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Purpose: To determine if a complete intra-arterial environment affects endothelialization rate and basement membrane organization in polytetrafluoroethylene (PTFE) grafts., Method: Thirty dogs underwent either infrarenal abdominal aorta PTFE interposition (12) or intraluminal stented (18) grafting. Grafts were explanted at 4 and 8 weeks and rate of endothelial ingrowth calculated. Endothelial cells were identified and basement membrane organization assessed using antibodies against endothelial cell-specific surface antigen CD31, type IV collagen, and laminin., Results: Endothelialization rates, expressed as percent graft surface area coverage per week, were 3.7% +/- 0.62% (4-week control), 12.9% +/- 0.58% (4-week stented), 4.2% +/- 0.62% (8-week control), and 10.0% +/- 0.54% per week (8-week stented grafts). Endothelial repaving rates were constant for control and increased in all stented grafts (P <0.01). At 4 weeks, laminin was identified in all control (6 of 6) and no stented grafts. Staining was confined to the 20% of the hyperplastic intimal area immediately below the endothelium. At 4 weeks, type IV collagen was present throughout the entire hyperplastic intima in control specimens but was confined to a discrete subendothelial zone in stented grafts. By 8 weeks, type IV collagen became concentrated in the luminal one third of the intima in control grafts., Conclusion: Intra-arterial graft location is associated with early formation of an organized basement membrane and accelerated endothelialization in PTFE grafts.

Purpose: To investigate the effect of stent design and deployment mechanism on endoluminal graft healing., Method: Twenty dogs underwent infrarenal abdominal aorta polytetrafluoroethylene (PTFE) interposition (6) or intraluminal stented grafting using either a balloon expandable (BE, n = 8) or self-expanding (SE, n = 6) stent design. Grafts were removed at 8 weeks. Length of endothelial ingrowth and intima to media height ratios (IMHR) were calculated. Perianastomotic smooth muscle (Actin+), macrophage (CD44+), proliferating (PCNA+), and platelet-derived growth factor (PDGF+) cell content were determined., Results: Mean endothelial ingrowth was 1.10 +/- 0.15 cm (control), 1.88 +/- 0.13 cm (BESG), and 2.16 +/- 0.18 cm (SESG) proximally; and 0.94 +/- 0.12, 2.11 +/- 0.11 cm, and 2.16 +/- 0.15 cm, respectively, at the distal anastomosis. Endothelial ingrowth was greater in all stented grafts (P <0.001). Mean IMHRs were 1.42 +/- 0.16 (control), 0.50 +/- 0.14 (BESG), and 0.77 +/- 0.2 (SESG) proximally; and 0.84 +/- 0.1, 0.42 +/- 0.09, and 0.77 +/- 0.12 (SESG) distally. Lower IMHRs were observed in all stented graft regions (P <0.05) except the distal anastomosis of SESG. The PDGF+ and PCNA+ cell content was decreased, and Actin+ cell content was increased in all stented grafts (P <0.05)., Conclusion: Intraluminal location enhances endothelialization and attenuates intimal thickening in PTFE grafts. The enhanced healing of intraluminal stented grafts is irrespective of the type of stent or deployment mechanism used.

In patients with inferior vena cava (IVC) injuries, predictors of survival are investigated. From 1987 to 1995, 27 IVC injuries were identified among 514 patients with vascular trauma. The ability of clinical determinants to predict survival were retrospectively assessed. IVC injuries occurred in 7 females and 20 males (mean age, 27.7 +/- 2.5 years) from both blunt (n = 14) and penetrating (n = 13) trauma. The mean revised trauma score was 10.2 +/- 0.6. Injuries were treated by primary repair (n = 22), ligation (n = 4), or prosthetic grafting (n = 1). Thirteen patients died (48%), 10 within 12 hours of admission. Suprahepatic (n = 2), retrohepatic (n = 12), suprarenal (n = 1), and infrarenal (n = 12) injuries were associated with 100, 67, 100, and 20 per cent mortality, respectively. Blood transfusions (16 +/- 4 vs 23 +/- 4 units), coagulation factor replacement (7 +/- 2 vs 7 +/- 2 units), and electrolyte solution use (8.6 +/- 1.4 vs 9.6 +/- 1.4 L) were similar among survivors and nonsurvivors. Four complications [venous hypertension (n = 2), IVC thrombosis (n = 1), and pulmonary embolus (n = 1)] occurred in the 14 survivors (28.6%). Blunt injury, revised trauma score, free perforation, injury location, intraoperative hypotension, and blood loss were predictive of mortality. IVC injuries remain extremely lethal, and improved survival is associated with infrarenal penetrating injuries and a contained hematoma.

