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Byline: Yasuhiro Kouchi, Yoko Onuki, Moses Hong-De Wu, Qun Shi, Lester R. Sauvage Abstract: Objective: The purpose of this study was to evaluate in dogs the effect of blood flow alteration on caliber and morphology of in situ internal thoracic arteries. Methods: Six dogs underwent creation of a unilateral distal arteriovenous fistula between the internal thoracic artery and vein at the sixth rib to create high flow, and in six others the internal thoracic artery was unilaterally skeletonized and dissected. For both groups the contralateral internal thoracic artery served as the control; sides were alternated among cases. Blood flow was measured for shear stress calculation before and after surgical alteration. After 2 months, internal thoracic arteries were harvested with the entire anterior chest plate, which was dynamically inflated and fixed with 10% formalin at a controlled pressure of 120 mm Hg after angiography had been done at the same pressure. The luminal diameters were then measured at eight levels on the angiograms. Arterial tissue samples were taken at three levels and embedded, sectioned, and treated with hematoxylin-eosin and Verhoeff-van Gieson stains. Digital imaging analysis was used for quantitative morphometric studies. Results: All fistulas remained patent. In comparison with control arteries, high-flow internal thoracic arteries dilated and low-flow internal thoracic arteries narrowed, which was associated with significant change in shear stress for both groups. There were no substantial structural changes in the walls of either group. Conclusion: In the dog, the luminal diameter of the internal thoracic artery responds to altered blood flow without intimal thickening or other undesirable wall changes. (J Thorac Cardiovasc Surg 1997;113:114-20) Article History: Received 26 December 1995; Revised 6 February 1996; Revised 28 June 1996; Accepted 8 July 1996 Article Note: (footnote) [star] Address for reprints: Lester R. Sauvage, MD, The Hope Heart Institute, 528 18th Ave., Seattle, WA 98122., [star][star] 0022-5223/97 $5.00 + 0 12/1/76351

Byline: Hiroki Yoshida, Moses Hong-De Wu, Yasuhiro Kouchi, Yoko Onuki, Qun Shi, Lester R. Sauvage Abstract: The internal thoracic artery is preferable to the saphenous vein for use as a conduit for coronary artery bypass. More extensive use is possible if this artery is mobilized in a skeletonized form to provide greater length. Internal thoracic arteries are usually mobilized with cauterization. This study compared the effectiveness and effects on neighboring areas of division of the branches of the canine internal thoracic artery with bipolar cauterization and monopolar cauterization. Branch closure was significantly more secure in the bipolar cauterization group, with bleeding in 25 (9%) of 279 branches of 15 internal thoracic arteries treated with monopolar cauterization, in contrast to bleeding in 4 (1.3%) of 306 branches in the 15 internal thoracic arteries treated with bipolar cauterization, which were paired with the group treated with monopolar cauterization. The group of internal thoracic arteries treated with monopolar cauterization had a significantly higher prevalence of leakage when luminal pressure was increased from 120 to 160 mm Hg. Scanning electron microscopy demonstrated partial loss of endothelial cells on the flow surface of internal thoracic arteries treated with bipolar cauterization, compared with almost complete loss of endothelial cells around the orificial areas after monopolar cauterization. Secondary bipolar cauterization treatment caused only slightly more damage than primary treatment, but secondary monopolar cauterization was much more severe and extensive than primary treatment. These data suggest that bipolar cauterization is preferable to monopolar cauterization for skeletonized dissection of the internal thoracic artery. (J THORAC CARDIOVASC SURG 1995;110:504-10) Author Affiliation: Seattle, Wash. Article History: Received 2 September 1994; Accepted 28 December 1994 Article Note: (footnote) [star] From The Hope Heart Institute, the Providence Medical Center, and the Department of Surgery, University of Washington School of Medicine, Seattle, Wash., [star][star] Address for reprints: Lester R. Sauvage, MD, 528 18th Ave., Seattle, WA 98122., a 0022-5223/95 $3.00 + 0, aa 12/1/63179

p: < 0.05). The neointima, which contained smooth muscle cells, was formed as early as 2 weeks in the vein-wrapped grafts. There were no differences in the speed of healing or in healing patterns according to whether the intimal or the adventitial side of the inferior vena cava was placed against the graft. Histologic findings did not support the hypothesis that accelerated flow surface endothelialization results in direct migration of endothelial cells from the intima of the vein wrap, and there was no clear correlation between the surface endothelial-like cell coverage and microostia. To gain further insight into why accelerated healing occurs in this model, earlier observations accompanied by molecular biology analysis are needed, and vein wrap studies provide a method of comparison for this work.

To ascertain the histologic relationship between flow surface microostia and perigraft vessels in the healing of a porous vascular prosthesis, a series of careful histologic examinations were carried out on a preclotted, knitted Dacron graft, 8 mm in diameter and 7 cm long, after implantation in the canine infrarenal abdominal aorta for 3 months. Four adjacent longitudinal tissue blocks were taken from the middle for evaluation by means of light microscopy, scanning electron microscopy, transmission electron microscopy, and immunocytochemical staining, and the remainder of the specimen was stained with silver nitrate to allow visualization of microostia and cell borders on the flow surface. Following identification of two microostia adjacent to the area where samples had been taken for general healing evaluation, a 3 × 8 mm full-thickness block containing the microostia was embedded in glycol methacrylate and stained with hematoxylin and eosin. Of 240 serial sections cut from this block, 80 were prepared and examined. Silver staining revealed 42 microostia on the flow surface. Light, scanning, and transmission electron microscopy with endothelial factor VIII/von Willebrand factor stain confirmed a single layer of endothelial cells on the flow surface, and beneath was a well-organized neointima containing fusiform cells confirmed as smooth muscle by α-actin stain. Light microscopy of the serial sections revealed transmural microvessels, lined with endothelium, extending continuously between the flow surface ostia and the perigraft vessels in this porous vascular prosthesis.

