Hernán G. Bertoni

Left subclavian artery coverage during thoracic endovascular aortic aneurysm repair does not mandate revascularization

OBJECTIVE This study assessed the risk of left subclavian artery (LSA) coverage and the role of revascularization in a large population of patients undergoing thoracic endovascular aortic aneurysm repair. METHODS A retrospective multicenter review of 1189 patient records from 2000 to 2010 was performed. Major adverse events evaluated included cerebrovascular accident (CVA) and spinal cord ischemia (SCI). Subgroup analysis was performed for noncovered LSA (group A), covered LSA (group B), and covered/revascularized LSA (group C). RESULTS Of 1189 patients, 394 had LSA coverage (33.1%), and 180 of these patients (46%) underwent LSA revascularization. In all patients, emergency operations (9.5% vs 4.3%; P=.001), renal failure (12.7% vs 5.3%; P=.001), hypertension (7% vs 2.3%; P=.01), and number of stents placed (1=3.7%, 2=7.4%, ≥3=10%; P=.005) were predictors of SCI. History of cerebrovascular disease (9.6% vs 3.5%; P=.002), chronic obstructive pulmonary disease (9.5% vs 5.4%; P=.01), coronary artery disease (8.5% vs 5.3%; P=.03), smoking (8.9% vs 4.2%) and female gender (5.3% men vs 8.2% women; P=.05) were predictors of CVA. Subgroup analysis showed no significant difference between groups B and C (SCI, 6.3% vs 6.1%; CVA, 6.7% vs 6.1%). LSA revascularization was not protective for SCI (7.5% vs 4.1%; P=.3) or CVA (6.1% vs 6.4%; P=.9). Women who underwent revascularization had an increased incidence of CVA event compared with all other subgroups (group A: 5.6% men, 8.4% women, P=.16; group B: 6.6% men, 5.3% women, P=.9; group C: 2.8% men, 11.9% women, P=.03). CONCLUSIONS LSA coverage does not appear to result in an increased incidence of SCI or CVA event when a strategy of selective revascularization is adopted. Selective LSA revascularization results in similar outcomes among the three cohorts studied. Revascularization in women carries an increased risk of a CVA event and should be reserved for select cases.

Carotid artery dissection: endovascular treatment. Report of 12 patients.

The purpose of this article is to report our experience with endovascular treatment of internal carotid artery (ICA) dissection with the use of stents.

Midterm Results of a Sirolimus-Eluting Stent Implanted for Recurrent Carotid In-Stent Restenosis

One of the concerns about carotid artery stenting (CAS) is the development of restenosis. Although the incidence of restenosis is low (3% to 8% in large series) due to the large reference vessel diameter, the number of cases will continue to rise as more CAS procedures are performed each year. While drug-eluting stent implantation has replaced balloon angioplasty and brachytherapy for the treatment of in-stent restenosis in the coronary arteries, there is scarce information regarding their use for carotid in-stent restenosis. In 2007, Iancu and Lazar reported sustained patency of a drug-eluting stent 1 year after treatment for carotid in-stent restenosis. We have recently documented 30-month follow-up in a patient we treated for recurrent in-stent restenosis with a drugeluting stent. The 53-year-old diabetic woman with multiple comorbidities was seen for symptoms of bilateral carotid artery disease. Her left internal carotid artery (ICA) was chronically occluded, and the right ICA had an 80% stenosis (Figure, A); the intracranial circulation was free of hemodynamically significant lesions. An 8340-mm Wallstent under FilterWire EZ embolic protection (Boston Scientific, Natick, MA, USA) was implanted in the right ICA with excellent results (Figure, B). The patient was discharged on aspirin and clopidogrel, but 1 year later, she was seen for dizziness and left arm paresthesia. A high-grade in-stent restenosis was treated with balloon dilation without complications. Nine months later, the patient was admitted for unstable angina and left arm paresthesia. Ultrasound suggested a highgrade recurrent in-stent restenosis (Figure, C). Surgery was proposed but dismissed by the vascular surgeon due to the high cervical location of the stenosis and contralateral carotid occlusion, so we implanted a 3.5-333mm Cypher coronary stent (Cordis, Miami, FL, USA) under cerebral protection (Figure, D,E); the stent was further expanded with a 4.5-mm balloon. The patient was discharged on longterm aspirin and clopidogrel therapy. Thirty months later, she was admitted for left leg critical ischemia, but she was free of any neurological deficit or symptom. Carotid angiography showed no evidence of restenosis (Figure, F) in the right ICA stent.

