A systematic review and meta-analysis indicates underreporting of renal dysfunction following endovascular aneurysm repair

Safety, Effectiveness and Pitfalls of Carbon Dioxide Routine Use as a Contrast Agent for Endovascular Abdominal Aortic Repair

BACKGROUND

Despite the evidence of good performance, carbon dioxide (CO2) routine employment as a contrast agent for endovascular procedures is far from being adopted with its use currently limited to patients with renal impairment and known allergy to iodinated contrast medium (ICM). The purpose of our study is to evaluate the safety and effectiveness of CO2 guided endovascular abdominal aortic aneurysm repair (EVAR) in a standard population and to assess the rationale for a future widespread use.

METHODS

We retrospectively collected data of every patient who underwent CO2 guided standard EVAR from September 2020 to May 2021 and compared them with the data of every patient who underwent EVAR using ICM from December 2019 to August 2020 in our unit. The selection of the contrast medium was not based on any preoperative factor as the contrast medium was routinely used in every patient in both periods. The primary end point of the study was the technical success rate. Secondary end points were the early and late complication rates, radiation exposure and renal function impairment.

RESULTS

49 patients underwent ICM guided EVAR and 52 patients underwent CO2 guided EVAR in our unit in the time frames specified above. The technical success rate was 100% in both groups with no accidental coverage of any target vessel. Intraoperative endoleaks were observed in 14% of ICM patients and 25% of CO2 patients. The radiation exposure was higher in the CO2 group if compared to the ICM group (311.48 vs. 159.86 median mGy/cm2 - P < 0.001). The incidence of postoperative acute kidney injury was low and similar in the 2 groups. No significant worsening over time of the renal function has been reported in both groups.

CONCLUSIONS

EVAR can be safely performed under CO2 guidance without the integration of any quantity of ICM but with an increase in radiation exposure. The nephroprotective role of CO2 guided EVAR in a standard population is unclear and the same role in renal impaired patients should be validated with further studies on selected populations.

Intravascular Ultrasound Versus Computed Tomography Angiography in Sizing and Operative Management of Endovascular Aortic Aneurysm Repair

OBJECTIVES

An abdominal aortic aneurysm (AAA) is a potentially life-threatening condition, the management of which has dramatically evolved over the past 2 decades with an increasing tendency toward endovascular repair (EVAR) rather than open surgical repair. Classically, contrast-enhanced multislice computed tomography (CT) angiography (CTA) is performed preoperatively for procedure sizing and EVAR planning. This entails voluminous contrast injection with risk of allergic reaction, nephropathy, and radiation exposure. Intra-vascular ultrasound (IVUS) has been increasingly used to guide EVAR procedures intraoperatively. The aim of this study is to investigate the accuracy of IVUS in sizing AAAs, device selection, and EVAR planning compared to the gold standard CTA.

DESIGN

This is a prospective observational study enrolling 10 patients who underwent standard infrarenal EVAR procedures performed for unruptured infrarenal AAAs over the course of 1 year. All patients had a preoperative CTA done upon which aneurysm sizing and device planning were performed, and the measurements obtained were compared to those obtained from intraoperative IVUS.

METHODS

All participating patients had unruptured infrarenal AAA, had no renal impairment, and had anatomical suitability for EVAR according to the instructions for use (IFU) of the device manufacturer. Primary endpoint was comparing anatomical measurements recorded by IVUS with those obtained from the preoperative CTA.

RESULTS

Mean age was 65.6 (±6.19), all patients were males and hypertensives and 4 (40%) had a positive family history for AAA. On comparing mean measurements taken by CTA and IVUS, there was no statistically significant differences with exception of maximal aortic diameter and aortic diameter at site of bifurcation (both p-values <.001). There were no statistically significant differences in length measurements between the 2 imaging modalities. Computed tomography angiography was more associated with neck thrombus detection, and IVUS was more associated with calcification detection.

CONCLUSION

Although CT angiography is still the gold standard imaging modality for AAA, IVUS use is very beneficial in EVAR sizing and planning, in addition to intra-operative guidance of the procedure, saving the patient significant time, contrast administration, and radiation exposure, especially in patients with renal impairment and contrast allergy.

CLINICAL IMPACT

A preoperative CT angiogram is the gold standard required investigation for planning and sizing EVARs, with subsequent contrast injection entailing a risk of contrast induced nephropathy and allergic reactions. IVUS has been used as an adjuvant technique to guide EVAR stent graft deployment. However, our study concluded that it can also be reliably used in sizing and planning of the EVAR stent graft along with complementary non contrast imaging, especially in patients with high risk for contrast induced nephropathy and contrast allergy.

Efficacy of contrast-enhanced ultrasound in detection of type II endoleak after abdominal aortic aneurysm surgery: A prospective cohort study

PURPOSE

This study aimed to evaluate the efficacy of conventional contrast-enhanced ultrasound (CEUS) in detection of type II endoleak after endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

From January 2015 to April 2018, 205 patients underwent EVAR were included. CEUS and computed tomography angiography (CTA) were performed at 1-month follow-up postoperatively to detect type II endoleak. CEUS was performed at 3- and 6-month follow-up to evaluate the development of type II endoleak. The diameter extension of type II endoleak increased greater than 5 mm was defined as enlarge group, and that increased less than 5 mm was defined as stable group. The difference of arrival time (AT) of contrast agent, maximum cross-sectional area (MCSA) of contrast agent and the blood flow velocity (BFV) of the abnormal blood around the stent graft were compared.

