Prospective radial artery study following induction of reactive hyperemia looking at degree of diameter growth in healthy subjects.

OBJECTIVES: This "proof of concept" study sought to determine the magnitude of radial artery diameter change in 20 healthy subjects by induction of flow mediation dilatation (FMD) via reactive hyperemia. BACKGROUND: Transradial access in the cardiac catheterization laboratory is becoming more commonplace due to lower bleeding complications and increase in patient comfort. However, access to the radial artery can be challenging due to small vessel size. We sought to examine whether FMD can be used to increase radial artery diameter, potentially allowing improved transradial access. METHODS: We obtained baseline radial artery diameter via a high frequency ultrasound probe on 20 healthy subjects. A standard reactive hyperemia protocol was employed in the right arm, followed by successive measurements of the subject's radial artery at pre-specified intervals. Radial artery diameter measurements were performed offline by the sonographer and also a blinded reader to which agreement was sought. RESULTS: We found a mean increase in radial artery size of 0.48 ± 0.13 mm at peak reactive hyperemic states. This correlated to a mean increase in overall radial artery diameter of 21.7 ± 6.7%. The median time to peak dilation was 30 seconds (95% CI; 15-45 seconds), and the median duration of maximal dilation was 60 seconds (95% CI; 45-75 seconds). CONCLUSIONS: Among healthy subjects, we demonstrated a mean maximal increase in radial artery diameter of 21.7 ± 6.7% via FMD. This finding supports the notion that radial artery diameter can be increased noninvasively via a reactive hyperemia protocol.

Predictors of mortality after muscle flap advancement for deep sternal wound infections.

BACKGROUND: Deep sternal wound infection is a devastating complication following median sternotomy, with mortality rates reported from 1.0 to 36 percent. Several studies have evaluated the risk factors for the development of a deep sternal wound infection, but the factors predicting survival after debridement and muscle flap advancement are not well known. METHODS: A retrospective chart review was performed from September of 1997 to January of 2004 on all patients referred to a single plastic surgeon for treatment of a deep sternal wound infection following median sternotomy for cardiovascular surgery. The authors collected cardiovascular operative and intensive care unit data and information regarding patient demographics, medical history, laboratory studies, and follow-up. Data were analyzed as possible prognostic factors. RESULTS: During the collection period, a total of 8414 cardiovascular surgery cases were performed through a median sternotomy. Deep sternal wound infections were identified and treated with muscle flap advancement in 124 patients (1.5 percent). Most patients (90 percent) were treated with bilateral pectoralis major flap advancements. Eighty-five patients underwent debridement and muscle flap advancement as a single-stage procedure. There were 26 perioperative deaths (21 percent). Presternotomy end-stage renal disease, presternotomy chronic obstructive pulmonary disease, and prolonged poststernotomy mechanical ventilation were found to be significant independent predictors of mortality despite muscle flap advancement. CONCLUSIONS: These data identify patients with deep sternal wound infections who may be at increased risk for mortality after debridement and muscle flap advancement. This information may help the patient, family, and surgeon modify medical management or surgical treatment of this devastating problem.

Predictors of mortality in trauma patients with intracranial hemorrhage on preinjury aspirin or clopidogrel.

BACKGROUND: The mortality risk in elderly patients who sustained head trauma resulting in intracranial hemorrhage (ICH) while taking the antiplatelet agents aspirin (ASA) or clopidogrel or both (Plavix) was evaluated. METHODS: A retrospective review identified trauma patients, age 50 or greater, who had computed tomography (CT) evidence of ICH and were taking ASA, clopidogrel, or a combination of both. Patient demographics, type of medication, mechanism of injury, Glasgow Coma Score (GCS), grading of head CT scans, and outcomes were characterized. RESULTS: One hundred nine patients including 61 men and 48 women were identified; the mean age was 77 years +/- 10 years. Injury was due to level fall (73), fall from height (21), motor vehicle crash (11), and other (4). Twenty (18%) patients died; age, gender, type of medication, and mechanism of injury were not predictive of death. The initial GCS for survivors was 14.2 +/- 1.9 versus 11.3 +/- 4.9 for nonsurvivors (p < 0.007). Deaths based on initial CT grade were: grade 1, 5 of 70; grade 2, 4 of 17; grade 3, 5 of 10; grade 4, 6 of 12 (p = 0.002). Follow-up CT scans were performed in 81 patients who were not taken to surgery and had grade 1 or 2 hemorrhage initially. Of 4 patients with hemorrhage progression, there was 1 death (25%) versus 6 deaths in 77 patients without progression (8%; p = 0.70). CONCLUSIONS: There is high mortality rate associated with ASA or clopidogrel or both in elderly patients who have head trauma resulting in ICH. The presenting GCS and initial grade of CT scan are most predictive of death. Progression of hemorrhage after admission is unusual. The risk of brain injury, particularly from falls, should be explained to elderly patients taking these medications.

