Benchmarking a Center of Excellence in Vascular Surgery: Using Acute Physiology and Chronic Health Evaluation II to Validate Outcomes in a Tertiary Care Institute.

OBJECTIVE: The Society of Vascular Surgery (SVS) has made it a top priority to implement verification of vascular "centers of excellence". Our institutional aortic network was established in 2008 in order to standardize care of patients with suspected acute aortic pathology. The implementation and success of this program has been previously reported. We sought to use our experience as a benchmark for which to develop prognostic modeling to quantify clinical status upon admission and help predict outcomes. Our objective was to validate the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system using a cohort of aortic emergencies transferred by an organized transfer network. METHOD: This was a retrospective, single institution review of patients transferred through an institutional aortic network for acute aortic pathology from 2017-2018. Demographics, comorbidities, aortic diagnosis, APACHE II score, as well as 30-day mortality were recorded. Associations with 30-day mortality were evaluated using two-sample t-tests, ANOVA models, Pearson chi-square tests and Fisher exact tests. Receiver operating characteristic (ROC) curves were fit overall and by pathology to predict 30-day mortality by Apache II total score. RESULTS: There were 395 consecutive transfers were identified. The mean age was 64.7 years. Diagnoses included Type A Dissection (n = 134), Type B (n = 81), Aortic Aneurysm (n = 122), and PAU/IMH (n = 27). Mean APACHE II score on arrival was 12. Overall there were 53 deaths (13.4%) in the cohort. Patients that died had significantly higher Apache II total scores (11.3 vs 16.5, P < .001). The area under the receiver operator characteristic (ROC) curve (AUC) was .66 for the full cohort, indicating a poor clinical prediction test. CONCLUSION: APACHE II score is a poor predictor of 30-day mortality in a large transfer network accepting all aortic emergencies. The authors believe further refining a prognostic model for diverse population will not only help in predicting outcomes but to objectively quantify illness severity in order to have a basis for comparison among institutions and verification of "centers of excellence".

Abdominal aortic aneurysm repair in high-risk and elderly patients.

Elective open repair of abdominal aortic aneurysm (AAA) is a proven surgical therapy with acceptable rates of perioperative mortality. Open AAA repair in elderly and high-risk patients, however, carries a significantly greater risk of surgical mortality and perioperative complications. Given the steady increase of life expectancy in developed nations, assessment of surgical outcomes and clarification of the role of emerging therapies in the aging population are of significant interest to the vascular surgeon. Selection of treatment options for these patients must be based on an individual approach, and assessment of outcomes must include more subtle parameters, such as quality of life, in addition to operative survival. Recent studies assessing the applicability of endoluminal graft repair in the elderly demonstrate that this avenue of treatment may offer substantial benefit to selected patients. We review the historical data regarding operative aneurysm repair in the high-risk and elderly population, and examine the impact of endoluminal therapy of AAAs in these challenging patients.

Endovascular abdominal aortic aneurysm repair in 144 patients: correlation of aneurysm size, proximal aortic neck length, and procedure-related complications.

