Risk factors and outcomes for infrainguinal bypass in the Regina Qu'Appelle Health Region

1. Risk factors and outcomes for infrainguinal bypass in the Regina Qu'Appelle Health Region Jonathan Misskey, David Kopriva MDCM FRCSC, Donald McCarville MD FRCSC

2. Peripheral vascular disease

3. Peripheral vascular disease and infrainguinal bypass Infrainguinal bypass: Creation of an alternative conduit for blood flow around an obstruction to the lower extremities using autologous vein or a synthetic graft (e.g. polytetrafluoroethylene)

4. Study Rationale • Outcomes for carotid endarterectomies and abdominal aortic aneurysm surgeries are regularly recorded and analyzed for quality control purposes • No such data exists for infrainguinal bypass • Through analysis of hospital records of patients admitted for infrainguinal bypass, this study aims to identify pertinent risk factors for the implementation of targeted improvements in perioperative patient care

5. Methods Data Collection • Retrospective medical chart review of all cases of infrainguinal bypass for the last seven years (April 1 2002 – March 30 2009) • Data was collected on 116 patient variables (demographics, comorbidities, intraoperative factors) • Seven outcomes (postoperative infection, graft failure, limb loss, renal failure, stroke, myocardial infarction and death) were recorded • Cases of infrainguinal surgery via suture repair of pseudoaneurysms, aorto/axillary-distal bypasses for aortoiliac atherosclerosis or abdominal aortic aneurysm were excluded Data Analysis • Data were analyzed using the Pearson chi-squared test for categorical variables and when applicable the student’s T test for continuous variables. • Multivariate analysis was used to determine independent associations between adverse events and patient/procedural risk factors • Multivariate analysis was performed using multiple logistic regression with SPSS v17.0 • All data with P < 0.1 in univariate analysis were included in multivariate analysis

6. Results • Data was collected on a total of 680 lower limb bypasses • 173 were femoral inflow procedures - (i.e. axillofemoral, aortofemoral, cross-femoral) and will be entered into a lower limb bypass database but were excluded from this study • Femoral inflow procedures constitute a different operation and cannot be reliably compared with infrainguinal bypass statistically • 507 infrainguinal bypasses were included in this study

7. Postoperative wound infections 54 (10.6%)

8. Graft failure 58 (11.4%) Mills valvulotome (n = 267) had a lower graft failure rate than the LeMaitre valvulotome (n = 40) with limited saphenous exposure (P < 0.001)

9. Limb loss 44 (7.5%)

10. Renal failure 5 (1.0%)

11. Stroke 9 (1.8%)

12. Myocardial infarction 22 (4.3%)

13. Mortality 15 (3.0%)

14. Conclusions and clinical implications • Outcomes are consistent with national and international benchmarks • BMI > 40, history of heart failure and orthopedic mobility impairment are independently associated with >1 adverse events • LeMaitre valvulotome – minimally invasive method found to have statistically higher failure rate than open method • Revision of method required to achieve results comparable to Mills valvulotome • Minimally invasive techniques would have a large benefit on the identified at risk groups • Results suggest risk factor management important for maximizing good postoperative outcomes (e.g. importance of postoperative mobilization in those with mobility impairment)

15. Acknowledgements • Kim Fichter and Medical Records • University of Saskatchewan College of Medicine Dean’s Office

16. Questions?