Early outcomes of endovascular versus open abdominal aortic aneurysm repair in the National Surgical Quality Improvement Program–Private Sector (NSQIP–PS)

Effect of Chronic Kidney Disease on 30-Day Outcomes in Endovascular Repair of Complex Abdominal Aortic Aneurysm

BACKGROUND

Chronic kidney disease (CKD) has been identified as an independent predictor of poorer long-term prognosis after endovascular aneurysm repair (EVAR) for complex abdominal aortic aneurysm (AAA). However, its impact on short-term perioperative outcomes is conflicting, which can be important for preoperative risk stratification. This study aimed to evaluate the 30-day outcomes of patients with CKD following non-ruptured complex EVAR in a national registry.

METHODS

Patients who had EVAR for complex AAA were identified in ACS-NSQIP targeted database from 2012-2022. Complex AAA included juxtarenal, suprarenal, or pararenal proximal extent, Type IV thoracoabdominal aneurysm, and/or aneurysms treated with Zenith Fenestrated endograft. Exclusion criteria included age<18 years, ruptured AAA, acute intraoperative conversion to open, emergency presentation, and dialysis. Multivariable logistic regression was used to compare 30-day postoperative outcomes of CKD and non-CKD patients, where demographics, baseline characteristics, aneurysm diameter, distant aneurysm extent, anesthesia, and concomitant procedures were adjusted.

RESULTS

There were 695 (39.33%) and 1072 (60.67%) patients with and without CKD, respectively, who underwent EVAR for complex AAA. Patients with and without CKD have comparable 30-day mortality (aOR = 1.165, 95 CI = 0.646-2.099, P = 0.61). However, CKD patients had a higher risk of renal complications (aOR = 2.647, 95 CI = 1.399-5.009, P < 0.01) including higher progressive renal insufficiency (aOR = 3.707, 95 CI = 1.329-10.338, P = 0.01) and acute renal failure requiring renal replacement therapy (aOR = 2.533, 95 CI = 1.139-5.633, P = 0.02). All other 30-day outcomes were comparable between CKD and non-CKD patients.

CONCLUSION

Patients with CKD had similar 30-day mortality and morbidity rates but a higher risk of postoperative renal complications. Therefore, meticulous preoperative planning and postoperative management, which may include optimal hydration, appropriate contrast use, and close renal function monitoring, are essential for patients with CKD after complex EVAR.

Malnutrition is associated with adverse 30-day outcomes after endovascular repair of abdominal aortic aneurysm

BACKGROUND

Malnutrition is particularly pertinent in patients undergoing vascular surgery, who frequently present with a high burden of comorbidities and advanced age that can impede nutrient absorption. While previous studies have established that vascular surgery patients with malnutrition had poorer outcomes, the impact of nutritional status in patients undergoing endovascular aneurysm repair (EVAR) has not yet been investigated. Therefore, this study aimed to assess the effect of malnutrition on 30-day outcomes following non-ruptured EVAR.

METHODS

Patients who had infrarenal EVAR were identified in the ACS-NSQIP targeted database from 2012-2022. Exclusion criteria included age less than 18 years, ruptured aneurysm, and emergency. Malnutrition was defined as patients with preoperative weight loss of greater than 10% decrease in body weight in the 6 months immediately preceding the surgery. A 1:5 propensity-score matching was used to match demographics, baseline characteristics, aneurysm diameter, distant aneurysm extent, anesthesia, and concomitant procedures between patients with and without malnutrition. Thirty-day postoperative outcomes were examined.

RESULTS

There were 154 (0.94%) patients with malnutrition who went under non-ruptured EVAR. Meanwhile, 16,309 patients without malnutrition went under intact EVAR, where 737 of them were matched to all malnutrition patients. Malnourished patients had more comorbidity burdens. After propensity-score matching, patients with malnutrition had elevated but non-significant 30-day mortality (5.92% vs 2.99%, p = .09). However, malnutrition patients had higher risks of renal complications (2.63% vs 0.68%, p = .04), bleeding requiring transfusion (22.37% vs 14.38%, p = .02), and unplanned reoperation (11.18% vs 4.88%, p = .01), as well as longer length of stay (6.11 ± 7.91 vs 4.44 ± 6.22 days, p < .02).

CONCLUSION

Patients with malnutrition experienced higher rates of morbidity after non-ruptured EVAR. Targeting malnutrition could be a strategy for preventing complications after EVAR and proper preoperative malnutritional management could be warranted.

Preoperative Congestive Heart Failure Is Associated with Higher 30-Day Myocardial Infarction and Pneumonia after Endovascular Repair of Abdominal Aortic Aneurysm

INTRODUCTION

Preoperative congestive heart failure (CHF) is associated with higher postoperative mortality and complications in noncardiac surgery. However, postoperative outcomes for patients with preoperative CHF undergoing endovascular aneurysm repair (EVAR) have not been thoroughly established. This study evaluated the effect of preoperative CHF on 30-day outcomes following nonemergent intact EVAR using a large-scale national registry.

METHODS

Patients who had infrarenal EVAR were identified in the ACS-NSQIP database from 2012 to 2022. A 1:5 propensity-score matching was used to match demographics, baseline characteristics, aneurysm diameter, distant aneurysm extent, anesthesia, and concomitant procedures between patients with and without preoperative CHF. Thirty-day postoperative outcomes were examined.

RESULTS

467 (2.84%) CHF patients underwent intact EVAR. Meanwhile, 15,996 non-CHF patients underwent EVAR, where 2,248 of them were matched to all CHF patients. Patients with and without preoperative CHF had comparable 30-day mortality (3.02% vs. 2.62%, p = 0.64). However, CHF patients had higher myocardial infarction (3.02% vs. 1.47%, p = 0.03), pneumonia (3.23% vs. 1.73%, p = 0.04), 30-day readmission (p = 0.01), and longer length of stay (p < 0.01).

CONCLUSION

While patients with and without preoperative CHF had comparable 30-day mortality rates, those with CHF faced higher risks of cardiopulmonary complications. Effective management of preoperative CHF may help prevent postoperative complications in these patients.

Locoregional Anesthesia Has Lower Risks of Cardiac Complications Than General Anesthesia After Prolonged Endovascular Repair of Abdominal Aortic Aneurysms

OBJECTIVES

Although general anesthesia is the primary anesthesia in endovascular aneurysm repair (EVAR), some studies suggest locoregional anesthesia could be a feasible alternative for eligible patients. However, most evidence was from retrospective studies and was subjected to an inherent selection bias that general anesthesia is often chosen for more complex and prolonged cases. To mitigate this selection bias, this study aimed to compare 30-day outcomes of prolonged, nonemergent, intact, infrarenal EVAR in patients undergoing locoregional or general anesthesia. In addition, risk factors associated with prolonged operative time in EVAR were identified.

DESIGN

Retrospective large-scale national registry study.

SETTING

American College of Surgeons National Surgical Quality Improvement Program targeted database from 2012 to 2022.

PARTICIPANTS

A total of 4,075 out of 16,438 patients (24.79%) had prolonged EVAR. Among patients with prolonged EVAR, 324 patients (7.95%) were under locoregional anesthesia. There were 3,751 patients (92.05%) under general anesthesia, and 955 of them were matched to the locoregional anesthesia cohort.

INTERVENTIONS

Patients undergoing infrarenal EVAR were included. Exclusion criteria included age <18 years, emergency cases, ruptured abdominal aortic aneurysm, and acute intraoperative conversion to open. Only cases with prolonged operative times (>157 minutes) were selected. A 1:3 propensity-score matching was used to address demographics, baseline characteristics, aneurysm diameter, distant aneurysm extent, and concomitant procedures between patients under locoregional and general anesthesia. Thirty-day postoperative outcomes were assessed. Moreover, factors associated with prolonged EVAR were identified by multivariate logistic regression.

