Designation as “Unfit for Open Repair” Is Associated With Poor Outcomes After Endovascular Aortic Aneurysm Repair

Assessment of fitness for open repair in patients with infrarenal abdominal aortic aneurysms

OBJECTIVE

Endovascular aortic repair (EVAR) was originally designed as a treatment modality for patients with abdominal aortic aneurysms (AAAs) deemed unfit for open repair. However, the definition of "unfit for open repair" is largely subjective and heterogenous. The purpose of this study was to compare patients deemed unfit for open repair who underwent EVAR to a matched cohort who underwent open repair for infrarenal AAAs.

METHODS

The Vascular Quality Initiative of the Society for Vascular Surgery was queried for patients who underwent EVAR and open infrarenal AAA repair from 2003 to 2022. Patients that underwent EVAR were included if they were deemed unfit for open repair by the operating surgeon. EVAR patients deemed unfit because of a hostile abdomen were excluded. Patients in both the open and EVAR datasets were excluded if their repair was deemed non-elective or if they had prior aortic surgery. EVAR patients were matched to a cohort of open patients. The primary outcome for this study was 1-year mortality. Secondary outcomes included 30-day mortality, major adverse cardiac events, pulmonary complications, non-home discharge, reinterventions, and 5-year survival.

RESULTS

A total of 5310 EVAR patients were identified who were deemed unfit for open repair. Of those, 3028 EVAR patients (57.0%) were able to be matched 1:1 to a cohort of open patients. Open patients had higher rates of major adverse cardiac events (20.2% vs 4.4%; P < .001), pulmonary complications (12.8% vs 1.6%; P < .001), non-home discharges (28.5% vs 7.9%; P < .001), and 30-day mortality (4.5% vs 1.4%; P < .001). There were no differences in early survival, but open repair had better middle and late survival compared with EVAR over the course of 5 years. A total of 74 EVAR patients (2.4%) had reinterventions during the study period. EVAR patients that required interventions had higher 1-year (40.5% vs 7.3%; P < .001) and 5-year mortality (43.2% vs 14.1%; P < .001) compared with those that did not require reinterventions. EVAR patients who had reinterventions had higher 1-year (40.5% vs 6.3%; P < .001) and 5-year (43.2% vs 20.3%; P = .006) mortality compared with their matched open cohort.

CONCLUSIONS

Patients undergoing EVAR for AAAs who are deemed unfit for open repair have better perioperative morbidity and mortality compared with open repair. However, patients who had an open repair had better middle and late survival over the course of 5 years. The categorization of unfitness for open surgery may be inaccurate and re-evaluation of this terminology/concept should be undertaken.

Impact of Previous Open Abdominal Surgery on Open Abdominal Aortic Repair: A Study from the NSQIP Database

BACKGROUND

While endovascular aneurysm repair has become a first-line strategy in many centers, open surgical repair (OSR) of abdominal aortic aneurysms (AAAs) is still the best option for certain patients. A significant number of patients who are offered OSR for AAA have been previously submitted to other open abdominal surgeries (PAS). It is unclear, however, how this may impact their outcomes. The purpose of this study was to determine if there is an association between PAS and outcomes of OSR of AAA.

METHODS

This is a retrospective cohort study based on clinical data from the American College of Surgeons National Surgical Quality Improvement Program database, including all patients undergoing elective OSR for AAA between 2011 and 2017. Excluded were patients with missing data on prior abdominal surgery, supramesenteric clamping, or urgent repairs. Patients with prior abdominal surgery (PAS) and patients without prior abdominal surgeries (nonPAS) were compared. The primary outcome was 30-day postoperative mortality. Secondary outcomes were operating time, ischemic colitis, postoperative complications, and lengths of hospital stay.

RESULTS

Of the 2034 patients included, 27% had previous open abdominal surgery and 73% did not. Overall, the median age was 71(interquartile range 65-76), 72% of patients were male, 44% were smokers, and the average body mass index was 27 kg/m2. Univariate analysis showed no difference in postoperative 30-day mortality (4.0% PAS vs. 4.1% nonPAS, P = 0.91) or overall postoperative complication rates (33% PAS vs. 29% nonPAS, P = 0.07). Previous open abdominal surgery was significantly associated with longer operating times (P = 0.032) and an almost doubled rate of ischemic colitis (4.7% PAS vs. 2.6% nonPAS, P = 0.02). Postoperative intensive care unit and hospitalization were also significantly longer in patients with prior abdominal surgery (P = 0.005 and P = 0.014, respectively). Finally, there were significantly less patients discharged home, as opposed to institutionalized care (75.7% PAS down from 82.4% nonPAS, P = 0.001). Despite these initial univariate analysis results, on multivariate analysis, PAS actually did not prove to be a statistically significant independent risk factor for 30-day mortality, ischemic colitis, or longer operating times.

CONCLUSIONS

This study suggests that patients who have undergone PAS may have some disadvantages in OSR of AAA. However, these negative trends do not go so far as to statistically significantly identify PAS as an independent risk factor for 30-day mortality, ischemic colitis, or longer operating times. As such, we suggest that a history of previous open abdominal surgery, in and of its own, should not exclude patients from consideration for open aortic abdominal aneurysm repair.