Contemporary outcomes for carotid endarterectomy at a large community-based academic health center.

The North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Asymptomatic Carotid Atherosclerosis Study (ACAS) demonstrated the efficacy of carotid endarterectomy (CEA), but these studies were published 15 and 11 years ago, respectively. We hypothesized that present clinical results of CEA have improved compared with those reported by NASCET/ACAS. Every patient having CEA from January 1999 through December 2003 was reviewed as part of a continuous quality-assurance program. Patient demographics and risk factors were recorded; high-risk patients were identified using inclusion criteria for high-risk carotid stent trials. Primary end points recorded were all neurologic events, deaths, and myocardial infarctions (MIs). Outcomes were reported individually or as combined neurologic events and deaths (traditional NASCET/ACAS methodology) and, similar to recent carotid stent trials, individually, combined, and as a composite that included MI. A total of 1,927 CEAs were performed, 1,140 in men (59%) and 787 in women (41%). The average age was 72 +/- 9 years; 21% of patients were age 80 or older. Symptomatic patients accounted for 717 procedures (37%). Perioperative neurologic event, death, and MI occurred in 1.0%, 0.5%, and 1.3% of patients, respectively. The combined neurologic event and death rate was 1.3% (symptomatic = 1.8%, asymptomatic = 1.1%). High-risk patients comprised 54% of the cohort; the neurologic event and death rate for this group was 1.6%. The composite end point including MI was 3.4%. Severe coronary artery disease and prior ipsilateral CEA significantly correlated with a higher incidence of primary end point complications. In contemporary practice, the perioperative neurologic event rate is significantly less than reported in NASCET/ACAS. Perioperative death and MI rates were similar to those seen in NASCET/ACAS. Neurologic events and death rates were not different between high- and low-risk groups. These data may serve as a guide for the modern vascular specialist weighing open and endovascular options for treatment of carotid artery occlusive disease in both high- and low-risk patients.

Treatment of trauma patients with intracranial hemorrhage on preinjury warfarin.

BACKGROUND: Preinjury warfarin anticoagulation has been shown to increase the mortality of traumatic intracranial hemorrhage. We have evaluated the impact on patient mortality of the rapid triage of patients at risk for warfarin associated traumatic intracranial hemorrhage. METHODS: A "Coumadin Protocol" was implemented in January, 2001 in the Emergency Department that expedited triage of anticoagulated trauma patients to immediate physician evaluation. Patient outcomes during a 2 year period were compared with a matched control group of similarly injured, anticoagulated patients who were treated before protocol initiation. RESULTS: Thirty-five patients were treated after implementation of the Coumadin Protocol. Mean time until warfarin reversal was 4.3 +/- 4.4 hours, and there was a 37% mortality. Twenty-two control patients had a mean time to reversal of 4.2 +/- 2.9 hours, with a 45% mortality (p = 0.610). Ten protocol patients were shown to have intracranial hemorrhage progression by computed tomography (CT) scan, with a 60% mortality rate. Seventeen patients had follow-up CT scan and showed no progression; only one of these patients (6%) died (p = 0.004). Hemorrhage severity based on the initial CT scan did not predict mortality or hemorrhagic progression. CONCLUSIONS: We conclude from these data that a trauma center protocol for rapid identification of intracranial bleeding without a concomitant therapeutic protocol does not improve survival in head injured patients on preinjury warfarin.

Positron-emission tomography as a prognostic tool for early-stage lung cancer.