MEASUREMENTS AND MAIN RESULTS

Except for general anesthesia contraindications, patients undergoing locoregional or general anesthesia exhibited largely similar preoperative characteristics. After propensity-score matching, patients under locoregional and general anesthesia had a lower risk of myocardial infarction (0.93% v 2.83%, p = 0.04), but comparable 30-day mortality (3.72% v 2.72%, p = 0.35) and other complications. Specific concomitant procedures, aneurysm anatomy, and comorbidities associated with prolonged EVAR were identified.

CONCLUSIONS

Locoregional anesthesia can be a safe and effective alternative to general anesthesia, particularly in EVAR cases with anticipated complexity and prolonged operative times, as it offers the potential benefit of reduced cardiac complications. Risk factors associated with prolonged EVAR can aid in preoperative risk stratification and inform the decision-making process regarding anesthesia choice.

Preoperative Anemia Is Associated With Postoperative Renal Failure After Elective Open Aortic Repair

INTRODUCTION

Preoperative anemia has been consistently shown to be a risk factor for acute kidney injury (AKI) after cardiac surgery. However, this association has not been examined in the open abdominal aortic aneurysm repair (OAR) population and is the subject of this analysis.

METHODS

Targeted Vascular Module from the American College of Surgeons National Surgical Quality Improvement Program was queried for patients undergoing OAR from 2013 to 2019. Anemia was defined according to World Health Organization Guidelines: Hematocrit<36% for women or <39% for men. Primary endpoint was 30-day AKI. Anemia's effect on AKI was determined using inverse probability weighted logistic regression.

RESULTS

There were 2275 OAR; mean age was 70.9 ± 8.2 y; 24.0% were women. Anemia was present in 498 (26.3%) patients; 165 (7.6%) had a hematocrit<33% and 8 (0.35%) had a hematocrit<24%. Differences in patient factor were nonsignificant after weighting. Any degree of postoperative AKI was more common in the anemia group (11.2% vs 5.1%; unweighted P < 0.001), as was AKI requiring hemodialysis (7.7% vs 3.2%; unweighted P < 0.001). In the weighted multivariable analysis, anemia was independently associated with postoperative AKI (odds ratio 1.51; 95% confidence interval: 1.01-2.26; P = 0.042) while controlling for age and operative factors. Patients with postoperative AKI were significantly more likely to die postoperatively than those without (26.1% vs 1.9%; <0.001).

CONCLUSIONS

Preoperative anemia was independently associated with post-OAR AKI after propensity weighting and controlling for operative factors. AKI is a major source of morbidity and mortality in these patients, and, if time permits, preoperative correction of anemia or its underlying cause should be considered in high-risk patients.

Selection criterion for endovascular aortic repair in those with chronic kidney disease

OBJECTIVE

Endovascular aortic repair (EVAR) is the preferred method of repair for abdominal aortic aneurysms (AAAs). However, patients with advanced chronic kidney disease (CKD) are a high-risk group, and it is unknown which patients with CKD benefit from EVAR vs continued surveillance. The purpose of this study was to identify which patients with advanced CKD may benefit from EVAR.

METHODS

The Vascular Quality Initiative Database was utilized to identify elective EVARs for AAAs. Patients were excluded if they underwent urgent or emergent repairs. CKD stages were categorized based on preoperative estimated glomular filtration rate (eGFR) and dialysis status. Predicted 1-year mortality of untreated AAAs was calculated by modifying a validated comorbidity score that predicts 1-year mortality (Gagne Index) without repair. The primary outcome was actual 1-year mortality, which was compared with the predicted 1-year mortality without repair.

RESULTS

A total of 34,926 patient met study criteria. There were differences in Gagne Indices among the varying classes of CKD. Patients with CKD 4 and CKD 5 had the highest 1-year mortality rates, followed by CKD 3b, which was significantly higher than those with CKD 1 and CKD 2. Patients with CKD 4 had no differences between actual 1-year mortality with EVAR and predicted 1-year survival without EVAR across all AAA sizes. Those with CKD 5 had worse actual 1-year survival with EVAR than predicted 1-year survival without EVAR for AAAs <5.5 cm. Patients with CKD 5 only experienced an actual mortality benefit with EVAR compared with predicted 1-year mortality without EVAR for AAAs ≥7.0 cm.

CONCLUSION

The current data suggest that patients with CKD 3b, 4, and 5 represent a high-risk group who may not benefit from elective EVAR utilizing traditional size criteria. Patients with CKD 4 and 5 with AAAs <5.5 cm do not benefit from elective EVAR. In patients with CKD 5, elective EVAR may need to be reserved for AAAs ≥7.0 cm unless there are other concerning anatomic characteristics.

Postoperative Intensive Care Management of Aortic Repair

Vascular surgery patients have multiple comorbidities and are at high risk for perioperative complications. Aortic repair surgery has greatly evolved in recent years, with an increasing predominance of endovascular techniques (EVAR). The incidence of cardiac complications is significantly reduced with endovascular repair, but high-risk patients require postoperative ST-segment monitoring. Open aortic repair may portend a prohibitive risk of respiratory complications that could be a contraindication for surgery. This risk is greatly reduced in the case of an endovascular approach, and general anesthesia should be avoided whenever possible in the case of endovascular repair. Preoperative renal function and postoperative kidney injury are powerful determinants of short- and long-term outcome, so that preoperative risk stratification and secondary prevention are critical tasks. Intraoperative renal protection with selective renal and distal aortic perfusion is essential during open repair. EVAR has lower rates of postoperative renal failure compared to open repair, with approximately half the risk for acute kidney injury (AKI) and one-third of the risk of hemodialysis requirement. Spinal cord ischemia used to be the most distinctive and feared complication of aortic repair. The risk has significantly decreased since the beginning of aortic surgery, with advances in surgical technique and spinal protection protocols, and is lower with endovascular repair. Endovascular repair avoids extensive aortic dissection and aortic cross-clamping and is generally associated with reduced blood loss and less coagulopathy. The intensive care physician must be aware that aortic repair surgery has an impact on every organ system, and the importance of early recognition of organ failure cannot be overemphasized.

Decreasing Trends in Reintervention and Readmission After Endovascular Aneurysm Repair in a Multiregional Implant Registry

OBJECTIVES

As endovascular aortic aneurysm repair (EVAR) matures into its third decade, measures such as long-term reintervention and readmission have become a focus of quality improvement efforts. Within a large United States integrated healthcare system, we describe time trends in the rates of long-term reinterventions utilization measures.

METHODS

Data from a US multiregional EVAR registry was used to perform a descriptive study of 3,891 adults who underwent conventional infrarenal EVAR for infrarenal abdominal aortic aneurysm between 2010 to 2019. Three-year follow-up was 96.7%. Outcomes included 1-, 3-, and 5-year graft revision (defined as a procedure involving placement of a new endograft component), secondary interventions (defined as a procedure necessary for maintenance of EVAR integrity, e.g., coil embolization and balloon angioplasty/stenting), conversion to open, interventions for type II endoleaks alone, and 90-day readmission. Crude cause-specific reintervention probabilities were calculated by operative year using the Aalen-Johansen estimator, with death as a competing risk and December 31, 2020 as the study end date.

RESULTS

Excluding interventions for type II endoleak alone, 1-year secondary intervention incidence decreased from 5.9% for EVARs in 2010 to 2.0% in 2019 (p<0.001) and 3-year incidence decreased from 7.2% to 3.6% from 2010 to 2017 (p=0.03). The 3-year incidences of graft revision (mean incidence 3.4%) and conversion to open remained fairly stable (mean incidence 0.6%) over time. The 3-year incidence of interventions for type II endoleak alone also decreased from 3.4% in 2010 to 0.7% in 2017 (p=0.01). 90-day readmission rates decreased from 19.3% for index EVAR in 2010 to 9.2% in 2019 (p=0.03).

