The reliability of differentiating neurogenic claudication from vascular claudication based on symptomatic presentation.

BACKGROUND: Intermittent claudication can be neurogenic or vascular. Physicians use a profile based on symptom attributes to differentiate the 2 types of claudication, and this guides their investigations for diagnosis of the underlying pathology. We evaluated the validity of these symptom attributes in differentiating neurogenic from vascular claudication. METHODS: Patients with a diagnosis of lumbar spinal stenosis (LSS) or peripheral vascular disease (PVD) who reported claudication answered 14 questions characterizing their symptoms. We determined the sensitivity, specificity and positive and negative likelihood ratios (PLR and NLR) for neurogenic and vascular claudication for each symptom attribute. RESULTS: We studied 53 patients. The most sensitive symptom attribute to rule out LSS was the absence of "triggering of pain with standing alone" (sensitivity 0.97, NLR 0.050). Pain alleviators and symptom location data showed a weak clinical significance for LSS and PVD. Constellation of symptoms yielded the strongest associations: patients with a positive shopping cart sign whose symptoms were located above the knees, triggered with standing alone and relieved with sitting had a strong likelihood of neurogenic claudication (PLR 13). Patients with symptoms in the calf that were relieved with standing alone had a strong likelihood of vascular claudication (PLR 20.0). CONCLUSION: The classic symptom attributes used to differentiate neurogenic from vascular claudication are at best weakly valid independently. However, certain constellation of symptoms are much more indicative of etiology. These results can guide general practitioners in their evaluation of and investigation for claudication.

CONTEXTE: La claudication intermittente peut avoir une étiologie neurogène ou vasculaire. Les médecins utilisent un profil fondé sur les particularités des symptômes pour distinguer l'une de l'autre et ceci oriente leur choix des méthodes de diagnostic de la pathologie sous-jacente. Nous avons évalué la validité de ces particularités des symptômes utilisées pour distinguer la claudication d'origine neurogène de la claudication d'origine vasculaire. MÉTHODES: Des patients atteints d'une sténose spinale lombaire (SSL) ou d'une maladie vasculaire périphérique (MVP) avérées qui se plaignaient de claudication ont réponduà 14 questions afin de caractériser leurs symptômes. Nous avons déterminé la sensibilité, la spécificité et les rapports de probabilité positifs et négatifs (RPP et RPN) à l'égard de la claudication neurogène ou vasculaire pour chacune des particularités des symptômes. RÉSULTATS: Notre étude a regroupé 53 patients. La particularité des symptômes dotée de la sensibilité la plus élevée pour ce qui est d'écarter le diagnostic de SSL a été l'absence de « déclenchement de la douleur à la simple station debout ¼ (sensibilité 0,97; RPN 0,050). Les données sur ce qui soulageait la douleur et sur la localisation des symptômes ont eu une faible portée clinique en ce qui a trait à la SSL et à la MVP. La présence d'une constellation de symptômes a donné lieu aux associations les plus solides : les patients qui manifestaient un signe du « panier d'épicerie ¼ positif et dont les symptômes étaient localisés au-dessus du genou, déclenchés par la station debout seule et soulagés en position assise présentaient une forte probabilité de claudication d'origine neurogène (RPP 13). Chez les patients dont les symptômes étaient localisés au mollet et qui étaient soulagés par la station debout, on notait une forte probabilité de claudication d'origine vasculaire (RPP 20,0). CONCLUSION: Considérés individuellement, les attributs classiques des symptômes utilisés pour distinguer la claudication d'origine neurogène de la claudication d'origine vasculaire sont au mieux faiblement valides. Toutefois, certaines constellations de symptômes éclairent bien davantage l'étiologie. Ces résultats peuvent guider l'omnipraticien dans son examen et dans son diagnostic de la claudication.

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.

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.

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.

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.

Midterm results of endovascular infrarenal abdominal aortic aneurysm repair in high-risk patients.

