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Biomedical subjects

S Amundsen

Publications and source records attributed to S Amundsen.

11 recordsLinked to original sources

Endovascular treatment of abdominal aortic aneurysms in Norway: the first 100 patients.

OBJECTIVES: to present the first 100 consecutive endograft implantations for abdominal aortic aneurysms (AAAs) in Norway. DESIGN: retrospective study of 100 consecutive graft implantations, performed at five University Hospitals during 1995 to 1997. MATERIAL: one hundred patients with a median age of 70 years were included. In all patients the Vanguard modular system (Boston Scientific Corp.) was used. Ninety-four of the 100 patients were treated under regional anaesthesia. A completion angiography was done to evaluate the position of the graft and whether endoleaks were present. RESULTS: two patients died within 30 days, one due to cardiac insufficiency and another due to haemorrhage during the procedure. There were four early conversions to open repair. At discharge eight patients had an endoleak, while retrograde flow into the aneurysmal sac was observed in four patients. During the follow-up period one conversion to open repair became necessary due to graft migration. Four late leaks were all repaired successfully using endovascular techniques. Five cases of retrograde filling were detected and embolisation with coils was performed in two cases, while three were observed. Seven graft-limb occlusions occurred during the follow-up period and four of these required treatment. CONCLUSIONS: endovascular AAA repair should be regarded as an experimental treatment, although the short term results are promising. Close follow-up of patients with CT scans or arteriography is necessary.

Aged↗

[Hepatic artery aneurysm. Diagnosis and treatment].

From 1990 until 1995, four patients were successfully treated for symptomatic aneurysm of the hepatic artery, with rupture in three of them. In two of the patients, the aneurysm was located in the common hepatic artery. In one patient it ruptured. Both aneurysms were resected. One patient also underwent vascular reconstruction. The other two aneurysms ruptured in the left and right hepatic artery respectively. The aneurysm in the right hepatic artery was treated by selective embolization. The aneurysm in the left hepatic artery was ligated, and the patient was subsequently reoperated on for septic necrosis of the left lobe of the liver.

Adult↗

Total revascularization with T grafts.

The T graft is constructed by anastomosing the proximal end of the free right internal thoracic artery to the side of the attached left internal thoracic artery. Besides adding considerable reach to the right internal thoracic artery, this technique allows the left anterior descending coronary artery and its branches to be bypassed with the attached left internal thoracic artery. Two hundred eight-seven patients, aged 34 to 86 years (mean age, 64.6 years) received an average of 4.4 internal thoracic artery to coronary artery anastomoses. Sixty-nine patients had left main disease, 33 were undergoing first-time reoperations, and two were reoperated on for the second time. Ejection fraction ranged from 0.20 to 0.70. Operative mortality was 1.7%. Twenty-six patients had postoperative graft visualization, and 94.7% of the grafts were open. All 45 bypass grafts from the left internal thoracic artery were patent, and 91% of those from the right internal thoracic artery were unobstructed. This procedure requires technical skill with internal thoracic arteries, but it has the potential of significantly improving long-term event-free survival and reducing the need for reoperation in patients undergoing coronary artery bypass grafting.

Adult↗

T-graft: a new method of coronary arterial revascularization.

We present early results in 486 patients undergoing total coronary artery revascularization using a T-graft constructed from the attached left internal thoracic artery (LITA) and the free right internal thoracic artery (RITA). The anterior and anterolateral areas of the heart are by-passed with the LITA and the inferolateral, inferior and posterior areas are by-passed with the RITA. These patients received an average of 4.34 distal anastomoses with as many as four from each of the limbs of the T-graft. Ages ranged from 29 to 89 years and ejection fractions from 15 to 79%. Sixty-six patients were undergoing first reoperations and 6 received T-grafts at their second reoperation. The mortality at 30 days was 2.3%. Two of 92 women and 9 of 394 men expired. The perioperative infarction rate was 1.2%. Postoperative angiography in 34 patients showed 98.3% of LITA and 86.5% of RITA anastomoses to be patent. There was a slightly higher patency observed in women. The T-graft technique can be applied to nearly all patients with 3 vessel coronary artery disease with low operative mortality. Precise technique with high power magnification is crucial. This procedure has the potential of avoiding further invasive procedures due to graft deterioration in many patients with 3 vessel coronary artery disease.

Adult↗

Abdominal aortic aneurysms. Is there an association between surgical volume, surgical experience, hospital type and operative mortality? Members of the Norwegian Abdominal Aortic Aneurysm Trial.

