Socioeconomic Disadvantage is a Leading Variable in Risk Score for Major Amputation Following Emergent Infra-Inguinal Arterial Bypass Surgery.

OBJECTIVE: The purpose of this study is to identify patients at particularly high risk for major amputation following emergent infra-inguinal bypass to help tailor postoperative and long-term patient management. METHODS: In the Vascular Quality Initiative, we identified 2126 patients who underwent emergent infra-inguinal artery bypass. Two primary outcomes were investigated : major ipsilateral amputation above the ankle level during index hospitalization and major amputation above the ankle at any time after emergent infra-inguinal bypass surgery (perioperative and post discharge combined). Binary logistic regression analysis was performed for each outcome utilizing variables which achieved a univariable P value < .10. We then determined which variables have a multivariable association for the outcomes as defined by a regression P value of .05 or less. A risk score was then created for the outcome of amputation after emergent infra-inguinal bypass using weighted beta-coefficient. Variables with a multivariable P-value < .05 were included in the risks score and weighted based on their respective regression beta-coefficient in a point scale. RESULTS: Overall, 17.1% (368/2126) of patients experienced major amputation at some point in follow up after emergent infra-inguinal artery bypass. Mean follow up duration on the amputation variable was 261 days with end point being time of amputation or time of last follow up data on the amputation variable. Variables with a significant multivariable association (P<.05) with major amputation at any point after emergent infra-inguinal arterial bypass were : home status in top 10% (most deprived) of area deprivation index; prior infra-inguinal ipsilateral arterial bypass; prior ipsilateral endovascular arterial intervention; prosthetic bypass conduit; postoperative skin/soft tissue infection; and postoperative need to revise or thrombectomize bypass. Pertinent negatives on multivariable analysis included all baseline co-morbidities, insurance status, race, and gender. There is steep progression in amputation rate ranging from 5% at scores of 0 and 1 to over 60% for scores in excess of 10. AUC analysis revealed a value of .706. CONCLUSIONS: Patients living in the most disadvantaged socioeconomic neighborhoods have an increased risk of amputation following emergent infra-inguinal arterial bypass independent of baseline co-morbidities and perioperative events. Baseline co-morbidities are not impactful regarding amputation rates after emergent infra-inguinal bypass surgery. The need for bypass revision or thrombectomy during index hospitalization is the most impactful factor towards amputation after emergency bypass. A risk score with quality accuracy has been developed to help identify patients at particularly high likelihood of limb loss which may aid in counseling regarding heightened vigilance in postoperative and long term follow up care.

Risk score for one-year mortality following emergent infra-inguinal bypass.

OBJECTIVE: The purpose of this study is to identify variables that place patients at higher risk for mortality following emergent infra-inguinal bypass. Further, this study will create a risk score for mortality following emergent infra-inguinal bypass to help tailor postoperative and long-term patient management. METHODS: In the Vascular Quality Initiative, we identified 2126 patients who underwent emergent infra-inguinal artery bypass. Two primary outcomes were investigated: 30 day mortality following emergent infra-inguinal bypass; and 1-year mortality following emergent infra-inguinal bypass. The first step in analysis was univariable analysis for each outcome with χ2 analysis for categorical variables and Student t-test for comparison of means of ordinal variables. Next, binary logistic regression analysis was performed for each outcome utilizing variables that achieved a univariable P value ≤ .10. Factors with a multivariable P value ≤ .05 were included in the risk score, and points were weighted and assigned based on the respective regression beta-coefficient in the multivariable regression. RESULTS: Variables with a significant multivariable association (P < .05) with 1-year mortality were: increasing age; body mass index less than 20 kg/m2; coronary artery disease; active hemodialysis at time of presentation; anemia at admission; prosthetic conduit for emergent bypass; postoperative myocardial infarction; postoperative acute renal insufficiency; perioperative stroke; baseline non-ambulatory status; new onset hemodialysis requirement perioperatively; need for bypass revision or thrombectomy during index admission; lack of statin prescription at discharge; lack of antiplatelet medication at discharge; and, lack of anticoagulation at time of hospital discharge. Pertinent negatives included all sociodemographic variables including rural living status, insurance status, and Area Deprivation Index home area. The risk score achieved an area under the curve of 0.820, and regression analysis of the risk score achieved an overall accuracy of 87.9% with 97.7% accuracy in predicting survival, indicating the model performs better in determining which patients will survive rather than precisely determining 1-year mortality. CONCLUSIONS: Discharge medications are the primary modifiable variable impacting survival after emergent infra-inguinal bypass surgery. In the absence of contraindication, all these patients should be discharged on antiplatelet, statin, and anticoagulant medications after emergent infra-inguinal bypass as they significantly enhance survival. Social determinants of health do not impact survival among patients treated with emergent infra-inguinal bypass at Vascular Quality Initiative centers. A risk score for mortality at 1 year after emergent infra-inguinal bypass has been created that has excellent accuracy.