D. Kirk Lawlor

Cytokines contribute to early hepatic parenchymal injury and microvascular dysfunction after bilateral hindlimb ischemia.

PURPOSE Hepatic dysfunction may contribute to death from multiple organ dysfunction after abdominal aortic surgery. Several factors are likely responsible, and the purpose of this study was to determine whether the cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin 1 (IL-1) are involved in initiating this remote hepatic injury. METHODS In a normotensive rat model of 4-hour bilateral hindlimb ischemia/reperfusion (I/R), we measured systemic TNF-alpha and IL-1 levels throughout the I/R period. Rats were randomly assigned to either the 3-hour control group, the 3-hour I/R group, or the I/R group with administration of a polyclonal antibody (PAb) to TNF-alpha (I/R + TNF-alpha PAb). Direct evidence of lethal hepatocyte injury through the labeling of nuclei by propidium iodide (per 10(-1)mm(3)) and altered microvascular perfusion were assessed by using intravital microscopy. RESULTS Systemic TNF-alpha peaked at 83.97 pg/mL (P <.05, n = 5) at 30 minutes of reperfusion and returned to baseline in 60 to 90 minutes. No significant change in systemic IL-1 was detected (P <.05, n = 4). Alanine aminotransferase increased 2.5-fold in the I/R group through 3 hours of reperfusion (P <.05, n = 4), and TNF-alpha PAb did not attenuate this alanine aminotransferase increase (P <.05, n = 6). Lethal hepatocyte injury increased by 8-fold in the I/R group compared with the control group (P <.05, n = 5), whereas TNF-alpha PAb significantly reduced this injury (P <.05, n = 4). No regional differences in injury were noted within the acinus. Total perfusion within the microvascular unit did not drop; however, significant flow heterogeneity was observed. The proportion of continuously perfused sinusoids declined in the I/R group after 3 hours of reperfusion in both periportal (62.0 +/- 2.2, P <.05) and, to a lesser, although significant, degree, in the pericentral regions (73. 2 +/- 1.73, P <.05). CONCLUSION By scavenging extracellular TNF-alpha with a PAb, we provide direct evidence that TNF-alpha contributes to, but is not solely responsible for, early remote hepatocellular injury and microvascular dysfunction. The administration of TNF-alpha PAb reduced lethal hepatocyte injury in both regions of the acinus and also improved perfusion in the periportal region (76.8 +/- 5.41, P <.05), but not in the pericentral region. This suggests that TNF-alpha released during reperfusion mediates early remote hepatocellular injury and microvascular dysfunction after a remote ischemic insult.

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.

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.

Early results from a Canadian multicenter prospective registry of the Endurant stent graft for endovascular treatment of abdominal aortic aneurysms.

Purpose To report the early results of a multicenter registry of endovascular aneurysm repair (EVAR) using the Endurant stent-graft. Methods Patients having elective treatment of infrarenal abdominal aortic aneurysm (AAA) with the Endurant stent-graft at 3 Canadian centers were enrolled in a prospective registry between September 2008 and January 2010. In the 16-month period, 111 patients (90 men; mean age 75 years, range 53–93) were registered. Thirty-seven (33.3%) patients had challenging anatomy: short proximal aortic necks (n = 17), large diameter (>28 mm) aortic necks (n = 4), angulated (>60°) necks (n=3), and small (<15 mm) external iliac arteries (n=21). Outcomes evaluated included survival, endoleak, aneurysm expansion >5 mm, secondary intervention, stent-graft migration, and graft thrombosis. Results The overall technical success rate was 100%. Nineteen (17.1%) patients experienced perioperative complications. After a mean follow-up of 6 months (range 0.1–16), mortality in the series was 4.5%: 1 perioperative death (multisystem organ failure) and 4 (3.6%) late deaths (3 cardiac, 1 cancer). Clinical and imaging follow-up past the perioperative period were available in 107 (96.4%) and 99 (89.2%) patients, respectively. Among the latter, 9 (9.1%) had a type II endoleak on the first scan; 4 resolved spontaneously. Three (3.0%) patients developed graft limb thrombosis in follow-up; one required an intervention. There was no graft migration, aneurysm expansion, secondary intervention for endoleak, aneurysm rupture, or conversion. Conclusion Early results from this prospective multicenter registry indicate that the Endurant stent-graft is a safe option for elective EVAR in selected AAA patients. Longer follow-up is required to determine the durability of these outcomes.

