Pasqualino Sirignano

Optical Coherence Tomography after Carotid Stenting: Rate of Stent Malapposition, Plaque Prolapse and Fibrous Cap Rupture According to Stent Design

OBJECTIVES This study aims to evaluate the rate of stent malapposition, plaque prolapse and fibrous cap rupture detected by optical coherence tomography (OCT) imaging according to carotid stent design. DESIGN It was a prospective single-centre study. MATERIALS AND METHODS Forty consecutive patients undergoing protected carotid artery stenting (CAS) and high-definition OCT image acquisition were enrolled in the study. OCT frames were analysed off-line, in a dedicated core laboratory by two independent physicians. Cross-sectional OCT images within the stented segment of the internal carotid artery were evaluated at 1-mm intervals for the presence of strut malapposition, plaque prolapse and fibrous cap rupture according to stent design. RESULTS Closed-cell design stents (CC) were used in 17 patients (42.5%), open-cell design stents (OC) in 13 (32.5%) and hybrid design stents (Hyb) in 10 (25%). No procedural or post-procedural neurological complications occurred (stroke/death 0% at 30 days). On OCT analysis the frequencies of malapposed struts were higher with CC compared to OC and Hyb (34.5% vs 15% and 16.3%, respectively; p < 0.01). Plaque prolapse was more frequent with OC vs CC (68.6% vs 23.3%; p < 0.01) and vs Hyb stents (30.8%; p < 0.01). Significant differences were also noted in the rates of fibrous cap rupture between CC and OC (24.2% vs 43.8%; p < 0.01), and between CC and Hyb (24.2% vs 39.6%; p < 0.01), but not between OC and Hyb stents (p = 0.4). CONCLUSION Intravascular OCT after CAS revealed that micro-defects after stent deployment are frequent and are related to the design of implanted stents. Stent malapposition is more frequent with CC stents, while plaque prolapse is more common with OC stents. It remains, however, unknown whether these figures now detected with OCT are of any clinical and prognostic significance.

Aortic neck evolution after endovascular repair with TriVascular Ovation stent graft

OBJECTIVE Aortic neck dilation has been reported after endovascular aneurysm repair (EVAR) with self-expanding devices. With a core laboratory analysis of morphologic changes, this study evaluated midterm results of aortic neck evolution after EVAR by endograft with no chronic outward force. METHODS This was a multicenter registry of all patients undergoing EVAR with the Ovation endograft (TriVascular, Santa Rosa, Calif). Inclusion criteria were at least 24 months of follow-up. Standard computed tomography (CT) scans were reviewed centrally using a dedicated software with multiplanar and volume reconstructions. Proximal aortic neck was segmented into zone A (suprarenal aorta/fixation area), zone B (infrarenal aorta, from lowest renal artery to the first polymer-filled ring), and zone C (infrarenal aorta, at level of the first polymer-filled ring/sealing zone). Images were analyzed for neck enlargement (≥2 mm), graft migration (≥3 mm), endoleak, barb detachment, neck bulging, and patency of the celiac trunk and superior mesenteric and renal arteries. RESULTS Inclusion criteria were met in 161 patients (mean age, 75.2 years; 92% male). During a mean follow-up period of 32 months (range, 24-50), 17 patients died (no abdominal aortic aneurysm-related death). Primary clinical success at 2 years was 95.1% (defined as absence of aneurysm-related death, type I or type III endoleak, graft infection or thrombosis, aneurysm expansion >5 mm, aneurysm rupture, or conversion to open repair). Assisted primary clinical success was 100%. CT scan images at a minimum follow-up of 2 years were available in 89 cases. Patency of visceral arteries at the level of suprarenal fixation (zone A) was 100%. Neither graft migration nor barb detachment or neck bulging was observed. None of the patients had significant neck enlargement. The mean change in the diameter was 0.18 ± 0.22 mm at zone A, -0.32 ± 0.87 mm at zone B, and -0.06 ± 0.97 mm at zone C. Changes at zone B correlated significantly with changes at zone C (correlation coefficient, 0.183; P = .05), whereas no correlation was found with zone A (correlation coefficient, 0.000; P = 1.0). CONCLUSIONS No aortic neck dilation occurred in this series at CT scan after a minimum 24-month follow-up. This may suggest that aortic neck evolution is not associated with EVAR at midterm follow-up when an endograft with no chronic outward radial force is implanted.

