Karthik Kasirajan

Endovascular Repair for Diverse Pathologies of the Thoracic Aorta: An Initial Decade of Experience

BACKGROUND Endovascular grafts have rapidly evolved as a minimally invasive treatment for a variety of acute and chronic disorders of the thoracic aorta. Application of this technology at a single center is reported. STUDY DESIGN Between 1998 and 2007, 197 patients underwent thoracic endovascular aortic repair. Primary indications included degenerative aneurysms (n = 121), type B aortic dissection (n = 44), mycotic aneurysms (n = 9), traumatic disruptions (n = 9), intramural hematoma (n = 5), pseudoaneurysm (n = 4), and miscellaneous pathology (n = 5). An analysis of patient demographics, periprocedural records, complications, reinterventions, and survival was conducted. RESULTS Thirty-day mortality was 6%, which was lowest among patients undergoing treatment for a degenerative thoracic aortic aneurysm (2.4%, 3 of 121). Major adverse events included stroke in 3%, spinal cord ischemia in 2%, peripheral vascular repair in 4.5%, renal failure in 4.5%, and open conversion in one patient (0.5%). Both preoperative serum creatinine (odds ratio 1.44, 95% CI 1.02 to 2.04, p = 0.039) and number of endograft components (odds ratio 1.43, 95% CI 1.01 to 2.01, p = 0.043) were predictors of major adverse events. Kaplan-Meier analysis revealed a reduction in late survival among patients with preoperative creatinine >or=1.8 mg/dL (p < 0.001). One- and 5-year intervention-free survivals were 77%+/-3% and 41%+/-6%, respectively. CONCLUSIONS Thoracic endovascular aortic repair represents an effective treatment for a variety of pathologic states. But the risk-benefit analysis for thoracic endovascular aortic repair should carefully consider the extent of disease, pathologic condition, and renal function.

The phase I multicenter trial (STAPLE-1) of the Aptus Endovascular Repair System: Results at 6 months and 1 year

OBJECTIVE This phase I IDE study (STAPLE-1) evaluated the primary endpoints of safety (major device-related adverse events at 30 days) and feasibility (successful deployment of all endograft components) of the Aptus Endovascular abdominal aortic aneurysm (AAA) Repair System (Aptus Endosystems, Inc, Sunnyvale, Calif) to treat AAAs. METHODS A prospective, single arm Federal Drug Administration (FDA) Phase I IDE study was performed. The Aptus endograft is a three-piece modular device with a flexible unsupported main body and two fully supported limbs in a 5.3 mm outer diameter (OD) (16F) delivery system for all iliac limbs and two of three main body sizes. The largest main body (29 mm diameter) is in a 6 mm (18 F OD) delivery system. EndoStaples measuring 4 mm (length) by 3 mm (diameter) designed to provide transmural graft fixation to the adventitia are applied independent of the endograft delivery system. Inclusion criteria included a proximal aortic neck length of 12 mm and iliac landing zone of 10 mm. Secondary endpoints included freedom from endoleaks, rupture, migration, and device integrity. RESULTS Twenty-one (21) patients were enrolled at five centers. All patients received the Aptus Endograft and EndoStaples. Ninety-six EndoStaples (range, 2-10; median, 4) were implanted. All patients (n = 21) completed 1-month and 6-month follow-up evaluation and 14 completed 1-year follow-up. Two proximal cuffs and one limb extension were used as adjunctive endograft components at implantation. Three secondary interventions were performed in 2 patients for limb thrombosis. There were no EndoStaple-related adverse events, device integrity failures, migrations, or conversions. CONCLUSION These results of the STAPLE-1 trial document the acute safety and feasibility of the Aptus Endograft and EndoStaples. Early follow-up demonstrates excellent 6-month and 1-year results. A pivotal phase II trial is underway at 25 US centers.

Branched Grafts for Thoracoabdominal Aneurysms: Off-Label Use of FDA-Approved Devices

