A reliable method for renal volume measurement and its application in fenestrated endovascular aneurysm repair.

OBJECTIVE: Renal volume has been shown to correlate with renal function. Renal volume and renal function both decline steadily in the sixth decade of life and beyond. We sought to assess (1) the inter-rater reliability for manually measuring renal volume using computed tomography and (2) change in renal volume over time as it relates to renal function in fenestrated endovascular aortic aneurysm repair (FEVAR). METHODS: This study was conducted as part of a physician-sponsored investigational new device (#NCT01538056). First, 30 consecutive kidneys of preoperative FEVAR patients were independently measured by two raters using manual segmentation and three-dimensional modeling software. Renal volumes were calculated and compared. Intraclass correlation was calculated between the two observers. Second, renal volumes were then recorded for 85 patients undergoing FEVAR with follow-up out to 5 years. Demographic data, comorbidities, creatinine, glomerular filtration rate (GFR), renal artery stenosis or occlusion, and bilateral renal volume measurements were analyzed. Multivariate analysis was performed to delineate association of these variables with total renal volume (TRV). RESULTS: The intraclass correlation coefficient for our renal volume measurements was 0.97 (95% confidence interval, 0.81-0.99), indicating excellent correlation. Renal volume was strongly correlated with GFR. Our multivariate analysis model predicts a 17.9 mL/min increase in GFR with each 20% increase in TRV. After adjustment for all other known correlates of renal function, renal volume remained as the only significant predictor of renal function. CONCLUSIONS: Renal volume can be measured with high reliability using manual segmentation and computed tomography scans. In our baseline analysis, TRV was strongly correlated with renal function. These findings support the potential for renal volume as a surrogate for renal function.

Evaluation of the learning curve for fenestrated endovascular aneurysm repair.

OBJECTIVE: The objective of this study was to evaluate the learning curve for fenestrated endovascular aortic aneurysm repair (FEVAR). METHODS: Data were collected prospectively on all FEVAR procedures conducted by a single surgeon between June 2007 and January 2015. During the study period, 136 FEVARs were performed, and this experience was divided into four quartiles each consisting of 34 cases. Clinical outcomes evaluated included perioperative death and major complications. Process outcomes included length of procedure, fluoroscopy time, contrast material use, estimated blood loss, and intensive care unit length of stay. RESULTS: During the study period, there was a statistically significant increase in the complexity of cases as evidenced by an increase in the proportion of cases with two or more fenestrations from 52.9% in the first quartile to 88.2% in the fourth quartile (P = .001). Despite this, there was a steady decrease in the proportion of patients suffering perioperative death or major complications from 23.5% in the first quartile to 8.8% in the fourth quartile. After adjustment for potential confounding factors, the odds of death or major complication were cut by 52.4% per quartile increase (95% confidence interval [CI], 7.8%-75.5%; P = .028). In addition, among cases with two or more fenestrations, geometric mean length of procedure was reduced from 223.8 minutes in the first quartile to 149.6 minutes in the fourth quartile, and geometric mean fluoroscopy time was reduced from 58.6 minutes in the first quartile to 31.5 minutes in the fourth quartile. After adjustment, there was an estimated 9.9% reduction in geometric mean procedure length per quartile increase (95% CI, 3.5%-15.9%; P = .003) and a 17.6% reduction in geometric mean fluoroscopy time per quartile increase (95% CI, 10.9%-23.8%; P < .0001). CONCLUSIONS: Despite an increase in case complexity, there was evidence for significant improvement in important clinical and process outcomes during the study period. We believe that much of this improvement was attributable to several key advances in the FEVAR procedure that were instituted during the study period and are discussed herein.

Re-entry into the true lumen from the subintimal space.

Endovascular reconstruction of the femoral and popliteal arteries is replacing femoral-popliteal bypass. This is made possible by subintimal recanalization to manage long chronic total occlusions. Re-entry into the true lumen is the most challenging step in this process. This article summarizes the techniques for re-entry into the true lumen in the superficial femoral and above- and below-the-knee popliteal arteries.

Establishing sheath access for carotid interventions: tips and pitfalls.

Carotid angioplasty and stenting requires delivery of therapy through a sheath rather than open vascular access. Safe and successful sheath delivery facilitates the carotid angioplasty and stenting procedure and depends upon an ability to assess the aortic arch, catheterize its branches, perform remote access guidewire-catheter manipulation, and place a sheath.

