Abdominal aortic aneurysm repair in obese patients: improved outcome after endovascular treatment compared with open surgery

Impact of class of obesity on clinical outcomes following fenestrated-branched endovascular aneurysm repair

BACKGROUND

Obesity represents a prevalent and escalating health concern among vascular surgery patients. Evidence pertaining to the influence of body mass index (BMI) on clinical outcomes after fenestrated-branched endovascular aneurysm repair (B/FEVAR) remains unclear. This study aims to assess the effect of obesity on short- and midterm clinical outcomes among individuals undergoing B/FEVAR.

METHODS

This was a single-center retrospective analysis of all patients who underwent B/FEVAR from 2007 to 2020, with a median follow-up of 3.3 years (interquartile range, 1.6-5.3 years). Obesity was defined as a BMI of ≥30 kg/m2. Patients were divided into nonobese (NO) and obese cohorts according to their BMI. Outcomes were compared between the two groups subsequently.

RESULTS

A total of 264 patients, 96 obese and 168 NO, were included. Patients with obesity were younger (72.8 ± 6.9 years vs 76.0 ± 7.3 years; P < .001), but had a higher prevalence of diabetes mellitus (27.1% vs 12.0%; P = .01) and dyslipidemia (80.2% vs 68.5%; P = .03). Both cohorts had similar rates of percutaneous access (37.5% for obese vs 35.1%; P = .7), and no significant differences in the rate of conversion to open access (8.3% for obese vs 4.2% for NO; P = .16). Technical success was similar between the cohorts (89% for obese vs 86%; P = .59). Major adverse events (MAEs) were higher in the NO group (13.1% vs 4.2%; P = .02). Patients in the obese cohort suffered more access site related infections (7.3% vs 1.2%; P = .01). All-cause mortality over 5 years was significantly higher in the NO group (35.1% vs 21.9%; P = .02). No statistical differences were found in spinal cord injury or dialysis requirement rates. Furthermore, on follow-up at 5 years, endoleak, branch instability, and reintervention rates were not statistically different between the two cohorts.

CONCLUSIONS

Patients with obesity are on average younger; however, they were more likely to suffer access site infections compared with NO patients. They had increased survival rates on follow-up, although rates of reinterventions and endoleaks were similar between the two cohorts. Our study demonstrates that, despite higher comorbidities, patients with obesity had similar intraoperative success with decreased postoperative mortality; however, access site infections remains a significant clinical concern.

New Measures, Old Conclusions: Obesity Does Not Worsen Outcomes after Elective Abdominal Aortic Aneurysm Repair

Background  The “obesity paradox,” whereby the body mass index (BMI) mortality curve is “U-shaped,” is a well-studied phenomenon in vascular surgery. However, there has been an overreliance on BMI as the measure of obesity, which has shown to poorly correlate with clinical outcomes. Robust measures such as waist-hip ratio (WHR) have been suggested as a more accurate marker reflecting central obesity.

Objectives  The objectives of this study were to evaluate the correlation between BMI and WHR on postoperative morbidity and mortality after elective abdominal aortic aneurysm (AAA) repair.

Methods  Data were collected from the Leeds Vascular Institute between January 2006 and December 2016. The primary outcome was mortality and secondary outcomes included length of stay (LOS) and all-cause readmission. Binary logistic regression, linear regression, and correlation analysis were used to identify associations between BMI and WHR in relation to outcome measures.

Results  After exclusions, 432 elective AAA repairs (281 open surgical repair [OSR] and 151 endovascular aneurysm repairs [EVARs]) were identified to be eligible for the study. The combined 30-day and 4-year mortality was 1.2 and 20.1%, respectively. The 30-day readmission rate was 3.9% and the average LOS was 7.33 (standard deviation 18.5) days. BMI data was recorded for 275 patients (63.7%) and WHR for 355 patients (82.2%). Logistic regression analysis highlighted no association between BMI and WHR with mortality, readmission, or LOS following OSR or EVAR.

Conclusion  The results of this study suggest patients should not be denied treatment for AAA based on obesity alone.

A systematic review and meta-analysis evaluating the impact of obesity on outcomes of abdominal aortic aneurysm treatment

OBJECTIVE

We sought to evaluate the impact of obesity on perioperative mortality and complication rates in patients undergoing endovascular aortic repair (EVAR) and open surgical repair (OSR) for abdominal aortic aneurysms (AAA).

