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Biomedical subjects

D Raithel

Publications and source records attributed to D Raithel.

At least 19 recordsLinked to original sources
PubMed2003

Graft patency and clinical outcome of femorodistal arterial reconstruction in diabetic and non-diabetic patients: results of a multicentre comparative analysis.

OBJECTIVE: in diabetic patients with critical limb ischaemia (CLI) an inferior success rate following infrainguinal bypass surgery is quite often suggested. The aim of this retrospective analysis was, therefore, to evaluate the graft patency and, particularly, the clinical outcome at 1 year in diabetic compared with non-diabetic patients. MATERIAL AND METHODS: two hundred and eleven patients (diabetics 94; non-diabetics 117) with femorodistal reconstruction for CLI were studied. Groups were comparable with regard to the Fontaine classification, the distribution of vascular risk factors, graft material, distal anastomosis site, and the angiographic runoff grading. RESULTS: diabetes did not adversely affect graft function. For diabetics and non-diabetics primary cumulative patency rate at 1 year was found to be 66 and 56%, respectively (p=0.10) and a virtually identical limb salvage rate of 85 and 83% was achieved (p=0.76). With regard to healing of ischaemic foot ulcers a trend against diabetics was noted with a healing rate of 81% compared to 96% in non-diabetics at 1 year (p=0.067); gangrenous foot lesions could be equally remedied in 94% and in 87% among patients with and without diabetes (p=0.44). The survival rate of diabetics, however, was significantly lower with 78% at 1 year compared with 95% in non-diabetic patients (p=0.0004). CONCLUSIONS: our preliminary results support the view that infrainguinal bypass grafting can be safely done even in diabetics. Despite increased mortality in this group, liberal indication for reconstructive vascular surgery seems to be justified by favourable patency rates and clinical outcome in selected patients.

Aged↗
PubMed2002

[Results of endovascular Abdominal Aortic Aneurysm Repair (EVAR)].

Endovascular surgery for abdominal aortic aneurysms (AAA) has been performed with different commercially available devices since more than 7 years. The technique of implantation even for ruptured aneurysm is feasible. Attention is now focused on complications and mid-term results. We present a single center experience over the last 7 years using nine different endografts. 653 patients with AAAs were treated endovascularly (158 tubes, 495 bifurcated) between August 1994 and September 2001. The total mortality rate in the follow-up period (median 37 months) was 6.1 % with a 30-day mortality of 0.76 % and a procedure-related lethality of 1.2 %. Tube endografts showed the highest endoleakage rate (37.3 %) due to secondary shortening, migration and material defects. Endoleakage was diagnosed in 18.2 % of unibody designed stentgrafts versus 28.3 % in modular grafts. Regarding proximal Type I endoleaks suprarenal fixation with uncovered stents seems to be of no further advantage in proximal graft fixation. The conversion rate was 6.6 % (n = 43), aneurysm rupture following endovascular repair occurred in 3 of these patients (0.45 %). Mortality in emergency conversion was 30 % compared to no deaths in elective cases. There was a surprisingly high rate of inadvertent renal infarctions (9 %) in follow-up CT scans, two times higher in suprarenal fixation (18 %) than in infrarenal position (7.4 %). In conclusion, we observed best results in unibody bifurcated stentgrafts, late failure of first generation endografts (Mintec(R)) and decreasing conversion rates over the last years (learning curve!). The clinical significance of a side branch endoleak and related maximal AAA diameter remains uncertain. The ideal graft has yet to be found, but improvements in design and implantation techniques evolve rapidly. Good results will be obtained in the future by patient selection and restrictive indications.

Adult↗
PubMed2000

[Conventional aortic surgery after endovascular aortic reconstruction].

INTRODUCTION: Endovascular therapy of aortic aneurysms is an attractive alternative to conventional aortic surgery. A number of patients, however, will fail endovascular therapy and require open surgical repair. METHODS: We report our experience with conversion to open aortic repair. Of 306 patients given endovascular therapy for an infrarenal aortic aneurysm, 30 (9.8%) required conversion to conventional repair. RESULTS: Thirteen patients (43.3%) suffered complications, 3 (10%) of which were fatal. Conversion to open aortic repair after endovascular therapy is technically more demanding than primary open repair, particularly because of clamp techniques and stent-extraction. CONCLUSIONS: Emergent conversion operations, especially when preceded by significant retroperitoneal bleeding from vascular tears due to endovascular manipulations are complicated by significant morbidity and mortality.

