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Biomedical subjects

K H Orend

Publications and source records attributed to K H Orend.

At least 19 recordsLinked to original sources

[Thorax injuries].

Thorax injuries may be divided etiologically into blunt and penetrating types, depending on the nature of the insult. In European practice, the former predominates by far, and in only about 5% of cases thoracotomy provides the necessary thorax drainage. Morbidity in this type of injury typically involves concomitant lung contusion, sometimes with fatal acute respiratory distress syndrome. In these cases, special ventilation forms, optimal reduction of pain, and organ replacement are the decisive therapeutic methods. In contrast, about 80% of penetrating trauma to the thorax require prompt transpleural or trans-sternal surgery, depending on the type of injury. Emergency first aid must follow the principle of "scoop and run". Each minute elapsed until emergent thoracotomy can be decisive to survival in these cases, and the fastest possible transport from the place of injury takes priority over time-consuming stabilization.

Contusions↗

[The vascular surgeon's role in intensive care].

The role of vascular surgeons in the intensive care unit includes two major tasks: (1) consultant activity in complications of different operative specialties, for instance postoperative venous thrombosis after Wertheim's operation, mesenteric superior artery embolus, or arterial injury after total prosthetic replacement of the hip, (2) postoperative care following vascular surgery in order to identify and treat specific complications such as limb ischemia after reconstructive surgery, compartment monitoring after reperfusion injury of the aorta or extremities, carotis monitoring after postoperative apoplexy, and subsumed identification and treatment of ischemic and postischemic states in organs and tissues. Keeping vascular reconstructive options open is particularly important for polytrauma patients with blunt or open vascular injuries beginning from the thoracic aorta ending with subtotal amputation of the lower leg. Vascular surgeons in an intensive care setting play the central role in setting diagnostic course and therapy measures, while organ substitute therapy is within the administrative jurisdiction of the intensivist. Considering the complexity of morbidity in vascular patients, consultation by the intensivist, cardiologist, and neurologist is warranted.

Critical Care↗

Stentgrafting of the thoracic aorta-complications.

Endovascular therapy (EVT) of thoracic aortic pathologies meanwhile is an established procedure with favourable midterm results in high risk patients. Different stent fabrications are available with defined flexibility, radial attachment force, metallic stent components and membrane porosities. Recent approval of the TAG Excluder (Gore) by the Food and Drug Administration (FDA) was an important step. Endoleaks, paraplegia, stroke and retrograde dissections are the main specific complications. Type I endoleak incidence rates are related to morphological case complexity; primary frequency rates of 0-20% are reported in the literature with 0-5% secondary incidence. Creating an appropriate proximal neck -- if necessary by supra-aortic branch remodelling -- and deliberate left subclavian artery overstenting is the key mechanism to avoid proximal endoleaks. Paraplegia rates are reportedly low with EVT in the range of 0-5%. Risk situations are: cases of rupture with compromised blood pressure, cases with a history of abdominal aortic aneurysm (AAA) exclusion, cases who require total overstenting of the descending thoracic aorta. The role of cerebrospinal fluid (CSF) drainage in EVT is not defined. Stroke as consequence of embolizing material from central endoaortic manipulations is almost in the same range as paraplegia, when morphologies in the distal arch are attacked. Retrograde dissection is reported not only after treatment of type B dissection but also after aneurysms. Rigid bare springs and ballooning in cases of type B dissection seem to be involved. In recent reports mortality in elective cases varies between 1.5% and 6.5%. All these data are promising but the proof of longterm durability is still lacking. Further development will show whether or not these preliminary data will translate into longterm success.

Aortic Dissection↗

[Interdiscplinarity in thorax operations-from the viewpoint of the surgeon].