Machine learning to predict outcomes following endovascular abdominal aortic aneurysm repair

BACKGROUND

Endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) carries important perioperative risks; however, there are no widely used outcome prediction tools. The aim of this study was to apply machine learning (ML) to develop automated algorithms that predict 1-year mortality following EVAR.

METHODS

The Vascular Quality Initiative database was used to identify patients who underwent elective EVAR for infrarenal AAA between 2003 and 2023. Input features included 47 preoperative demographic/clinical variables. The primary outcome was 1-year all-cause mortality. Data were split into training (70 per cent) and test (30 per cent) sets. Using 10-fold cross-validation, 6 ML models were trained using preoperative features with logistic regression as the baseline comparator. The primary model evaluation metric was area under the receiver operating characteristic curve (AUROC). Model robustness was evaluated with calibration plot and Brier score.

RESULTS

Some 63 655 patients were included. One-year mortality occurred in 3122 (4.9 per cent) patients. The best performing prediction model for 1-year mortality was XGBoost, achieving an AUROC (95 per cent c.i.) of 0.96 (0.95-0.97). Comparatively, logistic regression had an AUROC (95 per cent c.i.) of 0.69 (0.68-0.71). The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.04. The top 3 predictive features in the algorithm were 1) unfit for open AAA repair, 2) functional status, and 3) preoperative dialysis.

CONCLUSIONS

In this data set, machine learning was able to predict 1-year mortality following EVAR using preoperative data and outperformed standard logistic regression models.

Insulin Dependence is Associated with Poor Long-Term Outcomes Following AAA Repair

BACKGROUND

While prior studies have confirmed the protective effect of diabetes on abdominal aortic aneurysm (AAA) development, much less is known about the effect of diabetes, and in particular insulin dependence, on outcomes following AAA repair. In this study, we aim to evaluate the role of insulin-dependent diabetes on short-term and long-term outcomes following open and endovascular AAA repair.

METHODS

The Vascular Implant Surveillance and Interventional Outcomes Network (VISION), a registry linking the Vascular Quality Initiative (VQI) data with Medicare claims, was queried for patients who underwent open or endovascular AAA repair from 2011 to the present. Exclusion criteria were unknown diabetes status, prior aortic intervention, maximum aneurysm diameter <45 mm at presentation, and Medicare Advantage coverage due to inconsistent follow-up. Patients were stratified based on diabetes status (no diabetes versus diabetes) and insulin dependence (no diabetes or non-insulin-dependent diabetes versus insulin-dependent diabetes).

RESULTS

Of the 38,437 cases in the VISION endovascular aortic aneurysm (EVAR) and open aortic aneurysm repair (OAR) databases, 21,943 met inclusion criteria. Perioperative outcomes after OAR were comparable between diabetic and nondiabetic patients. However, diabetic patients undergoing EVAR were significantly more likely to have a postoperative myocardial infarction (1.0% vs 0.6%, P = 0.04) and have a 30-day readmission (10.9% vs 8.8%, P < 0.001). Insulin-dependent diabetic patients were more likely to require a 30-day readmission after OAR (24.5% vs 13.5%, P = 0.02) and EVAR (15.1% vs 9.0%, P < 0.001); however, only insulin-dependent diabetes mellitus (IDDM) patients undergoing EVAR experienced higher rates of postoperative myocardial infarction (1.9% vs 0.7%, P < 0.01). After propensity score matching, patients with IDDM undergoing EVAR were additionally at increased risk of mortality at 1-year, 3-year, and 5-year follow-up with the highest risk occurring at the 1-year mark (hazard ratio 1.79, P < 0.0001), while IDDM patients undergoing OAR were only at a significantly increased risk of mortality at 5-year follow-up (hazard ratio 1.90, P = 0.01).

CONCLUSIONS

Patients with insulin-dependent diabetes have greater than 14% one-year mortality following open or endovascular aneurysm repair, compared to 8% for all others. Our findings raise questions about whether insulin-dependent diabetics should have a higher size threshold for prophylactic repair, although further studies are needed to address this question and consider the influence of glycemic control on these outcomes.

Prognostic Value of Nutritional Markers for Long-Term Mortality in Patients Undergoing Endovascular Aortic Repair

Objective: The relationship between nutritional status and morbidity and death in a number of diseases and disorders has garnered considerable attension. In patients having endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAA), we assessed the prognostic value of nutritional markers of albumin (ALB), body mass index (BMI), and geriatric nutritional risk index (GNRI) for long-term mortality. Materials and Methods: Retrospective data analysis was done on patients who had undergone elective EVAR for AAA more than 5 years earlier. Results: A total of 176 patients underwent EVAR for AAA between March 2012 and April 2016. The optimal cutoff value of ALB, BMI, and GNRI for predicting long-term mortality was calculated as 3.75 g/dL (area under the curve [AUC] 0.64), 21.4 kg/m2 (AUC 0.65), and 101.4 (AUC 0.70), respectively. Low ALB, low BMI, and low GNRI as well as age ≥75 years, chronic obstructive pulmonary disease, chronic kidney disease, and active cancer were independent risk factors for long-term mortality. Conclusion: Malnutrition, which is measured by ALB, BMI, and GNRI, is an independent risk factor for long-term mortality in patients receiving EVAR for AAA. Of the nutritional markers, the GNRI can be the most reliable nutritional indicator to identify a potentially high-risk group of mortality after EVAR.