AAA with a Challenging Neck: Early Outcomes Using the Endurant Stent-Graft System

OBJECTIVES The efficacy and safety of endovascular aneurysm repair is disputable in aneurysms with a short, angulated, wide, conical, or thrombus-lined neck making a reliable seal difficult to achieve. The influence of a challenging neck on early results using the Endurant stent-graft system in high risk patients was investigated. MATERIALS AND METHODS A retrospective study conducted on a prospectively compiled database of 72 elective patients with challenging neck treated with the Endurant system (Endurant Stent Graft, Medtronic AVE, Santa Rosa, CA, USA). These patients were compared to a control group (n = 65) without significant neck problems. Endpoints were early technical and clinical success, deployment accuracy and differences in operative details at one month follow-up. Data are reported as mean and standard deviation or as absolute frequency and percentage (%). Normality distribution and homogeneity of variances were tested by Shapiro-Wilks and Levene tests, respectively. Inter-group comparisons for each variable were made by t-test or χ2-test or Fisher exact test. A p < 0.05 was considered statistically significant. RESULTS Mean age was 76.12 years; 76.6% were males. Risk factors and pre-operative variables did not differ significantly between the two groups. Mean neck length was 10.56 mm in patients with challenging anatomies and 22.85 mm in controls. Patients with a challenging neck differed significantly (p < 0.001) from controls in terms of mean infrarenal (37.67° vs. 20.12°) and suprarenal angle (19.63° vs. 15.57°); 82% of patients with a challenging neck were ASA III/IV (vs. 86%). Technical success was 100%, with four unplanned proximal extension in challenging group. No type I endoleaks or aneurysm-related deaths occurred in either group; major complications were 1.54% vs. 1.39% (p = 0.942). Operative details were similar in both groups. CONCLUSION Treatment with the Endurant stent-graft is technically feasible and safe, yielding satisfactory results even in challenging anatomies. Medium- and long-term data are needed to verify durability, but early results are promising.

Safety and Feasibility of Intravascular Optical Coherence Tomography Using a Nonocclusive Technique to Evaluate Carotid Plaques Before and After Stent Deployment

Purpose To evaluate the safety and feasibility of optical coherence tomography (OCT) in patients with carotid stenosis undergoing carotid artery stenting (CAS). Methods In a prospective study, 25 consecutive patients (15 men; mean age 74±4 years) undergoing protected CAS were enrolled and underwent high-definition (homoaxial resolution 10 μm) OCT image acquisition before stent deployment, immediately after stent placement, and following postdilation of the stent (3 scans/patient). Pullbacks were started during a nonocclusive flush, mechanically injecting 24 mL of 50% diluted contrast at 6 mL/s to displace blood from the artery. Two independent physicians judged the quality of images on a predefined 1–10 scale. The proportions of specific agreement and kappa values (κ) were calculated. Results No procedural or in-hospital neurological complications occurred (any stroke/death 0%). The technical success of OCT pullbacks was 97.3% (73/75). The total amount of contrast was 86±18 mL/patient. No significant alteration in glomerular filtration rate or any other significant adverse event occurred. The images obtained were of high quality (mean value 8.1 out of 10), with good inter- and intraobserver agreement (κ = 0.81–0.87 and κ = 0.95, respectively). OCT images revealed innovative features such as rupture of the fibrous cap, plaque prolapse, and stent malapposition in a high percentage of the patients (range 24%–100%). Conclusion Intravascular OCT during a nonocclusive flush appears to be feasible and safe in carotid arteries. Since some original and unexpected information after CAS has been made available for the first time at such a high definition, future studies with OCT should focus on the interaction between carotid plaque and stent design, which might revolutionize our understanding of the mechanisms of carotid stenting, as well as influence our clinical policies.

The Wonders of a Newly Available Post-analysis CT Software in the Hands of Vascular Surgeons

INTRODUCTION Endovascular treatment of abdominal aortic aneurysms has become a widespread and accepted practice in most Vascular Surgery centres. The optimal method to identify and characterise complications still awaits assessment. CASE REPORT An 83-year-old woman was admitted to our Institution for volumetric expansion of the aneurysm sac due to a suspected type II endoleak. Post-analysis, using OsiriX, revealed the presence of a hole at the distal portion of the main body in the docking zone near the flow divider. CONCLUSION OsiriX is an image processing software and an attractive alternative to dedicated workstations and allows rendering and analysis of numerous medical imaging modalities.