Occasionally, thoracic interventions may require interdisciplinary teamwork with plastic surgery, heart and vascular surgery, or neurosurgery. Thoracic wall defects following excision of primary wall tumors or recurrent, ulcerating tumors of the breast may require full-thickness myocutaneous flaps, which can best be done with the help of plastic surgeons. In case of infiltration of the heart or thoracic aorta, the en bloc principle of T4 lung tumors occasionally requires the help of heart surgeons, for open atrial resection using the heart-lung machine, or vascular surgeons for aortic graft interposition. Paravertebral dumbbell tumors occasionally may infiltrate to the intraspinal space and therefore need removal by neurosurgeons. When and why other specialists are required for an interdisciplinary approach to diseases of the chest has not been clearly defined. Therefore it is wise to gain informed consent from the patient about the roles of different specialists in interdisciplinary treatment for his disease.

Aged↗

Endovascular treatment in diseases of the descending thoracic aorta: 6-year results of a single center.

OBJECTIVE: The purpose of this study was to evaluate endovascular treatment in diseases of the descending thoracic aorta. MATERIAL AND METHODS: This study was designed as a single center's (university hospital) experience. Over a 6-year period (1995 to 2001), thoracic endografts were placed in 74 patients with a diseased descending thoracic aorta who were at high risk for conventional open surgical repair: 34 had atherosclerotic aneurysms, six had posttraumatic aneurysms, 14 had type B dissection with aneurysmal dilatation of the false lumen, 12 had isthmic transections from blunt trauma, five had thoracoabdominal aneurysms (treated with a combined procedure), two had aortic coarctation, and one had an aortobronchial fistula. Twenty-six procedures (35.1%) were conducted as emergencies, and 48 (64.9%) were elective. The feasibility of endovascular treatment and sizing of stent grafts were determined with preoperative spiral computed tomography and intraoperative angiography. RESULTS: Endovascular operations were completed successfully in all 74 patients; postprocedural conversion to open repair was necessary in three cases. The overall 30-day mortality rate was 9.5% (seven deaths). Temporary neurologic deficits developed in two patients; not one patient had permanent paraplegia. The primary endoleak rate was 20.3% (15 patients). The mean follow-up period was 22 months (range, 3 to 72 months). Five deaths occurred in the follow-up period, and three patients needed secondary conversion to open repair 2, 3, and 14 months after initial endografting. CONCLUSION: Endoluminal treatment in diseases of the thoracic descending aorta is feasible and may offer results as good as the open method.

Adolescent↗

Treatment of thoracoabdominal aortic aneurysms with a combined endovascular and surgical approach.

AIM: The conventional approach for the repair of thoracoabdominal aneurysms remains complex and demanding and is associated with substantial morbidity and mortality. Moreover, in cases of reoperation the impact can be dramatic either in survival or in quality of life of the patients, albeit the use of adjuncts. A combined endovascular and surgical approach with retrograde perfusion of visceral and renal vessels has been realized in order to minimize intraoperative and postoperative complications. METHODS: Within an experience of 231 aortic stent-grafts between 1995-2000, 4 of the patients with thoracoabdominal aneurysms were treated with a combined endovascular and surgical approach. Three procedures were electively conducted and 1 on emergency basis. Two women, 59 and 68 years old, and 2 men, 68 and 73 years old (maximum aneurysm's diameter was 10, 6, 8 and 9 cm, respectively) were operated with the combined method (the first 2 patients had a previous open repair of a thoracoabdominal aneurysm). The surgical approach was executed in all patients without thoracotomy or re-do retroperitoneal exposure. Revascularization of renal, superior mesenteric (and celiac in 2 cases) arteries was accomplished via transperitoneal bypass grafting. Aneurysmal exclusion was performed by stent-graft deployment. RESULTS: The entire procedure was technically successful in all patients. The 1(st) patient was discharged 6 weeks after the operation, while the postoperative studies revealed the patency of the vessels and no evidence of leak or secondary rupture of the aneurysm; the patient died 3 months after the repair, due to rupture of an aneurysm of the ascending aorta. In the 2(nd) patient, 30 months after the operation, spiral-CT scanning revealed distinct shrinkage of the aneurysm, no graft migration or endoleak and patency of all revascularized vessels. The 3(rd) patient died on the 6th postoperative day due to multiorgan failure after having developed ischemic-related pancreatitis, albeit the successful combined repair. The 4(th) patient followed an uneventful course. No patient experienced any temporary or permanent neurological deficit. CONCLUSION: The combined endovascular and surgical approach is feasible, without cross-clamping of the aorta and with minimized ischemia time for renal and visceral arteries, and seems the appropriate strategy for high risk and previously operated, with a thoracoabdominal trans-diaphragmatic approach, patients.