The effects of number of operations, experience of the surgeon, and type of hospital on operative mortality have been studied in 444 patients treated for abdominal aortic aneurysms. In the elective group (n = 279) there was a significant difference in mortality between hospitals in which more than 10 such operations were done compared with those in which less than 10 were done during the study period (p = 0.05; odds ratio (OR) 2.7). In the ruptured group there was no statistically significant difference (p = 0.14; OR 1.9). In the elective group, units with vascular surgical experience had an operative mortality of 4.8% compared with 11.3% for other units (p = 0.05; OR 2.6). In the ruptured group the figures were 52.5% and 73.3% respectively (p = 0.03; OR 2.5). There was no difference in operative mortality between university, county and local hospitals. Outcome of treatment after operations for abdominal aortic aneurysm was related to number of operations carried out and experience, whereas the type of hospital seemed less important.

Aged↗

Abdominal aortic aneurysms--a study of factors influencing postoperative mortality. Norwegian Aortic Aneurysm Trial.

Factors which influenced outcome after surgery have been studied in 444 patients with abdominal aortic aneurysm included in a Norwegian multicentre study. Two-hundred and seventy-nine patients were treated electively, 51 had impending rupture and 114 had a ruptured aneurysm. In the elective group age, a large aneurysm, impaired renal function, the presence of angina pectoris and intraoperative blood loss of more than 4 units were found to significantly increase hospital mortality. In the impending rupture group excess blood loss during the operation had a negative influence on hospital death but the limited number of patients in this group restricts the value of analysis. A low systolic blood pressure and an older patient were the only 2 risk factors which had a detrimental effect on postoperative survival in the ruptured group. The formulation of a risk index for these patients was not possible although Odds ratios for the individual factors found to be of importance may give some risk estimates.

Aged↗

Abdominal aortic aneurysms--a national multicentre study.

A prospective, observational, multicentre study has been carried out on 444 consecutive patients with abdominal aortic aneurysms to study the effect of the diffusion of vascular service on treatment results. Two-hundred and seventy-nine patients were admitted for elective surgery (E), 114 patients had a ruptured aneurysm (R), and 51 had impending rupture (IR). Patients with acute symptoms (R + IR) were generally older and had larger aneurysms than the E group. The postoperative mortality was 7.5%, 16.7%, and 63.1% in the E, IR and R group respectively. The study demonstrates that overall treatment results in these high risk patients are inferior to results published from specialised institutions. Consequently, the diffusion of vascular surgical service seems not to have worked to the benefit of our patients although further analysis may modify this conclusion.

Aged↗

Microsphere method in measurement of blood flow to wall layers of small intestine.

Microspheres of 10.90 +/- 0.65 micron (SD) were injected in the superior mesenteric artery of cats and their intramural distribution and diameter in the small intestine were studied microscopically under basal conditions and after vasodilation by isoproterenol. Approximately 2% of the spheres were shunted through the small intestinal vasculature and could be recovered in the liver. Analysis of the tissue distribution suggested that all spheres arrested in villi represented villous blood flow, spheres arrested in the crypt layer represented flow to the crypts, and the majority of microspheres trapped in the submucosa also represented crypt flow. Nutritive blood flow to the submucosa constituted only 1.5% of total intestinal flow. Log-linear analyses identified factors responsible for sphere distribution, including effects of sphere size, isoproterenol treatment, and local blood flow or vascular resistance. Spheres with diameters greater than 11.08 micron had 1.35 times larger odds than smaller spheres to embolize in the muscularis rather than in the mucosa, but no consistent difference between diameter profiles in the crypts and villi was found. With this reservation, 11-micron spheres seem to be appropriate for measuring blood flow to the muscle, crypt, and villous layers of the small intestine.

Animals↗

Blood flow through vasa vasorum in arteries and veins: effects of luminal PO2.

We have examined effects of chronic reduction of intraluminal PO2 on blood flow through vasa vasorum, by comparing large arteries and veins, and effects of acute hypoxia on flow through vasa. Microspheres were used to measure flow in anesthetized dogs. Values obtained with different sizes of microspheres suggest that spheres 9 and 15 micron in diam, but not 50 micron, are appropriate for measurement of blood flow through vasa vasorum. Flow [expressed as ml X min-1 X 100 g-1 (SE)] through medial vasa was similar in the aorta (9.0 +/- 2.1) and pulmonary artery (9.3 +/- 1.1) although, on the basis of wall thickness and number of lamellae, one would predict much higher levels of flow to aortic media. Two veins that we studied have a thick muscular wall. Both veins had high levels of flow through medial vasa: 33 +/- 4.4 to the subdiaphragmatic inferior vena cava and 18 +/- 5.4 to the portal vein. Two other veins are apparently conduit vessels, with dense connective tissue and minimal smooth muscle. Both veins had minimal flow through medial vasa: 2.4 +/- 1.0 to superior vena cava, and 1.9 +/- 0.8 to supradiaphragmatic inferior vena cava. Thus, because flow through vasa differs greatly in different veins, structure of the vessel (as well as intraluminal PO2) is an important determinant of flow through vasa. Acute hypoxia increased conductance of medial vasa vasorum of arteries and veins when neurohumoral constrictor effects were blocked by phenoxybenzamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