Comparison of Endovascular Stent Grafts for Abdominal Aortic Aneurysm Repair in Medicare Beneficiaries

The effect of preoperative smoking status on carotid endarterectomy outcomes in asymptomatic patients

OBJECTIVE

The current medical landscape lacks comprehensive data regarding the impact of preoperative smoking status on both short and long-term outcomes for patients undergoing carotid endarterectomy (CEA). This study seeks to elucidate the influence of smoking cessation on in-hospital and long-term outcomes in this patient population.

METHODS

Data were collected from the Vascular Quality Initiative for all asymptomatic patients who underwent CEA from 2016 to 2023. Outcomes were compared across three different smoking status groups: never smoke (NS), current smoker (CS), and quit >30 days ago. Our primary outcomes included in-hospital stroke, death, and myocardial infarction. Secondary outcomes included 1-year and 3-year death. We used inverse probability of treatment weighting to balance the following preoperative factors: age, gender, race, ethnicity, body mass index, diabetes, coronary artery disease, prior congestive heart failure, renal dysfunction, chronic obstructive pulmonary disease, hypertension, prior coronary artery bypass grafting/percutaneous coronary intervention, prior CEA/carotid artery stenting, degree of stenosis, urgency, anesthesia type, and medications.

RESULTS

The final analysis included 85,237 CEA cases with 22,343 NS (26.2%), 41,731 who quit >30 days ago (49.0%) , and 21,163 CS (24.8%). Notably, NS tended to be older and more likely to be female. In contrast, patients who quit >30 days ago were more likely to have comorbidities, including obesity, coronary artery disease, prior congestive heart failure, and CKD, as well as prior procedures. Patients who are CS were more likely to have chronic obstructive pulmonary disease and stenosis of >80%. After inverse probability of treatment weighting, we found no statistical difference for in-hospital stroke, death, myocardial infarction outcomes across the three groups. However, the long-term outcomes revealed quit >30 days ago and CS compared with NS had higher odds of 1-year death (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.2-1.5; P < .001; OR, 1.4; 95% CI, 1.2-1.6; P < .001) and 3-year death (OR, 1.5; 95% CI, 1.3-1.6; P < .001; OR, 1.5; 95% CI, 1.4-1.7; P < .001), respectively. There was no significant difference in midterm mortality outcomes between those who quit >30 days ago and CS.

CONCLUSIONS

In this large national study, we found that smoking status did not emerge as a substantial determinant of adverse short-term outcomes for asymptomatic patients undergoing CEA. However, smoking did adversely affect midterm mortality in these patients. In light of these findings, our study suggests that delaying CEA for smokers may not be warranted. It is crucial to recognize that the complex relationship between smoking and surgical outcomes requires further exploration and validation through additional prospective studies.

Endovascular abdominal aortic aneurysm repair (EVAR) outcomes of unibody and single/double docking limb endografts in Medicare beneficiaries between 2012 and 2018

OBJECTIVE

The evaluation of perioperative and long term outcomes for endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAA) using anatomic (unibody) and proximal neck fixated (docking limbs) endografts across consecutive time cohorts.

DESIGN

This study compares the outcomes of EVAR in Medicare patients stratified by mode of fixation.

METHODS

All patients who underwent EVAR between 2012 and 2018 were identified in the Medicare database. Anatomic fixation (AF) and proximal fixation (PF) grafts were differentiated using Current Procedural Terminology (CPT) codes. The AF population was divided into three-time cohorts based on iterative changes in graft design: Cohort 1: (01/01/2012-20/07/2014); Cohort 2: (21/07/2014-09/05/2016); and Cohort 3: (10/05/2016-31/12/2017). The PF cohort was similarly divided into these three periods. Outcomes were evaluated through 31/12/2020 and included all-cause mortality, aortic rupture, and aortic-related reintervention.