Aged↗

[Endoluminal stent-assisted management of acute traumatic aortic rupture].

INTRODUCTION: Open repair of traumatic descending aortic rupture in trauma patients is associated with a mortality rate of 15-20% and a risk of paraplegia of 5-10%. Stent grafts may decrease the morbidity and mortality of these procedures by reducing blood loss and aortic occlusion time. MATERIAL AND METHODS: Within an experience of 52 thoracic stent grafts between 1995 and 2000, eight men with acute traumatic descending aortic rupture were conducted as emergencies without delay. All patients had severe coinjuries and presented with acute onset of mediastinal hematoma due to periaortic bleeding. Successful stent deployment was performed in all eight patients, seven of them required one single stent and one required two stents; within the aortic arch all stents covered the origin of the left subclavian artery. RESULTS: All acute aortic ruptures were sealed successfully. One death occurred in hospital from multiorgan failure. There was no conversion to open repair. Not one patient's condition resulted in temporary or permanent paraplegia. One endoleak required treatment by overstenting. Two patients required secondary surgical procedures (iliac access complication and revascularisation of left subclavian artery). Mean follow-up was 11 months (1-21 months). Mid-term freedom from endoleak was monitored in all patients. CONCLUSION: The treatment of acute traumatic descending aortic rupture with an endovascular approach is feasible and safe and may offer the best means of therapy. The mortality rate and risk of paraplegia are low compared with the risks associated with open operations. Continued surveillance is essential.

Acute Disease↗

Endovascular repair of aortic rupture due to trauma and aneurysm.

OBJECTIVES: to report a single centre experience with endovascular repair of the ruptured descending thoracic and abdominal aorta. DESIGN: prospective non-randomised study in a university hospital. MATERIAL AND METHODS: between 1995 and 2000, endovascular treatment was utilised for 231 aortic repairs; in 37 cases (16%) endografting was conducted on an emergency basis for 21 ruptured infrarenal aortic aneurysms, 15 ruptured descending thoracic aortic lesions, and 1 ruptured thoracoabdominal aortic aneurysm. The feasibility of endovascular treatment and the prostheses' size were determined, based on preoperative spiral CT and intraoperative angiography, both obtained in each patient. RESULTS: endografting was successfully completed in 35 patients (95%). Primary conversion to open repair was necessary in 2 patients (5%). Postoperative 30-day mortality rate was 11% (4 deaths). No patient developed postoperative temporary or permanent paraplegia. In 2 patients (5%) primary endoleaks required overstenting and in 6 patients (16%) secondary surgical interventions were required. Mean follow-up was 19 months (1-70 months); three deaths occurred within three months postoperatively (1-year survival rate 81+/-6%). In one case, secondary conversion to open repair was necessary 14 months postoperatively. CONCLUSION: the feasibility of endoluminal repair of the ruptured aorta has been demonstrated. Endoluminal treatment may reduce morbidity and mortality, and may in time become the procedure of choice in certain centres. However, further follow-up is required to determine the long-term efficacy.

Adolescent↗

[Repeat rupture of covered rupture of non-anastomotic false aneurysm after femoropopliteal bypass].

