Blunt thoracic aortic injury: open or stent graft repair?

BACKGROUND: Despite a lack of level I evidence, endovascular stent grafting is frequently used for the treatment of blunt thoracic aortic injury. The purpose of this study is to compare the outcomes between open and endovascular repair of traumatic rupture of the thoracic aorta. METHODS: This article is based on a single-institution review of all consecutive patients treated for blunt aortic injury at the University of Wisconsin Hospital and Clinics between October 1999 and May 2007. This study was reviewed and approved by the institutional review board. Patients were identified from our Level 1 trauma registry. Inclusion criteria for this study was based on computed tomographic or angiographic evidence of thoracic aortic injury distal to the left subclavian artery. Two groups were identified: patients who underwent open repair (OR) and, patients who underwent endovascular repair (ER). Patient demographics, mechanism of injury, Injury Severity Score, associated injuries, comorbid conditions, intraoperative findings, postoperative complications, and duration of hospital stay were analyzed. Data regarding these patients and their injuries were retrieved from our trauma registry as well as chart review and outpatient records. The outcomes from OR and ER were compared using the Fisher exact test. P values less than 0.05 were considered statistically significant. RESULTS: During the 8-year period, 26 consecutive patients were treated for blunt aortic injury (OR = 12 and ER = 14). There were 20 men, and the mean age was 36 years. There were no differences between the groups in the mechanism of injury, Injury Severity Score, or number of associated injuries on initial presentation. On an intent-to-treat basis, the endovascular therapy was technically successful 100% of the time. There was no procedure-related mortality. There was 1 patient, however, in the OR group with presumed recurrent laryngeal nerve palsy. There was no incident of treatment-related paraplegia in either group. The 1-year survival for OR and ER patients was 93% and 92%, respectively. At 1 year, 25% of patients in the OR group and 18% of patients in the ER group required reinterventions. Mean operating room time was 309 minutes for the ERs and 383 minutes for the patients who underwent OR. Intraoperative blood product administration was greater in the OR group (P = .055); there was no difference between the groups, however, in the total blood products administered for a given hospital stay. The mean duration of hospital stay was 13 days for the OR group and 13.9 days for the ER group. CONCLUSION: There were no significant differences with respect to morbidity or mortality between these 2 groups. These data suggest that ER is at least as safe as OR for blunt aortic injury.

Minimal incision aortic surgery.

PURPOSE: In this study we evaluated the clinical and economic impact of minimal incision aortic surgery (MIAS) for treatment of patients with abdominal aortic aneurysms (AAAs) and aortoiliac occlusive disease (AIOD). METHOD: Fifty patients with either AAA (34) or AIOD (16), prospectively treated with the MIAS technique, were compared with 50 patients (40 AAA and 10 AIOD) treated in the same time period with long midline incision and extracavitary small bowel retraction. MIAS was also compared with a cohort of 32 patients with AAA treated by means of endoaortic stent-grafts. Outcomes and cost (based on metric mean length of stay) were compared for the open and endoaortic techniques. RESULTS: Patients who experienced no perioperative complications after the MIAS or endovascular repair technique had shorter hospital stays than patients with uncomplicated aortic repairs performed with a traditional long midline abdominal incision (3 days vs 3 days vs. 7.2 days). Hospital stay was also significantly shorter for the less invasive procedures when perioperative complications were included (4.8 days vs. 4.3 days vs 9.3 days). The MIAS and endovascular aortic repair groups had a shorter intensive care unit stay (< or = 1.0 day) and a quicker return to general dietary feeding (2.5 days) than patients treated with standard open repair (1.8 days, 4.7 days). The overall morbidity for the MIAS technique (14%) and endovascular technique (21%) was not significantly different from standard open repair (24%). The mortality rate for the different treatment groups was equivalent (MIAS, 2%; endovascular repair, 3%; standard repair, 2%). The MIAS was more cost-efficient than standard open repair ($12,585 vs $18,445) because of shorter intensive care unit and hospital stay and was more cost-efficient than endoaortic repair ($12,585 vs $32,040) because of reduced, direct intraoperative costs. CONCLUSIONS: MIAS is as safe as standard open or endovascular repair in the treatment of AAA and AIOD. MIAS is more cost-efficient than standard open or endoaortic repair.