RESULTS

At 1-month after EVAR, 65 cases of endoleak were detected by CEUS, including 25 cases of type I, 30 cases of type II endoleak and 10 cases of type III endoleak. Among them, 50 cases were also detected by CTA. The diameter extension of 12 cases of type II endoleak increased greater than 5 mm, and that of eight cases increased less than 5 mm. The average AT of the enlarge group was significantly shorter than that of the stable group, while the MCSA of contrast agent and the BFV were significantly higher than that of the stable group (p < 0.05).

CONCLUSION

CEUS has predictive value for the natural outcome of type II endoleak.

Three-dimensional Ultrasound Volume and Conventional Ultrasound Diameter Changes are Equally Good Markers of Endoleak in Follow-up after Endovascular Aneurysm Repair

INTRODUCTION

The main disadvantages of computed tomography angiography in follow-up after endovascular aneurysm repair are the risks of contrast-induced renal impairment and radiation-induced cancer. Three-dimensional ultrasound is a new technique for volume estimation of the aneurysm sac. Some studies have reported promising results. The aim of this study was to evaluate the accuracy and precision of three-dimensional ultrasound aneurysm sac-volume estimates, and to explore whether volume and/or diameter changes on ultrasound can be used as markers of endoleak.

METHODS

A single-center diagnostic accuracy study was performed. 92 Patients planned for endovascular aneurysm repair were prospectively and consecutively enrolled (2013-2016). Aneurysm sac diameter and volume were measured using computed tomography angiography, conventional ultrasound, and three-dimensional ultrasound preoperatively and 1, 6, 12, and 24 months postoperatively. Three-dimensional ultrasound was performed with a commercially available electromechanical transducer. Patients with endoleak were observed 5 years after endovascular aneurysm repair.

RESULTS

79 men and 13 women were included. Mean age was 74 years (57-92). Median follow-up was 24 months. Endoleak cases were observed for up to 55 months. Diameter measurements on conventional ultrasound correlated well with CT diameters (r = 0.9, P < 0.05, n = 347), and Bland-Altman analyses showed an upper limit of agreement of +0.5 cm and a lower limit of agreement of -0.8 cm. The mean difference was -0.13 cm ± 0.36 cm. Three-dimensional ultrasound volumes had a correlation with computed tomography angiography diameters of r = 0.8 (P < 0.05, n = 347) and with three-dimensional computed tomography volumes of r = 0.8 (P < 0.05, n = 155). Receiver operating characteristic analyses showed that the diameter and volume changes which led to reintervention were most accurate at 24-month follow-up, with area-under-the-curve percentage changes of 0.98 (two-dimensional ultrasound), 0.97 (three-dimensional ultrasound), and 0.97 (two-dimensional computed tomography).

DISCUSSION

Both diameter and volume changes can be used as markers for endoleak with excellent areas under the curve on receiver operating characteristic analyses. However, three-dimensional ultrasound volumes did not add any further diagnostic information. Conventional 2D diameter measurements were as accurate as volume changes as markers of endoleak.

CONCLUSION

Type II endoleaks can safely be followed up using a simple diameter measurement on conventional ultrasound.

A Simple Technique to Perform Endovascular Repair of Abdominal Aortic Aneurysms with a Very Low Dose of Iodine Contrast Media

Iodinated contrast media (ICM) dose is a major factor for postoperative acute kidney injury (AKI) in patients with severe chronic kidney disease (glomerular function rate [GFR] <30 mL/min) during endovascular aortic repair (EVAR). Fusion imaging in hybrid rooms and carbon dioxide angiography represent alternatives but are limited by significant cost and availability. We here describe a simple technique allowing EVAR with a limited ICM dose (<5 mL). Using a standard C-arm, the lowest renal artery and the hypogastric arteries are blindly catheterized based on noncontrast pre-operative imaging (duplex-scan associated with noncontrast computed tomography scan and/or magnetic resonance angiography). An injection of diluted ICM (1 mL ICM + 4 mL saline) can be performed to confirm the correct catheterisation and angiography catheters are let in place as landmarks. Ten patients with GFRs between 17 and 29 ml/min were successfully treated using these tips (median ICM = 3 mL) without postoperative AKI and satisfactory mid-term results.

Influence of baseline kidney dysfunction on perioperative renal outcomes after endovascular aneurysm repair with suprarenal fixation

BACKGROUND

Conflicting evidence exists regarding the comparative effects of endovascular aneurysm repair (EVAR) with and without suprarenal fixation. We compare outcomes in patients treated by EVAR with baseline normal kidney function and moderate and severe chronic kidney disease.

METHODS

Patients with normal kidney function (glomerular filtration rate [GFR] ≥60 mL/min/1.73 m²) or moderate (GFR = 30-59 mL/min/1.73 m²) or severe (GFR <30 mL/min/1.73 m²) kidney disease who underwent EVAR (N = 5534) were identified from the American College of Surgeons National Surgical Quality Improvement Program targeted database (2011-2015). Groups were determined by the presence (Cook Zenith [Cook Medical, Bloomington, Ind] or Medtronic Endurant [Medtronic, Minneapolis, Minn]) or absence (Gore Excluder [W. L. Gore & Associates, Flagstaff, Ariz]) of a suprarenal fixation system. Postoperative renal complications, defined as rise in creatinine concentration of >2 mg/dL without dialysis or new dialysis requirements, were analyzed within the first 30 days with results stratified by degree of kidney disease.