PURPOSE: During endovascular abdominal aortic aneurysm (AAA) repair, larger aneurysms often present formidable anatomic challenges to the insertion of the delivery catheter and graft deployment. The authors sought to evaluate whether large-diameter aneurysms and those with short proximal aortic necks might be associated with a higher frequency of insertion-related and short-term complications. MATERIALS AND METHODS: From October 1999 to August 2000, 144 patients underwent elective endovascular graft placement for infrarenal AAA disease at the authors' institution. These patients were treated with use of the AneuRx bifurcated endoprosthesis. AAA size (maximum aneurysm diameter) and proximal aortic neck length were compared to estimated blood loss, operative time, accuracy of graft placement, presence of endoleak, intraoperative and postoperative complications (such as limb occlusion or vascular injury), length of hospital stay, and mortality. Statistical methods included correlation analysis and logistic regression. RESULTS: There were 121 men and 23 women whose aneurysms ranged in size from 3 cm to 9.8 cm (mean, 5.6 cm; 95% CI, 5.4-5.8 cm). Endograft insertion was successful in all cases. There were three deaths within 30 days (2.1%) and seven deaths overall (4.9%). There were 43 intraoperative complications (29.9%) in 31 patients (21.5%), most of them minor. Patients with major intraoperative complications had significantly longer procedure times than those without complications (337 vs. 149 min; P <.0001). In the postoperative period (within 30 days), 31 complications (21.5%) occurred in 28 patients (19.4%), again most of them minor. AAA size was unrelated in any way to the rate of complications, but short proximal aortic neck length was associated with more serious intraoperative and postoperative complications (P =.0404 and P =.0230, respectively), and decreased 30-day and overall survival (P =.0240 and P =.0152, respectively). CONCLUSIONS: Endovascular repair of large AAAs can be challenging; however, the size of the AAA does not influence the rate of complications. A short proximal aortic neck is the only significant risk factor for more serious complications.

Use of aortic cuffs to exclude iliac artery aneurysms during AneuRx stent-graft placement: initial experience.

PURPOSE: As many as 39% of patients who undergo aortic endografting for abdominal aortic aneurysm disease will have ectasia of the iliac arteries that will require intervention. Coil embolization of the internal iliac artery and extension of the graft to the external iliac artery is one solution to this problem. However, 19%-41% of these patients experience buttock claudication, which may be permanent, after unilateral embolization. The authors examined an alternative: the use of larger-sized aortic cuffs to seal the iliac limb. Outcomes and short-term results are presented in this article. MATERIALS AND METHODS: From October 1999 to August 2000, 144 AneuRx stent-grafts were placed at the authors' institution. Among the population receiving stent-grafts, 14 patients had 15 aortic cuffs placed across the distal iliac graft limbs to seal them and preserve flow to the internal iliac artery. One patient had bilateral cuffs placed. Five patients had embolization of the contralateral internal iliac artery because of bilateral disease. Patients were followed with computed tomography (CT) at 1, 6, and 12 months to evaluate for endoleaks. RESULTS: One- and 6-month endoleak rates, determined from only those patients with follow-up CT, were 0% and 10%, respectively. One type II endoleak was first discovered 9 months after graft placement. It sealed spontaneously at 15-month follow-up. One patient among the five who had internal iliac artery embolization had claudication. Mean CT follow-up was 7.8 months (range, 1-15). One patient declined CT but was alive and well 11 months after endografting. One patient moved across the country and declined follow-up. CONCLUSION: Placement of aortic cuffs in dilated iliac arteries can preserve flow to the ipsilateral internal iliac artery and provide an adequate seal. Additionally, the option of later treatment is maintained. Patients with bilateral iliac ectasia can undergo stent-graft placement without bilateral internal iliac artery embolization. Longer-term follow-up in larger numbers of patients will be important to determine the ultimate durability of this technique.

Novel MRI contrast agent for molecular imaging of fibrin: implications for detecting vulnerable plaques.

BACKGROUND: Molecular imaging of thrombus within fissures of vulnerable atherosclerotic plaques requires sensitive detection of a robust thrombus-specific contrast agent. In this study, we report the development and characterization of a novel ligand-targeted paramagnetic molecular imaging agent with high avidity for fibrin and the potential to sensitively detect active vulnerable plaques. METHODS AND RESULTS: The nanoparticles were formulated with 2.5 to 50 mol% Gd-DTPA-BOA, which corresponds to >50 000 Gd(3+) atoms/particle. Paramagnetic nanoparticles were characterized in vitro and evaluated in vivo. In contradistinction to traditional blood-pool agents, T1 relaxation rate as a function of paramagnetic nanoparticle number was increased monotonically with Gd-DTPA concentration from 0.18 mL. s(-1). pmol(-1) (10% Gd-DTPA nanoparticles) to 0.54 mL. s(-1). pmol(-1) for the 40 mol% Gd-DTPA formulations. Fibrin clots targeted in vitro with paramagnetic nanoparticles presented a highly detectable, homogeneous T1-weighted contrast enhancement that improved with increasing gadolinium level (0, 2.5, and 20 mol% Gd). Higher-resolution scans and scanning electron microscopy revealed that the nanoparticles were present as a thin layer over the clot surface. In vivo contrast enhancement under open-circulation conditions was assessed in dogs. The contrast-to-noise ratio between the targeted clot (20 mol% Gd-DTPA nanoparticles) and blood was approximately 118+/-21, and that between the targeted clot and the control clot was 131+/-37. CONCLUSIONS: These results suggest that molecular imaging of fibrin-targeted paramagnetic nanoparticles can provide sensitive detection and localization of fibrin and may allow early, direct identification of vulnerable plaques, leading to early therapeutic decisions.