CONCLUSIONS

Comprehensive data from a multiregional healthcare system demonstrates decreasing long-term secondary intervention and readmission rates over time in patients undergoing EVAR. These trends are not explained by evolving management of type II endoleaks and suggest improving graft durability, patient selection or surgical technique. Further study is needed to define implant and anatomic predictors of different types of long-term reintervention.

Systematic Review and Meta-Analysis of Preventative Strategies for Acute Kidney Injury in Patients Undergoing Abdominal Aortic Aneurysm Repair

BACKGOUND

To assess the effect of various preventative interventions for reducing the incidence of postoperative acute kidney injury (AKI) in patients undergoing elective abdominal aortic aneurysm (AAA) repair.

METHODS

We included randomized controlled trials of 10 patients or more which tested a preventative intervention versus standard therapy or placebo in patients undergoing elective AAA repair using the open or endovascular approach. Studies including mixed patient populations such as those with aortic occlusive disease, thoracoabdominal aneurysms or ruptured aneurysms were ineligible for review. We searched Medline (1966-2019), EMBASE (1947-2019), CINAHL (1961-2019), Web of Science (1945-2019), Scopus (1966-2019), and The Cochrane Library (1996-2019) for trials available as published manuscripts in English. Study quality was assessed using the Cochrane Collaboration risk of bias tool. Where possible we pooled the results of similar interventions using random effects meta-analysis.

RESULTS

We included 17 trials involving 1443 participants. Most trials were small, single-center studies, with varying definitions of AKI and a high or moderate risk of bias. The preventative strategies with possible protective effects were mannitol, a composite of antioxidant supplements, an open extraperitoneal approach, and human atrial natriuretic peptide (hANP). Curcumin, methylprednisolone, carbon dioxide contrast medium, hemodynamic monitoring and N-acetylcysteine were found to be ineffective. Six trials with a total of 355 participants reported on remote ischemic preconditioning (RIPC) and our meta-analysis showed no statistically significant difference between RIPC and standard treatment (OR 1.20, 95% CI 0.37, 3.89); although the results should be interpreted with caution due to considerable statistical heterogeneity (I² = 70%). None of the interventions studied significantly reduced receipt of renal replacement therapy (RRT).

CONCLUSIONS

Interventions that have shown some potential to reduce AKI after AAA repair include mannitol, a composite of antioxidant supplements, an open extraperitoneal approach and hANP. These conclusions are limited by the small size, high risk of bias and inconsistency of the included trials. Large, high quality, multi-center randomized trials will help determine which interventions are effective in reducing the incidence of postoperative AKI among patients undergoing elective AAA repair.

Long-term outcomes of intervention between open repair and endovascular aortic repair for descending aortic pathologies: a propensity-matched analysis

BACKGROUND

The long-term complication rates of open repair and thoracic endovascular aortic repair (TEVAR) have not yet been determined. Therefore, this study aimed to compare the long-term outcomes and aortic reintervention rates between open repair and TEVAR in patients with descending thoracic aortic pathologies.

METHODS

Between January 2002 and December 2017, 230 patients with descending thoracic aortic pathologies underwent surgery. Of these, 136 patients were included in this retrospective study: 45 patients (10, 2, and 33 with dissection, penetrating atherosclerotic ulcer, and pseudoaneurysm, respectively) underwent open repair and 91 patients (27, 1, and 63 with dissection, penetrating atherosclerotic ulcer, and pseudoaneurysm, respectively) underwent TEVAR. The primary end points were in-hospital mortality, and short-term complications. The secondary end points were long-term mortality and reintervention rates. Based on the propensity score matching (PSM), 35 patients who underwent open repair were matched to 35 patients who underwent TEVAR (ratio = 1:1).

RESULTS

The mean follow-up period was 70.2 ± 51.9 months. Shorter intensive care unit and hospital stay were seen in the TEVAR group than in the open repair group before and after PSM (p < 0.001 and p < 0.001, respectively). However, in-hospital mortality, and spinal cord ischemia were not significantly different among the two groups (before PSM: p = 0.068 and p = 0.211, respectively; after PSM: p = 0.303 and p = 0.314, respectively). The cumulative all-cause death and aorta-related death showed no significant differences between the two groups (before PSM: p = 0.709 and p = 0.734, respectively; after PSM: p = 0.888 and p = 0.731, respectively). However, aortic reintervention rates were higher in the TEVAR group than in the open repair group before and after PSM (p = 0.006 and p = 0.013, respectively).

CONCLUSION

The TEVAR group was superior in short-term recovery outcomes but had higher reintervention rates compared to the open repair group. However, there were no significant differences in long-term survival between the two groups.

Endograft type and anesthesia mode are associated with mortality of endovascular aneurysm repair for ruptured abdominal aortic aneurysms

OBJECTIVE

Endovascular aneurysm repair has become the primary treatment modality for ruptured infrarenal abdominal aortic aneurysm. This study examines the impact of endograft type on perioperative outcomes for ruptured infrarenal abdominal aortic aneurysm.

METHOD

The targeted endovascular aneurysm repair files of the American College of Surgeons National Surgical Quality Improvement Program database (2012-2017) were used. Only patients treated for ruptured infrarenal abdominal aortic aneurysm were included. All patients requiring concomitant stenting of the visceral arteries or aneurysmal iliac arteries or open abdominal surgery were excluded. The characteristics of patients treated with the different endografts and the corresponding outcomes were compared using Stata software.

RESULTS

There were 479 patients treated with the three most common endografts: Cook Zenith (n = 127), Gore Excluder (n = 239), and Medtronic Endurant (n = 113). The number of other endografts was too small for statistical analysis. Compared to patients treated with Excluder or Endurant, the patients treated with Zenith had significantly lower body mass index (P < .001) and were less likely to be white (P < .001). On the other hand, patients treated with Endurant were less likely to be smoker (P = .016). Patients treated with Zenith had significantly larger ruptured infrarenal abdominal aortic aneurysm diameter (P = .045). The overall mortality was 18% and morbidity 74.3%. There was a statistically significant difference in overall mortality (Zenith = 11.8%, Excluder = 18%, Endurant = 24.8%, P = .033) but not morbidity (P = .808) between the three groups. Post hoc analysis for overall mortality showed only significant difference between Zenith and Endurant. The difference in mortality was not significant in patients presenting with ruptured infrarenal abdominal aortic aneurysm without hypotension (P = .065). On multivariable analysis, treatment with the Endurant endograft was associated with increased mortality compared to Zenith (odds ratio = 3.0 [confidence interval 1.31-6.7]). General anesthesia (odds ratio = 2.67 [confidence interval 1.02-7.02]), rupture with hypotension (odds ratio = 4.49 [confidence interval 2.54-7.95]), and dependent functional status (odds ratio = 5.7 [confidence interval 1.96-16.59]) were independently associated with increased mortality while increasing body mass index (odds ratio = 0.97 [confidence interval 0.95-0.99]) was associated with reduced risk of mortality.

CONCLUSIONS

This study highlights contemporary outcomes of endovascular aneurysm repair for ruptured infrarenal abdominal aortic aneurysm with relatively low mortality. Endograft type and anesthesia technique are modifiable factors that can potentially improve outcomes. Significant variation in the outcomes of the different endografts warrants further research.

The effect of Endovascular Aneurysm Repair on Renal Function in Patients Treated for Abdominal Aortic Aneurysm

Aim:

The effect of endovascular aneurysm repair in patients treated for abdominal aortic aneurysm has not been clearly defined. The objective of the present article was to provide a contemporary literature review and perform an analysis to determine the effect of EVAR on renal function in the early post-operative period and during follow-up.

