Open Abdominal Aortic Aneurysm Repair Is Associated with Higher Mortality Among Nonobese Patients and Higher Risk of Deep Wound Infections Among Obese Patients

Japanese single-center experience of abdominal aortic aneurysm repair over 20 years: should open or endovascular aneurysm repair be performed first?

PURPOSE

The present study analyzed the outcomes of our experience with abdominal aortic aneurysm (AAA) repair over 20 years using endovascular aortic repair (EVAR) with commercially available devices or open aortic repair (OAR) and reviewed our surgical strategy for AAA.

METHODS

From 1999 to 2019, 1077 patients (659 OAR, 418 EVAR) underwent AAA repair. The OAR and EVAR groups were compared retrospectively, and a propensity matching analysis was performed.

RESULTS

EVAR was first introduced in 2008. Our strategy was changed to an EVAR-first strategy in 2010. Beginning in 2018, this EVAR-first strategy was changed to an OAR-first strategy. After propensity matching, the overall survival in the OAR group was significantly better than that in the EVAR group at 10 years (p = 0.006). Two late deaths due to AAA rupture were identified in the EVAR group, although there were no significant differences between the OAR and EVAR groups with regard to the freedom from AAA-related death at 10 years. The rate of freedom from aortic events at 10 years was significantly higher in the OAR group than in the EVAR group (p < 0.0001).

CONCLUSION

The rates of freedom from AAA-related death in both the OAR and EVAR groups were favorable, and the rate of freedom from aortic events was significantly lower in the EVAR group than in the OAR group. Close long-term follow-up after EVAR is mandatory.

Associations between body mass index and all-cause mortality: A systematic review and meta-analysis

Fasting insulin and c-reactive protein confound the association between mortality and body mass index. An increase in fat mass may mediate the associations between hyperinsulinemia, hyperinflammation, and mortality. The objective of this study was to describe the "average" associations between body mass index and the risk of mortality and to explore how adjusting for fasting insulin and markers of inflammation might modify the association of BMI with mortality. MEDLINE and EMBASE were searched for studies published in 2020. Studies with adult participants where BMI and vital status was assessed were included. BMI was required to be categorized into groups or parametrized as non-first order polynomials or splines. All-cause mortality was regressed against mean BMI squared within seven broad clinical populations. Study was modeled as a random intercept. β coefficients and 95% confidence intervals are reported along with estimates of mortality risk by BMIs of 20, 30, and 40 kg/m2 . Bubble plots with regression lines are drawn, showing the associations between mortality and BMI. Splines results were summarized. There were 154 included studies with 6,685,979 participants. Only five (3.2%) studies adjusted for a marker of inflammation, and no studies adjusted for fasting insulin. There were significant associations between higher BMIs and lower mortality risk in cardiovascular (unadjusted β -0.829 [95% CI -1.313, -0.345] and adjusted β -0.746 [95% CI -1.471, -0.021]), Covid-19 (unadjusted β -0.333 [95% CI -0.650, -0.015]), critically ill (adjusted β -0.550 [95% CI -1.091, -0.010]), and surgical (unadjusted β -0.415 [95% CI -0.824, -0.006]) populations. The associations for general, cancer, and non-communicable disease populations were not significant. Heterogeneity was very large (I2  ≥ 97%). The role of obesity as a driver of excess mortality should be critically re-examined, in parallel with increased efforts to determine the harms of hyperinsulinemia and chronic inflammation.

Association Between Obesity and Outcomes Following Endovascular Aneurysm Repair

BACKGROUND

Obesity is prevalent in patients with abdominal aortic aneurysms (AAA). There is an association between increasing body mass index (BMI) and increased overall cardiovascular mortality and morbidity. This study aims to assess the difference in mortality and complication rates between normal weight (NW), overweight (OW), and obese patients undergoing endovascular aneurysm repair (EVAR) for infrarenal AAA.

METHODS

This is a retrospective analysis of consecutive patients undergoing EVAR for AAA between January 1998 and December 2019. Weight classes were defined as: BMI<18.5 kg/m², underweight; BMI 18.5-24.9 kg/m², NW; BMI 25.0-29.9 kg/m², OW; BMI 30.0-39.9 kg/m², obese; BMI>39.9 kg/m² morbidly obese. Primary outcomes were long-term all-cause mortality and freedom from reintervention. Secondary outcome was aneurysm sac regression (defined as a reduction in sac diameter of 5 mm or more). Kaplan-Meier survival estimates and mixed model analysis of variance were used.

RESULTS

The study included 515 patients (83% males, mean age 77 ± 8 years) with a mean follow-up of 3.8 ± 2.8 years. In terms of weight class, 2.1% (n = 11) were underweight, 32.4% (167) were NW, 41.6% (n = 214) were OW, 21.2% (n = 109) were obese, and 2.7% (n = 14) were morbidly obese. Obese patients were younger (mean difference -5.0 years) but had a higher prevalence of diabetes mellitus (33.3% vs. 10.6% for NW) and dyslipidemia (82.4% vs. 60.9% for NW). Obese patients had similar freedom from all-cause mortality (88%) compared to OW (78%) and NW (81%) patients. The same findings were evident for freedom from reintervention where obese (79%) was similar to OW (76%) and NW (79%). At a mean follow-up of 5.1 ± 0.4 years, sac regression was observed similarly across weight classes at 49.6%, 50.6%, and 51.8% for NW, OW, and obese, respectively (P = 0.501). There was a significant difference in mean AAA diameter pre- and post-EVAR [F(2,318) = 24.37, P < 0.001] across weight classes. NW [mean reduction 4.8 mm (2.0-7.6 mm, P < 0.001)], OW [mean reduction 3.9 mm (1.5-6.3 mm, P < 0.001)], and obese [mean reduction 5.7 mm (2.3-9.1 mm, P < 0.001)] achieved similar reductions.

