Antithrombotic drug therapy after infrainguinal vascular surgery.
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Administration, Oral↗
Biomedical subjects
B Lindblad
Publications and source records attributed to B Lindblad.
Endovascular repair of descending thoracic aortic aneurysms: an early experience with intermediate-term follow-up.
PURPOSE: The purpose of this study was to report an initial experience with the endovascular repair of descending thoracic aortic aneurysm. Complications and intermediate-term morphologic changes were identified with the intent of altering patient selection and device design. METHODS: Endografts were placed into 25 patients at high-risk for conventional surgical repair over a 3(1/2)-year period. Devices were customized on the basis of preoperative imaging information. Follow-up computed tomography scans were obtained at 1, 3, 6, and 12 months and yearly thereafter. Additional interventions occurred in the setting of endoleaks, migration, and aneurysm growth. RESULTS: The overall 30-day mortality rate was 20% (12.5% for elective cases; 33% for emergent cases). There were 3 conversions to open repair. Neurologic deficits developed in 3 patients; 1 insult resulted in permanent paraplegia. Neurologic deficits were associated with longer endografts (P =.019). Three endoleaks required treatment, and 1 fatal rupture of the thoracic aneurysm treated occurred 6 months after the initial repair. Migrations were detected in 4 patients. The maximal aneurysm size decreased yearly by 9.15% (P =.01) or by 13.5% (P =.0005) if patients with endoleaks (n = 3 patients) were excluded. Both the proximal and distal neck dilated slightly over the course of follow-up (P =.019 and P =.001, respectively). The length of the proximal neck was a significant predictor of the risk for endoleakage (P =.02). CONCLUSION: The treatment of descending thoracic aortic aneurysms with an endovascular approach is feasible and may, in some patients, offer the best means of therapy. Early complications were primarily related to device design and patient selection. All aneurysms without endoleaks decreased in size after treatment. Late complications were associated with changing aneurysm morphologic features and device migration. The morphologic changes remain somewhat unpredictable; however, alterations in device design may result in improved fixation and more durable aneurysm exclusion.
Aged↗
Endovascular healing is inadequate for fixation of Dacron stent-grafts in human aortoiliac vessels.
BACKGROUND: migration and kinking of stent-grafts can occur late after endovascular aneurysm repair. It is unknown if endovascular grafts incorporate enough to be permanently anchored. In this report, healing of aortic stent-grafts was assessed in humans. PATIENTS AND METHODS: we retrieved 23 Dacron stent-grafts from patients treated for an aortic aneurysm since 1993. Twelve stent-grafts were explanted at late conversion to open repair and 11 at autopsy. The deaths were unrelated to graft fixation. The median age of the patients was 74 years (IQR 55-84 years) and the grafts were explanted 9 months (1-31 months) after insertion. Microscopic slides were prepared by conventional techniques or by cutting and grinding arterial specimens embedded in plastic with the stent-grafts in situ. RESULTS: the stent-grafts detached readily from the native arteries at surgery or autopsy, except when the stents had hooks or barbs which engaged the vessel wall. A space filled with poorly organised blood components persisted between the graft and the aortic wall 2.5 years after implantation. No firm incorporation of the grafts was observed proximally in the aneurysm neck or distally in the iliac segment. A friable neo-intimal layer covered parts of the luminal aspect of the grafts. CONCLUSIONS: endovascular healing provides poor fixation of Dacron stent-grafts in humans. At present, fixation relies on the mechanical properties of the stent-grafts.
Aged↗
The impact of stent design on proximal stent-graft fixation in the abdominal aorta: an experimental study.