Methods:

A systematic review of the literature was undertaken to identify all studies reporting the effect of EVAR on renal function. Outcome data were pooled and combined overall effect sizes were calculated using fixed or random-effects models.

Results:

Thirty-two studies reporting on 24846 patients were included. Acute renal failure after EVAR occurred with an estimated frequency of 9% (95%CI: 5-16%; I2=97%). Median follow-up period was 19.5 months (range 1-60 months). The estimated frequency of chronic renal failure during follow-up was 7% (95%CI: 3-17%; I2=98%). Hemodialysis was required in 2% (1-3%; I2=97%) of the cases.

Conclusion:

High-level evidence demonstrating the effect of EVAR on the incidence of acute and chronic renal failure is lacking. Based on the current available data, nearly 10% of patients undergoing EVAR for AAA have an increased risk for renal dysfunction after the procedure. Whether this deterioration may lead to a worse outcome has not been adequately proved.

Meta-analysis of long-term survival after elective endovascular or open repair of abdominal aortic aneurysm

BACKGROUND

Endovascular aneurysm repair (EVAR) has become the preferred strategy for elective repair of abdominal aortic aneurysm (AAA) for many patients. However, the superiority of the endovascular procedure has recently been challenged by reports of impaired long-term survival in patients who underwent EVAR. A systematic review of long-term survival following AAA repair was therefore undertaken.

METHODS

A systematic review was performed according to PRISMA guidelines. Articles reporting short- and/or long-term mortality of EVAR and open surgical repair (OSR) of AAA were identified. Pooled overall survival estimates (hazard ratios (HRs) with corresponding 95 per cent c.i. for EVAR versus OSR) were calculated using a random-effects model. Possible confounding owing to age differences between patients receiving EVAR or OSR was addressed by estimating relative survival.

RESULTS

Some 53 studies were identified. The 30-day mortality rate was lower for EVAR compared with OSR: 1·16 (95 per cent c.i. 0·92 to 1·39) versus 3·27 (2·71 to 3·83) per cent. Long-term survival rates were similar for EVAR versus OSR (HRs 1·01, 1·00 and 0·98 for 3, 5 and 10 years respectively; P = 0·721, P = 0·912 and P = 0·777). Correction of age inequality by means of relative survival analysis showed equal long-term survival: 0·94, 0·91 and 0·76 at 3, 5 and 10 years for EVAR, and 0·96, 0·91 and 0·76 respectively for OSR.

CONCLUSION

Long-term overall survival rates were similar for EVAR and OSR. Available data do not allow extension beyond the 10-year survival window or analysis of specific subgroups.

Comparative study of clinical outcome of endovascular aortic aneurysms repair in large diameter aortic necks (>31 mm) versus smaller necks

BACKGROUND

This study compares short-term (30 days) and intermediate term (3 years) clinical outcomes in patients with large (≥31 mm) versus small aortic neck diameters (≤28 and ≤31 mm).

METHODS

Prospectively collected data from 741 patients who underwent endovascular aortic aneurysm repair were analyzed. Some surgeons have reported the threshold for a large aortic neck for endovascular aortic aneurysm repair to be 28 mm, whereas for others it is 31 mm. Therefore, we classified aortic neck diameter into less than or equal to 28 versus greater than 28 mm; and less than or equal to 31 versus greater than 31 mm. Logistic regression and Kaplan-Meier analyses were used to compare outcomes.

RESULTS

There were 688 patients who had a defined aortic neck diameter: 592 with less than or equal to 28 mm, 96 with greater than 28 mm, 655 with less than or equal to 31 mm, and 33 with greater than 31 mm. The mean follow-up was 25.2 months for less than or equal to 31 mm versus 31.8 months for greater than 31 mm. Clinical characteristics were similar in all groups, except that there were more patients outside the instructions for use in the greater than 31 mm versus less than or equal to 31 mm group (94% vs 44%; P < .0001). There was a significant increase in early type I endoleak for patients with an aortic neck diameter of greater than 31 versus less than or equal to 31 mm (9 [27%] vs 74 [11%]; P = .01); late type I endoleaks (4 [14%] vs 18 [3%]; P = .01); sac expansion (5 [17%] vs 28 [5%]; P = .01); late intervention (5 [17%] vs 23 [4%]; P = .01); and death (9 [31%] vs 48 [8%]; P < .0001). There were no differences in outcomes between the patients with greater than 28 mm aortic neck diameters and the less than or equal to 28 mm diameters. Freedom from late type I endoleak at 1, 2, and 3 years were 96%, 88%, and 88% for patients with a neck diameter of greater than 31 mm versus 97%, 97%, and 97% for a diameter less than or equal to 31 mm (P = .19). The rate of freedom from sac expansion for patients with a diameter greater than 31 mm was 88%, 81%, and 81% at 1, 2, and 3 years versus 99%, 97%, and 92% for a diameter less than or equal to 31 mm (P = .02). Freedom from late intervention for 1, 2, and 3 years for patients with a diameter greater than 31 mm were 91%, 91%, and 91% versus 99%, 97%, and 96% for those with a diameter less than or equal to 31 mm. Survival rates at 1, 2, and 3 years for a diameter greater than 31 mm were 83%, 74%, and 68% versus 96%, 92%, and 90% for a diameter less than or equal to 31 mm (P < .001). Multivariate logistic regression analysis showed that patients with a diameter greater than 31 mm had an odds ratio of 6.1 (95% confidence interval [CI], 2.2-16.8) for mortality, 4.7 (95% CI, 1.4-15.5) for sac expansion, and 4.9 (95% CI, 1.4-17.4) for late type I endoleak.

CONCLUSIONS

Patients with large aortic neck diameters (>31 mm) had higher rates of early and late type I endoleak, sac expansion, late intervention, and mortality.

Complications and Perioperative Management of Patients Undergoing Thoracic Endovascular Aortic Repair

Endovascular treatments have become increasingly common for patients with a variety of thoracic aortic pathologies. Although considered less invasive than traditional open surgical approaches, they are nonetheless complex procedures. Patients undergo manipulation of an often calcified aorta near the origin of the carotid and subclavian vessels and have stents placed in a curved vessel adjacent to a perpetually beating heart. These stents can obstruct blood flow to the spinal cord, induce an inflammatory response, and in rare cases erode into the adjacent trachea or esophagus. Renal complications range from contrast-induced nephropathy to hypotension and ischemia to dissection. Emboli can lead to strokes and mesenteric ischemia. These patients have complex medical histories, and skilled perioperative management is critical to achieving the best clinical outcomes. Here, we review the medical management of the most common complications in these patients including stroke, spinal cord ischemia, renal injury, retrograde dissections, aortoesophageal and aortobronchial fistulas, postimplantation syndrome, mesenteric ischemia, and endograft failure.

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.

Functional status predicts major complications and death after endovascular repair of abdominal aortic aneurysms

OBJECTIVE

Endovascular aneurysm repair (EVAR) is considered a lower risk option for treating abdominal aortic aneurysms and is of particular utility in patients with poor functional status who may be poor candidates for open repair. However, the specific contribution of preoperative functional status to EVAR outcomes remains poorly defined. We hypothesized that impaired functional status, based simply on the ability of patients to perform activities of daily living, is associated with worse outcomes after EVAR.

METHODS

Patients undergoing nonemergent EVAR for abdominal aortic aneurysm between 2010 and 2014 were identified in the National Surgical Quality Improvement Program (NSQIP) database. The primary outcomes were 30-day mortality and major operative and systemic complications. Secondary outcomes were inpatient length of stay, need for reoperation, and discharge disposition. Using the NSQIP-defined preoperative functional status, patients were stratified as independent or dependent (either partial or totally dependent) and compared by univariate and multivariable analyses.