METHODS

A systematic review of all studies reporting AAA treatment perioperative (30 day) outcomes in obese patients (body mass index ≥30 kg/m²). The primary outcome was 30 day mortality. Secondary outcomes included: cardiac complications, respiratory complications, wound complication, renal complications, and neurological complications at 30 days. These outcomes were pooled for meta-analysis. Analysis first compared obese versus nonobese patients undergoing EVAR and OSR then compared EVAR to OSR in obese patients.

RESULTS

We identified 7 observational studies with 14,971 patients (11,743 EVAR, 3228 OSR). Obese patients undergoing EVAR had lower 30 day mortality (1.5%) compared to nonobese patients (2.2%) (OR 0.69; 95% CI 0.50-0.96; p=0.03; I²= 0%; Grade of evidence: low). In OSR, obese patients (5.0%) had similar 30 day mortality to nonobese patients (5.7%) (OR 0.92; 95% CI 0.70-1.20; p=0.54; I²=0%; Grade of evidence: low). Wound complications were higher in obese patients undergoing OSR (OR 2.30; 95% CI 1.74-3.06; p<0.001; I²=0%; Grade of evidence: low). EVAR was associated with a lower 30 day mortality (1.5%) compared to OSR (5.0%) in obese patients (OR 0.23; 95% CI 0.12-0.46; p<0.001; I²= 38%; Grade of evidence: low). Cardiac, respiratory, wound, renal and neurological complications were also reduced in EVAR.

CONCLUSIONS

Obese patients have lower 30 day mortality in EVAR compared to nonobese patients. In OSR, obese patients had similar 30 day mortality but higher wound complications compared to nonobese patients. Obese patients otherwise have similar cardiopulmonary complication rates compared to nonobese patients in both EVAR and OSR. EVAR offers lower 30 day mortality and morbidity compared to OSR in obese patients. This study suggests that EVAR is superior to OSR in obese patients.

Association of body mass index with outcomes after thoracic endovascular aortic repair in the vascular quality initiative

OBJECTIVE

Although several studies have evaluated the impact of obesity on outcomes after abdominal aortic aneurysm repair, literature examining this association in thoracic endovascular aortic repair (TEVAR) is sparse. Here, we use a multi-institutional, international database to assess the role of body mass index (BMI) on adverse outcomes in patients who underwent TEVAR for descending thoracic aortic aneurysms (DTAA) and type B dissections (TBD).

METHODS

A retrospective review of all patients who underwent TEVAR for DTAA or TBD from August 2014 to August 2020 was performed. Patients who were underweight (BMI <18.5 kg/m²) or obese (BMI ≥30 kg/m²) were compared with those of normal weight (≥18.5 to <30 kg/m²). Adjustment for confounding was done with multivariable logistic regression or Cox proportional hazards regression as appropriate for studying postoperative or 1-year outcomes. Primary outcomes were 30-day and 1-year mortality. Other outcomes included any postoperative complication, stroke, and spinal cord ischemia.

RESULTS

A total of 3423 participants were included in the study, of whom 3.3% (n = 113) were underweight, 65.9% (n = 2253) had normal weight, and 30.8% (n = 1053) were obese. Compared with normal weight, there was no significant difference in 30-day mortality in underweight patients (odds ratio [OR], 1.81; 95% confidence interval [CI], 0.80-4.14; P = .156). Obese patients who underwent TEVAR for TBD had a 2.7-fold increase in the odds of 30-day mortality compared with normal weight (OR, 2.67; 95% CI, 1.52-4.68; P = .001). Obese and normal weight patients with DTAA had equivalent odds of 30-day mortality (OR, 1.32; 95% CI, 0.79-2.23; P = .292). The adjusted hazard of 1-year mortality was 2-fold higher in underweight patients compared with normal weight (hazard ratio, 2.15; 95% CI, 1.41-3.29; P < .001), driven by a higher risk of mortality among patients with thoracic aortic aneurysm (OR, 2.62; 95% CI, 1.63-4.21; P < .001). There was no significant difference in 1-year mortality risk between normal weight and obesity in both DTAA (OR, 0.77; 95% CI, 0.54-1.09; P = .146) and TBD (OR, 1.26; 95% CI, 0.85-1.86; P = .248).