Editor's Choice - Endovascular Aneurysm Repair in High Risk Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

To investigate outcomes of endovascular aneurysm repair (EVAR) in high risk patients.

METHODS

Bibliographic sources (MEDLINE, EMBASE, CINAHL, and CENTRAL) were searched using combinations of thesaurus and free text terms. The review protocol was registered in PROSPERO (CRD42021287207) and reported according to PRISMA 2020. Pooled estimates were calculated using odds ratio (OR) or hazard ratio (HR) and 95% confidence interval (CI) applying the Mantel-Haenszel or inverse variance method. EVAR peri-operative mortality in high risk patients over time was examined with mixed effects meta-regression. The GRADE framework was used to rate the certainty of evidence.

RESULTS

The pooled peri-operative mortality in 18 416 high risk patients who underwent EVAR was 3% (95% CI 2.3 - 4%) and has significantly reduced over time (year of publication p = .003; median study point p = .023). The peri-operative mortality was significantly lower in high risk patients treated with EVAR compared with open repair (OR 0.64; 95% CI 0.45 - 0.92), but no significant difference was found in overall (HR 1.06; 95% CI 0.76 - 1.49) or aneurysm related mortality (HR 0.57; 95% CI 0.21 - 1.55). No significant difference was found in overall mortality between high risk patients treated with EVAR vs. no intervention (HR 0.42; 95% CI 0.14 - 1.26), but the aneurysm related mortality was significantly lower in the former (HR 0.30; 95% CI 0.14 - 0.63). The peri-operative mortality was higher in high risk than normal risk patients treated with EVAR (OR 2.33; 95% CI 1.75 - 3.10), as was the overall mortality (HR 3.50; 95% CI 2.55 - 4.80). The certainty of evidence was very low for EVAR vs. open surgery or no intervention and low for high vs. normal risk patients.

CONCLUSION

The EVAR peri-operative mortality in high risk patients has improved over time. Even though the aneurysm related mortality of EVAR is lower compared with no intervention, EVAR may confer no overall survival benefit.

Migration of High Cardiac Risk Patients from Open to Endovascular Procedures is Evident within the Society for Vascular Surgery Vascular Quality Initiative

BACKGROUND

In this study, pre-operative medical complexity is estimated by the independently validated Vascular Quality Initiative VQI Cardiac Risk Index (CRI). This study aims to identify and correlate trends of CRI for open abdominal aortic aneurysm (OAR) with trends in the CRI for corresponding endovascular aortic repair (EVAR). This assessment of differences in estimated procedural risks will be used to support the theory that, patient migration is an important factor contributing to decreased POMI following open vascular procedures.

METHODS

A retrospective review of VQI data from 2003 to 2020 for all patients undergoing elective aortic repairs (OAR and EVAR) was conducted. The CRI scoring developed for the open repair (oCRI) was applied to both the OAR and EVAR cohorts, with variables specific to EVAR translated from similar open repair factors in the model where feasible. To evaluate for changes across time, patients were grouped into Eras based on year of procedure, subsequently, univariate analysis of post-operative myocardial infarction (POMI) rates and CRI scores were perfomed between each era.

RESULTS

A total of 56,067 elective aortic repairs were identified (83% EVAR, 17% OAR). Within the OAR cohort, the average oCRI estimate was 7.1% with significant decrease across the studied timeframe (8% ± 4.6%→6.9% ± 4.4%, P < 0.001), which corresponded to a significant decrease in observed clinical myocardial infarction (MI) rate (4.1%→1.4%, P < 0.001). Over that same time period, the open CRI was applied to the EVAR cohort, and the average oCRI estimate was 7.2% and showed a significant increase (6.6% ± 2.8%→7.2% ± 4.4%, P < 0.001). Within the EVAR cohort, the eCRI estimate did not show any significant changes over time (average 0.48%), while the actual rate of clinical MI showed a significant decrease (1.1%→0.3%, P = 0.002). Gap analysis was conducted within the EVAR cohort between CRI estimates of procedural risks from an open operation versus an EVAR, which demonstrated that patients within the EVAR cohort would, on an average, has had 6.7% higher risk of POMI had they undergone an open procedure.

CONCLUSIONS

Paradigm shifts with regard to patient selection for aortic repair is evident within this large national cohort. Over time, OAR patients had fewer preoperative estimated cardiac comorbidities and there is a corresponding decrease in POMI rates. As high-risk patients migrate from OAR to EVAR, there has been a subsequent increase in EVAR estimated pre-operative risks as the patients become more medically high-risk. Despite increasing complexity, rates of POMI in EVAR significantly decreased, potentially explained by improved operative technique and peri-operative care.

Outcomes of EVAR Conversion in Octogenarians Treated at a High-Volume Aorta Center

INTRODUCTION

Endovascular aortic aneurysm repair(EVAR) is the dominant treatment strategy for infrarenal abdominal aortic aneurysms(AAA) but is especially preferred among octogenarian(age ≥80-years) patients due to concerns surrounding comorbidity severity and physiological frailty. Correspondingly, EVAR failure resulting in subsequent open conversion(EVAR-c) has been increasingly reported in older patients but there is a paucity of literature focusing on outcomes in this subgroup. The purpose of this analysis was to evaluate our experience with EVAR-c in octogenarians(≥80-years) compared to younger patients(age <80-years).

