Girma Tefera

Complications of spinal fluid drainage in thoracoabdominal aortic aneurysm repair: A report of 486 patients treated from 1987 to 2008

OBJECTIVE Spinal fluid drainage reduces paraplegia risk in thoracic (TAA) and thoracoabdominal (TAAA) aortic aneurysm repair. There has not been a comprehensive study of the risks of spinal fluid drainage and how these risks can be reduced. Here we report complications of spinal fluid drainage in patients undergoing TAA/TAAA repair. METHODS The study comprised 648 patients who had TAA or TAAA repair from 1987 to 2008. Spinal drains were used in 486 patients. Spinal fluid pressure was measured continuously, except when draining fluid, and was reduced to <6 mm Hg during thoracic aortic occlusion and reperfusion. After surgery, spinal fluid pressure was kept <10 mm Hg until patients were awake with normal leg lift. Drains were removed 48 hours after surgery. Spinal and head computed tomography (CT) scans were performed in patients with bloody spinal fluid or neurologic deficit. We studied the incidence of headache treated with epidural blood patch, infection, bloody spinal fluid, intracranial and spinal bleeding on CT, as well as the clinical consequences. RESULTS Twenty-four patients (5%) had bloody spinal fluid. CT exams showed seven had no evidence of intracranial hemorrhage, 14 (2.9%) had intracranial blood without neurologic deficit, and three with intracranial bleeding and cerebral atrophy had neurologic deficits (1 died, 1 had permanent hemiparesis, and 1 with transient ataxia recovered fully). Two patients without bloody spinal fluid or neurologic deficit after surgery presented with neurologic deficits 5 days postoperatively and died from acute on chronic subdural hematoma. Neurologic deficits occurred after spinal fluid drainage in 5 of 482 patients (1%), and 3 died. The mortality from spinal fluid drainage complications was 0.6% (3 of 482). By univariate and multivariate analysis, larger volume of spinal fluid drainage (mean, 178 mL vs 124 mL, P < .0001) and higher central venous pressure before thoracic aortic occlusion (mean, 16 mm Hg vs 13 mm Hg, P < .0012) correlated with bloody spinal fluid. CONCLUSION Strategies that reduce the volume of spinal fluid drainage but still control spinal fluid pressure are helpful in reducing serious complications. Patients with cerebral atrophy are at increased risk for complications of spinal fluid drainage.

A quantitative assessment of the impact of intercostal artery reimplantation on paralysis risk in thoracoabdominal aortic aneurysm repair.

Objectives:We previously demonstrated an 80% reduction in paraplegia risk using hypothermia, naloxone, steroids, spinal fluid drainage, intercostal ligation, and optimizing hemodynamic parameters. This report demonstrates that intercostal revascularization for the last 3 years further reduced our paraplegia risk index by 75%. Methods:We evaluated 655 patients who had thoracic or thoracoabdominal aneurysm repair for factors that affected paraplegia risk including aneurysm extent, acuity, cardiac function, blood pressure mean arterial pressure, and spinal fluid drainage with naloxone (SFDN). Eighteen patients died during or shortly after surgery leaving 637 patients for analysis of paralysis. We evaluated the effect of intercostal reimplantation (IRP) using a highly accurate (r2 > 0.88) paraplegia risk index we developed and published previously. Results:Fifty-eight percent of patients were male with a mean age of 67. Thirty-three percent were acute with rupture, acute dissection, mycotic aortitis, and trauma. Eighty (12%) had dissections. Thirty-five patients had paraplegia or paraparesis (5.4%). Significant factors by univariate analysis (P < 0.05) were Crawford type 2, acuity, SFDN, cardiac index after unclamping, mean arterial pressure during crossclamping, and IRP. In multivariate modeling, aneurysm extent, SFDN, acuity, and IRP remained significant (P < 0.02). The paraplegia risk index declined from 0.20 to 0.05 (P < 0.03). Conclusions:The incidence of paralysis after TAAA repair decreased from 4.83% to 0.88% and paralysis risk index decreased from 0.26 to 0.05 when intercostal artery reimplantation was added to neuroprotective strategies that had already substantially reduced paralysis risk. These findings suggest that factors that affect collateral blood flow and metabolism account for approximately 80% of paraplegia risk and intercostal blood flow accounts for 20% of risk. This suggests a limit to paraplegia risk reduction in thoracoabdominal endograft patients. Early results in this emerging field support this prediction of high paraplegia risk with thoracoabdominal branched endografts with extensive aortic coverage.

