSF PO(2) with at least 50% of the preclamping values within 3 minutes. The mean CSF PO(2) of 2.99 +/- 0.70 kPa at 60 minutes of distal aortic crossclamping in group B was significantly higher than in group A (0.11 +/- 0.11 kPa; P <. 001). In group A, PCO(2) measurements showed no significant changes in 3 minutes after distal aortic crossclamping but revealed significantly higher values at 30 and 60 minutes compared with group B. Spinal cord flux values showed similar changes as CSF PO(2) during the whole experiment in both groups. CONCLUSION: In this experimental model of aortic crossclamping, continuous CSF oxygen tension monitoring allows rapid detection of alterations in spinal cord circulation.
BACKGROUND: The most important factors that determine the outcome after femoropopliteal and femorodistal arterial reconstruction are still controversial. This report analysis the factors that determine the early and late patency of distal arterial reconstruction. PATIENTS AND METHODS: A retrospective analysis of patency after femorodistal arterial reconstruction with a new method for evaluation of angiographic runoff was performed for 336 arterial reconstructions. The different pre-, per- and postoperative risk factors were analysed in a Cox proportional hazards model. RESULT: The patency was significantly better for vein grafts in comparison to composite grafts and prosthetic grafts. It was 74% for vein, 46% for composite and 43% for prosthetic reconstructions, respectively, at 12 months after arterial reconstruction. The cumulative life table patency rate in extremities with good, intermediate and poor runoff was 62, 30 and 10%, respectively at 36 months. The patency rates for extremities operated on for claudication was significantly better than for extremities operated on for critical ischaemia. The multivariate analysis of different factors in a Cox analysis revealed that only the status of distal runoff, the graft material and the site of the distal anastomosis independently and significantly influenced the patency rates. CONCLUSIONS: A new model for evaluation of distal runoff proved to predict the patency rate of femoropopliteal and femorodistal arterial reconstructions reasonably well in this retrospective analysis.
OBJECTIVES: to study the effects of hypervolaemic haemodilution with hypertonic saline-dextran solution (HSD) on regional blood flow and thrombogenicity of small diameter polytetrafluoroethylene (PTFE) grafts. DESIGN: blood flow in rabbit aorta, vena cava and femoral, renal and ear arteries was determined in five groups: controls, isovolaemic haemodilution with dextran-70 (10 ml/kg body weight (b.w. )), hypervolaemic haemodilution (10 ml/kg b.w.) with either dextran-70, 7.5% NaCl or a combination of dextran and NaCl (HSD). In a second series PTFE grafts were inserted into the vena cava of rabbits treated with hypervolaemic haemodilution with dextran, hypertonic saline or HSD and examined after two days. RESULTS: blood flow increased in aorta, vena cava and femoral artery after haemodilution. The increase was transient in animals treated with hypertonic NaCl alone but sustained in the dextran-70 groups. The grafts from animals treated with hypertonic saline alone had a lower thrombus mass and higher blood flow compared to those from rabbits haemodiluted with dextran-70 only, indicating that both dextran and NaCl have antithrombotic effects. Superior results were obtained with HSD solution. CONCLUSIONS: HSD solution has a strong flow-promoting action in several vascular beds and beneficial effects on the patency of small diameter vessel grafts.
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OBJECTIVES: to evaluate the effect of a modified aortic shunt on central haemodynamic variables during experimental thoracic aortic occlusion in a prolonged spinal cord ischaemia model. MATERIAL AND METHODS: central haemodynamic variables were evaluated during aortic cross-clamping. In the shunt group (n=11), after the placement of proximal and distal aortic clamps, distal aortic perfusion was restored through an aortoiliac shunt via the left subclavian artery. In the no-shunt group (n=11), spinal cord ischaemia was achieved with only proximal aortic cross-clamping. The clamping time was 60 minutes in the shunt group and 30 minutes in the no-shunt group. RESULTS: in the no-shunt group, all animals needed inotropic support, vasodilators and buffers during the experiment. None of these drugs were needed in the shunt group. In the no-shunt group, cross-clamping caused a significant increase in mean arterial pressure and heart rate compared to baseline values. These variables were stable in the shunt group during aortic occlusion. In the reperfusion period cardiac output, heart rate and arterial pCO(2)were significantly higher in the no-shunt than in the shunt group. CONCLUSION: the present experimental spinal cord ischaemia model, using double aortic cross-clamping with shunt, offers improved central haemodynamics. This enables the study of prolonged selective spinal cord ischaemia without interaction from vasoactive drugs or systemic reperfusion.