Visceral artery aneurysm rupture.

PURPOSE: Aneurysms of the visceral arteries are infrequently encountered. Many are found incidentally and are thought to have a benign outcome. To better characterize these lesions and their clinical course, we reviewed our experience with visceral artery aneurysms (VAAs) at a single institution. METHODS: A retrospective analysis of all VAAs diagnosed at our institution over the past 10 years was performed. The presentation, management, and outcome of therapy was examined for each patient. RESULTS: Thirty-four VAAs in 26 patients were diagnosed over the past 10 years. Four patients had multiple VAAs: splenic (17), hepatic (7), celiac (3), superior mesenteric (2), gastroduodenal (2), pancreaticoduodenal (1), right gastric (1), ileal (1) artery aneurysms. Associated aneurysms were found in 31% of patients and involved the thoracic aorta (3 patients), abdominal aorta (4 patients), renal arteries (2 patients), iliac artery (3 patients), lower extremity (1 patient), and intracranium (1 patient). In 15 patients (58%), VAAs were detected before rupture by chance or because abdominal symptoms resulted in diagnostic evaluation. Eight of these underwent elective surgery, and there were no deaths. Of those 15 patients with known VAAs, one patient died of rupture and hemorrhage from an untreated splenic artery aneurysm. Eleven patients (42%) presented unexpectedly with rupture, and two died despite prompt surgical treatment. The mortality rate in patients who had ruptured VAAs was 25%, including those who presented with ruptured aneurysms and those observed whose aneurysms eventually ruptured. CONCLUSIONS: Aneurysms of the visceral arteries are rare but important vascular lesions. Associated aneurysms are common. Because of the risk of rupture, often with a fatal outcome, an aggressive approach to the treatment of VAA is essential.

Less invasive aortic surgery: the minilaparotomy technique.

BACKGROUND: This study evaluated a less invasive technique for exposure of the infrarenal aorta and its impact on the treatment of patients with abdominal aortic aneurysms (AAA) or aortoiliac occlusive disease (AIOD), or both. METHODS: Forty patients with AAA (26), aneurysmal extension into the iliac arteries (6), or AIOD (8) were prospectively selected for minilaparotomy aortic exposure and repair using a small periumbilical midline incision (< or =10 cm); intra-abdominal, nondisplaced retraction of the small bowel; and conventional hand-sewn vascular anastomoses. Perioperative comparisons with a contemporary group of AAA patients treated with long, open midline incision and extracavitary small bowel retraction were made. RESULTS: There was no significant difference between the minilaparotomy and open surgical control groups for operating room time; intraoperative, perioperative morbidity; or mortality. Significant differences were documented between the minilaparotomy and the control group with regard to stay in the intensive care unit (days; 1.0+/-1.2 versus 1.8+/-1.5); return to general diet (days; 3+/-1.3 versus 4.7+/-2.8); and length of stay (days; 4.9+/-1.8 versus 7.3+/- 3.4). CONCLUSIONS: Minilaparotomy exposure is safe and effective for treatment of infrarenal AAA and AIOD. This technique maintains quality outcome while reducing postoperative ileus, hospital stay, and resource utilization.

Preliminary experience with minilaparotomy aortic surgery.

This prospective nonrandomized study assessed clinical outcomes of a minilaparotomy technique (MLT) used for elective graft repair of infrarenal aortic aneurysm (AAA) and/or aortoiliac occlusive disease (AIOD). Twenty-three patients requiring infrarenal AAA or aortofemoral bypass underwent a small periumbilical midline incision, nondisplacement of the small bowel, and a traditional vascular anastomosis. Results from these procedures were compared with those from contemporaneous procedures performed in the standard transabdominal (STA) fashion (n = 21). Age, weight, and comorbid conditions were comparable between groups. Patients requiring concomitant renal, mesenteric, or infrainguinal revascularization were excluded. Operating time, length of stay in the intensive care unit (ICU), number of oral feeding times, and length of hospital stay were recorded. There were no significant differences in age, operative time, or aneurysm size between the MLT and STA groups. With the MLT then were significant decreases in ICU stay (1 vs. 1.8 days), length of time to return to a general diet (3 vs. 4.7 days), and length of stay (4.9 vs. 7.3 days.) Morbidity and mortality were not statistically different between groups. Patients undergoing the MLT have reduced ICU and hospital stay, and decreased post operative ileus. The MLT does not increase operating room costs or require expensive laparoscopic equipment or the extended postoperative radiographic surveillance needed after endovascular repair.

