Biomedical subjects

H Dedichen

Publications and source records attributed to H Dedichen.

At least 19 recordsLinked to original sources

PubMed1995

Collagen-induced thrombus formation in flowing nonanticoagulated human blood from habitual smokers and nonsmoking patients with severe peripheral atherosclerotic disease.

The objective of the present study was to investigate collagen-induced platelet thrombus formation at arterial blood flow conditions in nonanticoagulated blood from habitual smokers and from nonsmoking patients with severe peripheral atherosclerotic disease. Collagen-induced thrombogenesis was elicited in native blood drawn directly from an antecubital vein over immobilized type III collagen fibrils coated on a coverslip positioned in a parallel-plate perfusion chamber. The wall shear rates at the collagen surface were comparable to those encountered in medium-sized (650 s-1) and moderately stenosed (2600 s-1) arteries. Thrombus formation in blood from habitual smokers after 10 hours of smoking abstinence appeared to be not different from thrombus formation in blood from healthy nonsmokers. However, immediately after a cigarette had been smoked, thrombus volume in blood from the same individuals was increased twofold at the highest shear rate (P < .05). Thus, the thrombotic response was temporarily upregulated after smoking. Thrombus formation in blood from nonsmoking patients with severe peripheral atherosclerotic disease was neither enhanced nor decreased but was within the range of the nonsmoking control subjects. However, fibrinopeptide A generation after 4 minutes of perfusion at 2600 s-1 was higher in blood from the atherosclerotic patients (P < .05) and associated with a higher plasma fibrinogen level (P < .005). Thus, signs of changed platelet reactivity in flowing nonanticoagulated blood were encountered only in the habitual smokers immediately after they had smoked a cigarette.

Adult↗

PubMed1994

[Aortoiliac arteriosclerosis treated with bypass surgery].

After introduction of the crimped Dacron bifurcation prosthesis, bypass surgery has been the preferred surgical treatment for arteriosclerosis in the aortoiliacal segment. During the years 1979-88 we performed 152 aortoiliacal/femoral bypass operations. Perioperative mortality was 2%, while 96% of patients experienced improvement from operation. Primary and secondary five-year graft patency rates were 84 and 88%. Considering the high risk in this patient group, we regard the operational mortality to be acceptable, and the long term results satisfactory. However, surgical treatment should be reserved for patients with serious occlusive disease in the aortoiliac segment. For patients with more limited lesions, endovascular procedures are a relevant alternative to surgery.

Adult↗

PubMed1994

[Femoropopliteal bypass in arteriosclerosis].

Since Kunlin's report on femoropopliteal bypass operations, this procedure, with homologous vein or various prosthesis has been the principal treatment for serious arteriosclerosis in this anatomical area. During the years 1979-88 we performed 235 femoropopliteal bypasses. Reversed autologous vein was used in 60% and the distal anastomosis placed below the knee in 75%. Perioperative, 30 days mortality was 2.1%. 93% of the operations were successful. The overall five year patency rate was 50.6%, but with significantly better results with the distal anastomosis above the knee. There was no significant difference, however, between reversed homologous vein and human umbilical vein grafts in the below knee position. At present, the indications for femoropopliteal bypass are critical ischemia and seriously incapacitating claudication.

Adult↗

PubMed1994

[Percutaneous transluminal angioplasty in the treatment of arteriosclerosis of the lower extremities].

With the introduction of balloon catheters in 1974, dilatation of arteriosclerotic stenoses has become an important treatment for this condition. During the years 1979-88, 368 such procedures were performed in 270 patients. Two patients (0.7%) died from complications. In 8%, revascularisation was unsuccessful. Long occlusions appeared especially difficult to recanalize. 81% of the patients were improved by the treatment. The long term results were best in the iliac segment with 5-year patency of 90% after dilatation of short stenoses (< 4 cm) and 65% after dilatation of longer stenoses. In the femoropopliteal segment, the 5-year patency rates were 65% and 50% respectively. Results after recanalisation of occlusions were poor. Percutaneous transluminal angioplasty is an important supplement to surgery, applying mainly to patients with limited arteriosclerosis and moderate symptoms.

Adult↗

PubMed1994

[Percutaneous transluminal angioplasty with stent in arteries of the lower extremity].

The application of intraluminal stents after dilatation of arterial stenoses and occlusions has proved to be a valuable addition to the armamentarium of radiological interventions. During the last two years we have applied 70 stents to 59 arterial lesions of the lower extremities in 45 patients. 57, or 96.6%, of the procedures were primarily successful, while two patients needed bypass surgery within 1-3 weeks. Follow up at 3-24 months showed that two stents were occluded 12-18 months after insertion, while intravenous digital substraction angiography showed the rest to be still open. We conclude that intravascular stenting improves the overall results of percutaneous transluminal angioplasty, and consequently expands the indications for this therapeutic procedure.

Aged↗

PubMed1993

[Autologous vein vs. human umbilical vein for femoropopliteal bypass].

