Comparison of open transabdominal AAA repair with endovascular AAA repair in reduction of postoperative stress response

Assessment of the Risk Analysis Index for Prediction of Mortality, Major Complications, and Length of Stay in Patients who Underwent Vascular Surgery

BACKGROUND

Frailty is a risk factor for adverse postoperative outcomes. We aimed to test the performance of a prospectively validated frailty measure, the Risk Analysis Index (RAI) in patients who underwent vascular surgery and delineate the additive impact of procedure complexity on surgical outcomes.

METHODS

We queried the 2007-2013 American College of Surgeons National Surgical Quality Improvement Program database to identify 6 major elective vascular procedure categories (carotid revascularization, abdominal aortic aneurysm [AAA] repair, suprainguinal revascularization, infrainguinal revascularization, thoracic aortic aneurysm [TAA] repair, and thoracoabdominal aortic aneurysm [TAAA] repair). We trained and tested logistic regression models for 30-day mortality, major complications, and prolonged length of stay (LOS). The first model, "RAI," used the RAI alone; "RAI-Procedure (RAI-P)" included procedure category (e.g., AAA repair) and procedure approach (e.g., endovascular); "RAI-Procedure Complexity (RAI-PC)" added outpatient versus inpatient surgery, general anesthesia use, work relative value units (RVUs), and operative time.

RESULTS

The RAI model was a good predictor of mortality for vascular procedures overall (C-statistic: 0.72). The C-statistic increased with the RAI-P (0.78), which further improved minimally, with the RAI-PC (0.79). When stratified by procedure category, the RAI predicted mortality well for infrainguinal (0.79) and suprainguinal (0.74) procedures, moderately well for AAA repairs (0.69) and carotid revascularizations (0.70), and poorly for TAAs (0.62) and TAAAs (0.54). For carotid, infrainguinal, and suprainguinal procedures, procedure complexity (RAI-PC) had little impact on model discrimination for mortality, did improve discrimination for AAAs (0.84), TAAs (0.73), and TAAAs (0.80). Although the RAI model was not a good predictor for major complications or LOS, discrimination improved for both with the RAI-PC model.

CONCLUSIONS

Frailty as measured by the RAI was a good predictor of mortality overall after vascular surgery procedures. Although the RAI was not a strong predictor of major complications or prolonged LOS, the models improved with the addition of procedure characteristics like procedure category and approach.

Neutrophil-lymphocyte ratio predicts disease severity and outcome after lower extremity procedures

OBJECTIVE

Neutrophil-lymphocyte ratio (NLR) has been associated with inferior outcomes after lower extremity interventions. NLR has been associated with systemic inflammation and atherosclerotic burden. We examined NLR, severity of peripheral artery disease (PAD), and outcomes after endovascular or open surgical procedures.

METHODS

Inpatients undergoing lower extremity procedures (2008-2016) were selected from Cerner Health Facts database (Cerner Corporation, North Kansas City, Mo) using International Classification of Diseases, Ninth Revision procedure codes. Disease severity was grouped into claudication, rest pain, and tissue loss. Outcomes were identified using International Classification of Diseases, Ninth Revision codes. NLR was calculated preoperatively and postoperatively. A χ² analysis and multivariable logistic regression were performed. A receiver operating characteristic curve analysis was used to determine the cutoff for preoperative (low, <3.65; high, ≥3.65) and postoperative (low, <5.96; high, ≥5.96) NLR values.

RESULTS

There were 3687 patients evaluated; 2183 (59%) underwent endovascular procedures and 1504 (41%) had open procedures. Compared with black patients, claudication was more frequent in white patients (81.7% vs 72.7%; P < .0001), and tissue loss was less common (12.9% vs 20.9%; P < .0001). NLR values were higher for patients with tissue loss than for patients with rest pain or claudication (4.89, 4.33, and 3.11, respectively; P < .0001). Open procedures were associated with higher postoperative NLR values than endovascular procedures (6.8 vs 5.2; P < .0001). Mean preoperative and postoperative NLR values were greater in patients with more severe PAD. Multivariable analysis demonstrated that preoperative high NLR was strongly associated with in-hospital death (odds ratio [OR], 5.4; 95% confidence interval [CI], 1.68-17.07), cardiac complications (OR, 2.9; 95% CI, 1.57-5.40), amputation (OR, 2.5; 95% CI, 1.65-3.87), renal failure (OR, 1.9; 95% CI, 1.18-2.93), respiratory complications (OR, 1.7; 95% CI, 1.09-2.76), and prolonged length of stay (OR, 1.9; 95% CI, 1.89-3.71).

