Midterm results of endovascular abdominal aortic aneurysm repair: comparison of instruction-for-use (IFU) cases and non-IFU cases

Purpose

To investigate the midterm results of abdominal aortic aneurysm repair (EVAR) and compare the endoleak (EL) and abdominal aortic aneurysm (AAA) prognoses between instruction-for-use (IFU) patients and non-IFU patients.

Materials and methods

Of 124 patients (104 men, 20 women; mean age 76.2 years; age range 58–93 years) with AAA who underwent EVAR with the Zenith (68 patients) or Excluder device (56) and were analyzed, 86 were IFU and 38 non-IFU.

Results

The mean absorbed dose of radiation exposure was 1907 mGy in the IFU group and 2283 mGy in the non-IFU group (p = 0.013). Thirty-five patients experienced EL: 8 (6.5 %) type I and 27 (21.8 %) type II. Type I ELs were observed in 3 patients in the IFU group (3.5 %) and 5 patients in the non-IFU group (13.2 %). Of the 14 patients with AAA diameter expansion of ≥5 mm, 6 (6/86, 7.0 %) belonged to the IFU group and 8 (8/38, 21.1 %) to the non-IFU group (p = 0.027).

Conclusion

The frequency of AAA expansion ≥5 mm was higher in non-IFU patients than in IFU patients. Therefore, careful follow-up is necessary for non-IFU patients rather than IFU patients.     

Changes in inflammatory,coagulopathic, and fibrinolytic responses after endovascular repair of an abdominal aortic aneurysm: relationship between fibrinogen degradation product levels and endoleaks

Purpose

To compare the inflammatory, coagulopathic, and fibrinolytic responses after endovascular aneurysm repair (EVAR) of an abdominal aortic aneurysm between two stent grafts. Fibrinogen degradation product (FDP) levels were compared between patients with or without an endoleak.

Materials and methods

EVAR was performed in 88 patients using an Excluder (37 patients) or a Zenith (51 patients). White blood cell count (WBC), C-reactive protein (CRP) levels, platelet count, and FDP levels were measured before and after EVAR.

Results

WBC and CRP increased and the platelet count decreased significantly on days 1 and 3 after EVAR in the Zenith group compared with the Excluder group. The change in FDP from baseline to 7 days after EVAR was ?1.99 ± 7.46 vs. 8.59 ± 9.38 μg/mL in patients with (n = 24) vs. without (n = 64) an endoleak (p < 0.001). A change in FDP of 3.1 μg/mL was the optimal cutoff point for predicting the presence of an endoleak (accuracy 0.762; sensitivity 0.875; specificity 0.717).

Conclusion

Inflammatory, coagulopathic, and fibrinolytic responses were greater in the Zenith group than in the Excluder group. A change in FDP of ≤3.1 μg/mL was predictive of an endoleak after EVAR.     

Low baseline and subsequent higher aortic abdominal aneurysm FDG uptake are associated with poor sac shrinkage post endovascular repair

Purpose

The growth phases of medically treated abdominal aortic aneurysms (AAA) are frequently associated with an ¹⁸F–fluorodesoxyglucose positron emission tomography (FDG-PET) pattern involving low baseline and subsequent higher FDG uptake. However, the FDG-PET patterns associated with the endovascular aneurysm repair (EVAR) of larger AAA are presently unknown. This study aimed to investigate the relationship between serial AAA FDG uptake measurements, obtained before EVAR and 1 and 6 months post-intervention and subsequent sac shrinkage at 6 months, a well-recognized indicator of successful repair.

Methods

Thirty-three AAA patients referred for EVAR (maximal diameter: 55.4?±?6.0 mm, total volume: 205.7?±?63.0 mL) underwent FDG-PET/computed tomography (CT) before EVAR and at 1 and 6 months thereafter, with the monitoring of AAA volume and of a maximal standardized FDG uptake [SUVmax] averaged between the axial slices encompassing the AAA.

Results

Sac shrinkage was highly variable and could be stratified into three terciles: a first tercile in which shrinkage was absent or very limited (0–29 mL) and a third tercile with pronounced shrinkage (56–165 mL). SUVmax values were relatively low at baseline in the 1st tercile (SUVmax: 1.69?±?0.33), but markedly increased at 6 months (2.42?±?0.69, p?=?0.02 vs. baseline). These SUV max values were by contrast much higher at baseline in the 3rd tercile (SUVmax: 2.53?±?0.83 p?=?0.009 vs. 1st tercile) and stable at 6 months (2.49?±?0.80), while intermediate results were documented in the 2nd tercile. Lastly, the amount of sac shrinkage, expressed in absolute values or in percentages of baseline AAA volumes, was positively correlated with baseline SUVmax (p?=?0.001 for both).