CONCLUSIONS

In this study, obese patients who underwent TEVAR for DTAA had comparable 30-day and 1-year mortality risk as normal weight individuals. Obese patients who underwent TEVAR for TBD demonstrated a 2.7-fold increase in the odds of 30-day mortality, but equivalent mortality risk as normal weight patients at 1 year. TEVAR represents a safe minimally invasive option for treatment of DTAA in obese patients. Future work should be directed toward minimizing perioperative mortality among patients with TBD to optimize TEVAR outcomes.

Effect of obesity on radiation exposure, quality of life scores, and outcomes of fenestrated-branched endovascular aortic repair of pararenal and thoracoabdominal aortic aneurysms

BACKGROUND

The aim of the present study was to assess the effect of obesity on procedural metrics, radiation exposure, quality of life (QOL), and clinical outcomes of fenestrated-branched endovascular aortic repair (FB-EVAR) of pararenal and thoracoabdominal aortic aneurysms.

METHODS

We reviewed the clinical data from 334 patients (236 men; mean age, 75 ± 8 years) enrolled in a prospective nonrandomized study to evaluate FB-EVAR from 2013 to 2019. The patients were classified using the body mass index (BMI) as obese (BMI ≥30 kg/m²) or nonobese (BMI <30 kg/m²). QOL questionnaires (short-form 36-item questionnaire) and imaging studies were obtained preoperatively and at 2 months and 6 months postoperatively, and annually thereafter. The procedures were performed using two different fixed imaging systems. The end points included procedural metrics (ie, total operative time, fluoroscopic time, contrast volume), radiation exposure, technical success, 30-day mortality, and major adverse events, QOL changes, freedom from target vessel instability, freedom from reintervention, and patient survival.

RESULTS

The aneurysm extent was a pararenal aortic aneurysm in 117 patients (35%) and a thoracoabdominal aortic aneurysm in 217 patients (65%). Both groups had similar demographics, cardiovascular risk factors, and aneurysm extent, except for a greater incidence of hyperlipidemia and diabetes among the obese patients (P < .05). No significant differences were found in the procedural metrics or intraprocedural complications between the groups, except that the obese patients had greater radiation exposure than the nonobese patients (mean, 2.5 vs 1.6 Gy; P < .001), with the highest radiation exposure in those obese patients who had undergone the procedure using system 1 (fusion alone) instead of system 2 (fusion and digital zoom; mean, 4.1 vs 1.5 Gy; P < .001). Three patients had died within 30 days (0.8%), with no difference in mortality or major adverse events between the groups. The mental QOL scores had improved in the obese group at 2 and 12 months compared with the nonobese patients, with persistently higher scores up to 3 years. At 3 years, the obese and nonobese patients had a similar incidence of freedom from target vessel instability (74% ± 6% vs 80% ± 3%; P = .99, log-rank test), freedom from reintervention (66% ± 6% vs 73% ± 4%; P = .77, log-rank test), and patient survival (83% ± 5% vs 75% ± 4%; P = .16, log-rank test).

CONCLUSIONS

FB-EVAR was performed with high technical success and low mortality and morbidity, with no significant differences between the obese and nonobese patients. The procedural metrics and outcomes were similar, with the exception of greater radiation exposure among obese patients, especially for the procedures performed using system 1 with fusion alone compared with system 2 (fusion and digital zoom). Obese patients had higher QOL mental scores at 2 and 12 months, with a similar reintervention rate, target vessel outcomes, and survival compared with nonobese patients.

The Obesity-associated Risk in Open and Endovascular Repair of Abdominal Aortic Aneurysm

:

The rising pandemic of obesity in modern society should direct attention to a more comprehensive approach to abdominal aortic aneurysm (AAA) treatment in the affected population. Although overweight patients are considered prone to increased surgical risk, studies on the subject did not confirm or specify the risks well enough.

:

Associated comorbidities inevitably lead to a selection bias leaning towards endovascular abdominal aortic repair (EVAR), as a less invasive treatment option, which makes it hard to single out obesity as an independent risk factor. The increased technical difficulty often results in prolonged procedure times and increased blood loss. Several smaller studies and two analyses of national registries, including 7935 patients, highlighted the advantages of EVAR over open repair (OR) of abdominal aortic aneurysm, especially in morbidly obese population (relative risk reduction up to 47%). On the other hand, two other studies with 1374 patients combined, concluded that EVAR might not have an advantage over OR in obese patients (P = 0.52). Obesity is an established risk factor for wound infection after both EVAR and OR, which is associated with longer length of stay, subsequent major operations, and a higher rate of graft failure. Percutaneous EVAR technique could present a promising solution to reducing this complication.