Purpose To report off-label use of approved off-the-shelf endografts with no modification to the devices for the management of thoracoabdominal aneurysms (TAAA). Technique The parallel endograft octopus technique is demonstrated in a 68-year-old woman with a past history of open TAAA repair with a patch reimplant of the visceral vessels who now presented with back pain. Non-contrast computed tomography revealed a 6.8-cm aneurysm of the visceral segment involving the celiac trunk, superior mesenteric artery (SMA), and right renal artery. As she was at high risk for redo surgery due to significant pulmonary dysfunction, she was an ideal candidate for a branched graft, but she could not travel to an investigational site for a custom graft. At surgery, 4 sheaths were introduced, 2 retrograde (18-F DrySeal) and 2 (8-F) antegrade, via the femoral arteries. The 18-F sheaths on both sides were connected to the 8-F sheaths for continued limb perfusion. Via an axillary conduit, a 12-F, 80-cm sheath was introduced into the proximal thoracic aorta over a stiff wire. Subsequently, two 28-mm Excluder endografts were introduced via the bilateral 18-F femoral sheaths and positioned side by side in the descending thoracic aorta such that the lower end of the Excluder limbs were positioned ≥2 cm above the target visceral vessels. Viabahn stent-grafts were then deployed in the celiac axis, SMA, and right renal artery from the axillary conduit. Subsequently, a 23-mm Excluder was deployed within the distal end of the upsized limb and extended to both common iliac arteries. Imaging at 6 months demonstrated no endoleaks, with good flow to all visceral vessels. Conclusion The parallel endograft octopus technique described here, which has been applied successfully in 9 cases thus far, is a relatively simple method using currently available devices with no requirement for device modification or customization. Although this technique shows promise, long-term data will be required to prove efficacy. This technique demonstrates a concept for future development of branched graft technology.

Contralateral occlusion is not a clinically important reason for choosing carotid artery stenting for patients with significant carotid artery stenosis

OBJECTIVE Contralateral carotid artery occlusion by itself carries an increased risk of stroke. Carotid endarterectomy (CEA) in the presence of contralateral carotid artery occlusion has high reported rates of perioperative morbidity and mortality. Our objective was to determine if there is a clinical benefit to patients who receive carotid artery stenting (CAS) compared to CEA in the presence of contralateral carotid artery occlusion. METHODS We conducted a retrospective medical chart review over a 4.5-year institutional experience of persons with contralateral carotid artery occlusion and ipsilateral carotid artery stenosis who underwent CAS or CEA. The main outcome measures were 30-day cardiac, stroke, and mortality rate, and midterm mortality. RESULTS Of a total of 713 patients treated for carotid artery stenosis during this time period, 57 had contralateral occlusion (~8%). Thirty-nine of these patients were treated with CAS, and 18 with CEA. The most common indications for CAS were prior neck surgery (18), contralateral internal carotid occlusion (nine), and prior neck radiation (seven). The average age was 70 ± 8.5 for CEA and 66.7 ± 9.3 for CAS (P = .20). Both groups were predominantly men (CEA 12 of 18; CAS 28 of 39; P = .76), with similar prevalence of symptomatic lesions (CEA 8 of 18, CAS 20 of 39; P = .77). Two patients died within 30 days in the CAS group (5%). No deaths occurred within 30 days in the CEA group (P = .50); the mortality rate for CAS and CEA combined was 3.5%. No perioperative strokes or myocardial infarction occurred in either group. Two transient ischemic attacks occurred after CAS. At mean follow-up of 29.4 ± 16 months (CEA) and 28 ± 14.4 months (CAS; range, 1.5-48.5 months), seven deaths occurred in the CAS group and one in the CEA group (17.9% vs 5.5%; P = .40). There were two reinterventions in the CAS group for in-stent restenosis and there were no reoperations in the CEA group. CONCLUSIONS Although CEA and CAS can both be performed with good perioperative results and acceptable midterm mortality, the observed outcomes do not support use of contralateral carotid artery occlusion as a selection criterion for CAS over CEA in the absence of other indications.

Incidence of and outcomes after misaligned deployment of the Talent Thoracic Stent Graft System

OBJECTIVE Various types of device-specific adverse events can occur during deployment of thoracic stent grafts due to the high flow rate and severe aortic angulation that is often encountered in the thoracic aorta. This study assessed the incidence, etiology, and overall effect of misaligned deployment of the Talent Thoracic Stent Graft (TSG) System. Techniques to predict and avoid this complication are discussed. METHODS Data collection included pivotal-trial follow-up, direct surveys of centers inside and outside the United States and principal investigators, a targeted literature search, and review of complaint files. Misaligned deployment was considered to occur when the proximal covered or uncovered stent apices of a thoracic stent graft folded back on itself and remained nonparallel to the wall of the aorta after deployment had been completed. RESULTS Of about 20,305 deployments to date of the Talent TSG, 24 misaligned deployments were identified for an incidence of 0.1%. Nineteen (79%) events occurred during treatment of degenerative aneurysms or penetrating ulcers, four (17%) during treatment of dissections, and the underlying pathology could not be determined for one patient. The misalignment was noted at the proximal end of the stent graft in 15 patients (63%), and the other 9 events (37%) occurred at the graft overlap junction. Two events were treated intraoperatively, with a second overlapping device placed in one patient and a snare used to reposition the proximal stent in another. Adverse clinical events occurred in three patients and included a persistent type I endoleak, continued false lumen perfusion in a patient with dissection, and delayed retrograde type A dissection in a patient undergoing total arch repair. No intraoperative contrast extravasation or computed tomography evidence of perforation was noted. There were no perioperative deaths or cerebrovascular events, with one report of paraplegia among the 24 patients in this series. CONCLUSION Misaligned deployment is an unusual phenomenon that tends to occur in the context of certain well-defined anatomic conditions in the thoracic aorta. To date, most of these events have not led to significant adverse sequelae. However, careful patient selection, periprocedural imaging, and case planning can help to identify anatomies in which misaligned opening is likely to occur, allowing physicians to avoid this complication.

