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Biomedical subjects

G Riepe

Publications and source records attributed to G Riepe.

26 records · Page 2Linked to original sources
PubMed1997

Long-term in vivo alterations of polyester vascular grafts in humans.

OBJECTIVES: To examine the influence of in vivo hydrolysis on the physical properties of polyester grafts and their correlation to the period of implantation in the human body. MATERIALS AND METHODS: Sixty-five explanted vascular grafts were obtained after 0-23 years of implantation due to suture aneurysms (18), occlusion (12), graft infection (12), failure of graft material (7) and post-mortem (16). The surface was examined by scanning electron microscopy, the molecular integrity by infra-red spectroscopy and physical strength by probe puncture. RESULTS: Scission of macromolecular chains and loss of strength were shown. It was demonstrated that hydrolytic degradation of polyester takes place with increasing time of implantation in humans. Analysis by linear regression showed that polyester grafts lose 31.4% of their bursting strength in 10 years and 100% in 25-39 years after implantation. CONCLUSIONS: Regular follow-ups of patients with aged vascular grafts and the precise documentation of implanted materials are necessary to estimate graft degradation.

Blood Vessel Prosthesis↗
PubMed1996

[Infrarenal abdominal aortic aneurysm--indications for surgery and survival].

PURPOSE: Elective operation is an established therapy in the management of infrarenal aortic aneurysms. Surgery has an acceptable low risk in the presence of experienced surgeons and anaesthetists. Indication for surgery nevertheless remains a difficult problem, because diagnostic procedures and evaluation of different criteria do not exactly predict the likelihood of rupture. Indication for surgery is moreover dependent on operative mortality and late survival. This study analyses early and late results associated with the repair of abdominal aortic aneurysms in our institution in Hamburg and comments on indication for elective surgery. METHODS: Life-Table analysis was used to determine survival rate. Calculation of expected prevalence of abdominal aortic aneurysms in the Hamburg population was based on demographic statistics and results in the literature. RESULTS: Between January 1981 and April 1995 1242 patients underwent abdominal aortic aneurysm repair, 1018 electively, 224 for ruptured aneurysm. Operative mortality was 4% and 50% respectively. The survival rate after elective operation was 64% at 5, 43% at 10 and 35.4% at 14 years, while after emergency surgery for ruptured aneurysm it was 40% at 5, 31.9% at 10 and 29.8% at 14 years. The survival rate of survivors after repair for ruptured aneurysms is similar to that after elective surgery. Over a 13 years period the rate of ruptured aneurysms did not decrease. Comparison of surgical data and calculated prevalence data show that a three times higher operative activity is requested to repair all occurring abdominal aortic aneurysms larger than 5 cm in diameter. CONCLUSIONS: In order to reduce the still high mortality associated with aneurysm rupture there is still a need for more prophylactic surgery.

Aged↗
PubMed1991

[Inflammatory aneurysms of the abdominal aorta].

The so-called "inflammatory" aneurysm of the aorta of the abdominal wall is a special form of the arteriosclerotic aneurysm of the aorta observed in 5-15% of the abdominal aorta aneurysms. It is characterized by more or less marked periaortal fibrotization. The pathological correlate is represented by lymphocytous and plasmacellular infiltrates that are mainly seen and identified in the region of the adventitia. The etiology has not yet been clarified. Since surgery of the inflammatory aneurysm of the abdominal wall aorta is rendered difficult due to neighbouring organs (e.g. ureters) becoming callous and adhesive, safe preoperative diagnosis is desirable. Suspicion of an aneurysm of the abdominal wall can be fairly safely confirmed by sonography. In case of a partially thrombotic aneurysm a characteristic fourfold stratification can be seen: free lumen/thrombus/calcified wall of aorta/law-echo outer layer. This last-named layer--the "inflammatory" portion--is tapelike, semicircular and more or less strongly developed. The inflammatory aneurysm of the abdominal wall is often symptomatic. Hence, the most important differential diagnosis concerns the covered perforation and the dissecting aortic aneurysm, as well as Ormond's disease, periaortal lymphomas and other retroperitoneal tumours.

Aorta, Abdominal↗
PubMed1990

[Late results after surgery of ruptured abdominal aortic aneurysm].

From 1981 to 1989, 695 patients with an infrarenal aortic aneurysm underwent surgery. In 114 cases the aneurysm was ruptured. The late results demonstrated, that after successful operation a patient's subsequent course was similar to that after an elective operation. Infarct and insult were the main causes of death in the postoperative period. Sonographic findings complete the postoperation analysis of the patient's later course.

Aged↗