Steal syndrome complicating hemodialysis access procedures: can it be predicted?

The development of steal syndrome distal to an arteriovenous fistula (AVF) created for hemodialysis access remains a significant clinical problem. This study was undertaken to determine the role of intraoperative noninvasive testing in the prediction and management of steal syndrome following arteriovenous fistula creation. First, in order to determine a threshold digital/brachial index (DBI) for patients at risk for steal syndrome, we performed a retrospective review of patients who had had the DBI measured and who developed symptoms (steal syndrome) following AVF creation. This was followed by a prospective evaluation of the ability of the DBI to predict which patients undergoing AVF surgery would develop steal syndrome. A DBI of <0.6 identifies a patient at risk for steal syndrome. Intraoperative DBI cannot be used to predict which patient will develop steal syndrome; however, if revision is indicated, the DBI should be increased to >0.6. Failure to accomplish this puts the patient at risk for continued steal syndrome.

Subfascial perforator vein ablation: comparison of open versus endoscopic techniques.

PURPOSE: To compare the outcomes and complications of open (OSPS) versus endoscopic subfascial perforator surgery (SEPS) for treatment of chronic venous insufficiency. METHODS: Data were retrospectively collected on 25 patients who underwent 27 SEPSs from February 1996 to August 1997 and from 22 patients who underwent 29 OSPSs between March 1978 and May 1993. Outcomes were evaluated for postoperative complications, ulcer healing, recurrence, and venous dysfunction scores on the last follow-up for the SEPS group and at 1-year follow-up for the OSPS group. RESULTS: The 2 groups were similar in age, sex, history of previous venous surgery, healed or active ulcers, etiology, deep venous incompetency, pathophysiology, and venous refill times. Eighteen (90%) of 20 active ulcers in the SEPS group healed with recurrences in 5 (28%) limbs at 7.5 +/- 5.4-month follow-up. All 19 ulcers in the OSPS group healed, with recurrences in 13 (68%) limbs at 35 +/- 35-month follow-up. Clinical venous dysfunction scores showed significant improvement following SEPS (10.0 +/- 3.6 to 5.4 +/- 4.1, p < 0.001) and OSPS (10.0 +/- 3.2 to 6.7 +/- 3.6, p < 0.001) with no significant difference between groups. Both groups also had significant improvement in anatomical and disability scores. There was no postoperative mortality in either group. The OSPS group had significantly more wound complications (45%) than the SEPS group (7%) (p < 0.005). The hospital stay and readmission rate for wound problems were also higher in the OSPS group. CONCLUSIONS: The early outcome showed equal improvement in clinical venous dysfunction scores in the 2 groups, but with significantly fewer complications in the SEPS group. Although the long-term durability of the endoscopic approach has not been determined, the short-term results would favor SEPS for treatment of severe venous insufficiency when perforator incompetence is a significant component.

Duplex directed caval filter insertion in multi-trauma and critically ill patients.

This study was undertaken to determine the safety and feasibility of inferior vena cava (IVC) filter insertion at the bedside using duplex imaging in multi-trauma and/or critically ill patients. From February 1996 to August 1997, 53 multi-trauma and/or critically ill patients, who were in the intensive care unit and referred for an IVC filter, were prospectively evaluated for possible duplex directed caval filter (DDCF) insertion. Screening IVC duplex scans were performed in all patients. Satisfactory ultrasound visualization in 46 patients (87%) allowed attempted DDCF insertion. All procedures were percutaneously performed at the bedside using Vena Tech IVC filters. The results from this series showed that DDCF insertion can be safely and rapidly performed at the bedside in multi-trauma or critically ill patients. The procedure is dependent on satisfactory visualization of the IVC by duplex ultrasonography, which was possible in 45 out of 53 (85%) patients. Insertion at the bedside substantially reduces the procedural cost and avoids the need for transport, radiation exposure, and intravenous contrast.

Hematuria from arteriovesical fistula: unusual presentation of ruptured iliac artery aneurysm.

Iliac artery aneurysm rupture can be rapidly fatal if not diagnosed immediately. These aneurysms usually present in patients with other aneurysmal diseases of the aortoiliac arterial system. If not diagnosed and surgically repaired, iliac artery aneurysms can proceed to expand and ultimately rupture, usually presenting with back, flank, or abdominal pain and, possibly, signs of systemic shock. We present an unusual case report of a common iliac artery aneurysm rupture presenting as gross hematuria due to an arteriovesical fistula. Only three other cases of arteriovesical fistulae have been reported previously. Unlike the case presented, all three of these cases involved trauma or surgical instrumentation or manipulation of the bladder.

Endoleak after aortic stent graft repair: diagnosis by color duplex ultrasound scan versus computed tomography scan.

