Semi-closed femoropopliteal thromboendarterectomy: a prospective study.

OBJECTIVE: to study the primary patency rates of angioscopically controlled thromboendarterectomies of the superficial femoral artery. DESIGN: prospective open study. METHODS: between 1990 and 1995, femoropopliteal thromboendarterectomies were performed in 63 patients (41 male, 22 female). Postoperative follow up was performed at 3- to 6-month intervals using non-invasive pressure measurements plus IVDSA at 1 year. RESULTS: eight patients were not evaluable, leaving 55 patients eligible for follow-up analysis. Postoperative complications (arteriovenous fistulas, false aneurysms) were observed in 5.4% of patients. Immediate perioperative occlusions occurred in 7.3%, early occlusions in 21.8% and late occlusions in 16.4% of all cases. The mean follow-up was approximately 57 months. The mean primary patency rate at 5 years was 44.5% (28 patients with the superficial femoral artery still open). Six patients died during the follow-up period. CONCLUSIONS: in contrast to the very positive reports found in recent literature, this prospective study shows a lower five-year patency rate for semi-closed femoropopliteal thromboendarterectomy than for bypass grafting. Thromboendarterectomy cannot be considered as a standard procedure in revascularisation of the femoropopliteal region.

[High-degree bilateral carotid stenoses]. / Hochgradige bilaterale Karotis-Stenosen.

The indication for carotid endarterectomy in patients with unilateral stenotic lesions as well as the operative risk in patients with bilateral disease is still controversial among experts. We performed a retrospective analysis in our patients with bilateral carotid endarterectomy. 578 patients underwent carotid endarterectomy at our institution from 1986-1992: 54 patients (9.3%) had bilateral carotid disease. 30% of these patients were asymptomatic and 16% had symptoms from both sides. Surgical results concerning the optimal restoration of blood supply (75%) and the occurrence of recurrent stenosis (8%) were comparable for patients with unilateral and bilateral carotid endarterectomy. On the contrary, in patients with bilateral carotid disease, both the operative morbidity (2.8%) and mortality (1.8%) were increased as compared to the total study population (1.9% and 0.45% resp.). Carotid endarterectomy is very effective in preventing stroke especially in patients with multiple vessel disease as compared to the natural history of these lesions.

The morphology of the inferior epigastric artery has implications on its use as a conduit for myocardial revascularization.

The inferior epigastric artery (IEA) is a new arterial graft for myocardial revascularization. We examined the inferior epigastric artery, the internal thoracic artery (ITA) and representative sections of the coronary arteries in 45 postmortem examinations, for microscopic signs of atherosclerosis. In addition, a morphometric evaluation of the intima and media of both conduits was performed. The intima of the ITA is significantly thicker, but atherosclerosis is absent. There are fewer fenestrations/mm in the internal elastic lamina (IEL) (4.00 +/- 1.60 versus 4.62 +/- 1.46) of the IEA and the combined thickness of media and intima is lower (0.20 +/- 0.04 mm versus 0.30 +/- 0.06 mm). However, 24% of IEAs showed medial calcification of variable degrees. We conclude that the IEA should not be used routinely for myocardial revascularization until the long-term patency of this graft has been explored.

[Ablation of venous valves with Nd-Yag laser--an alternative to conventional valvulotomy?]. / Venenklappenablatio mit Nd-Yag Laser--eine Alternative zur konventionellen Valvulotomie?

The careful removal of venous valves during in situ venous bypass procedures is a problem that has not been completely solved. In this experimental study, valve ablation with the Nd-Yag laser was compared with conventional valvulotomy. The investigation was performed in vitro using human vein segments with a length of 20 cm. Conventional valvulotomy was performed 16 times, 20 valves were removed with a 400 mu-fibre and 26 with the hot tip. The results were evaluated by endoscopy, light and electron microscopy. There were no vein perforations with the valvulotome and the hot tip. Endothelial damage was documented in 85% with the valvulotome and was reduced significantly to 58% with the 400 mu-fibre. With the hot tip endothelial lesions were seen in only 30%. Valve remnants were always present with the valvulotome and in no more than 15% with the hot tip. Electron microscopy supported these results in general. There was no endothelial damage in 69%.

[Orthotopic arteriovenous fistula in dialysis patients: a special application of fluid dynamic processes]. / Die orthotopen arteriovenösen Fisteln beim Dialysepatienten: eine Sonderstellung fluiddynamischer Problematik.

Our experiments describe the flow patterns in translucent models of AV fistulas. The elasticity of the models is similar to human vessels walls. Dying of particular flow threads with methylene blue visualizes the flow and its disturbances in 4 classical models. The flow dynamics were investigated with parallel inflow. The volume flow was constant at 200 and 400 ml/min, with a volume flow ratio of 80:20. The flow pattern in side to side fistulas and in end to side fistulas with a narrow angle show regions of separation. This may lead to microthrombus formation and early failure. High shear stress causes endothelial lesions and thus induces stenosing intimal reactions. A favourable flow pattern was seen in end to side fistulas with a broad angle, as well as in end to end fistulas.