RESULTS

Of 13,432 patients undergoing EVAR between 2010 and 2014, 13,043 were independent (97%) and 389 were dependent (3%) before surgery. Dependent patients were older and more frequently minorities; had higher rates of chronic pulmonary, heart, and kidney disease; and were more likely to have an American Society of Anesthesiologists score of 4 or 5. On multivariable analysis, preoperative dependent status was an independent risk factor for operative complications (odds ratio [OR], 3.1; 95% confidence interval [CI], 2.5-3.9), systemic complications (OR, 2.8; 95% CI, 2.0-3.9), and 30-day mortality (OR, 3.4; 95% CI, 2.1-5.6). Secondary outcomes were worse among dependent patients.

CONCLUSIONS

Although EVAR is a minimally invasive procedure with substantially less physiologic stress than in open aortic repair, preoperative functional status is a critical determinant of adverse outcomes after EVAR in spite of the minimally invasive nature of the procedure. Functional status, as measured by performance of activities of daily living, can be used as a valuable marker of increased perioperative risk and may identify patients who may benefit from preoperative conditioning and specialized perioperative care.

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.

Anesthetic considerations for endovascular abdominal aortic aneurysm repair

Aneurysm is defined as a localized and permanent dilatation with an increase in normal diameter by more than 50%. It is more common in males and can affect up to 8% of elderly men. Smoking is the greatest risk factor for abdominal aortic aneurysm (AAA) and other risk factors include hypertension, hyperlipidemia, family history of aneurysms, inflammatory vasculitis, and trauma. Endovascular Aneurysm Repair [EVAR] is a common procedure performed for AAA, because of its minimal invasiveness as compared with open surgical repair. Patients undergoing EVAR have a greater incidence of major co-morbidities and should undergo comprehensive preoperative assessment and optimization within the multidisciplinary settings. In majority of cases, EVAR is extremely well-tolerated. The aim of this article is to outline the Anesthetic considerations related to EVAR.

Institutional Cost of Unplanned 30-Day Readmission Following Open and Endovascular Surgery

Background:

Vascular surgical patients have a high rate of readmission, and the cost of readmission for these patients has not been described. Herein, we characterize and compare institutional index hospitalization and 30-day readmission cost following open and endovascular vascular procedures.

Methods:

The American College of Surgeons National Surgical Quality Improvement Program database was used to identify inpatient open and endovascular procedures at a single institution, from January 2011 through June 2012. Variable and fixed costs for index hospitalization and unplanned 30-day readmissions were obtained using SAP BusinessObjects. Patient characteristics and outcome variables were analyzed using Student t tests or Wilcoxon rank-sum nonparametric tests for continuous variables and Fisher exact tests for categorical variables.

Results:

One thousand twenty-six inpatient procedures were included in the analysis. There were 605 (59%) open and 421 (41%) endovascular procedures with a 30-day unplanned readmission rate of 16.9% and 17.8%, respectively ( P = .679). The mean index hospitalization costs for open and endovascular procedures were US$27 653 and US$23 999, respectively ( P = .146). The mean costs for 30-day unplanned readmission for open and endovascular procedures were US$19 117 and US$17 887, respectively ( P = .635). Among open procedures, the mean cost for patients not readmitted was US$28 321 compared to US$31 115 for those readmitted ( P = .003). Among endovascular procedures, the mean cost for patients not readmitted was US$26 908 compared to US$32 262 for those readmitted ( P = .028).

Conclusion:

The cost of index hospitalization and 30-day unplanned readmission are similar for open and endovascular procedures. Readmitted patients had a higher mean index hospitalization cost irrespective of open or endovascular procedure.

Clinical Impact of Chronic Renal Insufficiency on Endovascular Aneurysm Repair

Endovascular aneurysm repair of abdominal aortic aneurysms has become a viable alternative to open repair. A significant proportion of this patient population has chronic renal insufficiency. The surgical outcomes associated with endovascular repair in 342 patients, with and without chronic renal insufficiency, are reported. Perioperative mortality, length of admission, length of intensive care unit admission, and rates of acute renal failure, congestive heart failure, myocardial infarction, conversion to open surgery, progression to hemodialysis, and incidence of endoleaks were retrospectively reviewed and analyzed. Endovascular repair demonstrated higher rates of acute renal failure, longer length of stay, and longer intensive care unit admissions in patients with chronic renal insufficiency. Patients with severe renal dysfunction demonstrated markedly elevated mortality and morbidity. These results indicate that chronic renal insufficiency is not an absolute contraindication to endovascular repair in patients with moderate renal dysfunction, but patients with severe renal dysfunction perform poorly after aortic reconstruction.

Functional status as a predictor of outcomes in open and endovascular abdominal aortic aneurysm repair

BACKGROUND

Functional status is a simple and rapidly assessable metric that may be used as a predictor for surgical outcomes. This study examined the association of functional status with short-term mortality after abdominal aortic aneurysm (AAA) repair in octogenarians to characterize the utility of functional status as a means of preoperative risk assessment.

METHODS

All patients who underwent endovascular and open AAA repair from 2002 to 2010 within the Veterans Affairs Surgical Quality Improvement Program (VASQIP) database were identified. Functional status, defined as an ordinal scale from 1 to 3 (1, independent; 2, partially dependent; 3, totally dependent), was examined using multivariate regression models with 30-day mortality as the primary outcome. For the purpose of analysis, this 3-point scale was converted into a binomial scale of function, with "normal" including 1 (completely independent) and "abnormal" including 2 or 3 (partially to totally dependent).

RESULTS

We identified 9030 patients who underwent AAA repair (46.6% open and 53.4% endovascular). Mortality at 30 days was 2.8% for the entire cohort (4.2% open, 1.7% endovascular; P < .001). There were 1340 patients aged ≥80 years, of which 67.3% underwent endovascular AAA repair. Among all age groups, functional status was a significant predictor of 30-day mortality (<80 years, P < .001; ≥80 years, P < .001). The ≥80 cohort with abnormal function status also demonstrated increased operative mortality (P = .002), length of stay (P = .001), and incidence of pulmonary complications (P = .025) compared with the cohort with normal functional status. Multivariate logistic regression demonstrated that within the ≥80-year-old cohort, only functional status remained a significant predictor of mortality (P < .001). In addition, the strength of the association between functional status and mortality was greater in the older cohort than in the younger one (Cox regression hazard ratio: 3.13 vs 2.18).

CONCLUSIONS

Functional status is a simple and rapidly applicable predictor of mortality within AAA patients and may be a useful tool to help preoperatively risk-stratify elderly patients presenting with AAA in need of repair. Further studies are needed to understand how best to apply these data to the clinical setting to guide preoperative decision making.

Risk factors for early renal dysfunction following endovascular aortic aneurysm repair and its effect on the postoperative outcome

PURPOSE

Renal insufficiency is associated with increased morbidity and death after endovascular aortic aneurysm repair (EVAR). However, the effect of postoperative acute kidney dysfunction on patient outcome has not been fully determined. This study aimed to determine the risk factors of early postoperative renal function decline using chronic kidney disease (CKD) staging and its effect on the clinical outcome.

METHODS

A retrospective analysis was performed on a prospectively maintained EVAR database. Pre- and postoperative CKD stages were determined for all patients according to the estimated glomerular filtration rate values.

RESULTS

We identified 135 patients who were treated with elective EVAR. CKD stage decline was observed in 25 (19 %) of the patients. Freedom from aneurysm-related death was significantly lower in patients with postoperative CKD progression compared with those with unchanged CKD stage. A shaggy aorta without oral beta-blocker administration and higher preoperative serum creatinine levels (>1.4 mg/dL) were found to be independent predictors of an early postoperative CKD stage decline.

