Endovascular repair of popliteal artery aneurysms with Anaconda limbs: technique and early results.

OBJECTIVES: The objective is to report the feasibility and technique of treating popliteal artery aneurysms (PAA) with a stent made of nitinol rings externally supported by thin polyester (Anaconda limbs). BACKGROUND: PAA are the most common peripheral aneurysms. The main limitations of stents used in these settings are: short lengths, longitudinal and horizontal compliance mismatch; graft failure from angulation and movement at the joint level; and dislodgment. METHODS: This is a prospective multicenter cohort study of consecutive symptomatic and asymptomatic PAA treated in tertiary vascular centers. Outcomes included patency of the stent and postoperative time-to-independent-ambulation and to-climb-a-flight-of-stairs. RESULTS: Fourteen PAA were treated in 12 men, age 72 +/- 3 years. The median ASA classification was 2.5. The length of artery covered was 147 +/- 41 mm. The PAA diameter was 31 +/- 5 mm, 6 were symptomatic. One stent was used in 6 aneurysms, two in 7, and three in 1. The average stent diameter was 10 +/- 1 mm. The length of the proximal neck was 24 +/- 6 mm with a diameter of 9.8 +/- 1.9, and length of the distal neck 23 +/- 3 mm with a diameter of 8.7 +/- 1.2 mm. In 6 aneurysms, the stent crossed the knee joint. There was no mortality, and one stent occluded (primary patency 93% at 6 +/- 3 months). The median hospital stay was 1.7 days, time to independent ambulation was 3 hr and the time to climbing a flight of stairs was 1 day. CONCLUSIONS: The use of Anaconda limbs for endovascular repair of PAA is feasible and safe.

Intravascular lipoma of the left common femoral vein.

Lipomatous tumors of the heart and major central veins are unusual pathologic findings. We report an intravascular lipoma arising directly from the wall of the left common femoral vein (LCFV) in a patient who had progressive left leg swelling and in whom a deep venous thrombosis in the LCFV was initially diagnosed. this is the first case report if such a tumor in the literature. the computed tomography, magnetic resonance imaging, and intraoperative features are presented. the procedure of tumor excision and venous reconstruction with a cadaveric allograft is described.

Decision analysis for the surgeon.

Surgical practice, by nature, is full of important decision making scenarios. Surgeons have begun to utilize the decision sciences as a methodology of approaching clinically relevant surgical problems. This article provides a brief overview of some of the important concepts of the decision sciences as they apply to practicing surgeons. Concepts discussed include the basic principles behind decision trees, valuing outcomes, and Markov modeling as well as the pros and cons of the decision analytic approach. Decision analysis is a valuable aid in determining answers to clinical scenarios, and understanding the principles behind this methodology is an important addition to the armamentarium of all practicing surgeons.

Safety of outpatient arterial stenting.

OBJECTIVE: To assess the safety of performing iliac arterial stenting as an outpatient procedure. METHODS: Retrospective analysis of safety including all patients referred for elective iliac arterial stenting over a 1-year period. Sources of data for the analysis included pre- and post-stenting vascular surgical consultation records, hospital case notes, diagnostic and interventional angiography reports, computerized laboratory data, nursing records from our angiography holding area, and the results of routine post-stenting telephone follow-up. RESULTS: There were 29 outpatient iliac stenting procedures in 28 patients (19 men and 9 women, age range 41.0 to 79.8 years, mean age 66.1 years). Of these 29 procedures, 17 involved unilateral iliac stenting, and 12 involved bilateral iliac stenting. Adjunctive renal artery angioplasty was performed in 1 patient and internal iliac angioplasty and stenting were performed in 2 patients. A total of 51 stents were deployed through 42 femoral punctures via introducer sheaths ranging in size from 6 to 8 French. Percutaneous hemostatic closing devices were used in 6 punctures. Two patients required overnight inpatient observation for moderate-size hematomas; these had no clinical sequelae. All others were discharged safely 5 to 6 hours after sheath removal. No clinically significant sequelae were identified in any patient. CONCLUSION: Arterial stenting can be performed safely on an outpatient basis.

Determinants of outcome after carotid endarterectomy.