The purpose of the present study was to assess the diagnostic utility of blood flow measurements at the sigmoid colon by laser Doppler flowmetry.Methods: A laser-Doppler flow probe was placed in contact with the serosa of the sigmoid colon in 41 patients undergoing resection of infrarenal abdominal aortic aneurysms. Blood flows were measured before aortic clamping, after reconstruction, and after inferior mesenteric artery revascularization.Results: The authors observed a colonic blood flow greater than 18 mL/minute/100 g in all the patients who did not develop postoperative ischemic colitis.Conclusions: The colonic blood flow needed to prevent postoperative ischemic colitis is greater than 18 mL/minute/100 g. The assessment of blood flow at the sigmoid colon by laser Doppler flowmetry is useful for predicting postoperative ischemic colitis.

The purpose of this report was to study effects of shear force and hemodynamic conditions that influence fallout healing in the arterial and venous systems of the same dog. Knitted Dacron grafts made impervious by a 1.5 mm thick coat of silicone rubber bonded to the external surface were implanted for 4 weeks during the same surgery in the descending thoracic aorta (DTA), abdominal aorta (AA) and inferior vena cava (IVC) of each of five dogs. Flow rates were measured during surgery and shear stresses calculated with the Hagen-Poiseuille formula. Full-wall thickness longitudinal tissue sections were embedded in resin and stained with hematoxylin and eosin for light microscopy, and in paraffin for immunocytochemistry studies with Factor VIII/von Willebrand factor, smooth muscle α-actin, collagen IV, laminin, and proliferating cell nuclear antigen. Scanning electron microscopy and transmission electron microscopy studies were also performed. AgN03was used to determine percentage of endothelial-like cell coverage on the flow surface. All grafts were patent, without hematoma or seroma. Endothelial-like cell coverage was highest in the IVC grafts and lowest in the DTA. Shear stress and flow velocity were significantly lower in IVC grafts than DTA and AA. Proliferating cell nuclear antigen indicated extensive cellular proliferation in the intima and in the interstices of the inner portion of the graft wall. The degree of fallout healing in knitted Dacron grafts made impervious by an external coat of silicone rubber varies inversely with the sheer force of blood flow in these grafts.

= 4), 8 days (n= 5), 9 days (n= 4), 10 days (n= 3), 11 days (n= 4) and 12 days (n= 3) postoperatively. Graft surfaces were evaluated for thrombus coverage, cell coverage, and the number of micro-ostia. Components and cellular types in the graft wall and on the surface were studied and characterized with H&E, histochemical, and immunocytochemical staining. BrdU labeling was also used, to identify the areas where cells were actively proliferating. All grafts were patent. Although the degree of IVC/graft attachment varied, isolated islands of endothelial-like cells were found at the midgraft areas at each time period, and immunocytochemically confirmed as endothelial cells. There were two healing patterns: (1) surface endothelialization before microvessel/tissue ingrowth from the perigraft areas, and (2) surface endothelialization with full wall microvessel and tissue presence. Surface endothelialization was observed before perigraft tissue ingrowth, indicating that fallout healing is an independent source of endothelialization for porous grafts.

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The purpose of this study was to investigate early arterial graft healing and its sources in porous Dacron prostheses after very short implantation periods in the dog, using extensive histologic examination of serial sections. Preclotted Dacron prostheses 6 cm long and 8 mm in diameter were implanted in the descending thoracic aorta (DTA) of 14 dogs, and retrieved at 7 days (n =6), 10 days (n= 4), and 14 days (n= 4). The flow surface was assessed for thrombus coverage, endothelial-like cell (ELC) coverage, and the number of microvessel ostia. Where an ELC island was identified under the stereomicroscope, full-wall longitudinal tissue samples were taken, and embedded in resin for light microscopy study of 6-µm, H&E-stained serial sections to determine general healing and interstitial tissue presence. If there was more than one ELC island, another full-wall sample was taken and embedded in paraffin for staining with laminin, collagen IV, and smooth muscle α-actin antibodies, and PTAH. All grafts were patent with very little thrombus. Islands of endothelial-like cells were found for each time period, and on all 14-day grafts. Endothelial-like cell coverage was highest at 14 days. On 7- and 10-day grafts, cells proved to be endothelium were found in the middle of the flow surface, unconnected to either pannus or perigraft tissue ingrowth. Healing occurs as early as 7 days in porous knitted Dacron grafts. The source at periods earlier than 10 days appears to be cells from the blood stream. (Ann Vasc Surg 1997; 11:604-611.)

We report herein the case of a 19-year-old woman, diagnosed as having Klippel-Trenaunay syndrome at the age of 3 years, who presented to our hospital with severe abdominal pain. Abdominal computed tomography revealed splenomegaly, ascites, and paracentesis confirming an intrabdominal hemorrhage. Thus, an emergency laparatomy was performed for a suspected splenic rupture, and 2.5L of blood was drained from the abdominal cavity. Splenomegaly was confirmed, and a splenectomy was performed. The patient's postoperative course was complicated by disseminated intravascular coagulation, but she recovered and was discharged 3 weeks following surgery. Pathological examination of the spleen suggested that the splenomegaly was caused by high venous pressure due to splenic vein stenosis. To our knowledge, this is the first reported case of Klippel-Trenaunay syndrome associated with marked splenomegaly.