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

Analysis of high-risk factors and mortality prediction of ruptured abdominal aortic aneurysm

INTRODUCTION

Ruptured abdominal aortic aneurysms (RAAAs) are among the most dangerous emergencies in vascular surgery, with a high death rate and numerous risk factors influencing perioperative death. Therefore, identifying the critical risk factors for RAAAs is crucial to increasing their survival rate. Our aim was to identify those risk factors from a wide range of parameters.

METHODS

Retrospective analysis of hospitalised RAAA patients treated at this center between May 2004 and January 2023. After comparing the preoperative data of patients who survived and those who died, high-risk characteristics influencing the perioperative care of RAAA patients were identified, and logistic regression analysis was carried out. The mean follow-up time was 45.34 months.

RESULTS

During the study period, a total of 155 patients (average age 67.4±71.93 years, 123 (78.85%)males, 32 (20.51%)females) were enrolled. The patients participating in the group were divided into survival group (n = 123) and death group (n = 27). The main differences included hemodynamic instability (51.9% vs 28.5%; P=0.019), sudden cardiac arrest (14.8% vs 1.6%; P=0.010), deterioration of consciousness (40.7% vs 17.1%; P=0.007), renal impairment (22.2% vs 2.4%; P=0.001), chronic kidney disease (18.5% vs3.2%; P=0.010). There is also a history of cancer (Ca) (18.5% vs 4.1%; P=0.021). Risk factors for Endovascular aneurysm repair (EVAR) include diastolic blood pressure ≤ 50 mmHg (36.4% vs 8.0%; P=0.025), renal function impairment (18.2% vs 0; P=0.015), and chronic kidney disease (27.3% vs 4.0%; P=0.028). Risk factors for open surgical repair (OSR) include diastolic blood pressure ≤ 50 mmHg (40.0% vs 6.3%; P=0.014). Finally, the above statistically significant factors were analyzed by Logistic regression analysis, and it was found that diastolic blood pressure ≤ 50mmHg, cardiac arrest, renal function damage and Ca history were independent risk factors. We followed 123 individuals and 14 were lost to follow-up, with an overall survival rate of 43.8%.

CONCLUSION

Hemodynamics, which includes shock, blood pressure, cardiac arrest, deterioration of consciousness, and other conditions, are the primary risk factors for the perioperative death of a ruptured abdominal aortic aneurysm. Simultaneously, diastolic blood pressure ≤50mmHg was found to be associated with risk factors for OSR, whereas renal function impairment, chronic renal illness, and diastolic blood pressure ≤50mmHg were associated with risk for EVAR.

Open Conversion with Explantation of Stent Grafts After Endovascular Aneurysm Repair for Abdominal Aortic Aneurysm

BACKGROUND

Although endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) is widely used worldwide, the fact that it is associated with increased rates of reintervention has been considered a problem. This study aimed to analyze the outcomes of primary open AAA repair and open conversion with explantation of stent grafts after EVAR.

METHODS

In this retrospective study, we enrolled 1,120 patients (open repair, n = 664; EVAR, n = 456) who underwent AAA repair at Kobe University from 1999 to 2019. Of the 664 patients who underwent open repair, 121 (patients who underwent primary open repair (POR) as a concomitant procedure and patients with ruptured AAA) were excluded from the study. The outcomes of POR were compared with those of open conversion with explantation of stent grafts.

RESULTS

Of the 543 patients who underwent open repair, 513 underwent POR and 30 underwent open conversion with explantation of stent grafts. The operation time for POR was significantly less than that for open conversion with explantation. During surgery, patients who underwent open conversion with explantation required significantly more transfusions of red cell concentrate, fresh frozen plasma, and platelet concentrate than those who underwent POR. Overall, 30 patients who underwent open conversion with explantation required a total of 48 reinterventions before surgery. Hospital mortality rates were 0.7% and 0% in the POR and open conversion with explantation groups, respectively (P = 0.62). Although overall survival at 5 years in the POR group was significantly better than that in the open conversion with explantation group (89.3 ± 1.7% vs. 79.5 ± 9.6%; P = 0.01), there were no significant differences between the 2 groups regarding the freedom from aortic event (hospital death, reintervention, and aortic death). According to the multivariate analysis, open conversion with explantation was not an independent risk factor for late death. There were 20 patients who were hesitant to undergo OCE, although we recommended OCE. In a subgroup analysis, the overall mean cost borne by patients who underwent EVAR was approximately 2.3 times higher compared with that borne by patients who underwent POR.

CONCLUSIONS

Although demanding, both early and long-term outcomes of OCE have been favorable in our present study. OCE is highly recommended in patients with persistent sac enlargement after EVAR.