OBJECTIVE: to study the proximal fixation of different aortic stent grafts in comparison to a hand-sewn anastomosis. DESIGN: experimental study. MATERIAL: the infrarenal aorta of 16 human cadavers were exposed, left in situ and transected 3 cm above the aortic bifurcation to mimic an infrarenal aortic neck. Stent grafts were deployed through a sheath 5 cm into the aorta. Ancure, Talent, Vanguard, Zenith and a Palmaz based stent graft were assessed. In addition a polyester graft was anastomosed to the aorta by running sutures. Distal force was applied to the grafts in increments of 0.5 Newton until the stent grafts were completely dislodged from the aorta. The displacement force (DF) was thereby determined. RESULTS: a force of 150 N (140-160) applied to the hand-sewn graft resulted in tearing of the aorta, without breakage of the sutures. The median displacement force was for Talent 4.5 N (1.3-5.5), Vanguard 9.0 N (3. 5-12), Ancure 12.5 N (12-14), Zenith 24 N (23-26.5) and Palmaz 25 N (17-25). Ballooning the stent after deployment improved fixation in some cases. CONCLUSIONS: a sutured anastomosis fixates a graft better than any stent design tested. Hooks and barbs improve the fixation of self-expandable stents. Balloon dilatation of the proximal stent after deployment might increase fixation further. Balloon expandable stents seem to provide good fixation without the use of hooks and barbs.
Aged↗
Midterm changes in aortic aneurysm morphology after endovascular repair.
PURPOSE: To study midterm changes in aortic aneurysm morphology after endovascular aneurysm repair. METHODS: Of 94 patients with abdominal aortic aneurysms (AAAs) treated with endografts between November 1993 and August 1998, 84 were available for follow-up. Patients were evaluated preoperatively by spiral computed tomography (CT) and aortography; in follow-up, spiral CT scanning was performed at 1, 3, and 6 months and semiannually thereafter. Measurements of the aneurysm neck diameter, maximum aneurysm diameter, and the distance from the lowermost renal artery to the aortic bifurcation were made preoperatively and in follow-up. RESULTS: Mean follow-up was 17.5 +/- 1.1 months; 56 (67%) patients were followed for 1 year and 28 (33%) for > or = 2 years. There was a median 2-mm increase (interquartile range [IQR] 0 to 3) in neck diameter at 18 months. However, a > or = 3-mm increase was seen in 18 (46%) of 39 patients examined at 18 months (median 4 mm, IQR 3 to 4, p = 0.0001). The maximum AAA diameter decreased by 9 mm (IQR 4 to 16, p = 0.0003) at 24 months, but after 18 months, no further interval decrease was seen. Aneurysms with a persistent endoleak showed either increasing or unchanged AAA diameters. There was no change in the renal artery to bifurcation distance. CONCLUSIONS: The infrarenal aortic neck appears to dilate after AAA endografting, but only in a subset of patients. Shrinkage of aneurysms after successful stent-grafting seems to stop after 18 months, implying that the only indication of late failure in the absence of endoleak might be aneurysm enlargement. Graft-related endoleaks are often associated with an increase in aneurysm diameter.
Aged↗
Quality of life before and after endovascular and open repair of asymptomatic AAAs: a prospective study.
PURPOSE: To assess how patients perceive health-related quality of life (HRQOL) after endovascular and open abdominal aortic aneurysm (AAA) repair. METHODS: Forty-two consecutive patients (33 men; mean age 74 years, range 46-81) were assessed prospectively before and after elective endovascular (n = 21) and open (n = 21) AAA repair. Aneurysm morphology dictated the type of repair. The two patient groups were similar regarding age, gender, comorbidities, and cardiopulmonary function. Data concerning surgical trauma were compiled. The Nottingham Health Profile (NHP) score was used to assess the perceived HRQOL (criteria: pain, mobility, sleep, emotion, energy, and isolation) preoperatively and at 5, 30, and 90 days postoperatively. Specific treatment perception questions were added. RESULTS: One patient from each group died, leaving 40 patients to complete the study. Two patients with open repair and 1 patient with endovascular repair were unfit to answer the questionnaire on day 5. The HRQOL improved at 3 months compared with the preoperative values (p < 0.05). No significant difference was found at any time between the open and endovascular groups regarding the NHP score, although the operative time, blood loss, analgesic use, and hospital stay were significantly in favor of endovascular repair. Reinterventions were required in 5 patients with endovascular and 2 patients with open repair. CONCLUSIONS: In general, 3 months after AAA repair, the perceived HRQOL seems better than before treatment. Perceived HRQOL is similar after endovascular and open AAA repair despite greater surgical trauma in open surgery. This may reflect the higher number of reinterventions following endovascular repair but also difficulties in defining HRQOL.
