Five-year results of thoracic endovascular aortic repair with the Zenith TX2

Analysis of Risk Factors for Early Type I Endoleaks After Thoracic Endovascular Aneurysm Repair

Purpose: To evaluate risk factors for early (<30 days) type I endoleak following thoracic endovascular aortic repair (TEVAR). Methods: A retrospective study was conducted of 439 consecutive patients (mean age 74.0±10.0 years; 333 men) who underwent TEVAR at a single center between June 2006 and June 2013. Pathologies included 237 aortic arch aneurysms and 202 descending thoracic aortic aneurysms (dTAA). Maximum TAA diameter was 63.6±13.7 mm. Among the distal aortic arch aneurysms, 124 required coverage of the left subclavian artery (LSA), while the remaining 113 arch aneurysms had debranching (n=40), the chimney technique (n=52), and a branched stent-graft (n=13). Eight patients with dilatation of the ascending aorta underwent arch replacement with elephant trunk prior to TEVAR. Predictive factors for type I endoleak were explored in univariate analysis and examined for each outcome using logistic regression models; results are given as the odds ratio (OR) and 95% confidence interval (CI). Results: Among 439 TEVAR cases, 37 (8.4%) had type I endoleaks on imaging at 1 month; 31 were in the 237 arch cases (13.1%). Endoleak investigation by site indicated a low incidence (3.0%) for dTAAs and markedly low (1.4%) in zone 4. Significantly more endoleaks were observed in zones 0–2 than in zone 4 (p<0.001). On univariate analysis, significant associations were found between endoleak and LSA coverage (OR 5.8, 95% CI 2.4 to 14.4, p<0.001), operative time ≥240 minutes (OR 3.7, 95% CI 1.5 to 6.2, p=0.002), and ≥270 mL of contrast (OR 2.8, 95% CI 1.4 to 5.8, p=0.004). Among the aortic branch reconstruction procedures, the chimney technique was the only maneuver associated with a significant risk of endoleak (OR 5.3, 95% CI 2.3 to 11.2, p<0.001). Arch state was not correlated with endoleaks, but ≥38-mm proximal neck diameter (OR 3.6, 95% CI 1.2 to 10.8, p=0.023), stent-graft diameter ≥40 mm (OR 9.9, 95% CI 1.4 to 30.5, p=0.015), and excessively oversized (≥14%) stent-grafts (OR 3.5, 95% CI 1.2 to 10.3, p=0.020) were; the proximal neck length was not correlated with endoleaks if a proximal neck length >10 mm can be secured. Conclusion: Risks for early type I endoleaks after TEVAR for aneurysm were landing zone 0–2, LSA coverage, large proximal neck and stent-graft diameters, excessive oversizing, and the use of the chimney technique.

Impact of Oversizing on the Risk of Retrograde Dissection After TEVAR for Acute and Chronic Type B Dissection

Purpose: To find a suitable rate of thoracic stent-graft oversizing by exploring its association with the occurrence of retrograde type A dissection (RTAD) after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection. Methods: From January 2013 to June 2014, 203 patients (mean age 55 years; 167 men) with type B aortic dissection underwent TEVAR. The mean rate of oversizing at the proximal landing zone was 10% (range 0%–32%). Patients were stratified into 2 groups based on the degree of oversizing: ≤5% (n=105, mean 1.2%±1.5%) and >5% (n=98, mean 18.5%±2.8%). TEVAR-related complications, including RTAD, stent migration, and type I endoleaks, were analyzed. Results: There were no significant differences in the preoperative proximal landing zone diameters between the groups (31.1 mm for the ≤5% group vs 31.8 mm for the >5% group, p=0.229). The incidence of type I endoleaks over a mean follow-up 15.1±6.4 months was 5.4% [6 (5.7%) in the ≤5% group vs 5 (5.1%) in the >5% group, p=0.847]. The stent migration rate was low in both groups (1% vs 2%, respectively; p=0.521). The occurrence of RTAD [0 in the ≤5% group vs 11 (11.2%) in the >5% group] was significantly associated with the rate of oversizing (p<0.001). Conclusion: The early and midterm outcomes of this study demonstrate that ≤5% oversizing may be a suitable option for thoracic endografts used to treat type B dissection. The smaller rate of oversizing can lower the incidence of RTAD without increasing stent migration or type I endoleak rates.

Initial clinical experience with the Zenith alpha stent-graft

PURPOSE

To assess safety and short-term efficacy of endovascular repair of the thoracic aorta with the new Zenith Alpha stent-graft.

