[Development and/or increase of rheumatoid nodules in RA patients following leflunomide therapy]. / Neuauftreten und/oder Zunahme von Rheumaknoten unter Leflunomidtherapie bei RA-Patienten.

This is the first description of the development of rheumatoid nodules in 3 rheumatoid arthritis patients following leflunomide therapy. The nodules were localized at typical sites with preference of the extensor side of hands and elbow. One nodule examined histologically revealed the typical architecture of RA nodules. In all 3 patients the time of onset of nodulosis was about 6 months after initiating the leflunomide therapy. In all 3 patients leflunomide was clinically efficacious concerning RA: remission or near remission was achieved. Due to the extent of nodulosis, the leflunomide therapy had to be stopped in 2 patients. Progression and acceleration of nodulosis is well known following MTX therapy in RA patients. It is caused by adenosine A1 receptor promotion of multinucleated giant cell formation by human monocytes. Leflunomide has no known influence on adenosine metabolism, so different pathogenetic mechanisms must be assumed for the induction of nodulosis by leflunomide.

Exclusion of accessory renal arteries during endovascular repair of abdominal aortic aneurysms.

OBJECTIVE: Adequate proximal neck length is important for proper endovascular treatment of abdominal aortic aneurysms (AAAs). Placement of endografts in AAAs with relatively short proximal necks may require covering the origin of accessory renal arteries. Exclusion of these arteries carries the theoretical concern of regional renal ischemia associated with loss of parenchyma or worsening hypertension. We reviewed our experience with accessory renal exclusions during endovascular AAA repair to determine the frequency and severity of complications. METHODS: Complete records were available for review on 311 of 325 consecutive patients treated with endovascular grafts for AAAs from February 6, 1996, to March 15, 2001. The presence of accessory renal arteries was ascertained from preoperative/intraoperative aortography or from computed tomographic scanning. Sizes of the accessories were measured by using the main renal arteries as a reference. Considerations for excluding the accessory renal arteries were based on the likelihood of successful proximal attachment to healthy aorta, an accessory vessel whose size does not exceed the diameter of the main renal artery, and the absence of renal disease. RESULTS: The mean follow-up was 11.5 months. Fifty-two accessory renal arteries were documented in 37 patients (12%), ranging from 1 to > or =3 per patient. Of these, 26 accessory renal arteries were covered in 24 patients. Patients ranged in age from 57 to 85 years (mean, 74.1 years), with 20 men and 4 women. The Ancure device was used in 23 patients and the Excluder device in one. Of the accessories excluded, 22 originated above the aneurysm and 4 originated directly from the aneurysm itself. There were no perioperative mortalities. One patient died 5 months after surgery from an unrelated condition. There was one type I (distal) endoleak and no type II endoleaks. Five patients (21%) had segmental renal infarction associated with the side of accessory renal artery exclusion. Only one patient with segmental infarction had significant postoperative hypertension that resulted in changes in blood pressure medication. The blood pressure reverted to normal 3 months later. One patient with a stenotic left main renal artery required exclusion of the accessory renal artery for successful proximal attachment. Serum creatinine levels remained unchanged throughout follow-up in all but one patient, in whom progressive postoperative renal failure developed despite normal renal flow scan, presumably from intraoperative manipulation and contrast nephropathy. CONCLUSION: Exclusion of accessory renal arteries to facilitate endovascular AAA repair appears to be well tolerated. Long-term sequelae seem infrequent and mild.

Adenovirus-mediated gene transfer of human inducible nitric oxide synthase in porcine vein grafts inhibits intimal hyperplasia.

