Ellen D. Dillavou

Five-year results of endovascular treatment with the Gore TAG device compared with open repair of thoracic aortic aneurysms

OBJECTIVES Report the results of a phase II multicenter, prospective trial comparing endovascular treatment of descending thoracic aneurysm (TEVAR) with the TAG device to surgical controls after 5 years of follow-up. METHODS The Gore TAG trial compared the TAG endograft patients (n = 140) with standard open surgical controls (n = 94) with enrollment from September of 1999 to May of 2001. An additional 51 patients were enrolled in 2003 after revision of the endograft. Follow-up consisted of patient visits, computed tomography (CT) scans and x-rays at 1, 6, and 12 months and yearly. Significant sac size change was defined as >or=5 mm increase or decrease from the 1 month baseline measurement. Migration was defined as >or=10 mm cranial or caudal movement of the device inside the aorta. Significance was determined as P <or= .05. RESULTS At 5 years, aneurysm-related mortality was lower for TAG patients at 2.8% compared with open controls at 11.7% (P = .008). No differences in all-cause mortality were noted, with 68% of TAG patients and 67% of open controls surviving to 5 years (P = .43). Major adverse events at 5 years were significantly reduced in the TAG group; 57.9% vs 78.7% (P = .001). Endoleaks in the TAG group decreased from 8.1% at 1 month to 4.3% at 5 years. Five TAG patients have undergone major aneurysm-related re-interventions at 5 years (3.6%), including one arch aneurysm repair for type 1 endoleak and migration, one open conversion and five endovascular procedures for endoleaks in three patients. There were fewer secondary procedures not directly related to aneurysm repair in the TAG vs the open repair group at 5 years, 15.0% vs 31.9%, (P = .01). For TAG patients, sac size at 60 months decreased in 50% and increased in 19% compared with the 1-month baseline. Comparison with the modified low-porosity device at 24 months showed sac increase in 12.9% of original vs 2.9% in modified grafts (P = .11). At 5 years, there have been no ruptures, one migration, no collapse, and 20 instances of fracture in 19 patients, all before the revision of the TAG graft. CONCLUSIONS In anatomically suitable patients, TAG treatment of thoracic aneurysms is superior to surgical repair at 5 years. Although sac enlargement is concerning, early modified device results indicate this issue may be resolved.

Does hostile neck anatomy preclude successful endovascular aortic aneurysm repair

OBJECTIVES Poor outcomes have been reported with endovascular aneurysm repair (EVAR) in patients with hostile neck anatomy. Unsupported endografts with active fixation may offer certain advantages in this situation. We compared EVAR results using the Ancure (Guidant) endograft in patients with and without hostile neck anatomy. METHODS Records of EVAR patients from October 1999 to July 2002 at a tertiary care hospital were retrospectively reviewed from a division database. Patients with elective open abdominal aortic aneurysm (AAA) repair during the same period were reviewed to determine those unsuitable for EVAR. Hostile neck anatomy, assessed by computer tomography (CT) scans and angiograms, was defined as one or more of the following: (1) neck length </=10 mm, (2) focal bulge in the neck >3 mm, (3) >2-mm reverse taper within 1 cm below the renal arteries, (4) neck thrombus > or =50% of circumference, and (5) angulation > or =60 degrees within 3 cm below renals. RESULTS Three hundred and twenty-two patients underwent EVAR with an average follow-up of 18 months. Patients in Phase II trials (n = 41), repaired with other graft types (n = 48), or without complete anatomic records (n = 27) were excluded. Demographics and co-morbidities were similar in the 115 good-neck (GN) and 91 bad-neck (BN) patients except for age (mean, 72.9 years GN vs 75.7 BN; P = 0.13), gender (11% female GN vs 22% BN; P =.04); neck length (mean, 21.8 mm GN vs 14.4 mm BN: P <.001), and angulation (mean, 22 degrees GN vs 40 degrees BN; (P <.001). Perioperative mortality (0 GN vs 1.1% BN), late mortality (5.2% GN vs 4.4% BN), all endoleaks (19.1% GN vs 17.6% BN), proximal endoleaks (0.8% GN vs 2.1% BN), and graft migration (0 for both groups) did not reach statistical significance. Neck anatomy precluded EVAR in 106 of 165 (64%) patients with open AAA. CONCLUSIONS Unsupported endografts with active fixation can yield excellent results in treating many medically compromised patients with hostile neck anatomy. Nonetheless, an unsuitable neck remains the most frequent cause for open abdominal AAA.