Short-term and midterm clinical outcomes after endovascular repair of abdominal aortic aneurysms (AAAs) have been well documented. Evaluation of longer term outcomes is now possible. Here we describe our initial 100 high-risk patients treated with endovascular aneurysm repair (EVAR), all with a minimum of 5 years of follow-up. A retrospective review of prospectively recorded data in a departmental database was undertaken for the first 100 consecutive EVAR patients with a minimum of 5 years (range, 60-105 months) of follow-up performed between December 1997 and June 2001. Information was obtained from surgical follow-up visits and family doctors' offices. Endovascular repair of AAA in high-risk patients can be achieved with acceptably low postoperative mortality and morbidity. Longer term results in this high-risk cohort suggest that EVAR is effective in preventing aneurysm-related deaths at 5 years and beyond. All late mortalities were due to patients' comorbid diseases.

Outcomes of hemodialysis-dependent patients following elective abdominal aortic aneurysm repair.

As hemodialysis-dependent patients have a shorter life expectancy it has been recently questioned whether they benefit from procedures such as abdominal aortic aneurysm (AAA) repair. The purpose of this study was to review our results with elective AAA repair in hemodialysis-dependent patients. During a recent 6-year period (1998-2003), 7 such patients underwent elective repair of their infrarenal aortic aneurysms. Mean age and aneurysm diameter were 71 years and 69 mm, respectively. Mean length of stay was 28.6 days including routine intensive care unit admission. Three patients underwent standard open repair, and 3 underwent endovascular repair. In the seventh patient iliac calcification precluded endograft delivery and resulted in conversion to open repair. Another endovascular patient suffered from perforation of her sigmoid colon. One- and 3-year survival rates in the entire cohort were 100% and 75%, respectively. The authors conclude that aneurysm repair in hemodialysis patients is warranted and life prolonging in appropriate risk patients, despite lengthy hospital stays. However, successful endovascular repair may be prevented by the severe arterial calcification in these patients.

Abdominal aortic aneurysms following orthotopic heart transplantation.

The purpose of these authors' study was to analyze their center's experience with orthotopic heart transplantation (OHT) and abdominal aortic aneurysms (AAA) with particular attention to corticosteroid dosing, hemodynamic parameters, and aneurysm growth rate. A retrospective review of all patients (453) who underwent OHT at their university-affiliated medical center over an 18-year period (1981-1999) was undertaken. Nine (2%) patients who developed AAAs were identified and aneurysm growth was correlated with corticosteroid immunosuppression and hemodynamic parameters. The mean age of OHT patients was 44.5 +/-15 years and the majority were males (371 males, 82%). Median follow-up was 5.7 years. Ischemic cardiomyopathy (IC) was the most common indication for transplantation (45.5% of patients). All AAA patients were male (p=0.157), with a mean age of 58.4 +/-4.8 years (p=0.001), and had undergone OHT for IC (p=0.001). Mean arterial blood pressure and ejection fraction in the AAA patients had increased from pretransplant values of 107 mm Hg and 14.3 +/-5.7% to 142 mm Hg (p=0.017) and 54.1 +/-14.1% (p<0.001), respectively, before aneurysm repair. Mean aneurysm diameter at the time of repair was 6.0 +/-0.8 cm, and the average growth rate was 1.2 +/-0.4 cm/year in the 4 patients in whom it could be measured. Aneurysm repair was performed urgently in 2 patients and electively in 7 patients with 1 early postoperative death (11%). The extent of corticosteroid immunosuppression, corticosteroid pulses, and total corticosteroid dosing did not correlate with the rate of aneurysm growth. Improved hemodynamics and progressive posttransplant hypertension may contribute to aneurysm formation and growth in this group of patients.

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.

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.

Spontaneous aortic arch thrombus presenting as acute critical limb ischemia.

We report a case of a 52-year-old male who presented with acute leg ischemia and underwent successful femoral embolectomy and fasciotomies. Investigations revealed a pedunculated mass in the aortic arch, floating under the innominate and left common carotid arteries. Urgent resection was performed through a longitudinal aortotomy with deep hypothermic circulatory arrest and axillary artery perfusion to reveal a 2.5 x 1.5 cm pedunculated mass attached to the posterior aspect of the arch that was resected. Histology revealed thrombus material prompting lifelong systemic anticoagulation. On 3 months follow-up, the patient had returned to normal activities and computed tomography confirmed complete resection without recurrence. This case study demonstrates that spontaneous thrombus formation is possible in high-flow vascular regions such as the aortic arch and also confirms the importance of evaluating central sources of thromboemboli in patients presenting with acute limb ischemia. Urgent surgical removal is recommended and can be performed safely.