RESULTS

32,031 patients underwent EVAR during the study period; 4729 were AF and 27,302 were PF. There were more women (p < .001) and patients with peripheral vascular disease (PVD) (p < .001) in the AF group. There were no group differences in perioperative outcomes. In Cohort 1, there was a higher rate of reintervention (11.9% vs 7.6%; p < .001) and aortic rupture (5.3% vs 4.0%; p = .019) in the AF group compared to the PF group. In Cohort 2, reintervention, aortic rupture, and reintervention rates were similar between the two groups (p = NS). In Cohort 3, the reintervention and aortic rupture rates were similar between the two groups (p = NS).

CONCLUSION

The higher rates of aortic rupture and reintervention seen in the AF group in Cohort 1 when compared with the PF group did not persist in Cohorts 2 and 3. This suggests that improvements in graft design may have led to durability which is similar to that of PF grafts. However, late aneurysm related complications are inherent risks after EVAR and long-term surveillance remains necessary.

Seven years of the transcarotid artery revascularization surveillance project, comparison to transfemoral stenting and endarterectomy

OBJECTIVE

This study utilizes the latest data from the Vascular Quality Initiative (VQI), which now encompasses over 50,000 transcarotid artery revascularization (TCAR) procedures, to offer a sizeable dataset for comparing the effectiveness and safety of TCAR, transfemoral carotid artery stenting (tfCAS), and carotid endarterectomy (CEA). Given this substantial dataset, we are now able to compare outcomes overall and stratified by symptom status across revascularization techniques.

METHODS

Utilizing VQI data from September 2016 to August 2023, we conducted a risk-adjusted analysis by applying inverse probability of treatment weighting to compare in-hospital outcomes between TCAR vs tfCAS, CEA vs tfCAS, and TCAR vs CEA. Our primary outcome measure was in-hospital stroke/death. Secondary outcomes included myocardial infarction and cranial nerve injury.

RESULTS

A total of 50,068 patients underwent TCAR, 25,361 patients underwent tfCAS, and 122,737 patients underwent CEA. TCAR patients were older, more likely to have coronary artery disease, chronic kidney disease, and undergo coronary artery bypass grafting/percutaneous coronary intervention as well as prior contralateral CEA/CAS compared with both CEA and tfCAS. TfCAS had higher odds of stroke/death when compared with TCAR (2.9% vs 1.6%; adjusted odds ratio [aOR], 1.84; 95% confidence interval [CI], 1.65-2.06; P < .001) and CEA (2.9% vs 1.3%; aOR, 2.21; 95% CI, 2.01-2.43; P < .001). CEA had slightly lower odds of stroke/death compared with TCAR (1.3% vs 1.6%; aOR, 0.83; 95% CI, 0.76-0.91; P < .001). TfCAS had lower odds of cranial nerve injury compared with TCAR (0.0% vs 0.3%; aOR, 0.00; 95% CI, 0.00-0.00; P < .001) and CEA (0.0% vs 2.3%; aOR, 0.00; 95% CI, 0.0-0.0; P < .001) as well as lower odds of myocardial infarction compared with CEA (0.4% vs 0.6%; aOR, 0.67; 95% CI, 0.54-0.84; P < .001). CEA compared with TCAR had higher odds of myocardial infarction (0.6% vs 0.5%; aOR, 1.31; 95% CI, 1.13-1.54; P < .001) and cranial nerve injury (2.3% vs 0.3%; aOR, 9.42; 95% CI, 7.78-11.4; P < .001).

CONCLUSIONS

Although tfCAS may be beneficial for select patients, the lower stroke/death rates associated with CEA and TCAR are preferred. When deciding between CEA and TCAR, it is important to weigh additional procedural factors and outcomes such as myocardial infarction and cranial nerve injury, particularly when stroke/death rates are similar. Additionally, evaluating subgroups that may benefit from one procedure over another is essential for informed decision-making and enhanced patient care in the treatment of carotid stenosis.

A Contemporary Evaluation of the Centers for Medicare and Medicaid Services High-risk Indicators for Carotid Endarterectomy

OBJECTIVE

Compare stroke/death outcomes across carotid endarterectomy (CEA), transcarotid artery revascularization (TCAR), and transfemoral carotid artery stenting (TFCAS) using Centers for Medicare and Medicaid Services (CMS) high-risk criterion.

