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Abstract| Volume 44, ISSUE 5, P524-526, November 2012

Selected Abstracts from the November Issue of the Journal of Vascular Surgery

        Impact of chronic kidney disease on outcomes after abdominal aortic aneurysm repair

        Virendra I. Patel, Robert T. Lancaster, Shankha Mukhopadhyay, Nathan J. Aranson, Mark F. Conrad, Glenn M. LaMuraglia, Christopher J. Kwolek, Richard P. Cambria
        Objective: Chronic kidney disease (CKD) is associated with increased morbidity and death after open abdominal aortic aneurysm (AAA) repair (OAR). This study highlights the effect of CKD on outcomes after endovascular AAA (EVAR) and OAR in contemporary practice.
        Methods: The National Surgical Quality Improvement Program (NSQIP) Participant Use File (2005-2008) was queried by Current Procedural Terminology (American Medical Association, Chicago, Ill) code to identify EVAR or OAR patients, who were grouped by CKD class as having mild (CKD class 1 or 2), moderate (CKD class 3), or severe (CKD class 4 or 5) renal disease. Propensity score analysis was performed to match OAR and EVAR patients with mild CKD with those with moderate or severe CKD. Comparative analysis of mortality and clinical outcomes was performed based on CKD strata.
        Results: We identified 8701 patients who were treated with EVAR (n = 5811) or OAR (n = 2890) of intact AAAs. Mild, moderate, and severe CKD was present in 63%, 30%, and 7%, respectively. CKD increased (P < .01) overall mortality, with rates of 1.7% (mild), 5.3% (moderate), and 7.7% (severe) in unmatched patients undergoing EVAR or OAR. Operative mortality rates in patients with severe CKD were as high as 6.2% for EVAR and 10.3% for OAR. Severity of CKD was associated with increasing frequency of risk factors; therefore, propensity matching to control for comorbidities was performed, resulting in similar baseline clinical and demographic features of patients with mild compared with those with moderate or severe disease. In propensity-matched cohorts, moderate CKD increased the risk of 30-day mortality for EVAR (1.9% mild vs 3.2% moderate; P = .013) and OAR (3.1% mild vs 8.4% moderate; P < .0001). Moderate CKD was also associated with increased morbidity in patients treated with EVAR (8.3% mild vs 12.8% moderate; P < .0001) or OAR (25.2% mild vs 32.4% moderate; P = .001). Similarly, severe CKD increased the risk of 30-day mortality for EVAR (2.6% mild vs 5.7% severe; P = .0081) and OAR (4.1% mild vs 9.9% severe; P = .0057). Severe CKD was also associated with increased morbidity in patients treated with EVAR (10.6% mild vs 19.2% severe; P < .0001) or OAR (31.1% mild vs 39.6% severe; P = .04).
        Conclusions: The presence of moderate or severe CKD in patients considered for AAA repair is associated with significantly increased mortality and therefore should figure prominently in clinical decision making. The high mortality of AAA repair in patients with severe CKD is such that elective repair in such patients is not advised, except in extenuating clinical circumstances.

        No increased mortality with early aortic aneurysm disease

        Matthew Mell, Julie J. White, Bradley B. Hill, Trevor Hastie, Ronald L. Dalman
        Objective: In addition to increased risks for aneurysm-related death, previous studies have determined that all-cause mortality in abdominal aortic aneurysm (AAA) patients is excessive and equivalent to that associated with coronary heart disease. These studies largely preceded the current era of coronary heart disease risk factor management, however, and no recent study has examined contemporary mortality associated with early AAA disease (aneurysm diameter between 3 and 5 cm). As part of an ongoing natural history study of AAA, we report the mortality risk associated with presence of early disease.
        Methods: Participants were recruited from three distinct health care systems in Northern California between 2006 and 2011. Aneurysm diameter, demographic information, comorbidities, medication history, and plasma for biomarker analysis were collected at study entry. Survival status was determined at follow-up. Data were analyzed with t tests or χ2 tests where appropriate. Freedom from death was calculated via Cox proportional hazards modeling; the relevance of individual predictors on mortality was determined by log-rank test.
        Results: The study enrolled 634 AAA patients; age 76.4 ± 8.0 years, aortic diameter 3.86 ± 0.7 cm. Participants were mostly male (88.8%), not current smokers (81.6%), and taking statins (76.7%). Mean follow-up was 2.1 ± 1.0 years. Estimated 1- and 3-year survival was 98.2% and 90.9%, respectively. Factors independently associated with mortality included larger aneurysm size (hazard ratio, 2.12; 95% confidence interval, 1.26-3.57 for diameter >4.0 cm) and diabetes (hazard ratio, 2.24; 95% confidence interval, 1.12-4.47). After adjusting for patient-level factors, health care system independently predicted mortality.
        Conclusions: Contemporary all-cause mortality for patients with early AAA disease is lower than that previously reported. Further research is warranted to determine important factors that contribute to improved survival in early AAA disease.