A Single-Institution Experience with the AneuRx Stent Graft for Endovascular Repair of Abdominal Aortic Aneurysm

We report our experience of endovascular repair of infrarenal abdominal aortic aneurysms (EVAR) using the modular AneuRx Stent Graft System. We retrospectively reviewed the outcomes of 113 patients who underwent EVAR with the AneuRx system performed at our institution between October 1999 and August 2003. The mean age of this group was 72.5 years, with 71% (n = 80) over the age of 70 years and 95% (n = 107) males. Aneurysm diameter ranged 4.0-9.0 cm, with 33% (n = 37) >6.0 cm. The average duration of late follow-up was 32.6 +/- 24.8 months (median = 37). Successful deployment of the modular AneuRx system was noted in all patients. There were no immediate operative conversions, deaths within 24 hr of operation, or type I or III endoleaks observed at the completion of the procedure. Thirty-day mortality was 3.5% (n = 4). Acute deployment-related complications occurred in 10% (n = 13) of patients and included misdeployment, operative bleeding, arterial perforation/dissection, and access site complications. Acute systemic complications were present in nine patients, predominantly renal and cardiac complications. An endoleak noted at any time occurred in 25% of patients, with 40% of those requiring a secondary intervention. Two patients suffered late aneurysm rupture due to a type I endoleak and graft infection. Kaplan-Meier analysis revealed 5-year freedom from secondary intervention of 72.4%; freedom from aneurysm-related death of 93.9%; and probability of survival based on all-cause mortality of 60.1%. Endovascular treatment with the modular AneuRx Stent Graft System is safe and effective, producing acceptable rates of disease-free survival and mid-term clinical outcome.

Commentary: Endovascular aneurysm treatment in patients with vasculo-Behçet disease.

Shim and colleagues from Seoul’s Yonsei University College of Medicine have presented a retrospective analysis of 912 patients diagnosed with Behçet disease. This group of physicians performed endovascular interventions for 20 aneurysms with few re-interventions (18.8%) required during a 4-year followup. The patency for these stent-grafts at 24 months was a respectable 89%. In comparison, open surgical bypass of 8 aneurysms resulted in a re-intervention rate of 42.9% during a 2-year follow-up. Interestingly, pseudoaneurysm formation was not predictable and did not correlate with disease activity or immunosuppressive therapy. Despite the large number of Behçet disease patients seen at their institution, the authors encountered vascular aneurysms rarely. The infrequent nature of aneurysms in patients with Behçet disease prevents a large prospective study evaluating open surgery versus endovascular technique. Regardless, the authors have presented data that would compel one to take the endovascular route if feasible. Based on my personal experience (which is smaller than the current report), a few issues come to mind. The diagnosis can be missed due to the rare nature of the disease and the absence of definitive clinical tests. I would suggest any patient #55 years of age with aneurysms involving large and medium-sized vessels should have a sedimentation rate and a C-reactive protein evaluation. The combination of deep vein thrombosis (DVT) and aneurysm in a young patient should immediately raise the suspicion for Behçet syndrome. Most of my patients have also been of African-American ethnicity. Although the authors suggest positron emission tomography (PET) to evaluate disease activity, this has not been useful in our experience. Recently, a patient with a prior aortobi-iliac bypass for an infrarenal abdominal aortic aneurysm presented with large distal anastomotic pseudoaneurysm rupture. She had a prior history of DVT and had an elevated sedimentation rate; still, the diagnosis had been missed. We obtained a PET scan to exclude an infective etiology, and the PET was negative despite serological markers of disease activity. This has also been our experience with PET scans in other forms of vasculitis. Additionally, routine follow-up scans have not necessarily been predictive of pseudoaneurysm formation, as most of these anastomotic aneurysms presented with a prior normal computed tomography scan and sudden rupture. In conclusion, I agree with the authors’ approach of an endovascular-first technique with close follow-up of serological markers to control disease activity and shorter imaging follow-up studies.