For arterial reconstructions veins or alloplastic vascular prostheses are used. Nonanastomotic pseudoaneurysms of vascular protheses are a rare event. Breaks of the suture material, structural defects of the transplant fabric or degenerative modifications in the recipient vessel can cause nonanastomotic or anastomotic pseudoaneurysms. Such pseudoaneurysms are known from early clinical application of ePTFE grafts. In the case presented a nonanastomotic rupture of a ePTFE graft is described with partial repair of the rupture site by fibroblasts and connective tissue, which prevented bleeding.

Anastomosis, Surgical↗

Endoluminal grafting of infrarenal aortic aneurysms.

BACKGROUND: The department policy regarding therapy fo infrarenal aortic aneurysms is reviewed, based on the treatment results of a 12-months period. METHODS: From October 1996 to August 1997, 60 patients with infrarenal aortic aneurysms were admitted to our department. Of these 31 (52%) were found to be anatomically or pathomorphologically suitable for endovascular treatment, based on the premises that: 1. Whenever the anatomy is suitable and confirmed with CT or angiography, repair is by means of stent placement. 2. In emergencies and in cases where the anatomical relationships are unfavourable, patients undergo conventional open surgery. RESULTS: In all 31 patients treated endovascularly, stent placement was technically successful. Procedure-associated mortality was zero. The following stenting complications occurred: seven endoleaks, one thrombotic iliac occlusion, one femoral arterial dissection, two puncture-related inguinal hematomas. Elective open surgery was performed in the other 29 patients. One of these died from the effects of renal failure. CONCLUSIONS: This comparison shows that endovascular treatment of infrarenal aortic aneuryms is possible in a large proportion of patients and is not associated with an unfavourable rate of complications. Endovascular treatment can significantly reduce patients' postoperative hospitalization (three days) and time spent in intensive care.

Aged↗

Leakages after endovascular repair of aortic aneurysms: classification based on findings at CT, angiography, and radiography.

PURPOSE: To ascertain whether the configuration and location of leakages identified at computed tomography (CT) could provide evidence of their angiographically and fluoroscopically confirmed causes. MATERIALS AND METHODS: Fifty patients aged 26-79 years underwent endovascular repair of traumatic (n = 4) or arteriosclerotic (n = 46) aortic aneurysms (four thoracic, 46 infrarenal). Radiographic examinations in three planes and helical CT were performed 1 week after implantation and every 3 months thereafter. Angiography was performed when there was evidence of a leakage at CT. RESULTS: CT demonstrated evidence of leakages in 13 patients. Broad-based leakages immediately adjacent to the prosthesis were termed "perigraft leakages." If the area most affected by the leakage lay along the border of the aneurysm, then retrograde leakages were apparent at angiography. If the leakage was ventral to the prosthesis, then its source was the inferior mesenteric artery; if it was dorsolateral, then it was supplied by either the lumbar arteries or the median sacral artery through the hypogastric artery. One circumferential leakage could not be evaluated adequately at CT or angiography. Radiography depicted a rupture of the stent mesh in the middle of the prosthesis. Selective angiography demonstrated all types of leakages and permitted CT classification. CONCLUSION: The cause of a leakage can be determined with CT on the basis of its configuration and location in the majority of cases.

Adult↗

Endovascular repair of aortic aneurysms: treatment of complications.