Below knee femoropopliteal bypass was performed with reversed saphenous vein in 81 cases and with modified human umbilical vein in 74. The two groups were comparable as regards indications, coexisting disease and distal run-off. The cumulated patency rates were almost identical in the two groups, but early mortality and wound complications were higher in the saphenous vein group. Aneurysm formation in the umbilical veins was not a problem in this series. It is concluded that human umbilical vein is a very satisfactory bypass alternative when the saphenous vein is not available. In selected cases it may also be justifiable to use it in order to keep operation time and trauma at a minimum.

Adult↗

PubMed1992

[Vascular injuries of the extremities].

The diagnosis of vascular injuries may be delayed because the symptoms are masked by other injuries or may develop gradually after the first examination took place. If serious ischemic damage is to be avoided, a high degree of diagnostic alertness is necessary, and angiography should be performed whenever vascular injuries are suspected. Most vascular injuries can be repaired by simple techniques: In our experience the most frequently used reconstruction techniques were direct suture of the artery or a longitudinal arteriotomy with thrombendarterectomy and patch plasty. In complicated injuries with much destruction of tissue, the best solution may be an extra-anatomic bypass with a prosthetic graft. Simultaneous venous injuries should be repaired and fasciotomies performed on liberal indications. Pseudoaneurysms and arteriovenous fistulae should be diagnosed and treated early.

Angiography↗

PubMed1989

[Aneurysm of the leg].

During the years 1967-87, 19 patients, all men, have been operated on for 26 aneurysms in the femoropopliteal area. Bi-lateral aneurysms were seen in 10 patients and 14 patients had aneurysms at several levels. 14 aneurysms were operated on as vascular emergencies. There was no perioperative mortality. Six grafts implanted for repair of popliteal aneurysms occluded. Two patients had a major amputation because of complications following acute surgical intervention. As a general rule periferal aneurysms should be treated operatively because they represent a threat to the limb by embolism, thrombosis and rupture.

Aged↗

PubMed1989

[Arterial injuries].

During the years 1963-87, 57 patients were treated for arterial injuries. Iatrogenic injuries are excluded. 60% were due to accidents and only 12% to interpersonal violence. Three patients died from the injuries, eight extremities required a primary amputation, eight patients got sequela related to orthopedic problems or ischemia, and 35 patients achieved complete restitution of function. 53% of the injuries were due to fractures, dislocations or contusions while 21% were caused by penetrating lesions. The most common lesion was an intimal rupture with dissection and thrombosis in an otherwise intact vessel (40%). The most frequently applied technique of reconstruction was longitudinal arteriotomy with thrombendarterectomy and patch plasty. Other arteries were repaired by direct suture, interposition of a suitable graft or by a bypass. Fasciotomies were based on liberal indications. A high degree of diagnostic alertness is necessary if irreparable ischemic damage is to be avoided.

Accidents↗

PubMed1989

[Late sequelae after arterial injuries].

Of 57 patients with arterial injuries, three died, eight had an amputation and 14 experienced various kinds of late sequelae. Four of the sequelae were due to inadequate primary surgical treatment: 1) A 16 year-old girl developed incapacitating claudicatio intermittens after a traffic accident causing serious contusions to the right leg. Angiography four years later showed occlusion of the popliteal artery, which was successfully reconstructed. 2) A 16 year-old boy had a femoral fracture with injuries to the femoral artery and vein. The vessels were reconstructed and circulation was restored, but fasciotomies were not performed. He developed a flexion contracture of the 1st toe which required resection of the proximal phalanx. This was interpreted as a Volkmanns contracture due to a compartment syndrome in the deep, posterior compartment of the leg. 3) A 18 year-old man had a fracture of the leg. Angiography demonstrated a minimal leak from the posterior tibial artery, but this was not surgically explored. Six weeks later a pseudoaneurysm ruptured and produced a large hematoma. Circulation was restored by arteriotomy and a patch plasty. 4) A 24 year-old man was hit in the groin by a 22 caliber rifleshot. An arteriovenous fistula was diagnosed but not surgically treated. Six years later he experienced cardiac failure and venous insufficiency. The fistula was closed, whereafter the symptoms disappeared. Blood flow in the fistula was 7,500 ml/min and the pressure in the distal femoral vein 37 mm Hg. These complications can be avoided by proper investigation and surgery at the time of initial treatment.

Adolescent↗

PubMed1989

Hemodynamics and blood flow distribution in experimental shock. The effect of noradrenaline and isoproterenol.

Cardiac output, regional blood flow and other hemodynamic variables were observed on dogs in hemorrhagic and in endotoxin shock. In hemorrhagic shock, a redistribution of cardiac output from other vascular beds to the coronary circulation was seen. This was induced by vasoconstriction in all vascular regions except the coronary arteries. In endotoxin shock, vascular resistance increased in some regions and decreased in others. A redistribution in favor of the mesenteric and femoral regions was seen. The coronary circulation was relatively well maintained in either shock models. Increased oxygen extraction was seen in all vascular beds. Blood pH was decreased corresponding to the degree and duration of the shock. Only small regional variations were observed in these variables. Noradrenaline increases vascular resistance in all regions except the coronary arteries. Isoproterenol reduces vascular resistance in all areas. Both drugs have cardiotropic effects. The same response was seen in normal as well as in shocked dogs. In addition to principal shock treatment, there may still be a place for the judicious use of these drugs in shock therapy.

Animals↗

PubMed1988