Paul W. White

Effect of chronic renal insufficiency on outcomes of carotid endarterectomy

OBJECTIVE Conflicting data exist regarding the effect of chronic renal insufficiency (CRI) on carotid endarterectomy (CEA) outcomes. A large database was used to analyze the effect of CRI, defined by glomerular filtration rate (GFR), as an independent risk factor of CEA. METHODS Prospectively collected data regarding CEAs performed at 123 Veterans Affairs Medical Centers as part of the National Surgical Quality Improvement Program were retrospectively analyzed. Renal function was used to divide patients into three CRI groups: normal or mild (control; GFR >/=60 mL/min/1.73 m(2)), moderate (GFR 30 to 59), and severe (GFR <30). Bivariate analysis and multivariate logistic regression were used to characterize risk factors and their associations with 30-day morbidity and mortality. RESULTS Between Jan 1, 1996, and Dec 31, 2003, 22,080 patients underwent CEA. Patients missing creatinine levels, already dialysis-dependent, or in acute renal failure just before surgery were excluded. This left 20,899 available for analysis, of which 13,965 had a GFR of >/=60, 6,423 had a GFR of 30 to 59, and 511 had a GFR of <30. The incidence of neurologic complications did not differ significantly (control, 1.7%; moderate CRI, 1.9%; severe CRI, 2.7%). The moderate CRI group experienced significantly more cardiac events (1.7% vs 0.9% for controls, P < .001). This remained predictive in the multivariate model even adjusting for all other risk factors (adjusted odds ratio [AOR], 1.6; 95% confidence interval [CI], 1.1-2.3; P = .009). The moderate CRI group also had higher rates of pulmonary complications (2.1% vs 1.3% control; P < .001; AOR, 1.3; 95% CI, 1.0-1.7; P = .031) but not 30-day mortality (P = .269). Those with severe CRI had a much higher mortality (3.1% vs 1.0% control, P < .001), which remained significant in the multivariate model (AOR, 2.7; 95% CI, 1.6-4.8; P < .001). CONCLUSION Although impaired renal function does not independently increase the risk of neurologic or infectious complications, CRI is a significant negative independent risk factor in predicting other outcomes after CEA. Patients with moderate CRI (GFR, 30-59 mL/min/1.73 m(2)) are at increased risk for cardiac and pulmonary morbidity, but not death, and those with severe CRI (GFR <30 mL/min/1.73 m(2)) have a much higher operative mortality. Patients with CRI should be carefully evaluated before CEA to optimize existing cardiac and pulmonary disease. Understanding this increased risk may assist the surgeon in preoperative counseling and perioperative management.

The use of retrievable inferior vena cava filters in severely injured military trauma patients.

OBJECTIVE Important recent data on retrievable inferior vena cava filter (R-IVCF) used in civilian trauma centers suffer from poor follow-up in these transient patients. Because US military casualties can be more easily followed globally, our objective was to further characterize R-IVCF outcomes in a trauma population with improved follow-up. METHODS From July 2003 to June 2007, trauma registry records were retrospectively reviewed for US soldiers injured in Iraq and Afghanistan who had R-IVCF placement. Indications, type of filter, complications, outcomes, and retrieval data were analyzed. RESULTS Seventy-two R-IVCFs were placed during the study period. Mean follow-up was 28.0 +/- 12.0 months, in 61 (85%) patients. Mean injury severity score (ISS) was 36.3 +/- 10.4 and mean patient age was 27.4 +/- 6.4 years. Fifty-nine R-IVCFs (82%) were not retrieved due to: death (1, 1.3%), technical failure (2, 2.8%), lost to follow-up (11, 15.2%), or contraindications to retrieval (45, 62.5%). Thirteen R-IVCFs were successfully removed, an overall retrieval rate of 18%. Median dwell time of those removed was 47 days (range, 10-94). IVCF indications were prophylactic in 23 (32%) and therapeutic in 49 (68%) cases. Both retrieval failures were due to incorporation into the caval wall, attempted at 90 and 156 days. Deep vein thromboses at the insertion site or pulmonary embolism following R-IVCF placement or removal were not observed. To date, there have been no reports of IVC stenosis or occlusion. CONCLUSION R-IVCFs were safely and effectively used in severely injured military trauma patients with high ISS. Despite improved follow-up, overall retrieval remained low, reflecting the civilian experience. Indication, rather than follow-up losses, accounted for the low retrieval rate. Practice patterns for R-IVCF in trauma may need to be re-examined to optimize outcomes.