Conclusion

A low pre-EVAR FDG uptake and increased AAA FDG uptake at 6 months are associated with reduced sac shrinkage. This sequential FDG-PET pattern is similar to that already shown to accompany growth phases of medically treated AAA.

     

Clinical significance of endoleaks characterized by computed tomography during aortography performed immediately after endovascular abdominal aortic aneurysm repair: prediction of persistent endoleak

Purpose

This study aimed to predict the persistence of endoleaks (ELs) using patterns and volumes evaluated by computed tomography during aortography (CTDA) performed immediately after endovascular abdominal aortic aneurysm repair (EVAR).

Materials and methods

CTDA immediately after EVAR and at the 6-month follow-up CT were performed in 52 patients. ELs were classified as localized-type pattern (LTP; <180° around the center of the aneurysmal lumen) or circumferential-type pattern (CTP; >180°). The proportion of EL volume in the aneurysmal sac, excluding mural thrombus, was classified as grade A (≤5 %), B (5–10 %), or C (≥10 %). The 6-month follow-up residual rates were evaluated, and volume ratios (follow-up CT aneurysmal volume including mural thrombus/CTDA aneurysmal volume) were calculated.

Results

The residual rate (5.3 %) and mean volume ratio (83.9 %) of ELs with LTP were significantly lower than those of ELs with CTP (72.2 and 99.3 %, respectively); there was no significant difference in residual rate or mean volume ratio among EL grades (A: 17.6, 88.1 %; B: 55.6, 89.7 %; C: 54.5, 97.8 %).

Conclusion

ELs with LTP generally disappear over time after EVAR, with a concomitant reduction in aneurysm volume, whereas those with CTP persist, indicating that patients with EL with a CTP should be followed up carefully.     

Impact of contrast injection and stent-graft implantation on reproducibility of volume measurements in semiautomated segmentation of abdominal aortic aneurysm on computed tomography

Purpose

To assess the impact of contrast injection and stent-graft implantation on feasibility, accuracy, and reproducibility of abdominal aortic aneurysm (AAA) volume and maximal diameter (D-max) measurements using segmentation software.

Materials and methods

CT images of 80 subjects presenting AAA were divided into four equal groups: with or without contrast enhancement, and with or without stent-graft implantation. Semiautomated software was used to segment the aortic wall, once by an expert and twice by three readers. Volume and D-max reproducibility was estimated by intraclass correlation coefficients (ICC), and accuracy was estimated between the expert and the readers by mean relative errors.

Results

All segmentations were technically successful. The mean AAA volume was 167.0?±?82.8 mL and the mean D-max 55.0?±?10.6 mm. Inter- and intraobserver ICCs for volume and D-max measurements were greater than 0.99. Mean relative errors between readers varied between ?1.8?±?4.6 and 0.0?±?3.6 mL. Mean relative errors in volume and D-max measurements between readers showed no significant difference between the four groups (P?≥?0.2).

Conclusion

The feasibility, accuracy, and reproducibility of AAA volume and D-max measurements using segmentation software were not affected by the absence of contrast injection or the presence of stent-graft.

Key points

? AAA volumetry by semiautomated segmentation is accurate on CT following endovascular repair. ? AAA volumetry by semiautomated segmentation is accurate on unenhanced CT. ? Standardization of the segmentation technique maximizes the reproducibility of volume measurements.     

The Influence of Preoperative Aneurysmal Thrombus Quantity and Distribution on the Development of Type II Endoleaks with Aneurysm Sac Enlargement After EVAR of AAA

Purpose

To determine the influence of preoperative aneurysmal thrombus quantity and distribution on the development of type II endoleak with aneurysm sac enlargement after endovascular aneurysm repair (EVAR).

Materials and Methods

We retrospectively analyzed the pre- and postoperatively performed CT scans of 118 patients who had follow-up imaging for at least 1 year after EVAR available. We assessed preoperative thrombus perimeter (T _Peri), diameter (T _Dia), cross-sectional area (T _CSA), and volume (T _Vol). The preoperative thrombus distribution was classified into no thrombus, semilunar-shaped (anterior, right side, left side, posterior) thrombus, and circumferential type thrombus. The number of preoperative patent aortic side branches (ASB) was identified. Endpoint was type II endoleak with aneurysm volume (A _Vol) increase of ≥5 % during follow-up.