METHODS

Between August 2010 and May 2014, 33 patients (21 men; mean age 73.2±9.0 years) were treated Zenith Alpha stent-graft (group ZA). Outcomes of this group were compared with those of 34 patients (25 men; mean age 70.3±8.5 years) treated contemporaneously with the Zenith TX-2 for the same pathologies (group TX). The primary outcome measure was technical success. Data on iliac tortuosity, minimum access vessel diameter, and previous unsuccessful treatment with other endografts was also recorded.

RESULTS

Technical success was 93.9% in group ZA and 91.2% in group TX (p=0.67). There was no case of surgical death or conversion to open repair in either group. Two (6%) type I endoleaks occurred in group ZA and 3 (9%) in group TX (p=0.67). Three patients died within 30 days in group ZA vs. none in group TX (p=0.07). Mean minimum access vessel diameter was significantly smaller (5.07 vs. 6.65 mm, p=0.002) and iliac tortuosity indices significantly higher in group ZA (1.34 vs. 1.25, p=0.02). Access vessel complications occurred in 1 (3%) patient in group ZA and 4 (12%) patients in group TX (p=0.17). Significantly more patients in group ZA (6, 18%) were unsuccessfully treated previously with other endografts vs. none in group TX (p=0.01).

CONCLUSION

The new Zenith Alpha appears to be equally as safe and efficacious as the Zenith TX-2 while being used in patients with demanding access vessel morphology.

Preoperative morphology influences thoracic aortic aneurysm sac expansion after endovascular repair

Background

The fate of the aneurysm sac after thoracic endovascular aortic repair (TEVAR) remains poorly defined. The aim of this study was to characterize the incidence of aneurysm sac expansion after TEVAR, and to determine the effect of aneurysm morphology on postoperative sac behaviour.

Methods

Preoperative and postoperative CT angiography (CTA) images were analysed from a proprietary database (M2S). TEVARs undertaken for thoracic aortic aneurysms from 2004 to 2013 were included. Preoperative aortic morphology was available for each patient. Post-TEVAR sac expansion was defined as an increase in aortic diameter of at least 5 mm. The influence of aortic morphological variables on sac expansion was assessed using Cox regression and Kaplan–Meier analysis.

Results

CTA images were available for 899 patients who underwent TEVAR. Median follow-up was 2·1 (i.q.r. 1·7–2·4) years. Some 46·0 per cent had a maximum aneurysm diameter of 55 mm or more at the time of repair. The 5-year rate of freedom from sac expansion of at least 5 mm was 60·9 per cent. The sac expansion rate after 3 years was higher when the proximal sealing zone was over 38 mm in diameter (freedom from expansion 51·2 per cent versus 76·6 per cent for diameter 38 mm or less; P &lt; 0·001), or 20 mm or less in length (freedom from expansion 67·3 per cent versus 77·1 per cent for length exceeding 20 mm; P = 0·022). Findings for the distal sealing zone were similar. The risk of sac expansion increased according to the number of adverse morphological risk factors (freedom from expansion rate 79·1 per cent at 3 years in patients with 2 or fewer risk factors versus 45·7 per cent in those with more than 2; P &lt; 0·001).

Conclusion

Sac expansion was common in this cohort of patients undergoing TEVAR for thoracic aortic aneurysm. Aneurysm sac expansion was significantly influenced by adverse morphological features in the aortic stent-graft sealing zones.

Multivariate Analysis of Risk Factors of Cerebral Infarction in 439 Patients Undergoing Thoracic Endovascular Aneurysm Repair

The aim of the study is to identify the potential risk factors of cerebral infarction associated with thoracic endovascular aneurysm repair (TEVAR). TEVAR was developed as a less invasive surgical alternative to conventional open repair for thoracic aortic aneurysm treatment. However, outcomes following TEVAR of aortic and distal arch aneurysms remain suboptimal. Cerebral infarction is a major concern during the perioperative period. We included 439 patients who underwent TEVAR of aortic aneurysms at a high-volume teaching hospital between July 2006 and June 2013. Univariate and multivariate logistic regression analyses were performed to identify perioperative cerebral infarction risk factors. Four patients (0.9%) died within 30 days of TEVAR; 17 (3.9%) developed cerebral infarction. In univariate analysis, history of ischemic heart disease and cerebral infarction and concomitant cerebrovascular disease were significantly associated with cerebral infarction. "Shaggy aorta" presence, left subclavian artery coverage, carotid artery debranching, and pull-through wire use were identified as independent risk factors of cerebral infarction. In multivariate analysis, history of ischemic heart disease (odds ratio [OR] 6.49, P = 0.046) and cerebral infarction (OR 43.74, P = 0.031), "shaggy aorta" (OR 30.32, P < 0.001), pull-through wire use during surgery (OR 7.196, P = 0.014), and intraoperative blood loss ≥800 mL (OR 24.31, P = 0.017) were found to be independent risk factors of cerebral infarction. This study identified patient- and procedure-related risk factors of cerebral infarction following TEVAR. These results indicate that patient outcomes could be improved through the identification and management of procedure-related risk factors.

