Fumio Iwaya

Intravascular Imaging Methods for Venous Disorders.

The purposes are to assess the problems associated with intravascular imaging methods such as angioscopy and intravascular ultrasound (IVUS) and to evaluate their efficacy through the results of our observations. A total of 54 limbs in 53 patients, 50 patients with chronic venous insufficiency and 3 patients with deep vein thrombosis, were diagnosed and operated on using angioscopy (Olympus OES, order made type) and IVUS (Endosonics, model 82700). The imaging catheters were inserted through a branch of the long saphenous vein and the valves and the intraluminal views were observed. By angioscopy, intraluminal views were clearly observed in 98% of all lesions. However, observation became more difficult in iliac veins compared to in femoral and in long saphenous veins (p<0.01). Venous wall and thrombus were detected more by IVUS than by angioscopy (p<0.01), but only 21 valves (24%) were visualized by IVUS among the 88 valves observed by angioscopy. The intravascular imaging method of angioscopy is more suitable for observing valves and intraluminal views compared with IVUS, whereas IVUS is more suitable for observing the cross-sectional venous wall.

Postoperative Alteration in the Size of Dacron Vascular Prostheses Implanted in the Infrarenal Abdominal Aorta

The degree and significance of postoperative alteration in the size of Dacron grafts in the infrarenal abdominal aorta was assessed by computed tomography. We studied a total of 41 knitted Dacron fabric grafts, comprising 28 Gelseal triaxial grafts and 13 Hemashield Microvel grafts, and 29 woven Dacron fabric (Veri-Soft Woven) grafts which were used to replace the infrarenal abdominal aneurysms. These three types of Dacron fabric dilated immediately after replacement to 1.4–1.5 times the manufactured size, but did not dilate further after the surgery.

Prevention of paraplegia in transluminally placed endoluminal prosthetic grafts for descending thoracic aortic aneurysms

OBJECTIVE To evaluate the efficacy of a temporary balloon occlusion test for the prevention of paraplegia following transluminally placed endoluminal prosthetic grafts for descending thoracic aortic aneurysms. SUBJECTS AND METHODS Two occlusion balloons were inserted via the brachial and femoral arteries and positioned in the proximal and distal neck of the descending thoracic aortic aneurysms using fluoroscopy. After temporary occlusion of the thoracic aorta by inflation of both the proximal and distal balloons, the evoked spinal potential was measured for 15 mins. A maximum amplitude during temporary balloon occlusion test decreasing by more than 20% of the pre-balloon occlusion level was considered to be significant, enough to not perform transluminally placed endoluminal prosthetic grafts, but instead an open repair. The test was applied in 12 cases (9 males and 3 females, 50-86 years old). All aneurysms were located between the Th6 and Th12 with a maximum diameter of 40-70 mm, and average of 56 mm. RESULTS The changes in maximum amplitude of evoked spinal potential remained within 20% of the value before balloon occlusion in 11 cases. Transluminally placed endoluminal prosthetic grafts were performed in these 11 cases and no instance of paraplegia or other complication relating to the test was observed. Deployment of stent-grafts was successful in 10 cases (91%). CONCLUSION It is suggested that the preoperative measurement of evoked spinal potential during temporary balloon occlusion is clinically useful for the assessment of the risk to paraplegia occurring in transluminally placed endoluminal prosthetic grafts.

Graft-wall endoleak 18 months after successful endoluminal AAA repair

Purpose: To describe a case of graft-wall endoleak 18 months after successful endoluminal repair of an abdominal aortic aneurysm (AAA). Methods and Results: A 71-year-old man with infrarenal AAA was successfully treated with an endoluminal aortomonoiliac graft and femorofemoral crossover bypass with surgical ligation of the right external iliac artery. The stent-graft was made from 2 Gianturco Z-stents and a tapered thin-walled (0.1-mm) Dacron graft. Eighteen months after endografting, the patient complained of a pulsatile abdominal mass. Angiography and computed tomography showed graft-wall endoleak. Aneurysmectomy was performed, and the aneurysm was successfully replaced with a Y-shaped knitted Dacron graft. A hole in the graft wall was found 3 cm from the proximal edge of the stent-graft. Conclusions: This case suggests that the use of thin-walled graft material in endografts may not be sufficiently durable.

