Management of Endoleaks following Endovascular Aneurysm Repair

Endovascular aneurysm repair (EVAR) has emerged as a viable alternative to open repair for abdominal aortic aneurysms. Endoleaks are a complication unique to EVAR and can occur in up to 25% of patients. In this article, the management of endoleaks following EVAR will be discussed.

Use of antiplatelet inhibitors in peripheral vascular interventions

In the past decade, a tremendous amount of information has been gathered about platelet function and its impact on percutaneous vascular interventions. Strategies for prevention of platelet aggregation have moved beyond aspirin administration. Powerful oral antiplatelet agents such as ticlopidine (Ticlid) and clopidogrel (Plavix) have been developed to prevent platelet aggregation and thrombosis. The discovery of the glycoprotein IIb/IIIa receptor, which is responsible for platelet aggregation, has led to the development of receptor antagonists. These drugs include abciximab (ReoPro), eptifibatide (Integrilin), and tirofiban (Aggrastat). Several large studies have demonstrated that these drugs can improve outcomes in coronary interventions. Because most of the data regarding antiplatelet agents in percutaneous interventions comes from studies of coronary interventions, knowledge of these studies is necessary before using the antiplatelet drugs in peripheral vascular interventions. This article reviews the use of these agents in percutaneous coronary artery interventions and discusses their potential use in peripheral interventions.

Management of transplant renal artery stenosis

Transplant renal artery stenosis is the most frequent vascular complication of transplantation. Early detection and correction reduce patients' morbidity and allograft dysfunction. Although noninvasive imaging can detect an underlying stenosis, angiography with subsequent angioplasty or stenting, or both, provides definitive diagnosis and treatment. With the introduction of alternative contrast agents and newer catheter and stent technology, these procedures can be performed safely with little risk of contrast-induced nephropathy or allograft loss.

Treatment of complications following endovascular repair of abdominal aortic aneurysms

Endovascular aneurysm repair (EVAR) is an important treatment option for abdominal aortic aneurysms, with lower perioperative morbidity and mortality rates than open surgical aneurysm repair. However, EVAR is associated with several unique complications that are not encountered with surgical repair such as endoleaks, graft migration, and renal artery occlusion. Preservation of the morbidity and mortality advantages of EVAR relies on the successful treatment of these complications by minimally invasive, endovascular approaches. Some of the techniques used to treat EVAR complications include balloon dilation and stenting, deployment of additional stent-graft pieces, coil embolization, and thrombolysis. Although the employment of these endovascular salvage techniques is common, data regarding their intermediate- to long-term efficacy is sparse, and further studies are needed to determine their efficacy in preventing conversion to open aneurysm repair and aneurysm rupture.

Retrieval of a wall-embedded recovery inferior vena cava filter using rigid bronchoscopy forceps

Optional inferior vena cava (IVC) filters are an attractive option to help prevent pulmonary embolism because these filters can be retrieved when the risk for thromboembolic events has passed. Retrieval of IVC filters can be difficult if the filter tilts and its tip becomes embedded into the wall of the IVC. A case is presented in which rigid bronchoscopy forceps were used to retrieve a filter that had become embedded in the wall of the IVC.

Imaging Surveillance following Endovascular Aneurysm Repair

Endoleaks are unique complications of endovascular aneurysm repair (EVAR) that necessitate lifelong imaging surveillance for the patient. Several imaging modalities may be used to monitor the patient for endoleaks and other complications related to the stent graft. At present, computed tomographic angiography remains the gold standard for the detection of endoleaks. Other modalities that can be used to detect endoleaks include magnetic resonance, ultrasonography, nuclear medicine techniques, and pressure monitoring. In addition, follow-up imaging with digital subtraction angiography is important for endoleak classification and to guide decisions regarding therapy. In this article, we review the classification of endoleaks and discuss the different imaging strategies available for post-EVAR surveillance.

Embolization of a Recurrent Type 2 Endoleak Using the Liquid Embolic n-Butyl Cyanoacrylate

Endovascular aneurysm repair (EVAR) has become an accepted alternative to open aortic aneurysm repair. Endoleaks are one of the most common complications of EVAR and can result in aneurysm enlargement and rupture. When embolization of type 2 endoleaks is needed, a transarterial or translumbar approach may be used. Metal coils are often utilized, but liquid agents have also been used for embolization. This case report involves endoleak embolization using metallic coils along with the liquid embolic agent n-butyl cyanoacrylate (n-BCA).

Chemoembolization of colorectal liver metastases with cisplatin, doxorubicin, mitomycin C, ethiodol, and polyvinyl alcohol

BACKGROUND

Unresectable colorectal liver metastases have a 1- and 2-year survival of 55% and 33% with current systemic therapies. The authors evaluated response and survival after transarterial chemoembolization.

