J. Mark McKinney

Effect of suprarenal versus infrarenal aortic endograft fixation on renal function and renal artery patency: a comparative study with intermediate follow-up ☆

PURPOSE Suprarenal fixation of aortic endografts appears to be a safe option in patients with a short or conical proximal aortic neck. However, concern persists regarding the long-term effect on renal function when renal artery ostia are crossed by the uncovered stent. We investigated the effect of suprarenal versus infrarenal endograft fixation on renal function and renal artery patency after endovascular aortic aneurysm repair. METHODS Records of 91 patients who underwent endovascular aortic aneurysm repair with a modular bifurcated stent graft between November 1999 and January 2002 were reviewed retrospectively. Two patients receiving dialysis because of chronic renal failure were excluded. Infrarenal fixation was used in 57 patients (group 1), and suprarenal fixation was used in 32 patients (group 2). In two patients in group 1 a Gianturco Z stent was inserted transrenally because of intraoperative proximal type I endoleak, and data for these patients were excluded from analysis. Follow-up evaluation was performed at 1, 6, and 12 months, and yearly thereafter, and included clinical assessment, measurement of serum creatinine concentration (SCr), and computed tomography angiography, per standard protocol. Median follow-up was 12 months (range, 1-36 months). RESULTS There was no statistically significant difference in patient demographic data, aneurysm size, or preoperative risk factors. Median SCr was significantly higher in group 2 (suprarenal fixation) than in group 1 (infrarenal fixation) preoperatively (1.2 mg/dL [range, 0.6-2.3 mg/dL] vs 0.9 mg/dL [range, 0.6-1.9 mg/dL], P =.008) and at 1 month postoperatively (1.1 mg/dL [range, 0.8-5.6 mg/dL] vs 1.0 mg/dL [range, 0.6-2.1 mg/dL], P =.045). There was a significant increase in median SCr in both groups at 1 month postoperatively (group 1, 1.0 mg/dL [range, 0.6-2.1 mg/dL], P =.05; group 2, 1.1 mg/dL [range, 0.8-5.6 mg/dL] [mean SCr, 1.35 mg/dL vs 1.15 mg/dL, respectively], P <.05). In group 1 SCr was increased significantly at 6 and 12 months (P <.001), whereas in group 2 SCr also increased at 6 and 12 months, but not significantly. The change in SCr over time was not significantly different between the two groups. In two of 32 patients in group 2, renal artery occlusion developed, associated with perfusion defects in renal parenchyma and persistently elevated SCr. Analysis of renal artery patency did not demonstrate any association between patency and treatment. No patient developed hypertension during follow-up. CONCLUSIONS Suprarenal endograft fixation does not lead to significant renal dysfunction, and renal artery occlusion is uncommon within 12 months. A larger study with longer follow-up is essential to determine overall effects on renal function and renal artery patency.

Caval Penetration by Inferior Vena Cava Filters A Systematic Literature Review of Clinical Significance and Management