Previous investigations reveal in the absence of endothelial cell (EC) injury, intraarterial polytetrafluoroethylene (PTFE) stent graft (SG) exhibit greater EC repaving than PTFE interposition grafts (CG). The investigation evaluated EC repaving of SG compared to CG after balloon injury. Twenty adult dogs underwent SG (n = 10) or CG (n = 10) placement in the infrarenal aorta after balloon injury with harvest at 1 and 6 weeks. Endothelial repaving, intima-to-media height ratios (IMHR), and inflammatory stains were performed. Endothelial repaving was greater in 6-week SG compared to CG (51% +/- 5.0 versus 10% +/- 5.0, p < or = 0.05). IMHR was less in 6-week SG compared to CG at the proximal (1.22 +/- 0.16 versus 1.82 +/- 0.16, p < or = 0.05) and distal anastomosis (0.81 +/- 0.25 versus 1.33 +/- 0.25, p < or = 0.05). Smooth muscle cell (SMC) alpha-actin was greater in 1-week SG compared to CG at the distal anastomosis (121.5 +/- 7.2 versus 94.0 +/- 7.2, p < or = 0.05). Proliferating cell nuclear antigen (PCNA) was less in 6-week SG compared to CG at the proximal (5.6 +/- 1.4 versus 9.4 +/- 1.1, p < or = 0.05) and distal anastomosis (3.8 +/- 0.6 versus 11.2 +/- 1.1, p < or = 0.05). Macrophage CD-44 was less in 6-week SG compared to CG at the proximal (10.4 +/- 1.6 versus 32.6 +/- 3.6, p < or = 0.05) and distal anastomosis (8.6 +/- 0.9 versus 35.6 +/- 3.6, p < or = 0.05). Intraarterial SG placed after balloon injury exhibited significantly greater endothelialization and less intimal hyperplasia when compared to CG.

Lower extremity trauma with concomitant orthopedic and vascular injury is associated with a high degree of limb loss. Despite successful arterial repair, many patients will ultimately require amputations. The effect of associated orthopedic injuries on limb loss in patients with lower extremity arterial injuries is investigated. From 1989 to 1994, 52 infrainguinal arterial injuries were identified among 365 vascular trauma patients. Clinical determinants were retrospectively assessed for the ability to predict postoperative amputations. Femoral artery injuries were present in 23 patients, with 53 per cent the result of blunt trauma. The incidence of lower extremity fractures was 53 per cent (60% open). Seventy-nine per cent of femoral artery injuries were repaired with saphenous vein grafts. Popliteal artery injuries were present in 13 patients, with 77 per cent the result of blunt trauma. The incidence of lower extremity fractures and posterior knee dislocations was 85 per cent (73% open) and 38 per cent, respectively. Ninety-two per cent of injuries were repaired with saphenous vein grafts. Tibial artery injuries were present in 16 patients, with 44 per cent the result of blunt trauma. The incidence of lower extremity fractures was 81 per cent (46% open). Twenty-five per cent of tibial artery injuries were treated with arterial repair, and 31 per cent with arterial ligation. Fourteen above-knee (AKA) and two below-knee amputations were performed. Amputation rates were 26.1 per cent (three AKAs) for femoral, 53.8 per cent (seven AKAs) for popliteal, and 38 per cent (four AKAs, two below-knee amputations) for tibial artery injuries. At the popliteal and femoral locations, greater than two long-bone fractures was predictive of amputation. For tibial arteries, one-vessel (n = 10), two-vessel (n = 3), and three-vessel (n = 3) injuries were associated with 20, 33, and 100 per cent amputations rates, respectively. Blunt injury, pulseless extremity, need for arterial repair (rather than ligation or no therapy), increasing number of injured tibial vessels, and multiple long-bone fractures were predictors of amputation (P < 0.05). Distal vascular injuries combined with complex orthopedic fractures are more likely to result in limb loss. Two or more long-bone fractures is predictive of amputation at all three locations.