METHODS

Chemoembolization with cisplatin, doxorubicin, mitomycin C, ethiodized oil, and polyvinyl alcohol particles was performed at monthly intervals for 1 to 4 sessions. Cross-sectional imaging and clinical and laboratory evaluation were performed before treatment, 1 month after treatment, and then every 3 months. A second cycle was performed for intrahepatic recurrence. Toxicity was assessed using National Cancer Institute's Common Toxicity Criteria version 3.0. Response was evaluated using Response Evaluation Criteria in Solid Tumors criteria. Progression and survival were estimated with Kaplan-Meier analysis.

RESULTS

A total of 245 treatments were performed over 141 cycles on 121 patients. Ninety-five of 141 treatment cycles were evaluable for response: 2 (2%) partial response, 39 (41%) stable disease, and 54 (57%) progression. Median time to disease progression (TTP) in the treated liver was 5 months, and median TTP anywhere was 3 months. Median survival was 33 months from diagnosis of the primary colon cancer, 27 months from development of liver metastases, and 9 months from chemoembolization. Survival was significantly better when chemoembolization was performed after first- or second-line systemic therapy (11-12 months) than after third- to fifth-line therapies (6 months) (P = .03). Presence of extrahepatic metastases did not adversely affect survival (P = .48).

CONCLUSIONS

Chemoembolization provided local disease control of hepatic metastases after 43% of treatment cycles. Median survival was 27 months overall, and 11 months when initiated for salvage after failure of second-line systemic therapy.

Triple-lumen peripherally inserted central catheter in patients in the critical care unit: prospective evaluation

PURPOSE

To prospectively evaluate outcomes associated with use of a triple-lumen (TL) peripherally inserted central catheter (PICC) in the intensive care unit (ICU) setting.

MATERIALS AND METHODS

Patients were prospectively enrolled in this HIPAA-compliant, institutional review board-approved study. Informed consent was obtained. All patients were in one hospital's ICUs and needed intermediate-term central venous access requiring three lumina. A 6-F tapered TL PICC was placed by a bedside nursing-based team with backup from the Interventional Radiology department. Placement complications, as well as long-term complications, were recorded. At catheter removal, ultrasonography (US) of the veins containing the TL PICC was performed to detect occult venous thrombosis. Regardless of indication for removal, catheters were sent for culture to detect colonization.

RESULTS

The study was stopped prematurely after 50 of a planned 167 patients were enrolled when a scheduled interim analysis detected a venous thrombosis rate that was considered unacceptably high by the study oversight committee (thrombosis was symptomatic in 20% of patients [10 of 50]). Venous thrombosis (symptomatic or asymptomatic) was detected in 26 of 45 patients (58%; 95% confidence interval [CI]: 43%, 72%) examined with US. Documented catheter-related bloodstream infection did not occur (0%; 95% CI: 0%, 7%); colonization was detected in three of 29 catheter tips sent for culture (10%; 95% CI: 2%, 27%). Catheter malfunction and dislodgment occurred in one patient each.

CONCLUSION

The TL PICC design used in this study resulted in unacceptably high venous thrombosis rates. Even when used in a high-risk setting for infection (ie, the ICU), rates of clinically evident infection and colonization were absent and low, respectively.

Drainage of collections associated with hernia mesh: is it worthwhile?

PURPOSE

Synthetic mesh has revolutionized abdominal wall hernia repair. However, mesh infections present a clinical problem because the standard practice of surgical excision is fraught with increased morbidity. Here, single-institutional outcomes in managing mesh-related collections via percutaneous drainage are retrospectively reviewed to assess its effectiveness.

MATERIALS AND METHODS

A total of 21 patients underwent drainage of perimesh collections. Three types of mesh were employed: polytetrafluoroethylene (PTFE; n = 5), polypropylene (n = 14), and porcine dermal collagen (n = 3). One patient received both polypropylene and PTFE. Drainage was performed with ultrasound guidance (n = 19) or surgical drain exchange (n = 2). Mesh type, culture results, fluid collection size, and location were analyzed with respect to need for mesh excision.

RESULTS

Sixteen of 21 patients (76%) were successfully treated with drainage. One required additional surgical capsulectomy; the mesh was salvaged. Four required mesh excision because of recurrent infection (n = 2) or lack of improvement of clinical course (n = 2). Recurrent infection occurred in six patients, with mesh salvage via conservative management or new drainage in four. Fluid cultures were positive in 68% of patients (n = 13), with Staphylococcus aureus the most common organism. Cultures did not predict mesh excision (P = .26). The PTFE excision rate trended higher compared with polypropylene (40% vs 14%; P = .27). No porcine dermal collagen mesh was excised. Neither fluid collection size nor location predicted mesh excision. Mean follow-up was 319 days (range, 6-1,406 d).

