BACKGROUND: Studies on tissue-engineered vascular scaffold construction mostly focus on biodegradable scaffold and acellular allogenic or xenogenlc vascular scaffold. However, there are some problems to be urgently solved, such as control of degradable speed of biodegradable scaffold, and donor-sourced bacterial virus infecting recipients during the implantation of acellular natural vascular scaffold.OBJECTIVE: This study was designed to treat allogenic blood vessels by ultrahigh pressure in conjunction with nuclease washing (decellularization) to observe the decellularization effects and porcine endogenous retroviras (PERV) removal.DESIGN: A controlled observation.SETTING: National Cardiovascular Center, Japan.MATERIALS: This study was performed at the National Cardiovascular Center, Japan from April 2004 to April 2005.Young healthy male 1-3-month-old minipigs, weighing 3-5 kg, were provided by Japanese Farm. The protocol was performed in accordance with ethical guidelines for the use and care of animals. The main reagents and equipments used in the present study were as follows: Hoechst 33258 (Dojindo Laboratories, Kumamoto, Japan), ultrahigh pressure device (KOBELCO, Kobe Steel, Ltd, Japan), and PCR (GENEAMP PCR SYSTEM 9700).METHODS: Porcine descending aorta vessels were isolated under a sterile condition and treated by cold isostatic pressing (981 MPa, 4 ℃) for disruption of donor cells. The cell debris was digested by nuclease and washed out by phosphate buffered saline for vascular scaffold.MAIN OUTCOME MEASURES: After processing of decellularization by ultrahigh pressure treatment, vascular DNA levels were quantitatively determined by a fluorescent probe (Hoechst 33258); Removal of cell components from vascular tissue and retention of scaffold fibers were observed by a transmission electron microscope (JEM 100 cx); Scaffold ultrastructure was observed via a scanning electron microscope (JBM 5200); The morphological structure of vascular wall was observed via an optical microscope (100 augmentation) . All these were performed to evaluate the antigen-removal effects of decellularization by ultrahigh pressure treatment from histological, molecular biological, and immunohistochemical standpoints. Proviral DNA levels of acellular PERV were measured by PCR to evaluate the effects of decellularization by ultrahigh pressure treatment on killing PERV, a typical pathogenic microorganism.RESULTS: After decellularization by ultrahigh pressure treatment, the wavy structure of fibers was completely retained, and tissues were thoroughly cell free. Transmission electron microscope results demonstrated that collagen fibers and elastic fibers, but not cell components were detectable. Scanning electron microscope results demonstrated that only acellular scaffold was found. There was no PERV detected in the treated tissues. However, the PERV could not be inactivated in the tissues treated by surface active agent. Intravascular DNA levels significantly altered from (31.7±3.5 ) mg/L pre-decelhilarization by ultrahigh pressure treatment to (1.16±0.23) mg/L post- decellularization by ultrahigh pressure treatment(P＜0.01). Results demonstrated that decellularization by ultrahigh pressure treatment ridded of cellular nucleus and contents mostly.CONCLUSION: The study demonstrated that decellularization by ultrahigh pressure treatment could fundamentally rid cell components of scaffold, and concomitantly inactivate PERV successfully.

To evaluate the efficacy of the retroperitoneal approach (RP) when compared with the transperitoneal approach (TP) in elective aortoiliac reconstruction, 41 cases were reviewed. From February 1987 through October 1991, 16 patients underwent aortoiliac reconstruction through the TP approach and 25 patients underwent operation through the RP approach for abdominal aortic aneurysms (AAA). The TP approach was associated with larger intraoperative blood loss (648.6±416.5ml) when compared with the RP approach (357.7±208.9ml) (p<0.01). The TP approach was associated with greater intraoperative blood transfusion (2093.8±1179.0ml) when compared with the RP approach (1010.4±905.3ml) (p<0.01). Both groups had similar operative times. Postoperative initiation of oral water intake was prolonged in the TP group (50.2±27.4hr) when compared with the RP group (22.3±8.9hr) (p<0.01). Postoperative initiation of walking training was prolonged in the TP group (88.7±37.1hr) when compared with the RP group (60.1±23.2) (p<0.01). This experience demonstrates that the RP approach is a preferable alternative to the TP approach in elective aortoiliac reconstruction.

Infectious arterial aneurysm in a rare condition with a high mortality because of rapid aneurysmal growth and subsequent rupture. We encountered 3 cases of arterial aneurysm due to Salmonella infection. We evaluated there 3 cases and an additional 14 cases reported in the Japanese literature. Eleven patients with Salmonella infection had bacteremia. The incidence of bacteremia in patients with Salmonella infection was more frequent than that in patients with other bacillary infections. The location of the aneurysm was the abdominal aorta in 14. Rupture or impending rupture of the aneurysm was identified in 12. Fifteen patients underwent operation including in situ reconstruction in 9 and extra-anatomic bypass in 6. Among 15 patients who underwent an operation, 14 survived. These data suggest that accurate preoperative diagnosis, long-term antibiotic therapy, and immediate surgical intervention are essential for effective treatment of arterial aneurysm due to Salmonella infection.

A 73-year-old man who had undergone Y-grafting suffered from septicemia. A culture of arterial blood yielded Bacteroides fragilis. Computed tomography showed abscess and gas around the prosthetic graft. Under a diagnosis of a prosthetic graft infection caused by Bacteroides fragilis, removal of the infected graft, extra-anatomic bypass and omental grafting were performed 13 days after the first operation. After intensive treatment, he recovered and was discharged on the 45th day postoperatively.

A 71-year-old woman who had Takayasu's disease underwent Y-grafting, bypass grafting between the abdominal aorta and left renal artery with 8mm ePTFE graft and right nephrectomy for infrarenal abdominal aortic aneurysm and renovascular hypertension (RVH). Four years after the first operation, the bypass graft became occluded and hypertension was exacerbated. Magnetic resonance angiography revealed that the left renal artery was supplied by the collateral arteries. We performed replacement of the thoracoabdominal aorta and reconstruction of the left renal artery using the saphenous vein. Postoperatively serum creatinine level decreased and hypertension was controllable. She was discharged from the hospital and has been well for three years.

A 52-year-old man who had liver cirrhosis sufferred ruptured thoraco-abdominal aortic aneurysm. This patient was classified as having Child's class B liver cirrhosis preoperatively. The thoracoabdominal aorta was successfully replaced with reconstruction of the renal arteries, superior mesenteric artery, celiac artery, and 10th intercostal artery. Omentopexy was added. As persistent ascites continued postoperatively, peritoneovenous shunting was performed on the 29th postoperative day. Ascites disappeared and 20 days later the patient was discharged from hospital and has been well for two years.

A 61-year-old man fell into out-of hospital cardiopulmonary arrest due to rupture of an abdominal aortic aneurysm, and was resuscitated onsite. On arrival at the emergency room, a fusiform type abdominal aortic aneurysm and massive hematoma in the retro-peritoneal space were detected by ultrasonography. Quickly, an aortic occlusion balloon catheter was placed at the proximal site of abdominal aorta through the left brachial artery, and then graft replacement of the aneurysm was carried out. The inferior mesenteric artery was occluded, and was not reconstructed. Five hours after the operation, left hemi-colectomy was carried out for ischemic necrosis of the descending to sigmoid colon. Although he was complicated by multiple organ failure; renal failure, liver dysfunction, severe infection, and brain infarction, he survived without a fatal disability. A rare case with ruptured abdominal aortic aneurysm who fell into cardiopulmonary arrest outside the hospital but survived after bowel necrosis and multiple organ failure is reported.