BACKGROUND: Positron-emission tomography (PET) shows tissue metabolic activity in the form of the standard uptake value (SUV). This study examines the prognostic value of the SUV for early-stage lung cancer. METHODS: A retrospective review of 187 patients undergoing PET for potential lung cancer. Data collected included patient demographics, tumor pathology, and survival information. Data were correlated with PET results to determine if a prognostic relationship exists. RESULTS: The sensitivity and specificity of PET for detecting malignant lesions were 98% and 24%. Malignant lesions had a higher SUV than benign lesions (5.9 +/- 6.2 versus 2.2 +/- 1.8, P < .0001). The average SUV of well-differentiated tumors was 2.6 +/- 3.1 versus 5.9 +/- 5.5 for other tumors (P = .010). There was a strong correlation between tumor stage and SUV (analysis of variance, P < .0001). There was no difference in tumor SUV for survivors versus nonsurvivors. CONCLUSIONS: The SUV correlates with prognostic indicators, such as tumor stage and grade. The SUV alone was not an independent predictor of survival.

Rapid warfarin reversal in anticoagulated patients with traumatic intracranial hemorrhage reduces hemorrhage progression and mortality.

BACKGROUND: A prospective cohort study at our institution demonstrated a 48% mortality rate in warfarin anticoagulated trauma patients sustaining intracranial hemorrhage (ICH) compared with a 10% mortality rate in nonanticoagulated patients. Forty percent of patients demonstrated progression of their ICH, despite anticoagulation reversal, with a resultant 65% mortality rate. Seventy-one percent of these patients initially presented with a Glasgow Coma Scale (GCS) score > or = 14 and a 'minor' ICH. We postulated that early diagnosis of ICH and rapid anticoagulation reversal would reduce ICH progression rates and mortality. METHODS: All anticoagulated patients with known or suspected head trauma were entered into the Coumadin protocol. The protocol ensured immediate triage and physician evaluation, head computed tomography (CT) scan, and fresh frozen plasma administration in patients with documented ICH. RESULTS: Eighty-two patients were entered into the protocol with ICH documented in 19 (23%). Sixteen of 19 patients (84%) presented with GCS > or = 14. Median international normalized ratio (INR) for treated patients with ICH was 2.7 versus 2.5 for patients without ICH (p = 0.546). Mean time to initiate warfarin reversal was 1.9 hours for protocol patients versus 4.3 hours for preprotocol patients (p < 0.001). Two of 19 (10%) protocol patients with ICH died. However, both patients presented >10 hours after injury with a severe ICH. This 10% mortality rate is significantly less than the 48% mortality rate seen previously (p < 0.001) and is now consistent with that observed in similarly injured patients not on anticoagulation. CONCLUSION: Neither the initial GCS nor INR in anticoagulated trauma patients reliably identifies patients with ICH. Rapid confirmation of ICH with expedited head CT scan combined with prompt reversal of warfarin anticoagulation with fresh frozen plasma decreases ICH progression and reduces mortality.

A randomized, prospective, double-blind, placebo-controlled trial of the effect of a calcium channel blocker ointment on pain after hemorrhoidectomy.

PURPOSE: Spasm of the internal sphincter plays a role in hemorrhoidal disease and may be a source of anal pain after hemorrhoid surgery. We have evaluated the effects of topical diltiazem, a calcium channel blocker, in reducing pain after hemorrhoidectomy. METHODS: After hemorrhoidectomy, 18 patients were randomly assigned to receive 2 percent diltiazem ointment (n = 9) or a placebo ointment (n = 9). Ointments were applied to the perianal region three times daily for seven days. Patients were prescribed hydrocodone bitartrate (Vicodin) to take as needed. The type and number of prescribed or nonprescribed medications taken during the postoperative period were recorded. Patients maintained a log to measure postoperative pain daily and perceived benefit of the ointment, using a Visual Analog Scale ranging from 0 to 10. Any postoperative morbidity noted during the follow-up period was recorded. RESULTS: Patients using the diltiazem ointment had significantly less pain and greater benefit than those in the placebo group throughout the first postoperative week. Postoperative pain scores in the placebo group averaged 8.8 +/- 1.2 early and diminished to 5.2 +/- 1.7 at the end of one week, compared to the diltiazem group of 5.2 +/- 2.4 early and 2.3 +/- 1.2 at the end of one week (P < 0.001, both time periods). Perceived benefit in the placebo group averaged 2.7 +/- 1.2 vs. 5.6 +/- 1.4 in the diltiazem group (P < 0.001). Total and daily narcotic use was higher in the placebo group, but this was not statistically significant (P = 0.13). No differences in the frequency of use of nonsteroidal anti-inflammatory drugs and acetaminophen were seen between the two groups, and there were no differences in morbidity between the two groups. CONCLUSIONS: Perianal application of 2 percent diltiazem ointment after hemorrhoidectomy significantly reduces postoperative pain and is perceived as beneficial, with no increase in associated morbidity. Patients using a placebo ointment tend to take more prescription narcotics for pain relief postoperatively, with a similar usage of nonsteroidal anti-inflammatory drugs and acetaminophen, although differences were not significant.