Endovascular Abdominal Aortic Aneurysm Repair: Nonenhanced Volumetric CT for Follow-up

PURPOSE To evaluate the clinical usefulness of volumetric analysis at nonenhanced computed tomography (CT) as the sole method with which to follow up endovascular abdominal aortic aneurysm repair (EVAR) and to identify endoleaks causing more than 2% volumetric increase from the previous volume determination. MATERIALS AND METHODS The study had institutional review board approval. Images were reviewed retrospectively in a HIPAA-compliant manner for 230 CT studies in 70 patients (11 women, 59 men; mean age, 74 years) who underwent EVAR. The scannning protocol consisted of three steps: (a) contrast material-enhanced CT angiography before endovascular stent placement, (b) contrast-enhanced CT angiography 0-3 months after repair to depict immediate complications, and (c) nonenhanced CT at 3, 6, and 12 months after repair. At each follow-up visit, immediate aortic volume analysis was performed. If the interval volumetric change was 2% or less, no further imaging was performed. If the volume increased by more than 2% on the nonenhanced CT image, contrast-enhanced CT angiography was performed immediately to identify the suspected endoleak. Confidence intervals (CIs) were obtained by using bootstrapping to account for repeated measurements in the same patients. RESULTS Mean volume decrease was -3.2% (95% CI: -4.7%, -1.9%) in intervals without occurrence of a clinically relevant endoleak (n = 183). Types I and III high-pressure endoleaks (n = 10) showed a 10.0% (95% CI: 5.0%, 18.2%) interval volumetric increase. Type II low-pressure endoleaks (n = 37) showed a 5.4% (95% CI: 4.6%, 6.2%) interval volumetric increase. Endoleaks associated with minimal aortic volume increase of less than 2% did not require any intervention. This protocol reduced radiation exposure by approximately 57%-82% in an average-sized patient. CONCLUSION Serial volumetric analysis of aortic aneurysm with nonenhanced CT serves as an adequate screening test for endoleak, causing volumetric increase of more than 2% from the volume seen at the previous examination.

Effect of early plasma transfusion on mortality in patients with ruptured abdominal aortic aneurysm

BACKGROUND The ratio of red blood cell (PRBC) transfusion to plasma (FFP) transfusion (PRBC:FFP ratio) has been shown to impact survival in trauma patients with massive hemorrhage. The purpose of this study was to determine the effect of the PRBC:FFP ratio on mortality for patients with massive hemorrhage after ruptured abdominal aortic aneurysm (RAAA). METHODS A retrospective review was performed of patients undergoing emergent open RAAA repair from January 1987 to December 2007. Patients with massive hemorrhage (≥10 units of blood products transfused prior to conclusion of the operation) were included. The effects of patient demographics, admission vital signs, laboratory values, peri-operative variables, amount of blood products transfused, and the PRBC:FFP ratio on 30-day mortality were analyzed by multivariate analysis. RESULTS One hundred and twenty-eight of the 168 (76%) patients undergoing repair for RAAA received at least 10 units of blood products within the peri-operative period. Mean age was 73.1 ± 9.1 years, and 109 (85%) were men. Thirty-day mortality was 22.6% (29/128), including 11 intra-operative deaths. By multivariate analysis, 30-day mortality was markedly lower (15% vs 39%; P < .03) for patients transfused at a PRBC:FFP ratio ≤2:1 (HIGH FFP group) compared with those transfused at a ratio of >2:1 (LOW FFP), and the likelihood of death was more than 4-fold greater in the LOW FFP group (odds ratio 4.23; 95% confidence interval, 1.2-14.49). Patients in the HIGH FFP group had a significantly lower incidence of colon ischemia than those in the LOW FFP group (22.4% vs 41.1%; P = .004). CONCLUSION For RAAA patients requiring massive transfusion, more equivalent transfusion of PRBC to FFP (HIGH FFP) was independently associated with lower 30-day mortality. The lower incidence of colonic ischemia in the HIGH FFP group may suggest an additional benefit of early plasma transfusion that could translate into further mortality reduction. Analysis from this study suggests the potential feasibility for a more standardized protocol of initial resuscitation for these patients, and prospective studies are warranted to determine the optimum PRBC:FFP ratio in RAAA patients.

