Jeremy R. Harris

Technical factors are strongest predictors of postoperative renal dysfunction after open transperitoneal juxtarenal abdominal aortic aneurysm repair.

OBJECTIVE Juxtarenal abdominal aortic aneurysms (AAAs) have predominantly been repaired using an open technique. We present a series of patients with juxtarenal AAAs and analyze multiple factors predictive of postoperative renal dysfunction. METHODS Between March 2000 and September 2011, all patients in our prospectively maintained database undergoing juxtarenal AAA repair were evaluated for demographics, operative details, and in-hospital outcomes. Postoperative renal dysfunction was classified using the RIFLE (risk, injury, failure, loss, end-stage renal disease) criteria (glomerular filtration rate decrease >25%). The relationship between perioperative factors and postoperative renal dysfunction was explored using both univariate and multivariate analysis (logistic regression). RESULTS Of 169 patients, 76 (45%) required clamping above one renal artery, whereas 93 patients (55%) required clamping above both renal arteries. Mean (standard deviation) renal ischemia time was 29.2 (8.9) minutes (range, 12-65 minutes). Twenty-seven patients (16%) underwent adjunctive renal procedures, 19 (11.3%) required left renal vein division, and 130 (76.9%) received intraoperative mannitol. Postoperative renal dysfunction occurred in 63 patients (37.3%), with the majority (69%) resolving during hospital stay. Seven patients (4.1%) required postoperative dialysis, which was permanent in two cases. Patients who developed postoperative renal dysfunction had significantly longer mean renal ischemia times (34.7 [9.3] minutes vs 25.9 [6.6] minutes; P < .001), a higher rate of bilateral suprarenal aortic clamping (68.3% vs 47.2%; P = .008), higher rates of adjunctive renal artery procedures (26.7% vs 8.8%; P = .002), and higher rates of left renal vein division (20.6% vs 5.7%; P = .003). Logistic regression identified left renal vein division, renal ischemia time, and aortic clamp position as the strongest predictors of renal dysfunction. The use of mannitol was seen to be protective. Overall in-hospital mortality was 4.1% and was 9.5% among patients with postoperative renal dysfunction. CONCLUSIONS Postoperative transient renal dysfunction occurred in 37.3% of patients after open juxtarenal AAA repair, with a low incidence of dialysis and a low rate of permanent dysfunction. Technical factors including renal ischemia time, aortic clamp position, and left renal vein division are the strongest predictors of renal dysfunction. The use of intraoperative mannitol was associated with decreased postoperative renal dysfunction.

Aortic dilatation after endovascular repair of blunt traumatic thoracic aortic injuries

OBJECTIVE Endovascular repair of blunt traumatic thoracic aortic injuries (BTAI) has become routine at many trauma centers despite concerns regarding durability and aortic dilatation in these predominantly young patients. These concerns prompted this examination of thoracic aortic expansion after endovascular repair of a BTAI. METHODS The immediate postoperative and most recent computed tomography (CT) scans of patients who had undergone urgent endovascular repair of a BTAI and had at least 1 year of follow-up were reviewed. Diameter measurements were made at four predetermined sites: immediately proximal to the left subclavian artery (D1), immediately distal to the left subclavian artery (D2), distal extent of the endograft (D3), and 15 mm beyond the distal end of the endograft (D4). Split screens permitted direct comparison of measurements between CTs at the corresponding levels. RESULTS During a 6-year period (2001-2007), 21 patients (mean age, 42.9 years; range, 19-81 years) underwent endovascular repair of a BTAI, 17 with at least 1 year of follow-up (mean, 2.6 years; range, 1-5.5 years). No patients required reintervention during this period. The mean rate of dilatation for each level of the thoracic aorta in mm/year was: D1, 0.74 (95% confidence interval [CI], 0.42-1.06); D2, 0.83 (95% CI, 0.55-1.11); D3, 0.63 (95% CI, 0.37-0.89); D4, 0.47 (95% CI, 0.27-0.67). The rate of expansion of D2 differed significantly vs D4 (P = .025). CONCLUSIONS During the first several years of follow-up, the proximal thoracic aorta dilates minimally after endovascular repair of BTAIs, with the segment just distal to the left subclavian artery expanding at a slightly greater rate. Longer-term follow-up is necessary to determine whether this expansion continues and becomes clinically significant.