RESULTS

A total of 5534 patients underwent EVAR, with 3225 (58.3%) receiving a device using a suprarenal fixation system. Suprarenal fixation systems were less commonly used for symptomatic patients (11.0% vs 13.7%; P = .002) and patients with ruptured abdominal aortic aneurysm (4.5% vs 6.3%; P = .01). There was no difference in baseline kidney function between groups. EVAR with suprarenal fixation was associated with more renal complications (1.40% vs 0.65%; P = .008). In subgroup analysis, patients with moderate kidney dysfunction (n = 1780) had more renal complications (2.2% vs 0.8%; P = .02) with suprarenal fixation systems. No differences were seen in patients with normal kidney function (0.4% vs 0.2%; P = .32; n = 3597) or severe kidney dysfunction (14.3% vs 10.2%; P = .45; n = 157). This difference was driven mostly by postoperative elevation of creatinine concentration (0.6% vs 0.2%; P = .03) without requirements for new dialysis (0.8% vs 0.4%; P = .08). After adjustments with multivariate logistic regression models, EVAR with suprarenal fixation was associated with more renal complications (odds ratio, 2.65; 95% confidence interval, 1.32-5.34).

CONCLUSIONS

In our study, EVAR with suprarenal fixation devices was associated with more perioperative renal complications in patients with moderate kidney dysfunction. Long-term evaluation of these patients undergoing EVAR should be considered.

Renal Dysfunction Following Elective Endovascular Aortic Aneurysm Repair

Abdominal aortic aneurysm (AAA) is a degenerative disease of the aortic wall with potentially fatal complications. Open repair (OR) was considered the gold standard, until the emergence of endovascular aneurysm repair (EVAR), which is less invasive and equally (if not more) effective. As the popularity of endovascular procedures grows, related complications become more evident, with kidney damage being one of them. Although acute kidney injury (AKI) following EVAR is relatively common, its true incidence is still uncertain. Also, there is insufficient data concerning long-term renal outcomes after EVAR, especially with repeated contrast agent exposure. Despite the lack of firm evidence on the effectiveness of individual strategies, it is evident that prevention of AKI following EVAR requires a multifactorial approach. This review focuses on recent findings based on human studies regarding the current evidence of renal impairment after EVAR, its quantification and strategies for its prevention.

Acute Renal Failure/Acute Kidney Injury (AKI) Associated with Endovascular Procedures

AKI is one of the most common yet underdiagnosed postoperative complications that can occur after any type of surgery. Contrast-induced nephropathy (CIN) is still poorly defined and due to a wide range of confounding individual variables, its risk is difficult to determine. CIN mainly affects patients with underlying chronic kidney disease, diabetes, sepsis, heart failure, acute coronary syndrome and cardiogenic shock. Further research is necessary to better understand pathophysiology of contrast-induced AKI and consequent implementation of effective prevention and therapeutic strategies. Although many therapies have been tested to avoid CIN, the only potent preventative strategy involves aggressive fluid administration and reduction of contrast volume. Regardless of surgical technique—open or endovascular—perioperative AKI is associated with significant morbidity, mortality and cost. Endovascular procedures always require administration of a contrast media, which may cause acute tubular necrosis or renal vascular embolization leading to renal ischemia and as a consequence, contribute to increased number of post-operative AKIs.

Meta-analysis of Renal Function Following Infrarenal EVAR using Suprarenal or Infrarenal Fixation Devices

OBJECTIVE/BACKGROUND

The effect of suprarenal (SR) as opposed to infrarenal (IR) fixation on renal outcomes post-endovascular aneurysm repair (EVAR) remains controversial. This meta-analysis aims to update current understanding of this issue.

METHODS

A prior meta-analysis was updated through a Preferred Reporting Items for Systematic reviews and Meta-Analyses search for additional studies published in the last 3 years reporting on renal dysfunction or related outcomes post-EVAR. Random effects meta-analysis was undertaken using SPSS.

RESULTS

A total of 25 non-randomised studies comparing SR with IR fixation were included, totalling 54,832 patients. In total, 16,634 underwent SR and 38,198 IR. Baseline characteristics, including age, baseline estimated glomerular filtration rate, diabetes, cardiac disease, and smoking, were similar between the groups. There was a small but significant difference in outcomes for renal dysfunction at the study end point (SR 5.98% vs. IR 4.83%; odds ratio [OR] 1.29, 95% confidence interval [CI] 1.18-1.40 [p < .001]); however, at 30 days and 12 months there was no significant difference, and this did not hold up to sensitivity analysis. Incidence of renal infarcts (SR 6.6% vs. IR 2.3%; OR 2.78, 95% CI 1.46-5.29 [p = .002]), renal stenosis (SR 2.4% vs. IR 0.8%; OR 2.89, 95% CI 1.00-8.38 [p = .05]), and renal artery occlusion (SR 2.4% vs. IR 1.2%; OR 2.21, 95% CI 1.15-4.25 [p = 0.02]) favoured IR fixation; however, there was no difference in haemodialysis rates.