CONCLUSIONS

Preoperative and postoperative NLR significantly increases with disease severity for PAD, providing further evidence of NLR as a biomarker of a patient's systemic inflammatory state. After adjustment for confounders, NLR still remained strongly associated with death and other adverse outcomes after intervention for PAD. Further study of the clinical association of NLR with other vascular disorders, such as symptomatic carotid stenosis and symptomatic and ruptured aortic aneurysmal disease, is planned to guide individualized treatment to prevent stroke or aneurysm rupture.

Cytokines as biomarkers of inflammatory response after open versus endovascular repair of abdominal aortic aneurysms: a systematic review

The repair of an abdominal aortic aneurysm (AAA) is a high-risk surgical procedure related to hormonal and metabolic stress-related response with an ensuing activation of the inflammatory cascade. In contrast to open repair (OR), endovascular aortic aneurysm repair (EVAR) seems to decrease the postoperative stress by offering less extensive incisions, dissection, and tissue manipulation. However, these beneficial effects may be offset by the release of cytokines and arachidonic acid metabolites during intra-luminal manipulation of the thrombus using catheters in endovascular repair, resulting in systemic inflammatory response (SIR), which is clinically called post-implantation syndrome. In this systematic review we compared OR with EVAR in terms of the post-interventional inflammatory response resulting from alterations in the circulating cytokine levels. We sought to summarize all the latest evidence regarding post-implantation syndrome after EVAR. We searched Medline (PubMed), ClinicalTrials.gov and the Cochrane library for clinical studies reporting on the release of cytokines as part of the inflammatory response after both open/conventional and endovascular repair of the AAA. We identified 17 studies examining the cytokine levels after OR versus EVAR. OR seemed to be associated with a greater SIR than EVAR, as evidenced by the increased cytokine levels, particularly IL-6 and IL-8, whereas IL-1β, IL-10 and TNF-α showed conflicting results or no difference between the two groups. Polyester endografts appear to be positively correlated with the incidence of post-implantation syndrome after EVAR. Future large prospective studies are warranted to delineate the underlying mechanisms of the cytokine interaction in the post-surgical inflammatory response setting.

Risk stratification by pre-operative cardiopulmonary exercise testing improves outcomes following elective abdominal aortic aneurysm surgery: a cohort study

BACKGROUND

In 2009, the NHS evidence adoption center and National Institute for Health and Care Excellence (NICE) published a review of the use of endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAAs). They recommended the development of a risk-assessment tool to help identify AAA patients with greater or lesser risk of operative mortality and to contribute to mortality prediction.A low anaerobic threshold (AT), which is a reliable, objective measure of pre-operative cardiorespiratory fitness, as determined by pre-operative cardiopulmonary exercise testing (CPET) is associated with poor surgical outcomes for major abdominal surgery. We aimed to assess the impact of a CPET-based risk-stratification strategy upon perioperative mortality, length of stay and non-operative costs for elective (open and endovascular) infra-renal AAA patients.

METHODS

A retrospective cohort study was undertaken. Pre-operative CPET-based selection for elective surgical intervention was introduced in 2007. An anonymized cohort of 230 consecutive infra-renal AAA patients (2007 to 2011) was studied. A historical control group of 128 consecutive infra-renal AAA patients (2003 to 2007) was identified for comparison.Comparative analysis of demographic and outcome data for CPET-pass (AT ≥ 11 ml/kg/min), CPET-fail (AT < 11 ml/kg/min) and CPET-submaximal (no AT generated) subgroups with control subjects was performed. Primary outcomes included 30-day mortality, survival and length of stay (LOS); secondary outcomes were non-operative inpatient costs.

RESULTS

Of 230 subjects, 188 underwent CPET: CPET-pass n = 131, CPET-fail n = 35 and CPET-submaximal n = 22. When compared to the controls, CPET-pass patients exhibited reduced median total LOS (10 vs 13 days for open surgery, n = 74, P < 0.01 and 4 vs 6 days for EVAR, n = 29, P < 0.05), intensive therapy unit requirement (3 vs 4 days for open repair only, P < 0.001), non-operative costs (£5,387 vs £9,634 for open repair, P < 0.001) and perioperative mortality (2.7% vs 12.6% (odds ratio: 0.19) for open repair only, P < 0.05). CPET-stratified (open/endovascular) patients exhibited a mid-term survival benefit (P < 0.05).

CONCLUSION

In this retrospective cohort study, a pre-operative AT > 11 ml/kg/min was associated with reduced perioperative mortality (open cases only), LOS, survival and inpatient costs (open and endovascular repair) for elective infra-renal AAA surgery.