Risk Factors for Acute Renal Failure After Endovascular Aneurysm Repair

BACKGROUND

Acute kidney injury (AKI) after endovascular aortic aneurysm repair (EVAR) is uncommon though carries significant morbidity. Procedural risk factors are not well established for acute renal failure (ARF) that requires initiation of dialysis. The goal of this study was to examine the impact of ARF on patients undergoing EVAR and identify risk factors for ARF using a large, national dataset.

METHODS

Patients undergoing EVAR were identified from the National Surgical Quality Improvement Program (NSQIP) database over 9 years, ending in 2019. Demographics, indication for repair, comorbidities, procedural details, complications, hospital and ICU LOS, and mortality were recorded. Patients were stratified by presence of ARF and compared. Patients were further stratified by indication for EVAR and presence of ARF. Multivariable logistic regression (MLR) analysis was performed to determine the independent predictors of ARF.

RESULTS

18 347 patients were identified. Of these 234 (1.3%) developed ARF requiring dialysis. Mortality (40 vs 1.8%, P < .0001), ICU LOS (5 vs 0 days, P < .0001), and hospital LOS (11 vs 2 days, P < .0001) were all significantly increased in patients with ARF. Multivariable logistic regression identified increasing diameter, creatinine, operative time, preoperative transfusions, ASA class, emergent repair, female gender, and juxtarenal/suprarenal proximal landing zone as predictors of ARF.

CONCLUSIONS

ARF after EVAR causes significant morbidity, prolongs hospitalizations, and increases mortality rates. Those patients at risk of ARF after EVAR should be closely monitored to reduce both morbidity and mortality.

Postoperative Hypoalbuminemia as a Predictor of Acute Kidney Injury After Open Repair of Ruptured Abdominal Aortic Aneurysm

BACKGROUND

Perioperative hypoalbuminemia has a prognostic effect on mortality and morbidity in various cohorts. Patients undergoing open repair of ruptured abdominal aortic aneurysms (rAAA) are at a high risk of hypoalbuminemia due to bleeding and underlying diseases. Hence, this study aimed to investigate the predictive value of immediate postoperative hypoalbuminemia for the risk for acute kidney injury (AKI) in patients undergoing open rAAA repair.

METHODS

We retrospectively reviewed 143 patients who underwent open rAAA repair between January 2008 and May 2022. The patients were divided into two groups according to the presence of postoperative AKI. The perioperative serum albumin levels of the two groups were compared. The patients were further divided into two groups based on the median immediate postoperative albumin level (2.4 g/dL). The incidence of AKI was compared between the two groups. Multivariate logistic regression analysis was performed to assess the predictors of postoperative AKI. Kaplan-Meier survival curves were used to evaluate potential of AKI and albumin level as prognostic factors for mortality.

RESULTS

Immediate postoperative serum albumin was significantly lower in the AKI group than in the non-AKI group (2.11 ± 0.62 g/dL vs. 2.59 ± 0.62 g/dL, p < 0.001). The incidence of postoperative AKI was significantly higher in patients with albumin ≤ 2.4 g/dL than in patients with albumin > 2.4 g/dL (53.8% vs. 27.7%, p = 0.002). Immediate postoperative albumin level was an independent predictor of AKI (Odds ratio [OR], 0.310; 95% confidence interval [CI] 0.165-0.583, p < 0.001) and 1-year mortality (OR, 0.230; 95% CI 0.098-0.542, p = 0.001).

CONCLUSIONS

Immediate postoperative hypoalbuminemia was associated with postoperative AKI and mortality in patients with rAAA.

Acute Kidney Injury Risk and Contrast Volume in Intact Versus Ruptured Endovascular Aneurysm Repair in the Vascular Quality Initiative

Objective

Renal impairment after repair of ruptured abdominal aortic aneurysm has been associated with post-operative mortality. Acute kidney injury (AKI) risk specifically related to contrast administration in endovascular aneurysm repair (EVAR) for intact vs ruptured aneurysms has not been previously described. It was our objective to evaluate the risk of AKI and the association with contrast administration in EVAR for ruptured (rEVAR) and intact (iEVAR) aneurysm repair in the Vascular Quality Initiative (VQI).

Methods

Adult patients less than 90 years old undergoing EVAR in the VQI without prior abdominal aortic surgery or who were not actively on dialysis preoperatively were included. Patients immediately converted to an open repair were excluded. Patients were grouped by repair urgency, and patient and operative characteristics and outcomes compared. Univariable and multivariable analyses were performed to identify factors associated with the primary outcome of AKI. Survival was evaluated by Kaplan-Meier analysis.