BACKGROUND

Existing literature has revealed inconsistencies with CMS risk guidelines. With recent approval for TCAR and TFCAS in standard-risk patients, an updated analysis of guidelines is needed.

METHODS

Data from the Vascular Quality Initiative (VQI) (2016-2023) on CEA, TFCAS, or TCAR patients were used. We used inverse probability of treatment weighting to compare in-hospital stroke/death rates across procedures for high-risk criteria: contralateral occlusion (CLO), prior CEA, CAS, radiation, neck surgery, moderate to severe CHF, severe COPD (on home O 2 ), unstable angina, recent MI (<6 mo), and age (≥75 years-old).

RESULTS

A total of 199,050 patients were analyzed, of whom 122,737 (62%) patients underwent CEA, 50,095 (25%) TCAR, and 26,218 (13%) TFCAS. TCAR had lower odds of stroke/death compared with CEA in patients with CLO [aOR=0.73 (95% CI: 0.55-0.98], P =0.035] and radiation [aOR=0.44 (95% CI: 0.23-0.82), P =0.010]. Contrary to CMS criteria, CEA patients did not have higher stroke/death in patients with prior CEA, CAS, neck surgery, moderate to severe CHF, severe COPD, unstable angina, recent MI, or age (≥75) compared with TCAR and TFCAS.

CONCLUSIONS

While CMS high-risk criteria have traditionally been recognized as contraindications for CEA, our study reveals inconsistencies-with CEA performing similarly to TCAR and significantly better than TFCAS in patients with prior CEA, moderate to severe CHF, recent MI, or age (≥75). As a result, the definition of high-risk criteria may warrant reconsideration.

Comparison of Unibody and Non-Unibody Endografts for Abdominal Aortic Aneurysm Repair in Medicare Beneficiaries: The SAFE-AAA Study

BACKGROUND

Concerns have been raised about the long-term performance of aortic stent grafts for the treatment of abdominal aortic aneurysms, in particular, unibody stent grafts (eg, Endologix AFX AAA stent grafts). Only limited data sets are available to evaluate the long-term risks related to these devices. The SAFE-AAA Study (Comparison of Unibody and Non-Unibody Endografts for Abdominal Aortic Aneurysm Repair in Medicare Beneficiaries Study) was designed with the Food and Drug Administration to provide a longitudinal assessment of the safety of unibody aortic stent grafts among Medicare beneficiaries.

METHODS

The SAFE-AAA Study was a prespecified, retrospective cohort study evaluating whether unibody aortic stent grafts are noninferior to non-unibody aortic stent grafts with respect to the composite primary outcome of aortic reintervention, rupture, and mortality. Procedures were evaluated from August 1, 2011, through December 31, 2017. The primary end point was evaluated through December 31, 2019. Inverse probability weighting was used to account for imbalances in observed characteristics. Sensitivity analyses were used to evaluate the effect of unmeasured confounding, including assessment of the falsification end points heart failure, stroke, and pneumonia. A prespecified subgroup included patients treated from February 22, 2016, through December 31, 2017, corresponding to the market release of the most contemporary unibody aortic stent grafts (Endologix AFX2 AAA stent graft).

RESULTS

Of 87 163 patients who underwent aortic stent grafting at 2146 US hospitals, 11 903 (13.7%) received a unibody device. The average age of the total cohort was 77.0±6.7 years, 21.1% were female, 93.5% were White, 90.8% had hypertension, and 35.8% used tobacco. The primary end point occurred in 73.4% of unibody device-treated patients versus 65.0% of non-unibody device-treated patients (hazard ratio, 1.19 [95% CI, 1.15-1.22]; noninferior P value of 1.00; median follow-up, 3.4 years). Falsification end points were negligibly different between groups. In the subgroup treated with contemporary unibody aortic stent grafts, the cumulative incidence of the primary end point occurred in 37.5% of unibody device-treated patients and 32.7% of non-unibody device-treated patients (hazard ratio, 1.06 [95% CI, 0.98-1.14]).