        Synchronous and metachronous thoracic aneurysms in patients with abdominal aortic aneurysms

        Rabih A. Chaer, Rogerio Vasoncelos, Luke K. Marone, George Al-Khoury, Robert Y. Rhee, Jae S. Cho, Michel S. Makaroun
        Objective: Although the association of thoracic aortic aneurysm (TAA) with abdominal aortic aneurysm (AAA) is known, the exact magnitude of the association has not been described. Our goal was to quantify the incidence of TAA in patients with an AAA and assess predictive factors for its diagnosis.
        Methods: This was a retrospective review of all patients diagnosed with AAA from 2000-2008. The subsequent development or diagnosis of a TAA was noted and the association between AAA and TAA described.
        Results: A total of 2196 patients with an AAA were reviewed. 1082 (49.3%) had a chest computed tomography (CT) during follow-up. 117 patients (10.8%) had a synchronous and 136 (12.6%) a metachronous TAA. Mean time to diagnosis was 2.3 years. Mean diameter was 4.7 ± 1.4 cm for AAA, and 4.7 ± 1.0 for TAA. Indications for the chest CT were variable. Most common were AAA (15%), pulmonary embolus (14%), and lung cancer (11%). Only 38% of AAAs and 14% of TAAs were repaired during the study period. Of all patients with known AAA who were found to have a TAA, 61/253 (24%) underwent repair, had a rupture, or had a TAA >5.5 cm. At a mean follow-up of 43.6 months, there were 79 deaths (7%): 7 AAA-related and 13 from TAA ruptures. Predictors of TAA diagnosis by logistic regression include African American race (odds ratio [OR] = 1.8; P = .02), family history of TAA (OR = 7.6; P = .04), hypertension (OR = 1.7; P = .006), and obesity (OR = 1.7; P = .006). Diabetes, infrarenal AAA location, and smoking have a negative association.
        Conclusions: TAAs are relatively common in patients with AAA. Routine or targeted screening with a chest CT at the time of AAA diagnosis may be indicated.

        Brain computed tomography perfusion may help to detect hemodynamic reconstitution and predict intracerebral hemorrhage after carotid stenting

        Shy-Chyi Chin, Chien-Hung Chang, Ting-Yu Chang, Ko-Lun Huang, Tai-Cheng Wu, Jr-Rung Lin, Yeu-Jhy Chang, Tsong-Hai Lee
        Objective: We wanted to examine whether brain computed tomography (CT) perfusion can help to detect the reconstitution of cerebral hemodynamics and predict intracerebral hemorrhage (ICH) after carotid stenting.
        Methods: From September 2002 to October 2009, data of 114 patients with carotid intervention were prospectively collected, and we retrospectively identified a total of 108 consecutive patients with unilateral carotid stenting. Brain CT perfusion was studied at three time points: 1 week before, and 1 week and 6 months after stenting. Cerebral blood volume (CBV), cerebral blood flow, and time to peak (TTP) of brain CT perfusion were examined at cortical and subcortical areas of middle cerebral artery (MCA) and posterior cerebral artery territory. The CBV, cerebral blood flow, and TTP ratios of stenting side/nonstenting side were used for comparison. The flow direction of ophthalmic artery was detected by sonography, and the presence of anterior communicating artery was examined on prestenting cerebral angiogram.
        Results: After carotid stenting, CBV and TTP ratios improved significantly in both MCA cortical and subcortical areas in patients with unilateral carotid stenosis (P < .01) but not in patients with bilateral carotid stenosis. Patients with reversed ophthalmic flow had better improvement of TTP in both MCA and posterior cerebral artery territories (P < .05) than patients with forward flow. However, no significant difference was found between patients with and patients without anterior communicating artery collateral (P > .05). The prestenting TTP ratio in MCA subcortical area was significantly higher in patients with poststenting ICH than patients without ICH (P = .0191).
        Conclusions: Cerebral hemodynamics can be reconstituted within a few days after carotid revascularization, especially in patients with reversed ophthalmic flow. Prolonged TTP in prestenting MCA subcortical area may suggest a high risk of poststenting ICH.