Trends in management of abdominal aortic aneurysms

OBJECTIVE The purpose of this study was to evaluate patients undergoing elective repair of infrarenal abdominal aortic aneurysms (AAAs) and the longitudinal trends in surgical management (open repair vs endovascular aneurysm repair [EVAR]), factors associated with the choice of surgical technique, and differences in the rate of in-hospital mortality at a single large-volume Canadian center. METHODS This retrospective cohort study used data from a prospectively collected vascular surgery database and reviewed all patients undergoing elective repair of an infrarenal AAA over a recent 10-year period (June 2000-May 2010). Information was reviewed regarding surgical techniques, patient demographics, and short-term outcomes. Subsequent analysis included univariate statistics and multivariable logistic regression with data presented as odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS A total of 1942 patients underwent elective AAA repair over this 10-year study period, 1067 (54.9%) via open repair and 875 (45.1%) via EVAR. The proportion of patients undergoing EVAR was significantly higher in the latter half of the study period compared to the first half (55.8% vs 33.9%; P < .01). Older patients (75 vs 71; P < .01) and those with higher American Society of Anesthesiologists classifications (P < .01) were more likely to receive endovascular repair than open repair. The overall in-hospital mortality rate in the entire cohort was low (2.3% for EVAR and 3.9% for open repair), and after multivariable logistic regression and adjustment for preoperative factors, in-hospital mortality was significantly higher in patients with open AAA repair (OR, 1.8; 95% CI, 1.04-3.13; P = .04). CONCLUSIONS This 10-year analysis shows a significant shift toward an endovascular approach in the repair of infrarenal AAAs at our Canadian center. Similar to other jurisdictions, higher risk and older patients are more likely to be treated with an endovascular repair resulting in a survival advantage in these patients compared to standard open repair.

Early Mortality Following Endovascular Versus Open Repair of Ruptured Abdominal Aortic Aneurysms

Purpose: To determine whether endovascular repair (EVAR) offers a survival advantage over open repair (OAR) with ruptured abdominal aortic aneurysms (RAAA). Methods: Retrospective analysis of RAAA patients treated between 2003 and 2008. Univariate and multivariate analyses were performed. Results: 167 patients presented with RAAA (OAR = 135, 80.8%, EVAR = 32, 19.2%). On univariate analysis, EVAR was associated with a decreased mortality relative to OAR, (15.6% vs 43.7%, P = .004). Patients who survived were younger (P < .0005), had a higher blood pressure (P < .0005), level of consciousness (P < .0005), and hemoglobin (P = .018), and a lower urea (P = .005) and international normalized ratio (INR; P = .001). On multivariate analysis, type of repair remained an independent predictor of 30-day mortality (OR: 0.121; 95% CI: 0.021-0.682, P = .017). Conclusion: Controlling for preoperative factors, EVAR is an independent predictor of lower 30 day mortality relative to open repair after RAAA. This supports the wider use of endovascular repair in all patients with RAAA.

Late conversion of endovascular to open repair of abdominal aortic aneurysms

BACKGROUND Failure of endovascular repair (EVAR) of an abdominal aortic aneurysm can result in significant risk of morbidity and mortality. We review our experience with late conversions to open repair. METHODS We conducted a retrospective database review to identify all EVAR procedures performed between 1997 and 2010 and the number converted to open repair at our university-affiliated medical centre. Late conversion was defined as those occurring at least 30 days after initial EVAR. RESULTS In all, 892 EVARs took place during the study period. Six patients (0.7%) required late conversion to open repair. Their mean age was 71 (range 58-83) years, and half were women. Half of the initial EVARs were for ruptured aneurysms. The median time to conversion was 15.6 (range 1.7-61.3) months. Indications for secondary conversion (50% urgent, 50% elective) included persistent type I endoleak (n = 3), combined type II and III endoleak (n = 1), graft thrombosis (n = 1) and aneurysm rupture (n = 1). Supraceliac clamping was required in most patients (67%), and the mean transfusion requirement was 2.6 units. Total endograft explantation occurred in 2 patients (33%), whereas partial or total endograft preservation occurred in 4 (67%). Median length of stay in hospital after conversion was 7 (range 6-73) days. There were no instances of early or in-hospital mortality following conversion. CONCLUSION Our EVAR experience includes a low rate of late conversion to open repair, with most conversions being a result of persistent aneurysm perfusion. Although technically challenging, late conversion can be safe. Our experience supports ongoing surveillance after EVAR.

Understanding Surgical Preference and Practice in Hemodialysis Vascular Access Creation

Understanding healthcare providers’ preferences, values, and beliefs around AVF eligibility is important to explain variability in practice. We conducted a survey of international surgeons, using hypothetical patient scenarios, to assess resources used, variables, perceived barriers, and absolute contraindications to access creation. A total of 134 surgeons completed the survey. Venous duplex ultrasound mapping (VDUM) was offered to all patients by 90% of US, 68% Canadian, and 63% European respondents. VDUM altered clinical decision less than 25% of the time for 33% American, 48% Canadian, and 85% European surgeons. Increased comorbidities and previous failed access were deterrents to AVF creation as was vessel size. Second choice access was the AV graft in the US and Europe and the catheter in Canada. Absolute contraindications to AVF creation included patient life expectancy <1 year, left ventricular ejection fraction (LVEF) <15%, and a history of dementia, while 42% surgeons reported no absolute contraindications. Perceived barriers included patient preferences, long wait times for surgery, and late referral to a Nephrologist. Significant variability exists in the surgical preoperative assessment of patients, and the eligibility criteria used for fistula creation. Understanding surgeons’ preferences can aid in establishing standardization for VA access eligibility, including surgical assessment.