CONCLUSIONS

In the SAFE-AAA Study, unibody aortic stent grafts failed to meet noninferiority compared with non-unibody aortic stent grafts with respect to aortic reintervention, rupture, and mortality. These data support the urgency of instituting a prospective longitudinal surveillance program for monitoring safety events related to aortic stent grafts.

A Comparison of Suprarenal and Infrarenal Fixation and Renal Volumetric Analysis after Endovascular Aneurysm Repair

OBJECTIVE

Clinical and experimental studies of the stent-graft fixation impact on renal volume after endovascular abdominal aortic aneurysm repair have focused on glomerular filtration rate (GFR) and the results were controversial. The aim of this study was to analyze and compare the impact of the supra (SRF group) and infra (IRF group) renal stent-graft fixation on the renal volume.

METHODS

Between December 2016 and December 2019, all patients treated with EVAR were retrospectively analyzed. Patients with atrophic or multicystic kidney, renal transplantation, ultrasound or incomplete follow-up were excluded. Renal volume in both groups was extracted with a semi-automatic segmentation from contrast-enhanced CT-scan performed before the procedure, at 1 month and at 12 months follow-up. A subgroup analyze of the SRF group was performed in order to study impact of the stent struts position relative to the renal arteries.

RESULTS

63 patients were analyzed (SRF: 32, IRF: 31). Demographic and anatomical characteristics were similar between the groups. Procedure contrast volume was higher in the IRF group (P= 0.01). At 12-months, the renal volume decreased of 1.4 % in the SRF group and 2.3 % in the IRF group (P=0.86). The SRF sub group analysis showed only 2 patients with no stent struts crossing renal arteries. In the remaining cases, struts crossed one renal artery in 60% of cases (19 patients) and 2 renal arteries in 34% of cases (11 patients). The renal volume decrease was not correlated to the presence of stent wires struts, crossing renal artery.

CONCLUSIONS

Stent-graft with supra renal fixation seems not to be correlated with renal volume deterioration. A randomized clinical trial with a higher effective and longer follow-up is needed to assess the impact of SRF on the renal function.

Editor's Choice - Comparison of Outcomes for Major Contemporary Endograft Devices Used for Endovascular Repair of Intact Abdominal Aortic Aneurysms

OBJECTIVE

To compare rates of mortality, rupture, and secondary intervention following endovascular repair (EVAR) of intact abdominal aortic aneurysms (AAA) using contemporary endograft devices from three major manufacturers.

METHODS

This was a retrospective cohort study using linked clinical registry (Australasian Vascular Audit) and all payer administrative data. Patients undergoing EVAR for intact AAA between 2010 and 2019 in New South Wales, Australia were identified. Rates of all cause death, secondary rupture, and secondary intervention (subsequent aneurysm repair; other secondary aortic intervention) were compared for patients treated with Cook, Medtronic, and Gore standard devices. Inverse probability of treatment weighted proportional hazards and competing risk regression were used to adjust for patient, clinical, and aneurysm characteristics, using Cook as the referent device.

RESULTS

This study identified 2 874 eligible EVAR patients, with a median follow up of 4.1 (maximum 9.5) years. Mortality rates were similar for patients receiving different devices (ranging between 7.0 and 7.3 per 100 person years). There was no statistically significant difference between devices in secondary rupture rates, which ranged between 0.4 and 0.5 per 100 person years. Patients receiving Medtronic and Gore devices tended to have higher crude rates of subsequent aneurysm repair (1.5 per 100 person years) than patients receiving Cook devices (0.8 per 100 person years). This finding remained in the adjusted analysis, but was only statistically significant for Medtronic devices (HR 1.57, 95% CI 1.02 - 2.47; HR 1.73, 95% CI 0.94 - 3.18, respectively).

CONCLUSION

Major endograft devices have similar overall long term safety profiles. However, there may be differences in rates of secondary intervention for some devices. This may reflect endograft durability, or patient selection for different devices based on aneurysm anatomy. Continuous comparative assessments are needed to guide evidence for treatment decisions across the range of available devices.