CONCLUSIONS

Percutaneous drainage of suspected mesh-related abscess is effective. The use of PTFE mesh trended toward a higher excision rate.

Embolization of giant renal angiomyolipomas: technique and results

PURPOSE

To evaluate the efficacy and safety of prophylactic embolization of angiomyolipomas (AMLs) larger than 10 cm.

MATERIALS AND METHODS

Sixteen patients (mean age, 41.2 years; 14 women and two men) underwent embolization for 23 AMLs larger than 10 cm. All lesions were embolized by using microcatheters with ethanol and ethiodized oil mixed to a ratio of 7(ethanol) to 3(ethiodized oil). Data collected included pre- and posttreatment AML size, creatinine level, technical success, volume of embolic material used, clinical success, and complications.

RESULTS

The mean AML size before treatment was 15 cm (range, 10-25 cm). Ten of the 16 patients (62%) had all their AMLs treated in one session, whereas six (38%) required multiple sessions. A mean volume of 8.6 mL of the ethanol-ethiodized oil mixture (range, 2-20 mL) was administered per lesion. Patients were followed up for a mean of 29 months (range, 1-80 months). No patient had an increase of 0.2 mg/dL (17.7 mumol/L) or greater in mean serum creatinine level during the follow-up period. Two of the 16 patients (12%) required repeat embolization due to AML regrowth (n = 1) or reperfusion (n = 1) seen at surveillance imaging. One of the 16 patients (6.2%) had an AML hemorrhage 59 months after AML embolization.

CONCLUSIONS

Embolization of giant renal AMLs to decrease the risk of bleeding can be done safely without loss of renal function. Although recurrence was infrequent, additional treatment may be necessary and giant renal AMLs should be followed up with serial imaging studies.

Type 2 endoleak embolization comparison: translumbar embolization versus modified transarterial embolization

PURPOSE

To evaluate the success of endoleak repair using translumbar (TL) endoleak embolization compared with a transarterial (TA) technique that involves embolization of the endoleak cavity itself in addition to the feeding artery.

MATERIALS AND METHODS

Eighty-four patients (mean age, 78.2 years; age range, 58-94 years) with type 2 endoleaks were included in this retrospective study. Patients underwent either TL endoleak embolization or TA embolization between January 2002 and December 2007. TA embolization involved entering the endoleak cavity through the inferior mesenteric or lumbar artery. Both the endoleak cavity and the feeding artery were then embolized by using coils through a microcatheter. TL embolizations were performed by using standard technique with coils and n-butyl cyanoacrylate as the embolization agents. Clinical success was defined as the absence of an endoleak and/or aneurysm enlargement at follow-up CT angiography. Statistical comparison was performed with the Fisher exact test.

RESULTS

Endoleak repair was successful in 72% (45/62) of the TL embolizations and 78% (18/23) of the TA embolizations, with a mean follow-up of 18.7 months (range, 1-84 months). There was no significant difference in clinical success between the two groups (P = .41). There were two (3.2%) complications in the TL group and no complications in the TA group.

CONCLUSIONS

The effectiveness of the TA endoleak embolization technique, which involves embolizion of the endoleak cavity and the feeding artery, is similar to that of TL embolization for treatment of type 2 endoleaks.

Thoracic endoleak embolization using a direct percutaneous puncture of the endoleak through lung parenchyma

An 84-year-old patient presented with an endoleak after endovascular repair of a ruptured thoracic aortic aneurysm. The endoleak was thought to be a type II endoleak on computed tomographic (CT) angiography and was not visualized on angiography. The endoleak was accessed via direct puncture of the endoleak sac through the pleura and lung parenchyma with use of fluoroscopic and C-arm CT guidance. The endoleak was embolized with platinum coils and n-butyl cyanoacrylate with no complications. Follow-up imaging with CT angiography at 43 days revealed no recurrent endoleak.

Endovascular repair of aortic disease: a venture capital perspective

Endovascular devices for the treatment of abdominal and thoracic aortic disease are poised to become the next $1 billion medical device market. A shift from open repair to endovascular repair, advances in technology, screening initiatives, and new indications are driving this growth. Although billion-dollar medical device markets are rare, this field is fraught with risk and uncertainty for startups and their venture capital investors. Technological hurdles, daunting clinical and regulatory timelines, market adoption issues, and entrenched competitors pose significant barriers to successful new venture creation. In fact, the number of aortic endografts that have failed to reach commercialization or have been pulled from the market exceeds the number of Food and Drug Administration-approved endografts in the United States. This article will shed some light on the venture capital mind-set and decision-making paradigm in the context of aortic disease.