Severe bilateral carotid stenosis.

An analysis of the relevant data from the Veterans Affairs Cooperative Study Group in asymptomatic patients, showed that 26 of the 32 ipsilateral strokes occurred during the first two years of clinical follow-up. Furthermore, as observed in the medical group, half the neurologic outcome events were strokes and were not preceded by transient ischemic attacks. In the North American Symptomatic Carotid Endarterectomy Trial over a 2-year period, 45 percent of those with occlusion had a stroke compared to 15 percent in the surgical group. These data dispel the traditionally held view that patients with severe contralateral disease should not be subjected to surgery. However, the referral of patients to centers capable of low rates of surgical complications is essential in a plan that includes carotid endarterectomy with optimal medical management.

Angioscope-guided neodymium yttrium-aluminium-garnet laser valvulotomy for in situ vein bypass.

Valvulotomy for in situ vein bypass is commonly performed with a valvulotome. Although the procedure can be controlled through an angioscope, the dangers of intimal damage and valve remnants remain. An experimental study was designed to evaluate angioscopic laser valvulotomy compared with standard mechanical valvulotomy (n = 16). Two different laser probes, a bare 400-microns fibre (n = 20) and a 2-mm hot-tip (n = 26) were tested. Results were investigated by histology and scanning electron microscopy. Hot-tip laser valvulotomy achieved significantly better results than the 400-microns fibre. The Insitucat valvulotome yielded the worst results, with valve remnants in all cases and an 88 per cent rate of intimal damage. It is concluded that laser valvulotomy can be performed simply and safely with a very low incidence of valve remnants and intimal damage.

[Results of vascular surgery treatment of vertebrobasilar insufficiency]. / Ergebnisse gefässchirurgischer Therapie bei vertebrobasilärer Insuffizienz.

A retrospective analysis of the data of 64 patients with vertebral-basilar insufficiency is presented who were operated between 1980 to 1919 in our institution. Surgery for vertebral-basilar insufficiency comprises only 5.2% of all 1422 supra-aortic reconstructions performed during this period. The leading symptom was vertigo which was present in 41%. Disturbances of vision occurred in 9.8%. 29 bypass procedures and 35 arterial transpositions were performed. A mean follow up of 5.1 years revealed a patency rate of 83.3% in bypass procedures, 92.8% in subclavian transpositions and 100% in vertebral artery transpositions. These good haemodynamic results correlated with marked improvement of the clinical symptoms in 80% of the patients.

Coagulation in aortofemoral bifurcation bypass grafting.

Few data are available on the pathophysiology of the coagulation system during aortic surgery. Cross-clamping of the aorta, intestinal eventeration and circulatory shock in ruptured aortic aneurysms are thought to cause coagulation disturbances and hyperfibrinolysis. A prospective study of several parameters of the clotting system, i.e. standard clotting tests, platelet count, indicators of fibrinolysis, inhibitors of the clotting cascade and proteases were measured perioperatively in aortobifemoral bypass grafts. Ten patients undergoing elective procedures and two emergency cases with ruptured aortic aneurysms were included. The standard clotting tests reflected the use of heparin. A similar course of ATIII, C1-inhibitor, alpha 2-antiplasmin, plasminogen and fibrinogen with a decrease during the operation and a return to almost normal values postoperatively, were due to intra-operative blood loss, haemodilution and a slight activation of the clotting cascade, as well as, hyperfibrinolysis. This observation was supported by the increased levels of euglobulin lysis and PMN-elastase and the resultant increase in some fibrinogen degradation products, indicating non-specific proteolysis. These changes were more pronounced in the two emergency cases, except for the heparin induced changes in PTT and thrombin time. It is concluded that non-specific proteolysis may be an important factor in the pathogenesis of clotting disorders in surgery of the aorta. Further research is needed to discover the pathways of non-specific proteolysis and its prevention by protease inhibitors.

[Crural bypass as reoperation]. / Der crurale Bypass als Rezidivoperation.

A retrospective study of 93 patients who have had repeat surgery at the tibial level for critical limb ischemia was carried out. In 21 patients a pseudoocclusion with a patent bypass graft was diagnosed and treated by PTA, thrombendarterectomy, or distal extension of the graft. The 5-year bypass patency was 60%, compared to 38% in those 72 patients that required a new bypass at the tibial level. Vein bypasses were better than prosthetic grafts. The number of previous operations did not negatively influence the outcome. However, the distal anastomosis should be placed on an artery that was not previously thrombectomized or operated on.

[Measuring regional blood flow in evaluating CT-controlled lumbar sympathetic neurolysis in arterial occlusive disease]. / Durchblutungsmessungen zur Wertigkeit der CT-gesteuerten lumbalen Sympathikolyse bei arterieller Verschlusskrankheit.