Results

During follow-up (2 years, range 1–9 years), 17 patients with type II endoleak had significant A _Vol increase. Less preoperative T _Peri, T _Dia, T _CSA, and T _Vol were associated with A _Vol increase. A circumferential thrombus distribution significantly protected against aneurysm enlargement (p = 0.028). The variables with the strongest significance for A _Vol increase were preoperative T _Vol/A _Vol ratio (OR 0.95; p = 0.037) and number of patent ASB (OR 3.52; p < 0.001).

Conclusion

A low preoperative T _Vol/A _Vol ratio and a high number of patent ASB were associated with aneurysm sac enlargement after EVAR.

     

Systolic Sac Pressure Index for the Prediction of Persistent Type II Endoleak for 12 Months After Endovascular Abdominal Aortic Aneurysm Repair

Purpose

To assess the relationship between the systolic sac pressure index (SPI) and the presence of endoleaks 12 months after endovascular abdominal aortic aneurysm repair (EVAR).

Materials and Methods

We performed a single-center prospective trial of consecutively treated patients. SPI (calculated as systolic sac pressure/systolic aortic pressure) was measured by catheterization immediately after EVAR. Contrast-enhanced computed tomography was scheduled 12 months after EVAR to detect possible endoleaks.

Results

Data were available for 34 patients who underwent EVAR for an AAA. Persisting type II endoleak was found in 8 patients (endoleak-positive group) but not in the other 26 patients (endoleak-negative group). The mean ± standard deviation SPI was significantly greater in the endoleak-positive group than in the endoleak-negative group (0.692 ± 0.048 vs. 0.505 ± 0.081, respectively; P = .001). Receiver-operating characteristic curve analysis revealed that an SPI of 0.638 was the optimum cutoff value for predicting a persistent endoleak at 12 months with high accuracy (0.971; 33/34), sensitivity (1.00), and specificity (0.962) values. The mean change in AAA diameter was ?4.28 ± 5.03 mm and 2.22 ± 4.54 mm in patients with SPI of <0.638 or ≥0.638, respectively (P = .002).

Conclusion

Patients with an SPI of ≥0.638 immediately after EVAR were more likely to have a persistent type II endoleak at 12 months with an accuracy of 0.971, and showed increases in aneurysm sac diameter compared with patients with an SPI of <0.638.

     

Morphological State as a Predictor for Reintervention and Mortality After EVAR for AAA

Purpose

This study was designed to assess aorto-iliac morphological characteristics in relation to reintervention and all-cause long-term mortality in patients undergoing standard EVAR for infrarenal AAA.

Methods

Patients treated with EVAR (Zenith^? Stentgrafts, Cook) between May 1998 and February 2006 were prospectively enrolled in a computerized database where comorbidities and preoperative aneurysm morphology were entered. Reinterventions and mortality were checked until December 1, 2010. Median follow-up time was 68?months.

Results

A total of 304 patients were included, of which 86% were men. Median age was 74?years. The reintervention rate was 23.4% (71/304). A greater diameter of the common iliac artery (p?=?0.037; hazard ratio (HR) 1.037 [1.002–1.073]) was an independent factor for an increased number of reinterventions. The 30-day mortality rate was 3.0% (9/304). Aneurysm-related deaths due to AAA occurred in 4.9% (15/304). Five patients died due to a concomitant ruptured thoracic aortic aneurysm. The mortality until end of follow-up was 54.3% (165/304). The proportion of deaths caused by vascular diseases was 61.6%. The severity of angulation of the iliac arteries (p?=?0.014; HR 1.018 [95% confidence interval (CI) 1.004–1.033]) and anemia (p?=?0.044; HR 2.79 [95% CI 1.029–7.556]) remained as independent factors associated with all-cause long-term mortality. The crude reintervention-free survival rate at 1, 3, and 5?years was 84.5%, 64.8%, and 51.6%, respectively.

Conclusions

The initial aorto-iliac morphological state in patients scheduled for standard EVAR for AAA seems to be strongly related to the need for reinterventions and long-term mortality.     