PURPOSE: The purpose of this study was to compare the accuracy of a color duplex ultrasound scan (CDU) to a computerized axial tomography scan (CT) in the diagnosis of endoleaks after stent graft repair of abdominal aortic aneurysms. METHODS: The Endovascular Aneurysm Clinical Trial Core Laboratory records were reviewed from 117 concurrent CDU and CT studies that were performed in 79 patients who were implanted with the Endovascular Technologies stent graft device between December 1995 and January 1997. All of the studies were interpreted by the Core Laboratory as having the presence or the absence of an endoleak or as being indeterminate because of technical factors. Of the 117 videotaped CDU studies available for reexamination, 100 were reassessed for technical adequacy on the basis of the following criteria: a satisfactory imaging of the aneurysm sac and of the stent graft with gray scale, and both color and spectral Doppler scan evaluation for endoleak outside the endograft and within the aneurysm sac. RESULTS: Of the 117 studies, 103 CDUs (88%) and 114 CTs (97%) were recorded as having the presence or the absence of an endoleak and 14 CDUs (12%) and 3 CTs (3%) were indeterminate. For the studies that were recorded to have the presence or the absence of an endoleak, the sensitivity, the specificity, the positive and the negative predictive values, and the accuracy of CDUs as compared with CTs were 97%, 74%, 66%, 98%, and 82%, respectively. Of the 100 CDU videotaped studies available for review, the following results were seen: (1) 93 CDUs had satisfactory B-mode images, (2) 76 had satisfactory color Doppler scan images to evaluate for endoleaks, (3) 55 had color Doppler scan assessment of the entire abdominal aortic aneurysm sac for endoleak, and (4) 27 had spectral Doppler scan waveform confirmation of suspected endoleaks. Only 19 CDU studies (19%) with all 4 criteria for complete assessment of endoleak were performed. CONCLUSION: Although most of the CDU studies were technically suboptimal, the CDUs reliably identified endoleaks with an excellent sensitivity and a negative predictive value as compared with CT scans.

A comparison of surgery for neurogenic thoracic outlet syndrome between laborers and nonlaborers.

OBJECTIVE: To determine factors of outcome following surgical intervention for neurologic thoracic outlet syndrome (NTOS). METHODS: In a retrospective study of patients surgically treated for NTOS, outcome was evaluated by postoperative symptoms and the ability of patients to return to work. RESULTS: Good, fair, and poor results were obtained in 26 (48%), 21 (39%), and 7 (13%) patients, respectively. The best predictor of a good outcome was occupation. Nonlaborers were more likely to have good outcome (21 of 32, 66%) when compared with laborers (5 of 22, 23%; P = 0.0025). Only 6 of 20 (30%) laborers were able to return to their original occupation compared with 17 of 26 (65%) nonlaborers (P = 0.036). CONCLUSIONS: Laborers with NTOS are less likely to have a good result from surgical intervention, are unlikely to return to their original occupation, and may require retraining for a non-labor-intensive occupation if they cannot return to their original work.

Management of renal trauma at a rural, level I trauma center.

Appropriate management of renal trauma is controversial. Successful outcome and long term complication rates are not well defined. In an effort to evaluate management options, outcomes, and complications of renal injuries, we conducted a retrospective review of all trauma patients admitted to the trauma service from January 7, 1989 through August 31, 1995. Inpatient and outpatient charts were reviewed for type and mechanism of injury, radiologic studies utilized, method of treatment, and short and long term complications. Fifty-five patients were identified with renal injuries. Most injuries were parenchymal injuries due to blunt trauma. Only nine patients with renal artery injuries and four patients with collecting system injuries were identified. CT scan was the most commonly used study to identify renal injuries. All nine renal artery injuries were due to blunt trauma and were initially diagnosed by CT scan. Six were confirmed with arteriogram, and two with renal scans. Of the seven patients seen in follow-up (average 153 days), there were three complications: one patient with small bowel obstruction and two patients with hypertension. Among the 47 patients with parenchymal injuries, including 4 patients with collecting system injuries, there were 2 with complications: an intraoperative ureteral transection and a urinoma. Both complications were treated successfully with a ureteral stent. Five deaths occurred in the entire group; none were related to renal injury. Thirteen patients underwent laparotomy for associated injuries only. Eight patients underwent surgical treatment for their renal injury, including five nephrectomies. The nephrectomy rate among those patients who underwent laparotomy as part of their initial management was 20 per cent, versus 3 per cent for those patients initially managed nonoperatively. Thus, most renal injuries can be managed nonoperatively with a low incidence of complications. The incidence of long-term complications after renal artery injuries and the appropriate management of these patients deserves further study.

Postinjury thromboxane receptor blockade ameliorates acute lung injury.