OBJECTIVE: The aim of this study is to determine whether adenoviral inducible nitric oxide synthase (iNOS) gene transfer could inhibit intimal hyperplasia (IH) in porcine internal jugular veins interposed into the carotid artery circulation. METHODS: Porcine internal jugular veins were transduced passively with 1 x 10(11) particles of an adenoviral vector carrying either the human iNOS (AdiNOS) or beta-galactosidase (AdlacZ) cDNA for 30 minutes and then interposed into the carotid artery circulation. Segments of each vein graft were maintained in an ex vivo organ culture to measure nitrite accumulation, a marker of nitric oxide synthesis. The grafts were analyzed immunohistochemically for the presence of neutrophils, macrophages, and leukocytes by staining for myeloperoxidase, ED1, and CD45, respectively, at 3 (n = 4) and 7 (n = 4) days. Morphometric analyses and cellular proliferation (Ki67 staining) were assessed at 3 (n = 4), 7 (n = 4), and 21 days (n = 8). RESULTS: AdlacZ-treated vein grafts demonstrated high levels of beta-galactosidase expression at 3 days with a gradual decline thereafter. Nitrite production from AdiNOS-treated vein grafts was approximately fivefold greater than AdlacZ-treated grafts (P =.00001). AdiNOS or AdlacZ treatment was associated with minimal graft inflammation. Cellular proliferation rates were significantly reduced in AdiNOS-treated grafts as compared with controls at both 3 (41%, P =.000004) and 7 days (32%, P =.0001) after bypass. This early antiproliferative effect was most pronounced at the distal anastomosis (65%, P =.0005). The iNOS gene transfer reduced the intimal/medial area ratio in vein grafts at 7 (36%, P =.009) and 21 days (30%, P =.007) versus controls. This inhibition of IH was again more prominent in the distal segments of the grafts (P =.01). CONCLUSION: Adenovirus-mediated iNOS gene transfer to porcine internal jugular vein grafts effectively reduced cellular proliferation and IH. Although iNOS gene transfer reduced IH throughout the entire vein graft, the most pronounced effect was measured at the distal anastomosis. These results suggest potential for iNOS-based genetic modification of vein grafts to prolong graft patency.

Doppler US gating of cardiac MR imaging.

RATIONALE AND OBJECTIVES: Electrocardiographic (ECG) gating of cardiac magnetic resonance (MR) imaging has been problematic for many reasons. The purpose of this study was to demonstrate the feasibility of using Doppler ultrasound (US) gating, either directly off the moving cardiac wall or the systolic upstroke of the arterial signal from the great vessels in neck, in alternative gating modes. MATERIALS AND METHODS: A 2.5-MHz, range-gated Doppler US device was used with A-mode guidance for gating directly off left ventricular wall motion. A 4- or 8.1-MHz, continuous-wave (CW) Doppler US device was used for gating off the systolic upstroke from the great vessels in the neck. The subject undergoing imaging held the transducer against his chest for range-gated Doppler US and against his neck for 8.1-MHz CW Doppler US. The 4-MHz transducer was strapped to the subject's neck. Modified Doppler signals were fed back into the gating circuitry of the MR imager to achieve cardiac synchrony. RESULTS: Cardiac gating was achieved by using both the range-gated technique directly off the cardiac wall and the CW method off blood flow from the great vessels. Problems occurred with radiofrequency shielding during the range-gated method; however, these problems were almost completely removed by use of the CW Doppler probes. CONCLUSION: Doppler US gating of MR images is possible and potentially could overcome many shortcomings of ECG gating. Subsequent embodiments of the technique will require improved radiofrequency shielding in the range-gated technique.

Is routine use of the intensive care unit after elective infrarenal abdominal aortic aneurysm repair necessary?

INTRODUCTION: Postoperative care after infrarenal abdominal aortic aneurysm (AAA) repair has traditionally involved admission to the intensive care unit (ICU). With the advent of endovascular AAA repair, the management of open procedures has received increased scrutiny. We recently modified our AAA clinical pathway to include selective use of the ICU. METHODS: Consecutive elective infrarenal AAA repairs performed by members of the vascular surgery division at a university medical center from 1994 to 1999 were analyzed retrospectively with a computerized database, the Medical Archival Retrieval System. Group I consisted of 245 patients who were treated in the ICU for 1 or more days, and Group II included 69 patients admitted directly to the floor. Ruptured, symptomatic, suprarenal, endovascular, and reoperative repairs were excluded. Outcome variables were compared over the 6-year period. RESULTS: Floor admissions increased over the study period with 0%, 0%, 3.3%, 16.3%, 48.6%, and 43.6% of patients admitted directly to the surgery ward from 1994 to 1999. The average ICU length of stay declined from 4.6 to 1.2 days, whereas the hospital length of stay decreased from 12.5 to 6.8 days from 1994 to 1999. The change in ICU use had no effect on death (2.4% in Group I vs 0% in Group II). Major and minor morbidity was comparable. Hospital charges were significantly lower for patients in Group II. CONCLUSION: A policy of selective utilization of the ICU after elective infrarenal AAA repair is safe. It can reduce resource use without a negative impact on the quality of care.