Recurrent aortic aneurysms in Behçet disease.

The following is a case of a 22-year-old male with recurrent thoracic aneurysms with several constitutional symptoms, including gastrointestinal discomfort, irritable bowel syndrome, lactose intolerance, and a 2-week history of severe lower back pain. The patient underwent an initial thoracoabdominal repair of a visceral aneurysm followed by endovascular repair of a recurrent thoracic pseudoaneurysm. The etiology of the visceral aneurysm was initially hypothesized to be mycotic; however, further information revealed signs and symptoms consistent with the diagnostic criteria for Behçet disease (BD). We suggest that BD be considered in younger patients who present with an aortic aneurysm. Although open repair is the traditional approach for arterial lesions in BD, the role for endovascular intervention should be considered as it represents a surgical repair with a significant reduction in morbidity.

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.

Ruptured mycotic abdominal aortic aneurysm secondary to Mycobacterium bovis after intravesical treatment with bacillus Calmette-Guérin.

Bacillus Calmette-Guérin (BCG) is a live attenuated strain of Mycobacterium bovis that has proven effective in the treatment of early-stage bladder cancer. Although intravesical therapy with BCG is generally considered safe, serious complications including hematuria, granulomatous pneumonitis, hepatitis, and life-threatening BCG sepsis are well known. BCG-related vascular infections are rarely reported. We present a case of a ruptured abdominal aortic aneurysm secondary to M bovis infection 2 years after intravesical instillation of BCG and review the related literature.

Learning curve analysis of thoracic endovascular aortic repair in relation to credentialing guidelines.

OBJECTIVE: Recently, practice guideline documents have recommended the completion of different levels of interventional experience and 5 or 10 thoracic endovascular aortic cases prior to surgeon credentialing. This study's purpose was to determine whether these requirements are valid by reviewing three surgeons' learning curves with thoracic aortic endovascular repairs. METHODS: Between 1998 and 2006, 67 patients underwent emergent or elective endovascular repair of thoracic aortic pathologies by one of three vascular surgeons with extensive experience with catheter manipulation and abdominal aortic endografts. Following standard retrospective review, each surgeon's learning curve was analyzed using the cumulative sum failure method with a target success rate of 95% derived from the literature. The main outcome variable was primary technical success. RESULTS: These 67 patients presented with several pathologies including elective (n = 31) and ruptured (n = 11) thoracic aortic aneurysms, acute dissections or aortic ulcers (n = 10), and acute blunt thoracic aortic trauma (n = 15). The mean age was 65 (range: 20 to 90) and the early (30 day) mortality rate was 19.4% in urgent cases (n = 36) and 0% in elective cases (n = 31). Paraplegia occurred in two patients (3%). Primary technical success was achieved in 62 cases (92.5%) and did not differ between surgeons (92.6%, 91.3%, 94.1%, respectively; P = .9). Each surgeon's cases were plotted sequentially and the resulting learning curves were similar. Although acceptable outcomes were obtained throughout the study period, improved results, compared with the target success rate, were not achieved until each surgeon treated 5 to 10 patients. CONCLUSION: This study supports the case volume requirements of the Society for Vascular Surgery credentialing guidelines, which also requires extensive catheter and guidewire experience. With this background in catheter manipulation and endovascular abdominal aortic repair, surgeons can achieve optimal outcomes with thoracic aortic lesions following 5 to 10 cases.

Objective scoring systems of medical risk: a clinical tool for selecting patients for open or endovascular abdominal aortic aneurysm repair.

