New predictors of aneurysm sac behavior after endovascular aortic aneurysm repair

Systematic review of risk factors and outcomes of post-implantation syndrome following endovascular aortic repair

OBJECTIVE

Post implantation syndrome (PIS) is an early systemic inflammatory response following endovascular aortic repair (EVAR). The response is variable in patients and the clinical significance of PIS upon outcomes is unknown. This study aims to evaluate the incidence, risk factors, and prognostic implication of PIS.

METHODS

Systematic literature review and analysis was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and Cochrane guidelines of PubMed, Scopus, ClinicalTrials.gov, and the Cochrane Central Register of Controlled Trials. Eligible English-language studies regarding PIS after infrarenal EVAR were included, after removing duplicates.

RESULTS

After screening, 31 studies were included. A total of 2847 patients were reviewed, with mean age of 70.7 years, of which 2012 (90.4%) were male, with a pooled mean follow-up of 26.1 months. PIS was reported in 25.3% of cases, with mean aneurysm diameter of 56.4 cm. Polytetrafluoroethylene (PTFE) grafts were utilized in 794 patients (27.9%) with polyester in 1839 (64.6%). White blood cell count, C-reactive protein, interleukin (IL)-6, IL-8, and IL-10 levels were all significantly elevated postoperatively. Thirty-day outcomes included type I endoleak rate of 0.8%, type II endoleak rate of 1.7%, reintervention rate of 0.35%, and mortality rate of 0.25%. Subgroup pooled analysis of patients with PIS (n = 309) vs No-PIS (n = 691) revealed that polyester (n = 642), rather than PTFE (n = 234) grafts, were associated with a higher rate of PIS (94.8% vs 3.7%; P = .0001), White blood cell count was higher in the PIS group both preoperatively (7.61 vs 6.76 × 109/L; P = .04) and postoperatively (15.0 vs 9.8 × 109/L; P = .0007) and IL-6 levels were higher in the PIS group postoperatively (98.6 vs 25.2 pg/mL; P = .02). Aneurysm diameter and amount of chronic or new thrombus within the aneurysm sac was not identified as a risk factor for PIS. Pooled outcomes of patients with PIS vs No-PIS demonstrated a significantly higher rate of 30-day mortality (0.6% vs 0%; P = .03) and major adverse cardiac events (5.8% vs 0.43%; P < .0001) without any differences seen in reintervention or 30-day type I or type II endoleaks.

CONCLUSIONS

This systematic review suggests that polyester grafts are strongly associated with PIS compared with PTFE. Interestingly, this report is suggestive of an association between 30-day mortality and major adverse cardiac events and PIS. Given these clinical sequelae, consideration for use of PTFE over polyester grafts to reduce the incidence of PIS may be a simple step to improve overall outcome. Further, exploration of the relationship between inflammatory mediators associated with PIS and mortality and cardiac complications may engender deeper understanding of risks, leading to eventual mitigation of harm for patients experiencing PIS.

A stable aneurysm sac after endovascular aneurysm repair as a predictor for mortality, an in-depth analysis

OBJECTIVES

The aim of this study was to compare the long-term survival in patients with a stable aneurysmal sac and those with aneurysmal sac regression after endovascular aneurysm repair (EVAR) and to identify independent risk factors for aneurysmal sac regression and mortality after EVAR.

METHODS

We reviewed all patients who underwent EVAR between 2005 and 2018 with a computed tomography angiography available at 1-year follow-up. Aneurysm sac regression was defined as a diameter decrease of more than 10%. We used a multivariable regression to identify independent risk factors for sac regression. Kaplan-Meier analysis and Cox regression were done to test differences in 5-year mortality between a stable sac and sac regression.