Size of the Proximal Neck in AAAs Treated with Balloon-Expandable Stent-Grafts: CTA Findings in Mid- to Long-term Follow-up

Purpose: To determine the evolution of the proximal aortic neck diameter in mid- to long-term follow-up after endovascular aneurysm repair of abdominal aortic aneurysm (AAA) with a balloon-expandable stent-graft. Methods: Thirty patients (27 men; average age 71 years, range 56–87) with infrarenal AAAs were treated with the SETA-Latecba balloon-expandable stent-graft (6 aortomonoiliac and 24 bifurcated configurations). Follow-up ranged from 4 to 8 years (mean 73.4 months). Computed tomography was done systematically before the procedure, after implantation (1–3 months), at 1 year, and annually thereafter. The last follow-up scan was utilized to measure the proximal neck for purposes of comparison with baseline and the initial post-implant scans. Results: Five patients died during follow-up of causes unrelated to the procedure. No endoleaks or graft migrations were observed. The pre-deployment proximal neck diameter (a) averaged 23.4 mm (range 18–32), the diameter after deployment of the stent-graft (b) averaged 24.9 mm (range 18–34), and the most recent follow-up proximal neck measurement (c) averaged 23.8 mm (range 18–31). Comparing the last follow-up to the post-implant measurements (c–b), the neck diameter decreased in 15 (50%) patients [7 with short necks (i.e., <15 mm)] and remained unchanged (no variation) in 15 (50%) patients (4 with short necks). All patients treated with the SETA-Latecba balloon-expandable stent-graft showed stability of the proximal aortic neck diameter in mid- to long-term follow-up. Conclusion: The study showed that the diameter reached at initial deployment did not increase further in the long term, which supports the safety and reliability of this modular balloon-expandable stent-graft and illustrates that this device does not produce dilatation of the proximal neck after deployment. Future dilatation of the aortic neck is unlikely, and consequently, migration or delayed type I endoleak are also unlikely.

A Branched, Balloon-Deployable, Aortomonoiliac Stent-Graft for Treatment of AAA in a Patient with a Solitary Intrapelvic Kidney

Purpose: To report the use of a branched, balloon-deployable stent-graft to treat abdominal aortic aneurysm (AAA) in the setting of a solitary kidney. Case Report: A 72-year-old man with a solitary intrapelvic kidney and multiple comorbid conditions was diagnosed with an asymptomatic 5.3-cm abdominal aortic aneurysm (AAA); the renal artery emerged from the aneurysm sac. A customized branched, balloon-deployable, aortomonoiliac stent-graft was utilized to exclude the AAA and preserve perfusion to the single renal artery. A synthetic bypass was then implanted to restore perfusion to the contralateral limb. The diameter of the aneurysm decreased from 5.3 to 2.7 cm at 18 months. The renal artery was patent without evidence of stenosis; renal function was normal. Conclusion: The deployment of a novel branched stent-graft represents an interesting alternative approach to the treatment of a juxtarenal aneurysm.

Transrenal Deployment of a Modular Stent Graft to Repair AAAs with Short Necks: Experiments in Dogs

Severely angulated (> 60°) or short (< 15mm) proximal necks remain significant anatomical limitations for endovascular stent-graft repairs for abdominal aortic aneurysms. Ensuring proper proximal fixation of the stent-graft to the host artery without the short-or long-term risks of endoleak or migration represents a particular technical challenge for these anatomical circumstances. An innovative balloon expandable stent combined with a weft-knitted prosthesis was specifically designed for these situations by modelling the stent to the neck anatomy without overdistension or potential barotrauma allowing better incorporation of the device. The Latecba stent-graft consists of a 2 parts modular design. The first one, Module A, is deployed at the transrenal level and consists of a Palmaz type stent whose first half is bare and second half is sutured to a crimped weft-knitted polyester graft whose distal end holds a constriction. The second Module B is a non-crimped weft-knitted graft attached to 2 stainless steel stents. The first stent is entirely contained in the proximal textile tube, allowing fixation to module A. The second stent, which is left uncovered over the distal third, ensures proper fixation of the stent-graft distally. Following the creation of a prosthetic aneurysm in the infrarenal aorta in 32 dogs, 29 received the Latecba stent-graft for scheduled durations of 10 days, 1 month, 3 months and 6 months. Proper deployment of the stent-grafts was achieved without difficulty. All 29 animals survived and the devices were all patent at sacrifice. No device defects or migrations were observed and the stent-grafts proved to be efficient in this setting to exclude the aneurysm. Analyses of the explanted devices (gross observations, RX, CT scan, IVUS, angioscopy) confirmed the stability of this modular stent-graft. Further on-going clinical investigations are warranted to validate this concept before this stent-graft becomes commercially available without any restriction.