CONCLUSION

This meta-analysis has identified small but significantly worse renal outcomes in patients having SR fixation devices compared with IR; however, there was no difference in dialysis rates and a small effect on renal dysfunction, which did not stand up to rigorous sensitivity analysis. This should be taken into consideration during graft selection, and further studies must assess renal outcomes in the longer term, and in those with pre-existing renal dysfunction.

Determinants of Acute Kidney Injury and Renal Function Decline After Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVE/BACKGROUND

Endovascular aneurysm repair (EVAR) may be associated with renal injury and more insight is needed into potential risk factors. The aim was to identify clinical, anatomical, and peri-procedural parameters as potential risk factors for the occurrence of acute kidney injury (AKI) and to evaluate chronic kidney disease (CKD) after EVAR.

METHODS

A cohort of 212 consecutive patients who underwent elective EVAR for abdominal aortic aneurysm from January 2009 to October 2016 was included. A subgroup of 149 patients with 2 years follow-up was compared with a set of 135 non-operated aneurysm patients with smaller aneurysms (similar cardiovascular risk profile) to assess CKD. Primary outcomes were AKI (Acute Kidney Injury Network criteria) and CKD measured by estimated glomerular filtration rate (Kidney Disease Improving Global Outcomes guidelines). For AKI, candidate risk factors were identified by univariate and multivariate logistic regression analysis; for chronic renal function decline, risk factors were identified using Cox regression analysis.

RESULTS

AKI occurred in 30 patients (15%). On multivariate analysis, the use of angiotensin II blocker (odds ratio [OR] 4.08, 95% confidence interval [CI] 1.38-12.07) and peri-operative complications (OR 3.12, 95% CI 1.20-8.10) were independent risk factors for AKI, whereas statin use was a protective factor (OR 0.19, 95% CI 0.07-0.52). EVAR resulted in a significant increase (23.5%) in the occurrence of CKD compared with the control group (6.7%; p <.001). On univariate and multivariate Cox regression the risk factors: aortic neck diameter (per mm increase) (hazard ratio [HR] 1.13, 95% CI 1.02-1.25), renal artery stenosis >50% (HR 2.24, 95% CI 1.05-4.79), and the occurrence of AKI (HR 2.19, 95% CI 0.99-4.85) were significant predictors of CKD.

CONCLUSION

This study identified use of angiotensin II blockers and peri-operative complications as risk factors for AKI. In addition, the problem of renal function decline after EVAR is highlighted, which indicates that prolonged protective measures (e.g., in those patients at high risk) over time are needed to improve patient outcomes.

Evaluation of the renal function using serum Cystatin C following open and endovascular aortic aneurysm repair

Objectives

Controversies regarding renal function impairment after open and endovascular aortic aneurysm repair still exist. The purpose of this study was to evaluate the renal function following open repair and endovascular aneurysm repair using Cystatin C.

Methods

This prospective, observational case–control study was conducted in tertiary referral centre over 3 years, starting from 2012. In total, 60 patients operated due to infrarenal AAA either by means of open repair (30 patients) or endovascular aneurysm repair (30 patients) were included in the study. Biochemical markers of renal function (sCr, urea, potassium) were recorded pre-operatively and at these specific time points, immediately after the operation and at discharge, home (third postoperative day, endovascular aneurysm repair group) or from intensive care unit (third postoperative day, open repair group). Multivariate and propensity score adjustments were used to control for the baseline differences between the groups.

Results

Creatinine levels in serum remained unchanged during the hospital stay in both groups without significant differences at any time point. Cystatin C levels in endovascular aneurysm repair patients significantly increased postoperatively and restored to values comparable to baseline at the discharge (0.865 ± 0.319 vs. *0.962 ± 0.353 vs. 0.921 ± 0.322, * p < 0.001). Cystatin C levels in patients treated with the open surgery was decreasing over time but not statistically significant comparing to Cystatin C values at the admission. However, decrease in Cystatin C serum levels in patients treated with conventional surgery resulted in statistically significant lower values compared to endovascular aneurysm repair patients both postoperatively and at the time of discharge (0.760 ± 0.225 vs. 0.962 ± 0.353, p < 0.05; 0.750 vs. 0.156, p < 0.05). Both multivariate linear regression models and propensity score adjustment confirm that, even after correction for previously observed intergroup differences, type of surgery, i.e. endovascular aneurysm repair is independently associated with the higher levels of Cystatin C both postoperatively and at the discharge.

Conclusions

Dynamics of Cystatin C levels have been proven as a more vulnerable marker of renal dysfunction. Endovascular aneurysm repair is associated with higher levels of kidney injury markers.

Concurrent renal artery stent during endovascular infrarenal aortic aneurysm repair confers higher risk for 30-day acute renal failure

OBJECTIVE

Concurrent renal artery angioplasty and stenting (RAAS) during endovascular aneurysm repair (EVAR) of infrarenal abdominal aortic aneurysm (AAA) has been practiced in an attempt to maintain renal perfusion. The aim of this study was to identify the current practice of RAAS during EVAR and its effect on perioperative renal outcome.

METHODS

Patients with infrarenal AAA were identified from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP, 2011-2014) database. Baseline characteristics of patients with concurrent RAAS during EVAR were compared with those of patients who underwent EVAR only. Bivariate and multivariable logistic regression analyses controlling for patients' demographics, comorbidities, and operative factors were used to evaluate the predictors of 30-day acute renal failure (ARF). Sensitivity analysis was done to evaluate the role of RAAS in patients with prior kidney disease.