Background: Intraluminally placed polytetrafluoroethylene grafts are associated with enhanced graft endothelialization and diminished intimal hyperplasia when compared with interposition grafts. This study determined the role of platelet-derived growth factor in intraluminal graft healing., Study Design: Thirty dogs underwent infrarenal abdominal aorta polytetrafluoroethylene interposition (control, n = 15) or intraluminal stented (n = 15) grafting. Grafts were explanted at 1, 3, and 6 weeks. The percent of graft area endothelialization and intima to media height ratios were calculated. By using protein electrophoresis and the Western blot technique, platelet-derived growth factor, identified by immunolabeling with anti-platelet-derived growth factor antibody, was isolated from proximal, mid-, and distal graft regions and was quantified using densitometry., Results: Graft area endothelialization was 0 +/- 3.3 percent, 2.3 +/- 3.3 percent, and 19.0 +/- 3.3 percent for 1-, 3-, and 6-week controls; and 4.7 +/- 3.7 percent, 30.5 +/- 3.3 percent, and 86.8 +/- 3.3 percent for 1-, 3-, and 6-week stented grafts. Endothelialization was greater in stented grafts at 3 and 6 weeks (p < .01). Proximal anastomosis intima to media height ratios were 1.61 +/- 0.15, 1.54 +/- 0.14, and 1.48 +/- 0.15 for 1-, 3-, and 6-week control grafts, and 0.42 +/- 0.18, 0.41 +/- 0.15, and 0.47 +/- 0.14 for 1-, 3-, and 6-week stented grafts. Similar intima to media height ratio values were present at the distal anastomosis. Lower intima to media height ratios were observed in all stented grafts (p < .01). The platelet-derived growth factor content at 1-, 3-, and 6-weeks was lower in all stented grafts when compared with controls. The content of platelet-derived growth factor was greatest in 3-week controls, with a significant difference noted in the mid-graft region (p < .05). The content of platelet-derived growth factor remained stable in all stented graft regions over 6 weeks. An inverse correlation between stented graft platelet-derived growth factor content and endothelialization (r = -0.43) and a positive correlation with proximal anastomotic intimal hyperplasia (r = 0.73) were identified., Conclusions: Lower platelet-derived growth factor content is associated with decreased intimal hyperplasia and improved healing in intra-arterial polytetrafluoroethylene grafts.

Background: The purpose of this study was to investigate the effect of complete intraluminal placement on prosthetic graft healing., Methods: Thirty dogs underwent infrarenal abdominal aorta polytetrafluoroethylene interposition (12) or intraluminal stented (18) grafting. Grafts were removed at 4 and 8 weeks. Length of endothelial ingrowth and intima to media height ratios (IMHRs) were calculated. Perianastomotic endothelial (CD31+, factor VIII [FVIII+]), smooth muscle (actin+), macrophage (CD44+), and proliferating (PCNA+) cell content was determined., Results: In control grafts mean proximal and distal anastomotic endothelial cell ingrowth was 0.42 +/- 0.06 and 0.47 +/- 0.08 cm at 4 weeks and 1.10 +/- 0.24 and 0.94 +/- 0.17 cm at 8 weeks. In intraluminal grafts mean proximal and distal anastomotic endothelial cell ingrowth was 1.57 +/- 0.09 and 1.54 +/- 0.12 cm at 4 weeks and 1.88 +/- 0.06 and 2.11 +/- 0.25 cm at 8 weeks. Endothelial ingrowth was greater in all stented grafts (p < 0.001). Mean proximal anastomosis IMHRs were 1.01 +/- 0.16 for 4-week and 1.42 +/- 0.16 for 8-week control grafts and 0.59 +/- 0.18 for 4-week and 0.50 +/- 0.14 for 8-week stented grafts. Similar IMHR values were present at the distal anastomosis. Lower IMHRs were observed in stented grafts (p < 0.05). Content of CD44+, PCNA+, and FVIII+ cells were reduced both proximally and distally in 4-week stented grafts (p < 0.05). Distal content of CD31+ and actin+ cells was greater in 4-week stented grafts (p < 0.05). At 8 weeks CD44+ cell content decreased in controls (p < 0.05)., Conclusions: Intraluminal location enhances prosthetic graft reendothelialization and attenuates intimal thickening.