Aged↗
Aneurysm expansion and retroperitoneal hematoma after thrombolysis for stent-graft limb occlusion caused by distal endograft migration.
PURPOSE: To describe a complication of thrombolytic therapy used to treat graft limb occlusion precipitated by distal migration and kinking of an abdominal aortic stent-graft. CASE REPORT: A 5.5-cm abdominal aortic aneurysm (AAA) in a 66-year-old woman was treated with Vanguard bifurcated stent-graft. At the 1-year follow-up, she complained of left leg claudication. Computed tomography (CT) showed a 36% reduction in maximum AAA diameter, but the stent-graft had migrated distally approximately 5 mm, and the left graft limb was occluded. Thrombolysis was initiated, but after approximately 8 hours, abdominal pain began. Emergent CT scanning revealed rapid aneurysm expansion and a retroperitoneal hematoma. Thrombolytic treatment was stopped; transfusions and thrombogenic drugs were given to restore hemodynamic stability. The aneurysm began to decrease in size. The occluded graft limb had been reopened by the lytic therapy, uncovering a stenosis in the native artery distal to the graft limb. Stent placement restored outflow. The retroperitoneal hematoma resolved over time, and the aneurysm sac shrank to its prelytic diameter. The patient is well with a functioning endograft 18 months after the occlusion (30 months after stent-grafting). CONCLUSIONS: Caution must be taken when using thrombolysis in patients with endovascular aortic grafts because unexpected bleeding complications might arise. Thrombectomy, femorofemoral bypass, or stent or stent-graft extensions might be safer alternatives for treating occluded stent-graft limbs.
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[How reliable is the laboratory? Increased needs of patient-related quality assurance].
Recent developments in medical care and research involve the increased use of immunochemical assays for hormones, tumour markers, vitamins and drugs. External quality assurance programmes using pooled human sera usually fail to detect analytical interference due to substances (e.g. anti-immunoglobulin or anti-ligand antibodies) present in individual serum specimens. The article reports on experience gained during a three-year period when specimens from individual patients attending a thyroid unit were distributed to hospital laboratories in Sweden for analysis. Specimen selection criteria were based on contradictory findings at the initial clinical or laboratory evaluation. The programme has given rise to the formation of a network of the laboratories involved, under the co-ordination of EQUALIS (External quality assurance in laboratory medicine in Sweden).
Antibodies↗
Distal migration of stent-grafts after endovascular repair of abdominal aortic aneurysms.
PURPOSE: To analyze patients after endovascular repair of abdominal aortic aneurysm (AAA) with respect to distal migration of stent-grafts and its underlying causes. MATERIALS AND METHODS: Sixty-five patients underwent endovascular repair between January 1994 and February 1997. There were seven women and 58 men, with a mean age of 71 years (range, 51-84 years). Three patients died in the perioperative period (one of myocardial infarction and two of multiorgan failure) and two patients died within 4 months of the procedure of non-procedure-related causes. In addition, two patients were followed at another hospital. The remaining 58 patients were followed up with spiral computed tomography scans at 1, 3, and 6 months, and biannually thereafter. Angiography was performed at 1 month and 1 year after the procedure and additionally when deemed clinically necessary. Mean follow-up was 29 months (range, 1-49). Migration more than 5 mm was considered significant. RESULTS: Twenty-six patients (45%) showed distal migration of stent-grafts during follow-up. Mean follow-up time at detection of migration was 13 months (range, 1-36 months). Thirteen cases of migration were ascribed to dilatation of the proximal aneurysmal neck during follow-up. Ten cases of migration were ascribed to causes other than neck dilatation or poor patient selection. In three cases, no obvious cause for the migration was found. The migration was complete in eight cases, leading to late conversion to open surgical repair. On two of these occasions, complete migration lead to aneurysm rupture. In addition, four patients received additional stent-grafts as proximal extensions. CONCLUSIONS: Distal migration of stent-grafts after endovascular AAA repair occurred frequently in this series. Dilatation of the proximal aneurysmal neck is a major cause of distal migration of stent-grafts. Improved proximal fixation is needed to secure long-term durability.