METHODS

A retrospective review of all non-mycotic EVAR-c procedures(2002-2020) at a single high-volume academic hospital with a dedicated aorta center(https://www.uf-health-aortic-disease-center) was performed. Patients(n=162) were categorized into octogenarian(age ≥80; n=43) and non-octogenarian(age<80; n=119) cohorts and subsequently compared. The primary end-point was 30-day mortality. Secondary end-points included complications, 90-day mortality, and overall survival. Cox regression determined effects of selected covariates on mortality risk. Kaplan-Meier methodology estimated survival.

RESULTS

No difference in pre-admission EVAR re-intervention rates was present(octogenerians-42% vs. non-octogenerians-43%;p=1) although time to first re-intervention was greater in octogenarians(41 vs. non-octogenarians, 15-months;p=.01). Concordantly, time to EVAR-c was significantly longer among octogenarian patients(61 vs. non-octogenarians, 39-months;p<.01). No difference in rupture presentation was evident(14% vs. 10%;p=.6); however, elective EVAR-c occurred less frequently(octogenerians-42% vs. non-octogenerians-59%;p=.07). AAA diameter was significantly larger for elective octogenarian EVAR-c(7.8±1.9cm vs. non-octogenarians, 7.0±1.5cm;p=.02) and type 1a endoleak was the most common indication overall(58%;n=91). Among all presentations, a trend in higher 30-day mortality was evident for octogenarian patients(16% vs. non-octogenarians, 7%;p=.06). Similarly 90-day mortality was greater among octogenarians(26% vs. non-octogenarians, 10%;p=.02). However, incidence of any complication(56% vs. 49%;p=.5), readmission(12% vs. 6%;p=.3), unplanned re-operation(10% vs. 5%;p=.5) and LOS(11 vs. 9 days;p=.3) was not significantly different. Age ≥80 was predictive of short-term mortality after non-elective but not elective cases; however, increasing comorbidity number, non-elective admission and renal/mesenteric revascularization had the strongest association with mortality risk. One- and three-year survival was not different between groups when comparing all patients after the first 90-days postoperatively.

CONCLUSION

Although higher unadjusted peri-operative mortality occurred among octogenarian patients, risk-adjusted elective outcomes were comparable to younger EVAR-c subjects when treated at a high-volume aortic surgery center. This underscores the importance of appropriate patient selection and modulation of operative complexity when feasible to achieve optimal results. Providers caring for octogenarian patients with EVAR failure should consider timely elective referral to high-volume aorta centers to reduce resource utilization and frequency of non-elective presentations.

Hybrid room: Does it offer better accuracy in the proximal deployment of infrarenal aortic endograft?

PURPOSE

This work aims to evaluate the impact of hybrid rooms and their advanced tools on the accuracy of proximal deployment of infrarenal bifurcated endograft (EVAR).

METHODS

A retrospective single centre analysis was conducted between January 2015 and March 2019 including consecutive patients that underwent EVAR. Groups were defined whether the procedure was performed in a hybrid operating room (HOR group) or using a mobile 2D fluoroscopic imaging system (non-HOR group). The accuracy of the proximal deployment was estimated by the distance (mm) between the bottom of the lowest renal artery (LwRA) origin and the endograft radiopaque markers parallax (LwRA/EDG distance) after curvilinear reconstruction. The impact of HOR on the LwRA/EDG distance was investigated using a multiple linear regression model. A composite "proximal neck"-related complications event was studied (Cox models).

RESULTS

Overall, 93 patients (87 %male, median age 73 years) were included with 49 in the HOR group and 44 in the non-HOR group. Preoperative CTA analysis of the proximal neck exhibited similar median length, but different median aortic diameter (p=0.012) and median beta angulation (p=0.027) between groups. The median LwRA/EDG distance was shorter in the HOR group (multivariate model, p=0.022). No difference in "proximal neck"-related complications was evidenced between the HOR and non-HOR groups (univariate analysis, p=0.620). Median follow-up time was respectively 25 [14-28] and 36 months [23-44] in the HOR group and in the non-HOR group (p<0.001).

CONCLUSION

HOR offer more accurate proximal deployment of infrarenal endografts, with however no difference in "proximal neck"-related complications between groups.

Management of Type IA Endoleak After EVAR by Explantation or Custom Made Fenestrated Endovascular Aortic Aneurysm Repair

OBJECTIVE

Proximal type 1 endoleak after endovascular abdominal aortic aneurysmal repair (EVAR) remains challenging to solve with no existing consensus. This work aims to compare two different surgical strategies to remedy type IA endoleak: endograft explantation (EXP) and aortic reconstruction or relining by custom made fenestrated EVAR (F-EVAR).

METHODS

A retrospective single centre analysis between 2009 and 2018 was conducted including patients treated for type IA endoleak after EVAR with either EXP or F-EVAR. The choice of surgical technique was based on morphological factors (F-EVAR eligibility), sac growth rate, emergency presentation and/or patient symptoms. Technical success, morbidity, secondary interventions, 30 day mortality, and long term survival according to Kaplan-Meier were determined for each group and compared.