Diagnosis of total internal carotid occlusions with duplex ultrasound and ultrasound contrast.

It remains a significant technical challenge for duplex ultrasound to accurately differentiate between total and near total internal carotid artery (ICA) occlusions. We have evaluated the efficacy of an ultrasound contrast agent combined with improved imaging techniques in patients with suspected carotid artery occlusions. Patients identified by conventional duplex ultrasound between January and August 2003 as having a possible ICA occlusion were eligible for study. A 1 mL bolus of ultrasound contrast agent was injected into a 50 mL bag of normal saline and given intravenously at a rate of approximately 4-5 mL/minute. Ultrasound imaging and spectral Doppler analysis were done using tissue harmonic imaging for optimum contrast agent to soft tissue discrimination, or with the direct B-mode imaging of blood flow to maximize the brightness of the circulating contrast agent. Ten patients were identified, 6 men and four women with a mean age of 68.3 years. Nine suspected total ICA occlusions were unilateral and 1 was bilateral. Imaging with contrast agent confirmed occlusion of the ICA in 7 of 10 patients; 3 patients had near-total occlusion with flow detected in the distal ICA by spectral and color Doppler. All 3 of these near-total occlusions were ultimately confirmed by either conventional or magnetic resonance carotid angiography. The contrast agent was most beneficial in improving the detection of minimal flow beyond a severe stenosis and in evaluating flow dynamics in the presence of severely calcified plaque. We conclude that the use of an ultrasound contrast agent with newer duplex ultrasound imaging techniques can reliably distinguish total from near-total internal carotid artery occlusions. Future prospective studies should be able to define the efficacy of ultrasound contrast agents in improving the overall diagnostic accuracy of duplex ultrasound in technically difficult cases and in patients with complex peripheral vascular disease.

Epidural versus intravenous pain control in elderly patients with rib fractures.

BACKGROUND: Epidural catheters are used in older patients with rib fractures to improve outcome. We reviewed the efficacy of epidural analgesia (EA) compared with intravenous narcotics (IVN) in this population. METHODS: Rib fracture patients >55 years old admitted to our level I trauma center from 1999 through 2002 were reviewed for demographics, Injury Severity Score (ISS), Abbreviated Injury Score for chest, length of stay, cardiopulmonary comorbidities, complications, and type of analgesia. RESULTS: There were 187 patients: 72 men and 115 women. The mean age was 77 years. For ISS <9, length of stay for EA patients was 12 +/- 5 days versus 5 +/- 4 days for IVN patients (P < 0.001). Complications occurred in 9 of 10 EA patients versus 21 of 52 IVN patients (P < 0.001). No difference was noted in length of stay for patients with ISS > or =9. Complications in the high ISS group occurred in 29 of 43 EA patients versus 37 of 82 IVN patients (P <0.05). Stratification of patients based on low versus high Abbreviated Injury Score for chest yielded similar results. CONCLUSIONS: EA is associated with prolonged length of stay and increased complications in elderly patients, particularly those with less significant injuries, regardless of cardiopulmonary comorbidities. EA for elderly patients with rib fractures should be prospectively re-evaluated.

Spontaneous retroperitoneal hemorrhage.