BACKGROUND: The efficacy of carotid endarterectomy for selected patients has been evaluated with randomized controlled clinical trials. The generalizability of these studies to average surgical practice remains an important public health concern. OBJECTIVE: The objective of the study was to determine the predictors of outcome after carotid endarterectomy on a regional basis. PATIENTS AND METHODS: The study was designed as a retrospective cohort study and included all consecutive patients presented for carotid endarterectomy at the 8 University of Toronto-affiliated hospitals in the period from January 1, 1994, to December 31, 1996. The main outcome measure was 30-day postoperative stroke or death rate. RESULTS: During the study interval, 1280 primary carotid endarterectomies were performed. The overall combined stroke and death rate was 6.3% for all patients who underwent endarterectomy (4.0% for patients who were asymptomatic). The significant predictors of poor outcome were the following: presenting symptoms (odds ratio, 1.74; 95% confidence interval [CI], 0.96, 3.12), low surgeon volume (<6 cases per year; odds ratio, 3.98; 95% CI, 1.65, 9.58), and left-sided surgery (odds ratio, 1.72; 95% CI, 1.07, 2.76). CONCLUSION: These data suggest that adoption of the recommendations of the symptomatic carotid endarterectomy trials is appropriate. However, endarterectomy for asymptomatic lesions remains of uncertain benefit on a regional basis and must be individualized to the experience of the specific surgeon. The surgeon volume/outcome relationship that is identified in this study suggests a need for a minimum volume threshold for this procedure.

Long-term outcomes after upper limb arterial injuries.

OBJECTIVE: To assess long-term outcomes in multisystem trauma victims who have arterial injuries to upper limbs. DESIGN: A retrospective case series. SETTING: Tertiary care regional trauma centre in a university hospital. PATIENTS: All consecutive severely injured patients (Injury Severity Score greater than 15) with an upper limb arterial injury treated between January 1986 and January 1995. Demographic data and the nature and management of the arterial and associated injuries were determined from the trauma registry and the hospital records. OUTCOME MEASURES: Death rate, discharge disposition, residual disabilities and functional outcomes as measured by the Glasgow Outcome Scale. RESULTS: Twenty-five (0.6%) of 4538 trauma patients assessed during the study period suffered upper extremity arterial injuries. Nineteen of them were victims of blunt trauma. The death rate was 24%. There were 10 primary and no secondary amputations. An autogenous vein interposition graft was placed in 10 patients. Concomitant fractures or nerve injuries in the upper limb were present in 80% and 86% of the patients, respectively. Long-term follow-up data (mean 2 years) were obtained in 16 of the 19 who survived to hospital discharge. The residual disability rate was high. It included upper limb joint contractures, pain and persistent neural deficits (69%). Associated injuries in other body areas also contributed to overall disability. Only 21% of the patients recovered completely or had only minor disabilities. CONCLUSIONS: Associated injuries, rather than the vascular injury, cause long-term disability in the multisystem trauma victim who has upper extremity involvement. Persistent neural deficits, joint contractures and pain are the principal reasons for long-term impairment of function.

Flow-independent angiography for peripheral vascular disease: initial in-vivo results.

Flow-independent angiography (FIA), an approach that isolates arterial blood using MR relaxation characteristics rather than flow effects, was evaluated for application in peripheral vascular disease (PVD). First, pilot studies were conducted in which FIA coronal projection images were obtained from controls and symptomatic patients with PVD to assess clinical utility. All control images corresponded to the expected leg arterial anatomy with little interference from deep veins (one of five) and muscle (zero of five). Superficial venous signal was less well suppressed in comparison to deep veins (four of five). Images of symptomatic patients were less consistent with difficulty suppressing muscle and deep venous signal in some cases and edema when present. We then compared T2 values for muscle (T2m, tibialis anterior), arterial blood (femoral and popliteal arteries), and venous blood (femoral, popliteal, and saphenous veins) in controls (n = 8) and symptomatic patients with intermittent claudication (n = 5) or ischemic rest pain (n = 7). Changes in T2 measurements of various tissues accounted for poorer contrast in symptomatic patients. Patients with ischemic rest pain had significantly higher T2m compared with controls (T2m = 39.3 +/- 2.1 (1 standard error of the mean [SEM]) versus 30.9 +/- .4, P < .01). For all measurements, other than saphenous vein, variances were greater in symptomatic patients. To realize the inherent advantages of FIA for this clinical application, additional work on suppression of signals from muscle, veins, and edema is required. One promising approach involves shifting from projection images to three-dimensional acquisitions for improved tissue suppression.

Sudden rupture of an indirect inguinal hernial sac with extravasation in two patients on continuous ambulatory peritoneal dialysis.

Continuous ambulatory peritoneal dialysis (CAPD) is commonly used to treat patients suffering from end-stage renal failure. This method can be used on a long-term basis and in the short term for patients awaiting renal transplantation. Inguinal hernias are a potential source of morbidity for these patients. Therefore, when patients with inguinal hernias require long-term peritoneal dialysis, the hernia should be repaired if the patient's medical status will allow it. The authors report on two patients maintained on CAPD who experienced rapid enlargement and perforation of a previously undiagnosed asymptomatic inguinal hernia. The hernia was repaired successfully, without complication, in both cases.

Modulation of macrophage procoagulant activity by arachidonic acid metabolites.