RESULTS

Overall, 6183 patients underwent EVAR for infrarenal AAA during the study period. Of them, 281 patients had RAAS during EVAR (4.5%). The median age of the patients was 74 years; 81.7% of the cohort was male, but a higher proportion of female patients received EVAR + RAAS compared with patients who underwent EVAR only (26.3% vs 17.9%; P < .001). There was no difference between groups in terms of comorbidities, being on dialysis, or functional status, yet the EVAR + RAAS group had a higher proportion of patients with glomerular filtration rate <60 mL/min/1.73 m2 (45.2% vs 37.2%; P = .011). RAAS was associated with significantly higher odds for development of ARF (adjusted odds ratio [aOR], 4.27; 95% confidence interval [CI], 2.06-8.84; P < .001). Other highly predictive factors of 30-day ARF were glomerular filtration rate <60 (aOR, 2.92; 95% CI, 1.47-5.78; P = .002), emergency status (aOR, 2.97; 95% CI, 1.21-7.27; P = .017), and ruptured AAA as the indication for EVAR (aOR, 4.74; 95% CI, 1.80-12.50; P = .002). Patients with prior kidney disease who had EVAR + RAAS demonstrated a 12-fold higher odds for 30-day ARF (aOR, 12.37; 95% CI, 4.66-32.89; P < .001).

CONCLUSIONS

Concurrent RAAS was found to be a significant determinant of adverse renal outcomes after EVAR for infrarenal AAA. This effect was present even after controlling for patients' risk factors that might contribute to postoperative ARF.

Perioperative outcome of endovascular repair for complex abdominal aortic aneurysms

BACKGROUND

As endovascular aneurysm repair (EVAR) continues to advance, eligibility of patients with anatomically complex abdominal aortic aneurysms (AAAs) for EVAR is increasing. However, whether complex EVAR is associated with favorable outcome over conventional open repair and how outcomes compare with infrarenal EVAR remains unclear. This study examined perioperative outcomes of patients undergoing complex EVAR, focusing on differences with complex open repair and standard infrarenal EVAR.

METHODS

We identified all patients undergoing nonruptured complex EVAR, complex open repair, and infrarenal EVAR in the American College of Surgeons National Surgical Quality Improvement Program Targeted Vascular Module. Aneurysms were considered complex if the proximal extent was juxtarenal or suprarenal or when the Zenith Fenestrated endograft (Cook Medical, Bloomington, Ind) was used. Independent risks were established using multivariable logistic regression analysis.

RESULTS

Included were 4584 patients, with 411 (9.0%) undergoing complex EVAR, 395 (8.6%) undergoing complex open repair, and 3778 (82.4%) undergoing infrarenal EVAR. Perioperative mortality was 3.4% after complex EVAR, 6.6% after open repair (P = .038), and 1.5% after infrarenal EVAR (P = .005). Postoperative acute kidney injuries occurred in 2.3% of complex EVAR patients, in 9.5% of those undergoing complex open repair (P < .001), and in 0.9% of infrarenal EVAR patients (P = .007). Compared with complex EVAR, complex open repair was an independent predictor of 30-day mortality (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.1-4.4), renal function deterioration (OR, 4.8; 95% CI, 2.2-10.5), and any complication (OR, 3.7; 95% CI, 2.5-5.5). When complex vs infrarenal EVAR were compared, infrarenal EVAR was associated with favorable 30-day mortality (OR, 0.5; 95% CI, 0.2-0.9), and renal outcome (OR, 0.4; 95% CI, 0.2-0.9).

CONCLUSIONS

In this study assessing the perioperative outcomes of patients undergoing repair for anatomically complex AAAs, complex EVAR had fewer complications than complex open repair but carried a higher risk of adverse outcomes than infrarenal EVAR. Further research is warranted to determine whether the benefits of EVAR compared with open repair for complex AAA treatment are maintained during long-term follow-up.

Monocentric Evaluation of Chimney Versus Fenestrated Endovascular Aortic Repair for Juxtarenal Abdominal Aortic Aneurysm

BACKGROUND

With approval of on-label fenestrated (F-) endovascular aortic repair (EVAR), concerns regarding long-term patency and endoleaks (ELs) after chimney graft (CG)-EVAR were raised. To add supportive data on the value of this technique, we chose to report the midterm results of CG-EVAR in a single center with standardized methods and to compare them to F-EVAR.

METHODS

A retrospective analysis of prospectively gathered data from January 2010 to January 2015 was conducted, and patients with excessive comorbidities for open repair treated by CG-EVAR or F-EVAR were included.

RESULTS

Ninety patients were treated by F-EVAR (88 men, 198 targets vessels) and 31 by CG-EVAR (26 men, 39 targets vessels, 12.9% treated in emergency; P = 0.001). Mean age was significantly higher in the CG group (71.3 ± 8.2 years in the FG group vs. 75.3 ± 6.6; P = 0.02), and there were significantly more patients suffering from preoperative chronic kidney disease (CKD) (13 [14.4%] treated by F-EVAR vs. 12 [38.7%]; P = 0.009). Target vessels were successfully reconstructed in 99.0% (196/198 target vessels) vs. 97.4% (38/39 target vessels) of cases (P = 0.3). In-hospital mortality was significantly higher after CG-EVAR (3.3% vs. 16.1%; P = 0.03). Incidence of acute kidney injury and CKD did not differ significantly between both groups. At 12 and 24 months, overall survival was 91.4% after F-EVAR vs. 82.1% and 81.8% vs. 69.0% (P = 0.4), estimated freedom from aneurysm related reintervention was 93.3% vs. 82.1% and 84.9% vs. 82.1% (P = 0.6), and target vessel's primary patency rate was 97.5% vs. 89.9% (P = 0.06), respectively. Freedom from type I EL's survival was significantly higher after F-EVAR at 12 and 24 months (100% vs. 89.0% and 97.7% vs. 89.0%; P = 0.01), but aneurysm maximum transverse diameter decrease did not differ significantly.