Endoluminal graft repair for abdominal aortic aneurysms in high-risk patients and octogenarians: is it better than open repair?

OBJECTIVE: To analyze the short-term and midterm results of open and endoluminal repair of abdominal aortic aneurysms (AAA) in a large single-center series and specifically in octogenarians. METHODS: Between January 1997 and October 2000, 470 consecutive patients underwent elective repair of AAA. Conventional open repair (COR) was performed in 210 patients and endoluminal graft (ELG) repair in 260 patients. Ninety of the patients were 80 years of age or older; of these, 38 underwent COR and 52 ELG repair. RESULTS: Patient characteristics and risk factors were similar for both the entire series and the subgroup of patients 80 years or older. The overall complication rate was reduced by 70% or more in the ELG versus the COR groups. The postoperative death rate was similar for the COR and ELG groups in the entire series and lower (but not significantly) in the ELG 80 years or older subgroup versus the COR group. The 36-month rates of freedom from endoleaks, surgical conversion, and secondary intervention were 81%, 98.2%, and 88%, respectively. CONCLUSION: The short-term and midterm results of AAA repair by COR or ELG are similar. The death rate associated with this new technique is low and comparable, whereas the complication rate associated with COR in all patients and those 80 years or older in particular is greater and more serious than ELG repair. Long-term results will establish the role of ELG repair of AAA, especially in elderly and high-risk patients.

Increased expression of HDJ-2 (hsp40) in carotid artery atherosclerosis: a novel heat shock protein associated with luminal stenosis and plaque ulceration.

PURPOSE: Evidence suggests that both humoral and cellular autoimmune processes directed toward heat shock proteins (hsp) contribute to the pathogenesis of atherosclerosis. We characterized a human hsp distinct from those previously characterized in atherosclerotic lesions, termed HDJ-2. METHODS: To determine the role of HDJ-2 in atherosclerosis, we compared the level of HDJ-2 mRNA expression with the level of hsp60 and hsp70 mRNA expression in 26 carotid endarterectomy specimens and 17 normal arteries. The level of expression of HDJ-2 mRNA was also correlated to the presence of plaque ulceration and the degree of luminal stenosis associated with the lesion. RESULTS: The expression of HDJ-2 and hsp70 was significantly higher in carotid artery plaques as compared with normal arteries: HDJ-2, 6.7 +/- 1.6 vs 0.1 +/- 0.04, (P =.001); hsp70, 9.5 +/- 0.9 vs 3.7 +/- 0.8, (P =.002). There was no significant difference in hsp60 expression between carotid artery plaques and normal arteries (21.0 +/- 0.9 vs 20.6 +/- 0.8, P =.65). Increased HDJ-2 expression in carotid artery plaques was independent of hsp70 (Pearson correlation, r = 0.11; Bartlett chi(2) analysis, P =.71). Within the ulcerated plaque group, there was a correlation between degree of stenosis and high HDJ-2 mRNA expression (r = 0.896, P =.016). However, there was no correlation between degree of stenosis and high HDJ-2 mRNA expression within the nonulcerated plaque group (r = 0.530, P =.076) or within the entire group of patients (r = 0.0085, P =.97). CONCLUSION: These results demonstrate that expression of HDJ-2 is significantly increased in atherosclerotic carotid artery plaques as compared with hsp60 and hsp70 and correlates with luminal stenosis in ulcerated atherosclerotic carotid artery plaques.