Dual-energy computed tomography after endovascular aortic aneurysm repair: The role of hard plaque imaging for endoleak detection

Objectives

To assess the diagnostic accuracy of dual-energy computed tomography (DECT) for detection of endoleaks and aneurysm sac calcifications after endovascular aneurysm repair (EVAR) using hard plaque imaging algorithms.

Materials and methods

One hundred five patients received 108 triple-phase contrast-enhanced CT (non-contrast, arterial and delayed phase) after EVAR. The delayed phase was acquired in dual-energy and post-processed using the standard (HPI-S) and a modified (HPI-M) hard plaque imaging algorithm. The reference standard was determined using the triple-phase CT and contrast-enhanced ultrasound. All images were analysed separately for the presence of endoleaks and calcifications by two independent readers; sensitivity, specificity and interobserver agreement were calculated.

Results

Endoleaks and calcifications were present in 25.9 % (28/108) and 20.4 % (22/108) of images. The HPI-S images had a sensitivity/specificity of 54 %/100 % (reader 1) and 57 %/99 % (reader 2), the HPI-M images of 93 %/92 % (reader 1) and 96 %/92 % (reader 2) for detection of endoleaks. For detection of calcifications HPI-S had a sensitivity/specificity of 91 %/99 % (reader 1) and 95 %/97 % (reader 2), the HPI-M images of 91 %/99 % (reader 1) and 91 %/99 % (reader 2), respectively.

Conclusion

Using HPI-M, DECT enables an accurate diagnosis of endoleaks after EVAR and allows distinguishing between endoleaks and calcifications with high diagnostic accuracy.

Key Points

? Dual-energy computed tomography allows the diagnosis of aortic pathologies after EVAR. ? Hard plaque imaging algorithms can distinguish between endoleaks and aneurysm sac calcifications. ? The modified hard plaque imaging algorithm detects endoleaks with high diagnostic accuracy.     

Volumetric analysis of the aneurysmal sac with computed tomography in the follow-up of abdominal aortic aneurysms after endovascular treatment

Purpose

Our aim was to assess the usefulness of volumetric analysis for the follow-up of abdominal aortic aneurysms after endovascular repair (EVAR) and operator independence of the method.

Materials and methods

We retrospectively evaluated 99 computed tomography (CT) exams of 33 patients. Two blinded operators assessed the volume before treatment and after EVAR at 1?C3 and 12?C24 months. Friedman??s statistical test was used to assess the reproducibility of the method. The time required for postprocessing by the two operators was compared.

Results

One patient was excluded. Twenty-one patients showed no endoleak: 12/21 showed a volume reduction at both follow-up scans (9.7% and 19.5%, respectively); 8/21 showed an early volume increase (9.8%) with a late reduction (10.5%); 1/21 patient showed a volume increase at both follow-up scans (endotension). Eleven patients had an endoleak (one type I, nine type II and one type III); 4/9 type II endoleaks showed a volume reduction at both post-EVAR scans (8.5% and 19.5%). All other cases showed a volume increase after EVAR (type II 15.4%/16.8%, type I 24.1%/9.1%, type III 8%/10.7%). The Friedman statistical test assessed operator independence with p < 0.001. Mean difference between the two operators was 0.9% (0?C4.3%).

Conclusions

CT volume analysis is an accurate and reproducible modality for the follow-up of abdominal aortic aneurysms after EVAR. At early follow-up, contrast-enhanced CT remains mandatory to identify small endoleaks. For later follow-up, volumetric analysis would eliminate the need for contrast material in asymptomatic patients with stable or decreasing aneurysm volume.     

Renal dysfunction after abdominal or thoracic endovascular aortic aneurysm repair: incidence and risk factors

Purpose

To determine the incidence and risk factors of renal dysfunction after abdominal endovascular aortic repair (EVAR) and thoracic endovascular aortic repair (TEVAR).

Materials and methods

The study consisted of 227 patients treated with EVAR and 90 with TEVAR for aortic aneurysms. Parameters, including patients’ background factors, preoperative renal function, contrast dose and aortic wall irregularity on CT images were assessed in relation to postoperative renal dysfunction.