The Role of Platelet-Rich Plasma in Inguinal Wound Healing in Vascular Surgery Patients

The objective was to determine whether incision application of platelet-rich plasma (PRP) will decrease postoperative wound complications in vascular surgery patients. A prospective, randomized trial randomized 81 incisions in 51 patients who underwent femoral artery exposure for elective revascularization procedures or endovascular abdominal aneurysm repairs. Incidence of diabetes, chronic renal failure, prosthetic grafts, body mass index (BMI), and steroid use did not differ. Using the ASEPSIS wound classification system, we found no difference in incidence of wound infection. Wound complications occurred in 9 (23%) of 40 of PRP group and 9 (22%) of 41 of non-PRP. Severe wound complications developed in 5 (13%) PRP and 6 (5%) of non-PRP (P = NS). In multivariate analysis, there were no predictors for wound infection. Groin wound complications rates are common in this patient group. Platelet-rich plasma did not decrease the incidence of groin wound complications in our patients

Endovascular Repair of Thoracic Aortic Disease: Early and Midterm Experience

Thoracic aorta disease remains a challenging problem, and despite improvements, open repair techniques are still associated with significant morbidity and mortality. This is a retrospective review of 53 consecutive patients with thoracic aortic pathology who were treated with endovascular repair between September 1998 and December 2004 at a tertiary-care hospital. Endovascular stent graft placement was performed on 23 elective and 30 emergent patients (34 male patients, mean age 66 years, 21 to 85 years). Completion angiography revealed no endoleak in 47 (89%) patients, a type I endoleak in 4 patients, and a type II endoleak in 2 patients. Operative 30-day mortality for elective aneurysms (n = 22), emergent aneurysms (n = 10), dissection (n = 3), penetrating aortic ulcers (n = 7), and trauma (n = 11) was 0%, 40%, 0%, 29%, and 9%, respectively. In total, 46 (87%) patients survived 30 days, and 36 (78.3%) of the survivors were discharged home free of complications. Two patients (4%) experienced paraplegia. Median follow-up was 22 months (1 to 72 months). Intermediate-term results revealed 41 (89%) patients free of endoleak, stent migration, or aneurysmal expansion. Two (4%) patients required reintervention with an additional stent graft. There were 2 (4%) patients with late aortic-related deaths and four (9%) patients with non—aorticrelated late deaths. Endovascular stent graft placement for thoracic aorta disease can be performed successfully and safely with good perioperative and intermediate-term outcomes. Stent graft complication and reintervention rates are low, whereas intermediate survival rates are good. Long-term efficacy still needs to be evaluated.

The association between a surgeon's learning curve with endovascular aortic aneurysm repair and previous institutional experience

The purpose of the present study was to determine whether an institution’s prior endovascular experience influenced the learning curve of subsequent surgeons. A prospective analysis of the initial 70 endovascular abdominal aortic aneurysm repair (EVAR) cases attempted by an individual surgeon was performed with the primary outcome variable being achievement and 30-day maintenance of initial clinical success. Along with standard statistical analyses, the cumulative sum failure method (CUSUM) was used to analyze the learning curve, with a predetermined acceptable failure rate of 10%. Seventy elective EVAR cases were performed by this surgeon during a 4-year period (2000-2004) (mean age, 73.7 ∓ 5.4 years; mean aneurysm diameter 63.3 ∓ 7.2 mm). Initial clinical success was achieved in 68 of 70 cases (97%), which differed significantly with that of our initial surgeon (88.5%, P = .01). Causes of failure in the present series included 1 early mortality (1.4%) and 1 case of conversion to open repair with no instances of type I endoleak or endograft limb thrombosis. Both surgeons’ cases were plotted sequentially with CUSUM curves revealing a significantly shorter learning curve for the second surgeon. Optimal results were achieved following 10 to 20 EVAR cases, as opposed to 60 cases in the initial series. Such an analysis confirms that as an institution’s experience with EVAR increases, an individual surgeon’s learning curve shortens considerably.

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.

Saccular Aneurysm of the Extracranial Internal Carotid Artery

While surgery for stenotic lesions of the internal carotid artery (ICA) remains a common procedure performed by vascular surgeons, aneurysmal disease in this area continues to present less frequently. It has been estimated that operations for carotid aneurysms may account for at most 2% of all carotid artery interventions. Although pseudoaneurysms following endarterectomy continues to be the most common pathology (in up to 58% of cases) several other aetiological processes are possible. These include atherosclerosis, fibromuscular dysplasia, trauma and carotid dissection. The natural history of these aneurysms is not entirely known as few centres have accumulated sufficient experience. However, in keeping with most published series, 43% of patients with ICA aneurysms presenting to the Texas Heart Institute suffered from symptoms related to cerebral ischemia. This relatively high risk of cerebral events has led many vascular surgeons to advocate intervention for most of these aneurysms. This report describes the presentation and subsequent successful surgical treatment of a large asymptomatic, atherosclerotic internal carotid aneurysm in an elderly women. Case Report