Evolution of vascular fellowship training in the new era of endovascular techniques.

PURPOSE: The endovascular technique has revolutionized the treatment of infrarenal abdominal aortic aneurysm (AAA). At our institution, we examined the impact of an endovascular program on the traditional operative training of the vascular fellows in the treatment of infrarenal AAA. METHODS: We examined the records of our vascular fellows' experience from July 1995 to May 2000. We introduced the endovascular treatment for infrarenal AAA in 1995. RESULTS: The fellows have performed increasing numbers of endovascular cases each year, with a predicted number of 124 cases for 1999-2000. However, despite an increase in the overall volume of patients with infrarenal AAA (102 cases in 1998-1999 and a predicted 160 cases in 1999-2000), the trainees will experience a reduction in the number of open AAAs from 61 cases in 1998-1999 to a predicted 36 cases in 1999-2000. However, the volume of open suprarenal AAA has also increased from eight cases in 1998 to 1999 to a predicted 24 cases in 1999-2000. With no significant change in the open aortoiliac occlusive cases from previous years, the current fellows will graduate with a similar volume of open aortic procedures as their predecessors. CONCLUSION: With the recent advances in endovascular technology, our traditional operative approach to the treatment of AAA disease may be lacking in the training of future vascular surgeons. At our institution, although fewer open infrarenal AAA cases were performed, the trainees have maintained the open aortic experience by performing an increased volume of suprarenal AAAs. We have to critically reevaluate and redefine what constitutes adequate vascular fellow experience in the surgical treatment of abdominal aortic aneurysms.

The Hemobahn endoprosthesis: a self-expanding polytetrafluoroethylene-covered endoprosthesis for the treatment of peripheral arterial occlusive disease after balloon angioplasty.

Endoluminal management of occlusive arterial disease has previously been limited to balloon angioplasty, either alone or with stent placement. This article discusses the Hemobahn endoprosthesis, a polytetraflouroethylene-covered nitinol stent graft. The Hemobahn device design characteristics, Food and Drug Administration phase I feasibility trial design and results, phase II pivotal trial design, and single-site phase II trial results are reviewed. The long-term outcomes of patients treated with angioplasty and Hemobahn stent grafting will determine the role of stent grafting in the management of occlusive arterial lesions below the aortic bifurcation.

Accelerated replicative senescence of medial smooth muscle cells derived from abdominal aortic aneurysms compared to the adjacent inferior mesenteric artery.

BACKGROUND: Abdominal aortic aneurysms (AAAs) are associated with aging and atherosclerosis. AAAs arise through a degenerative process characterized in part by depletion of medial smooth muscle cells (SMC), suggesting that generalized aging and SMC senescence represent potential mechanisms contributing to aneurysmal degeneration. It is not yet known whether SMC from AAA tissue exhibit a difference in proliferative capacity compared to SMC from nonaneurysmal vessels or to what extent such differences might be due to aging alone or other patient-specific factors. MATERIALS AND METHODS: Aneurysm wall tissues were obtained from 15 patients undergoing AAA repair. In each case, a segment of the adjacent (nonaneurysmal) inferior mesenteric artery (IMA) from the same patient was used as a control. Paired AAA- and IMA-derived SMC strains were obtained by explant techniques and their proliferative capacities were compared during serial passage in culture. RESULTS: Sustainable SMC cultures were established from all IMA explants but from only 9 of 15 AAAs (P < 0.05). The interval required to achieve primary explant growth was longer for AAAs than IMAs (16.4 +/- 2 vs 6.4 +/- 1 days; P < 0.001), but it was unrelated to patient age, gender, or aneurysm size. AAA-derived SMC appeared larger and rounder than the corresponding IMA-derived SMC, even after repeated passage in culture, and their maximal proliferation was reduced by 44.2 +/- 8% (n = 5 pairs, P < 0.05). Serum-stimulated [(3)H]thymidine uptake in AAA-derived SMC was also reduced by 54.9 +/- 7% (n = 5 pairs, P < 0.01), but flow cytometry revealed no differences in SMC viability, apoptosis, or necrosis. While IMA-derived SMC continued to proliferate beyond passage 20 during serial subculture, all AAA-derived SMC developed replicative senescence by passage 12. CONCLUSIONS: AAA-derived SMC exhibit a distinct morphologic appearance in culture, a diminished proliferative capacity compared to SMC from the adjacent IMA, and a limited in vitro life span. These differences reflect an intrinsic alteration in SMC growth capacity independent of age alone. Tissue-specific processes leading to accelerated replicative senescence may therefore contribute to the selective medial SMC depletion observed in AAAs.