Preliminary Results from a National Enquiry of Infection in Abdominal Aortic Endovascular Repair (Registry of Infection in EVAR - R.I.EVAR)

BACKGROUND To preliminary report on epidemiology, risk factors, diagnosis, treatments, and outcomes in a multicenter series of patients treated for endovascular aortic repair (EVAR) infection and detected by an Italian National enquiry. METHODS From June 2012, 26 cases of abdominal aortic endograft infection were collected by a National Enquiry and recorded in the Italian National Registry of Infection in EVAR. Cases collected were available for patients submitted to EVAR implantation from January 2004 to June 2013. RESULTS Mean time from EVAR treatment to infection diagnosis was 20.5 ± 20.3 months (range, 1-72). In 6 cases (23.1%), an aortoenteric fistula (AEF) was detected. Positive microbiologic cultures were found in 20 patients (76.9%). More than 1 infectious agent was found in 6 cases (19.2%). EVAR infection treatment was conservative in 4 cases, endovascular in 2. Endograft excision was performed in 10 cases by conventional treatment (aortic stump + extra-anatomic bypass) and in 10 cases by in situ reconstruction (cryopreserved allograft or rifampin-soaked silver Dacron graft). A 30-day mortality was 38.4% (10 of 26 cases), 3 patients died from 2 to 24 months after infection treatment, accounting for a mean time from infection treatment to death of 1.25 ± 0.62 months. Mortality rates were 50% in all treatment groups. In those survived (13 of 26 cases) recurrence-free follow-up after infection treatment was 27.9 ± 22.4 months (range, 2-74). Four patients with AEF died in the first month after treatment (66.6%). Suprarenal endografts required supraceliac aortic cross-clamping for removal. Supraceliac cross-clamping was burdened by higher mortality rates than infrarenal cross-clamping (71.4% vs. 30.7%). CONCLUSIONS EVAR infection diagnosis is burdened by extremely high mortality rates. Prospective registries could help monitoring outcomes in EVAR infection patients and, possibly, developing new surveillance protocols in patients at high risk of recurrence.

Carotid Restenosis After Endarterectomy and Stenting: A Critical Issue?

BACKGROUND Carotid artery stenting (CAS) is currently considered a valid alternative to carotid endarterectomy (CEA) for the prevention of stroke in high-risk patients. One of the most important issues for both of these techniques is carotid restenosis. The aim of our study was to evaluate the incidence of post-CEA and post-CAS restenosis in a large cohort of patients in a single high-volume center. METHODS Between December 2000 and December 2010, 2453 CEA and 2628 CAS procedures were performed in the Vascular and Endovascular Surgery Unit at our institution. The mean age of patients was 73.8 years (range 55‒89 years), 78% of whom were men. Indications for carotid revascularization were: presence of symptomatic carotid artery stenosis of >70%, or asymptomatic stenosis of at least 80%, especially in patients with vulnerable plaques. RESULTS Mild and long-term results after CEA and CAS were similar. The overall perioperative neurologic complication rate (minor and major stroke) was similar in the 2 groups. At 1-year follow-up the restenosis rate after CEA was 1.58%. In-stent restenosis after CAS occurred in 1.67% of the procedures. All but 3 arteries had been treated for postsurgical restenosis. All lesions were approached secondarily with endovascular procedures. Statistical analysis demonstrated that post-CEA restenosis was the most important predictive factor for the development of in-stent restenosis after CAS. CONCLUSIONS This review of our 10-year experience confirms that patients who develop restenosis after CEA are also prone to developing in-stent restenosis after CAS.

Midterm results of proximal aneurysm sealing with the ovation stent-graft according to On-vs off-label use