Comparison of treatment plans for lower extremity arterial occlusive disease made with electrocardiography-triggered two-dimensional time-of-flight magnetic resonance angiography and digital subtraction angiography.

BACKGROUND: The purpose of the study was to determine whether preoperative treatment plans for patients with lower extremity ischemia can be made with electrocardiography (EKG)-triggered two-dimensional (2D) time-of-flight (TOF) magnetic resonance angiography (MRA) as accurately as digital subtraction angiography (DSA). METHODS: Forty patients were prospectively evaluated with the combination of EKG-triggered 2D TOF MRA, DSA, and pulse volume recordings. Blinded reviewers graded arterial segments for disease severity. Accuracy of separate MRA- and DSA-based treatment plans was compared with the procedures performed based on all available information. RESULTS: There was an 86% exact match between MRA- and DSA-based plans (92% MRA and 94% DSA accuracy). The MRA-based plan accurately predicted 90% of suprainguinal and 95% of infrainguinal procedures, whereas the DSA-based plan accurately predicted 100% of suprainguinal and 85% of infrainguinal procedures. Two-year primary patency was 83% for all procedures. Radiologists' review of disease severity resulted in a mean exact correlation between studies of 81% (kappa = 0.64). The agreement between radiologists interpreting the MRA was 84% (kappa = 0.7) compared with 82% (kappa = 0.66) for the DSA. CONCLUSIONS: MRA- and DSA-based preoperative management plans were of comparable efficacy. Significant interobserver variability was seen with the interpretations of both preoperative studies. EKG-triggered 2D TOF MRA can be used to plan arterial reconstructions; however, all patients require arterial pressure measurements prior to suprainguinal repair and confirmatory intraoperative angiography during infrainguinal revascularization.

Macrophage depletion alters vein graft intimal hyperplasia.

BACKGROUND: The principal cause of vein graft failure is intimal hyperplasia (IH); however, its etiology remains unclear. In a rat model of vein graft IH we have observed prolonged transmural macrophage infiltration, leading us to hypothesize that these cells regulate IH. To test this, we used liposome-encapsulated dichloromethylene bisphosphonate (L-Cl2MBP) to deplete rat macrophages and observed the effects on IH. METHODS: Epigastric vein-to-femoral artery grafts were microsurgically placed in male Lewis rats that had been intravenously injected with L-Cl2MBP, phosphate-buffered saline solution liposomes, or phosphate-buffered saline solution alone 2 days before surgery. Several animals in each group received a second equivalent dose at 2 weeks. Grafts, contralateral epigastric veins, spleens, and livers were harvested at 1, 2, and 4 weeks for histologic examination, immunohistochemistry, and transmission electron microscopy. RESULTS: In the L-Cl2MBP-treated animals splenic and hepatic macrophages were greatly reduced, confirming the efficacy of the agent. At 1 to 2 weeks graft macrophages were significantly decreased, and there was a trend toward decreased IH. At 4 weeks macrophage numbers were normal and IH development had resumed. In contrast, the 4-week grafts treated with 2 doses of L-Cl2MBP had fewer macrophages and displayed severely attenuated IH. CONCLUSIONS: The results indicate a suppression of IH as macrophages are depleted, with a resumption of the process as macrophages repopulate the graft.

Cardiac function is a risk factor for paralysis in thoracoabdominal aortic replacement.