Outcomes after endarterectomy for chronic mesenteric ischemia

OBJECTIVES A retrospective study was performed to identify optimal factors affecting outcomes after open revascularization for chronic mesenteric ischemia. METHODS All patients who underwent open surgery for chronic mesenteric ischemia from 1987 to 2006 were reviewed. Patients with acute mesenteric ischemia or median arcuate ligament syndrome were excluded. Mortality, recurrent stenosis, and symptomatic recurrence were analyzed using logistic regression, and univariate and multivariate analysis. RESULTS We identified 80 patients (69% women, 31% men). Mean age was 64 years (range, 31-86 years). Acute-on-chronic symptoms were present in 26%. Presenting symptoms included postprandial pain (91%), weight loss (69%), and food fear and diarrhea (25%). Preoperative imaging demonstrated severe (>70%) stenosis of the superior mesenteric artery in 75 patients (24 occluded), the celiac axis in 63 (20 occluded), and the inferior mesenteric artery in 53 (20 occluded). Multivessel disease was present in 72 patients (90%), and 40 (50%) underwent multivessel reconstruction. Revascularization was achieved by endarterectomy in 37 patients, mesenteric bypass in 29, and combined procedures in 14. Concurrent aortic reconstruction was required in 13 patients (16%). Three hospital deaths occurred (3.8%). Mean follow-up was 3.8 years (range, 0-17.2 years). One- and 5-year survival was 92.2% and 64.5%. Mortality was associated with age (P = .019) and renal insufficiency (P = .007), but not by clinical presentation. Symptom-free survival was 89.7% and 82.1% at 1 and 5 years, respectively. Symptoms requiring reintervention occurred in nine patients (11%) at a mean of 29 months (range, 5-127 months). Multivariate analysis showed that freedom from recurrent symptoms correlated with endarterectomy for revascularization (5.2% vs 27.6%; hazard ratio, 0.20; 95% confidence interval, 0.04-0.92; P = .02). CONCLUSION For open surgical candidates, endarterectomy appears to provide the most durable long-term symptom relief in patients with chronic mesenteric ischemia.

The effect of warfarin therapy on endoleak development after endovascular aneurysm repair (EVAR) of the abdominal aorta