        Extracranial-intracranial bypass: Resurrection of a nearly extinct operation

        Ryan M. Gobble, Han Hoang, Jafar Jafar, Mark Adelman
        Background: Giant intracranial artery aneurysms (GIAAs) are often not amenable to neurosurgical clipping or endovascular coiling. Extracranial-intracranial (EC-IC) bypass, a procedure that has been essentially abandoned for the treatment of intracranial ischemic disease, followed by parent vessel occlusion, is often successful in treating these aneurysms. Vascular surgeons should be familiar with this operation, especially in centers with neurosurgical capability.
        Methods: A retrospective review of patients treated from 1990 to 2010 at New York University Medical Center was performed. Office and hospital records of all patients identified were reviewed with attention to the age and sex of the patient, presenting symptoms, preoperative testing, procedure performed, type of bypass conduit, graft patency, intraoperative and postoperative complications, length of follow-up, and overall outcome. EC-IC bypass was performed using a graft of great saphenous vein (GSV) or radial artery (RA). The vascular surgeon harvested the vascular conduit, tunneled the graft, and performed the extracranial anastomosis, and the intracranial anastomosis was performed by the neurosurgeon.
        Results: A total of 36 patients (14 men, 22 women) underwent 37 EC-IC bypasses with 34 GSV and three RA grafts. The median age was 57 years (interquartile range, 49-66 years), and the median follow-up was 53 months (interquartile range, 29-77 months). Aneurysm location was the internal carotid artery in 30 patients, the basilar artery in three, and the middle cerebral artery in four. All 37 aneurysms were excluded from the cerebral circulation, with 33 grafts remaining patent at follow-up, as determined by serial cerebral or magnetic resonance angiogram. At follow-up, 33 of 34 of the GSV grafts (88%) and three of three (100%) of the RA grafts were patent. There were two deaths (5.6%), despite patent grafts. Postoperative graft occlusion led to homonymous hemianopsia in one patient and temporary hemiparesis in another (5.6%). Graft occlusions were asymptomatic in two patients.
        Conclusions: EC-IC bypass is a safe and effective treatment for GIAAs, with acceptable rates of morbidity (5.6%), mortality (5.6%), and graft patency (89.2%). We suggest that the technique described in this report should be routinely used for treatment of GIAAs in centers where neurosurgery and vascular surgery services are available and should be considered a standard procedure in the armamentarium of the vascular surgeon.

        The impact of diabetes on perioperative outcomes following lower-extremity bypass surgery

        Jessica B. Wallaert, Brian W. Nolan, Julie Adams, Andrew C. Stanley, Jens Eldrup-Jorgensen, Jack L. Cronenwett, Philip P. Goodney
        Objective: The effect of diabetes type (noninsulin dependent vs insulin dependent) on outcomes after lower extremity bypass (LEB) has not been clearly defined. Therefore, we analyzed associations between diabetes type and outcomes after LEB in patients with critical limb ischemia.
        Methods: We performed a retrospective analysis of 1977 infrainguinal LEB operations done for critical limb ischemia between 2003 and 2010 within the Vascular Study Group of New England. Patients were categorized as nondiabetic (ND), noninsulin dependent diabetic (NIDD), or insulin-dependent diabetic (IDD) based on their preoperative medication regimen. Our main outcome measures were in-hospital mortality and major adverse events (MAEs) – a composite outcome, including myocardial infarction, dysrhythmia, congestive heart failure, wound infection, renal insufficiency, and major amputation. We compared crude and adjusted rates of mortality and MAEs using logistic regression across diabetes categories.
        Results: Overall, 41% of patients were ND, 28% were NIDD, and 31% were IDD. Crude rates of in-hospital mortality were similar across these groups (1.7% vs 3.1% vs 2.1%; P = .211). Adjusted analyses accounting for differences in patient characteristics showed that diabetes is not associated with increased risk of in-hospital mortality. However, type of diabetes was associated with a higher risk of MAEs in both crude (15.1% for ND; 21.1% for NIDD; and 25.2% for IDD; P < .001) and adjusted analyses (odds ratio for NIDD, 1.41; 95% confidence interval, 1.2-1.7; odds ratio for IDD, 1.53; 95% confidence interval, 1.3-1.8).
        Conclusions: Diabetes is a significant contributor to the risk of postoperative complications after LEB surgery, and insulin dependence is associated with higher risk. Quality measures aimed at limiting complications after LEB may have the most impact if these initiatives are focused on patients who are IDD.