CONCLUSIONS

There are potential advantages to CG-EVAR with off-the-shelf availability, versatility, and low-profile devices. In this series, patients treated by CG-EVAR showed promising and durable midterm results compared with F-EVAR. CG-EVAR and F-EVAR should not be apprehended as opposed strategies but more as complementary ones, while the best indications for CG-EVAR are clarified.

Renal dysfunction and the associated decrease in survival after elective endovascular aneurysm repair

OBJECTIVE

The reported frequency of renal dysfunction after elective endovascular aneurysm repair (EVAR) varies widely in current surgical literature. Published research establishes pre-existing end-stage renal disease as a poor prognostic indicator. We intend to quantify the mortality effect associated with renal morbidity developed postoperatively and to identify modifiable risk factors.

METHODS

All elective EVAR patients with preoperative and postoperative renal function data captured by the Vascular Quality Initiative between January 2003 and December 2014 were examined. The primary study end point was long-term mortality. Preoperative, intraoperative, and postoperative parameters were analyzed to estimate mortality stratified by renal outcome and to describe independent risk factors associated with post-EVAR renal dysfunction.

RESULTS

This study included 14,475 elective EVAR patients, of whom 96.8% developed no post-EVAR renal dysfunction, 2.9% developed acute kidney injury, and 0.4% developed a new hemodialysis requirement. Estimated 5-year survival was significantly different between groups, 77.5% vs 53.5%, respectively, for the no dysfunction and acute kidney injury groups, whereas the new hemodialysis group demonstrated 22.8% 3-year estimated survival (P < .05). New-onset postoperative congestive heart failure (odds ratio [OR], 3.50; 95% confidence interval [CI], 1.18-10.38), return to the operating room (OR, 3.26; 95% CI, 1.49-7.13), and postoperative vasopressor requirement (OR, 2.68; 95% CI, 1.40-5.12) predicted post-EVAR renal dysfunction, whereas a preoperative estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 was protective (OR, 0.33; 95% CI, 0.21-0.53). Volume of contrast material administered during elective EVAR varies 10-fold among surgeons in the Vascular Quality Initiative database, but the average volume administered to patients is statistically similar, regardless of preoperative eGFR. Multivariable logistic regression demonstrated nonsignificant correlation between contrast material volume and postoperative renal dysfunction.

CONCLUSIONS

Any renal dysfunction developing after elective EVAR is associated with decreased estimated long-term survival. Protecting renal function with a rational dosing metric for contrast material linked to preoperative eGFR may better guide treatment.

Assessment of Renal Injury in Patients Undergoing Elective EVAR Using Urinary Neutrophil Gelatin-Associated Lipocalin, Interleukin 18, and Retinol-Binding Protein

Acute kidney injury (AKI) is a recognized complication post-endovascular aneurysm repair (EVAR). Neutrophil gelatin-associated lipocalin (NGAL), interleukin 18 (IL-18), and retinol-binding protein are emerging urinary biomarkers that have shown promise in detecting subclinical and clinical renal impairment. In this study, we assessed changes in these urinary biomarkers as well as serum creatinine (SCr) in patients undergoing EVAR. Urine samples were collected prospectively at 5 time points for each recruited patient: pre-EVAR (baseline) and 6, 12, 24, and 48 hours after the procedure for serial assessment of urinary biomarkers. Serum creatinine was quantified preoperatively and at 24 and 48 hours postoperatively. Serial changes of urinary biomarkers and SCr were assessed. A significant increase in NGAL and IL-18 from baseline was observed ( P < .05), as early as 6 hours for NGAL. A significant rise in levels of NGAL and IL-18 precedes the significant rise in SCr. These findings highlight the potential of emerging urinary biomarkers in detecting early AKI following EVAR.

Contrast-enhanced ultrasound after endovascular aortic repair-current status and future perspectives

An increasing number of patients with abdominal aortic aneurysms (AAAs) are undergoing endovascular aortic repair (EVAR) instead of open surgery. These patients require lifelong surveillance, and the follow-up imaging modality of choice has been traditionally computed tomography angiography (CTA). Repetitive CTA imaging is associated with cumulative radiation exposure and requires the administration of multiple doses of nephrotoxic contrast agents. Contrast-enhanced ultrasound (CEUS) has emerged as an alternative strategy in the follow-up of patients with EVAR and demonstrates high sensitivity and specificity for detection of endoleaks. In fact, a series of studies have shown that CEUS is at least performing equal to computed tomography for the detection and classification of endoleaks. This article summarizes current evidence of CEUS after EVAR and demonstrates its usefulness via various patient cases.