Background— Limited penetration into the caval wall is an important securing mechanism for inferior vena cava (IVC) filters; however, caval penetration can also cause unintentional complications. The aim of this study was to assess the incidence, severity, clinical consequences, and management of filter penetration across a range of commercially available IVC filters. Methods and Results— The MEDLINE database was searched for all studies (1970–2014) related to IVC filters. A total of 88 clinical studies and 112 case reports qualified for analysis; these studies included 9002 patients and 15 types of IVC filters. Overall, penetration was reported in 19% of patients (1699 of 9002), and 19% of those penetrations (322 of 1699) showed evidence of organ/structure involvement. Among patients with penetration, 8% were symptomatic, 45% were asymptomatic, and 47% had unknown symptomatology. The most frequently reported symptom was pain (77%, 108 of 140). Major complications were reported in 83 patients (5%). These complications required interventions including surgical removal of the IVC filter (n=63), endovascular stent placement or embolization (n=11), endovascular retrieval of the permanent filter (n=4), and percutaneous nephrostomy or ureteral stent placement (n=3). Complications led to death in 2 patients. A total of 87% of patients (127 of 146) underwent premature filter retrieval or interventions for underlying symptoms or penetration-related complications. Conclusions— Caval penetration is a frequent but clinically underrecognized complication of IVC filter placement. Symptomatic patients accounted for nearly 1/10th of all penetrations; most of these cases had organ/structure involvement. Interventions with endovascular retrieval and surgery were required in most of these symptomatic patients. # CLINICAL PERSPECTIVE {#article-title-44}Background— Limited penetration into the caval wall is an important securing mechanism for inferior vena cava (IVC) filters; however, caval penetration can also cause unintentional complications. The aim of this study was to assess the incidence, severity, clinical consequences, and management of filter penetration across a range of commercially available IVC filters. Methods and Results— The MEDLINE database was searched for all studies (1970–2014) related to IVC filters. A total of 88 clinical studies and 112 case reports qualified for analysis; these studies included 9002 patients and 15 types of IVC filters. Overall, penetration was reported in 19% of patients (1699 of 9002), and 19% of those penetrations (322 of 1699) showed evidence of organ/structure involvement. Among patients with penetration, 8% were symptomatic, 45% were asymptomatic, and 47% had unknown symptomatology. The most frequently reported symptom was pain (77%, 108 of 140). Major complications were reported in 83 patients (5%). These complications required interventions including surgical removal of the IVC filter (n=63), endovascular stent placement or embolization (n=11), endovascular retrieval of the permanent filter (n=4), and percutaneous nephrostomy or ureteral stent placement (n=3). Complications led to death in 2 patients. A total of 87% of patients (127 of 146) underwent premature filter retrieval or interventions for underlying symptoms or penetration-related complications. Conclusions— Caval penetration is a frequent but clinically underrecognized complication of IVC filter placement. Symptomatic patients accounted for nearly 1/10th of all penetrations; most of these cases had organ/structure involvement. Interventions with endovascular retrieval and surgery were required in most of these symptomatic patients.

Femoral incision morbidity following endovascular aortic aneurysm repair

Currently available aortic stent-grafts require bilateral femoral incisions for device deployment. The incidence of morbidity (infection, lymphatic complications, breakdown) of vertical, infrainguinal incisions used in endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAAs) was assessed, and the natural history of asymptomatic groin fluid collections following such procedures was determined. Between June 1999 and February 2001, 77 consecutive patients underwent EVAR for AAAs utilizing bilateral vertical femoral incisions. Fifty-nine (77%) bifurcated stent-grafts (BSGs), and 18 (23%) aortouniiliac (AUI) devices, with femorofemoral bypass were performed. Patients returned at 2 weeks, 1 month, and 6 months for physical examination, and 1 month and 6 months for abdominal and pelvic computed tomography (CT) scans. The presence of fluid collections was determined from the dictation report of the attending radiologist. Data are reported as (n) mean ± SE. Patient characteristics were compared using Fishers exact test; p <0.05 considered significant. There were 72 males and 5 females, age 75 ±6.4 years and aneurysm size (77) 5.6 ±0.8 cm. There were no cases of wound breakdown or lymph fistula. Wound infections occurred in 3/150 incisions (2%), 2/34 AUI incisions (6%), and 1/1 16 BSG incisions (0.86%). There was no statistical difference (p =0.13) between graft types (BSG vs AUI). All infections were diagnosed clinically before the 1-month CT scan, treated without operative intervention or hospitalization, and resolved. There was a significant decrease in the BSG group and overall in asymptomatic wound fluid collections from 1 to 6 months postoperatively. At 1 and 6 months, respectively, the BSG group had 17 (14.6%) and 3 (2.6%) fluid collections out of 116 incisions (p = 0.003); the AUI group had 6 (17.6%) and 1 (2.9%) fluid collection(s) out of 34 incisions (p = 0. 13); and overall 23 (15.3%) and 4 (2.6%) out of 150 incisions (p = 0.004). The present study demonstrates that bilateral vertical femoral incisions used in EVAR have a wound infection rate of 2.0%. Infections are usually detected and treated clinically and empirically without the need for hospitalization or surgery. Asymptomatic groin wound fluid collections resolve significantly within 6 months without intervention. Therefore, surgical femoral artery exposure adds little morbidity to the endovascular repair of abdominal aortic aneurysms.