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Stent-graft treatment of iatrogenic iliac artery perforations: report of three cases.
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Aged↗
Traumatic aortic rupture and retroperitoneal haematoma--treatment including combined operative and endovascular approach.
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Accidental Falls↗
Percutaneous placement of stents in chronic iliac and aortic occlusive disease.
OBJECTIVES: to evaluate the long-term results of stenting in iliac and aortic occlusive disease and identify factors predicting clinical outcome. DESIGN: retrospective study. MATERIALS AND METHODS: 82 patients (87 limbs) with stenoses (n =63) and occlusions (n =24) in the aortoiliac segment were treated with stents. 81 lesions involved the iliac arteries, 3 the infrarenal aorta and 3 the aortic bifurcation. Primary stenting was performed in 57 limbs (complex stenotic lesions and occlusions). Stents were placed following failed PTA in 30 limbs. Median follow-up was 13.2 months (1-66 months). RESULTS: technical success was 99% and clinical success 89%. Cumulative primary and secondary patency of stented iliac atherosclerotic lesions at 1 and 3 years was 75 and 61%, and 83 and 75% respectively. The factors predicting outcome of primary patency identified in Cox multivariate analysis were ankle-brachial index (ABI) prior stenting (p =0.03) and length of the lesion (p =0. 007). Major non-fatal complications occurred in 7.4% of the patients and there were no deaths attributed to the treatment. The 30-day mortality was 3.7%. CONCLUSION: stenting of complex aortoiliac stenoses and chronic occlusions is a safe and effective treatment modality. Long lesions and lower pre-procedure ABIs were found to negatively influence outcome.
Adult↗
Abdominal aortic aneurysm morphology in candidates for endovascular repair evaluated with spiral computed tomography and digital subtraction angiography.
PURPOSE: To analyze the morphology of abdominal aortic aneurysms (AAAs) and to study the usefulness of spiral computed tomography (CT) versus digital subtraction angiography (DSA) in the evaluation of patients for endovascular repair. METHODS: Of 133 AAA patients (120 men, mean age 67 years, range 52 to 84) evaluated preoperatively with CT imaging, 77 endograft candidates (68 men) were also assessed with intra-arterial DSA. Arterial parameters were measured on axial CT scans and angiographic films for comparison. RESULTS: Mean maximum AAA diameter was 58 +/- 11 mm (range 39 to 95). Aneurysmal neck diameter was consistently smaller on DSA than on CT (20.7 +/- 3.6 mm versus 23.0 +/ 3.5 mm, p < 0.0001). The distance from the most distal renal artery to the aortic bifurcation was longer on angiography than on CT (mean difference 10.0 mm, p < 0.0001). There was a positive correlation between the maximum AAA diameter and the AAA length (r = 0.49, p < 0.0001) and an inverse relationship between the neck length and the neck diameter (r = -0.36, p < 0.0001). No correlation was found between the maximum AAA diameter and maximum iliac diameter, angulation, or length. CONCLUSIONS: AAA anatomy varies widely and independently of the aneurysm size. Therefore, the maximum size of the aneurysm is a poor predictor of whether or not an aneurysm is suitable for endovascular repair. The discrepancy between angiographic and axial CT measurements suggests that neither alone is sufficient as a preoperative imaging technique when evaluating a patient for an endovascular graft procedure.
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Endovascular management of the juxtarenal aortic aneurysm: can uncovered stents safely cross the renal arteries?