:

EVAR seems like a more feasible treatment option than OR for obese patients with AAA, due to lower overall morbidity and mortality rates, as well as reduced wound-related complication rates. However, there is a clear lack of high-quality evidence on the subject, thus future prospective trials are needed to confirm this advantage.

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.

Outcomes after elective abdominal aortic aneurysm repair in obese versus nonobese patients

OBJECTIVE

Obesity is a worldwide epidemic, particularly in Western society. It predisposes surgical patients to an increased risk of adverse outcomes. The aim of our study was to use a nationally representative vascular database and to compare in-hospital outcomes in obese vs nonobese patients undergoing elective open aortic repair (OAR) and endovascular aneurysm repair (EVAR).

METHODS

All patients undergoing elective abdominal aortic aneurysm repair were identified in the Vascular Quality Initiative database (2003-2017). Obesity was defined as body mass index ≥30 kg/m². Univariable (Student t-test and χ² test) and multivariable (logistic regression) analyses were implemented to compare in-hospital mortality and any major complications (wound infection, renal failure, and cardiopulmonary failure) in obese vs nonobese patients.

RESULTS

We identified a total of 33,082 patients undergoing elective OAR (nonobese, n = 4605 [72.4%]; obese, n = 1754 [27.6%]) and EVAR (nonobese, n = 18,338 [68.6%]; obese, n = 8385 [31.4%]). Obese patients undergoing OAR and EVAR were relatively younger compared with nonobese patients (mean age [standard deviation], 67.55 [8.26] years vs 70.27 [8.30] years and 71.06 [8.22] years vs 74.55 [8.55] years), respectively; (both P < .001). Regardless of approach, obese patients had slightly longer operative time (OAR, 259.02 [109.97] minutes vs 239.37 [99.78] minutes; EVAR, 138.27 [70.64] minutes vs 134.34 [69.98] minutes) and higher blood loss (OAR, 2030 [1823] mL vs 1619 [1642] mL; EVAR, 228 [354] mL vs 207 [312] mL; both P < .001). There was no significant difference in mortality between the two groups undergoing OAR and EVAR (OAR, 2.9% vs 3.2% [P = .50]; EVAR, 0.5% vs 0.6% [P = .76]). On multivariable analysis, obese patients undergoing OAR had 33% higher odds of renal failure (adjusted odds ratio [OR], 1.33; 95% confidence interval [CI], 1.09-1.63; P = .006) and 75% higher odds of wound infections (adjusted OR, 1.75; 95% CI, 1.11-2.76; P = .02) compared with nonobese patients. However, in patients undergoing EVAR, no association was seen between obesity and any major complications. A significant interaction was found between obesity and surgical approach in the event of renal failure, in which obese patients undergoing OAR had significantly higher odds of renal failure compared with those in the EVAR group (OR_interaction, 1.36; 95% CI, 1.05-1.75; P = .02).

CONCLUSIONS

Using a large nationally representative database, we demonstrated an increased risk of renal failure and wound infections in obese patients undergoing OAR compared with nonobese patients. On the other hand, obesity did not seem to increase the odds of major adverse outcomes in patients undergoing EVAR. Further long-term prospective studies are needed to verify the effects of obesity after abdominal aortic aneurysm repair and the implications of these findings in clinical decision-making.

Effect of craniotomy on oxidative stress and its effect on plasma L-carnitine levels

OBJECTIVE

to investigate the impact of craniotomy on oxidative stress and its effect on levels of plasma L-carnitine (LC).

METHODS

plasma levels of reactive oxygen species, superoxide dismutase (SOD), glutathion peroxidase (GSH-Px), catalase (CAT), total antioxidative capacity (T-AOC), and thiobarbituric acid reactive substances (TBARS) were measured in 34 patients (26 males and 8 females, mean age 47.7 ± 6.7 years) before and after craniotomy. Plasma levels of LC, acetyl-L-carnitine (ALC), and propionyl-L-carnitine (PLC) were also measured before and after the craniotomy.