BACKGROUND: Objective scoring systems have been developed for risk stratification of open infrarenal aneurysm repair. To date, none have been applied for the selection of patients who would most benefit from either an open or an endovascular approach. This study assessed the utility of comorbidity-based objective scoring systems for defining subgroups of patients who might most benefit from open or endovascular aneurysm repair. METHODS: A retrospective database review was performed for the period January 1999 to December 2004 to identify patients who had undergone elective open aneurysm repair (open repair) or elective endovascular aneurysm repair (EVAR). Validation of the Glasgow Aneurysm Score (GAS), the Modified Leiden Score (M-LS), and the Modified Comorbidity Severity Score (M-CSS) was performed for perioperative mortality risk in the open repair group. GAS, M-LS, and M-CSS were then calculated for the EVAR group. Differences in open repair vs EVAR mortalities were evaluated. RESULTS: During the time period, 558 patients underwent open repair and 304 underwent EVAR. Overall mortality was 4.7% for open repair patients and 2.0% for EVAR. All three scoring systems were validated to our open repair data set (C statistic: GAS, 0.72; M-LS, 0.71; M-CSS, 0.74). A score was calculated for each system that separated patients into groups of either low or high risk of death for open repair. This score (cut point) was 76.5 for the GAS, 5.2 for the M-LS, and 8 for the M-CSS. Analysis of the EVAR population revealed that patients at low medical risk for open repair did not derive statistically significant mortality benefit with EVAR; however, patients at high medical risk for open repair derived significant benefit from EVAR (GAS>76.5 mortality: open repair, 7.8%; EVAR, 1.9% [P<.01]; M-LS mortality: open repair, 8.1%; EVAR, 2.5% [P<.01]; and M-CSS mortality: open repair, 10.3%; EVAR, 3.4% [P<.025]). Despite a very small number of deaths (n=6), receiver operator curve analysis identified M-LS and M-CSS as having some predictive ability for mortality risk with EVAR (C statistic: M-LS, 0.70; M-CSS, 0.69). CONCLUSION: Three validated objective scoring systems can be used to categorize patients into two groups of medical risk: one that has excellent outcome with open repair and derives no early mortality benefit from EVAR, and another that has significant mortality with open repair and derives important benefit with EVAR.

The effect of patient transfer on outcomes after rupture of an abdominal aortic aneurysm.

OBJECTIVE: Centralization of vascular surgery services has resulted in patients being transferred longer distances for treatment of life-threatening conditions. The purpose of this study was to determine whether patient transfer adversely affects the survival of people with a ruptured abdominal aortic aneurysm (RAAA). METHODS: We performed a retrospective review of all patients undergoing attempted repair of an RAAA at our centre, over a recent 3.5-year period (August 2000-December 2003). Patients were divided into those presenting directly to our centre and those transferred from another hospital. The main outcome variable was in-hospital or 30-day mortality, with secondary variables including time to surgical treatment, mortality in the first 24 hours and length of hospitalization. RESULTS: Eighty-one patients (73% men) underwent attempted open repair of an RAAA at our centre during this period. Twenty-four patients (29.6%) presented directly to our hospital, while 57 (70.4%) were transferred from another institution. The overall mortality rate was 53%. Although transferred patients took twice as long as direct patients to get to the operating room (6.3 v. 3.2 h, p=0.03), there was no difference in mortality between the 2 groups (50% v. 54%, p=ns). However, deaths of transferred patients were more likely to occur in the first 24 postoperative hours, compared with direct patients (40% v. 33%, p<0.05). Neither mean intensive care unit stay (5.8 and 8.1 d) nor total hospitalization (20.9 and 18.8 d) differed between the 2 groups. CONCLUSIONS: Although the transfer of patients with RAAA results in a treatment delay, it does not adversely affect the already high mortality rates associated with this condition. These results may be attributed to a preselection of patients who are able to tolerate such a delay.

Prevention of contrast-induced nephropathy in vascular surgery patients.

Presently, only hydration and N-acetylcysteine have been shown to be effective in decreasing the incidence of radiographic contrast-induced nephropathy. We investigated the role of N-acetylcysteine and various hydration protocols in vascular surgery patients undergoing angiography. A single-center, randomized, placebo-controlled trial was conducted in patients with stable, preexisting renal dysfunction undergoing elective, outpatient angiography. Patients were randomized to outpatient oral hydration and N-acetylcysteine, inpatient hydration plus N-acetylcysteine, or our standard therapy of inpatient intravenous hydration alone. Two of twenty-eight (7%) patients who received outpatient oral hydration and N-acetylcysteine developed contrast-induced nephropathy, while two of 25 (8%) who recieved inpatient hydration plus N-acetylcysteine developed contrast-induced nephropathy and two of 25 (8%) who received standard therapy of inpatient intravenous hydration alone developed contrast-induced nephropathy. There was no statistical difference in incidence of contrast-induced nephropathy between the groups. No statistically significant independent risk factors were identified among the patients who developed contrast-induced nephropathy. N-Acetylcysteine did not confer additional benefit to patients treated with inpatient intravenous hydration. Outpatient oral hydration plus N-acetylcysteine was as effective at preventing contrast-induced nephropathy as inpatient therapies and avoided costly hospital admission.