OBJECTIVE: to review published studies and assess the strength of the evidence for the use of antithrombotic agents for the prevention of re-occlusion after peripheral angioplasty. METHODS: a literature search was performed. All randomised comparative studies with patency assessments or clinical endpoints were included. The methods and results of the studies were compared and evaluated. RESULTS: eleven randomised trials were identified, six of them were double blind. The majority of patients included were those with femoropopliteal lesions. A significant benefit of aspirin in one placebo-controlled study is balanced by no apparent benefit in another study. No dose-dependent effect of aspirin in the range 50-1000 mg/day has been shown in any of the four studies investigating such an effect. None of the three studies comparing platelet inhibitors and oral anticoagulants have shown any differences in outcome and no other well-designed studies of anticoagulants have been reported. CONCLUSIONS: evidence for a reduction in the likelihood of re-occlusion or restenosis after peripheral transluminal angioplasty with platelet inhibitors remains equivocal. Evidence for the efficacy of any other agent in this indication is also lacking.
OBJECTIVES: To investigate spinal cord ultrastructure related to cerebrospinal fluid (CSF) oxygenation. DESIGN: experimental aortic occlusion model with intrathecal oxygen tension monitoring. MATERIALS AND METHODS: Two groups of pigs underwent proximal (P) or double (D) aortic occlusion for 30 min followed by 1 h of reperfusion. In a third group (I) segmental arteries distal to T3 were clamped for 90 min. A thin pO(2), pCO(2) and pH sensor was placed intrathecally for continuous monitoring of CSF. Spinal cord segments were studied by electron microscopy (EM). RESULTS: In group P, CSF-pO(2)rapidly decreased during clamping and major changes in pH and pCO(2)were seen. EM demonstrated neuronal degeneration with loss of cellular integrity and severe affection of organelles. In the group D, CSF oxygenation decreased to about half, but with only moderate changes in the metabolic parameters. Group I showed no significant changes in CSF measurements. The latter groups were similar at EM, showing only mild mitochondrial changes. CONCLUSIONS: The level of CSF oxygenation during aortic cross-clamping or segmental artery interruption seems to correlate with ultrastructural changes in the spinal cord. This online intrathecal monitoring technique may provide valuable information on spinal cord circulation during thoracoabdominal aortic surgery.
AIM: to determine whether Behçet's disease affects haemostatic function. SETTING: University Hospital, Turkey. PATIENTS: one hundred and twenty-seven consecutive patients with Behçet's disease, 34 of whom with a history of vascular involvement. METHODS: prothrombin fragment 1+2 tissue plasminogen activator, protein S and C, antithrombin, fibrinogen, von Willebrand factor, thrombomodulin and prothrombin time (PT) were measured in patient plasma. RESULTS: soluble thrombomodulin was significantly lower and von Willebrand factor (vWF) and tissue plasminogen activator (tPA) significantly higher in Behçet's patients. Patients with vascular involvement showed the highest levels of vWF and tPA. There was no activation of coagulation, not even in patients with an active disease at the time of sampling. CONCLUSION: there were indirect signs of endothelial activity or damage, particularly in patients with vascular involvement. Coagulation was not activated.
OBJECTIVES: to determine whether sigmoid-pHi diagnose colon ischaemia after aortoiliac surgery? DESIGN: single-centre, non-randomised, prospective study. PATIENTS AND METHODS: of 83 patients operated on between 1994 and 1998, 41 with risk factors for the development of colon ischaemia were monitored peri- and/or postoperatively with sigmoid-pHi. Peri-operative mortality was 26% (8/31) after operation for a ruptured abdominal aortic aneurysm (AAA), nil after operation for non-ruptured AAA. Thirty-five postoperative colonoscopies were performed. All non-survivors were examined post-mortem. RESULTS: of six patients developing colon ischaemia after emergency operations (five for ruptured AAA) all had pHi-values <7.1 for 16-80 h. In two patients with transmural gangrene, and who had pHi-values below 6.6, pHi-monitoring permitted early diagnosis, colectomy and recovery. Three patients with mucosal gangrene were treated conservatively and recovered. Nine patients without ischaemic lesions had pHi-values <7.1, during 1-5 h, without adverse outcome. Bilateral ligation of the internal iliac arteries increased the risk of colon ischaemia (p<0.0001). CONCLUSIONS: pHi-monitoring was diagnostic for colon ischaemia. Mucosal and transmural gangrene were distinguished. The importance of the internal iliac circulation was demonstrated. The low mortality rate, and the fact that no patient died from bowel ischaemia, suggests that sigmoid pHi-monitoring may improve survival after ruptured AAA.