OBJECTIVES The presence of an endoleak after endovascular abdominal aortic aneurysm (AAA) repair (EVAR) may predispose to sac expansion and potential sac rupture. The incidence of endoleak after AAA repair can be as high as 20% to 30%. We investigated whether warfarin anticoagulation was an independent risk factor for endoleak after EVAR for AAA. METHODS All AAA patients who underwent elective EVAR were prospectively followed-up. Data for demographics, clinical comorbidities, outcomes, EVAR devices, and anticoagulation methods were recorded. All patients underwent routine follow-up at 1, 6, and 12 months and annually thereafter. Computed tomography angiography (CTA) with 3-dimensional (3D) volumetric analysis was also completed. RESULTS During a 7-year period, 127 consecutive patients with infrarenal AAAs who underwent EVAR were monitored for a mean of 2.14 years. The average age at the time of EVAR was 73.8 years. Warfarin therapy alone was administered to 24 patients, and anticoagulation with antiplatelet therapy alone was administered to 103. During the study period, 38 (29.9%) endoleaks were documented. The overall endoleak rate was 13 of 24 in the warfarin group and 25 of 103 in the antiplatelet group (P = .004). CTA 3D volumetric aneurysm sac analysis showed an increase of 16.09% in the warfarin study group and a reduction of 9.71% in the antiplatelet group (P = .04). CONCLUSIONS Anticoagulation with warfarin appears to be linked to an increased risk for the development of endoleak after EVAR, specifically type II. Volumetric analysis showed warfarin therapy also contributed to persistent aneurysm sac expansion. These data suggest that patients who require warfarin anticoagulation for other indications should be advised that they might be at an increased risk for the development of endoleaks, subsequent secondary interventions, persistent sac expansion, and possible delayed sac rupture.

Blunt thoracic aortic injury: open or stent graft repair?

BACKGROUND Despite a lack of level I evidence, endovascular stent grafting is frequently used for the treatment of blunt thoracic aortic injury. The purpose of this study is to compare the outcomes between open and endovascular repair of traumatic rupture of the thoracic aorta. METHODS This article is based on a single-institution review of all consecutive patients treated for blunt aortic injury at the University of Wisconsin Hospital and Clinics between October 1999 and May 2007. This study was reviewed and approved by the institutional review board. Patients were identified from our Level 1 trauma registry. Inclusion criteria for this study was based on computed tomographic or angiographic evidence of thoracic aortic injury distal to the left subclavian artery. Two groups were identified: patients who underwent open repair (OR) and, patients who underwent endovascular repair (ER). Patient demographics, mechanism of injury, Injury Severity Score, associated injuries, comorbid conditions, intraoperative findings, postoperative complications, and duration of hospital stay were analyzed. Data regarding these patients and their injuries were retrieved from our trauma registry as well as chart review and outpatient records. The outcomes from OR and ER were compared using the Fisher exact test. P values less than 0.05 were considered statistically significant. RESULTS During the 8-year period, 26 consecutive patients were treated for blunt aortic injury (OR = 12 and ER = 14). There were 20 men, and the mean age was 36 years. There were no differences between the groups in the mechanism of injury, Injury Severity Score, or number of associated injuries on initial presentation. On an intent-to-treat basis, the endovascular therapy was technically successful 100% of the time. There was no procedure-related mortality. There was 1 patient, however, in the OR group with presumed recurrent laryngeal nerve palsy. There was no incident of treatment-related paraplegia in either group. The 1-year survival for OR and ER patients was 93% and 92%, respectively. At 1 year, 25% of patients in the OR group and 18% of patients in the ER group required reinterventions. Mean operating room time was 309 minutes for the ERs and 383 minutes for the patients who underwent OR. Intraoperative blood product administration was greater in the OR group (P = .055); there was no difference between the groups, however, in the total blood products administered for a given hospital stay. The mean duration of hospital stay was 13 days for the OR group and 13.9 days for the ER group. CONCLUSION There were no significant differences with respect to morbidity or mortality between these 2 groups. These data suggest that ER is at least as safe as OR for blunt aortic injury.

Syndromes Associated With the Deep Veins: Phlegmasia Cerulea Dolens, May-Thurner Syndrome, and Nutcracker Syndrome

Although phlegmasia cerulea dolens, May-Thurner syndrome, and nutcracker syndrome are rare entities, knowledge of these syndromes associated with the deep veins is essential. This study presents current management of these disorders, including diagnostic and interventional strategies. Endovascular techniques have evolved and now play a significant role in the treatment of both phlegmasia cerulea dolens and May-Thurner syndrome. However, endovascular therapy for nutcracker syndrome remains untested.