RESULTS

Fifty-nine patients (91% male, mean age 79 years) underwent either EXP (n = 26) or F-EVAR (n = 33) during the study period. The two groups were equivalent in terms of comorbidity and age at the time of procedure. The median time from initial EVAR was 60.4 months (34-85 months), with no difference between groups. The maximum aneurysm diameter was greater in the EXP group compared with the F-EVAR group, 86 mm (65-100) and 70 mm (60-80), respectively (p = .008). Thirty day secondary intervention (EXP: 11.5% vs. F-EVAR: 9.1%) and mortality (EXP: 3.8% vs. F-EVAR: 3.3%) rates did not differ between groups, while major adverse events at 30 days, defined by the current SVS guidelines, were lower in the F-EVAR group (2.4% vs. 13.6%; p = .016). One year survival rates were similar between the groups (EXP: 84.0% vs. F-EVAR: 86.6%).

CONCLUSION

Open explantation and endovascular management with a fenestrated device for type IA endoleak after EVAR can be achieved in high volume centres with satisfactory results. F-EVAR is associated with decreased early morbidity. Open explantation is a relevant option because of acceptable outcomes and the limited applicability of F-EVAR.

Contemporary outcomes of endovascular abdominal aortic aneurysm repair in patients deemed unfit for open surgical repair

OBJECTIVE

Endovascular abdominal aortic aneurysm repair (EVAR) has been preferred to open surgical repair (OSR) for the treatment of abdominal aortic aneurysms (AAAs) in high-risk patients. We compared the perioperative and long-term outcomes of EVAR for patients designated as unfit for OSR using a large national dataset.

METHODS

The Vascular Quality Initiative database was queried for patients who had undergone elective EVAR for AAAs >5 cm from 2013 to 2019. The patients were stratified into two cohorts according to their suitability for OSR (fit vs unfit). The primary outcomes included perioperative (in-hospital) major adverse events, perioperative mortality, and mortality at 1 and 5 years. Patient demographics and postoperative outcomes were analyzed to identify the predictors of perioperative and long-term mortality.

RESULTS

Of 16,183 EVARs, 1782 patients had been deemed unfit for OSR. The unfit cohort was more likely to be older and female, with a greater proportion of hypertension, coronary artery disease, congestive heart failure, chronic obstructive pulmonary disease, and larger aneurysm diameters. Postoperatively, the unfit cohort was more likely to have experienced cardiopulmonary complications (6.5% vs 3%; P < .001), with greater perioperative mortality (1.7% vs 0.6%; P < .001) and 1- and 5-year mortality (13% and 29% for the unfit vs 5% and 14% for the fit cohorts, respectively; P < .001). A subgroup analysis of the unfit cohort revealed that those deemed unfit because of a hostile abdomen had significantly lower 1- and 5-year mortality (6% and 20%, respectively) compared with those considered unfit because of cardiopulmonary compromise and frailty (14% and 30%, respectively; P = .451). Reintervention-free survival at 1 and 5 years was significantly greater in the fit cohort (93% and 82%, respectively) compared with that for the unfit cohort (85% and 68%, respectively; P < .001). The designation as unfit for OSR was an independent predictor of both perioperative (odds ratio, 1.59; 95% confidence interval [CI], 1.03-2.46; P = .038) and long-term mortality (hazard ratio [HR], 1.92; 95% CI, 1.69-2.17; P < .001). Advanced age (odds ratio, 2.91; 95% CI, 1.28-6.66; P = .011) was the strongest determinant of perioperative mortality, and end-stage renal disease (HR, 2.51; 95% CI, 1.78-3.55; P < .001) was the strongest predictor of long-term mortality. Statin use (HR, 0.77; 95% CI, 0.69-0.87; P < .001) and angiotensin-converting enzyme inhibitor use (HR, 0.83; 95% CI, 0.75-0.93; P < .001) were protective of long-term mortality.

CONCLUSIONS

Despite low perioperative mortality, the long-term mortality of those designated by operating surgeons as unfit for OSR was rather high for patients undergoing elective EVAR, likely owing to the competing risk of death from medical frailty. An unfit designation because of a hostile abdomen did not confer any additional risks after EVAR. Judicious estimation of the patient's life expectancy is essential when considering the treatment options for this subset of patients deemed unfit for OSR.

Adverse cardiac events after vascular surgery are prevalent despite negative results of preoperative stress testing

OBJECTIVE

Cardiac risk assessment is a critical component of vascular disease management before surgical intervention. The predictive risk reduction of a negative cardiac stress test result remains poorly defined. The objective of this study was to compare the incidence of postoperative cardiac events among patients with negative stress test results vs those who did not undergo testing.

METHODS

We reviewed all patients who underwent elective open abdominal aortic aneurysm repair, suprainguinal bypass, endovascular aneurysm repair (EVAR), carotid endarterectomy (CEA), and infrainguinal bypass within the Vascular Study Group of New England from 2003 to 2017. We excluded patients with positive stress test results (n = 3312) and studied two mutually exclusive groups: elective surgery patients with a negative stress test result and elective surgery patients with no stress test (total n = 26,910). The primary outcome was a composite of in-hospital postoperative cardiac events (dysrhythmia, heart attack, heart failure) or death.