PURPOSE: We studied factors that influence paralysis risk, renal function, and mortality in thoracoabdominal aortic replacement. METHODS: We prospectively collected preoperative demographic and intraoperative physiologic data and used univariate and multivariate analyses to correlate this data with risk factors for paralysis. A mathematical model of paraplegia risk was used to study the efficacy of paraplegia reduction strategies. We analyzed preoperative and operative factors for paralysis risk, renal function, and mortality for 217 consecutive patients surgically treated from 1984 through 1996 for 176 thoracoabdominal and 41 thoracic aneurysms at the University of Wisconsin Hospital and Clinics. No patient had intercostal reimplantation or assisted circulation. One hundred fifty patients (group A) received cerebrospinal fluid drainage (CSFD) and low-dose naloxone (1 microg/kg/hour) as adjuncts to reduce the risk of paralysis. Sixty-seven patients (group B) did not receive CSFD and naloxone. RESULTS: Seventeen deficits occurred in 205 surviving patients: 5 of the 147 in group A (expected deficits = 31) and 12 of the 58 in group B (expected deficits = 13) (p < 0.001). In a multivariate logistic regression model, acute presentation, Crawford type 2 aneurysm, group B membership, and a decrease in cardiac index with aortic occlusion remained significant risk factors for deficit (p < 0.0001). By odds ratio analysis, group A patients had 1/40th the risk of paralysis of group B. The only significant predictor of postoperative renal function was the preoperative creatinine level (p < 0.0001); renal revascularization significantly improved renal function. The mortality rate was 1.6% (2) for patients undergoing elective treatment and 21% (19) for patients who had acute presentations. Acute presentation, age, and the preoperative creatinine level were found to be significant factors for operative mortality in a logistic regression model (p < 0.001) and defined a group at high risk for death. CONCLUSIONS: CSFD and low-dose naloxone significantly reduce the paralysis risk associated with thoracoabdominal aortic replacement. A decrease in the cardiac index with aortic occlusion is a previously unreported variable that defines a subset of patients at higher risk for paralysis.

Management of the complications of long-term venous access.

The increasing use of permanent venous access devices and peripherally inserted central catheters has dramatically altered how we care for patients with a variety of illnesses. The development of complications either at the time of catheter insertion or with prolonged use may result in limited durability of the device, decreased cost-effectiveness, and significant patient morbidity or mortality. Our purpose is to review for the clinician the common complications associated with permanent venous access devices (PVADs) and peripherally inserted central catheters (PICCs). Most PVAD complications occurring at the time of catheter insertion can be avoided by returning to the venous cut-down technique. The most common cause for PVAD removal before the completion of therapy is catheter-related infection, whereas mechanical device failures result in most premature removals of PICCs. Catheter-related subclavian and axillary vein thromboses are not benign but are associated with up to a 12% incidence of pulmonary embolism. Future prospective investigations are needed to identify techniques to prevent, or better manage, the major long-term complications of PVADs and PICCs.

Monocyte chemotactic protein-1 expression is associated with the development of vein graft intimal hyperplasia.

Infiltration of immunologically active cells into vein grafts is concomitant with the development of intimal hyperplasia (IH) and often leads to obliterative stenosis and graft failure. Previous work has demonstrated the prolonged presence of monocytes and macrophages in vein grafts. The stimuli attracting these macrophages remain unidentified. Monocyte chemotactic protein-1 (MCP-1), a potent and specific chemokine for monocytes/macrophages, is secreted by smooth muscle cells, endothelial cells, fibroblasts, and leukocytes, all of which are present in grafted veins. In this study, we examined the temporal profile of MCP-1 gene expression in rat vein grafts by using reverse transcription-polymerase chain reaction (PCR) and immunohistochemistry. Epigastric vein-to-femoral artery bypass grafts were microsurgically placed and harvested at various time points after grafting. Histological analysis confirmed the consistent development of IH. PCR was performed and relative levels of MCP-1 quantified by autoradiography. Our results show that MCP-1 mRNA levels increased 28-fold by 4 hours after grafting and up to 117-fold by 1 week. After this time MCP-1 mRNA levels decreased; nonetheless, even at 8 weeks after grafting, message levels remained elevated 7-fold above baseline. Immunoreactive MCP-1 protein and ED1+ macrophages were detected at all time points; the degree of immunostaining correlated with MCP-1 mRNA levels. Our results support the hypothesis that upregulation of MCP-1 gene expression in vein grafts results in the recruitment of monocytes and tissue macrophages to the vein wall, which leads to IH. The correlation between monocyte/ macrophage infiltration and IH suggests a critical role for these cells in IH development.