Natural History of the Iliac Arteries after Endovascular Abdominal Aortic Aneurysm Repair and Suitability of Ectatic Iliac Arteries as a Distal Sealing Zone

PURPOSE To investigate the natural history of dilated common iliac arteries (CIA) exposed to pulsatile blood flow after endovascular abdominal aortic aneurysm repair (EVAR) and the suitability of ectatic iliac arteries as sealing zones using flared iliac limbs. METHODS Follow-up computed tomograms of 102 CIAs in 60 EVAR patients were investigated. Diameter changes in CIAs < or =16 mm (group 1) were compared with changes in vessels where a dilated segment >16 mm in diameter continued to be exposed to pulsatile blood flow (group 2). Within group 2, cases in which the stent terminated proximal to the dilated artery segment (2a) were compared with those that had been treated with a flared limb (2b). RESULTS The mean CIA diameter increased by 1.0+/-1.0 mm in group 1 (p<0.001 versus immediately after EVAR) and by 1.5+/-1.7 mm in group 2 (p<0.001 versus immediately after EVAR) within an average follow-up of 43.6+/-18.0 months. Diameter increase was more pronounced in dilated CIAs (p=0.048), and it was not significantly different between groups 2a and 2b (p=0.188). No late distal type I endoleak or stent-graft migration associated with CIA ectasia was observed. CONCLUSION Dilatation of the CIA is significant after EVAR, and it is more pronounced in ectatic iliac arteries. Although ectatic iliac arteries appear to be suitable sealing zones in the short term, continued follow-up is mandatory.

Radioembolization and the dynamic role of 90Y PET/CT

Before the advent of tomographic imaging, it was postulated that decay of 90 Y to the 0+ excited state of 90Zr may result in emission of a positron–electron pair. While the branching ratio for pair-production is small (~32 × 10−6), PET has been successfully used to image 90 Y in numerous recent patients and phantom studies. 90 Y PET imaging has been performed on a variety of PET/CT systems, with and without time-of-flight (TOF) and/or resolution recovery capabilities as well as on both bismuth-germanate and lutetium yttrium orthosilicate (LYSO)-based scanners. On all systems, resolution and contrast superior to bremsstrahlung SPECT has been reported. The intrinsic radioactivity present in LYSO-based PET scanners is a potential limitation associated with accurate quantification of 90 Y. However, intrinsic radioactivity has been shown to have a negligible effect at the high activity concentrations common in 90 Y radioembolization. Accurate quantification is possible on a variety of PET scanner models, with or without TOF, although TOF improves accuracy at lower activity concentrations. Quantitative 90 Y PET images can be transformed into 3-dimensional (3D) maps of absorbed dose based on the premise that the 90 Y activity distribution does not change after infusion. This transformation has been accomplished in several ways, although the most common is with the use of 3D dose-point-kernel convolution. From a clinical standpoint, 90 Y PET provides a superior post-infusion evaluation of treatment technical success owing to its improved resolution. Absorbed dose maps generated from quantitative PET data can be used to predict treatment efficacy and manage patient follow-up. For patients who receive multiple treatments, this information can also be used to provide patient-specific treatment-planning for successive therapies, potentially improving response. The broad utilization of 90 Y PET has the potential to provide a wealth of dose–response information, which may lead to development of improved radioembolization treatment-planning models in the future.

Impact of gender on the outcome of endovascular aortic aneurysm repair using the Zenith stent-graft: midterm results.

PURPOSE To analyze the 2-year outcomes of female patients after endovascular aortic aneurysm repair (EVAR) with the Zenith AAA Endovascular Graft. METHODS A retrospective analysis was conducted of data from the US Zenith multicenter trial and the Zenith female registry on 40 women (10.9%, study group) and 326 men (89.1%, control group) enrolled. All patients had completed their 2-year follow-up. Primary study endpoints were survival, aneurysm rupture, and conversion rate. Significance was assumed if p<0.05. RESULTS Overall rates of mortality (12.5% for women versus 13.2% for men, p = 0.94) and aneurysm rupture (2.5% for women versus 0% for men, p = 0.11) were comparable between groups. Conversion to open repair within 2 years was significantly more frequent in women compared to men (7.5% versus 0.6%, p = 0.01). The incidence of endoleaks of any type was equivalent between groups at 2 years (13.3% for women versus 6.9% for men, p = 0.30). No difference was observed in the need for secondary interventions (15% for women versus 13.5% for men, p = 0.81) or aneurysm dilatation >5 mm (10.5% for women versus 2.3% for men, p = 0.10). None of the patients developed device migration >10 mm or required intervention for migration. CONCLUSION While women underwent conversion to open repair more frequently compared to men at 2 years post EVAR, there was no difference in survival, freedom from aneurysm rupture, or need for secondary interventions between groups. As in men, the Zenith AAA Endovascular Graft provides reliable protection from aneurysm rupture and aneurysm-related death in women in a midterm follow-up.