Absence of buttock claudication following stent-graft coverage of the hypogastric artery without coil embolization in endovascular aneurysm repair.

Purpose: To evaluate the safety and efficacy of stent-graft coverage of the hypogastric artery origin without coil embolization during endovascular treatment of aortoiliac or iliac aneurysms. Methods: A retrospective study was conducted of patients who underwent endovascular aneurysm repair with endograft coverage of the hypogastric artery between September 2001 and September 2005. Among the 88 patients who underwent EVAR during the study period, 21 patients (19 men; mean age 77±6 years, range 67–86) had unilateral hypogastric artery coverage without coil embolization. Aneurysmal arteries included 11 aortoiliac, 8 isolated common iliac arteries (CIA), and 2 isolated hypogastric arteries. Preoperative AAA size was a mean 57 mm (range 46–73), and mean CIA aneurysm diameter was 36 mm (range 17–50). All covered hypogastric arteries were patent prior to the procedure. The stent-grafts implanted were 10 Excluder, 10 AneuRx, and 1 Zenith. Clinical outcome focused on mortality and morbidity, including the occurrence and duration of new-onset buttock claudication, which was further correlated with superior gluteal and profunda femoris artery patency. Results: Immediate seal was achieved in all patients. Mean follow-up was 16 months (range 1–54). No type I endoleaks developed from the aortic or external iliac artery, and no type II endoleaks were found from the origin of the hypogastric artery. New-onset buttock claudication occurred in 2 (9.5%) patients, but resolved in both within 4 months. No additional secondary procedures, aneurysm rupture, or aneurysm-related death occurred. Conclusion: Stent-graft coverage of the orifice of the hypogastric artery without coil embolization is a safe and effective adjunct during the treatment of aortoiliac or iliac aneurysm, with a low incidence of buttock claudication.

Creating Change Through Collaboration: A Twinning Partnership to Strengthen Emergency Medicine at Addis Ababa University/Tikur Anbessa Specialized Hospital—A Model for International Medical Education Partnerships

BACKGROUND Morbidity and mortality due to the lack of an organized emergency medical care system are currently high in Ethiopia. Doctors, nurses, and other medical staff often have limited or no formal training on how to handle emergencies. Because of insufficient human and resource capacity needed to assess and treat acutely ill patients, many who are injured may die unnecessarily, at the site of injury, during transport, or at the hospital. OBJECTIVES This article describes the development of a twinning partnership between Addis Ababa University (AAU), the University of Wisconsin-Madison (UW), and the nonprofit organization People to People (P2P), to strengthen emergency care at Tikur Anbessa Specialized Hospital (TASH) and increase the number of trained emergency medical professionals. METHODS The partnership applied the six-phase twinning partnership model, with the overall goal of enhancing and strengthening emergency and trauma care by building institutional and human resource capacity. This was achieved by 1) developing local leaders in emergency medicine (EM), 2) creating training modules adapted to the Ethiopian context, 3) launching an emergency training center, and 4) supporting academic program development. The authors evaluated the programs effectiveness based on our achievements toward these goals. RESULTS Results include: 1) eight Ethiopian faculty completed a condensed EM fellowship in the United States. Now six Ethiopian physicians serve as EM faculty and two as pediatric EM faculty. 2) Nine emergency training modules were adapted to the Ethiopian context. 3) An emergency training center was opened in 2010 and to date has trained over 4,000 Ethiopian medical professionals. 4) Two academic training programs (EM residency and masters nursing programs) were initiated. CONCLUSIONS With many complex factors affecting the burden of emergency care, innovative and interdisciplinary collaborations are needed in Ethiopia to train medical workers, build local leadership capacity, strengthen infrastructure, and inform policies. The short-term achievements of this twinning model could suggest that long-term, institution-to-institution collaborations that are driven by local stakeholders are an effective strategy to create equitable relationships and build sustainable health systems and may serve as a model for other global health partnerships.