Results

Deterioration of renal function was observed in 33 of 218 patients (15.1%) after EVAR and in 7 of 79 (8.9%) patients after TEVAR. Hemodialysis was required in one patient after EVAR. In EVAR, renal dysfunction correlated with age (p = 0.034) and occlusion of accessory renal artery (p = 0.0001). In TEVAR, renal dysfunction correlated with age (p = 0.021), contrast dose (p = 0.042) and irregularity of the descending aortic wall (p = 0.023). In a multiple regression analysis, postoperative renal dysfunction was correlated with occlusion of accessory renal artery (p = 0.0003) after EVAR, and age (p = 0.02), contrast dose (p = 0.026) and irregularity of the descending aortic wall (p = 0.042) after TEVAR.

Conclusion

Occlusion of accessory renal artery in EVAR, and age, contrast dose and irregularity of the descending aortic wall in TEVAR were considered to be predictors of postoperative renal dysfunction.

     

Risk factors associated with late aneurysmal sac expansion after endovascular abdominal aortic aneurysm repair

PURPOSE

We aimed to identify the risk factors associated with late aneurysmal sac expansion after endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

We retrospectively reviewed contrast-enhanced computed tomography (CT) images of 143 patients who were followed for ≥6 months after EVAR. Sac expansion was defined as an increase in sac diameter of 5 mm relative to the preoperative diameter. Univariate and multivariate analyses were performed to identify associated risk factors for late sac expansion after EVAR from the following variables: age, gender, device, endoleak, antiplatelet therapy, internal iliac artery embolization, and preprocedural variables (aneurysm diameter, proximal neck diameter, proximal neck length, suprarenal neck angulation, and infrarenal neck angulation).

RESULTS

Univariate analysis revealed female gender, endoleak, aneurysm diameter ≥60 mm, suprarenal neck angulation >45°, and infrarenal neck angulation >60° as factors associated with sac expansion. Multivariate analysis revealed endoleak, aneurysm diameter ≥60 mm, and infrarenal neck angulation >60° as independent predictors of sac expansion (P < 0.05, for all).

CONCLUSION

Our results suggest that patients with small abdominal aortic aneurysms (<60 mm) and infrarenal neck angulation ≤60° are more favorable candidates for EVAR. Intraprocedural treatments, such as prophylactic embolization of aortic branches or intrasac embolization, may reduce the risk of sac expansion in patients with larger abdominal aortic aneurysms or greater infrarenal neck angulation.The aim of endovascular abdominal aortic aneurysm repair (EVAR) is to prevent rupture of an abdominal aortic aneurysm (AAA) by depressurizing the aneurysm and excluding it from the systemic circulation using a stent-graft. Aneurysmal sac reduction is a reliable marker for the long-term prognosis after EVAR. Although most aneurysmal sacs shrink after EVAR, some sacs continue to expand. A relationship between aneurysm size and endoleaks was previously reported (1, 2). Most type II endoleaks spontaneously disappear over time, but 10%–25% persist for more than six months after EVAR (3–6). Persistent endoleaks with aneurysmal sac expansion are at high risk of rupture because of the continuously elevated intra-aneurysmal pressure and require a second intervention, such as embolization (7–11). However, it is difficult to predict sac expansion and persistent endoleak before performing EVAR. Although intraoperative intrasac thrombin injection and prophylactic embolization of aortic branches such as the inferior mesenteric artery and lumbar artery are reported to reduce the incidence of type II endoleak, the efficacy and clinical benefit of these procedures in terms of late postoperative aneurysm shrinkage have not been fully evaluated (12–15). Therefore, the purpose of this study was to identify the risk factors associated with late aneurysmal sac expansion after EVAR to determine possible indications for intrasac embolization and prophylactic embolization of aortic branches.     

Impact of aortic valve calcification severity and impaired left ventricular function on 3-year results of patients undergoing transcatheter aortic valve replacement

Objectives

To evaluate clinical pre-interventional predictors of 3-year outcome and mortality in high-risk patients with severe aortic valve stenosis treated with transcatheter aortic valve implantation (TAVI).

Methods

Among 367 patients included in the Aachen TAVI registry, 76 patients with baseline dual-source computed tomography (DSCT) for the quantification of aortic valve calcification (AVC) and a 3-year follow-up were identified.

Results

Survival at 30 days was 91 %, and it was 75 %, 66 % and 64 % at 1, 2 years and 3 years, respectively. Non-survivors at 3 years showed a significantly higher Agatston AVC score (2,854?±?1,651) than survivors (1,854?±?961, P?=?0.007). Multivariate analysis including age, logistic EuroScore, glomerular filtration rate, Agatston AVC score, ejection fraction?<?40 %, NYHA class, baseline medication, chronic lung disease and aortic regurgitation revealed that only the Agatston AVC score (P?=?0.03) and impaired left ventricular function (P?=?0.001) was significantly associated with mortality. Patients with Agatston AVC scores >2,000 had a significantly lower 3-year survival rate compared with patients with scores <2,000 (47 % vs 79 %, P?=?0.004).