Relationship of medial arterial calcinosis to autonomic neuropathy and adverse outcomes in a diabetic veteran population.

STATEMENT OF THE PROBLEM: Medial arterial calcinosis (MAC) is associated with neuropathy, amputation, and mortality through an unknown mechanism. We hypothesized that MAC was a marker of autonomic neuropathy rather than a risk factor and that the outcomes were due to autonomic neuropathy. METHODS: All subjects in an ongoing prospective study of diabetic foot conditions in a diabetic veteran cohort who received a foot radiograph between 11/7/90 and 11/5/93 were included. Autonomic neuropathy measured as either heart rate variability with timed respiration or postural hypotension. A logistic model predicted the presence of MAC at baseline and Cox proportional models assessed the relative contribution of autonomic neuropathy and traditional risk factors for the outcomes of ulceration, amputation, and death. RESULTS: MAC was identified in 181 subjects, no MAC in 253 subjects, and 39 were excluded due to disagreement between observers. Both measures of autonomic neuropathy were independent predictors of MAC at baseline, even after adjustment for vibration sensation loss in a logistic model. MAC was associated with an increased risk for ulceration (hazards ratio, HR: 2.1, 95% confidence intervals, CI, 1.4-3.1), amputation (HR 3.3, 95% CI 1.5-7.4), and mortality (HR 1.6, 95% CI 1.1-2.2). The addition of either autonomic measure of neuropathy did not change the MAC HR or significantly improved the fit of the model. CONCLUSIONS: Our hypothesis that the excess mortality, amputation, and ulceration in persons with MAC could be explained by autonomic neuropathy measured as postural hypotension or heart rate variability with measured respiration was not supported.

Infrainguinal vein graft stenosis: cutting balloon angioplasty as the first-line treatment of choice.

OBJECTIVE: The optimal treatment for hemodynamically significant infrainguinal vein bypass graft stenosis is not known. This study compares three options as first choice for the revision of failing infrainguinal vein grafts: cutting balloon angioplasty (CBA), standard percutaneous transluminal balloon angioplasty (PTA), and open surgical revision (OS). METHODS: Infrainguinal vein bypass graft lesions treated in a single institution during a 12-year period were evaluated. Of these, 161 lesions in 124 infrainguinal bypasses (101 patients) were treated with OS (n = 42), PTA (n = 57), or CBA (n = 62). The initial indication for the bypass in these patients was limb salvage in 73% and claudication in 27%. The primary outcome of interest was the development of vein graft occlusion or significant stenosis (>or=70%) as detected by surveillance duplex ultrasound scanning or arteriography some time after repair. RESULTS: The stenosis-free patency rates at 48 months for OS, CBA, and PTA were 74%, 62%, and 34%, respectively. PTA was associated with an increased risk of treatment failure compared with both OS (hazard ratio [HR], 3.9; P < .0001) and CBA (HR, 3.1; P < .0001). There was no significant difference between OS and CBA (HR, 1.3 for CBA vs OS, P = .6). Pseudoaneurysms developed in two CBA patients. One ruptured and required interposition graft, and one was monitored. CONCLUSION: Cutting balloon angioplasty is a reasonable, initial treatment for infrainguinal vein graft stenosis in most patients. It is a safe, minimally invasive, outpatient procedure with patency rates that are comparable to OS and superior to PTA.

Safety and efficacy of carotid arteriography in vascular surgery practice.