Long-term fate of the aneurysmal sac after endoluminal exclusion of abdominal aortic aneurysms.

PURPOSE: Shrinkage of an abdominal aortic aneurysm (AAA) is the hallmark of successful endoluminal treatment. Our goal was to prospectively assess the midterm to long-term shrinkage of the AAA sac after endovascular repair. METHODS: A total of 123 patients with AAA underwent endoluminal treatment with the Ancure device at our institution between February 1996 and February 2000. At least a 1-year follow-up was available for 70 of the 123 patients. AAA sac size, presence of endoleaks, calcifications, and outcome data were collected on these patients at 6, 12, 24, and 36 months after repair and compared with the preoperative AAA size and characteristics. All endoleaks found at the 6-month follow-up visit were treated aggressively with embolotherapy. An AAA sac regression of 0.5 cm or more was considered the minimum measurable decrease. Regression of the sac diameter to 3.5 cm or less was considered a complete collapse of the sac. RESULTS: Successful endoluminal repair was accomplished in 119 of 123 patients. The mortality rate was 0.8% (1/123). There was a steady decrease in AAA sac size from baseline (5.56 +/- 0.1 cm), to 6 months (5.0 +/- 0.14 cm, P =.0006), to 12 months (4.65 +/- 0.13 cm, P =.04), and to 24 months (4.26 +/- 0.16 cm, P =.03). At 24 months, 74% (29/39) had a decrease in sac size of 0.5 cm or more, with 28% (11/39) complete collapse. Patients with initial endoleaks had the same likelihood of regression of sac size (> or = 0.5 cm) when compared with the group of patients with no endoleaks at the 24-month evaluation (64% vs 76%, P =.09). CONCLUSION: Endoluminal AAA repair resulted in a significant reduction in sac size that continues up to 2 years. Significant shrinkage occurs as early as 6 months after placement. The initial presence of endoleaks does not predict the lack of sac regression.

[Ultrasound determination of sacral position in the frontal plane]. / Die sonographische Bestimmung der Kreuzbeinstellung in der Frontalebene.

AIM OF THE STUDY: The position of the sacrum in the frontal plane is important for the statics of the spine. The most common method of investigating the sacrum is its visualisation on an antero-posterior X-ray film. The aim of this study was to find a method of determining the position of the sacrum in the frontal plane by sonography. METHOD: Criteria for the correct image of the upper rim of the sacrum are presented and the procedure for measuring sacral tilt is introduced. The results of the sonographic measurements of 107 patients are compared with the results of X-ray measurements. The intraindividual differences are described and statistically evaluated. RESULTS: Almost 90% of the patients revealed a difference between the sonography and the radiology measurement of less than three millimeters. The overall sensibility was 80%. The specificity was 82%. The results were calculated for different age groups. They turned out to be better in children and adolescents than in adult patients. Obese adults had significantly worse results than patients with normal body weight. CONCLUSIONS: This study suggests that the method presented can help to provide reliable information on the position of the sacrum, especially in children and adolescents. By using sonography we can partly reduce the necessary X-ray exposure, especially in the diagnosis and treatment of leg length discrepancies.

Thrombin injection versus compression of femoral artery pseudoaneurysms.

OBJECTIVE: The compression of femoral artery pseudoaneurysms is a time consuming, painful, and sometimes unsuccessful procedure. Thrombin injection has been advocated as a superior alternative. In this study, we compare our experiences with both techniques. METHODS: All the records of femoral artery false aneurysms that were treated in the vascular laboratory from January 1996 to April 1999 were retrospectively reviewed. Treatment with ultrasound scan-guided compression was compared with treatment with dilute thrombin injection (100 U/mL). RESULTS: Both groups had similar demographics and aneurysm sizes (P >.2). Of the pseudoaneursyms, 88% were caused by cardiac catheterization and the others were the results of femoral artery access for cardiac surgery (6%), arteriography (5%), and renal dialysis (1%). Compression was successful in 25 of 40 patients (63%). Nine persistent aneurysms necessitated operation, and six were treated successfully with thrombin injection. Primary thrombin injection successfully obliterated 21 pseudoaneurysms in 23 patients. Overall, 27 of 29 pseudoaneurysms were treated successfully with thrombin injection (93%). Thrombosis occurred within seconds of the thrombin injection and required, on average, 300 units of thrombin (100 to 600 units). The patients who underwent successful compression required an average of 37 minutes of compression (range, 5 to 70 minutes) and required analgesia on several occasions. No patients in the thrombin group required analgesia or sedation. Neither group had complications. A cost analysis shows that thrombin treatment results in considerable savings in vascular laboratory resource use but not in overall hospital expenditures. CONCLUSION: Ultrasound scan-guided thrombin injection is a safe, fast, and painless procedure that completely obliterates femoral artery pseudoaneurysms. The shift from compressive therapy to thrombin injection reduces vascular laboratory use and is less expensive, although it does not significantly impact hospital costs.