        Comparison of vein valve function following pharmacomechanical thrombolysis vs simple catheter-directed thrombolysis for iliofemoral deep vein thrombosis

        David Vogel, M. Eileen Walsh, John T. Chen, Anthony J. Comerota
        Background: Successful catheter-directed thrombolysis (CDT) for iliofemoral deep vein thrombosis (IFDVT) reduces post-thrombotic morbidity and is a suggested treatment option by the American College of Chest physicians for patients with IFDVT. Pharmacomechanical thrombolysis (PMT) is also suggested to shorten treatment time and reduce the dose of plasminogen activator. However, concern remains that mechanical devices might damage vein valves. The purpose of this study is to examine whether PMT adversely affects venous valve function compared to CDT alone in IFDVT patients treated with catheter-based techniques.
        Methods: Sixty-nine limbs in 54 patients (39 unilateral, 15 bilateral) who underwent catheter-based treatment for IFDVT form the basis of this study. Lytic success and degree of residual obstruction were analyzed by reviewing postprocedural phlebograms. All patients underwent bilateral postprocedure duplex to evaluate patency and valve function. Phlebograms and venous duplex examinations were interpreted in a blinded fashion. Limbs were analyzed based on the method of treatment: CDT alone (n = 20), PMT using rheolytic thrombolysis (n = 14), and isolated pharmacomechanical thrombolysis (n = 35). The validated outcome measures were compared between the treatment groups.
        Results: Sixty-nine limbs underwent CDT with or without PMT. The average patient age was 47 years (range 16-78). Venous duplex was performed 44.4 months (mean) post-treatment. Of the limbs treated with CDT with drip technique, 65% demonstrated reflux vs 53% treated with PMT (P = .42). There was no difference in long-term valve function between patients treated with rheolytic and isolated pharmacomechanical thrombolysis. In the bilateral group, 87% (13/15) demonstrated reflux in at least one limb. In the unilateral group, 64% (25/39) had reflux in their treated limb and 36% (14/39) in their contralateral limb. There was no correlation effect of residual venous obstruction on valve function, although few patients had >50% residual obstruction.
        Conclusions: In patients undergoing catheter-based intervention for IFDVT, PMT does not adversely affect valve function compared with CDT alone. A higher than expected number of patients had reflux in their uninvolved limb.

        Analysis of the treatment of congenital vascular malformations using a multidisciplinary approach

        Michael E. Lidsky, Jovan N. Markovic, Michael J. Miller, Cynthia K. Shortell
        Background: Vascular malformations are a rare and complex group of lesions which may present serious pitfalls in diagnosis and management. We sought to evaluate the efficacy and safety of our imaging protocol and therapeutic algorithm in the treatment of low-flow and high-flow vascular malformations in a large series of patients.
        Methods: A prospective database of all patients treated by the multidisciplinary vascular malformation team at our institution between 2006 and 2011 was reviewed. Management decisions were based on patients' clinical profile as well as critical lesion characteristics, and included conservative care, sclerotherapy, embolization, surgical resection, or a combination of these modalities. Treatment goals and expectations were established by the patient and physician at the time of initial evaluation. An outcomes grading system based on patient- and physician-derived treatment goals and assessment of response to management was applied (1 = worse; 2 = unchanged, 3 = significantly improved, 4 = completely resolved), and postprocedural complications were identified.
        Results: The 136 vascular malformations in 135 patients included 59 (43.7%) males and 76 (56.3%) females, ranging in age from under 1 year to 68 years (mean, 25.3 ± 17.0 years). In order to facilitate application of the therapeutic algorithm, all patients underwent dynamic contrast-enhanced magnetic resonance imaging to determine critical lesion characteristics, including flow quality and lesion extension. Of the 105 low-flow vascular malformations (LFVM), 23 (21.9%) were managed conservatively, 38 (36.2%) were treated with sclerotherapy (sodium tetradecyl sulfate, polidocanol, and/or ethanol), 18 (17.1%) were surgically resected, and eight (7.6%) were managed with a combination of modalities. Of the 31 high-flow vascular malformations (HFVM), eight (25.8%) were managed conservatively, eight (25.8%) were treated with transcatheter arterial embolization, six (19.4%) required embolization followed by sclerotherapy, and five (16.1%) were primarily resected. Patients in all groups managed conservatively had minimal alteration in status. Response to sclerotherapy in the LFVM group resulted in improvement in 32 (84.2%) patients, surgical resection resulted in improvement in 16 (88.9%) patients, and combination therapy resulted in improvement in eight (100%) patients. Treatment with embolization in the HFVM group resulted in improvement in seven (87.5%) patients, while combination therapy resulted in improvement in six (100%), and surgical resection led to improvement in four (80%). Complications were observed in six (6.8%) patients treated for LFVMs (0 with sodium tetradecyl sulfate or polidocanol, four with ethanol, two with resection), and two (7.4%) patients treated for HFVMs with embolization or combination therapy.
        Conclusions: In this large cohort of vascular malformation patients, implementation of the proposed diagnostic and therapeutic algorithms in a multidisciplinary setting resulted in favorable outcomes with an acceptable complication rate in this challenging patient population.

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