CONCLUSIONS

Patients with postoperative CKD progression have an increased frequency of aneurysm-related death. The presence of a shaggy aorta, absence of oral beta-blocker administration and an increased preoperative creatinine level are independent predictors of early postoperative CKD progression.

Clinical registries and quality measurement in surgery: a systematic review

BACKGROUND

Surgical clinical registries provide clinical information with the intent of measuring and improving quality. This study aimed to describe how surgical clinical registries have been used to measure surgical quality, the reported findings, and the limitations of registry measurements.

METHODS

Medline, CINAHL, and Cochrane were queried for English articles with the terms: "registry AND surgery AND quality." Eligibility criteria were studies explicitly assessing quality measurement with registries as the primary data source. Studies were abstracted to identify registries, define registry structure, uses for quality measurement, and limitations of the measurements used.

RESULTS

A total of 111 studies of 18 registries were identified for data abstraction. Two registries were financed privately, and 5 registries were financed by a governmental organization. Across registries, the most common uses of process measures were for monitoring providers and as platforms for quality improvement initiatives. The most common uses of outcome measures were to improve quality modeling and to identify preoperative risk factors for poor outcomes. Eight studies noted improvements in risk-adjusted mortality with registry participation; one found no change. A major limitation is bias from context and means of data collection threatening internal validity of registry quality measurement. Conversely, the other major limitation is the cost of participation, which threatens the external validity of registry quality measurement.

CONCLUSION

Clinical registries have advanced surgical quality definition, measurement, and modeling as well as having served as platforms for local initiatives for quality improvement. The implication of this finding is that subsidizing registry participation may improve data validity as well as engage providers in quality improvement.

Incidence of Acute Kidney Injury (AKI) after Endovascular Abdominal Aortic Aneurysm Repair (EVAR) and Impact on Outcome

BACKGROUND

Acute kidney injury (AKI) is an important post-operative complication that may impact on mortality, morbidity, and cost. The incidence after endovascular aneurysm repair (EVAR) remains unknown, as the current literature has not employed consistent definitions. The aim of this study is to assess the incidence of AKI after elective EVAR and examine the impact of AKI on mortality and cardiovascular morbidity using the current universally accepted definitions.

METHODS

This was a cohort study using prospectively collected data, including consecutive patients undergoing elective EVAR for an infrarenal abdominal aortic aneurysm (AAA). Those with end stage renal failure were excluded. The primary endpoint was incidence of AKI as per the "Acute Kidney Injury Network" (AKIN), and "Kidney Disease Improving Global Outcomes" (KDIGO) criteria. Secondary endpoints included AKI stage, drop in estimated glomerular filtration rate (eGFR), and mortality and cardiovascular morbidity.

RESULTS

149 patients were included (16 females, 11%; mean age: 69 ± 8 years; mean AAA diameter: 6.0 ± 1.1 cm), 28 (18.8%) of whom developed AKI (26 patients classified as stage 1 and 2 as stage 2). Within 48 hours, those with AKI dropped their eGFR from 61 ± 20 mL/kg/1.73 m(2) to 51 ± 20 units (p < .001), and those without from 75 ± 9 to 74 ± 10 units (p < .001). None required dialysis during a 33 ± 11 month follow up. Development of AKI was associated with mortality (HR 0.035, 95% CI: 0.005 to 0.240, p < .001) and cardiovascular morbidity (HR: 0.021, 95% CI: 0.004 to 0.11, p < .001) on adjusted regression analysis.

CONCLUSIONS

The incidence of AKI after EVAR is significant and is independently associated with medium-term mortality and morbidity.

A multiregional registry experience using an electronic medical record to optimize data capture for longitudinal outcomes in endovascular abdominal aortic aneurysm repair

OBJECTIVE

Registries have been proven useful to assess clinical outcomes, but data entry and personnel expenses are challenging. We developed a registry to track patients undergoing endovascular aortic aneurysm repair (EVAR) in an integrated health care system, leveraging an electronic medical record (EMR) to evaluate clinical practices, device performance, surgical complications, and medium-term outcomes. This study describes the registry design, data collection, outcomes validation, and ongoing surveillance, highlighting the unique integration with the EMR.

METHODS

EVARs in six geographic regions of Kaiser Permanente were entered in the registry. Cases were imported using a screening algorithm of inpatient codes applied to the EMR. Standard note templates containing data fields were used for surgeons to enter preoperative, postoperative, and operative data as part of normal workflows in the operating room and clinics. Clinical content experts reviewed cases and entered any missing data of operative details. Patient comorbidities, aneurysm characteristics, implant details, and surgical outcomes were captured. Patients entered in the registry are followed up for life, and all relevant events are captured.

RESULTS

Between January 2010 and June 2013, 2112 procedures were entered in the registry. Surgeon compliance with data entry ranges from 60% to 90% by region but has steadily increased over time. Mean aneurysm size was 5.9 cm (standard deviation, 1.3). Most patients were male (84%), were hypertensive (69%), or had a smoking history (79%). The overall reintervention rate was 10.8%: conversion to open repair (0.9%), EVAR revision (2.6%), other surgical intervention (7.3%). Of the reinterventions, 27% were for endoleaks (I, 34.3%; II, 56.9%; III, 8.8%; IV and V, 0.0%), 10.5% were due to graft malfunction, 3.4% were due to infection, and 2.3% were due to rupture.

CONCLUSIONS

Leveraging an EMR provides a robust platform for monitoring short-term and midterm outcomes after abdominal aortic aneurysm repair. Use of standardized templates in the EMR allows data entry as part of normal workflow, improving compliance, accuracy, and data capture using limited but expert personnel. Assessment of patient demographics, device performance, practice variation, and postoperative outcomes benefits clinical decision-making by providing complete and adjudicated event reporting. The findings from this large, community-based EVAR registry augment other studies limited to perioperative and short-term outcomes or small patient cohorts.

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

Deterioration in renal function has been described after endovascular repair of abdominal aortic aneurysms (EVRs). The etiology is multifactorial and represents an important therapeutic target. A need exists to quantitatively summarize incidence and severity of renal dysfunction after EVR to allow better-informed attempts to preserve renal function and improve life expectancy. Here a systematic search was performed using Medline and Embase for renal function after EVR applying PRISMA statements. Univariate and multivariate random-effects meta-analyses were performed to estimate pooled postoperative changes in serum creatinine and creatinine clearance at four time points after EVR. Clinically relevant deterioration in renal function was also estimated at 1 year or more after EVR. Pooled probability of clinically relevant deterioration in renal function at 1 year or more was 18% (95% confidence interval of 14-23%, I2 of 82.5%). Serum creatinine increased after EVR by 0.05 mg/dl at 30 days/1 month, 0.09 mg/dl at 1 month to 1 year, and 0.11 mg/dl at 1 year or more (all significant). Creatinine clearance decreased after EVR by 5.65 ml/min at 1 month-1 year and by 6.58 ml/min at 1 year or more (both significant). Thus, renal dysfunction after EVR is common and merits attention.

Optimal perioperative medical management of the vascular surgery patient

Perioperative medical management of patients undergoing vascular surgery can be challenging because they represent the surgical population at highest risk. β-Blockers should be continued perioperatively in patients already taking them preoperatively. Statins may be used in the perioperative period in patients who are not on statin therapy preoperatively. Institutional guidelines should be used to guide insulin replacement. Recent research suggests that measurement of troponins may provide some risk stratification in clinically stable patients following vascular surgery. Multimodal pain therapy including nonopioid strategies is necessary to improve the efficacy of pain relief and decrease the risk of side effects and complications.