Conclusions

In patients referred for TAVI, aortic valve calcification severity and impaired left ventricular function may serve as a predictor of long-term mortality. Therefore, AVC scores easily determined from pre-procedural CT datasets may be used for patient risk stratification.

Key Points

? Dual-source CT provides excellent valve delineation before transcatheter aortic valve implantation (TAVI). ? Aortic valve calcification assessed by cardiac CT predicts mortality in TAVI patients. ? Aortic valve calcification scores can help stratify high-risk patients for TAVI. ? Three-year results show good long-term outcome without evidence of structural valve deterioration.     

Quantification of aortic distensibility in abdominal aortic aneurysm using ECG-gated multi-detector computed tomography

Rationale and objectives

To detect distensibility changes that might be an indicator for an increased risk of rupture, cross-sectional area changes of abdominal aortic aneurysms (AAA) have been determined using ECG-gated CT.

Materials and methods

Distensibility measurements of the aorta were performed in 67 patients with AAA. Time-resolved images were acquired with a four detector-row CT system using a modified CT-angiography protocol. Pulsatility-related cross-sectional area changes were calculated above and at AAA level by semiautomatic segmentation; distensibility values were obtained using additional systemic blood pressure measurements. Values were compared for small Ø< 5 cm (n=44) and large Ø> 5 cm (n?=?23) aneurysms.

Results

The aorta could be segmented successfully in all patients. Upstream AAA distensibility D was significantly higher than at AAA level for both groups: means above AAA (at AAA) D _above = (1.3±0.8)·10^?5 Pa^?1 (D _AAA = (0.6±0.5)·10^?5 Pa^?1) t-test p_D<0.0001. Differences of the distensibility between smaller and larger aneurysms were not found to be significant.

Conclusion

Distensibility can be measured non-invasively with ECG-gated CT. The reduction of distensibility within aneurysms compared to normal proximal aorta is subtle; the lack of difference between both small and large aneurysms suggests that this reduction occurs early in the aneurysm's development. Hence, reduced distensibility might be a predictive parameter in patients with high risk of aortic disease.

     

The impact of radiological equipment on patient radiation exposure during endovascular aortic aneurysm repair

Objectives

To compare the patient radiation dose during endovascular aortic aneurysm repair (EVAR) using different types of radiological systems: a mobile fluoroscopic C-arm, mobile angiographic and fixed angiographic equipment.

Methods

Dose–area products (DAP) were obtained from a retrospective study of 147 consecutive patients, subjected to 153 EVAR procedures during a 3.5-year period. On the basis of these data, entrance surface dose (ESD) and effective dose (ED) were calculated. EVARs were performed using a fluoroscopic C-arm, mobile or fixed angiographic equipment in 79, 26 and 48 procedures, respectively.

Results

Fluoroscopy times were essentially equivalent for all the systems, ranging from 15 to 19?min. The clinical outcomes were not significantly different among the systems. Statistically significant differences among radiological equipment grouping were found for DAP (mobile C-arm: 32?±?20?Gy?cm²; mobile angiography: 362?±?164?Gy?cm²; fixed angiography: 464?±?274?Gy?cm²; P?<?10^?6), for ESD (mobile C-arm: 0.18?±?0.11?Gy; mobile angiography: 2.0?±?0.8?Gy; fixed angiography: 2.5?±?1.5?Gy; P?<?10^?6) and ED (mobile C-arm: 6.2?±?4.5?mSv; mobile angiography: 64?±?26?mSv; fixed angiography: 129?±?76?mSv; P?<?10^?6).

Conclusions

Radiation dose in EVAR is substantially less with a modern portable C-arm than with a fixed or mobile dedicated angiographic system.

Key Points

? Fluoroscopy during endovascular aortic aneurysm repair can impart a substantial radiation dose. ? Radiation doses during EVAR are higher when using mobile/fixed angiographic systems. ? Mobile C-arm fluoroscopy imparts a lower dose with an equivalent clinical outcome. ? Procedures need to be dose-optimised when using mobile/fixed angiographic systems.     