A randomized trial of carotid artery stenting with and without cerebral protection

BACKGROUND The use of a distal filter cerebral protection device with carotid artery stenting is commonplace. There is little evidence, however, that filters are effective in preventing embolic lesions. This study examined the incidence of embolic phenomenon during carotid artery stenting with and without filter use. METHODS This was a prospective, randomized, single-center study of carotid artery stenting with or without a distal cerebral protection filter. A 1:1 scheme was used to randomize 36 carotid artery stenting procedures in 35 patients. Diffusion-weighted magnetic resonance imaging (DW MRI) 24 hours after stenting was used to assess the occurrence of new embolic lesions. Blinded observers calculated lesion number and volume. RESULTS The mean age was 78.6 +/- 7.0 in the cerebral protection group compared with 74.1 +/- 8.7 in the no cerebral protection group (P = .92). Despite similar average age, the percentage of octogenarians was higher in the cerebral protection group (61.1% vs 22.2%; P = .04). Two procedures in the cerebral protection group were not successful. One was completed without protection because of inability to track the filter, and the second was aborted because of severe tortuosity with a later carotid endarterectomy. New MRI lesions were noted in 72% of the cerebral protection group compared with 44% in the no cerebral protection group (P = .09). The average number of lesions in these patients was 6.1 and 6.2, respectively, with mean DW MRI lesion size of 16.63 mm(3) vs 15.61 mm(3) (P = .79 and .49, respectively). Four strokes occurred (11%), two in each group, in patients aged 75, 80, 82, and 84 years. The only major stroke occurred in the no cerebral protection group. CONCLUSIONS The use of filters during carotid artery stenting provided no demonstrable reduction of microemboli, as expected. Routine use of cerebral protection filters should undergo a more critical assessment before mandatory universal adoption.

Treatment strategies of arterial steal after arteriovenous access

INTRODUCTION Ischemic steal syndrome (ISS) associated with arteriovenous (AV) access is rare but can result in severe complications. Multiple techniques have been described to treat ISS with varying degrees of success. This study compares the management and success associated with these techniques. METHODS Patients with ISS between June 2003 and June of 2008 at the University of Pittsburgh Medical Center were retrospectively reviewed. Demographics, type of AV access, management technique, and success of intervention were recorded. Success was defined as resolution of ISS symptoms while preserving access function. One hundred consecutive AV access procedures were reviewed for comparison. Data were analyzed using χ(2) test, Fishers exact test, and Students t test. The study was approved by our institutional review board. RESULTS A total of 114 patients with ISS had a mean age of 65 years (range, 20-90 years), were predominantly female (66%), diabetic (61%), and with a brachial origin fistula (69%). Risk factors for ISS included coronary artery disease (CAD; P < .001), hypertension (P < .001), and tobacco use (P = .048). Women were noted to have a brachial origin access more frequently than men (odds ratio [OR], 3.1; P = .009). Forty-four patients with mild steal were observed. Seventy patients underwent 87 procedures. Procedures performed included ligation (n = 27), banding (n = 22), distal revascularization and interval ligation (DRIL; n = 21), improvement of proximal inflow (n = 9), revision using distal inflow (RUDI; n = 4), and proximalization of arterial inflow (PAI; n = 3). Early procedures (<30 days from the index fistula) were mostly ligation (50%) or banding (38%), while DRIL was the most frequent choice for late interventions (41%). Banding had a high failure rate (62%) and was the most common reason for reintervention (8 of 11, 73%) and DRIL had a better success rate than banding (P ≤ .05). In our current practice, 18% of patients had an AV fistula with the proximal radial artery (PRA) as the inflow source, while this type of fistula accounted for only 2% of all ISS patients. Ligation resolved symptoms in all patients, but the AV access was lost. CONCLUSIONS Risk factors for development of ISS include CAD, diabetes, female gender, hypertension, and tobacco use. Among various options to treat ISS, banding has a low success rate and high likelihood for reintervention, while DRIL is particularly effective although not uniformly. Less invasive treatment options such as RUDI and PAI may be quite effective in treating ISS. Use of the PRA as the inflow source may decrease the incidence of ISS.