RESULTS

the plasma concentrations of SOD, GSH-Px, CAT, and T-AOC within the first 4 h after craniotomy were lower than their baseline values (P < 0.05). There were no statistically significant differences in the mean plasma levels of SOD, GSH-Px, CAT, or T-AOC between the baseline and 24 h post-operative values. The level of TBARS at 4 h after the craniotomy was lower than the pre-operative level (P < 0.05), but the 24 h post-operative value was similar to the baseline concentration (P > 0.05). Plasma levels of LC, ALC, and PLC were lower after the craniotomy (P < 0.05), but these levels returned to the baseline levels 24 h after the operation.

CONCLUSIONS

craniotomy and the associated procedures for surgery/anesthesia temporarily reduce antioxidant activity and plasma levels of L-carnitine.

Obesity is not an Independent Risk Factor for Adverse Perioperative and Long-Term Clinical Outcomes Following Open AAA Repair or EVAR

Objectives: Moderate (body mass index [BMI] ≥30) and morbid obesity (BMI ≥35) is increasing at an alarming rate in vascular surgery patients. The objective of this study was to determine the impact of obesity on perioperative and long-term clinical outcomes following open abdominal aortic aneurysm (AAA) repair or endovascular aneurysm repair (EVAR). Methods: This review includes patients that underwent open AAA repair (n = 403) or EVAR (n = 223) from 1999 to 2009. Specific patient characteristics such as comorbid diseases, medications, and body mass index (BMI) were assessed. Specific perioperative outcomes such as length of stay, myocardial infarctions, and mortality were reviewed. In addition, long-term outcomes such as rates of reintervention, permanent renal dysfunction, and mortality beyond 30 days were also assessed. Results: The incidence of obesity in open AAA patients was 25.3% (documented incidence 1.5%) and for EVAR was 24.6% (documented incidence 4%). Moderate and morbid obesity was associated with longer intensive care unit (ICU) admissions for both open AAA or EVAR patients ( P < .05). However, no significant differences in perioperative outcomes in terms of overall length of stay, myocardial infarction, acute renal failure, wound infections, or mortality were noted between obese and nonobese patients underoing open AAA repair or EVAR ( P > .05). Similarly, moderate and morbid obesity was not associated with significant differences in rates of reintervention, permanent renal dysfunction, and mortality beyond 30 days for patients undergoing open AAA repair or EVAR ( P > .05). Conclusions: The results of this study indicate that moderate and morbid obesity are not independently associated with adverse perioperative and long-term clinical outcomes for patients undergoing open AAA repair or EVAR. Therefore, either open AAA repair or EVAR can be accomplished safely in moderately obese and morbidly obese patients.

Pathophysiology and epidemiology of abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are found in up to 8% of men aged >65 years, yet usually remain asymptomatic until they rupture. Rupture of an AAA and its associated catastrophic physiological insult carries overall mortality in excess of 80%, and 2% of all deaths are AAA-related. Pathologically, AAAs are associated with inflammation, smooth muscle cell apoptosis, and matrix degradation. Once thought to be a consequence of advanced atherosclerosis, accruing evidence indicates that AAAs are a focal representation of a systemic disease of the vasculature. Risk factors for AAAs include increasing age, male sex, smoking, and low HDL-cholesterol levels. Familial associations exist and although susceptibility genes have been described on the basis of candidate-gene studies, robust genetic studies have failed to discover causative gene mutations. The surgical management of AAAs has been revolutionized by minimally invasive endovascular repair. Ongoing randomized trials will establish whether endovascular repair confers a survival advantage over open surgery for patients with a ruptured AAA. In many countries, centralization of vascular surgical services has largely been driven by the improved outcomes of elective aneurysm surgery in specialized centers, the widespread adoption of endovascular techniques, and the introduction of screening programs.

Endovascular Abdominal Aortic Aneurysm Repair (EVAR) Procedures: Counterbalancing the Benefits With the Costs

Endovascular abdominal aortic aneurysm (AAA) repair (EVAR) is associated with lower 30-day mortality rates compared with open repair. Despite that, there are no significant differences in mortality rates between the two procedures at 2 years. On the other hand, EVAR is associated with considerably higher costs compared with open repair. The lack of significant long-term differences between the two procedures together with the substantially higher cost of EVAR may question the appropriateness of EVAR as an alternative to open surgical repair in patients fit for surgery. With several thousands of AAA procedures performed worldwide, the employment of EVAR for the management of all AAAs irrespective of the patient’s surgical risk may hold implications for several national health economies. The lower perioperative mortality and morbidity rates associated with EVAR should thus be counterbalanced against the considerable costs of these procedures.