Results

Of 38,775 EVAR patients identified, 86.5% underwent elective surgery for an intact aneurysm, 8.4% had urgent surgery for a symptomatic, intact aneurysm, and 5.1% had emergent repair for a ruptured aneurysm. Significant risk factors for AKI included contrast volume, a preoperative eGFR <30 mL/min, procedure urgency, COPD, congestive heart failure (CHF), and total procedure time. The factor most associated with AKI was aneurysm rupture prior to repair (OR 8.6, CI 7.2-10.3, P <.01). The association of contrast volume with the outcome was the least strong with a 4% increase in risk per 25 mL of contrast (OR 1.04, 95% CI 1.01-1.07). With the development of AKI, postoperative survival was reduced regardless of indication.

Conclusions

Of all factors assessed, aneurysm rupture was the most and contrast volume the least associated with AKI after EVAR. Further studies should evaluate methods of preventing post-EVAR AKI.

Time-to-event data meta-analysis of late outcomes of endovascular versus open repair for ruptured abdominal aortic aneurysms

OBJECTIVE

We investigated whether the well-documented perioperative survival advantage of emergency endovascular aneurysm repair (EVAR) compared with open repair would be sustained during follow-up.

METHODS

A systematic review conforming to the PRISMA (preferred reporting items for systematic reviews and meta-analyses) statement standards was conducted to identify studies that had reported the follow-up outcomes of endovascular vs open repair for ruptured abdominal aortic aneurysms. Electronic bibliographic sources (MEDLINE [medical literature analysis and retrieval system online], Embase [Excerpta Medica database], CINAHL [cumulative index to nursing and allied health literature], and CENTRAL [Cochrane central register of controlled trials]) were interrogated using the Healthcare Databases Advanced Search interface (National Institute for Health and Care Excellence, London, United Kingdom). A time-to-event data meta-analysis was performed using the inverse variance method, and the results were reported as summary hazard ratios (HRs) and associated 95% confidence intervals (CIs). Mixed effects regression was applied to investigate the outcome changes over time. The quality of the body of evidence was appraised using the GRADE (grades of recommendation, assessment, development, and evaluation) system.

RESULTS

Three randomized controlled trials and 22 observational studies reporting a total of 31,383 patients were included in the quantitative synthesis. The mean follow-up duration across the studies ranged from 232 days to 4.9 years. The overall all-cause mortality was significantly lower after EVAR than after open repair (HR, 0.79; 95% CI, 0.73-0.86). However, the postdischarge all-cause mortality was not significantly different (HR, 1.10; 95% CI, 0.85-1.43). The aneurysm-related mortality, which was reported by one randomized controlled trial, was not significantly different between EVAR and open repair (HR, 0.89; 95% CI, 0.69-1.15). Meta-regression showed the mortality difference in favor of EVAR was more pronounced in more recent studies (P = .069) and recently treated patients (P = .062). The certainty for the body of evidence for overall and postdischarge all-cause mortality was judged to be low and that for aneurysm-related mortality to be high.

CONCLUSIONS

EVAR showed a sustained mortality benefit during follow-up compared with open repair. A wider adoption of an endovascular-first strategy is justified.

Numerical Simulation of Blood Flows in Patient-specific Abdominal Aorta with Primary Organs

The abdominal aorta is the largest artery in the abdominal cavity that supplies blood flows to vital organs through the complex visceral arterial branches, including the celiac trunk (the liver, stomach, spleen, etc.), the renal arteries (the kidneys) and the superior and inferior mesenteric arteries (the small and large intestine, pancreas, etc.). An accurate simulation of blood flows in this network of arteries is important for the understanding of the hemodynamics in various organs of healthy and diseased patients, but the computational cost is very high. As a result, most researchers choose to focus on a portion of the artery or use a low-dimensional approximation of the artery. In the present work, we introduce a parallel algorithm for the modeling of pulsatile flows in the abdominal aorta with branches to the primary organs, and an organ-based two-level method for calculating the resistances for the outflow boundary conditions. With this highly parallel approach, the simulation of the blood flow for a cardiac cycle of the anatomically detailed aorta can be obtained within a few hours, and the blood distribution to organs including liver, spleen and kidneys are also computed with certain accuracy. Moreover, we discuss the significant hemodynamic differences resulted from the influence of the peripheral branches. In addition, we examine the accuracy of the results with respect to the mesh size and time-step size and show the high parallel scalability of the proposed algorithm with up to 3000 processor cores.

Abdominal aortic aneurysms part two: Surgical management, postoperative complications and surveillance

Large, symptomatic and ruptured abdominal aortic aneurysms are usually treated surgically if patients are deemed fit enough. This may be achieved through endovascular or open surgical repair. The type of treatment that a patient receives is dependant on many factors, such as the rupture status of the aneurysm. Each approach is also associated with different risks and postoperative complications. Multiple guidelines exist to inform the surgical management of abdominal aortic aneurysms. This literature review combines these recommendations and explores the evidence upon which they are based. In addition, it highlights the key perioperative considerations that need to be considered in cases of unruptured and ruptured abdominal aortic aneurysms.