An ultrastructural study of progressive intimal hyperplasia in rat vein grafts.

PURPOSE: Intimal hyperplasia (IH) poses the greatest challenge for vein graft success. This fibroproliferative disorder causes obliterative stenosis and frequent graft occlusion. Although its causes remain poorly understood, it has been proposed that IH begins as a wound-healing response that cascades into a chronic state of unchecked proliferation. In this ultrastructural study, IH development and concomitant cell changes were evaluated in rat vein grafts. METHODS: Epigastric vein-to-femoral artery grafts were placed in Lewis rats using standard microsurgical techniques. At various time points, grafts were harvested and processed for transmission electron microscopic, histologic, and immunohistochemical analyses. The proximal region, which displayed the most marked IH, was assessed for ultrastructural changes. RESULTS: Our findings showed: (1) regeneration of the damaged endothelium by cells displaying an activated appearance; (2) early and complete smooth muscle cell death, with subsequent replacement by myofibroblastic cells; (3) extensive and sustained graft infiltration by monocytes/macrophages; and (4) intramural fibrin deposition. CONCLUSIONS: The rat vein graft wall was substantially altered after implantation into the arterial circulation. During and after IH development, the cells in the graft did not resemble cells that are present in the nongrafted epigastric vein. Marked cell death, mononuclear cell infiltration, and the presence of myofibroblastic cells suggest a state of aberrant wound healing.

Late renal function in patients undergoing renal revascularization for control of hypertension and/or renal preservation.

Long-term outcome was studied in 233 patients who had undergone renal artery revascularization (51 with balloon angioplasty, 182 with surgery) between 1976 and 1992. Patients (excluding renal transplants) were treated for renal vascular hypertension without or with renal insufficiency (serum creatinine > 1.6 mg/dl. All patients still alive (n = 188) were contacted to determine current blood pressure, medications, serum creatinine, and subsequent significant medical events. In patients who had died the cause of death was determined and renal function status at the time of death noted from medical records. Some follow-up information was obtained on all 233 patients; follow-up serum creatinine data were obtained in 193 (82.8%) patients. Some 24 patients (10.3%) became dialysis-dependent. Using a multiple logistic regression analysis only, preoperative creatinine maintained significance (P < 0.001) for increased dialysis risk. There was no statistically significant association of dialysis for type of revascularization (percutaneous transluminal angioplasty, autogenous artery, saphenous vein, endarterectomy or synthetic material), simultaneous or previous aortic or other vascular surgery (carotid endarterectomy, femoropopliteal bypass, etc.), pathology (atherosclerosis or fibromuscular dysplasia), number of renal arteries stenosed or treated, length of follow-up, age, coronary artery disease, congestive heart failure, stroke, chronic lung disease or type II diabetes. It is concluded that, in patients with renal artery stenosis, the timing of renal artery revascularization relative to the level of renal function is the most important determinant for long-term renal salvage.

Use of magnetic resonance angiography for the preoperative evaluation of patients with infrainguinal arterial occlusive disease.

PURPOSE: This study was designed to determine whether magnetic resonance angiography (MRA) will allow preoperative management decisions without the need for contrast arteriography in patients with lower extremity ischemia caused by infrainguinal arterial occlusive disease. METHODS: Forty-five patients with lower extremity ischemia in 50 limbs were evaluated by both two-dimensional time-of-flight MRA and intraarterial digital subtraction angiography (DSA) between February 1992 and June 1995. Independent management plans were based on clinical presentation, pulse volume recordings, and separate reviews of the MRA and DSA. RESULTS: Of 50 limbs, 23 required arterial bypass, 19 percutaneous transluminal angioplasty, 5 patch angioplasty, and 3 amputation. MRA and DSA correlated exactly in 89.5% of infrainguinal arterial segments, whereas interpretations disagreed in 10.5% of arterial segments. Mismatches that had an influence on patient treatment decisions occurred in only 8 (2.3%) of 352 arterial segments. Independent MRA- and DSA-based revascularization plans agreed in 45 (90%) extremities. MRA predicted the level of arterial reconstruction in all 23 limbs that required arterial bypass. MRA identified focal stenoses amenable to percutaneous transluminal angioplasty in 18 (94.7%) of the 19 limbs that ultimately underwent percutaneous transluminal angioplasty. A strategy of preoperative planning by MRA with confirmatory intraoperative arteriography would represent a 31% cost savings per patient at our institution while eliminating the morbidity of preoperative DSA. CONCLUSIONS: When used in combination with the patient's physical examination and segmental limb pressures with plethysmography, MRA is sufficient for planning infrainguinal arterial bypass procedures and selecting patients for percutaneous transluminal angioplasty.