Multicenter European Registry for Patients with AAA Undergoing EVAR Evaluating the Performance of the 36-mm-Diameter Endurant Stent-Graft

Introduction

The use of and results with the Endurant stent-graft have been reported extensively. However, there has been little if any focus placed on performance and outcomes when a 36-mm-diameter device is used.

Methods

Data were collected and retrospectively analyzed on EVAR patients treated with a 36-mm-diameter Endurant device at 3 European academic vascular centers between 2007 and 2015. Primary endpoints were the absence of type Ia endoleak in the early and mid-term follow-up period, and aneurysm sac stabilization or shrinkage. Secondary endpoints were 30-day mortality, overall survival and secondary interventions. Subgroup analysis of outcomes in the on-label (ONL) versus off-label (OFL) device use cohorts was also performed.

Results

Seventy-three patients were included in the study. Mean follow-up was 30.1 ± 16.2 months. Mean aortic neck diameter was 29.5 ± 1.9. Primary technical success was achieved in 69 patients (94.5%). Five patients (6.8%) were found to have developed a type Ia endoleak, 3 during the first month, and the other 2 at 2 years. Overall EVAR-related mortality was 4.1% (n = 3). Subgroup analysis focused on the OFL cohort (n = 44) versus the ONL patients (n = 29). Two of the OFL patients (4.5%) had a type Ia endoleak, and 3 (10.3%) in the ONL group.

Conclusion

The use of the largest diameter Endurant stent-graft device emerges as a reasonable option for EVAR treatment of AAA featuring a large-diameter proximal neck. Assessment of a larger group of patients followed in the long term will be necessary for a more definitive statement on such strategy.

     

Follow-up of abdominal aortic aneurysm after endovascular aortic repair: comparison of volumetric and diametric measurement

Purpose

To determine the correlation of maximal diameter measurements with volumetric evaluation of size after endovascular aortic repair (EVAR) of abdominal aortic aneurysms (AAA) using computed tomography angiography (CTA) and to survey its applicability for clinical follow-up.

Materials and methods

73 consecutive patients (2 females, 71 males; age 38–84 years; mean age, 69.1 ± 8 years) with AAA were treated with percutaneous EVAR in a single institution. For follow-up, CTA was performed periodically after EVAR. Images were evaluated for maximal diameter in consensus by two experienced radiologists. Using OsirixTM, volumetric measurements were done by one radiologist, including the entire infrarenal abdominal aorta.

Results

In 73 patients 220 CTA examinations were performed after EVAR with a mean follow-up of 17.3 months (range, 1.8–42.7 months). The mean postinterventional volume of aneurysm was 165.63 ml ± 93.29 ml (range, 47.94–565.67 ml). The mean maximal postinterventional diameter was 5.91 ± 1.52 cm (range, 3.72–13.82 cm). At large over the entire observation period a slight, non-significant decrease of 1.6% (2.58 ml ± 69.05 ml, range 82.82–201.92 ml) in volumes and a 9.3% (mean 0.55 cm ± 1.22 cm, range 2.85–1.93 cm) in diameters were observed. For all examinations a high correlation of volume and diameter was calculated (r = 0.813–0.905; α < 0.01).

Conclusion

For follow-up of abdominal EVAR using CTA there is a high correlation between volumetric and diametric measurements of aneurysm. Based on a daily clinical routine setting, measurements of maximal diameters in cross sectional imaging of AAA after EVAR seems to be sufficient to exclude post interventional enlargement.     

Endovascular Treatment of Ruptured Abdominal Aortic Aneurysms: Is Now EVAR the First Choice of Treatment?

Objective

This study was designed to evaluate the effectiveness of endovascular treatment (EVAR) for ruptured abdominal aortic aneurysms (rAAAs).

Methods

Between September 2005 and December 2012, 44 patients with rAAA suitable for endovascular repair underwent emergency EVAR. We did not consider hemodynamic instability to be a contraindication for EVAR.

Results

Successful stent-graft deployment was achieved in 42 patients, whereas 2 required open surgical conversion. The overall 30-day mortality was 10 of 44 patients (5/34 in stable patients, 5/10 in unstable patients). Postoperative complications were observed in 7 of 44 patients (16 %): 5 patients developed abdominal compartment syndrome requiring decompressive laparotomy; 1 patient developed bowel ischemia; 1 patient had limb ischemia, and 1 had hemodynamic shock. Mean length of intensive care unit stay was 2.9 (range 2–8) days, and mean length of hospital stay was 8.6 (range 0–18) days. At a mean follow-up of 22.2 (range 1–84) months, the overall incidence of endoleak was 23.5 %: 1 type I and 7 type II endoleaks.