Speckle decorrelation flow measurement with B-mode US of contrast agent flow in a phantom and in rabbit kidney.

PURPOSE: To use speckle decorrelation in the presence of ultrasonographic (US) contrast agent as an alternative flow measurement technique to Doppler US. MATERIALS AND METHODS: In vivo and in vitro studies were performed. A tube with flowing saline solution containing contrast agent was positioned horizontally across a US image. The amount of decorrelation between a series of images was recorded. The flow profile across the tube was generated by averaging the decorrelation values and was compared with a Doppler frequency shift image. In addition, B-mode images of six rabbit kidneys were obtained during and after intravenous injection of contrast agent. Images were analyzed to compute the correlation between successive points in time. RESULTS: The velocity profiles across the tube were parabolic, with the fastest flow rates measured in the center of the tube. In the rabbit kidneys, measurements indicated the largest decorrelation rates occurred in the larger vessels. The cortical decorrelation rates were significantly slower than those for the hilar vessels (P < .05) and were relatively angle independent. CONCLUSIONS: Decorrelation flow measurements can be used to estimate flow in vitro and in vivo similar to measurements obtained with Doppler US but with less angle dependence. These measurements could lead to a US perfusion technique.

Management of splenic artery aneurysms: the significance of portal and essential hypertension.

BACKGROUND: Splenic artery aneurysm(s) (SAA) are rare. But the incidence and significance of SAA among patients with portal hypertension (PHTN), especially among those who undergo orthotopic liver transplantation (OLT), have not been clearly delineated. STUDY DESIGN: An 11-year (February 1987 to June 1998) retrospective review of our experience with treated SAA was performed. Patient characteristics, risk factors, clinical presentation, surgical management, aneurysm characteristics, and patient outcomes were assessed. Patients were separated according to a history of PHTN for analysis. Patients were also subdivided into ruptured versus elective presentations. RESULTS: Thirty-four patients (22 in the PHTN group) were treated for SAA during the study period. Sixty-two percent (21 of 34) were women; the average age was 50.6 years. In patients without a history of PHTN (n = 12), essential hypertension was a significant risk factor (p < 0.001) for development of SAA. All patients underwent surgical treatment for SAA: resection with splenectomy (n = 23), ligation with splenectomy (n = 5), ligation of SAA only (n = 4), and vascular reconstruction (n = 2). The average size of all treated SAA was 4.8 +/- 2.6 cm, ranging from 1.5 to 12cm. Operative mortality after SAA rupture (n = 15) was 40%, compared with zero mortality for elective SAA repair (n = 19, p < 0.005). Rupture of SAA was associated with a higher mortality in patients with PHTN compared with patients without such history (56% versus 17%, respectively). After a mean followup period of 46 months, survival after rupture was 60% in contrast to 84% after elective repair. The majority of our patients with a history of PHTN (20 of 22) has undergone OLT, representing 0.46% of all OLT recipients (n = 4,374) during the study period. In four patients, SAA were repaired concurrently during transplantation. Of the 7 patients presented with rupture of SAA after OLT, 6 patients presented within 3 to 16 days postoperatively, with a median of 6 days and an overall mortality of 57%. CONCLUSIONS: Essential hypertension and PHTN appear to be significant risk factors for development of SAA. Rupture of SAA is associated with a significant mortality, highest among patients with PHTN. Elective repair remains a safe and effective method of treatment. The significance of SAA is recognized among patients undergoing liver transplantation. A decision should be made to screen and electively treat SAA found in liver transplant patients, especially if the aneurysm is larger than 1.5 cm. Awareness of the increased rupture risk is crucial in management during the immediate posttransplant period.