The temporal relationship between the development of vein graft intimal hyperplasia and growth factor gene expression.

PURPOSE: Intimal hyperplasia is a common cause of obstructive stenosis after arterial reconstructive procedures. It has been postulated that growth factors elaborated by vascular wall cells regulate fibroproliferative changes that can cause graft failure. This study characterizes transforming growth factor beta-1 (TGF-beta 1) and platelet-derived growth factor-A chain (PDGF-A) mRNA transcript profiles and their temporal relationship to the development of intimal hyperplasia in vein grafts. METHODS: Epigastric vein-to-common femoral artery interposition grafts were performed in male Lewis rats (350 to 450 gm) with standard microsurgical techniques. Grafts were harvested at 1 and 4 hours, 1 and 4 days, and 1 and 2 weeks (n = 5/time). Graft RNA was extracted, reverse-transcribed, and amplified by polymerase chain reaction with sense/antisense primers for TGF-beta 1 and PDGF-A (30 cycles). Polymerase chain reaction fragments were confirmed by Southern hybridization. RESULTS: Variable induction of TFG-beta 1 gene transcription was evident in vein grafts at 1 and 4 hours, with prominent mRNA expression from 1 day to 2 weeks. PDGF-A mRNA was detected in ungrafted control veins but was downregulated at 1 hour and absent at 4 hours after grafting. PDGF-A transcription was upregulated by 1 day, with prominent expression from 4 days to 1 week. Early loss of PDGF-A mRNA correlated with the early denudation of the endothelium, whereas upregulation by 4 days was preceded by TGF-beta 1 mRNA expression. CONCLUSIONS: Upregulation of TGF-beta 1 and PDGF-A mRNA expression is detected in vein grafts before the development of a quantifiable neointima, which occurs by 2 weeks in our model. This suggests a role for these growth factors in the development of vein graft intimal hyperplasia.

Thrombolysis versus surgery as the initial management for native artery occlusion: efficacy, safety, and cost.

BACKGROUND: A controversy has evolved as to which therapy, thrombolysis or thromboembolectomy, represents the optimal initial treatment for acute native artery occlusion. METHODS: Forty-eight cases of acute class I or II limb ischemia caused by native artery occlusion were retrospectively analyzed between 1988 and 1993. Nineteen of the patients were initially treated with thrombolysis (group 1), and 29 underwent thromboembolectomy (group 2). RESULTS: Initial clinical improvement was seen in 11 (57.9%) of 19 extremities in group 1, with complete clot resolution in 21%, partial lysis in 47.4%, and no angiographic improvement in 31.6%. Significantly superior results were achieved in group 2; 28 (97%) of 29 limbs showed clinical improvement after initial surgical therapy (p = 0.001). Limb salvage was 88.2% in group 1 and 96.6% in group 2 (p = 0.5). Adjunctive procedures for limb salvage were necessary in 10 (52.6%) of 19 limbs in group 1 compared with only five (17.2%) of 29 limbs in group 2 (p = 0.013). Perioperative mortality was 10.5% and 10.3% (p = 1.0), whereas major postoperative complications occurred in 63.2% and 37% of patients in groups 1 and 2, respectively (p = 0.14). Hospital and professional patient charges were analyzed for the 12 most recent patients from each group. Total mean charges per patient were higher in group 1 ($45,171) than in group 2 ($24,898) (p = 0.046). CONCLUSIONS: Patients initially treated surgically achieved better immediate clinical results with significant cost savings and without significant differences in morbidity, mortality, or limb salvage compared with patients treated initially by thrombolysis.