Adult↗
PubMed2000

Aortic aneurysm size and graft behavior after endovascular stent-grafting: clinical experiences and observations over 3 years.

PURPOSE: To assess the long-term safety and efficacy of aortic endografts in terms of clinical outcome, continuing aneurysm exclusion, and changes of aneurysm size and graft configuration. METHODS: Between August 1994 and July 1997, 190 patients (176 men; mean age 68.7 years, range 40-87) with aortic and aortoiliac aneurysms were treated with endovascular stent-grafts (Stentor, Vanguard, and EGS) in a tertiary care municipal hospital setting. Follow-up involved clinic visits every 3 to 6 months with contrast-enhanced computed tomography (CT), color duplex, and plain abdominal radiographs at regular intervals; angiography was used selectively. All data were collected prospectively and entered into a computerized database. RESULTS: Implantation was possible in 188 (98.9%) patients. Early conversion to open surgical repair was required in 14 (7.4%) patients. Primary endoleaks were detected in 32 (16.8%) patients. Perioperative mortality was 0.53% (1/190). During follow-up, 17 (8.9%) additional patients were converted to open repair over a mean 20.9 months. Thirty-seven secondary procedures to treat endoleaks and pelvic outflow occlusions were performed in 30 (15.8%) patients. Changes in stent configuration suggestive of endograft disintegration were observed in 31 (29.8%) of 104 abdominal radiographs. Intraluminal layering of thrombus was seen on contrast-enhanced CT images in 20 patients. A significant trend (chi(2)4 = 12.34, p < 0.025) toward aneurysm enlargement was seen in patients with persistent endoleaks at a mean 18-month follow-up. CONCLUSIONS: Although endoleaks after aortic stent-graft placement tend to cause ongoing aneurysm growth, we have also observed aneurysm shrinkage despite ongoing endoleak. The presence or absence of an endoleak in itself may be a poor predictor of successful stent-graft therapy. Lifelong surveillance is needed to assure successful aneurysm exclusion and stability or shrinkage of the aneurysm sac. Technical improvements in stent materials and design are necessary to guarantee long-term stability and safety of the device.

Adult↗
PubMed2000

[Eversion endarterectomy--out?].

Carotid eversion endarterectomy has become a well established alternative to conventional carotid endarterectomy. Similar perioperative morbidity and mortality results have been documented in several large clinical series. Our experience with carotid reconstructive surgery consists of 12,596 operations between 8/84 and 12/97, some 60% of which were performed using the eversion technique. Transient or permanent neurologic deficit was observed in 2.0%; 0.8% died after the procedure. Eversion endarterectomy should only be performed under suitable anatomic conditions. It is a challenging technique which requires advanced surgical skills and sound clinical judgement. The long-term rate of restenosis seems to be influenced favourably after eversion endarterectomy.

Blood Vessel Prosthesis Implantation↗
PubMed2000

[Treatment of restenosis].

Carotid restenosis after endarterectomy is observed in up to 24.1% of patients with long-term follow up. Indication for reintervention in asymptomatic patients however should be reserved for greater than 80% stenosis. Treatment options include repeat surgical reconstruction as well as intraoperative or percutaneous balloon angioplasty +/- stenting. We compared our past experience with 66 operative reconstructions in 64 patients with a recent series of 60 patients who underwent intraoperative balloon-dilatation and stenting. After conventional surgery 2 patients (3.1%) suffered a permanent neurological deficit, one patient developed a TIA (1.5%). After intraoperative dilation and stenting 8 patients (13.3%) suffered a stroke; 2 patients died after surgery (one stroke, one myocardial infarction) (mortality 3.3%). When compared to conventional operative repair intraoperative carotid balloon angioplasty and stenting of restenosis is complicated by a substantial increase in morbidity and mortality and cannot be recommended as routine therapy.

Angiography, Digital Subtraction↗
PubMed1999

Frame dislocation of body middle rings in endovascular stent tube grafts.