Oxygen-dependent chronic obstructive pulmonary disease does not prohibit aortic aneurysm repair.

BACKGROUND: Severe oxygen-dependent chronic obstructive pulmonary disease (COPD) is considered by many to be a contraindication to open abdominal aortic aneurysm (AAA) repair. We reviewed our own experience with this patient population. METHODS: From July 1995 to March 1999, 14 consecutive patients limited by home oxygen-dependent COPD underwent elective open infrarenal AAA repair. Their medical records were reviewed. RESULTS: The mean aortic aneurysm size was 6.3 cm. The mean PaO2 = 70 mm Hg, PaCO2 = 45 mm Hg, forced expiratory volume in 1 second (FEV1) = 34% of predicted, and forced vital capacity (FVC) = 67% of predicted. All 14 patients were extubated within 24 hours, mean length of hospital stay was 5.9 days, and there were no perioperative deaths. CONCLUSIONS: Severe home oxygen-dependent COPD is not a contraindication to safe elective open AAA repair.

Progression of asymptomatic carotid stenosis: a natural history study in 1004 patients.

PURPOSE: The purpose of this study was to delineate the natural history of the progression of asymptomatic carotid stenosis. METHODS: In a 10-year period, 1701 carotid arteries in 1004 patients who were asymptomatic were studied with serial duplex scans (mean follow-up period, 28 months; mean number of scans, 2.9/patient). At each visit, stenoses of the internal carotid artery (ICA) and the external carotid artery (ECA) were categorized as none (0 to 14%), mild (15% to 49%), moderate (50% to 79%), severe (80% to 99%), preocclusive, or occluded. Progression was defined as an increase in ICA stenosis to >/=50% for carotid arteries with a baseline of <50% or as an increase to a higher category of stenosis if the baseline stenosis was >/=50%. The Cox proportional hazards model was used for data analysis. RESULTS: The risk of progression of ICA stenosis increased steadily with time (annualized risk of progression, 9.3%). With multivariate modeling, the four most important variables that affected the progression (P <.02) were baseline ipsilateral ICA stenosis >/=50% (relative risk [RR], 3.34), baseline ipsilateral ECA stenosis >/=50% (RR, 1.51), baseline contralateral ICA stenosis >/=50% (RR, 1.41), and systolic pressure more than 160 mm Hg (RR, 1. 37). Ipsilateral neurologic ischemic events (stroke/transient ischemic attack) occurred in association with 14.0% of the carotid arteries that were studied. The progression of ICA stenosis correlated with these events (P <.001), but baseline ICA stenosis was not a significant predictor. CONCLUSION: In contrast to recently published studies, we found that the risk of progression of carotid stenosis is substantial and increases steadily with time. Baseline ICA stenosis was the most important predictor of the progression, but baseline ECA stenosis also was identified as an important independent predictor. Contralateral ICA stenosis and systolic hypertension were additional significant predictors. We found further that the progression of ICA stenosis correlated with ischemic neurologic events but not baseline stenosis. The data provide justification for the use of serial duplex scans to follow carotid stenosis and suggest that different follow-up intervals may be appropriate for different patient subgroups.

Transcutaneous interruption of ultrasound contrast agents for blood flow evaluation.

RATIONALE AND OBJECTIVES: The ability to create short boluses in targeted arteries with rapid rise times is limited by the transport of bubbles from the venous to arterial portion of the circulation. Acoustic interruption of contrast agent in arteries may create the short boluses necessary for simple wash-in/wash-out measures of blood flow. METHODS: An ultrasound contrast agent was used with spectral Doppler ultrasound to observe contrast interruption in femoral arteries and VX2 carcinoma in a rabbit model. At an upstream location in the femoral artery, single, sinusoidal ultrasound tone bursts at 1.8 MHz with durations of 0.25 to 1 seconds were applied to interrupt the flow of contrast agent injected intravenously. RESULTS: In VX2 carcinoma, bursts as short as 40 cycles produced contrast interruption lasting only one cardiac cycle within the tumor periphery and I(SPPA) <3 W/cm2 produced measurable interruptions. CONCLUSIONS: Acoustic fields applied transcutaneously interrupted flow of contrast agents to form temporally short negative boluses.