To determine the effects of intraluminal placement on peri-anastomotic intimal hyperplasia and platelet derived growth factor (PDGF) secretion in polytetrafluoroethylene (PTFE) grafts. Infrarenal aortic PTFE grafts were placed in 30 dogs as either interposition (n = 12) or intraluminal stented (n = 18) grafts. Grafts were explanted at 4 and 8 weeks. At each anastomosis, intima to media height ratios (IMHR) were calculated, and smooth muscle (Actin), proliferating (PCNA), and PDGF secreting cell content determined using cell-specific immunohistochemical stains. At the proximal anastomosis, control and stented graft IMHRs were 1.01 +/- 0.16 vs 0.59 +/- 0.18 in 4-week and 1.42 +/- 0.16 vs 0.50 +/- 0.14 in 8-week specimens. Similar IMHR values were present for the distal anastomosis. Peri-anastomotic PCNA cell counts were greater in control grafts at both 4 and 8 weeks. Stented grafts were associated with diminished IMHR and PCNA+ content at both 4 and 8 weeks (P < 0.05). PDGF+ content was similar among control and stented grafts at 4 weeks, while lower in stented grafts at 8 weeks (P < 0.05). At the distal anastomosis, a correlation between PDGF secretion and Actin+ cell content was observed in control grafts at 4 (r = 0.74) and 8 (r = -0.56) weeks. Cell proliferation was associated with PDGF content in 4-week intraluminal and 8-week control grafts (P < 0.05). Changes in IMHR were not the result of differential PDGF secretion. Intraluminal location attenuates intimal hyperplasia in PTFE grafts. The reduced intimal hyperplasia and improved healing of endoluminal grafts could not be attributed to lower PDGF content alone.

Purpose: To investigate the effect of anesthetic technique on cardiac morbidity after carotid artery surgery., Patients and Methods: From 1991 to 1994, 266 consecutive carotid endarterectomies were performed under local/regional (n=140) or general anesthesia (n=126). The effects of anesthetic technique on postoperative adverse cardiac events were assessed retrospectively., Results: Preoperative cardiac testing was performed in all patients undergoing general or local/regional anesthesia. Medical characteristics were similar among patients in both groups. Forty-seven adverse cardiac events (4 myocardial infarction, 9 congestive heart failure, 7 angina, and 27 new ventricular dysrhythmias) occurred postoperatively in 38 patients (14.3%). There were no deaths. The relative risks of general anesthesia for dysrhythmias, myocardial infarction, angina, congestive heart failure, and total adverse cardiac events were 2.22, 0.37, 0.83, 1.38, and 1.5, respectively. The only statistically significant differential was the increased risk of postoperative dysrhythmias after general anesthesia (P<0.03)., Conclusions: Major cardiac morbidity following carotid endarterectomy is independent of anesthetic technique.

Background: Absence of cardiac symptoms is not a valid indicator of low cardiac risk in the sedentary patient who is being considered for vascular surgery. Invasive methods of cardiac assessment in such patients are associated with risk and are expensive. This study was carried out to evaluate the utility of pre-operative cardiac risk stratification with dipyridamole myocardial scintigraphy (DMS), in patients to undergo carotid artery surgery., Study Design: From 1991 to 1994, 174 of 266 carotid endarterectomy patients underwent preoperative DMS. The ability of clinical factors and DMS to predict postoperative cardiac morbidity was assessed retrospectively in a nonrandomized fashion., Results: Forty-seven adverse cardiac events (deaths = 0, myocardial infarction (MI) = 4, congestive heart failure (CHF) = 9, angina = 7, and new dysrhythmias = 27) occurred in 38 (14.3 percent) of 266 patients. Results of DMS were 73 percent normal, 10.3 percent fixed defect, and 16.7 percent reversible defect examinations. Sensitivity and specificity of DMS was 32 and 74 percent for total cardiac morbidity, and 50 and 74 percent for MI. The positive predictive value of DMS for MI, dysrhythmias, CHF, angina, and all cardiac events was 4, 11, 9, zero, and 23 percent, respectively. Negative predictive values were 98, 91, 98, 95, and 82 percent, respectively. Preoperative histories of MI and chest pain were significant independent predictors of adverse cardiac outcomes (p < 0.05) while age greater than 70 years, smoking, hypertension, diabetes mellitus, preoperative arrhythmias, and DMS were not., Conclusions: Dipyridamole myocardial scintigraphy is an ineffective predictor of adverse cardiac events in patients being evaluated for carotid artery surgery and its routine use is not justified.