Long-term Outcomes Following Endovascular Aneurysm Repair for Ruptured Abdominal Aortic Aneurysms

Purpose: To investigate the long-term outcomes of endovascular aneurysm repair (EVAR) for ruptured abdominal aortic aneurysm (rAAA) from a single center over an 11-year period. Materials and Methods: A retrospective analysis was conducted of 121 patients (median age 78 years; 100 men) with rAAA who underwent emergency EVAR at a single tertiary vascular center from January 2006 to December 2016. The study included only ruptures confirmed by evidence of hematoma on preoperative computed tomography; both iliac and aortic aneurysm ruptures were eligible. The primary outcome measures included mortality and reintervention rates. Kaplan-Meier estimates of survival and freedom from reintervention are reported with the 95% confidence interval (CI). Results: In-hospital and 30-day mortality rates for emergency EVAR were 16.5%; 90-day mortality was 24.0%. The mortality estimates were 27.3% (95% CI 20% to 36%) at 1 year and 61.7% (95% CI 51% to 72%) at 5 years. In the observation period to 2017, 63 reinterventions were performed on 37 patients (30.6%). Median time to the first reintervention was 3.2 years. Freedom from reintervention in surviving patients at 1 year was 86% (95% CI 72% to 94%) and 51% (95% CI 26% to 71%) at 5 years. Four patients (3.3%) had a secondary sac rupture over the study period. Conclusion: Emergency EVAR for ruptured AAA can be performed with acceptable short-term outcomes; however, long-term surveillance is necessary, and reintervention is common.

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.

Die traumatische Aortenruptur

Verkehrsunfälle sind für den größten Teil der traumatischen Aortenrupturen verantwortlich, meist zusammen mit weiteren schweren Begleitverletzungen. Die prähospitale Sterblichkeit ist hoch. Bei Verdacht auf eine beteiligte Aortenverletzung, aufgrund eines hohen traumatic aortic injury scores, ist eine Computertomographie durchzuführen. Es erfolgt eine Triage der Verletzungen, und die Versorgungspriorität der Aorta richtet sich nach dem Schweregrad der Aorten- und Begleitverletzungen sowie dem Zustand des Patienten. Bis zur definitiven Versorgung der aortalen Läsion muss der Blutdruck konsequent gesenkt werden. Grad I und II können in Einzelfällen unter enger Kontrolle inital konservativ gemanagt werden. Grad III (gedeckte Ruptur) und Grad IV (freie Ruptur) benötigen eine raschestmögliche Versorgung (interventionell, chirurgisch). In ausgesuchten Fällen kann auch eine verzögerte Versorgung günstig sein.

Als bevorzugte Versorgungsform hat sich die interventionelle Stentgrafttherapie etabliert.

Predictors of Acute Kidney Injury Following Elective Open and Endovascular Aortic Repair for Abdominal Aortic Aneurysm

Objective: To investigate the predictors of acute kidney injury (AKI) following surgery for abdominal aortic aneurysm.

Materials and Methods: Subjects were 642 non-hemodialysis patients (open aortic repair [OAR] group, n=453; endovascular aortic repair [EVAR] group, n=189) who underwent elective surgery between 2009 and 2015. AKI was assessed according to the Kidney Disease Improving Global Outcomes criteria. In-hospital mortality and incidence of AKI were compared between the OAR and EVAR groups. The effect of AKI on outcomes and predictors of AKI were examined in both groups.

Results: In-hospital mortalities were 0.7% (3/453) in the OAR group and 0.5% (1/189) in the EVAR group. The incidence of AKI increased in the OAR group (14.1% vs. 3.7%, P<0.01). In the OAR group, in-hospital mortality (0% vs. 4.7%, P<0.01) increased in patients with AKI. In the OAR group, hemoglobin level <10 g/dL, estimated glomerular filtration rate <60 mL/min/1.73 m², operation time >300 min, history of ischemic heart disease, and amount of bleeding >1,000 mL were predictors of AKI. In the EVAR group, amount of transfusion>1,000 mL was a predictor of AKI, but AKI was not found to worsen outcomes.

Conclusion: AKI affected outcomes of OAR. Knowledge of predictors may optimize perioperative care.

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.

Weekend effect in non-elective abdominal aortic aneurysm repair

Background

The ‘weekend effect’ describes the phenomenon where patient outcomes appear worse for those admitted at the weekend. It has been used recently to justify significant changes in UK health policy. Recent evidence has suggested that the effect may be due to a combination of inadequate correction for confounding factors and inaccurate coding. The effects of these factors were investigated in patients with acute abdominal aortic aneurysm (AAA).