Conclusions

Our study demonstrates that EVAR of rAAA is associated with acceptable mortality and morbidity rates in dedicated centers.     

Thoracic type Ia endoleak: direct percutaneous coil embolization of the aortic arch at the blood entry site after TEVAR and double-chimney stent-grafts

Objectives

To introduce a novel percutaneous technique to stop blood entry at the lesser aortic arch curvature by coil embolisation in type Ia endoleak after TEVAR.

Methods

A 61-year-old Marfan patient presented with type Ia endoleak of the aortic arch and a growing aortic arch pseudoaneurysm after TEVAR. Multiple preceding operations and interventions made an endovascular approach unsuccessful. Direct percutaneous puncture of the aneurysmal sac would have cured the sign, but not the cause of blood entry at the lesser curvature of the aortic arch. Direct CT-guided percutaneous puncture of the blood entry site in the aortic arch with fluoroscopically guided coil embolisation using detachable extra-long coils was successfully performed.

Results

Three weeks after the intervention, the patient developed fever because of superinfection of the pseudoaneurysm. The blood cultures and CT-guided mediastinal aspirate were sterile. After intravenous administration of antibiotics, the fever disappeared and the patient recovered. Six-month follow-up showed permanent closure of the endoleak and a shrinking aneurysmal sac.

Conclusions

Direct percutaneous puncture of the aortic arch at the blood entry site of a thoracic type Ia endoleak after TEVAR and double-chimney stent-grafts with coil embolisation of the wedge-shaped space between the lesser aortic curvature and the stent-graft is possible.

Key Points

? Endoleaks after thoracic endovascular aortic repair are common in 15-30 %. ? Most endoleaks can be treated by endovascular means. ? Direct percutaneous endoleak repair is described as a bail-out option. ? Direct percutaneous aortic arch coil embolisation of type 1a endoleak is possible. ? Antibiotic prophylaxis should be administered case by case, considering individual risk factors.     

18F-FDG PET-CT uptake is a feature of both normal diameter and aneurysmal aortic wall and is not related to aneurysm size

Purpose

Aortic metabolic activity is suggested to correlate with presence and progression of aneurysmal disease, but has been inadequately studied. This study investigates the 2-[¹⁸F] fluoro-2-deoxy-D-glucose (¹⁸F-FDG) uptake in a population of infra-renal abdominal aortic aneurysms (AAA), compared to a matched non-aneurysmal control group.

Methods

The Positron Emission Tomography – Computed Tomography (PET/CT) database was searched for infra-renal AAA. Exclusion criteria were prior repair, vasculitis, and saccular/mycotic thoracic or thoraco-abdominal aneurysms. Matching of 159 non-aneurysmal (<3 cm diameter) controls from the same population was assessed. Infra-renal aortic wall FDG uptake was assessed using visual analysis; maximum standardized uptake value (SUV_max) and target to background mediastinal blood pool ratio (TBR) were documented. Predictors of FDG uptake (age, sex, aortic diameter, hypertension, statin use, and diabetes) were assessed using univariate analysis. Follow-up questionnaires were sent to referring clinicians.

Results

Aneurysms (n?=?151) and controls (n?=?159) were matched (p?>?0.05) for age, sex, diabetes, hypertension, smoking status, statin use, and indication for PET/CT. Median aneurysm diameter was 5.0 cm (range 3.2–10.4). On visual analysis there was no significant difference in the overall numbers with increased visual uptake 24 % (36/151) in the aneurysm group vs. 19 % (30/159) in the controls, p?=?ns. SUV_max was slightly lower in the aneurysm group vs. controls (mean (2 SD) 1.75(0.79) vs. 1.84(0.58), p?=?0.02). However there was no difference in TBR between the AAA group and controls (mean (2 SD) 1.03 (0.46) vs. 1.05(0.31), p?=?0.36). During a median 18 (interquartile range 8–35) months’ follow-up 20 were repaired and four were confirmed ruptured.

Conclusions

The level of metabolic activity as assessed by ¹⁸F-FDG PET/CT in infra-renal AAA does not correlate with aortic size and does not differ between aneurysms and matched controls.