The experience of an academic medical center with endovascular treatment of abdominal aortic aneurysms.

BACKGROUND: Endovascular repair of abdominal aortic aneurysms (AAA) is gaining momentum although it is not yet approved in the United States by regulatory agencies. The Endovascular Grafting System (EGS), the first device to enter clinical trials in 1993, is now in phase III testing. METHODS: We reviewed the first 50 patients to undergo an EGS repair of AAA over 24 months at our institution. Results were compared with 69 patients who underwent open repair during the same time period by the same surgeon. RESULTS: Devices were successfully implanted in 47 of 50 (94%) patients. Three were converted to standard repair. Although length of stay was shorter, costs were similar. Follow-up was 3 to 24 months. Perigraft flow was noted in 33% at discharge; 73% of those stopped either spontaneously or with coiling. Three graft limbs occluded, requiring thrombolytic therapy. CONCLUSIONS: The EGS repair of AAA is feasible and effective. Cooperation between surgery and radiology is important for the success of a new endovascular program.

Glucocorticoid receptors are differentially expressed in the cells and tissues of the immune system.

Cytosolic glucocorticoid receptor (GR) binding studies on immune tissues demonstrate that the thymus exhibits three to four times higher levels of GR protein than the spleen. High levels of GR are consistent with the exquisite sensitivity of the thymus to glucocorticoid exposure. Nevertheless, whole cell binding studies reveal similar levels of GR in immature thymic T lymphocytes and more mature, splenic T lymphocytes. Moreover, whole cell binding techniques indicate that neutrophils (which represent roughly 30% of splenic leukocytes) exhibit higher GR than both T and B lymphocytes, further contradicting results from cytosolic binding studies. To address these inconsistencies, GR protein was assessed in immune cells and tissues using cytosolic radioligand binding. Western blot analysis, and immunocytochemistry. Consistent with previous cytosolic receptor binding studies on immune tissue homogenates, thymic T cells were found to have higher levels of GR than T cells isolated from the spleen. In addition, neutrophils were found to have fewer GR than lymphocytes and monocytes. These results indicate a meaningful relationship between receptor expression and known sensitivity to glucocorticoids.

Left atrial myxoma with embolization presenting as an acute infrarenal aortic occlusion.

We present the case of a 42-year-old woman who had acute total infrarenal aortic occlusion resulting from embolic implantation from a left atrial myxoma. We propose that the small aortic aneurysm that was discovered and repaired in this case may be a direct result of invasion and destruction of the aortic elastic laminae by implanted myxomatous tissue originating in the primary atrial tumor. This behavior has been noted in small vessels of the cerebrum and upper extremities with this lesion, but no prior reports of this occurrence in the aorta has been noted after extensive review of the literature.

An arginine analog inhibits responses of both the endothelium and smooth muscle of canine in situ vein grafts.

Increased shear, pressure, and oxygen tension in vein grafts may alter production of endothelium-derived vasoactive and anti-mitogenic factors such as nitric oxide which subsequently affect development of neointimal hyperplasia. This study was designed to determine whether or not nitric oxide mediates endothelium-dependent responses in femoral in situ vein grafts. Non-reversed, canine femoral vein grafts were placed bilaterally to bypass a ligated segment of the femoral artery in dogs. After 6 weeks, the grafts were removed, cut into rings, and suspended in organ chambers for measurement of isometric force. In some rings the endothelium was removed deliberately. In the presence of indomethacin, the synthetic analog of L-arginine, L-N(G)-monomethyl-arginine (10(-4) M; L-NMMA) did not cause a significant change in baseline tension of rings with endothelium. L-NMMA reduced only contractions of rings with endothelium to the alpha-adrenergic agonist UK 14,304. The analog also reduced maximal relaxations to the calcium-ionophore, A23187 in rings with endothelium. In addition, L-NMMA reduced relaxations of rings without endothelium to adenosine diphosphate by 35%. Positive immunostaining for nitric oxide synthase was present in both the myointima and media of histological sections of grafts. In conclusion, these results suggest that in situ vein grafts exhibit two unique properties which are unlike unoperated arteries or veins: (i) alpha2-adrenergic receptors may be coupled to the release of contractile endothelium-derived factors associated with production of nitric oxide: and (ii) nitric oxide may be released by the smooth muscle in response to purinergic stimulation. The presence of nitric oxide synthase throughout the wall of the graft may result in production of nitric oxide in response to adenosine diphosphate released by platelets and to circulating catecholamines.