OBJECTIVES: To understand the cause, and propose a mechanism for frame dislocation in endovascular grafts. MATERIALS AND METHODS: Five tube grafts were explanted due to secondary distal leakage 15-21 months after operation. One bifurcated graft was removed during emergency operation after aortic rupture caused by secondary leakage. A second bifurcated graft was harvested from a patient with thrombotic occlusion of one limb, who died after transurethral prostatic resection. The inside of the grafts were examined endoscopically. The stent was inspected after removal of the fabric, broken ligatures were counted and examined by scanning electron microscopy. The fabric strength was tested by probe puncture. RESULTS: We found 17-44% of the stent ligatures of the body middle rings to be loose. The knots were intact. Degradation of the polyester textile was not observed. CONCLUSIONS: Continuous movements in the grafted aorta and blood pressure impose permanent stress to the stent frame and the polyester fabric resulting in morphological changes in the body middle ring of grafts. The clinical implications of the suture breakages are unknown although they may be related to distal secondary leakage in tube grafts.

Aortic Aneurysm, Abdominal↗
PubMed1998

[Imaging of aortic endoprostheses and their complications].

PURPOSE: To determine the optimal postoperative imaging modality for the follow-up of patients with endoluminal aortic stent grafts. MATERIAL AND METHODS: From August 1994 to November 1997, 214 patients (194 male and 20 female) with abdominal and thoracic aortic aneurysms were treated with endovascular stent grafts. 137 patients (129 male, 8 female) with 89 tube grafts and 48 bifurcated grafts (45 EVT, 88 Stentor/Vanguard, 3 Chuter, 1 Talent) were evaluated with contrast-enhanced spiral-CT, duplex ultrasound, and DSA at a mean follow-up of 11.1 months. RESULTS: We found 12 persistent primary endoleaks (8.8%), 17 secondary endoleaks (12.4%), 8 limb occlusions (5.8%), 28 endoluminal thrombi lining the stent graft (20.4%), and 26 suture breakages of the stent frame (19%). In 9 patients (6.6%) the proximal end of the stent partially covered the renal arteries. In 3 patients (2.2%) a partial renal infarction was seen. Spiral-CT was able to demonstrate all the above changes except for 3 sidebranch endoleaks that were documented by duplex ultrasound only and 8 suture breaks seen on abdominal plain films only. The median aneurysm diameter decreased from 48 mm pre-operatively to 46 mm at 24 months post-operatively in patients with endoleaks and from 44 mm to 36 mm in patients without endoleak. For several patients the decreasing aneurysm diameter did not reliably correlate with complete exclusion of the aneurysm. CONCLUSION: For follow-up of endoluminal aortic stent grafts contrast-enhanced spiral-CT is superior to duplex ultrasound. DSA is necessary only for patients with complications requiring a secondary intervention.

Adult↗
PubMed1998

[Endovascular exclusion of abdominal aortic aneurysm].

OBJECTIVE: To explore the indications, methods, manipulations, and problems of endovascular exclusion of abdominal aortic aneurysm (AAA). METHOD: Under general anesthesia and dynamic supervision of DSA, an endovascular exclusion with a stent-graft complex of 11.0 cm x 2.6 cm was successfully performed on a 70-year-old man contraindicated for major open surgery with AAA of 10.0 cm x 6.0 cm and an AAA neck of 2.5 cm x 1.6 cm. RESULT: The patient was up and about on the first postoperative day. Duplex scan (by the end of the first postoperative week) and CT (on the postoperative 20th day) revealed a completely excluded AAA by the stent-graft that was patent and had an inner diameter of 2.2-2.4 cm, without migration and torsion. The primary AAA sac was full of thrombi and no patent lumbar and inferior mesenteric arteries were observed. The external diameter of AAA was unchanged, renal and iliac arteries were all patent, but a micro-crevice between the proximal end of the stent-graft and the anterior wall of the AAA neck was revealed. Six months postoperative follow-up showed that the patient's abdominal pulsatile mass and the left lower extremity's claudication disappeared. CONCLUSION: Endovascular exclusion of AAA is of great practical value.

Aged↗
PubMed1998

Surveillance of patients after abdominal aortic aneurysm repair with endovascular grafting or conventional treatment.