Vein graft intimal hyperplasia: leukocytes and cytokine gene expression.

BACKGROUND: Intimal hyperplasia (IH), a cause of early graft failure, may be regulated by leukocyte-elaborated cytokines. We investigated leukocyte infiltration and cytokine gene expression in vein grafts. METHODS: Epigastric vein to femoral artery grafts were performed in Lewis rats and harvested on day 4 and weeks 1, 2, 4, 8, and 12. Neointimal areas were measured by computerized planimetry. Immunoperoxidase staining identified for macrophages, CD4+, CD8+, and major histocompatibility complex class II+ cells. Graft RNA was used in reversetranscription-polymerase chain reaction with interleukin (IL)-1 alpha, IL-2R, monocyte chemoattractant protein-1, and transforming growth factor-beta primers. RESULTS: IH was measurable at 2 weeks; the perianastomotic regions displayed greater IH than the midgraft (p < 0.05). MANOVA indicated strong location (p = 0.0001) and time (p = 0.0009) effects. Immunocytochemistry showed inflammatory infiltrates from 4 days to 4 major histocompatibility complex class II+ and primarily monocyte/macrophages, with less frequent T lymphocytes (CD4+ > CD8+). IL-1 alpha messenger RNA is expressed early, disappearing after 4 weeks. Monocyte chemoattracta t protein-1 mRNA is constitutively expressed, with up-regulation at 4 days to 4 weeks. IL-2R mRNA levels fluctuate; transforming growth factor-beta is always expressed, peaking at 4 days to 4 weeks. CONCLUSIONS: Gene expression of cytokines thought to modulate IH is up-regulated early in vein grafts. This coincides with graft infiltration by activated leukocytes before and during the development of IH.

Combined use of cerebral spinal fluid drainage and naloxone reduces the risk of paraplegia in thoracoabdominal aneurysm repair.

PURPOSE: This report summarizes our experience with the use of cerebral spinal fluid drainage (CSFD) and naloxone for prevention of postoperative neurologic deficit (paraplegia or paraparesis). METHODS: We reviewed 110 consecutive patients with 86 thoracoabdominal aneurysms and 24 thoracic aneurysms. The status of 47 patients (43%) was acute (rupture or dissection), and the status of 52 (47%) was Crawford type I or II. None of the patients had intercostal artery reimplantation. There were two patient groups for analysis of neurologic deficit risk. Group A (61 patients) received naloxone and CSFD, and group B (49 patients) did not. RESULTS: One deficit occurred in group A and 11 deficits occurred in group B (p = 0.001). By multiple logistic regression analysis, the variables acute status, Crawford type II, or group B classification were significant factors for deficit risk. Use of the same logistic regression analysis on the subgroup of 47 patients with acute aneurysms and 33 patients with Crawford type 2 aneurysms confirmed the protective effect of combined CSFD and naloxone (group A) and that clinical presentation and extent of aorta replaced are the primary risk factors for development of deficit. To test this conclusion we developed a highly predictive model (correlation coefficient 0.997 with 16 series of thoracoabdominal aneurysms) for neurologic deficit. We applied our data to this model. Group B had the predicted number of deficits, and group A had substantially fewer deficits than predicted. CONCLUSIONS: We conclude that the combined use of CSFD and naloxone offers significant protection from neurologic deficits in patients undergoing thoracoabdominal and thoracic aortic replacement.

Magnetic resonance angiography and duplex imaging: noninvasive tests for selecting symptomatic carotid endarterectomy candidates.