Methods

Patients undergoing non‐elective AAA repair entered into the UK National Vascular Registry from January 2013 until December 2015 were included in a case–control study. The patients were divided according to whether they were treated during the week (Monday 08.00 hours to Friday 17.00 hours) or at the weekend. Data extracted included demographics, co‐morbidities, preoperative medications and baseline blood test results, as well as outcomes. Coding issues were investigated by looking at patients treated for ruptured, symptomatic or asymptomatic AAA within the non‐elective cohort. The primary outcome was in‐hospital mortality. Secondary outcomes included length of inpatient stay, and cardiac, respiratory and renal complications.

Results

The mortality rate appeared to be higher at the weekend (odds ratio (OR) 1·69, 95 per cent c.i. 1·47 to 1·94; P < 0·001), but this effect disappeared when confounding factors and coding issues were corrected for (corrected OR for ruptured AAA 1·09, 0·92 to 1·29; P = 0·330). Differences in outcomes were similar for prolonged length of hospital stay (uncorrected OR 1·21, 95 per cent c.i. 1·06 to 1·37, P = 0·005; corrected OR for ruptured AAA 1·06, 0·91 to 1·10, P = 0·478), and morbidity outcomes.

Conclusion

After appropriate correction for confounding factors and coding effects, there was no evidence of a significant weekend effect in the treatment of non‐elective AAA in the UK.

Comparative clinical effectiveness and cost effectiveness of endovascular strategy v open repair for ruptured abdominal aortic aneurysm: three year results of the IMPROVE randomised trial

Objective To assess the three year clinical outcomes and cost effectiveness of a strategy of endovascular repair (if aortic morphology is suitable, open repair if not) versus open repair for patients with suspected ruptured abdominal aortic aneurysm.Design Randomised controlled trial.Setting 30 vascular centres (29 in UK, one in Canada), 2009-16.Participants 613 eligible patients (480 men) with a clinical diagnosis of ruptured aneurysm, of whom 502 underwent emergency repair for rupture.Interventions 316 patients were randomised to an endovascular strategy (275 with confirmed rupture) and 297 to open repair (261 with confirmed rupture).Main outcome measures Mortality, with reinterventions after aneurysm repair, quality of life, and hospital costs to three years as secondary measures.Results The maximum follow-up for mortality was 7.1 years, with two patients in each group lost to follow-up by three years. After similar mortality by 90 days, in the mid-term (three months to three years) there were fewer deaths in the endovascular than the open repair group (hazard ratio 0.57, 95% confidence interval 0.36 to 0.90), leading to lower mortality at three years (48% v 56%), but by seven years mortality was about 60% in each group (hazard ratio 0.92, 0.75 to 1.13). Results for the 502 patients with repaired ruptures were more pronounced: three year mortality was lower in the endovascular strategy group (42% v 54%; odds ratio 0.62, 0.43 to 0.88), but after seven years there was no clear difference between the groups (hazard ratio 0.86, 0.68 to 1.08). Reintervention rates up to three years were not significantly different between the randomised groups (hazard ratio 1.02, 0.79 to 1.32); the initial rapid rate of reinterventions was followed by a much slower mid-term reintervention rate in both groups. The early higher average quality of life in the endovascular strategy versus open repair group, coupled with the lower mortality at three years, led to a gain in average quality adjusted life years (QALYs) at three years of 0.17 (95% confidence interval 0.00 to 0.33). The endovascular strategy group spent fewer days in hospital and had lower average costs of -£2605 (95% confidence interval -£5966 to £702) (about €2813; $3439). The probability that the endovascular strategy is cost effective was >90% at all levels of willingness to pay for a QALY gain.Conclusions At three years, compared with open repair, an endovascular strategy for suspected ruptured abdominal aortic aneurysm was associated with a survival advantage, a gain in QALYs, similar levels of reintervention, and reduced costs, and this strategy was cost effective. These findings support the increasing use of an endovascular strategy, with wider availability of emergency endovascular repair.Trial registration Current Controlled Trials ISRCTN48334791; ClinicalTrials NCT00746122.

Mortality After Elective and Ruptured Abdominal Aortic Aneurysm Surgical Repair: 12-Year Single-Center Experience of Estonia

Background and Aims:

Abdominal aortic aneurysm is a degenerative vascular pathology with high mortality due to its rupture, which is why timely treatment is crucial. The current single-center retrospective study was undertaken to analyze short- and long-term all-cause mortality after operative treatment of abdominal aortic aneurysm and to examine the factors that influence outcome.