BACKGROUND: Acute lung injury is associated with pulmonary hypertension, intrapulmonary shunting, and increased microvascular permeability, leading to altered oxygenation capacity. Thromboxane A2 has been found to be a central mediator in the development of septic and oleic acid (OA)-induced acute lung injury. Our previous study demonstrated a beneficial effect of preinjury thromboxane A2 receptor blockade. The current study examines the efficacy of postinjury receptor blockade on oxygenation capacity and pulmonary hemodynamics in an isolated lung model of OA-induced acute lung injury. METHODS: Four groups of rabbit heart-lung preparations were studied for 60 minutes in an ex vivo perfusion-ventilation system. Saline control lungs received saline solution during the first 20 minutes of study. Injury control lungs received an OA-ethanol solution during the first 20 minutes. Two treatment groups were used: T10, in which the thromboxane receptor antagonist, SQ30741, was infused 10 minutes after the initiation of OA infusion; and T30, in which the thromboxane receptor antagonist was infused 30 minutes after OA infusion. RESULTS: Significant differences were found in oxygenation (oxygen tension in T10 = 62.6 +/- 11.7 mm Hg, T30 = 68.2 +/- 21.2 mm Hg; injury control = 40.2 +/- 9.0 mm Hg, saline control = 123.5 +/- 16.01 mm Hg; p < 0.001) and percentile change in pulmonary artery pressure (T10 = 1.1% +/- 19.4% increase, T30 = 11.2% +/- 7.3% increase; injury control = 47.6% +/- 20.5%, saline control = 4.2% +/- 6.81%; p < 0.001). CONCLUSIONS: This study demonstrates that blockade of the thromboxane A2 receptor, even after the initiation of acute lung injury, eliminates pulmonary hypertension and improves oxygenation.

Thromboxane receptor blockade improves oxygenation in an experimental model of acute lung injury.

BACKGROUND: Adult respiratory distress syndrome remains a major cause of morbidity and mortality. We investigated the role of thromboxane receptor antagonism in an experimental model of acute lung injury that mimics adult respiratory distress syndrome. METHODS: Three groups of rabbit heart-lung preparations were studied for 30 minutes in an ex vivo blood perfusion/ventilation system. Saline control (SC) lungs received saline solution during the first 20 minutes of study. Injury control (IC) lungs received an oleic acid-ethanol solution during the first 20 minutes. Thromboxane receptor blockade (TRB) lungs received the same injury as IC lungs, but a thromboxane receptor antagonist (SQ30741) was added to the blood perfusate just prior to study. Blood gases were obtained at 10-minute intervals, and tidal volume, pulmonary artery pressure, and lung weight were continuously recorded. Oxygenation was assessed by measuring the percent change in oxygen tension over the 30-minute study period. Tissue samples were collected from all lungs for histologic evaluation. RESULTS: Significant differences were found between SC and IC lungs as well as TRB and IC lungs when comparing pulmonary artery pressure (SC = 33.1 +/- 2.2 mm Hg, TRB = 35.4 +/- 2.1 mm Hg, IC = 60.4 +/- 11.1 mm Hg; p < 0.02) and percent change in oxygenation (SC = -20.6% +/- 10.3%, TRB = -24.2% +/- 9.5%, IC = -57.1% +/- 6.2%; p < 0.03). None of the other variables demonstrated significant differences. CONCLUSIONS: Thromboxane receptor blockade prevents the pulmonary hypertension and the decline in oxygenation seen in an experimental model of acute lung injury that mimics adult respiratory distress syndrome.

Nonoperative management of blunt hepatic trauma.

Abdominal CT scanning makes nonoperative management of liver injury possible. We reviewed medical records of 56 blunt trauma patients with hepatic injury who received initial abdominal CT scan. We examined: 1) Indications for delayed surgery; 2) Disposition or cause of death; 3) Results of follow up CT scans; 4) Long term complications. Over a 53 month period, 1597 patients were admitted for blunt trauma, of which 76 patients were found to have hepatic injury. Twenty patients presented either clinically unstable or with an acute abdomen and underwent diagnostic peritoneal lavage or immediate laparotomy without a CT scan. Abdominal CT scan was performed on 56 patients, 19 of whom had hepatic injury or associated major abdominal injury and underwent laparotomy. One patient died of cardiac arrhythmias following CT scanning. The remaining 36 patients received initial nonoperative management of their hepatic injury. Three patients in this group underwent delayed abdominal surgery. Two developed an acute abdomen. One had a planned nephrectomy. No patient required surgical treatment of their liver injury at the time of laparotomy. Four deaths occurred in the 36 patients managed nonoperatively, all due to associated extra-abdominal injuries. Nineteen patients had 27 CT scans taken as follow up examination at intervals of 1 to 94 days postinjury. All of the CT scans showed stabilization or improvement of hepatic injury. Three patients who had CT scans taken at 3 months postdischarge were asymptomatic, with radiologic resolution of their hepatic injury. Nineteen patients were followed for an average of 61.8 days (range 7-203 days) after discharge with no complications from liver injury.(ABSTRACT TRUNCATED AT 250 WORDS)