CONCLUSIONS

Obesity was not associated with increased mortality or reintervention in patients undergoing EVAR. Obese patients achieved similar rates of sac regression on imaging follow-up.

Effect of Body Mass Index on Early Outcomes of Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

This study compares the presentation, management, and outcomes of patients undergoing endovascular abdominal aortic aneurysm repair (EVAR), based on their weight status as defined by their body mass index (BMI).

METHODS

Patients with primary EVAR for ruptured and intact abdominal aortic aneurysm (AAA) were identified in the National Surgical Quality Improvement Program database (2016-2019). Patients were categorized by weight status (underweight: BMI < 18.5 kg/m², normal weight: 18.5-24.9 kg/m², overweight: 25-29.9 kg/m², Obese I: 30-34.9 kg/m², Obese II: 35-39.9 kg/m², Obese III: > 40 kg/m²). Preoperative characteristics and 30-day outcomes were compared.

RESULTS

Of 3,941 patients, 4.8% were underweight, 24.1% normal weight, 37.6% overweight, and 22.5% with Obese I, 7.8% Obese II, and 3.3% Obese III status. Underweight patients presented with larger (6.0 [5.4-7.2] cm) and more frequently ruptured (25.0%) aneurysms than normal weight patients (5.5 [5.1-6.2] cm and 4.3%, P < 0.001 for both). Pooled 30-day mortality was worse for underweight (8.5%) compared to all other weight status (1.1-3.0%, P < 0.001), but risk-adjusted analysis demonstrated that aneurysm rupture (odds ratio [OR] 15.9, 95% confidence interval [CI] 8.98-28.0) and not underweight status (OR 1.75, 95% CI 0.73-4.18) accounted for increased mortality in this population. Obese III status was associated with prolonged operative time and respiratory complications after ruptured AAA, but not 30-day mortality (OR 0.82, 95% CI 0.25-2.62).

CONCLUSIONS

Patients at either extreme of the BMI range had the worst outcomes after EVAR. Underweight patients represented only 4.8% of all EVARs, but 21% of mortalities, largely attributed to higher incidence of ruptured AAA at presentation. Severe obesity, on the other hand, was associated with prolonged operative time and respiratory complications after EVAR for ruptured AAA. BMI, as an independent factor, was however not predictive of mortality for EVAR.

Mannitol Use is Renal Protective in Patients with Chronic Kidney Disease Requiring Suprarenal Aortic Clamping

OBJECTIVES

Objective: Mannitol is often administered during open juxtarenal or suprarenal aortic surgery to prevent ischemic injury to the kidneys. Prior evidence evaluating the benefits of intraoperative mannitol in reducing ischemia/reperfusion injury is conflicting and largely based on small, retrospective series. The aim of this study was to evaluate the effect of mannitol in preventing postoperative hemodialysis in patients undergoing open abdominal aortic aneurysm (AAA) repair where proximal control involved temporary renal ischemia.

METHODS

Methods: The Society for Vascular Surgery Quality Initiative database was queried for all patients undergoing elective open AAA repair between 2003 and 2020. Patients were included in the current analysis if the proximal aortic clamp was placed above at least one renal artery. Chronic kidney disease (CKD) was defined as Cr >1.8mg/dL. Primary endpoints were 30-day major morbidity (myocardial infarction, respiratory complications, lower extremity or intestinal ischemia, and the need for temporary or permanent hemodialysis) and mortality. Comparisons were made between the mannitol and non-mannitol cohorts and stratified by the presence of pre-existing CKD.

RESULTS

Results: During the study period, 4,156 patients underwent elective open AAA repair requiring clamp placement above one (32.7%) or both (67.3%) renal arteries; 182 patients (4.4%) had pre-existing CKD. Overall, 69.8% of patients received mannitol during their surgery. Mannitol was more frequently used in cases involving clamp placement above both renal arteries (70.3%) than one renal artery (61.5%). While prolonged ischemia time (greater than 40 minutes) was associated with higher risk of post-operative dialysis in patients without CKD, it was not significant in patients with baseline CKD. On univariate analysis, mannitol use in patients with CKD was associated with lower risk of post-operative dialysis (p=0.005). This remained significant on multivariate analysis (p=0.008). Mannitol use did not appear to confer renal protective effects in patients without baseline CKD.

CONCLUSIONS

Conclusion: Mannitol use was associated with a decreased risk of need for post-operative hemodialysis in patients with CKD undergoing suprarenal aortic clamping for open aneurysm repair. In appropriately selected patients, particularly those with underlying renal insufficiency, mannitol may confer a renal protective effect in open repair of pararenal AAA requiring suprarenal clamping.

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.