PURPOSE: To evaluate the use of interventional procedures for treating complications following endovascular repair of aortic aneurysms. METHODS: Fifty-five patients (49 men; mean age 67.5 years) underwent endoluminal stent-graft repair of traumatic (n = 4) or arteriosclerotic (n = 51) aortic aneurysms in the thoracic (n = 3) or infrarenal (n = 52) aorta. Follow-up of therapeutic success included periodic clinical examination, angiography, and spiral computed tomography. RESULTS: Discounting the 25 (45%) cases of postimplantation syndrome that did not require treatment, there were 22 complications observed in 20 (36%) patients over a mean 10-month follow-up (range 1 to 27). There were 2 transrenal endograft maldeployments, 1 case of twisted graft limbs, 2 access site problems (1 patient), 12 endoleaks (11 patients), 1 late graft limb thrombosis, 1 symptomatic internal iliac artery occlusion, 2 myocardial infarctions, and 1 transient psychosis. Seven (13%) patients did not undergo specific therapy, while 4 (7%) required operation (2 crossover bypass grafts, 1 suture revision, and 1 graft replacement). Among 9 (16%) patients treated with interventional techniques, 7 underwent percutaneous coil embolization for 8 endoleaks (7 successfully resolved). One late stent-graft disconnection required an additional stent-graft, and 1 of the 2 malpositioned endografts was repositioned. All patients remain alive with no increase in the diameter of the aneurysm in any patient. CONCLUSIONS: Technical problems resulting from the endovascular repair of aortic aneurysms often respond to interventional treatment.

Adult↗

Ibuprofen does not impair renal function in patients undergoing infrarenal aortic surgery with epidural anaesthesia.

OBJECTIVE: To investigate the effect of preoperative ibuprofen administration on renal function during and after infrarenal aortic surgery under thoracolumbar epidural anaesthesia (EPA). DESIGN: A prospective randomised, double-blinded clinical study. SETTING: Operation room and intensive care unit in a university hospital. PATIENTS: Twenty-six consecutive patients scheduled for elective infrarenal aortic surgery. INTERVENTIONS: The patients were prospectively randomised to receive 400 mg ibuprofen intravenously (i.v.) or a placebo aliquot before surgery. MEASUREMENTS AND RESULTS: We assessed renal function by calculating creatinine clearance, and fractional sodium excretion before surgery (baseline), 1 h after cross-clamping (intraoperative), 6 h after cross-clamping (postoperative) and 24 h after cross-clamping (on the 1 st postoperative day). At each point in time, we additionally registered haemodynamics and determined the plasma concentration of 6-keto-PGF1alpha (stable metabolite of prostacyclin, PGI2), bicyclic PGE2 (stable metabolite of PGE1 E2), active renin, aldosterone and vasopressin by radioimmunoassays. Throughout the observation period the renal function parameters mostly remained within the normal range without a significant difference between ibuprofen- and placebo-treated patients (creatinine clearance: baseline 41 +/- 3 vs 38 +/- 6, intraoperative 57 +/- 8 vs 64 +/- 11, postoperative 64 +/- 9 vs 56 +/- 9, first postoperative day 43 +/- 5 vs 47 +/- 6 ml x min x m(-2), means +/- SEM). The plasma levels of 6-keto-PGF1alpha (68 +/- 8 vs 380 +/- 71* ng x l(-1)), bicyclic PGE2 (57 +/- 5 vs 88 +/- 9* ng x l(-1)) and vasopressin (14 +/- 7 vs 45 +/- 10* ng x l(-1), p < 0.0125), however, were significantly higher during the intraoperative period in the placebo-treated patients. CONCLUSION: The inhibition of endogenous prostaglandin release by ibuprofen does not substantially impair renal function during infrarenal aortic surgery under EPA.

Aged↗

Comparison of virtual and fiberoptic bronchoscopy.

Preoperative diagnostic procedures in the treatment of non-small-cell lung carcinoma (NSCLC) include fiberbronchoscopy (FBS) and CT scanning of the thorax and abdomen. The introduction of double-detector helical computed tomography has led to improved image resolution which allows three-dimensional reconstruction of the bronchial tree. A special computer simulation provides a virtual endoscopic view into the inner surface of the bronchial system. In order to determine whether the so-called virtual bronchoscopy (VBS) accurately reflects the anatomic situation of the bronchial tree, neoplastic lesion, and postoperative control of sleeve resections, we performed a virtual bronchoscopy in 24 patients with NSCLC and in 6 patients following sleeve resections and compared the results with the findings of fiberoptic bronchoscopy. An anatomic computer simulation of the bronchial tree was created in 100% of the investigated patients. Central tumor stenosis or occlusion was visualized by VBS as well as by FBS. In peripheral tumorous lesions VBS revealed the correct diagnosis in only 75%. VBS, however, enables viewing beyond the stenosis. FBS remains the gold standard in the endoscopic diagnostic procedures, showing not only airway patency but also mucosal changes in the vicinity of the tumorous lesion. VBS, however, gives further information about the poststenotic area in occlusive main bronchus stenosis. Furthermore, adequate control investigation of airway patency in patients following sleeve resections or stent implantation can be performed by VBS.