Comparison of renal function after endovascular aneurysm repair with different transrenally fixated endografts.

OBJECTIVE: Transrenal fixation of abdominal aortic endografts may provide a more secure proximal attachment with few deleterious effects with respect to renal function. This study's purpose was to determine whether different metals used in two commercially available endografts (Cook Zenith and Medtronic Talent) result in different effects on renal function when placed across renal ostia. METHODS: A total of 140 consecutive patients, between August 2003 and April 2005, who underwent elective endovascular repair of an aortic aneurysm with a nitinol or stainless steel-based endograft with transrenal fixation were reviewed with a mean follow-up period of 5.5 months (range, 1-22 months). The main outcome variable was the percentage change in creatinine clearance (CrCl), which was determined before surgery and at the most recent follow-up. Multiple regression analysis was performed to analyze the contribution of various factors to any deterioration in renal function. RESULTS: The 140 patients were predominantly male (86%), with a mean age of 75 years (range, 56-92) and a mean aneurysm diameter of 62 mm (range, 42-110 mm). The mean intraoperative contrast use was 67 mL (range, 45-160 mL), and after surgery these patients received a mean of 3 surveillance computed tomographic scans (range, 1-7). Nineteen cases (13.6%) required deliberate accessory renal artery coverage. CrCl did not change significantly after surgery; the mean change in CrCl at the end of follow-up was a 2.5% decrease. There was no difference in the reduction in CrCl between endograft types. Only 14.3% of patients experienced a greater than 20% decrease in CrCl. Multiple regression analysis failed to show a relationship between change in renal function and age, sex, aneurysm diameter, infrarenal neck dimensions, endograft type, coverage of accessory renal arteries, intraoperative contrast volume, preoperative CrCl, and postoperative computed tomographic scans. Length of follow-up was an independent predictor (P = .04). CONCLUSIONS: Transrenal endograft fixation results in little deterioration in renal function during intermediate follow-up. The few patients who do experience a decline in renal function do so independently of any features related to the initial endovascular repair, and there is no difference in renal deterioration between endografts with nitinol and stainless steel transrenal bare metal stents.

Gender differences in relative dilatation of abdominal aortic aneurysms.

It has been postulated that gender differences in abdominal aortic aneurysm (AAA) rupture risk are due to variation in proportional dilatation. This study's purpose was to examine differences in relative dilatation of AAAs as related to rupture risk and repair thresholds. During a recent 20-month period (August 2003-March 2005), all patients receiving elective endovascular repair of an AAA underwent computer-generated computed tomographic measurements, including suprarenal aortic diameter (D1) and maximum aneurysm diameter (D3). As a measure of proportional dilatation, a D3/D1 ratio was calculated for each patient and compared between genders. Values for males and females were plotted separately (D3 vs. D3/D1), and the resulting linear regression equations allowed for the comparison of proportional dilatation of aneurysms between genders. In 129 patients (108 males, 21 females), mean D3 did not differ between genders (62 +/- 9.0 vs 63.4 +/- 10.8 mm, p = 0.89), while relative dilatation (D3/D1) was significantly greater in females compared to males (2.82 +/- 0.52 vs. 2.55 +/- 0.42, p = 0.02). Linear regression analysis allowed for comparison of D3 as a function of D3/D1 and correlated a 55 mm AAA in males with one of 52 mm in females. These differences became greater with increasing AAA diameters (e.g., 60 and 70 mm AAAs in a male were proportionally similar to 56 and 62 mm AAAs in a female). AAAs of equal diameter represent a greater proportional dilatation in females than in males. This supports the recommendation for a smaller aneurysm diameter (52 mm) threshold for repair in females rather than the commonly used 55 mm threshold in males. Also, these data suggest that the gender difference in rupture risk widens exponentially as aneurysm diameter, and thereby proportional dilatation, increases above this repair threshold.