A short or otherwise suboptimal neck precludes the use of endovascular repair in 30% to 50% of patients with abdominal aortic aneurysms. Stent-graft fixation in an unsuitable neck carries the risk of technical failure owing to development of a proximal endoleak or stent-graft migration. Furthermore, in some patients, the neck dilates postoperatively. Endovascular healing with tissue incorporation into the graft material seems in and of itself insufficient to fixate the stent-graft adequately or to prevent neck dilation. Therefore, neck dilation is often associated with detachment of the stent-graft from the aortic wall, which is followed by the development of a proximal endoleak or stent-graft migration. Fixation of stent-grafts can be improved by placing the proximal stent above one or both of the renal artery orifices. Current experimental and clinical data suggest that renal function is not impaired by suprarenal aortic stents during the first year; however, this finding may not apply to all types of stents. Fixation of stent-grafts also may be improved by using stents with barbs that pierce the aortic wall. Additionally, the force that is exerted on the anchoring device may well be reduced by fully stented grafts with an associated increase in column strength. In the future, the risk of neck dilation and stent-graft dislodgement might also be limited by novel techniques such as laparoscopic banding of the neck or endoluminal stapling devices.
Aortic Aneurysm, Abdominal↗
[Chronic mesenteric ischemia. Endovascular treatment is as effective as open surgery].
Chronic mesenteric ischaemia is a rare but serious condition, which if untreated may cause death secondary to starvation or bowel infarction. As the symptoms are sometimes unspecific, its diagnosis may be delayed or missed. Although open surgical revascularisation has been the traditional treatment, a review of published reports suggests it to be associated with operative mortality rates of 6-9 per cent, and major morbidity rates of 22-26 per cent. Reports by others, and our own experience, suggest that endovascular treatment of mesenteric atherosclerotic obstructions with PTA (percutaneous transluminal angioplasty) and stenting may yield patency rates differing little from those associated with surgery, but significantly lower mortality (1.6%) and morbidity (5.6%).
Angioplasty, Balloon↗
Aggressive treatment of acute limb ischemia due to thrombosed popliteal aneurysms.
OBJECTIVE: The absence of infra-popliteal runoff in patients with acute limb ischemia and thrombosed popliteal aneurysms carries a high risk of amputation. A combined treatment method involving thrombolysis and surgery is reported. MATERIAL AND METHODS: Information regarding six patients was reviewed. Ankle brachial indices and degree of ischemia were recorded. All patients underwent digital subtraction angiography. In five patients thrombus dissolution was achieved using a combination of mechanical and pharmacologic therapy. One patient was judged incapable of withstanding any delay in reperfusion and was treated with isolated limb perfusion using a thrombolytic agent. All patients underwent surgical revascularization. Follow-up (1-3 years) consisted of duplex examinations at 6 months and yearly thereafter. RESULTS: Five patients had no measurable ankle brachial index (ABI), while one patient had an ABI of 0.4. Initial angiography noted all patients to have no runoff in continuity to the pedal arch. Following thrombolytic therapy, an adequate bypass vessel was noted in all cases, with reconstitution of the plantar arch in five patients. Distal revascularizations included one peroneal, and five below knee popliteal arterial bypasses. Fasciotomies were performed in four of the six patients. There were no amputations. One patient developed a persistent foot drop. Two patients developed bypass grafts occlusions; one of which required therapy. CONCLUSION: The pre-operative use of thrombolytic therapy is a safe and effective method to achieve limb salvage in this patient population. Patients must be capable of withstanding an additional period of ischemia allowing for reconstitution of distal runoff. Isolated limb perfusion is of use when a delay to reperfusion cannot be tolerated.
Acute Disease↗
Activated protein C resistance in patients with peripheral vascular disease.