Natural history of minimal aortic injury following blunt thoracic aortic trauma

BACKGROUND Endovascular repair of blunt traumatic thoracic aortic injuries (BTAI) is common at most trauma centres, with excellent results. However, little is known regarding which injuries do not require intervention. We reviewed the natural history of untreated patients with minimal aortic injury (MAI) at our centre. METHODS We conducted a retrospective database review to identify all patients with a BTAI between October 2008 and March 2010. The cohort comprised patients initially untreated because of the lesser degree of injury of an MAI. We reviewed initial and follow-up computed tomography (CT) scans and clinical information. RESULTS We identified 69 patients with a BTAI during the study period; 10 were initially untreated and were included in this study. Degree of injury included intimal flaps (n = 7, 70%), pseudoaneurysms with minimal hematoma (n = 2, 20%) and circumferential intimal tear (n = 1, 10%). Six (60%) patients were male, and the median age was 40 years. Duration of clinical follow-up ranged from 1 month to 6 years (median 2 mo) after discharge, whereas CT radiologic follow-up ranged from 1 week to 6 years (median 6 wk). Seven (70%) patients had complete resolution or stabilization of their MAI, 1 (10%) with circumferential intimal tear showed extension of the injury at 8 weeks postinjury and underwent successful repair, and 2 (20%) were lost to follow-up. CONCLUSION There appears to be a subset of patients with BTAI who require no surgical intervention. This includes those with limited intimal flaps, which often resolve. Radiologic surveillance is mandatory to ensure MAI resolution and identify any progression that might prompt repair.

Tuberculous Aneurysm of the Supraceliac Aorta: A Case Report

Significant vascular complications are rare following systemic infections with Mycobacterium tuberculosis (TB). This report describes a 33-year-old man who presented with a short history of abdominal discomfort and febrile episodes with no prior history of infection with TB. Ultrasound, CT scan, and aortography confirmed the presence of a pseudoaneurysm originating from the posterior aspect of the supraceliac aorta at the level of the diaphragm. Via a full thoracoabdominal approach, periaortic inflammatory tissue and the aortic wall itself were debrided, and repair of the pseudoaneurysm was achieved with a synthetic patch. Mycobacterium tuberculosis was isolated from the aortic wall, and anti-TB medications were instituted. Postoperatively the patient did well and was discharged after 14 days. As illustrated by this case, tuberculous mycotic aneurysms of the aorta are optimally treated with a combination of medical and surgical therapy, and early diagnosis is essential to ensure survival.

Midterm Results of the Zenith Endograft in Relation to Neck Length

BACKGROUND Successful endovascular repair of abdominal aortic aneurysms (AAAs) requires specific infrarenal neck anatomy to allow for a durable seal and fixation. This is a single-center study reviewing outcomes in relation to neck length after placement of a Zenith endograft. METHODS Retrospective single-center review of all AAAs electively repaired with a Zenith endograft during a recent 5-year period. Patients were divided into those with infrarenal necks 4-15 mm in length and those >15 mm using center line measurements. Clinical outcomes and follow-up computed tomography scans were reviewed. RESULTS Between 2003 and 2008, 318 patients underwent elective repair of an infrarenal AAA with the Zenith endograft. Of 318 patients, 68 (21.4%) had necks measuring 4-15 mm in length and 250 (79.5%) had necks measuring >15 mm. Overall early mortality was 0.9% (p = 0.11) and the rate of type II endoleaks was 19% (p = 0.11); neither differed between the groups. Four patients in each group had immediate proximal type I endoleaks, which resolved spontaneously in two patients in each group. The remaining two in each group required further intervention (two endovascular and two conversion to open repair). Type I endoleaks and reinterventions did not differ statistically between groups (p = 0.06). On further analysis, those patients requiring reintervention or conversion for type I endoleaks had other unattractive neck features (large diameter, angulation). There have been no instances of new type I endoleaks during 5-yearfollow-up period. CONCLUSION These midterm results indicate that patients with shorter infrarenal necks can be treated as effectively as those with longer necks with the Zenith endograft unless these necks are tortuous or wide.

Determination of Patient Preference for Location of Elective Abdominal Aortic Aneurysm Surgery

Objective: Aneurysm repair is centralized in higher volume centers resulting in reduced mortality, with longer travel distances. The purpose of this study is to explore patients’ preference between local care versus longer distances and lower mortality rates. Methods: Patients with abdominal aortic aneurysm (AAA) measuring 4 to 5 cm and living at least a 1-hour drive from our hospital were asked to assume it had grown to 5.5 cm, and repair was recommended with a mortality risk of 2%. The level of additional risk they would accept to undergo surgery locally was determined. Results: A total of 67 patients were surveyed. If mortality risk was equivalent at the local and regional hospitals, 44% preferred care at our tertiary center, while 56% preferred surgery locally. If perioperative mortality was increased at the local hospital, 9% preferred local surgery. Conclusions: The vast majority of patients with AAA will accept longer travel distances for care as long as it results in a reduction in perioperative mortality.