Preoperative treatment with doxycycline reduces aortic wall expression and activation of matrix metalloproteinases in patients with abdominal aortic aneurysms.

PURPOSE: Matrix metalloproteinases (MMPs) are considered to play a central role in the pathogenesis of abdominal aortic aneurysms (AAAs). Doxycycline (Dox) has direct MMP-inhibiting properties in vitro, and it effectively suppresses the development of elastase-induced AAAs in rodents. The purpose of this study was to determine if treatment with Dox suppresses MMPs within human aneurysm tissue and to elucidate the molecular mechanisms underlying this effect. METHODS: Aneurysm tissues were obtained from 15 patients with an AAA, eight of whom had been treated with Dox before surgery (100 mg orally twice a day for 7 days). Protein extracts were examined by means of gelatin zymography and immunoblot analysis, and RNA was examined by means of reverse transcription-polymerase chain reaction (RT-PCR). The effects of Dox on MMP production were further examined in human THP-1 mononuclear phagocytes in vitro. RESULTS: No detectable difference was found between groups by using substrate zymography as a means of assessing total MMP activity, but Dox treatment was associated with a slight (24.4%) reduction in the activated fraction of 72-kDa gelatinase (MMP-2; P <.05). In contrast, a 2.5-fold reduction in the amount of extractable 92-kDa gelatinase (MMP-9) protein in Dox-treated patients was revealed by means of immunoblot analysis (P <.05). Also, a 5.5-fold (81.9%) reduction in MMP-9 messenger RNA (mRNA) in Dox-treated patients was demonstrated by means of quantitative competitive RT-PCR (mean +/- SE, mol MMP-9/mol beta-actin: 1.3 +/- 0.5 vs 7.2 +/- 3.1; P <.04). There was no significant difference between groups in the relative expression of MMP-2 protein or mRNA. In cultured THP-1 monocytes stimulated with phorbol ester, the expression of MMP-9 protein and mRNA were both decreased after exposure to relevant concentrations of Dox in vitro. CONCLUSION: In addition to its recognized effects as a direct MMP antagonist, Dox may influence connective tissue degradation within human aneurysm tissue by reducing monocyte/macrophage expression of MMP-9 mRNA and by suppressing the post-translational processing (activation) of proMMP-2. Through this complementary combination of mechanisms, treatment with Dox may be a particularly effective strategy for achieving MMP inhibition in patients with an AAA.

Tc-99m sulfur colloid scintigraphy for detecting perigraft flow following endovascular aortic aneurysm repair: A feasibility study.