Sixty-four Slice Multidetector Computed Tomographic Angiography in the Evaluation of Vascular Trauma

BACKGROUND Artifacts produced by metallic fragments and orthopedic hardware limit the usefulness of conventional computed tomography in many military trauma patients. Contemporary literature suggests that multidetector computed tomographic angiography (MDCTA) by resolving these limitations may provide a useful noninvasive alternative to invasive arteriography. The objective of this study is to review the utility of MDCTA in the evaluation of recent combat casualties with vascular injuries. METHODS Data on all vascular trauma patients seen by our service has been collected prospectively and entered into a database. A retrospective review was conducted of patients seen from August through December 2006 who underwent MDCTA. Patient demographics, mechanism of injury, modality of evaluation, and findings were recorded. RESULTS Twenty patients underwent MDCTA. Thirteen patients were injured by blast fragments. Seven patients were injured by gunshot wounds. Nineteen of 20 studies were diagnostic and one was judged to be indeterminate. Studies in nine patients identified arterial injuries. Multiple extremities were evaluated with a single study in 16 patients. Fifteen studies assessed the lower extremities, four the upper extremities and two the neck. Fourteen patients in this series had retained fragments, 10 had external fixators or intramedullary rods, and only 4 had neither retained fragments nor orthopedic hardware. MDCTA allowed for assessment of the arterial runoff despite hardware or fragments in 15 of 16 (94%) patients. Comparative studies were available in four patients in addition to MDCTA. There were no missed injuries in these four patients. CONCLUSIONS MDCTA yielded high resolution images that were very useful for the delayed evaluation of combat casualties. The presence of metallic fragments or orthopedic hardware did not significantly interfere with MDCTA. It is a reliable and promising alternative to traditional arteriography for evaluating clinically occult vascular trauma.

Intravascular Ultrasound—Guided Inferior Vena Cava Filter Placement in the Military Multitrauma Patients: A Single-Center Experience

Background: High velocity fragments have resulted in a multitude of complex injuries in the military patients, placing them at increased risk of venous thromboembolism. Methods: A retrospective analysis was performed of all the intravascular ultrasound (IVUS)-guided bedside inferior vena cava (IVC) filters placed between August 2003 and October 2007. Results: Fourteen patients had bedside IVUS-guided retrievable filter placement. Thirteen males and one female and the mean (+SD) injury severity scores (ISS) was 37.2 (+9.9). The most common causes of injury were explosive devices (57%), gunshot wounds (28%), rocket-propelled grenades (7%), and motor vehicle crashes (7%). Indications for filter insertion were deep venous thrombosis in 36% of patients and pulmonary embolus in 28%. Thirty five percent had filters inserted prophylactically. Conclusions: Military trauma population ISS is considerably higher than what is reported in the civilian population. The bedside IVUS-guided IVC filter insertion is particularly useful in this population.

Contemporary management of combat-related vertebral artery injuries.

BACKGROUND Vertebral artery injuries (VAIs) following cervical trauma are uncommon. Advances in imaging technology and emerging endovascular therapies have allowed for the improved diagnosis and treatment of VAIs. We aimed to examine the contemporary management of combat-related penetrating VAIs during current US military operations. METHODS A retrospective review was performed on US casualties with combat-related VAIs evacuated to a single military institution in the US from September 2001 to 2010 for definitive management. Casualty demographics, mechanism of injury, location and type of VAI, neurologic sequela, associated injuries, method of diagnosis, and therapeutic management were collected. RESULTS Eleven casualties with a mean age of 26 years (mean [SD] ISS, 18 [7.0]) were found to have VAIs from gunshot wounds (6, 55%) or blast fragments (5, 45%). Cervical spine fractures (8, 72%), facial fractures (5, 45%), and spinal cord injury (3, 27%) were not uncommon. One casualty experienced a posterior cerebellar and parietal infarcts. All injuries were evaluated with digital subtraction angiography, 64-slice multidetector row computed tomography, or both. Casualties were noted to have vertebral artery occlusion (4, 36%), pseudoaneurysms (5, 45%), dissection (1, 9%), or arteriovenous fistula (1, 9%), with most injuries occurring in the V2 segment (6, 55%). Pseudoaneurysms were treated with coiling or stent-assisted coiling. Of 11 casualties, 6 were managed nonoperatively, half of whom with anticoagulation or antiplatelet therapy. CONCLUSION VAIs are infrequent in modern combat operations, occurring in only 3% of casualties experiencing arterial injuries and are often incidentally discovered during the delayed secondary evaluation of penetrating face and neck injuries at higher echelons of care. One should have a high index of suspicious for a VAI in a casualty with concurrent cervical spine fractures. Endovascular therapies using coils and covered stents have expanded the management options and simplified the treatment of combat-related VAIs. LEVEL OF EVIDENCE Therapeutic study, level V.