Limited survival in dialysis patients undergoing intact abdominal aortic aneurysm repair

OBJECTIVE

Elective abdominal aortic aneurysm (AAA) repair in suitable candidates is a standard modality. The outcomes of AAA repair in patients with end-stage renal disease on dialysis are not well characterized, and there is questionable survival advantage in such patients with limited life expectancy. We sought to describe outcomes after AAA repair in U.S. dialysis patients.

METHODS

The United States Renal Data System was used to collect data on intact asymptomatic AAA repair procedures in dialysis patients in the United States between 2005 and 2008. Endovascular AAA repair (EVAR) and open aortic repair (OAR) were identified by Current Procedural Terminology codes. Primary outcomes were perioperative (30-day) mortality and long-term survival. Predictors of mortality were identified by multivariate regression models.

RESULTS

A total of 1557 patients were identified who had undergone elective AAA repair: 261 OAR and 1296 EVAR. The 30-day mortality was 11.3% (EVAR, 10.3%; OAR, 16.1%; P = .010), with increased age associated with increased mortality (odds ratio, 1.04; 95% confidence interval [CI], 1.02-1.07; P = .001). Kaplan-Meier survival estimates were 66.5% at 1 year (EVAR, 66.2%; OAR, 68%) and 37.4% at 3 years (EVAR, 36.8%; OAR, 40%; P = .33). Median survival was 25.3 months after EVAR and 27.4 months after OAR. Women had a higher mortality rate at 1 year (38.7%) compared with men (32.0%) (P = .015). There was no significant mortality difference at 1 year in comparing type of procedure in both men (EVAR, 31.6%; OAR, 34%; P = .55) and women (EVAR, 39.3%; OAR, 36%; P = .60). A Cox proportional hazards model demonstrated that male gender (hazard ratio [HR], 0.75; 95% CI, 0.62-0.92; P = .005), increased time on dialysis (HR for each year on dialysis, 0.79; 95% CI, 0.75-0.83; P < .001), kidney transplantation history (HR, 0.62; 95% CI, 0.43-0.88; P = .008), and diagnosis of hypertension (HR, 0.60; 95% CI, 0.48-0.75; P < .001) were protective against mortality. Increased age (HR, 1.02; 95% CI, 1.01-1.03; P < .001) and diabetes diagnosis (HR, 1.39; 95% CI, 1.13-1.71; P = .002) predicted increased mortality.

CONCLUSIONS

AAA patients on dialysis have high perioperative and 1-year mortality rates after EVAR or OAR, particularly diabetics, women, and the elderly. This raises questions about the indications for intact AAA repair in dialysis patients, in whom the size threshold may need to be raised. Dialysis patients may be best served by deferring repair of AAA until AAAs reach large size or become symptomatic, especially if OAR is required, given the higher perioperative mortality compared with EVAR.

Grey relational analysis of benefit of surgical management for abdominal aortic aneurysm

Grey relational analysis was used to compare the long-term outcomes of endovascular repair (EVAR) versus open repair for patients with abdominal aortic aneurysm (AAA). Patients with AAA undergoing open repair (n = 133) or EVAR (n = 88) from July 1995 to January 2009 were studied retrospectively. Compared with EVAR, longer periods of postoperative intubation and hospital stay (P < 0.001) were required for open repair. The operation time was significantly longer in open surgery than in EVAR (P < 0.001). Patients in the open repair group required larger volumes of intraoperative blood transfusion than those in EVAR (P < 0.001), and they had more of a trend of cardiac failure after surgery than those in the EVAR group. The operative mortality was similar in both groups. On follow-up, the all-cause mortality and the rates of ischemic legs within 5 years had no significant differences between the 2 procedures (P > 0.05). The grey relational grades in EVAR and open repair were 0.673 and 0.936, respectively. Compared with open repair, patients with AAAs undergoing EVAR had fewer complications in the short term and had a similar all-cause mortality in the long term.

Grey relational analysis of benefit of surgical management for abdominal aortic aneurysm

Grey relational analysis was used to compare the long-term outcomes of endovascular repair (EVAR) versus open repair for patients with abdominal aortic aneurysm (AAA). Patients with AAA undergoing open repair (n = 133) or EVAR (n = 88) from July 1995 to January 2009 were studied retrospectively. Compared with EVAR, longer periods of postoperative intubation and hospital stay (P < 0.001) were required for open repair. The operation time was significantly longer in open surgery than in EVAR (P < 0.001). Patients in the open repair group required larger volumes of intraoperative blood transfusion than those in EVAR (P < 0.001), and they had more of a trend of cardiac failure after surgery than those in the EVAR group. The operative mortality was similar in both groups. On follow-up, the all-cause mortality and the rates of ischemic legs within 5 years had no significant differences between the 2 procedures (P > 0.05). The grey relational grades in EVAR and open repair were 0.673 and 0.936, respectively. Compared with open repair, patients with AAAs undergoing EVAR had fewer complications in the short term and had a similar all-cause mortality in the long term.

Risk factors for protracted postoperative length of stay after lower extremity bypass for critical limb ischemia

BACKGROUND

Compared with other common chronic conditions, admissions for management of peripheral arterial disease (PAD) are associated with prolonged hospitalizations. Length of stay (LOS) is one of many metrics receiving increased attention in the current focus on efficient healthcare delivery. Our objective was to characterize LOS among patients with severe PAD, those undergoing surgical bypass for critical limb ischemia (CLI), and identify risk factors for protracted postoperative LOS.

METHODS

Patient data from the 2007 to 2009 American College of Surgeons National Surgical Quality Improvement Program were used to develop a database consisting of patients undergoing bypass surgery for CLI (n = 4,894). Protracted postoperative LOS was defined as the top quartile of days hospitalized from surgery to discharge. Preoperative risk factors with significant association (Pearson chi-squared test; P < 0.05) were used to develop a logistic regression model for protracted postoperative LOS.

RESULTS

Average postoperative LOS was 7.5 days (median 6 days). The top quartile of postoperative LOS, >8 days, was used to define protracted LOS. Independent preoperative risk factors for protracted postoperative LOS included demographic characteristics (advanced age and non-Caucasian race), comorbidities, and medical history (e.g., obesity, dialysis dependence, severe cardiac and pulmonary disease, and bleeding disorders). Indicators of PAD severity (e.g., distal target sites, open wounds or gangrene, and prior arterial surgery) were also independent predictors of protracted LOS after surgery. The greatest predictors of extended postoperative LOS were prolonged preoperative hospitalization (OR 2.2 [95% CI: 1.8-2.6], P < 0.001) and preoperative dependent functional status (OR 2.0 [95% CI: 1.7-2.3], P < 0.001 for partial dependence; OR 2.8 [95% CI: 1.8-4.3], P < 0.001 for totally dependent status), where OR and CI stand for odds ratio and confidence interval.

CONCLUSIONS

Here, we identify preoperative risk factors for protracted postoperative LOS after infrainguinal bypass for CLI. These findings provide an important evidence basis for ongoing efforts to reduce healthcare spending and facilitate provision of efficient health care. Future efforts will include prospective identification of patients at high risk for protracted postoperative LOS and targeted multidisciplinary efforts to reduce associated costs without sacrificing healthcare quality.

Systematic review and meta-analysis of the early and late outcomes of open and endovascular repair of abdominal aortic aneurysm

Background

Any possible long-term benefit from endovascular (EVAR) versus open surgical repair for abdominal aortic aneurysm (AAA) remains unproven. Long-term data from the Open Versus Endovascular Repair (OVER) trial add to the debate regarding long-term all-cause and aneurysm-related mortality. The aim of this study was to investigate 30-day and long-term mortality, reintervention, rupture and morbidity after EVAR and open repair for AAA in a systematic review.