PURPOSE: To determine if scintigraphy with Tc-99m sulfur colloid can be used to detect perigraft flow after stent-graft repair of abdominal aortic aneurysm (AAA). METHODS: Twenty-three men and two women aged 56-84 years (mean 71 years) underwent endoluminal AAA repair as part of the EVT Phase II trial [EVT = Endovascular Technologies (Menlo Park, CA, USA)]. Aneurysm size averaged 5.4 cm (range 3-8 cm). Sixteen bifurcated, seven tube, and two aorto-uniiliac grafts were placed. Two days after stent-graft placement, patients underwent both contrast-enhanced computed tomography (CT), including delayed views, and Tc-99m sulfur colloid scintigraphy. RESULTS: Perigraft flow was found in only one patient at completion of angiography. Four additional patients had perigraft flow, discovered during their postoperative follow-up CT. Four patients had leaks at an attachment site and one had retrograde branch flow. Tc-99m sulfur colloid scintigraphy failed to diagnose any of the five leaks prospectively. In two of these patients, however, some abnormal paraaortic activity was noted in retrospect. CONCLUSION: Tc-99m sulfur colloid scintigraphy was unable to demonstrate endoleak with either rapid flow (attachment site leak) or slow filling (branch flow).

Differential expression of prostaglandin E2 and interleukin-6 in occlusive and aneurysmal aortic disease.

BACKGROUND: Both aortoiliac occlusive disease (AIOD) and abdominal aortic aneurysm disease (AAA) are traditionally considered degenerative conditions that are caused by atherosclerosis. Although it is becoming apparent that the pathophysiology of each condition has its own determinants, inflammation is thought to play a role in each. The purpose of this study was to analyze the inflammatory cytokines interleukin-6 (IL-6) and prostaglandin E2 (PGE2) in aortic disease and compare AAA with AIOD, as well as to compare both with normal aorta. METHODS: Aortic tissue was harvested at the time of aortic reconstructive surgery for AAA (n = 13) and AIOD (n = 14) or at time of organ harvest for normal (n = 16) aortic specimens. Whole organ cultures were immediately established, and the culture medium was collected after 72 hours. An enzyme-linked immunosorbent assay was used to assay for PGE2 and a lymphoproliferative assay was used to quantitate IL-6. Statistical analysis was performed using paired 2-tail t tests. RESULTS: Normal aorta expressed much less PGE2 (384 +/- 67 ng/mL) than either AAA (11,093 +/- 7,411 ng/mL) (P < .001) or AIOD (13, 719 +/- 3,355 ng/mL) (P < .002). However there was no statistically significant difference in PGE2 expression between the AAA and AIOD groups (P = . 44). The IL-6 assay also showed that normal aorta had very little expression (1,861 +/- 334 U/mL) compared with either AAA (14,329 +/- 4,159 U/mL) (P = . 02) or AIOD (39,805 +/- 8,426) (P < .001). Comparison between AAA and AIOD revealed significantly higher expression of IL-6 by the AIOD cultures (P = .03). CONCLUSIONS: AAA and AIOD are associated with increased expression of the proinflammatory cytokines PGE2 and IL-6. However, AIOD is associated with a much higher level of IL-6 expression than is AAA, although the level of PGE2 expression is the same. This differential expression of IL-6 may help explain the pathogenesis of these 2 distinct aortic diseases.

Indomethacin inhibits expansion of experimental aortic aneurysms via inhibition of the cox2 isoform of cyclooxygenase.