Large or small bore, push or pull: a comparison of three classes of percutaneous fluoroscopic gastrostomy catheters

PURPOSE

To compare the tube performance and complication rates of small-bore, large-bore push-type, and large-bore pull-type gastrostomy catheters.

MATERIALS AND METHODS

A total of 160 patients (74 men, 86 women; mean age, 66.9 years, range, 22-95 y) underwent percutaneous fluoroscopic gastrostomy placement between January 2004 and March 2006. Choice of catheter was based on the preference of the attending radiologist. Data were collected retrospectively with institutional review board approval. Radiology reports provided information on the catheter, indication for gastrostomy, technical success, and immediate outcome. Chart review provided data on medical history, postprocedural complications, progress to feeding goal, and clinical outcomes. Statistical analysis was performed to compare the three classes of gastrostomy catheters.

RESULTS

All 160 catheters were placed successfully. Patients who received small-bore catheters (14 F; n = 88) had significantly more tube complications (17% vs 5.6%) and were less likely to meet their feeding goal (P = .035) compared with patients with large-bore catheters (20 F; n = 72). No difference was observed in terms of major or minor complications. Large-bore push-type (n = 14) and pull-type catheters (n = 58) were similar in terms of complication rates. Patients who received large-bore push-type catheters achieved their feeding goals in significantly less time than those with large-bore pull-type catheters (average, 3.8 days vs 6.0 days; P = .04).

CONCLUSIONS

Patients who received small-bore gastrostomy catheters are significantly more prone to tube dysfunction. Large-bore catheters should be preferentially used, with push-type catheters performing better with regard to the time to achieve feeding goal.

Combination embolization and radiofrequency ablation therapy for renal cell carcinoma in the setting of coexisting arterial disease

The present report describes two cases of T1b (>4 cm) renal cell carcinoma (RCC) treated with superselective embolization and radiofrequency ablation in the setting of renal artery stenosis and abdominal aortic aneurysm, respectively. In the first case, a solitary functioning kidney was treated with stent placement immediately before RCC embolization. In the second case, a brachial artery approach was used for RCC embolization after a failed femoral approach secondary to an abdominal aortic aneurysm. These cases illustrate the utility of combination therapy for T1b RCC and emphasize the need for interventional radiologists and interventional oncologists to possess the requisite endovascular skills to manage anatomic challenges from coexisting arterial disease when performing image-guided tumor interventions.

Chemoembolization and bland embolization of neuroendocrine tumor metastases to the liver

PURPOSE

To assess the toxicity and efficacy of chemoembolization and bland embolization in patients with neuroendocrine tumor metastases to the liver.

MATERIALS AND METHODS

A total of 67 patients underwent 219 embolization procedures: 23 patients received primarily bland embolization with PVA with or without iodized oil and 44 primarily received chemoembolization with cisplatin, doxorubicin, mitomycin-C, iodized oil, and polyvinyl alcohol. Clinical, laboratory, and imaging follow-up was performed 1 month after completion of therapy and every 3 months thereafter. Patients with disease relapse were treated again when feasible. Toxicity was assessed according to National Cancer Institute Common Toxicity Criteria for Adverse Events, version 3.0. Efficacy was assessed by clinical and morphologic response. Time to progression (TTP), time to treatment failure, and survival were estimated by Kaplan-Meier analysis.

RESULTS

Ten of 67 patients (15%) were lost to follow-up. The mortality rate at 30 days was 1.4%. Toxicities of grade 3 or worse in severity occurred after 25% of chemoembolization procedures and 22% of bland embolization procedures (odds ratio, 1.2; 95% CI, 0.4-4.0). Mean length of stay was 1.5 day in both groups. Rates of freedom from progression at 1, 2, and 3 years were 49%, 49%, and 35% after chemoembolization and 0%, 0%, and 0% after bland embolization (log-rank test, P = .16). Among the subgroup with carcinoid tumors, the proportions without progression were 65%, 65%, and 52% after chemoembolization and 0%, 0%, and 0% after bland embolization (log-rank test, P = .08). Patients treated with chemoembolization and bland embolization experienced symptomatic relief for means of 15 and 7.5 months, respectively (P = .14). Survival rates at 1, 3, and 5 years after therapy were 86%, 67%, and 50%, respectively, after chemoembolization and 68%, 46%, and 33%, respectively, after bland embolization (log-rank test, P = .18).

CONCLUSIONS

Chemoembolization was not associated with a higher degree of toxicity than bland embolization. Chemoembolization demonstrated trends toward improvement in TTP, symptom control, and survival. Based on these results, a multicenter prospective randomized trial is warranted.