At Nuremberg Southern Hospital we have been using endovascular therapy for aortic aneurysms for the past 3 years. Between August 1994 and August 1997, 193 patients with infrarenal aortic aneurysms were treated with endovascular stent grafts. Besides using commercially available modular systems of the Stentor type (MinTec/Vanguard*, Boston Scientific) we also participated in a multicenter study implanting EGS devices (EVT in 65 patients). Follow-up examinations must strive to detect thrombotic complications as well as endoleaks with high sensitivity and specificity. To avoid aneurysm rupture significant increase in aneurysm diameter must be detected in a timely fashion to select patients for additional corrective endovascular procedures or conversion to open surgical therapy. A close follow-up regimen therefore is absolutely mandatory for all patients undergoing endovascular aortic grafting, particularly when new prosthetic devices are being introduced. Prosthetic devices that have been adequately tested using controlled study designs and are commercially available may be followed-up using a standardized follow up scheme as delineated. Particularly during the first postoperative year color duplex with use of an intravenous ultrasound enhancing agent has been used successfully to detect even minor endoleaks originating from retrograde perfusion via aortic side branches (lumbar or inferior mesenteric artery). Only patients with documented endoleaks or suspected outflow obstruction requiring further intervention need to undergo diagnostic arteriography. After conventional aneurysm repair yearly duplex scans are usually sufficient to follow the normal patient. Patients who have undergone endovascular therapy, however need to be followed much closer using duplex as well as abdominal CT scans. This will logically result in significantly higher follow up costs. Periinterventional costs of endovascular aortic reconstruction currently exceed those of conventional aortic repair by approximately 50%. Given the current health care finance situation it is questionable whether endovascular therapy of abdominal aneurysm will become standard practice in Germany.

Aged↗
PubMed1997

[Arterial vascular lesions after total hip joint replacement].

We report on three arterial thromboses of the external iliac artery following total hip replacement. As a result of implanted cement/spongiosa or protrusion of the acetabular component, the iliac vessels were compressed. Furthermore, we report about one intraoperative arterial vessel lesion in a 65-year-old patient during a revision operation. We recommend that in case of acute ischemic syndromes of lower limbs following total hip replacement, an angiography should be performed in order to exclude an extravascular cause of thrombosis. For therapy in those cases extra-anatomic bypasses should be preferred to thrombectomies.

Aged↗
PubMed1997

Bifurcated stent-graft for abdominal aortic aneurysm.

The purpose of this study was to examine bifurcated stent-graft implantation for abdominal aortic aneurysm. Fifty-seven patients were treated and followed with serial computed tomography scans for up to 3 years. Patients were allocated to three groups (first 20, second 20, last 17) according to when the repair was performed. Successful treatment is defined as exclusion of the aneurysm from the circulation, based on contrast computed tomography. Success rates in the three groups were 55%, 70% and 100%. Perigraft leak (endoleak) was present on initial assessment in 4/20, 2/20 and 1/17. Two of these aneurysms ruptured early in the postoperative period. Thereafter, leaks were sought and treated aggressively. Kinking and thrombosis occurred in six of the first 20 patients, but did not occur in any of the last 37 patients, in whom the graft limbs were routinely stent-supported throughout. Infrarenal implantation in very a short neck (< 10 mm), or a thrombus-lined neck was associated with proximal stent migration. In conclusion, changes in patient selection and technique have led to a steady rise in the short-term success rate of the stent-grafted implantation.

Aneurysm, Ruptured↗
PubMed1997

European experience with a system for bifurcated stent-graft insertion.

PURPOSE: To test an endovascular aneurysm exclusion system in the presence of a wide range of challenging anatomic features. METHODS: Bifurcated endovascular stent-grafts were inserted in 52 patients and followed with serial computed tomography for up to 3 years. The device underwent several modifications during this time, the most significant of which represent the difference between the homemade (n = 42) and industry-made (n = 10) versions. RESULTS: The initial procedural success rate was 92% in the homemade group and 100% in the industry-made group. In the 3 years of follow-up, the long-term success rate was 64% in the homemade group and 90% in the industry-made group. The primary reasons for failure in the homemade group were graft thrombosis due to kinking early in the series and proximal stent migration later in our experience. All cases of migration occurred when the neck was < 15 mm in length, the neck was lined with thrombus, or the stent was implanted > 15 mm from the renal arteries. Kinking was subsequently overcome by implanting Wallstents throughout the graft limbs. The sole failure in the industry-made group was a case in which collateral perfusion reached the aneurysm through patent lumbar arteries. CONCLUSIONS: The fruits of this experience are a better technique, a better device, and, most importantly, a better understanding of the system's limits, as reflected in the current selection criteria.