Analysis of Explanted Latecba Modular Stent-grafts Deployed Transrenally to Repair AAAs with Short Necks in 29 Dogs

Twenty-nine modular stent-grafts deployed transrenally to repair AAAs with short necks in dogs were harvested at autopsy of the animals after scheduled durations of implantations of 10 days, one month, three months, and six months. Analyses of the explanted devices included non-destructive techniques such as gross observations, X-rays CT scan, IVUS and angioscopy. Further to appropriate dissection, histological investigations were carried out by means of scanning electron microscopy (SEM) and light microscopy. All the 29 specimens were extensively encapsulated with fibrous tissues but the fibrous capsule was thin in six of them; four capsules were ulcerated. The X-rays confirmed the stability of the devices that were still straight (12), slightly bent (12) or bent (4). The modules were misaligned in only one case. IVUS and angioscopy confirmed the patency of all the stent-grafts with thin internal capsules both proximally and distally with variable capsulation in the mid-section of the grafts. The left renal artery orifices were found to be patent at dissection with no obstruction to flow. The luminal flow surface of the stent-grafts was smooth and glistening proximally and distally containing endothelial like cells and vasa-vasorum. Poor healing was noted in the aneurysm area. Transrenal deployment of this modular stent-graft is feasible and gave excellent results with regard to biofunctionality and biocompatibility. The device proved to be safe and efficient.

Incidence and Factors Influencing Medullary Ischemia during Endovascular Treatment of the Thoracic Aorta

Stent-graft placement in the thoracic aorta is a common procedure used in an increasing number of patients. Recent studies have demonstrated that the extensive coverage of the thoracic aorta is associated with the incidence of neurological complications. (1) Although reports in the international literature generally account for lower incidence of medullary ischemia (MI) during stent-graft placement than during conventional surgery, MI is still one of the most devastating and feared complications. (2, 3) Many factors have been found to promote MI, such as a history of previous treatment of abdominal aorta, hypotension during implantation, left subclavian artery coverage, and extent of covered aorta. (4) The purpose of this presentation was to analyze the incidence and identify the risk factors associated with MI in patients whose thoracic aorta was fully covered. Between April 1999 and December 2014, 176 patients underwent endovascular treatment in the thoracic aorta. Among these patients, 62 (48 men and 14 women), with average age of 59.95 years, received endovascular stent grafting of the thoracic aorta from the aortic arch to the celiac trunk due to true aneurysm (n=13), aortic dissection (n=42), intramural hematoma (n=4), post-traumatic pseudoaneurysm (n=2), and aortic ulcer (n=1). Table 1 shows patient demographic and clinical characteristics. All patients underwent computed tomography angiography before surgery. In 22 cases (35.48%) the left subclavian artery was intentionally occluded without a bypass as the proximal aortic neck length was <15 mm. (5) The celiac trunk was intentionally covered in 3 patients due to short distal aortic neck. Five patients received medullary protection through drainage of the spinal fluid. All these patients had undergone previous abdominal surgery. All the procedures were performed under general anesthesia and invasive blood pressure monitoring, maintaining mean arterial pressure above 90 mmHg. Technical implant success was defined as correct stent deployment without conversion to conventional surgery or evidence of immediate type I and III endoleaks. (6) Continuous variables were expressed as median and interquartile range (25-75), while categorical variables were expressed as percentages with their absolute values. The difference in survival rate at 1, 3 and 6 years was assessed with the Kaplan Meier method. Statistical analysis was performed with STATA 13 software package. Technical implant success was 96.7%, with two type I endoleaks (3.23%) at the end of the procedure, and perioperative mortality in 3 patients (4.84%). No conversion to conventional surgery was reported, and the causes of death were aortic rupture in one patient and multi-organ failure in the other two patients. The mean length of aortic coverage was 288 mm (range 200 to 360 mm). None of the patients whose left subclavian artery (35.48%) and celiac trunk (4.84%) were intentionally covered developed ischemia of the left upper limb or mesenteric artery, respectively. The incidence of MI was observed in 3 patients (4.83%), immediate in one and late in the other two. One of the patients had paraparesis in the coronary care unit 24 hours after treatment; the second patient developed retrograde ejaculation and paresthesia in both lower limbs 3 years after the procedure; and the third patient developed permanent paraplegia 4 years after the procedure. Survival rate at 1, 3, and 6 years was 76%, 69.91%, and 64.32%, respectively (Figure 1). Medullary ischemia is a severe complication during stent placement in thoracic aortic disease, with a reported frequency in the international literature ranging from 0% to 12%. (3-5) In our study, the incidence of MI was 4.83% (3 patients). The patient presenting paraparesis in the coronary care unit 24 hours after treatment, had been treated for thoracic aneurysm, and years before had received aortobifemoral bypass. He underwent drainage of the spinal fluid up to 10 mmHg through a spinal catheter placed during the intervention and was discharged asymptomatic 72 hours following the procedure. The second patient, treated for chronic dissection, who had undergone endovascular repair of the abdominal aorta, developed retrograde ejaculation and sudden paresthesias in both lower limbs 3 years after the procedure, which was corrected by stabilizing the blood pressure. The third patient, also treated for chronic aortic dissection, developed paraplegia 4 years after the procedure, probably due to atheromatous embolism in an aorta with multiple fibrolipid calcified plaques, remaining paraplegic during follow-up. Medullary ischemia after stent implantation in the thoracic aorta is more common when the arteries that supply the spinal cord are sacrificed (Adamkiewicz, intercostal and lumbar arteries), or after a period of severe hypotension or embolism caused by