Midterm outcomes of 455 patients receiving the AFX2 endovascular graft for the treatment of abdominal aortic aneurysm: A retrospective multi-center analysis

Since being introduced into clinical practice the AFX family of endografts has undergone labelling updates, design and manufacturing changes to address a Type III failure mode. The published literature on the performance of the current endograft-AFX2 -is limited to small series with limited follow up. The present study reports the largest series of patients implanted with AFX2 for the treatment of abdominal aortic aneurysms. The study was a retrospective, 5 center study of patients receiving an AFX2 endograft from January 2016 until Dec 2020. Electronic case report forms were provided to four of the centers, with one additional site providing relevant outcomes in an independent dataset. Relevant outcomes were reported via Kaplan-Meier analysis and included all-cause mortality, aneurysm-related mortality, post EVAR aortic rupture, open conversion, device related reinterventions and endoleaks. Among a cohort of 460 patients, 405 underwent elective repair of an AAA, 50 were treated for a ruptured AAA, and 5 were aorto-iliac occlusive disease cases. For the elective cohort (mean age 73.7y, 77% male, mean AAA diameter 5.4cm), the peri-operative mortality was 1.7%. Freedom from aneurysm-related mortality was 98.2% at 1,2,3 and 4 years post-operatively, there were no post-operative aortic ruptures, and 2 patients required open conversion. Freedom from Type Ia endoleaks was 99.4% at 1, 2, 3 and 4 years. Freedom from Type IIIa and Type IIIb endoleaks were 100% and 100% (year 1), 100% and 99.6% (year 2), 99.4% and 99.6% (year 3), 99.4% and 99.6% (year 4) respectively. Freedom from all device-related reintervention (including Type II endoleaks) at 4 y was 86.8%. The AFX2 endograft appears to perform to a satisfactory standard in terms of patient centric outcomes in mid-term follow up. The Type Ia and Type III endoleaks rates at 4y appear to be within acceptable limits. Further follow up studies are warranted.

Ten-year single center experience in elective standard endovascular abdominal aortic aneurysm repair

BACKGROUND

Endovascular aneurysm repair (EVAR) has become the treatment of choice for abdominal aortic aneurysm (AAA), demonstrating excellent early outcomes. However, EVAR durability has been questioned in the long-term period. The aim of this study was to assess EVAR outcomes in terms of survival and freedom from re-intervention during a long-term period.

METHODS

All consecutive patients being treated, with elective standard EVAR, in a single tertiary center, were included between 2008 and 2018. Outcomes were defined as survival and freedom from re-intervention and were reported using Kaplan-Meyer lifetables. In subgroup analyses, sex, age (threshold at 65 and 80 years), neck diameter>28mm and type of fixation were also analyzed. Type of re-intervention and endoleak type I (ETIa) were also reported.

RESULTS

Five hundred and eight patients (94% males, mean age 72±7.3, mean AAA diameter 59±9mm) were included. The median follow-up was 3 years (range 0-10 years). The survival rate was 92.8% (SE 1.5%), 76.5% (SE 3.1%) and 41.6% (SE 6%), at 2, 5 and 10 years of follow-up, respectively. In total, 78 patients died; 8 deaths (8/75, 10%) were aneurysm related. In multivariate regression analysis, age (CI. 1.02-1.14; p=0.006) and ever tobacco use (CI. 1.02-6.12, P=0.045) were associated with the long-term mortality. Freedom from re-intervention was 96% (SE 1.1%), 93% (SE 1.8%), 85.5% (SE 5%) at 2, 5 and 9 years of follow-up. Limb occlusion was a common complication (n/n; 30% of re-intervention), particularly within the first 2 postoperative years. Six patients presented with rupture and were treated with open conversion. EVAR cases with supra-renal fixation graft presented lower rates of ETIa (CI. 76-87.27, P<0.001).

CONCLUSIONS

Elective standard EVAR is associated with good long-term survival showing low aneurysm-related mortality. Common risk factors such as advanced age and smoking are associated to higher mortality. The procedure presents low re-intervention rates, while limb occlusion is a complication presented within the first 2 postoperative years.

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

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

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

OBJECTIVE/BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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