BACKGROUND: This report describes our experience with the use of duplex imaging and magnetic resonance angiography (MRA) in the diagnosis and management of 70 patients with symptomatic carotid artery disease. Prospective evaluation of our first 30 patients showed that duplex imaging and MRA accurately correlated with conventional cerebral arteriograms (XRA) in patients with symptoms with greater than 70% ipsilateral carotid artery stenoses. In MRA versus XRA accuracy was 94%, sensitivity 100%, and specificity 93%. With duplex scanning versus XRA accuracy was 88%, sensitivity 93%, and specificity 93%. METHODS: We are now performing carotid endarterectomy on patients with symptoms without preoperative XRA when there is exact correlation between duplex imaging and MRA. Patients must have focal hemispheric symptoms, ipsilateral duplex peak systolic velocity greater than 2 m/sec, and high-quality MRA imaging of the carotid vessels. RESULTS: We have prospectively entered 40 patients for preoperative evaluation with duplex imaging and MRA. High-quality MRA and duplex studies were obtained in 35 patients (88%). XRA was required in the remaining five patients (12%) because of discrepancies between duplex scanning and MRA. Endarterectomy was performed without morbidity or death. Combined use of duplex scanning and MRA eliminated XRA in 35 cases and created a net savings of more than $125,000. CONCLUSIONS: Our experience suggests that preoperative XRA may not be necessary when duplex imaging and MRA confirm the presence of severe extracranial disease.

Combined use of duplex imaging and magnetic resonance angiography for evaluation of patients with symptomatic ipsilateral high-grade carotid stenosis.

PURPOSE: Advances in cerebral vascular imaging suggest that patients with critical levels of carotid artery stenosis (> 70%) who have symptoms can be identified accurately and necessary information about the intracranial and extracranial circulation obtained before surgery without conventional angiography. We have used carotid duplex imaging in combination with magnetic resonance angiography (MRA) to evaluate 20 patients with symptomatic ipsilateral high-grade carotid stenosis. METHODS: All patients underwent CT and magnetic resonance imaging brain scans, as well as MRA and conventional arteriography of the cerebral circulation. Magnetic resonance angiograms were obtained with two-dimensional phase contrast and time-of-flight techniques. Phase contrast was used for intracranial vascular imaging and for determining qualitative flow velocities and the direction of blood flow in the circle of Willis. Two-dimensional time of flight was used to assess the carotid bifurcations. RESULTS: Twenty patients with symptoms (six with strokes, 11 with transient ischemic attacks, and three with amaurosis fugax) had duplex evidence of high-grade carotid stenoses. Computed tomographic and magnetic resonance brain scans were positive for cerebral infarction in six patients with clinical strokes. Comparison of MRA with conventional angiography was 91% accurate for high-grade stenoses and occlusions (sensitivity 100% and specificity 90% for stenosis; sensitivity/specificity was 100% for complete occlusion). Comparison of duplex imaging with conventional angiography demonstrated 86% accuracy for detection of severe stenosis or occlusion (sensitivity 94% and specificity 89% for stenosis; sensitivity and specificity were 100% for complete occlusion). CONCLUSIONS: This study suggests that combined use of MRA and duplex imaging is accurate for detection and evaluation of high-grade carotid stenoses in patients with symptoms.

Axillopopliteal bypass for limb salvage.

Forty-one axillopopliteal bypass grafts have been placed in 30 patients for limb salvage in the past 12 years. The mean patient age was 65.6 years; 8 were women; 19 smoked; and six had diabetes. Sixteen grafts were straight axillopopliteal bypass grafts, and 25 were sequential axillopopliteal bypass grafts. Cumulative life-table primary patency rates at 1, 2, and 3 years were 70%, 56%, and 43%, respectively; secondary patency rates were 73%, 57%, and 50%, respectively. Corresponding limb salvage rates were 86%, 69%, and 69%, respectively. Ringed polytetrafluoroethylene (PTFE) graft patency at 3 years was 61% versus 40% for unsupported PTFE grafts (p = 0.35). Ringed PTFE axillofemoral grafts with sequential femoropopliteal saphenous vein grafts had a 3-year patency of 67%. Graft patency was restored in 25% of occluded grafts by thrombectomy and in 80% of occluded grafts by thrombectomy with graft revision (p = 0.21). Cumulative 3-year patient survival was 48%. The 30-day operative mortality rate was 20%; patients operated on for graft infection had a 30-day operative mortality rate of 36%. The data support the use of axillopopliteal bypass for limb salvage when standard revascularization techniques are contraindicated. Long-term patency is enhanced by use of externally supported PTFE and sequential femoropopliteal saphenous vein.