RESULTS

The inclusion criteria were met by 325 patients, 185 in the sac regression group and 140 in the stable sac group. Multivariable logistic regression analysis showed that treatment for a ruptured aneurysm was an independent risk factor for aneurysmal sac regression (hazard ratio [HR], 0.26; 95% confidence interval [CI], 0.07-0.96). Age (HR, 1.05; 95% CI, 1.01-1.09), ischemic heart disease (HR, 1.94; 95% CI, 1.13-3.31), neck thrombus (HR, 2.72; 95% CI, 1.07-6.95), and a type II endoleak (HR, 19.21; 95% CI, 7.32-50.40) were independent risk factors for a stable aneurysm sac diameter. Multivariable Cox regression showed a significantly increased risk of mortality for patients with a stable aneurysm sac after EVAR (odds ratio, 2.25; 95% CI, 1.36-3.72). There was no significant difference in cause of death between the two groups.

CONCLUSION

A stable aneurysm sac after EVAR is associated with increased mortality. Age, ischemic heart disease, neck thrombus, and a type II endoleak are independent risk factors for a stable sac. However, a well-founded explanation for this finding is still lacking. Future research should be focussed on aggressive treatment of type II endoleaks and inflammatory processes as potential pathophysiological mechanisms.

A systematic review on anatomical predictors of abdominal aortic aneurysm remodeling after endovascular repair

OBJECTIVE

Long-term outcomes after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAAs) are inferior to open surgical repair with regard to reinterventions and late mortality. AAA sac remodeling after EVAR has been associated with endoleaks, reinterventions, and mortality. Therefore, predictors of AAA sac remodeling could indirectly give insight into long-term EVAR outcomes. This review aims to provide an overview of the evidence on anatomical predictors of positive and negative AAA sac remodeling after EVAR.

METHODS

A systematic literature review and analysis were conducted according to the PRISMA and Cochrane guidelines. PubMed and Scopus databases were searched using terms of AAA sac growth, shrinkage, and remodeling. Eligible articles were identified and only papers that included currently used endografts were included.

RESULTS

Nineteen studies that reported on a total of 27 anatomical parameters of the aortoiliac anatomy were included. Only 4 parameters were investigated by >5 studies, 7 parameters were investigated by 3-5 studies, 6 parameters were investigated by 2 studies, and 10 parameters were investigated by 1 study. For the presence of neck thrombus, 3 out of 4 studies reported similar results indicating that it may predict less AAA sac shrinkage. AAA thrombus, total AAA volume, flow-lumen volume, and the number of hostile neck parameters were only investigated by 2-3 studies, but they seem promising in predicting sac remodeling. For hostile neck anatomy, neck length, infrarenal neck angulation, and patency of the inferior mesenteric artery, no significant association with any category of AAA sac remodeling was found.

CONCLUSIONS

This review presents neck thrombus, AAA thrombus, number of hostile neck parameters, total AAA volume, and AAA flow-lumen volume as important anatomical features that are likely to play a role in AAA remodeling after endovascular repair that should be further explored using advanced imaging techniques. This review also showed that strong consistent evidence on anatomical predictors of AAA sac remodeling after EVAR is lacking. Therefore, further research with large patient groups on a broad range of predictors of AAA sac change after EVAR is needed to complement the current gap in the evidence.

Long Term Outcomes of Post-Implantation Syndrome After Endovascular Aneurysm Repair

OBJECTIVE

The aim of this study was to investigate the association between post-implantation syndrome (PIS) and long term outcomes, with emphasis on cardiovascular prognosis.

METHODS

One hundred and forty-nine consecutive patients undergoing EVAR in a tertiary institution were previously included in a study investigating the risk factors and short term consequences of PIS (defined as tympanic temperature ≥ 38°C and CRP > 10 mg/L, after excluding complications with an effect on inflammatory markers). This study was based on a prospectively maintained database. Survival status was derived from inquiry of civil registry database information and causes of death from the Dutch Central Bureau of Statistics. The primary endpoint was cardiovascular events. Secondary endpoints were overall and specific cause mortality (cardiovascular, ischaemic heart disease, AAA, and cancer related mortality). Aneurysm sac dynamics and occurrence of endoleaks were also analysed. Survival estimates were obtained using Kaplan-Meier plots and a multivariable model was constructed to correct for confounders.