Renal Function is the Main Predictor of Acute Kidney Injury after Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

Postoperative acute kidney injury (AKI) may occur in up to 18% of elective endovascular abdominal aortic aneurysm repair (EVAR) and has been associated with poor outcome; however, it is not clear which patients are at highest risk, to target renoprotection effectively. We sought to determine the predictive factors of AKI after elective EVAR.

METHODS

Overall, 947 patients undergoing elective EVAR between January 2004 and December 2014 were analyzed, using prospectively collected data. Postoperative AKI was defined by serum creatinine change within 48 hr, as per the Kidney Disease Improving Global Outcomes guidelines. Cardiovascular and kidney-disease risk factors were entered in univariate and multivariate analyses to assess influence on AKI development.

RESULTS

Overall, 167 (17.6%) patients developed AKI but only 2 patients required dialysis perioperatively. At multivariate analysis, adjusted for established AKI-risk factors and parameters that differed between groups at baseline, preoperative estimated glomerular filtration rate (eGFR; as per the chronic kidney disease epidemiology [CKD] formula); odds ratio (OR): 1.02 (per unit decrease); 95% confidence interval (CI): 1.003-1.041; P = 0.025; and chronic kidney disease (CKD) stage > 2 (OR: 1.28; 95% CI: 1.249-2.531, P = 0.001) were associated with development of AKI.

CONCLUSIONS

AKI was common after elective infrarenal EVAR and preoperative renal function appears to be the main factor associated with AKI. Patients with a low eGFR need to be targeted with more aggressive renal protection.

Delayed renal dysfunction and flash pulmonary edema post endovascular abdominal aneurysm repair

After endovascular aortic repair (EVAR), the deterioration in long-term renal function is probably multifactorial. Preoperative renal failure is an independent risk factor. Postoperative renal dysfunction can be associated with inadvertent renal artery occlusion, renal artery complications as stenosis, plaque dislodgement, or dissection. Ischemic nephropathy can accelerate hypertension and circulatory congestion. We report a case of coverage of the renal arteries symptomatic with flash pulmonary edema and renal failure 15 months after EVAR, suggesting a delayed endograft migration. The patient had complete resolution of symptoms and renal function after renal artery stenting with placement between endograft and aneurysm to the left renal artery.

Long-Term Renal Function after Endovascular Aneurysm Repair

BACKGROUND AND OBJECTIVES

Endovascular repair (EVAR) is a common treatment for abdominal aortic aneurysm (AAA). However, its long-term effects on renal function remain unclear. We aimed to assess long-term renal dysfunction after EVAR using a contemporary estimate of GFR and to compare long-term renal outcomes in patients after EVAR with open aneurysm repair (OAR) and in patients without an AAA.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

We performed a nested case-matched analysis of 726 patients (using a prospectively maintained database for repairs that took place between January 2000 and May 2010 in a tertiary center): 121 patients undergoing OAR (with data at baseline and 5 years postrepair) were case matched (age, sex, smoking, diabetes, baseline eGFR) to patients undergoing suprarenal and infrarenal fixation EVAR (242 in each group) and to 121 patients undergoing carotid endarterectomy (CEA) without AAA. Changes in eGFR were compared (1 and 5 years).

RESULTS

The OAR patients lost an average of 7.4 ml/min per 1.73 m2 at 5 years (95% confidence interval [95% CI], 4.8 to 10.6), compared with 8.2 ml/min per 1.73 m2 (95% CI, 6.5 to 10.8; P<0.001) for infrarenal-fixation EVAR, 16.9 ml/min per 1.73 m2 (95% CI, 13.0 to 21.9, P<0.001) for suprarenal-fixation EVAR, and 5.4 ml/min per 1.73 m2 (95% CI, 1.7 to 7.5; P<0.001) for CEA. The decrease in eGFR was steeper during the first postoperative year, with each group losing -2.2 ml/min per 1.73 m2 (infrarenal-fixation EVAR), -10.7 ml/min per 1.73 m2 (suprarenal-fixation EVAR), and -4.6 ml/min per 1.73 m2 (OAR), compared with -1.9 ml/min per 1.73 m2 for CEA.

CONCLUSIONS

Elective EVAR is associated with a significant decline in eGFR after 5 years, which is steeper in the first postoperative year and more pronounced compared with a similar population with atherosclerotic disease.

Endovascular treatment of complex aortic aneurysms: prevalence of acute kidney injury and effect on long-term renal function

Objectives

To analyse predictors for short- and long-term renal function changes after fenestrated and branched endovascular aortic repair (EVAR).

Methods

A total of 157 patients underwent fenestrated and branched EVAR. Procedural intra-arterial iodinated contrast volume was documented. Serum creatinine and estimated glomerular filtration rate (eGFR) at baseline, during 48 h following EVAR, at discharge and latest moment of follow-up were recorded. Development of post-EVAR acute kidney injury (AKI; according to AKIN criteria), and potential risk factors for renal failure were recorded. Multivariate regression analyses were used to identify independent risk factors for AKI and eGFR decrease during follow-up.

Results

Forty-three patients (28 %) developed post-EVAR AKI. Long procedure time and occlusion of accessory renal arteries were independent risk factors for development of AKI. (odds ratio (OR) 1.005 per minute, 95 % CI 1.001–1.01; p = 0.025 and OR 3.02, 95 % CI 1.19–8.16; p = 0.029). Post-EVAR AKI was associated with a significantly increased risk for eGFR decrease at discharge and latest follow-up (hazard ratio (HR) 3.47, 95 % CI 1.63–7.36, p = 0.001 and HR 3.01, 95 % CI 1.56–5.80; p = 0.001). Iodinated contrast volume was not an independent risk factor for AKI or eGFR decrease during follow-up.