Methods

Standard PRISMA guidelines were followed. Random-effects Mantel–Haenszel meta-analysis was performed to evaluate mortality and morbidity outcomes.

Results

The existing published randomized trials, together with information from Medicare and SwedVasc databases, were included in a meta-analysis. This included 25 078 patients undergoing EVAR and 27 142 undergoing open repair for AAA. Patients who had EVAR had a significantly lower 30-day or in-hospital mortality rate (1·3 per cent versus 4·7 per cent for open repair; odds ratio (OR) 0·36, 95 per cent confidence interval 0·21 to 0·61; P &lt; 0·001). By 2-year follow-up there was no difference in all-cause mortality (14·3 versus 15·2 per cent; OR 0·87, 0·72 to 1·06; P = 0·17), which was maintained after at least 4 years of follow-up (34·7 versus 33·8 per cent; OR 1·11, 0·91 to 1·35; P = 0·30). There was no significant difference in aneurysm-related mortality by 2 years or longer follow-up. A significantly higher proportion of patients undergoing EVAR required reintervention (P = 0·003) and suffered aneurysm rupture (P &lt; 0·001).

Conclusion

There is no long-term survival benefit for patients who have EVAR compared with open repair for AAA. There are also significantly higher risks of reintervention and aneurysm rupture after EVAR.

Anesthesia-based evaluation of outcomes of lower-extremity vascular bypass procedures

BACKGROUND

This report examines the effects of regional versus general anesthesia for infrainguinal bypass procedures performed in the treatment of critical limb ischemia (CLI).

METHODS

Nonemergent infrainguinal bypass procedures for CLI (defined as rest pain or tissue loss) were identified using the 2005 to 2008 American College of Surgeons National Surgical Quality Improvement Program database using International Classification of Disease, ninth edition, and Current Procedure Terminology codes. Patients were classified according to National Surgical Quality Improvement Program data as receiving either general anesthesia or regional anesthesia. The regional anesthesia group included those specified as having regional, spinal, or epidural anesthesia. Demographic, medical, risk factor, operative, and outcomes data were abstracted for the study sample. Individual outcomes were evaluated according to the following morbidity categories: wound, pulmonary, venous thromboembolic, genitourinary, cardiovascular, and operative. Length of stay, total morbidity, and mortality were also evaluated. Associations between anesthesia types and outcomes were evaluated using linear or logistic regression.

RESULTS

A total of 5,462 inpatient hospital visits involving infrainguinal bypasses for CLI were identified. Mean patient age was 69 ± 12 years; 69% were Caucasian; and 39% were female. In all, 4,768 procedures were performed using general anesthesia and 694 with regional anesthesia. Patients receiving general anesthesia were younger and significantly more likely to have a history of smoking, previous lower-extremity bypass, previous amputation, previous stroke, and a history of a bleeding diathesis including the use of warfarin. Patients receiving regional anesthesia had a higher prevalence of chronic obstructive pulmonary disease. Tibial-level bypasses were performed in 51% of procedures, whereas 49% of procedures were popliteal-level bypasses. Cases performed using general anesthesia demonstrated a higher rate of resident involvement, need for blood transfusion, and operative time. There was no difference in the rate of popliteal-level and infrapopliteal-level bypasses between groups. Infrapopliteal bypass procedures performed using general anesthesia were more likely to involve prosthetic grafts and composite vein. Mortality occurred in 157 patients (3%). The overall morbidity rate was 37%. Mean and median lengths of stay were 7.5 days (± 8.1) and 6.0 days (Q1: 4.0, Q3: 8.0), respectively. Multivariate analyses demonstrated no significant differences by anesthesia type in the incidence of morbidity, mortality, or length of stay.

CONCLUSION

These results provide no evidence to support the systematic avoidance of general anesthesia for lower-extremity bypass procedures. These data suggest that anesthetic choice should be governed by local expertise and practice patterns.

Impact of chronic kidney disease on outcomes after abdominal aortic aneurysm repair

OBJECTIVE

Chronic kidney disease (CKD) is associated with increased morbidity and death after open abdominal aortic aneurysm (AAA) repair (OAR). This study highlights the effect of CKD on outcomes after endovascular AAA (EVAR) and OAR in contemporary practice.

METHODS

The National Surgical Quality Improvement Program (NSQIP) Participant Use File (2005-2008) was queried by Current Procedural Terminology (American Medical Association, Chicago, Ill) code to identify EVAR or OAR patients, who were grouped by CKD class as having mild (CKD class 1 or 2), moderate (CKD class 3), or severe (CKD class 4 or 5) renal disease. Propensity score analysis was performed to match OAR and EVAR patients with mild CKD with those with moderate or severe CKD. Comparative analysis of mortality and clinical outcomes was performed based on CKD strata.

RESULTS

We identified 8701 patients who were treated with EVAR (n = 5811) or OAR (n = 2890) of intact AAAs. Mild, moderate, and severe CKD was present in 63%, 30%, and 7%, respectively. CKD increased (P < .01) overall mortality, with rates of 1.7% (mild), 5.3% (moderate), and 7.7% (severe) in unmatched patients undergoing EVAR or OAR. Operative mortality rates in patients with severe CKD were as high as 6.2% for EVAR and 10.3% for OAR. Severity of CKD was associated with increasing frequency of risk factors; therefore, propensity matching to control for comorbidities was performed, resulting in similar baseline clinical and demographic features of patients with mild compared with those with moderate or severe disease. In propensity-matched cohorts, moderate CKD increased the risk of 30-day mortality for EVAR (1.9% mild vs 3.2% moderate; P = .013) and OAR (3.1% mild vs 8.4% moderate; P < .0001). Moderate CKD was also associated with increased morbidity in patients treated with EVAR (8.3% mild vs 12.8% moderate; P < .0001) or OAR (25.2% mild vs 32.4% moderate; P = .001). Similarly, severe CKD increased the risk of 30-day mortality for EVAR (2.6% mild vs 5.7% severe; P = .0081) and OAR (4.1% mild vs 9.9% severe; P = .0057). Severe CKD was also associated with increased morbidity in patients treated with EVAR (10.6% mild vs 19.2% severe; P < .0001) or OAR (31.1% mild vs 39.6% severe; P = .04).

CONCLUSIONS

The presence of moderate or severe CKD in patients considered for AAA repair is associated with significantly increased mortality and therefore should figure prominently in clinical decision making. The high mortality of AAA repair in patients with severe CKD is such that elective repair in such patients is not advised, except in extenuating clinical circumstances.

Clinical Results of Endovascular Abdominal Aortic Aneurysm Repair in Patients with Renal Insufficiency without Hemodialysis

OBJECTIVE

Chronic renal insufficiency may be a relative contraindication to endovascular aneurysm repair (EVAR) for the use of contrast enhanced mediums. It is thought that more contrast enhanced media are needed in patients who are not anatomically suitable for EVAR, because of procedural difficulties. We reviewed a 2 year EVAR experience at our institution to determine whether the procedure and use of contrast enhanced mediums has any deleterious effect on renal function in patients with pre-existing chronic renal insufficiency.

MATERIALS AND METHODS

EVAR was performed in 46 patients with pre-existing chronic renal insufficiency without hemodialysis. Patients were retrospectively assigned to two groups on the basis of their preoperative creatinine clearance levels. Furthermore, patients were assigned to two other groups on the basis of anatomical suitability for EVAR. The absolute change in the serum creatinine (Cr) level was reviewed in the each renal insufficiency group between the preoperative and post-operative time periods.

RESULTS

No increase in the serum Cr level was noted, and no patient required temporary or permanent hemodialysis, in any of the groups.

CONCLUSIONS

EVAR with contrast agents can be accomplished in patients with chronic renal insufficiency without hemodialysis; therefore,elevated Cr levels maynot be a contraindication in EVAR.