OBJECTIVE: Carotid arteriography (CA) is an important method of assessing carotid artery occlusive disease and is the best method of planning for carotid angioplasty and stent placement (CAS). This study compared the results of CA performed by vascular surgeons in a contemporary series against widely recognized interdisciplinary quality standards for this procedure. Although many vascular surgeons perform CA, there is a paucity of data about its safety, efficacy, and compliance with quality standards in vascular practice. The importance of quality CA will likely increase as CAS emerges to assume a broader clinical role. METHOD: Carotid arteriograms performed by seven vascular surgeons at three institutions from September 2000 to May 2004 were reviewed. These results were compared with quality standards for the performance of CA. RESULTS: Five hundred three carotid arteriograms were performed over 45 months. Indications for the procedure were extracranial cerebrovascular disease (86%), trauma (5%), and other conditions (9%). Indications for the procedure were appropriate in 100% of patients (as determined by guidelines document) and exceeded the recommended standard of appropriate indications in 99%. All procedures successfully provided the information required, exceeding the threshold of 98% for procedural success. Reversible neurologic deficits occurred in 0.6% (two transient ischemic attacks and one stroke) compared with the threshold of 2.5%. A permanent neurologic deficit occurred in 0.2% (1 patient) compared with the published guideline of 1% after carotid arteriography. Major non-neurologic complications occurred in 1.2% (6 patients), less than the standard of 2.0%. CONCLUSIONS: The safety and efficacy of a contemporary series of CA performed in vascular surgery practice compared favorably with recognized interdisciplinary quality standards for this procedure. Ensuring safe and effective CA is likely to support the successful growth of CAS as a treatment option.

Deep venous thrombosis and ABO blood group are unrelated in trauma patients.

BACKGROUND: Although epidemiologic studies of the general population have demonstrated a deficit of blood group O among patients with deep venous thrombosis (DVT), few studies have evaluated the importance of blood group in high-risk patients. The purpose of this study was to evaluate the importance of ABO blood group as a thrombotic risk factor in injured patients. METHODS: Injured patients with a discharge diagnosis of DVT were identified from an institutional trauma registry and compared with control patients matched for age and Injury Severity Score. ABO blood types of patients and controls were obtained from the regional blood center database. RESULTS: Three hundred forty-three case-control pairs were identified from a total of 401 consecutive cases of DVT. Blunt injury was the predominant mechanism of injury, accounting for 90.4% of cases. Chest (p = 0.01) and extremity (p < 0.001) Abbreviated Injury Scale scores were independent predictors of DVT. However, there was no significant difference in blood group distribution or the A to O ratio between patients with and without DVT. For non-type O patients, the odds ratio for developing DVT was 1.1 (95% confidence interval, 0.8-1.5; p = 0.5) in comparison with type O patients. CONCLUSION: These data do not support a clinically relevant association between blood type and DVT in trauma patients. Injury-associated derangements of coagulation may be more important than any hypercoagulability related to blood type in this population.

Effect of ethnicity on access and device complications during endovascular aneurysm repair.

INTRODUCTION: There are no published reports on the association between ethnicity and outcome after aortoiliac stent grafting to treat aneurismal disease. Because Hawaii is a state with an ethnically diverse population, we conducted a retrospective study to examine this potential association. We hypothesized that individuals of Asian ancestry may have higher complication rates after endovascular repair compared with non-Asians. METHODS: All endovascular devices placed to treat aneurysm disease from 1996 to 2003 were evaluated in two institutions. The association between ethnicity and access-related and device-related complications, both periprocedural and delayed, was examined with logistic regression analysis. RESULTS: Ninety-two aortoiliac endografts were placed during the study period, including 87 in patients with abdominal aortic aneurysms with or without iliac aneurysm disease, and five patients with isolated iliac artery aneurysms. Forty-four percent of patients were categorized as Asian, 39% as white, 16% as Pacific Islander, and 1% as African American. Access-related and device-related complications (ADRCs) occurred in 11 of 92 (12%) of these patients. The following parameters were significantly associated with ADRCs: Asian ethnicity (P =.015), age greater than 80 years (P =.02), and external iliac diameter smaller than 7.5 mm (P =.01). Asian patients were more likely to have experienced ADRCs than were non-Asian patients (odds ratio, 7.3; 95% confidence interval, 1.5-35.8; P =.015). Asians also had smaller external iliac artery diameters (P =.0003) and more tortuous iliac arteries (P =.03) compared with non-Asians. After adjusting for iliac artery diameter and tortuosity, the association between Asian ethnicity and ARDCs became nonsignificant (P =.074), which suggests that the association between race and complications may be at least in part due to small and tortuous iliac arteries. There was no association between age, gender, or ethnicity and postoperative detection of endoleak. CONCLUSION: Our data indicate that individuals of Asian ancestry are far more likely to experience adverse access-related and device-related complications after aortoiliac stent grafting than are non-Asians. We found that this association is at least partly attributable to the smaller and more tortuous iliac arteries in persons of Asian ancestry.