The Appearance of Cytokines and Adhesion Molecules in Saphenous Vein Valves in Chronic Venous Insufficiency

Objective: To evaluate the difference between competent valves and incompetent valves with regards to the development of expression of cytokines and adhesion molecules in primary varicose veins. Methods: Specimens were obtained from 13 patients with primary varicose veins during surgery. Valves were classified according to the angioscopic findings: 8 competent and 17 incompetent valves; type I (7 valves with elongated cusps) and type II (10 valves with expansion of commissures). The mRNA levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), tumour necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and endothelial leucocyte adhesion molecule-1 (ELAM-1) were measured by polymerase chain reaction (PCR) amplification of cDNA reverse-transcribed from RNAs. Results: In all cases there were few appearances of IL-6, IL-8 and TNF-α at the valve cusps. TGF-β and VCAM-1 levels were highly elevated in the cusps of incompetent valves compared with competent valves (p<0.05). At the venous wall IL-6 and IL-8 occurred more frequently in incompetent valves than in competent valves (p<0.05). Conclusion: This study suggests that inflammatory cytokines and adhesions molecules, especially TGF-β, IL-6, IL-8 and VCAM-1, may be related to the occurrence of valve insufficiency.

Bland white Garland syndrome with type A aortic dissection.

We report the case of a 72-year-old patient with a left main coronary artery originating from the pulmonary trunk with type A aortic dissection. He is the oldest patient among those reported in the literature, operated due to acute type A aortic dissection and has survived 4 year after the operation without surgery on the coronary artery.

Cardiopulmonary bypass system-mountable anesthetic machine

Miniaturization of the cardiopulmonary bypass (CPB) system may provide several benefits, such as decreasing the manpower, cost, and amount of homologous blood required and improving patient care. We have proposed a portable CPB system-mountable anesthetic machine. Our portable CPB system consists of a bypass circuit, a hard shell reservoir, a membrane oxygenator, and two pumps. The reservoir has three chambers, one venous and two suction chambers. These three chambers can control the negative pressure when connected with an ordinary vacuum system in the operating room. Pumps are used for perfusion and blood transfer from suction to venous chamber. We have been working to create a newly designed pump for this system. This pump consists of a polycarbonate rotor with six polyurethane vanes and acrylic acid resin housing. The housing is narrowed at both the inflow and outflow ports. This pump has characteristics of a vane pump as well as a friction pump. By using a DC brushless motor, it is possible to perfuse from 0.1 to 10 l/min, under bench testing. Preliminary animal tests of its operation produced very satisfactory results. Regarding hemolysis, the plasma free hemoglobin level was below 80mg/dl after 4h of operation using two pumps. This low-cost disposable CPB system enables it to be used for the portable CPB system-mountable anesthetic machine.

Clinical results of transluminal atherectomy with laser angioplasty for arteriosclerotic obliterans

Abstract Total 13 cases 17 lesions with occlusive peripheral vascular disease were performed transluminal atherectomy with laser angioplasty(LAP) in our department of Cardiovascular surgery from January 1992 through October 1992 were subjected. Initial success rate(30 days patency) were 94 % (100 % in the stenotic lesions and 83 % in the occlusive lesions). The postoperative ankle pressure index(API) and stenotic rate statistically improved compared with the preoperative data (P < 0.01). Transluminal atherectomy with LAP was effective to protect arterial wall and decrease residual stenotic rate compared with laser assisted balloon angioplasty. This new technique might have further clinical application by improving the initial and long patency rate.