RESULTS

A preoperative stress test was obtained in 66.3% of open repairs, 42.8% of suprainguinal bypasses, 37.1% of EVARs, 36.0% of CEAs, and 31.2% of infrainguinal bypasses. The proportion of patients receiving a preoperative stress test varied widely across centers, from 37.1% to 80.0%. The crude odds ratio of in-hospital postoperative cardiac event or death was 1.37 (95% confidence interval [CI], 1.07-1.76) for open repair and 1.52 (CI, 1.13-2.03) for suprainguinal bypass, indicating that patients with negative stress test results before these procedures were 37% and 52% more likely to suffer a postoperative event or die compared with patients selected to proceed directly to surgery without testing. Conversely, the crude odds ratio was 0.92 (CI, 0.66-1.29) for EVAR, 0.92 (CI, 0.70-1.21) for CEA, and 1.13 (CI, 0.90-1.40) for infrainguinal bypass, indicating that patients undergoing these procedures had a similar likelihood of sustaining an event whether they had a negative stress test result or proceeded directly to surgery without a stress test.

CONCLUSIONS

The use of cardiac stress testing before vascular surgery varies widely throughout New England. Whereas patients are often appropriately selected to proceed directly to surgery, a negative preoperative stress test result should not assuage the concern for an adverse outcome as these patients retain a substantial likelihood of cardiac events, especially after large-magnitude procedures.

Comparing Long-term Mortality After Carotid Endarterectomy vs Carotid Stenting Using a Novel Instrumental Variable Method for Risk Adjustment in Observational Time-to-Event Data

IMPORTANCE

Choosing between competing treatment options is difficult for patients and clinicians when results from randomized and observational studies are discordant. Observational real-world studies yield more generalizable evidence for decision making than randomized clinical trials, but unmeasured confounding, especially in time-to-event analyses, can limit validity.

OBJECTIVES

To compare long-term survival after carotid endarterectomy (CEA) and carotid artery stenting (CAS) in real-world practice using a novel instrumental variable method designed for time-to-event outcomes, and to compare the results with traditional risk-adjustment models used in observational research for survival analyses.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter cohort study was performed. The Vascular Quality Initiative, an observational quality improvement registry, was used to compare long-term mortality after CEA vs CAS. The study included 86 017 patients who underwent CEA (n = 73 312) or CAS (n = 12 705) between January 1, 2003, and December 31, 2016. Patients were followed up for long-term mortality assessment by linking the registry data to Medicare claims. Medicare claims data were available through September 31, 2015.

EXPOSURE

Procedure type (CEA vs CAS).

MAIN OUTCOMES AND MEASURES

The hazard ratios (HRs) of all-cause mortality using unadjusted, adjusted, propensity-matched, and instrumental variable methods were examined. The instrumental variable was the proportion of CEA among the total carotid procedures (endarterectomy and stenting) performed at each hospital in the 12 months before each patient's index operation and therefore varies over the study period.

RESULTS

Participants who underwent CEA had a mean (SD) age of 70.3 (9.4) years compared with 69.1 (10.4) years for CAS, and most were men (44 191 [60.4%] for CEA and 8117 [63.9%] for CAS). The observed 5-year mortality was 12.8% (95% CI, 12.5%-13.2%) for CEA and 17.0% (95% CI, 16.0%-18.1%) for CAS. The unadjusted HR of mortality for CEA vs CAS was 0.67 (95% CI, 0.64-0.71), and Cox-adjusted and propensity-matched HRs were similar (0.69; 95% CI, 0.65-0.74 and 0.71; 95% CI, 0.65-0.77, respectively). These findings are comparable with published observational studies of CEA vs CAS. However, the association between CEA and mortality was more modest when estimated by instrumental variable analysis (HR, 0.83; 95% CI, 0.70-0.98), a finding similar to data reported in randomized clinical trials.

CONCLUSIONS AND RELEVANCE

The study found a survival advantage associated with CEA over CAS in unadjusted and Cox-adjusted analyses. However, this finding was more modest when using an instrumental variable method designed for time-to-event outcomes for risk adjustment. The instrumental variable-based results were more similar to findings from randomized clinical trials, suggesting this method may provide less biased estimates of time-dependent outcomes in observational analyses.

A comparative analysis of long-term mortality after carotid endarterectomy and carotid stenting

BACKGROUND

The value of carotid intervention is predicated on long-term survival for patients to derive a stroke prevention benefit. Randomized trials report no significant difference in survival after carotid endarterectomy (CEA) vs carotid artery stenting (CAS), whereas observational studies of "real-world" outcomes note that CEA is associated with a survival advantage. Our objective was to examine long-term mortality after CEA vs CAS using a propensity-matched cohort.

METHODS

We studied all patients who underwent CEA or CAS within the Vascular Quality Initiative from 2003 to 2013 (CEA, n = 29,235; CAS, n = 4415). Long-term mortality information was obtained by linking patients in the registry to their respective Medicare claims file. We assessed the long-term rate of mortality for CEA and CAS using Kaplan-Meier estimation. We assessed the crude, adjusted, and propensity-matched (total matched pairs, n = 4261) hazard ratio (HR) of mortality for CEA vs CAS using Cox regression.