BACKGROUND: We evaluated patients with spontaneous retroperitoneal hemorrhage for reliable predictors of early diagnosis and improved outcomes. METHODS: A retrospective chart review was done to determine patient demographic and laboratory findings, presenting symptoms, time to diagnosis, anticoagulant and/or antiplatelet agent use, transfusions, and patient outcome. RESULTS: One hundred nineteen patients were identified; 14 (12%) died (mean age 77 +/- 9 years vs. 74 +/- 10 years for survivors [P = 0.235]). All nonsurvivors were on anticoagulants: 8 of 89 (9%) were on heparin or warfarin alone, and 6 of 23 (26% [P = 0.028]) were on a combined anticoagulant-antiplatelet regimen. Symptom onset to computed axial tomography (CAT) scan averaged 1.3 +/- 1.3 days for nonsurvivors versus 1.5 +/- 1.9 days for survivors (P = 0.778). Hemoglobin was 9.07 +/- 3.35 for nonsurvivors versus 9.60 +/- 2.07 for survivors (P = 0.435). Eighty-eight patients were transfused, and 10 died; 31 patients had no transfusion, and 4 of these died (P = 0.821). CONCLUSIONS: A high index of clinical suspicion is necessary for diagnosis of spontaneous retroperitoneal hemorrhage because these patients present with a variety of symptoms. Prospective studies are necessary to determine whether earlier diagnosis combined with aggressive resuscitation can impact the high mortality rate seen in these patients.

Nitric oxide-releasing biopolymers inhibit thrombus formation in a sheep model of arteriovenous bridge grafts.

OBJECTIVES: Nitric oxide (NO), produced by normal vascular endothelial cells, reduces platelet aggregation and thrombus formation. NO-releasing biopolymers have the potential to prolong vascular graft and stent patency without adverse systemic vasodilation. METHODS: 5-mm polyurethane vascular grafts coated with a polymer containing the NO-donor dialkylhexanediamine diazeniumdiolate were implanted for 21 days in a sheep arteriovenous bridge-graft model. RESULTS: Eighty percent (4/5) of grafts coated with the NO-releasing polymer remained patent through the 21 day implantation period, compared to fifty percent (2/4) of sham-coated grafts and no (0/3) uncoated grafts. Thrombus-free surface area (+/-SEM) of explanted grafts was significantly increased in NO-donor coated grafts (98.2% +/- 0.9%) compared with sham-coated (79.2% +/- 8.6%) and uncoated (47.2% +/- 5.4%) grafts ( P = .00046). Examination of the graft surface showed no adherent thrombus or platelets and no inflammatory cell infiltration in NO-donor coated grafts, while control grafts showed adherent complex surface thrombus consisting of red blood cells in an amorphous fibrin matrix, as well as significant red blood cell and inflammatory cell infiltration into the graft wall. CONCLUSION: In this study we determined that local NO release from the luminal surface of prosthetic vascular grafts can reduce thrombus formation and prolong patency in a model of prosthetic arteriovenous bridge grafts in adult sheep. These findings may translate into improved function and improved primary patency rates in small-diameter prosthetic vascular grafts.

Duplex ultrasound recognition of spontaneous carotid dissection--a case report and review of the literature.

Spontaneous dissection of the internal carotid artery is an uncommon entity with a variable clinical presentation. A high index of suspicion is required to make the diagnosis, and prompt diagnosis and treatment with anticoagulation are essential for improved patient outcomes. Duplex ultrasound provides a safe and reliable imaging modality for early diagnosis and follow-up. The authors present a case of spontaneous internal carotid artery dissection with duplex ultrasound findings and a review of the literature.

Management of blunt splenic injury in patients with concurrent infectious mononucleosis.

Selective nonoperative management is appropriate for most blunt splenic injuries in adults and children, but the efficacy of this approach is unknown when injury occurs in patients with concurrent infectious mononucleosis. We have reviewed our experience during the past 23 years with the selective nonoperative management of blunt splenic injury in these patients. Medical record review identified nine patients with blunt splenic injury and infectious mononucleosis from 1978 to 2001, representing 3.3 per cent of our total trauma population with blunt splenic injury treated during that interval. Two patients underwent immediate splenectomy because of hemodynamic instability. Seven patients were admitted with the intent to treat nonoperatively. Five patients were successfully managed nonoperatively. Two patients failed nonoperative management and underwent splenectomy, one because of hemodynamic instability and one because of an infected splenic hematoma. Concurrent infectious mononucleosis does not preclude the successful nonoperative management of blunt splenic injury. This small subset of patients may be managed nonoperatively using the same criteria as for patients whose splenic injuries are not complicated by infectious mononucleosis.