A prospective study was designed to evaluate the effect of CT-guided lumbar sympathectomy in PAOD using the following investigations: 1: laser flowmetry, 2. thermography, 3. plethysmography, 4. thallium scintigraphy. A significant improvement of perfusion was shown. The results of thallium scintigraphy disproved the often claimed steal effect of the muscle perfusion in favor of an increased skin perfusion. 80% of the treated patients experienced relief of their pain. Chemical sympathectomy proved to be as effective as the surgical procedure.

[Electronic data processing data bank for vascular surgery as a multiple site system with network connection]. / EDV-Datenbank für Gefässchirurgie als Mehrplatzsystem im Netzverbund.

A clinical database, using FileMaker Pro and a network of APPLE Macintosh computers, were created for a vascular surgical unit. The databank presented here is based on proven, routine working procedures of the department. An easily learnable entry facility with hands-on, screen-oriented users' guide and help data file provide easy operability and highly efficient databank capability, along with great flexibility. This criterial and user-friendly features make staff acceptance and compliance readily achievable, thus assuring comprehensive data entry.

[Coagulation changes during aortofemoral bifurcation bypass: is volume and plasma substitution possible with hydroxyethyl starch alone?]. / Gerinnungsveränderungen bei aortofemoralem Bifurkationsbypass: ist eine Volumen- und Plasmasubstitution mit Hydroxyäthylstärke allein möglich?

The study explored the possibility of eliminating the need for plasma replacement with expensive human albumin (HA) and fresh frozen plasma (FFP) and instead using hydroxyethyl starch (HES). Patients undergoing infrarenal aortofemoral bifurcation grafting were randomly assigned to one group, which received FFP and HA, or another group, which received HES as volume replacement. Blood specimens were collected at five time intervals: preoperatively, prior to cross-clamping of the aorta, prior to declamping, at the end of the operation, and 6 h postoperatively. Preoperative coagulation values were all within normal limits. The basic coagulation tests were generally affected by the standardized heparin dose of 5000 IU administered during the clamping phase. Euglobulin lysis demonstrated a perioperative climb that was particularly marked within the HES group at the time of clamping. Values returned to initial levels 6 h postoperatively. Plasminogen, fibrinogen, antithrombin III, and antiplasmin concentrations fell significantly in both groups; 10% to 20% lower values were determined within the HES group due to the lack of factor substitution. The reduction in the coagulation factors can be explained as a dilution effect, but there are also signs of a consumption reaction taking place at the onset of the operation involving activation of coagulation and fibrinolysis. Restricting the use of FFP and simultaneously increasing HES administration is justifiable in procedures involving the abdominal aorta with moderate blood loss.

Ileocolectomy enhances the regenerative response after partial hepatectomy in the pig.

Although portal blood has been shown to be more hepatotrophic than peripheral venous blood, the origin and nature of the factors responsible remain obscure. In this study the effect of partial ileocolectomy (IC) or partial ileal resection (I) on the regenerative response after 50% partial hepatectomy (PH) in the pig was investigated using thymidine kinase activity and mitotic figures as indices of regeneration. IC with 50% partial hepatectomy resulted in a significantly greater regenerative response on the 3rd day than hepatectomy alone or hepatectomy plus partial I. Levels of plasma insulin were elevated after PH and I but not after IC, although there were no significant differences in levels of plasma glucagon or plasma glucose. Levels of aspartate amino-transferase were similar in all groups. These results extend previous data and suggest that the proximal colon may be the source of a regeneration inhibitory factor.

[What are the prerequisites for surgery of asymptomatic carotid stenosis?]. / Unter welchen Voraussetzungen dürfen wir asymptomatische Carotisstenosen operieren?

Asymptomatic patients with carotid stenoses exceeding 75% have an elevated ischemic cerebrovascular event rate of 18% per year (5% strokes). Our combined perioperative stroke and death rate (1980-1990: 1123 operations) is 1.85%. Thus prophylactic surgery may be indicated in the following cases: hemodynamically significant stenoses of 75% and more, especially with marginal or reduced autoregulatory reserve, rapidly progressing lesions in medically treated patients, lesions with a high risk of embolization (ulcerations on B-scan), clear interrelation between arterial lesions and positive (asymptomatic) intracranial findings (CT, NMR, TC, USD).

[Subtotal and total traumatic extremity amputation--when replantation, when amputation?]. / Subtotale und totale traumatische Gliessmassenabtrennung--wann Replantation, wann Amputation?

The major problems besetting replantation of a limb are the very limited tolerance of muscle tissue to ischemia (in our experiences 5 h) and the possibility of severe postischemic complications either in the limb itself (capillary thrombosis, muscle necrosis) or systemically (kidney failure, speticemia). Between 1975 and 1988, 66 limb replantations (57 arms, 9 legs) were carried out. All nine legs had to be reamputated. Forty-five of the 57 reattached upper extremities (80%) healed without any major complications, 60% exhibited good or very good results (Grade II or I, Classification by Chen).