RESULTS

The unadjusted Kaplan-Meier estimated 5-year mortality was 14.0% for CEA and 18.3% for CAS. The crude HR of all-cause mortality for CEA vs CAS was 0.75 (95% confidence interval [CI], 0.70-0.81), indicating that patients who underwent CEA were 25% less likely to die before those who underwent CAS. This survival advantage persisted after adjustment for age, sex, and comorbidities (adjusted HR, 0.75; 95% CI, 0.69-0.82). This effect was confirmed on a propensity-matched analysis, with an HR of 0.76 (95% CI, 0.69-0.85). Finally, these findings were robust to subanalyses that stratified patients by presenting symptoms and were more pronounced in symptomatic patients (adjusted HR, 0.69; 95% CI, 0.61-0.79) than in asymptomatic patients (adjusted HR, 0.80; 95% CI, 0.71-0.90).

CONCLUSIONS

During the last 15 years, patients who underwent CEA in the Vascular Quality Initiative have a long-term survival advantage over those who underwent CAS in real-world practice. Despite no difference in long-term survival in randomized trials, our observational study demonstrated a survival benefit for CEA that did not diminish with risk adjustment.

Low mortality rates after endovascular aortic repair expand use to high-risk patients

OBJECTIVE

The 2010 endovascular aneurysm repair (EVAR) trial 2 (EVAR 2) reported that patients with comorbidity profiles rendering them unfit for open aneurysm repair who underwent EVAR did not experience a survival advantage compared with those who did not undergo intervention. These patients experienced a 30-day mortality of 7.3%, whereas reports from similar cohorts reported far lower mortality rates. The primary objective of our study was to compare the incidence of 30-day mortality in low- and high-risk patients undergoing EVAR in a contemporary data set, using patient risk stratification criteria from EVAR 2. Secondarily, we sought to identify risk factors associated with a disproportionate contribution to 30-day mortality risk.

METHODS

Data were obtained from the 2005 to 2013 American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) Participant Use Data Files (N = 24,813). Patients were included in the high-risk cohort with the presence of renal, respiratory, or cardiac preoperative criteria alone or in combination. Renal impairment criteria were defined as dialysis and creatinine concentration >2.26 mg/dL. Respiratory impairment criteria included history of chronic obstructive pulmonary disease and preoperative ventilator support. Cardiac impairment criteria included history of myocardial infarction, congestive heart failure, angina, and prior coronary intervention. Patient and procedural characteristics and 30-day postoperative outcomes were compared using Pearson χ2 tests for categorical variables and Wilcoxon rank sum tests for continuous variables.

RESULTS

Among 24,813 patients undergoing EVAR, 12,043 (48%) patients were characterized as high risk (at least one impairment criterion); 12,770 (52%) patients were stratified as low risk. The 30-day mortality rate was 1.9% in the high-risk cohort compared with the 7.3% reported by EVAR 2, and it was higher in the high-risk cohort compared with the low-risk cohort (1.9% vs 0.9%; P < .001). Whereas the presence of each comorbidity increased the odds of 30-day mortality (respiratory odds ratio [OR], 1.62; 95% confidence interval [CI], 1.16-2.26; P = .005; cardiac OR, 1.55; 95% CI, 1.14-2.10; P = .005), the presence of renal criteria disproportionately increased the odds of mortality threefold (OR, 3.42; 95% CI, 2.31-5.09; P < .001).

CONCLUSIONS

Contemporary 30-day mortality after EVAR in high-risk patients is substantially lower than that reported in the EVAR 2 trial. Whereas low- and high-risk stratification by current comorbidity criteria is appropriate, attention needs to be paid to disproportionate risk contribution from renal disease to mortality compared with cardiac and pulmonary comorbidities. Given the lower mortality risk than previously described, patients stratified as high risk should be thoughtfully considered for definitive EVAR.

A pilot study for long-term outcome assessment after aortic aneurysm repair using Vascular Quality Initiative data matched to Medicare claims

OBJECTIVE

Accurate and complete long-term postoperative outcome data are critical to improving value in health care delivery. The Society for Vascular Surgery Vascular Quality Initiative (VQI) is an important tool to achieve this goal in vascular surgery. To improve on the capture of long-term outcomes after vascular surgery procedures for patients in the VQI, we sought to match VQI data to Medicare claims for comprehensive capture of major clinical outcomes in the first several years after vascular procedures.

METHODS

Patient and procedure characteristics for abdominal aortic aneurysm procedures captured in the Society for Vascular Surgery VQI between January 1, 2002, and December 31, 2013, were matched to Medicare claims data using an indirect identifier methodology. Late outcomes captured in the VQI and in Medicare claims were compared.

RESULTS

Matching procedures yielded 9895 endovascular aneurysm repair (EVAR) patients (82.4% of eligible VQI patients) and 3405 open aneurysm repair (OAR) patients (74.4% of eligible). Comparison of patients who did and did not match to a Medicare claim demonstrated similar patient and procedure characteristics. Evaluation of late outcomes revealed good patient-level agreement on mortality for both EVAR (κ, 0.64) and OAR (κ, 0.82). Postoperative reintervention rates demonstrated lower agreement for both EVAR (κ, 0.26) and OAR (κ, 0.16).

CONCLUSIONS

This work demonstrates the feasibility of an algorithm using indirect identifiers to match VQI patients and procedures to Medicare claims data. The refinement of this strategy will focus on establishing and improving algorithms related to identifying and categorizing late events after EVAR and may serve as a mechanism to ensure that the best quality follow-up information is achieved within the VQI.