Bronchoscopy↗

Vasopressor hormone response following mesenteric traction during major abdominal surgery.

BACKGROUND: We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI2) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. METHODS: In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGF1 alpha (stabile metabolite of PGI2), TXB2 (stabile metabolite of thromboxane A2) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. RESULTS: Following MT, arterial hypotension occurred along with a substantial PGI2 release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF1 alpha (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P = 0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB2 (164 (87) vs. 58 (1) ng/L, P = 0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P = 0.001), AVP (41 +/- (18) vs. 12 (7) ng/L, P = 0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. CONCLUSION: Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI2 release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A2, presumably contributing to hemodynamic stability within 30 min after MT.

Abdomen↗

Diagnostic value of spiral-CT angiography in comparison with digital subtraction angiography before and after peripheral vascular intervention.

To evaluate spiral-computed tomography (CT) angiography in primary diagnosis and/or in noninvasive follow-up after vascular intervention, we compared spiral-CT angiography and conventional angiography before and after vascular intervention. Helical-CT examinations before and after percutaneous transluminal angioplasty (PTA) or stent implantation were performed in 10 patients (mean age 63 years) with symptomatic peripheral arteriosclerotic disease. Stenoses were located in the iliac, femoral, or popliteal artery. CT examinations were done with a spiral-CT in double detector technique (CT Twin, Elscint). The parameters were as follows: slice thickness: 5.5 mm, increment: 2.7 mm, pitch: 1.5, contrast medium: 150 mL, flow rate: 2.5 mL/second, delay: 30 seconds. For evaluation, transverse planes as well as maximum intensity projections and 3-D reconstructions were used. The possible scan length reached from the aortic bifurcation down to about 10 cm below the ankle trifurcation. Preinterventional digital subtraction angiography (DSA) was superior to CT angiography (CTA: 94%, maximum intensity projection [MIP] alone: 65%), although high-grade stenoses were detected by both methods. After intervention, a resolved stenosis and improved peripheral flow could be detected by helical-CT as well as by intraarterial angiography in every patient (100%). In the primary diagnosis of vascular changes, intraarterial DSA remains the method of choice. Nevertheless, spiral-CT angiography shows comparable results after percutaneous intervention and becomes a noninvasive alternative in the postinterventional follow-up.

Angiography↗

Emergent endoluminal repair of delayed abdominal aortic rupture after blunt trauma.

PURPOSE: To report the emergency repair of a traumatic abdominal aortic rupture using endoluminal techniques. METHODS AND RESULTS: A 25-year-old female sustained multiple head, chest, and abdominal injuries in a motorcycle accident. Six days after emergency treatment (including splenectomy and repair of a superficial hepatic rupture and lacerations to the stomach, small bowel, and colon), she became hemodynamically unstable. A massive retroperitoneal hematoma had evolved from a distal aortic rupture. Owing to a hostile abdomen and possibility of bacterial contamination, a self-expanding stent-graft was inserted transfemorally to repair the aortic injury. The patient recovered uneventfully and continues in good health with a patent endograft repair 2 years after treatment. CONCLUSIONS: This experience would support the efficacy of endograft implantation for emergent repair of trauma aortic injuries; however, proper facilities, an experienced interventional team, and an assortment of endografts and stents must be available.

Adult↗