Lysyl oxidase expression in a rat model of arterial balloon injury.

OBJECTIVE: Traditional therapies for arteriosclerotic disease often fail as a result of an exaggerated fibroproliferative response (recurrent stenosis) at the site of the intervention. Lysyl oxidase, secreted by activated vascular smooth muscle cells and fibroblasts, catalyzes a key step in the cross-linking and stabilization of collagen and elastin in the vascular wall. We hypothesized that lysyl oxidase messenger RNA (mRNA) and protein expression are time-dependent and precede collagen accumulation and luminal narrowing after arterial balloon injury in the rat. METHODS: A 2F balloon-tipped catheter was used to injure the right common carotid artery in male Sprague-Dawley rats. Injured right and control (uninjured) left common carotid arteries were harvested at 0, 0.25, 1, 3, 7, 14, 21, 28, and 60 days for mRNA quantitation and immunohistochemical analysis. Steady-state lysyl oxidase mRNA levels were quantitated with real-time reverse transcription polymerase chain reaction (TaqMan). Immunohistochemical staining with antibodies to alpha-smooth muscle cell actin and lysyl oxidase, and Movat pentachrome staining were performed for qualitative assessment of changes in the cellular and extracellular matrix components of the vessel wall. Post-injury intimal area was measured from hematoxylin and eosin-stained specimens at each time point. RESULTS: When compared with sham-operated control arteries, lysyl oxidase expression in balloon-injured arteries increased significantly to 212% by day 3 after injury, and remained elevated through day 21, with a decrease toward baseline levels by day 28. Lysyl oxidase protein expression did not peak until day 14, and persisted through day 28. Collagen accumulation peaked at day 28, corresponding to the maximal increase in intimal area, with later accumulation of proteoglycans and ground substance in the intimal lesion. CONCLUSION: Our results indicate that lysyl oxidase mRNA and protein expression is time-dependent after balloon injury of the rat carotid artery and that expression appears to precede maximal collagen accumulation and corresponding increases in intimal area. This suggests that lysyl oxidase may have an important role in stabilization of collagen and elastin at sites of vascular injury and that modulation of lysyl oxidase activity may be a viable method to prevent or reduce recurrent stenosis. CLINICAL RELEVANCE: Failure of traditional therapies for ischemic arteriosclerotic disease is often due to an exaggerated fibroproliferative response (recurrent stenosis) at the site of intervention. Recurrent stenosis can be viewed as an injury-repair process, with an initial stage characterized by cellular proliferation followed by deposition of extracellular matrix. This study focuses on lysyl oxidase, a key enzyme involved in stabilization of collagen and elastin. This study demonstrates that lysyl oxidase messenger RNA and protein expression are time-dependent, preceding collagen accumulation and corresponding increases in intimal area. Accumulation of extracellular matrix is a major factor in growth of the restenotic lesion, and modulation of lysyl oxidase activity may offer a therapeutic method for decreasing or preventing recurrent stenosis.

Gastrointestinal complications following infrarenal endovascular aneurysm repair.