Material and Methods:

The data of all abdominal aortic aneurysm patients treated with open repair or endovascular aneurysm repair in 2004–2015 were retrospectively retrieved from the clinical database of Tartu University Hospital. The primary endpoint was 30-day, 90-day, and 5-year all-cause mortality. The secondary endpoint was determination of the risk factors for mortality.

Results and Conclusion:

Elective abdominal aortic aneurysm repair was performed on 228 patients (mean age 71.8 years), of whom 178 (78%) were treated with open repair and 50 (22%) with endovascular aneurysm repair. A total of 48 patients with ruptured abdominal aortic aneurysm were treated with open repair (mean age 73.8 years) at the Department of Vascular Surgery, Tartu University Hospital, Estonia. Mean follow-up period was 4.2 ± 3.3 years. In patients with elective abdominal aortic aneurysm, 30-day, 90-day, and 5-year all-cause mortality rates were 0.9%, 2.6%, and 32%, respectively. In multivariate analysis, the main predictors for 5-year mortality were preoperative creatinine value and age (p < 0.05). In patients with ruptured abdominal aortic aneurysm, 30-day, 90-day, and 5-year all-cause mortality rates were 22.9%, 33.3%, and 55.1%, respectively. In multivariate analysis, the risk factors for 30-day mortality in ruptured abdominal aortic aneurysm were perioperative hemoglobin and lactate levels (p < 0.05). According to this study, the all-cause mortality rates of elective abdominal aortic aneurysm and ruptured abdominal aortic aneurysm at our hospital were comparable to those at other centers worldwide. Even though some variables were identified as potential predictors of survival, the mortality rates after ruptured abdominal aortic aneurysm remain high. Early diagnosis, timely treatment, and detection of the risk factors for abdominal aortic aneurysm progression would improve survival in patients with abdominal aortic aneurysm.

Risk factors and early outcomes of acute renal injury after thoracic aortic endograft repair for type B aortic dissection

Background

Thoracic endovascular aortic repair (TEVAR) has become an emerging treatment modality for acute type B aortic dissection (TBAD) patients in recent years. The risk factors and impacts of acute kidney injury (AKI) after percutaneous TEVAR, however, have not been widely established.

Methods

We retrospectively studied the clinical records of 305 consecutive patients who admitted to our institution and had TEVAR for TBAD between December 2009 and June 2013. The patients were routinely monitored for their renal functions preoperatively until 7 days after TEVAR. The Kidney Disease Improving Global Guidelines (KDIGO) criteria were used for AKI.

Results

Of the total 305 consecutive patients, 84 (27.5%) developed AKI after TEVAR, comprising 66 (21.6%) patients in KDIGO stage 1, 6 (2.0%) patients in stage 2 and 12 (3.9%) patients in stage 3. From the logistic regression analysis, systolic blood pressure (SBP) on admission >140 mmHg (odds ratio [OR], 2.288; 95% CI, 1.319–3.969) and supra-aortic branches graft bypass hybrid surgery (OR, 3.228; 95% CI, 1.526–6.831) were independent risk factors for AKI after TEVAR. Local anesthesia tended to be a protective factor (OR, 0.563; 95% CI, 0.316–1.001). The preoperative renal function, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker or statin administration, volume of contrast agent, range of TBAD and false lumen involving renal artery were not associated with post-operation AKI. The in-hospital mortality and major adverse events were markedly increased with the occurrence of AKI (7.1% vs 0.9%, P=0.006; 14.3% vs 3.2%, P<0.001, respectively).

Conclusions

TEVAR for TBAD has a high incidence of AKI, which is associated with worse in-hospital outcomes. SBP on admission and supra-aortic branches graft bypass hybrid surgery were the most significant risk factors. Renopreventive measures should be considered in high-risk patients.

A retrospective observational cohort study investigating the association between acute kidney injury and all-cause mortality among patients undergoing endovascular repair of abdominal aortic aneurysms

BACKGROUND

Acute kidney injury (AKI) has been found to be associated with short- and long-term mortality and morbidity in various clinical settings. However, it is unknown whether AKI after endovascular repair of abdominal aortic aneurysms (EVAR) is associated with postoperative mortality.

METHODS

This observational study analyzed patients who underwent EVAR. The primary outcome was all-cause mortality. The outcomes of patients with and without postoperative AKI were compared using the Kaplan-Meier method and log-rank test. Factors with P < 0.05 on the univariate analysis were entered into the multivariate Cox regression model. Predictors of AKI were also determined using Cox univariate and multivariate analysis. The identified predictors of AKI were excluded from multivariate analysis for all-cause mortality because these factors could intermediate outcome.