Purpose: To compare the use of the Ovation stent-graft according to the ≥7-mm neck length specified by the original instructions for use (IFU) vs those treated off-label (OL) for necks <7 mm long. Methods: A multicenter retrospective registry (TriVascular Ovation Italian Study) database of all patients who underwent endovascular aneurysm repair with the Ovation endograft at 13 centers in Italy was interrogated to identify patients with a minimum computed tomography (CT) follow-up of 24 months, retrieving records on 89 patients (mean age 76.4±2.4 years; 84 men) with a mean follow-up of 32 months (range 24–50). Standard CT scans (preoperative, 1-month postoperative, and latest follow-up) were reviewed by an independent core laboratory for morphological changes. For analysis, patients were stratified into 2 groups based on proximal neck length ≥7 mm (IFU group, n=57) or <7 mm (OL group, n=32). Outcome measures included freedom from type Ia endoleak, any device-related reintervention, migration, and neck enlargement (>2 mm). Results: At 3 years, there was no aneurysm-related death, rupture, stent-graft migration, or neck enlargement. There were no differences in terms of freedom from type Ia endoleak (98.2% IFU vs 96.8% OL, p=0.6; hazard ratio [HR] 0.55, 95% CI 0.02 to 9.71 or freedom from any device-related reintervention (92.8% IFU vs 96.4% OL, p=0.4; HR 2.42, 95% CI 0.34 to 12.99). In the sealing zone, the mean change in diameters was −0.05±0.8 mm in the IFU group and −0.1±0.5 mm in the OL group. Conclusion: Use of the Ovation stent-graft in patients with neck length <7 mm achieved midterm outcomes similar to patients with ≥7-mm-long necks. These midterm data show that the use of the Ovation system for the treatment of infrarenal abdominal aortic aneurysm is not restricted by the conventional measurement of aortic neck length, affirming the recent Food and Drug Administration–approved changes to the IFU.

Inguinal field block for femoral artery exposure during endovascular aneurysm repair.

Purpose To analyze the feasibility and outcomes of an inguinal field block (IFB) for femoral artery exposure in patients undergoing elective endovascular aneurysm repair (EVAR). Methods Between January 2004 and June 2012, 784 patients (597 men; mean age 76 years) underwent elective EVAR via surgical cutdown to the common femoral arteries. The data from these procedures were retrospectively analyzed to determine the technical feasibility of IFB, need for conversion to general anesthesia, mortality, and complication rate. Results IFB was successfully performed in 768 (97.9%) patients. Conversion from IFB to general anesthesia was necessary in 11 (1.4%) patients owing to patient discomfort (n=3, 0.4%), anxiety (n=5, 0.6%), and persistent patient movement (n=3, 0.4%). The remaining 5 (0.7%) patients underwent EVAR under general anesthesia because they refused IFB. Technical success of EVAR was 99.7%; the mean operation time was 84 minutes and the radiation time was 13 minutes. The mean hospital stay was 3.7 days; no patient required intensive care. At 6 months, there were no reports of local/systemic complications related to IFB, such as infection, seroma, hematoma, nerve injury, or allergic/toxic reactions. Conclusion Our study demonstrated that performing EVAR with femoral cutdown under IFB is a feasible, safe, and effective surgical and anesthetic combination, with very little need for conversion to general anesthesia.

Infective etiology affects outcomes of late open conversion after failed endovascular aneurysm repair

Purpose: To retrospectively review all patients undergoing late open conversion (LOC) after endovascular aneurysm repair (EVAR) in order to identify any clinical or technical predictors of poor outcome. Methods: Twenty-six consecutive patients (24 men; mean age 74.7±8.3 years) underwent LOC between June 2006 and April 2013 at our institution. The mean interval from index EVAR to LOC was 40.4±29.2 months (range 5–93 months). The indication for LOC was endoleak in 14 (54%) patients and infection in 12 (46%): 2 (8%) patients with endoleak had a ruptured aneurysm and 6 (23%) patients with infection had a recurrent secondary aortoesophageal fistula (sAEF). Results: In all 12 cases of infection and in 12 of 14 endoleaks, the entire endograft was explanted. A rifampin-soaked Dacron silver graft was implanted in all patients with infection. Patients with any infection and with recurrent AEF required more blood units than patients with endoleak (6.40 vs. 1.86, p=0.045; 6.76 vs. 1.86, p=0.0036, respectively). Compared with endoleak, the duration of conversions in the setting of infection (274 vs. 316 minutes, p=0.42) and recurrent sAEF (274 vs. 396 minutes, p=0.021) was longer. All patients with recurrent sAEF died at a mean 3.0±2.5 days after LOC from proximal anastomosis disruption and hemorrhagic shock (n=2), myocardial infarction (n=2), acute stroke (n=1), or persistent sepsis (n=1). Perioperative mortality was significantly higher in patients with endograft infection (6/12, p=0.002) and in cases of supraceliac cross-clamping (4/6, p=0.003). The association of infection with supraceliac cross-clamping was a strong predictor for perioperative mortality (p<0.001). Conclusion: In our experience, endograft infection led to greater perioperative mortality after LOC. Recurrent aortoenteric fistula in association with supraceliac cross-clamping is a strong predictor of poor outcome. Patients surviving the perioperative period may have good chances of long-term survival.