Carbon Dioxide Flushing Technique to Prevent Cerebral Arterial Air Embolism and Stroke During TEVAR

Purpose: To describe the technique of carbon dioxide (CO2) flushing of thoracic stent-grafts to reduce the risk of cerebral air embolism. Technique: To remove room air, thoracic stent-grafts were preoperatively flushed 2 minutes with carbon dioxide from a cylinder connected to the flushing chamber of the captor valves of Zenith custom-made endografts; this was followed by the standard saline flush. Thirty-six patients undergoing thoracic endovascular aortic repairs (TEVAR) involving the ascending aorta and the aortic arch received CO2-flushed Zenith endografts. One patient with a highly calcified arch experienced a minor stroke. Conclusion: Arterial air embolism is a potentially underappreciated problem of aortic endografting, especially in the proximal segments of the aorta. CO2 flushing may have the potential to reduce air embolization during TEVAR.

Update on the use of abdominal and thoracic endografts for treating aortic aneurysms

Endovascular abdominal and thoracic aneurysm repair has heralded a paradigm shift in the management of abdominal and thoracic aortic aneurysms. Randomized controlled trials have suggested superior short-term and equivalent long-term outcomes of endovascular repair compared with open surgery. Existing endografts have undergone several modifications to meet anatomic challenges and improve patient results. In the past, endovascular repair has been limited to infrarenal abdominal aortic aneurysms and isolated thoracic aortic aneurysms. The advent of fenestrated and branched endografts have made endovascular repair of thoracoabdominal and juxtarenal aneurysms possible. Continued evolution of endograft technology will maximize the benefit and minimize complications in patients with a range of aneurysmal disease.

Occupational Radiation Exposure During Endovascular Aortic Repair

PURPOSE

The aim of the study was to evaluate the radiation exposure to operating room personnel and to assess determinants for high personal doses during endovascular aortic repair.

MATERIALS AND METHODS

Occupational radiation exposure was prospectively evaluated during 22 infra-renal aortic repair procedures (EVAR), 11 thoracic aortic repair procedures (TEVAR), and 11 fenestrated or branched aortic repair procedures (FEVAR). Real-time over-lead dosimeters attached to the left breast pocket measured personal doses for the first operators (FO) and second operators (SO), radiology technicians (RT), scrub nurses (SN), anesthesiologists (AN), and non-sterile nurses (NSN). Besides protective apron and thyroid collar, no additional radiation shielding was used. Procedural dose area product (DAP), iodinated contrast volume, fluoroscopy time, patient's body weight, and C-arm angulation were documented.

RESULTS

Average procedural FO dose was significantly higher during FEVAR (0.34 ± 0.28 mSv) compared to EVAR (0.11 ± 0.21 mSv) and TEVAR (0.06 ± 0.05 mSv; p = 0.003). Average personnel doses were 0.17 ± 0.21 mSv (FO), 0.042 ± 0.045 mSv (SO), 0.019 ± 0.042 mSv (RT), 0.017 ± 0.031 mSv (SN), 0.006 ± 0.007 mSv (AN), and 0.004 ± 0.009 mSv (NSN). SO and AN doses were strongly correlated with FO dose (p = 0.003 and p < 0.001). There was a significant correlation between FO dose and procedural DAP (R = 0.69, p < 0.001), iodinated contrast volume (R = 0.67, p < 0.001) and left-anterior C-arm projections >60° (p = 0.02), and a weak correlation with fluoroscopy time (R = 0.40, p = 0.049).

CONCLUSION

Average FO dose was a factor four higher than SO dose. Predictors for high personal doses are procedural DAP, iodinated contrast volume, and left-anterior C-arm projections greater than 60°.