RESULTS

There were 490 eligible patients. After a follow-up of 28.3 (16.8) months [mean (standard deviation)], 62 patients (12.7%) died. AKI occurred in 59 patients (12.0%). AKI was found by the log-rank test to be associated with a significant increase of all-cause mortality (P < 0.001). Preoperative estimated glomerular filtration rate, preoperative peripheral vascular disease, and emergency surgery were found to be independent predictors of AKI and these variables were excluded from the main analysis. Multivariate analysis showed AKI [hazard ratio (HR) = 1.19, 95% confidence interval (CI) 1.01-3.60, P = 0.045] and transfusion (HR = 1.05, 95% CI 1.01-1.09, P = 0.011) were independent predictors of mortality.

CONCLUSIONS

In the present study, AKI and transfusion were associated with significant increases in all-cause mortality after EVAR.

The incidence, risk factors and in-hospital mortality of acute kidney injury in patients after abdominal aortic aneurysm repair surgery

Background

Acute kidney injury (AKI) is a severe complication associated with abdominal aortic aneurysm (AAA) repair. In this study, we evaluated the incidence, risk factors and in-hospital mortality of AKI in patients after the AAA repair surgery.

Methods

A total of 314 Chinese AAA patients who underwent endovascular aneurysm repair (EVAR) or open aneurysm repair (OPEN) were enrolled in this study. AKI was diagnosed according to the 2012 KDIGO criteria. Logistic regression modeling was used to explore risk factors of AKI, while risk factors associated with in-hospital mortality in AKI patients were investigated using Cox proportional hazards model and Kaplan-Meier analysis, respectively. Multicollinearity analysis was performed to identify the collinearity between the variables before logistic regression analysis and Cox proportional hazards analysis.

Results

Among 314 patients, 94 (29.9%) developed AKI after AAA repair surgery. Severity of AKI and ruptured AAA were independently associated with an increase in in-hospital mortality in AKI patients after AAA repair. Kaplan-Meier analysis identified severity of AKI as being negatively associated with hospital survival in AKI patients. Risk factors associated with AKI included cardiovascular disease (OR 3.169, 95% confidence interval (CI) 1.538 to 6.527, P = 0.002), decreased eGFR (OR 0.965, 95%CI 0.954 to 0.977, P < 0.001), ruptured AAA (OR 2.717, 95%CI 1.320 to 5.592, P = 0.007), renal artery involvement (OR 2.903, 95%CI 1.219 to 6.912, P = 0.016) and OPEN (OR 2.094, 95%CI 1.048 to 4.183, P = 0.036). Further subgroup analysis identified OPEN as an important risk factor of AKI in ruptured AAA patients but not in ruptured AAA patients. The incidence of AKI was significantly lower in EVAR than in OPEN (27.1% vs. 42.8%) and, similarly lower in nonruptured AAA than in ruptured AAA (26.2% vs. 48.1%).

Conclusion

One-third of AAA patients developed AKI after repair surgery. Severity of AKI was associated with reduced survival rate in AAA patients who developed postoperative AKI. Decreased preoperative creatinine clearance, cardiovascular disease, ruptured AAA and OPEN were independent risk factors for postoperative AKI in all 314 AAA patients. Although a lower rate of incident AKI was observed in EVAR compared with OPEN, subgroup analysis of ruptured AAA versus nonruptured AAA showed that EVAR was an independent protective factor for AKI only in ruptured AAA patients but not in nonruptured AAA patients.

Predictors of renal dysfunction after endovascular and open repair of abdominal aortic aneurysms

OBJECTIVE

Renal complications after repair of abdominal aortic aneurysms (AAAs) have been associated with increased morbidity and mortality. However, limited data have assessed risk factors for renal complications in the endovascular era. This study aimed to identify predictors of renal complications after endovascular AAA repair (EVAR) and open repair.

METHODS

Patients who underwent EVAR or open repair of a nonruptured infrarenal AAA between 2011 and 2013 were identified in the National Surgical Quality Improvement Project Targeted Vascular module. Patients on hemodialysis preoperatively were excluded. Renal complications were defined as new postoperative dialysis or creatinine increase >2 mg/dL. Patient demographics, comorbidities, glomerular filtration rate (GFR), operative details, and outcomes were compared using univariate analysis between those with and without renal complications. Multivariable logistic regression was used to identify independent predictors of renal complications.