Management of a Large Intraoperative Type IIIb Endoleak in a Bifurcated Endograft A Case Report

The purpose of this paper is to describe the intraoperative management of a type IIIb endoleak after deployment of a bifurcated endograft in a patient with narrow iliac access vessels. A 62-year-old man underwent elective endovascular repair (EVAR) of a 53 mm abdominal aortic aneurysm. After device deployment, a large IIIb endoleak, arising from the main body of the device, was visualized. Narrow iliac vessels precluded deployment of a second bifurcated graft, and the endoleak was successfully excluded with an aortomonoiliac device, followed by contralateral iliac occlusion and subsequent creation of a femorofemoral bypass. At 1-year follow-up, the aneurysm remains excluded and is decreasing in size. Type III endoleaks are a known complication of EVAR, requiring immediate treatment through their association with aneurysm enlargement and rupture. If an additional bifurcated graft cannot be used, aortomonoiliac conversion represents a feasible endovascular alternative treatment for type III endoleaks, other than conversion to open surgical repair. Therefore, aortomonoiliac converters with appropriate occluder devices should be readily available during deployment of bifurcated devices.

Does chronic oral anticoagulation with warfarin affect durability of endovascular aortic aneurysm exclusion in a midterm follow-up?

Purpose: To evaluate the effect of oral anticoagulation on durability of endovascular aortic aneurysm repair (EVAR). Methods: Retrospective review was conducted of 182 consecutive EVAR patients (169 men; mean age 75.3 years, range 53–89) between 1999 and 2003. Patients on warfarin anticoagulation (WA, n=21; International Normalized Ratio of 2 to 3) were compared against a control group (CG) with no postoperative anticoagulation (n=161). Death, aneurysm rupture, and reintervention were considered primary endpoints; endoleaks, endograft migration, and aneurysm remodeling were secondary endpoints. Results: Mean follow-up was 16.3±12.6 months. One-year mortality was 6.6% (9.5% WA versus 6.2% CG); overall mortality was 14.3% (p=0.414). No aneurysm rupture occurred. At 1, 2, and 3 years, respectively, cumulative reinterventions (20%/20%/20% WA versus 12%/15%/20% CG; p=0.633) and endoleak rates (25%/25%/25% WA versus 17%/22%/34% CG; p=0.649) were comparable. In both groups, most completion endoleaks resolved (42.9% WA versus 74.4% CG; p=0.474), but few de novo endoleaks did (0% WA versus 12.8% CG; p=0.538). Anticoagulation did not affect mean time to aneurysm sac shrinkage (1.3±0.3 WA versus 1.4±0.1 years CG; p=0.769). Conclusions: After EVAR, anticoagulation appears safe and does not significantly alter mortality, risk for rupture, or the incidence of reintervention. Early endoleaks appear more common in anticoagulated patients, but anticoagulation does not preclude spontaneous endoleak resolution nor does it increase late endoleak rates. Irrespective of the anticoagulation status, early but not late endoleaks usually sealed spontaneously. Observing type II endoleaks appears safe in the absence of aneurysm enlargement.

Single-institution experience of radioembolization with yttrium-90 microspheres for unresectable metastatic neuroendocrine liver tumors: Y-90 treat liver neuroendocrine tumor

The aim of this study was to assess the effectiveness of yttrium‐90 (90Y) microspheres for the treatment of unresectable metastatic liver neuroendocrine tumors (NET).

Percutaneous Protective Coil Occlusion of the Proximal Inferior Mesenteric Artery before N-Butyl Cyanoacrylate Embolization of Type II Endoleaks after Endovascular Repair of Abdominal Aortic Aneurysms

Bowel ischemia can complicate treatment of type II endoleak with liquid or semiliquid agents such as n-butyl cyanoacrylate (NBCA) if nontarget embolization of the inferior mesenteric artery (IMA) occurs. The current report describes four cases of type II endoleak in which the IMA was the main outflow vessel and was prophylactically occluded with embolization coils before NBCA injection into the endoleak nidus. The purpose was to prevent unintentional embolization of the NBCA into IMA branches. If feasible, protective IMA coil occlusion should be considered in type II endoleaks with IMA outflow in cases of NBCA embolization.