Conclusion

Development of post-EVAR AKI is an independent risk factor for long-term renal function decrease.

Key Points

• Longer procedure time is associated with an increased risk for AKI.

• Renal perfusion defects on angiography are associated with increased risk for AKI.

• Post-EVAR AKI is associated with higher probability for long-term eGFR decrease.

• Iodinated contrast volume is not an independent risk factor for AKI.

• Iodinated contrast volume is not an independent risk factor for long-term eGFR decrease.

Impact of Fenestrated Endovascular Abdominal Aortic Aneurysm Repair on Renal Function

Purpose: To investigate the impact of fenestrated endovascular aneurysm repair (fEVAR) on renal function perioperatively and at midterm. Methods: A case-controlled study was performed involving 58 patients (mean age 75±7 years; 51 men) who underwent elective fEVAR for a juxtarenal or short-necked abdominal aortic aneurysm (AAA) matched on age, sex, smoking, diabetes, and baseline estimated glomerular filtration rate (eGFR) with a contemporaneous group undergoing open aneurysm repair (OAR) for the same indications. Perioperative incidence of acute kidney injury (AKI) and levels of eGFR at 30 days and 1 year were compared. A systematic literature review was performed to identify studies that had used eGFR as renal outcome after fEVAR; the pooled data were meta-analyzed using an eGFR drop >30% at 1 month and the latest follow-up as endpoints. Results are reported as the pooled proportion and 95% confidence interval (CI). Results: The incidence of AKI after fEVAR was 28% compared to 10% after OAR (p=0.03). Following fEVAR, the mean eGFR dropped from 78±8 to 74±9 mL/min/1.73 m2 at 30 days compared to a change from 79±8 to 80±16 mL/min/1.73 m2 after OAR (p<0.01). However, the absolute drop in eGFR between fEVAR and OAR at 1 year was similar (7 mL/min/1.73 m2; p=0.53); 7% of the fEVAR patients had an eGFR drop >30% at that point compared with none for OAR (p=0.12). The systematic literature review identified eGFR outcomes for 193 fEVAR patients. Combining these patients with the 58 from our cohort study, the pooled proportions of eGFR drop >30% were 20% (95% CI 9% to 39%) at 30 days and 8% (95% CI 0.5% to 13%) at the end of follow-up. Conclusion: fEVAR has a significant perioperative impact on renal function, but 1-year results are similar to OAR. fEVAR patients may benefit from targeted AKI prevention strategies that need to be assessed in relevant studies.

Incidence and Outcomes of Severe Renal Impairment Following Ruptured Abdominal Aortic Aneurysm Repair

INTRODUCTION

Acute kidney injury (AKI) following ruptured abdominal aortic aneurysm (rAAA) repair is common and multifactorial. A standard definition of AKI after endovascular repair (EVAR), the Aneurysm Renal Injury Score (ARISe), has been proposed to facilitate standardised reporting and thus improve understanding of this issue.

METHODS

Data were collected retrospectively on AKI in a prospectively maintained database of all patients treated for rAAA in a single tertiary referral centre since the availability of routine out of hours emergency EVAR. The ARISe score was used to describe the degree of AKI and factors which correlated with poor renal outcomes were assessed.

RESULTS

Two-hundred and five patients were treated between January 2006 and April 2014. Of these, 125 were treated with open repair (OSR) and 80 were treated with EVAR. Severe AKI (defined as ARISe score ≥3) occurred in 36% of patients. After correction for confounders, patients treated with OSR were significantly more likely to develop severe AKI (43% vs. 26%, p = .02). There was no significant difference in preoperative serum creatinine between groups, but increased preoperative serum creatinine was strongly associated with severe AKI postoperatively (p < .001). Age, sex, endograft type, and preoperative CT scanning were not associated with differences in renal outcomes. Clamp position above renal arteries was predictive of severe AKI in patients treated with OSR (p < .01). Patients suffering severe AKI had significantly higher mortality at 30 days and 12 months (28% vs. 5% and 44% vs. 13%, p < .001 for both comparisons).

CONCLUSION

Severe AKI is common following successful repair of rAAA. In this large case series of high-risk patients, OSR was associated with significantly higher rates of severe AKI compared with EVAR, despite the increased dose of contrast involved in EVAR and the older age of these patients. In turn, severe AKI was associated with higher mortality rates.

[Complications following aortic reconstruction surgery]

BACKGROUND

The potential complications following aortic reconstruction surgery are diverse and potentially life-threatening. Besides the well known complications of open aortic repair (OAR) the spectrum of complications has been extended and shifted by the growing use of endovascular aortic repair (EVAR).

AIM

The most common complications of open as well as endovascular aortic surgery are presented in a summarizing review. The focus is placed on the presentation of cardiovascular and nephrological complications, colonic ischemia, as well as aortic graft infections and graft fistulas. Spinal ischemia and endoleaks after EVAR are also discussed. Additionally epidemiological data, risk factors and basic therapeutic principles are outlined.

CONCLUSION

Aortic reconstruction surgery can be associated with severe complications, the main features of which should be known by all surgical specialties.