Macrophage (M phi)-mediated fibrin deposition via induction of procoagulant activity (PCA) is an important component of the host response during various infections. While endotoxin (LPS) is a well-known stimulus of PCA, the factors modulating its activity within the inflammatory microenvironment are unknown. The purpose of these studies was to determine the relative roles of two pathways of arachidonic acid metabolism, i.e., the cyclooxygenase (CO) and 5-lipoxygenase (5-LO) pathways, in modulating M phi PCA induction by LPS. Thioglycolate-elicited murine peritoneal M phi were treated with the CO inhibitor indomethacin (INDO), the 5-LO inhibitor nordihydroguaiaretic acid (NDGA), or control vehicle for 15 min prior to a 4-hr exposure to LPS (10 micrograms/ml). The ability of M phi to shorten the clotting time of plasma (i.e., PCA) was measured and clotting times were converted to PCA units via a thromboplastin standard. While CO blockade had no effect on PCA induction by LPS (without INDO 30 microM 446 +/- 131, with INDO 30 microM 546 +/- 193, mU/2 x 10(6) cells, n = 4), NDGA caused a dose-dependent inhibition (IC50 = 3 microM) without affecting cell viability (without NDGA 3 microM 446 +/- 131, with NDGA 3 microM 191 +/- 67, mU/2 x 10(6) cells, n = 6, P less than 0.05). Induction of PCA by Escherichia coli was similarly inhibited (E. coli 10(6) alone = 518 +/- 130; with NDGA 3 microM = 234 +/- 100, n = 2). Combined NDGA/INDO reduced PCA comparable to NDGA alone, ruling out the possibility that NDGA acted through generation of inhibitory prostanoids like PGE2.(ABSTRACT TRUNCATED AT 250 WORDS)

Platelet-activating factor modulates endotoxin-induced macrophage procoagulant activity by a protein kinase C-dependent mechanism.

Macrophage procoagulant activity is an important mediator of extravascular fibrin deposition at sites of infection and appears to contribute to the pathogenesis of several infectious disease processes. Previous studies have shown that the inflammatory mediator platelet-activating factor was able to prime macrophages for induction of procoagulant activity by bacterial lipopolysaccharide. The present studies were designed to examine the mechanism of this priming effect. Platelet-activating factor (100 nM) primed macrophages for procoagulant activity generation in response to endotoxin at concentrations as low as 100 ng/ml and also following exposure to Escherichia coli, Bacteroides fragilis, and Staphylococcus aureus. The priming effect occurred following a pretreatment with platelet-activating factor for as short as 1 min, suggesting a rapid activation event. Two different doses of the calcium ionophore ionomycin were used to mimic the peak and sustained effects of platelet-activating factor on cytoplasmic calcium levels (1 microM and 100 nM, respectively). Neither dose was able to mimic the priming effect. However, extracellular calcium was necessary for induction of procoagulant activity and the priming effect. By contrast, the protein kinase C agonist phorbol myristate acetate reproduced the priming phenomenon observed for platelet-activating factor. In further support of the concept that protein kinase C activation mediated the effect of platelet-activating factor, the specific protein kinase C inhibitor staurosporine reversed the ability of platelet-activating factor to augment induction of macrophage procoagulant activity by endotoxin. These data suggest mechanisms by which inflammatory mediators within the microenvironment of infection might modulate the host response to bacterial pathogens.

Platelet-activating factor primes endotoxin-stimulated macrophage procoagulant activity.

Macrophage procoagulant activity (PCA) at the site of inflammation may be induced by several stimuli including bacteria and endotoxin (LPS). The local factors controlling PCA induction are poorly defined. The lipid mediator platelet-activating factor (PAF) is ubiquitous to inflammatory sites. To determine the effect of PAF on LPS-induced PCA, thioglycolate-elicited murine peritoneal macrophages were exposed to PAF (10(-7) M) or control medium for 30 min and then stimulated with LPS (10 micrograms/ml) for 2, 4, or 6 hr. The ability of macrophages to shorten the clotting time of plasma (ie., PCA) was then measured and clotting times were converted to PCA units using a thromboplastin standard. Cytosolic calcium ([Ca2+]i) measurements were made using the calcium-sensitive fluorescent dye indo-1. PAF alone did not induce a rise in PCA expression (medium alone, 47 +/- 11 mU/10(6) cells; PAF alone, 49 +/- 12 mU/10(6) cells at t = 4 hr), but PAF treatment prior to LPS exposure resulted in a significant increase in the LPS-stimulated expression of PCA (LPS alone, 190 +/- 29 mU/10(6) cells; PAF/LPS, 329 +/- 57 mU/10(6) cells at t = 4 hr, P less than 0.05). This priming effect was reversed by the PAF antagonist WEB 2086 (WEB/PAF/LPS, 196 +/- 31 mU/2 x 10(6) cells). Stimulation of cells with PAF alone resulted in a rapid rise in [Ca2+]i (resting, 213 +/- 19 nmole; peak, 577 +/- 35 nmole). This effect was also inhibited by WEB 2086. These data suggest that PAF plays an important role in the modulation of PCA production by macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)