RESULTS

We identified 4503 patients who underwent elective repair of an infrarenal AAA (EVAR: 3869, open repair: 634). Renal complication occurred in 1% of patients after EVAR and in 5% of patients after open repair. There were no differences in comorbidities between patients with and without renal complications. A preoperative GFR <60 mL/min/1.73m2 occurred more frequently among patients with renal complications (EVAR: 81% vs 37%, P < .01; open: 60% vs 34%, P < .01). The 30-day mortality was also significantly increased (EVAR: 55% vs 1%, P < .01; open: 30% vs 4%, P < .01). After adjustment, renal complications were strongly associated with 30-day mortality (odds ratio [OR], 38.3; 95% confidence interval [CI], 20.4-71.9). Independent predictors of renal complications included GFR <60 mL/min/1.73m2 (OR, 4.6; 95% CI, 2.4-8.7), open repair (OR, 2.6; 95% CI, 1.3-5.3), transfusion (OR, 6.1; 95% CI, 3.0-12.6), and prolonged operative time (OR, 3.0; 95% CI, 1.6-5.6).

CONCLUSIONS

Predictors of renal complications include elevated baseline GFR, open approach, transfusion, and prolonged operative time. Given the dramatic increase in mortality associated with renal complications, care should be taken to use renal protective strategies, achieve meticulous hemostasis to limit transfusions, and to use an endovascular approach when technically feasible.

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.

Ascorbic acid ameliorates renal injury in a murine model of contrast-induced nephropathy

BACKGROUND

Contrast induced nephropathy (CIN) is the commonest cause of iatrogenic renal injury and its incidence has increased with the advent of complex endovascular procedures. Evidence suggests that ascorbic acid (AA) has a nephroprotective effect in percutaneous coronary interventions when contrast media are used. A variety of biomarkers (NGAL, NGAL:creatinine, mononuclear cell infiltration, apoptosis and RBP-4) in both the urine and kidney were assayed using a mouse model of CIN in order to determine whether AA can reduce the incidence and/or severity of renal injury.

METHODS

Twenty-four BALB/c mice were divided into 4 groups. Three groups were exposed to high doses of contrast media (omnipaque) in a well-established model of CIN, and then treated with low or high dose AA or placebo (saline). CIN severity was determined by measurement of urinary neutrophil gelatinase-associated lipocalin (NGAL):creatinine at specific time intervals. Histological analysis was performed to determine the level of mononuclear inflammatory infiltration as well as immunohistochemistry to determine apoptosis in the glomeruli by staining for activated caspase-3 and DNA nicking (TUNEL assays). Reverse transcriptase PCR (rtPCR) of mRNA transcripts prepared from mRNA extracted from mouse kidneys was also performed for both lipocalin-2 (Lcn2) encoding NGAL and retinol binding protein-6 (RBP4) genes. NGAL protein expression was also confirmed by ELISA analysis of kidney lysates.

RESULTS

Urinary NGAL:creatinine ratio was significantly lower at 48 h with a 44% and 62% (204.3μg/mmol versus 533.6μg/mmol, p = 0.049) reduction in the low and high dose AA groups, respectively. The reduced urinary NGAL:creatinine ratio remained low throughout the time period assessed (up to 96 h) in the high dose AA group. In support of the urinary analysis ELISA analysis of NGAL in kidney lysates also showed a 57% reduction (12,576 ng/ml versus 29,393 ng/ml) reduction in the low dose AA group. Immunohistochemistry for apoptosis demonstrated decreased TUNEL and caspase-3 expression in both low and high dose AA groups.

CONCLUSIONS

Ascorbic acid reduced the frequency and severity of renal injury in this murine model of CIN. Further work is required to establish whether AA can reduce the incidence of CIN in humans undergoing endovascular procedures.

Analysis of in hospital mortality and long-term survival excluding in hospital mortality after open surgical repair of ruptured abdominal aortic aneurysm

Purpose

The aim of this study was to confirm the factors that affect the mortality associated with the open surgical repair of ruptured abdominal aortic aneurysm (rAAA) and to analyze the long-term survival rates.

Methods

A retrospective review was performed on a prospectively collected database that included 455 consecutive patients who underwent open surgical repair for AAA between January 2001 and December 2012. We divided our analysis into in-hospital and postdischarge periods and analyzed the risk factors that affected the long-term survival of rAAA patients.

Results

Of the 455 patients who were initially screened, 103 were rAAA patients, and 352 were non-rAAA (nAAA) patients. In the rAAA group, 25 patients (24.2%) died in the hospital and 78 were discharged. Long-term survival was significantly better in the nAAA group (P = 0.001). The 2-, 5-, and 10-year survival rates of the rAAA patients were 87%, 73.4%, and 54.1%, respectively. Age (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.02–.08; P < 0.001) and aneurysm rupture (HR, 1.96; 95% CI, 1.12–.44; P = 0.01) significantly affected long-term survival.

Conclusion

Preoperative circulatory failure is the most common cause of death for in-hospital mortality of rAAA patients. After excluding patients who have died during the perioperative period, age is the only factor that affects the survival of rAAA patients.