PURPOSE: Cyclooxygenase, either the cox1 or cox2 isoform, controls synthesis of prostaglandin E2 (PGE2), which regulates expression of matrix metalloprotease-9 (MMP-9). PGE2 and MMP-9 are elevated in aortic aneurysms. The mechanisms and time course of the inhibition of aneurysm expansion with a nonspecific cyclooxygenase inhibitor, indomethacin, were determined in an animal model. METHODS: Rats underwent aortic perfusion with saline (n = 40) as controls or with elastase. Elastase-treated animals received no treatment (n = 82) or received indomethacin (n = 73). Aortic diameters were determined at the time of aortic perfusion and when the rats were killed. The aortas were harvested and used for whole organ culture, substrate gel zymography, or histologic analysis. RESULTS: The control group demonstrated little change in aortic diameter. All the elastase-only animals developed aneurysms (maximal aortic diameter, 5.27 +/- 2.37 mm on day 14). Indomethacin markedly decreased the rate of aortic expansion (maximum aortic diameter, 3.45 +/- 1.11 mm; P <.001 vs the elastase-only group). The enzyme-linked immunosorbent assay of aortic explant culture media showed that PGE2 synthesis paralleled aortic expansion, and indomethacin decreased PGE2 synthesis. Histologically, the aortic elastin architecture was destroyed in the elastase group, but was preserved with indomethacin treatment. In situ, hybridization for cox1 and cox2 showed that cox2, but not cox1, was expressed and was co-localized by immunohistochemistry to macrophages associated with the aortic wall. Decreased levels of MMP-9 activity with indomethacin were shown by means of substrate zymography. MMP-9 was also localized to macrophages. CONCLUSION: Indomethacin attenuates aneurysm growth, and its effects are mediated via inhibition of the cox2 isoform of cyclooxygenase, which decreases PGE2 and MMP-9 synthesis.

Source of elastin-degrading enzymes in mycotic aortic aneurysms: bacteria or host inflammatory response?

Elastolytic matrix metalloproteinases play a central role in the development of chronic atherosclerotic aortic aneurysms, but mycotic aortic aneurysms are a distinct and unusual form of aneurysm disease caused by bacterial infection. Mycotic aortic aneurysms follow a more rapid and unpredictable course than chronic aneurysm disease and they exhibit a predilection for the suprarenal aorta, further implying unique pathophysiologic mechanisms. The purpose of this study was to examine the nature and source of elastin-degrading enzymes in mycotic aortic aneurysm. Bacterial isolates and aortic tissues were obtained from four consecutive patients undergoing surgical repair of suprarenal mycotic aortic aneurysm. Using an in vitro 3H-labeled elastin degradation assay, elastin-degrading enzyme activity was only observed in the bacteria-conditioned medium from an isolate of Pseudomonas aeruginosa. Elastin-degrading enzyme activity in the aortic tissue homogenate of this patient was abolished by the serine protease inhibitor, phenylmethylsulfonyl fluoride, but it was not suppressed by the metalloproteinase inhibitor, ethylenediamine tetraacetic acid (EDTA). In contrast, elastin-degrading enzyme activity in the bacterial-conditioned medium was decreased by about half by both phenylmethylsulfonyl fluoride and EDTA. Elastin substrate zymography revealed two phenylmethylsulfonyl fluoride-inhibitable elastin-degrading enzyme activities in the aortic tissue homogenate that corresponded to human neutrophil elastase (approximately 30 kDa) and its stable complex with alpha 1-proteinase inhibitor (approximately 80 kDa), but no activity attributable to Pseudomonas elastase, a 33-kDa metal-dependent enzyme. Human neutrophil elastase was readily detected throughout mycotic aortic aneurysm tissues by immunohistochemistry, but elastolytic metalloproteinases were only occasionally observed. The results of this study suggest that the elastin-degrading enzyme produced in mycotic aortic aneurysm are largely serine proteases of host neutrophil origin, rather than elastases produced by the infecting microorganisms or the macrophage-derived metalloproteinases typically observed in atherosclerotic aneurysm disease. Further studies will be needed to extend these findings to a larger number of patients with mycotic aortic aneurysm and those caused by additional microorganisms.

Surgical treatment of patients with symptomatic vertebrobasilar insufficiency.

We report our experience with surgical management of symptomatic vertebrobasilar insufficiency (VBI). Forty revascularizations were carried out in 39 patients over 90 months. Dizziness (52%) and syncope/presyncope (32%) were the most common symptoms. Arteriography was performed in all patients, with subclavian steal seen in 55% of patients. Procedures performed included 22 cases of carotid-subclavian bypass or transposition (55%), seven direct vertebral reconstructions (17.5%), four great vessel reconstructions (10%), four isolated carotid endarterectomies (10%), and three axilloaxillary bypasses (7.5%). One patient died, and the combined morbidity and mortality rate was 15%. Outpatient follow-up was available on 37 of the 38 patients discharged alive. At a mean follow-up of 16.4 months, 34 patients had no VBI complaints. Three of four patients treated with CEA alone had persistent VBI complaints. We conclude that a variety of anatomic lesions can result in VBI symptoms, with subclavian steal being the most common. Procedures which directly correct the anatomic abnormality result in sustained symptom resolution with acceptable complication rates.