Lower extremity iatrogenic nerve injury due to compression during intraabdominal surgery

BACKGROUND latrogenic nerve injury due to poor positioning and external compression is a common surgical complication. However, sciatic neuropathy from external compression and femoral nerve injury after self-retaining retraction are less-published complications. METHODS Surgical Morbidity and Mortality Reports from 1986 through 1995 were reviewed to identify femoral and sciatic neuropathies following intraabdominal vascular and general surgeries. RESULTS Two sciatic and 5 femoral neuropathies were reported, an incidence of approximately 0.17% of abdominal cases. Sciatic injuries were attributed to external compression, whereas femoral neuropathies were due to compression by self-retaining retraction. The 3 female and 4 male patients had a mean age of 53.4 years, and no patient had a prior history of peripheral neuropathy. Mean operating time for sciatic injuries was 8.2 hours, versus 4.3 hours for femoral neuropathies. Both patients with sciatic neuropathy had complete resolution of symptoms, compared with 1 femoral neuropathy patient. Two femoral neuropathies were permanent, 1 had partial resolution and 1 had improvement at 4 months but was lost to follow-up. CONCLUSIONS Sciatic and femoral compression neuropathies are rare but serious complications of abdominal surgery. When retracting in the deep pelvis, consideration should be given to using small, well-padded retractor blades and repositioning these regularly. Prevention of sciatic nerve compression requires careful padding of the table surface, especially for longer cases.

Institutional protocol improves retrievable inferior vena cava filter recovery rate

BACKGROUND In the trauma population, the use of retrievable inferior vena cava filters (RIVCF) is rapidly gaining acceptance in patients at high risk for venous thromboembolism. This study reports the impact of an institutional protocol on retrieval rates of RIVCF at a level I trauma center. METHODS A review of an institutional Trauma Registry identified 94 consecutive patients who received RIVCF between January 2004 and February 2007 (group I) before the protocol was instituted. Under the protocol, 61 consecutive trauma patients received RIVCF between August 2007 and July 2008 (group II) and were prospectively followed. RESULTS Filter retrieval eligibility criteria were met in 81% (76/94) of patients in group I and in 61% (37/61) of patients in group II. Of those eligible, retrieval-attempt rates were 42% (32/76) in group I versus 95% (35/37) in group II (P < .001). Clinician oversight of the filter accounted for 89% (39/44) of failure of retrieval attempts; patient noncompliance accounted for the rest in group I. In group II, the latter accounted for all such failures. Retrieval was successful in 37% (28/76) and in 84% (31/37) of the eligible patients in groups I and II, respectively (P < .001). No retrieval procedure-related complications occurred. CONCLUSION An institutional protocol for prospective monitoring of RIVCF significantly increases filter retrieval rate.

Gender-related differences in the tensile strength of abdominal aortic aneurysm

Abstract:  A recent study investigated the association of gender with the growth rate of AAAs and found a significant increase in the growth rate of AAAs in women than in men. On the basis of these observations, we hypothesize that there are gender‐associated differences in AAA wall integrity and mechanical strength. The purpose of this study was to explore this hypothesis by comparing the tensile strength of freshly resected AAA tissue specimens between women and men. Seventy‐six rectangular specimens (20 mm long × 5 mm wide) from 34 patients (24 male, 10 female) were excised from the anterior wall of patients undergoing open repair of their abdominal aortic aneurysm and tested in a uniaxial tensile tester. Ultimate tensile strength (UTS) was taken as the peak stress obtained before specimen failure. While there were no statistical differences in strength between specimens taken from male and female patients, there was a trend toward a decrease in strength in females as compared to males (87.6 ± 6.7 N/cm2 vs. 67.6 ± 8.1 N/cm2, p = 0.09). To the authors knowledge this work represents the first report of differences in biomechanical properties as a function of gender. The nearly significant decrease in UTS in women versus men reported here may be important in assessing the risk of rupture in AAA. Further testing is warranted to confirm the current trends.

Report on the Hemodialysis Reliable Outflow (HeRO) experience in dialysis patients with central venous occlusions

OBJECTIVE The Hemodialysis Reliable Outflow (HeRO) graft (Hemosphere/CryoLife Inc, Eden Prairie, Minn) has provided an innovative means to obtain hemodialysis access for patients with severe central venous occlusive disease. The outcomes of this novel treatment modality in a difficult population have yet to be clearly established. METHODS A retrospective review of HeRO graft placement from June 2010 to January 2012 was performed. Patient hemodialysis access history, clinical complexity, complications, and outcomes were analyzed. Categoric data were described with counts and proportions, and continuous data with means, ranges and, when appropriate, standard deviations. Patency rates were analyzed using life-table analysis, and patency rate comparisons were made with a two-group proportion comparison calculator. RESULTS HeRO graft placement was attempted 21 times in 19 patients (52% women), with 18 of 21 (86%) placed successfully. All but one was placed in the upper extremity. Mean follow-up after successful placement has been 7 months (range, 0-23 months). The primary indication for all HeRO graft placements except one was central vein occlusion(s) and need for arteriovenous access. Patients averaged 2.0 previous (failed) accesses and multiple catheters. Four HeRO grafts (24%), all in women, required ligation and removal for severe steal symptoms in the immediate postoperative period (P < .01 vs men). Three HeROs were placed above fistulas for rescue. All thrombosed <4 months, although the fistulas remained open. An infection rate of 0.5 bacteremic events per 1000 HeRO-days was observed. At a mean follow-up of 7 months, primary patency was 28% and secondary patency was 44%. The observed 12-month primary and secondary patency rates were 11% and 32%, respectively. Secondary patency was maintained in four patients for a mean duration of 10 months (range, 6-18 months), with an average of 4.0 ± 2.2 thrombectomies per catheter. CONCLUSIONS HeRO graft placement, when used as a last-resort measure, has been able to provide upper extremity access in patients who otherwise would not have this option. There is a high complication rate, however, including a very high incidence of steal in women. HeRO grafts should continue to be used as a last resort.