PURPOSE: The frequency of activated protein C (APC) resistance, caused by factor V R506Q gene mutation and abnormal APC ratio, in patients with peripheral vascular diseases was analyzed. METHODS: All patients electively admitted to the vascular ward unit of our tertiary care academic medical center from January 1995 through October 1996 (n = 679) were prospectively analyzed using an APC-resistance screening test to determine the frequency of abnormal APC ratio (< or =2.6). Baseline activated partial thromboplastin time (APTT) and its prolongation after the addition of a standard amount of APC were determined. The factor V R506Q gene mutation (Leiden) was analyzed in patients with an APC ratio less than 3.0. Statistical comparisons were made to an age-matched control population (n = 278). RESULTS: The factor V Leiden gene mutation or abnormal APC ratio was detected in 154 of the patients (22.7%), compared with 34 of 278 the control subjects (12.2%; t = 13.65; P < .001). The factor V Leiden gene mutation was found in 102 patients (15.2%), compared with 29 control subjects (10.4%; t = 4.64; P < .05); an abnormal APC ratio was found in 132 patients (19.8%), compared with 26 (9.8%) of controls (t = 14.56; P < .001). The frequency of the factor V Leiden gene mutation was significantly increased in patients with femoro-popliteal occlusive disease (n = 126), to 21.6% (t = 16.94; P< .001), and venous disease (n = 50), to 36.0% (t = 20.93; P< .001). Overall, 63% of the patients with abnormal APC ratios tested positive for the factor V Leiden gene mutation. A significantly increased frequency of APC resistance was demonstrated in patients undergoing aorto-iliac (n = 37) or femoro-crural graft reconstructions (n = 72); it was found in 41% and 35%, respectively (P < .001). In addition, a significantly increased frequency of APC resistance was found in patients who suffered from occlusion after reconstruction; 13 of 41 (32%) had the factor V Leiden gene mutation (P < .001), and 19 of 39 (49%) had an abnormal APC ratio (P < .001). CONCLUSION: The factor V Leiden gene mutation and abnormal APC ratios are significantly increased in patients with lower extremity peripheral vascular disease and failed reconstructions. An abnormal APC ratio was seen without factor V Leiden gene mutation in 37% of patients with peripheral vascular diseases, suggesting additional causes of an abnormal APC ratio, exclusive of gene mutation.
Activated Protein C Resistance↗
Persistent collateral perfusion of abdominal aortic aneurysm after endovascular repair does not lead to progressive change in aneurysm diameter.
PURPOSE: To differentiate between the phenomenon of collateral perfusion from a side branch versus graft-related endoleaks after endovascular repair of abdominal aortic aneurysms (AAA), with respect to aneurysm size and prognosis. METHODS: We successfully treated 64 AAA patients with endovascular grafting. We followed all the patients postoperatively with spiral computed tomography at one, three, six and 12 months, and biannually thereafter. We measured aneurysm diameters preoperatively and postoperatively. We calculated preoperatively the relation of maximum aortic diameter (D) to the thrombus-free lumen diameter (L) expressed as an L/D ratio. Median follow-up was 15 months. RESULTS: Sixteen patients had collateral perfusion during follow-up. We successfully treated two patients with embolization. One patient showed resolution of collateral perfusion after we stopped warfarin treatment. Two patients died of unrelated causes during follow-up. One patient was converted to surgical treatment, and two patients showed spontaneous resolution of their collateral perfusion. The group of patients with perfusion showed no statistically significant change of their aortic diameter on follow-up. The group of patients without perfusion showed a median decrease in aortic diameter of 8mm (p < 0.0001) at 18 months postoperatively. The group of patients with perfusion had significantly less thrombus in their aneurysm sac preoperatively than the group without perfusion, as expressed by the L/D ratio (mean L/D 0,61 versus 0,78, respectively; p=0.0021.) CONCLUSION: There was no significant increase in aortic diameter on an average 18 months postoperatively despite persistent collateral perfusion. This may indicate a halted disease progression in the short term. Embolization of collateral vessels is associated with risk of paraplegia. We recommend a conservative approach with close observation if aneurysm diameter is stable.
Adult↗