Gastrointestinal complications are known to occur after open elective aortic aneurysm repair. This leads to increased morbidity, mortality, length of stay, and hospital costs. The authors hypothesize a change in the character and/or frequency of early postoperative gastrointestinal complications after endovascular aneurysm repair as compared to open abdominal aortic repair. This is a retrospective cohort study in which the medical records of 153 consecutive patients who underwent endovascular infrarenal aneurysm repair from November 1998 to August 2001 were reviewed for gastrointestinal complications. Of these 153 patients, 9 (5.9%) had postoperative gastrointestinal complications. Three patients (1.9%) underwent exploratory laparotomy for small bowel obstruction. One patient had had a right hemicolectomy for cancer 2 years before stent graft placement. This patient needed a partial small bowel resection. One patient had had a right hemicolectomy 4 months before stent graft placement; he had lysis of adhesions with no bowel resection. A third patient underwent operative repair of an incarcerated inguinal hernia. Six patients (3.9%) had paralytic ileus that was treated by nasogastric tube or observation resulting in an extended hospital length of stay. All cases of ileus resolved without any operative intervention. No patients in this series developed any intestinal ischemia, pancreatitis, cholecystitis, or gastrointestinal bleeding. After endovascular aneurysm repair, gastrointestinal complications such as ileus and postoperative small bowel obstruction are seen with a similar frequency as after open aortic repair. This occurs despite the absence of a laparotomy with mesenteric dissection and evisceration. In this series, these complications are associated with longer hospital length of stay but no increased mortality rate. No instances of colonic ischemia, pancreatitis, cholecystitis, or gastrointestinal bleeding were seen in this series.

Hypothermia is an independent predictor of mortality in ruptured abdominal aortic aneurysms.

Hypothermia is known to significantly increase mortality in trauma patients, but the effect of hypothermia on outcomes in ruptured abdominal aortic aneurysms (RAAA) has not been evaluated. The authors reviewed their experience from 1990 to 1999 in 100 consecutive patients who presented with RAAA and survived at least to the operating room for surgical treatment. There were 70 men and 30 women, with a mean overall age of 74 +/-8 years. Overall mortality was 47%. Univariate ANOVA (analysis of variants) showed significant correlation with mortality for decreased intraoperative temperature, decreased intraoperative systolic blood pressure, increased intraoperative base deficit, increased blood volume transfused, increased crystalloid volume (all p < 0.001); decreased preoperative hemoglobin (p = 0.015); and increased age (p = 0.026). Patient sex, initial preoperative temperature, preoperative systolic blood pressure, and operating room time were not correlated with mortality in the univariate analysis. Using these same clinical variables, multiple logistic regression analysis showed only 2 factors independently correlated with mortality: lowest intraoperative temperature (p = 0.006) and intraoperative base deficit (p = 0.009). The mean lowest temperature for survivors was 35 +/-1 degrees C and for nonsurvivors 33 +/-2 degrees C (p < 0.001). When patients were grouped by lowest intraoperative temperature, those whose temperature was < 32 degrees C (n = 15) had a mortality rate of 91%, whereas patients with a temperature between 32 and 35 degrees C (n = 50) had a mortality rate of 60%. In the group that remained at or > 35 degrees C (n = 35) the mortality rate was only 9%. A nomogram of predicted mortality versus temperature was constructed from these data and showed that for temperatures of 36, 34, and 32 degrees C the predicted mortality was 15%, 49%, and 84%, respectively. The authors conclude that hypothermia is a strong independent contributor to mortality in patients with ruptured abdominal aortic aneurysms and that very aggressive measures to prevent hypothermia are warranted during the resuscitation and treatment of these patients.

Reliability of extracranial carotid artery duplex ultrasound scanning: value of vascular laboratory accreditation.

OBJECTIVES: The purpose of this study was to evaluate the reliability of carotid duplex ultrasound scanning performed by nonaccredited vascular laboratories and to assess the clinical effect on patient management. METHODS: We retrospectively reviewed concordance of findings of carotid duplex ultrasound scanning between laboratories accredited by the Intersocietal Commission for Accreditation of Vascular Laboratories and nonaccredited laboratories in 174 patients with asymptomatic disease referred to tertiary care community hospitals for surgical evaluation for carotid endarterectomy (CEA) between January 2001 and December 2002, and evaluated changes in clinical management made on the basis of repeat examinations. RESULTS: Concordant findings were noted in 171 of 348 arteries (49%), predominantly those with minimal or mild disease (114 arteries; 67%). Discordant findings of no clinical significance were found in 54 arteries (16%). Clinically significant discordant findings were noted in 123 arteries (35%) in 107 patients (61%). In 104 arteries (88 patients) stenosis was overestimated by the nonaccredited laboratory secondary to technical error (19 arteries), use of B-mode imaging data alone (36 arteries), and use of inappropriate velocity criteria (49 arteries). None of these patients underwent CEA. Stenosis was significantly underestimated in 19 arteries (19 patients); all of these patients underwent uncomplicated CEA. CONCLUSIONS: Incorrect physician interpretation of data is the most common cause of error in carotid duplex ultrasound scanning performed in nonaccredited vascular laboratories. Results of carotid duplex ultrasound scanning from nonaccredited laboratories should be considered with extreme caution, and do not appear reliable in planning treatment of obstructive disease.