Minimally invasive parathyroidectomy: 101 consecutive cases from a single surgeon

BACKGROUND Intraoperative rapid parathyroid hormone (iPTH) assay is changing parathyroid surgery. One surgeons experience at a tertiary care hospital was followed as minimally invasive parathyroidectomy (MIP) was adopted. STUDY DESIGN In this prospective case study, patients underwent technitium 99m sestamibi scanning, iPTH monitoring, and MIP. A sestamibi-directed incision was made, and iPTH was measured preincision, preexcision of abnormal gland(s), and at 5- and 10-minute intervals. MIP was complete after gland(s) was excised and iPTH fell to less than 50% of preoperative levels. Routine discharge was on the day of surgery with daily calcium and calcitriol to minimize outpatient hypocalcemia. Secondary and tertiary hyperparathyroidism patients were excluded. RESULTS From December 1999 to June 2002, 101 patients underwent MIP. Patients were 27% men and 73% women, with two reoperations. Preoperation laboratory results averaged serum calcium 11.08 (normal 8.5 to 10.5 mg/dL) and parathyroid hormone (PTH) 169 pg/mL (normal 10 to 55 pg/mL). Average iPTH values at operative intervals were 152, 151, 68, and 50 pg/mL, respectively. Operation demonstrated 12% of patients had four-gland hyperplasia, 3% had double adenomas, 2% had parathyroid carcinomas, and 83% had single adenomas. Discharge on the day of surgery occurred in 83% of single-adenoma patients. Postoperative laboratory results averaged calcium 9.4 mg/dL (p < 0.001 versus preoperation) and PTH 48 pg/mL (p < 0.001). Fifteen patients (16%) had elevated PTH after operation, but without elevated calcium levels. One patient had persistant hyperparathyroidism. CONCLUSIONS MIP with iPTH monitoring is a safe and effective means of treating hyperparathyroidism. This approach allows for limited dissection and early discharge for the majority of patients.

Two-Dimensional versus Three-Dimensional CT Scan for Aortic Measurement

Purpose: To examine if 3-dimensional (3D) reconstructions of computed tomographic (CT) data, by imaging perpendicular to blood flow, can improve aortic diameter measurement accuracy over axial (2D) CT. Methods: Two independent, blinded observers used electronic calipers to measure the minor axis and the line perpendicular to it on 40 2.5-mm 2D CT scans from 31 patients. A circular electronic tool was used to estimate diameters on 3D reconstructions from the same 40 scans. Measurements of the aortic neck were obtained 5 mm below the renal arteries and the widest slice of the aneurysm was used to measure sac diameter. Only the minor axis was measured at the iliac arteries immediately above the left (LI) and right (RI) iliac bifurcations. Datasets were compared with an intraclass correlation coefficient (ICC), Bland and Altman variation assessments, and absolute differences. Results: ICC between 2D and 3D scans demonstrated high correlation with 2D minor axis measurements (neck=0.9282, sac=0.8956, RI=0.8755, LI=0.7381). 3D to 2D major axis correlation was lower (neck=0.6388, sac=0.8995). Variation between 3D and 2D minor axis measurements was low (0.51-mm average variation from the mean for the minor axis and 1.30-mm variation for the major axis). Average absolute difference between 3D and 2D diameters was 1.01 mm (minor axis) versus 2.61 mm (major axis). Interobserver correlation was highest for sac measurements both in 2D minor axis (ICC=0.8990) and 3D (ICC=0.9518). Conclusions: Minor axis measurements on axial CT scan can substitute for diameters obtained from 3D reconstructions in most clinical situations.