Mesenteric venous thrombosis.

MVT is an uncommon form of visceral ischemia. Symptoms and signs of MVT are usually nonspecific and should not be relied on for accurate diagnosis. A simple, logical diagnostic algorithm can be used to manage most of these patients (Fig. 6). CT or MRI appears to be the most sensitive diagnostic test and should be obtained early for any patient suspected of harboring MVT. Patients with peritonitis require prompt abdominal exploratory laparotomy to rule out ischemic bowel. Once the diagnosis of acute MVT is confirmed, the patient should be anticoagulated with heparin. During operation, all nonviable bowel should be resected with intent for a second-look laparotomy after 24 hours if there is any question of ongoing ischemia. We recommend using fluorescein-assisted evaluation of marginally viable bowel intraoperatively. After the operation, anticoagulation is continued with heparin and then oral warfarin sodium when the patient's bowel function returns. For those patients without peritonitis, we recommend prompt anticoagulation followed by at least a 48- to 72-hour period of close observation. All patients who have had an episode of acute MVT and do not have a contraindication to anticoagulation should be anticoagulated on a life-long basis with warfarin sodium. Despite our increased awareness of acute MVT, the 30-day mortality rate remains high. Acute MVT typically has a more insidious and unpredictable course than do other forms of visceral ischemic syndromes, with a mortality rate as high as that of its arterial counterpart. Although there has been a slight improvement in survival during the last 20 years, the recurrence rate remains high and the long-term prognosis is poor in this group of patients. Survival of patients with chronic MVT is better than that of those with acute MVT and appears to be determined by the underlying disease.

Utility of clinical pathway and prospective case management to achieve cost and hospital stay reduction for aortic aneurysm surgery at a tertiary care hospital.

PURPOSE: We reviewed our experience with a clinical pathway instituted in December 1993 for all nonurgent abdominal aortic aneurysm (AAA) surgery. METHODS: We analyzed a reference group of 49 consecutive pre-pathway AAA patients (group I) and the 44 patients enrolled in the first year of the pathway (group II). On the basis of the interim review of data collected during the first year, pathway modifications were made, and 34 patients enrolled after these modifications (group III) were also analyzed. RESULTS: Comparison of groups I and II showed that institution of the pathway resulted in a marginally significant reduction in mean charges of 14.7% (p = 0.09), and a slight fall in mean length of stay (LOS) (13.8 vs 13.1 days, NS) and mortality rate (4.1% vs 2.3%, NS). For group II, a significant correlate (p < 0.05) of increased charges was fluid overload as diagnosed by chest radiograph. This recognition led to active efforts to reduce perioperative fluid administration. Comparison of groups II and III revealed that the practice modifications led to marked reduction in the incidence of fluid overload (73% vs 24%; p < 0.01), mean charges (30.4% reduction; p < 0.05), mean LOS (13.1 vs 10.2 days; p < 0.05), and median LOS (11 vs 8 days). Multiple regression analysis of all pathway patients showed that preoperative renal insufficiency is a significant predictor of both increased LOS (p < 0.01) and charges (p < 0.01), but that age, sex, and coronary disease were not predictive. Of the postoperative parameters analyzed, important correlates of increased charges were acute renal failure (p < 0.01) and fluid overload (p < 0.01). CONCLUSIONS: Institution of a clinical pathway for AAA repair resulted in significant charge reduction and a slight reduction in stay. Practice modifications based on interim data analysis yielded further significant reductions in charges and LOS, with overall per-patient charge savings (group I vs III) of 40.6% (p < 0.05) and overall LOS reduction of 3.5 days (p < 0.05). The reduction in actual charges was seen despite an overall increase in the hospital rate structure. Comparing groups I, II, and III, we found no indication of increasing mortality rate. Ongoing analysis has identified correlates of increased charges, potentially permitting identification of high-cost subgroups and more focused cost-control efforts. Rather than restricting management, clinical pathways with periodic data analysis may improve quality of care.