Angiography↗
PubMed1997

Postoperative color flow duplex scanning in aortic endografting.

PURPOSE: To report the feasibility and sensitivity of duplex sonography compared to computed tomography (CT) for aortic endograft follow-up surveillance. METHODS: In a 26-month period, 113 aortic aneurysm patients received 79 tube and 34 bifurcated stent-grafts. Follow-up used contrast-enhanced CT scanning and duplex sonography with an intravenous ultrasound contrast agent (Levovist). RESULTS: Eleven patients (9.7%) were converted to open repair; 1 died from hemorrhagic shock secondary to retroperitoneal hematoma. The mean follow-up time was 7.2 months (range 1 to 24), during which 5 patients died of unrelated causes. Sixteen primary (within 30 days) and 5 secondary endoleaks were detected by duplex after tube graft implantation. Among 5 endoleaks due to retrograde side-branch perfusion, 3 were detected only with contrast-enhanced duplex scanning. Iliac artery occlusion was also documented using duplex; however, 2 stent fractures could not be seen with ultrasound. Ten primary endoleaks were detected in bifurcated stent-graft patients. One endoleak originating from the distal iliac limb anchoring site was missed by duplex owing to bowel gas. Graft limb thrombosis was clearly identified by lack of a flow signal on duplex. CONCLUSIONS: Duplex sonography could be a valuable, reliable, and economical surveillance tool for endovascular aortic reconstructions. The adjunctive use of an intravenous ultrasound contrast agent increased the sensitivity for detecting endoleak to a level comparable to contrast-enhanced CT scanning. However, stent fractures may not be seen on ultrasound, and bowel gas can interfere with obtaining an adequate image.

Adult↗
PubMed1997

[Results and complications after endovascular reconstruction of aortic aneurysms].

Between August 1994 and December 1996 137 patients (10 female and 127 male, mean age 66 yrs., range 27-85) with aortoiliac aneurysmal disease were treated with endovascular stent grafts. Pathology included 5 thoracic, 131 abdominal and 1 isolated iliac artery aneurysm. 88 straight tube grafts (75 Mintec, 12 EVT, 1 Chuter) and 43 bifurcated grafts (21 Mintec, 20 EVT, 2 Chuter) were implanted in the infrarenal aorta. 5 (Mintec) tube grafts were used for the thoracic aneurysms. One tapered tube graft was used to exclude the isolated iliac aneurysm. 11 patients (8%) required conversion to open surgical repair. This was due to defective devices in 5, device related occlusion of a renal artery in 2, aortic dissection in 1, occlusion of iliac outflow in 1, a large unmanageable proximal endoleak in 1 and a retroperitoneal bleeding resulting in hemorrhagic shock in 1 patient. There was one procedure related death for a mortality of 0.7%. Patients were followed every 3-6 months using CT with i.v. contrast and ultrasound duplex examinations with adjunctive usage of an intravenous ultrasound contrast agent (Levovist, Schering AG). Intraarterial DSA was used only when called for by thrombotic or stenotic complications. At a mean follow-up of 9.2 months (range 2-24 months) 16 (17%) primary and 8 (8.5%) secondary leaks (at the distal anchoring zone) were detected after implantation of tube grafts. 11 (25.6%) leaks were detected after implantation of bifurcated grafts. Iliac artery occlusion was observed in 2 patients after placement of a straight endograft, 6 times after reconstruction with a Mintec bifurcated device and 3 times after implantation of an EVT bifurcated endograft. Successful treatment of iliac artery occlusion without the need for subsequent amputation or major disability included extraanatomic bypass in 7 patients, PTA (3 patients) and implantation of wallstents (2 patients) or conservative management (1 patient).

Adult↗
PubMed1996

Recurrent carotid disease: optimum technique for redo surgery.

Carotid restenosis has been a well-recognized, though not well-understood, long-term complication of carotid endarterectomy. Various factors contribute to recurrent stenosis, but the chief cause is technical faults during the primary procedure. Redo endarterectomy or graft reconstruction are the traditional and most effective procedures for treating symptomatic or high-grade (> 80%) asymptomatic restenotic lesions. To reduce the potential for carotid restenosis, eversion endarterectomy is recommended as the technique of choice for de novo carotid disease treatment. Angioscopy is useful in detecting correctable technical errors that could predispose to restenosis.

Angioscopy↗