Survival After Endovascular Abdominal Aortic Aneurysm Repair in a Population with a Low Incidence of Coronary Artery Disease

BACKGROUND

Endovascular aortic aneurysm repair (EVAR) is a prophylactic procedure, so the decision to operate should consider, as recent guidelines suggest, the life expectancy of the patient. Several models for predicting life span have been already designed, but little is known about how intervened patients evolve in Southern European Countries, where the incidence of coronary artery disease, the main cause of death among these subjects, is low.

METHODS

We conducted a retrospective analysis of 176 consecutive patients who underwent elective EVAR at the Vascular Surgery Department of the Hospital del Mar (Barcelona, Spain) during 2000-2014. Cox regressions were performed to identify preoperative factors associated with long-term survival after EVAR, and a risk model was developed.

RESULTS

Three- and five-year survival rates were 73.9 and 53.9 %, respectively. During the follow-up, 72 deaths (40.9 %) were registered, cancer being the most frequent cause (41.7 %). Preoperative variables negatively associated with long-term survival were serum creatinine ≥ 150 µmol/L (HR 2.5; 95 % CI 1.4-4.2), chronic obstructive pulmonary disease (HR 1.9; 95 % CI 1.2-3.1), atrial fibrillation (HR 2.0; 95 % CI 1.2-3.4), and prior cancer history (HR 1.9; 95 % CI 1.2-3.1). Distal pulses present in both lower limbs were marginally associated with survival (HR 0.65; 95 % CI 0.4-1.07). The survival predictive model showed a good discrimination capacity (C statistic = 0.703; 95 % CI 0.641-0.765).

CONCLUSIONS

Long-term survival of patients submitted to EVAR in our setting was worse than expected and markedly related to cancer. Our study suggests that predictive models for long-term survival after EVAR may be influenced by regional characteristics of the intervened population. This effect should be taken in consideration in the decision-making process of these patients.

Long-term outcomes and factors influencing late survival following elective abdominal aortic aneurysm repair: A 24-year experience

Background

Abdominal aortic aneurysms can be either treated by an open abdominal aortic aneurysm repair or an endovascular repair. Comparing clinical predictors of outcomes and those which influence survival rates in the long term is important in determining the choice of treatment offered and the decision-making process with patients.

Aims

To determine the influence of pre-existing clinical predictors and perioperative determinants on late survival of elective open abdominal aortic aneurysm repair and endovascular repair at a tertiary hospital.

Methods

Consecutive patients undergoing elective abdominal aortic aneurysm repair from 1990 to 2013 were included. Data were collected from a prospectively acquired database and death data were gathered from the Queensland state death registry. Pre-existing risks and perioperative factors were assessed independently. Kaplan–Meier and Cox regression modeling were performed.

Results

During the study period, 1340 abdominal aortic aneurysms were repaired electively, of which 982 were open abdominal aortic aneurysm repair. The average age was 72.4 years old and 81.7% were males. The cumulative percentage survival rates for open abdominal aortic aneurysms repair at 5, 10, 15 and 20 years were 79, 49, 31 and 22, respectively. The corresponding 5-, 10- and 15-year survival rates for endovascular repair were not significantly different at 75, 49 and 33%, respectively (P = 0.75). Predictors of reduced survival were advanced age, American Society of Anaesthesiology scores, chronic obstructive pulmonary disease, renal impairment, bifurcated grafts, peripheral vascular disease and congestive heart failure.

Conclusions

Open repair offers a good long-term treatment option for patients with an abdominal aortic aneurysm and in our experience there is no significant difference in late survival between open abdominal aortic aneurysms repair and endovascular repair. Consideration of the factors identified in this study that predict reduced long-term survival for open abdominal aortic aneurysms repair and endovascular repair should be considered when deciding repair of abdominal aortic aneurysm.

[Aneurysms of the abdominal aorta and iliac arteries: paradigm shift - operative therapy, if possible endovascular?]

BACKGROUND

Therapy of abdominal aortic aneurysms (AAA) is currently based on a high level of evidence. This is not true in the same manner for iliac artery aneurysms (IAA) which are frequently associated with AAAs and occur only rarely as isolated lesions. The therapeutic principles apply in the same way to both aneurysm locations.

OBJECTIVES

New findings, improved perioperative care and the rapid development of minimally invasive techniques require a constant update which is the aim of this article concerning the therapy of AAAs and IAAs.

MATERIAL AND METHODS

A systematic literature review was performed in PubMed and Medline and priority was given to recent publications with a high level of evidence.

RESULTS

Endovascular aneurysm repair (EVAR) and open aneurysm repair (OAR) result in a similar long-term survival. The perioperative survival advantage with EVAR persists only during medium-term postoperative courses. The reintervention rate after EVAR is substantially higher compared to OAR. For older patients and those who are considered unfit for OAR the expected benefits from EVAR has not been proven to date. Aneurysmal ruptures after EVAR demonstrate that a life-long surveillance of these patients is necessary.

CONCLUSION

Therapy of AAAs and IAAs is increasingly being performed by EVAR. Even the majority of complex aneurysms are amenable to minimally invasive treatment. Nevertheless, indications for OAR continue to exist. Screening for AAAs results in a decrease of aneurysmal ruptures for which EVAR is also gaining importance.