Complications of preinjury warfarin use in the trauma patient.

BACKGROUND: The frequency of use of warfarin anticoagulation increases significantly in the elderly population. It remains controversial whether this puts these patients at increased risk for hemorrhagic complications after trauma. METHODS: We prospectively evaluated consecutive trauma patients who were taking warfarin and compared their outcomes to a group of age-matched patients with head injuries but not taking warfarin. RESULTS: One hundred fifty-nine trauma patients on warfarin were evaluated, 94 (59%) with some type of head trauma; 25 of these 94 patients (27%) had documented intracranial trauma. Fifteen patients died (9.4%); they had an international normalized ratio of 3.3 +/- 1.6 versus 3.0 +/- 2.1 for survivors in the warfarin group (p = 0.585). Twelve deaths were in the group of 25 patients with intracranial injuries (48%). Three patients without head injury died (5%) of other causes not related to warfarin or hemorrhage at a mean of 13 days after admission. Ten of 12 patients on warfarin with intracranial injuries who died had documented loss of consciousness (LOC); two patients who died secondary to an isolated intracranial injury had no LOC. Of 70 age-matched patients with head trauma not taking warfarin, 47 (67%) had intracranial injury and 5 of these died (10%) (p < 0.001 for both values compared with study patients). There were no significant differences for patients with intracranial injury comparing those on warfarin and those who were not in terms of age, gender, mechanism of injury, Injury Severity Score, or Glasgow Come Scale score. CONCLUSION: We conclude that the preinjury use of warfarin does not place the trauma patient at increased risk for fatal hemorrhagic complications in the absence of head trauma. Furthermore, the presence of a head trauma alone is not predictive of mortality. However, the presence of intracranial injury is strongly associated with a mortality rate that is significantly higher than patients with head trauma who are not taking warfarin. LOC is also associated with mortality, but the absence of loss of consciousness does not reliably indicate the absence of intracranial injury or risk of death.

Duplex ultrasound imaging with an ultrasound contrast agent: the economic alternative to CT angiography for aortic stent graft surveillance.

The use of endovascular stent graft repair for aortic aneurysmal disease has become increasingly common, with the added requirement for close postoperative surveillance to detect the presence of endoleaks or graft migration. The most commonly used technique for surveillance is computed tomography (CT) angiography, with the need for intravenous contrast posing 1 limitation in those patients with renal dysfunction and the cost of this testing presenting an economic limitation. Early results of duplex imaging in the authors' Vascular Laboratory using an intravenous ultrasound contrast agent have shown sensitivity and specificity equivalent to those of CT angiography, with no evidence of any related morbidity. They have evaluated the cost effectiveness of using duplex ultrasound imaging as the primary surveillance technique for postoperative follow-up in aortic stent graft patients. Surveillance protocols now require that 8 follow-up examinations be performed in the first 3 years after stent graft placement. The charges for CT angiography in their institution average 2,779 dollars per study, for a 3-year total of 22,232 dollars per patient. The charges for aortic duplex ultrasound average 525 dollars per study, with a 3-year total of 4,200 dollars per patient. Adding the cost of routine abdominal radiographs to confirm stent graft position (147 dollars per study) would bring this 3-year total to 5,376 dollars, a savings of 16,856 dollars per patient. For every 100 patients who are followed up after stent graft placement, this represents a 3-year savings of more than 1.6M dollars. Promising early results of duplex ultrasound imaging with an intravenous contrast agent show sensitivity and specificity equivalent to those of CT angiography in detecting aneurysm size and graft endoleaks or other hemodynamic abnormalities. If these results can be demonstrated in larger patient series, this technique should become the method of choice for stent graft surveillance, for it offers very significant economic advantages and avoids the complications of intravenous contrast-induced renal dysfunction.