Endovascular stent grafts for aneurysmal and occlusive vascular disease.

BACKGROUND: This report details our initial experience with two types of endovascular grafts- one for the treatment of infrarenal abdominal aortic aneurysms and the other for the treatment of iliac artery occlusive disease. METHODS: An abdominal aortic aneurysm was repaired in 34 patients using 3 different types of Ancure endografts (Menlo Park, California). Control patients (n = 9) had a standard aneurysm repair. Patients with chronic lower extremity ischemia (n = 7) secondary to iliac artery occlusive disease were treated with a Hemobahn endograft (W. L. Gore & Associates, Flagstaff, Arizona). RESULTS: Ancure graft deployment was achieved in 33 of 34 (97.1%) patients. Perioperative mortality for the Ancure and control group patients was 2.9% and 0%, respectively. Periprosthetic leaks were identified within 48 hours of deployment in 6 (18.2%) Ancure graft patients. All but 2 of the leaks resolved on serial follow-up. Additional endovascular procedures were required in 11 (32.4%) Ancure graft patients at the initial procedure or during follow-up to correct graft or arterial stenoses. Patients treated with an endovascular graft had significantly less blood loss and shorter hospital stays than control group patients. For Hemobahn patients, the technical success for graft deployment was 100%. There were no perioperative deaths. The ankle/brachial index increased from a mean of 0.52 preoperatively to 0.86 postoperatively (P = 0.004). One patient required a Wallstent in follow-up to correct a graft wrinkle. Angiography at 6 months demonstrated mild intimal hyperplasia in the stent graft in 5 of 6 patients. CONCLUSIONS: These early results support the potential for endovascular grafts in the treatment of aneurysmal and occlusive vascular disease. Further modifications in the devices and deployment techniques are necessary to reduce the incidence of periprosthetic leaks, graft limb stenoses, and intimal hyperplasia.

Spontaneous closure of selected iatrogenic pseudoaneurysms and arteriovenous fistulae.

PURPOSE: We report our approach to the management of postcatheterization femoral artery pseudoaneurysms and arteriovenous fistulae in an attempt to determine the frequency of spontaneous resolution of selected lesions. METHODS: We studied 196 pseudoaneurysms, 81 arteriovenous fistulae, and 9 combined lesions that were identified by duplex scan. Indications for immediate surgical repair included pseudoaneurysm greater than 3 cm, enlarging hematoma, pain, groin infection, nerve compression, limb ischemia, concomitant surgical procedure, and patient refusal or inability to comply with follow-up. All other lesions were observed. RESULTS: One hundred thirty-nine patients underwent prompt surgical repair, and 147 patients were initially managed without operation. There were no limb-threatening complications associated with nonoperative management in this subset of patients. Eighty-six percent of the lesions being observed resolved spontaneously within a mean of 23 days, whereas 14% required surgical closure for a variety of reasons (at a mean of 111 days after the initial diagnosis). There was no statistically significant difference in the rate of spontaneous pseudoaneurysm closure (89%) as opposed to fistulae (81%) (p < 0.17). By life-table analysis, 90% of selected pseudoaneurysms had resolved by 2 months. Patients selected for observation underwent an average of 2.6 duplex scans per patient versus 1.4 scans per patient for those treated with immediate surgery (p < 0.01). CONCLUSION: The natural history of stable pseudoaneurysms and arteriovenous fistulae is benign and frequently results in spontaneous resolution, which allows properly selected patients to be managed without operation.