RESULTS

The PIS incidence was 39% (58/149). At the time of surgery, patients had a mean age of 73 ± 7 years and were predominantly male. There were no baseline differences between the PIS and non-PIS groups. The median follow up was 6.4 years (3.2 - 8.3), similar in both groups (p = .81). There was no difference in cardiovascular events for PIS and non-PIS patients (p = .63). However, Kaplan-Meier plots suggest a trend towards a higher rate of cardiovascular events in PIS patients during the first years: freedom from cardiovascular events at one year was 94% vs. 89% and at three years 90% vs. 82%. No differences were found in overall and specific cause mortality. There was a higher rate of type II endoleaks for non-PIS patients (28% vs. 9%, p = .005). Sac dynamics were similar in both groups.

CONCLUSION

The results suggest that PIS is not associated with a statistically significantly higher risk of cardiovascular events. PIS had no impact on mortality. Lastly, PIS patients had fewer type II endoleaks, but sac dynamics were analogous.

Postimplantation syndrome in endovascular aortic aneurysm repair - a systematic review

Postimplantation syndrome (PIS) following endovascular aortic aneurysm repair (EVAR) is a poorly understood phenomenon occurring in the early post-operative course. The underlying aetiology, risk factors, clinical sequalae, and treatment options, are largely unknown. The lack of any standardised diagnostic criteria limits current research in this field. The MEDLINE database was interrogated using a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) search strategy. Five search terms were used; "postimplantation syndrome" AND "aneurysm", AND "infection", AND "complications", AND "biomarkers", AND "outcomes". 19 studies were included in the review process, reporting a 17.4%-39.0% incidence of PIS. IL-6 was the most commonly elevated biomarker in PIS vs. non-PIS patients. There was a higher incidence of PIS in patients who received polyester rather than expanded-polytetrafluoroethylene (ePTFE) grafts. There was a lower rate of type 2 endoleaks observed in patients who developed PIS. Early major adverse cardiovascular events (MACE) were higher in PIS patients, however there were no studies reporting long-term MACE. Length of stay was higher in PIS patients. Current data support the role of IL-6 as being key to the development of PIS following EVAR. Further work describing the effect that PIS has on long-term clinical outcomes is needed. Lack of standardised diagnostic criteria limit the reporting of PIS between centres, the criteria proposed by this review may resolve this.

Prognostic Value of Initial Aneurysmal Sac Regression after EVAR

BACKGROUND

The objective of the study was to evaluate the impact of initial aneurysmal sac reduction after endovascular aneurysm repair on the evolution of aneurysmal sac over follow-up.

METHODS

A retrospective cohort study was made of patients subjected to elective treatment between January 2005 and December 2014, with a minimum follow-up of 18 months. An analysis was made of the evolution of the aneurysmal sac according to its condition one year after surgery, defining of two groups: A (sac reduction) and B (stable sac). Follow-up by computed tomography (CT) angiography was made after one month and then every 6 months or annually, depending on the presence of endoleak.

RESULTS

A total of 128 patients were included. Fifty-one patients (39.8%) showed a significant decrease in diameter during the first year (group A), whereas 77 patients (60.2%) showed no initial decrease (group B). Preoperative CT angiography showed the patients in group A to have larger aneurysms (63.5 mm vs. 59.25; P = 0.048), a greater presence of posterior thrombus (68.6% vs. 30.7%; P < 0.001), and fewer patent lumbar vessels (56.9% vs. 83.1%; P = 0.001). The prevalence of endoleak at some point during follow-up was lower in group A (31.4% vs. 74% in group B; P < 0.001), and 100% of all aneurysmal growths were associated to the presence of endoleak. After 5 years, significant differences were observed in the growth-free rate (96.9% in group A vs. 85.2% in group B; hazard ratio [HR] 4.8 [1.1-21.4; P = 0.036]) and in the reintervention-free rate (95,7% vs. 84.6%; HR 6.6 [0.8-52.4; P = 0.07]). No reoperation in group A was due to type II endoleak.

CONCLUSIONS

The aneurysmal sac can be expected to take a favorable course in those cases characterized by initial aneurysmal sac reduction. These findings may imply a change in the follow-up protocol, even in cases with type II endoleak.