Prophylactic Muscle Flaps in Vascular Surgery

Study Overview
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Brief Summary
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Previous studies have suggested that prophylactic muscle coverage in high-risk patients undergoing revascularization procedures through a groin incision have the potential to reduce rates of complications and re-operation. This is a prospective randomized control trial to test this hypothesis at the University of Wisconsin Hospitals and Clinics.

Detailed Description
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The incidence of graft infections after groin dissection for lower limb revascularization is estimated to be between 2 and 20%. Infection requiring re-operation and muscle flap coverage for salvage is estimated to be between 11 and 13%. Retrospective studies have endeavored to create risk calculators to better predict patients at high risk of need for muscle flap salvage. Fischer et al. suggest that in high-risk patients, prophylactic muscle flaps can reduce complications from 70% to 10%, rates of infection from 70% to 3% and wound breakdown from 48% to 5%. Cost-savings of around $400,000 per year with the use of prophylactic muscle flaps are estimated. Unfortunately, the retrospective nature of the Fischer et al. study, lack of standardization of patients receiving prophylactic muscle flaps, and use of the same cohort for the risk calculator as for the outcomes analysis all reduce the generalizability and reproducibility of these results. At the University of Wisconsin Hospitals and Clinics, muscle coverage is routinely used in cases of infection or lymph leak but is not systematically used in prophylactic settings. This is because it is generally left to surgeon preference-if they feel like a muscle flap is needed (for a variety of non-standardized anatomic/surgical or patient factors) then it is performed. Muscle coverage of vascular grafts in and of itself is not an experimental procedure and has been performed for decades. The goal of this study is to determine whether prophylactic muscle flaps in high-risk patients can a) reduce the rates of infection requiring re-operation, and b) reduce the significant morbidity associated with other non-operative complications. This will be the first prospective, randomized control trial to address this issue.

Official Title
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Prophylactic Muscle Flaps for the Prevention of Vascular Graft Infection After Groin Dissection

Conditions
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Vascular Graft Infection

Intervention / Treatment
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* Procedure: Prophylactic muscle flap


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Open lower extremity arterial revascularization Groin incision High-risk patients based on risk calculation Exclusion Criteria: Pregnant or breast-feeding Any person with diagnosis of an active groin infection preoperatively Incarcerated patients Unstable patients going directly to the OR for whom the study consent process would delay care, and those who cannot give informed consent to participate in the research study will be excluded If a surgeon feels that a patient should or should not receive a flap based on intra-operative or pre-operative characteristics, those patients will be excluded from the study Prior to a scheduled groin intervention case a prior authorization will be sent to the participant's insurance company. If the groin flap is denied, which would be highly unusual, then the participant would be excluded from the study.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Group 1: No flap<br>Participants will undergo the scheduled vascular surgery procedure without involvement of the plastic surgery team and use of muscle flaps for graft coverage. | |
| Experimental: Group 2: Prophylactic muscle flap<br>Participants will undergo the scheduled vascular surgery procedure and then a muscle flap will be used to cover the vascular graft by a plastic surgeon in the same setting. | Procedure: Prophylactic muscle flap<br>* A muscle flap refers to taking an expendable muscle with its vascular supply and moving it to a new area. In this case, the investigators will take a muscle from the leg or abdomen that is redundant (other muscles perform the same function) and moving it to cover vascular grafts to provide healthy tissue to prevent infection.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of Graft Infection Requiring Re-operation | Infection of the vascular graft as determined by clinical diagnosis which requires re-operation for washout or other indicated procedures | within 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of Infection Not Requiring Re-operation | Superficial infections treated with antibiotics alone or local wound cares | 1 year | 
| Incidence of Seroma | Fluid collection over the vascular graft | 1 year | 
| Incidence of Lymphocele | Collection of lymph fluid over vascular graft/operative field | 1 year | 
| Incidence of Wound Dehiscence | Incision breakdown that is managed with wound cares and does not require operative debridement | 1year | 
| Toronto Lower Extremity Salvage Score (TESS) at 3 months | This is a 32-item survey of activities commonly performed in daily life, each item scored on a 5 point likert scale where 1 is 'impossible to do' and 5 is 'not at all difficult'. The total possible range of scores is 32 to 160 where higher scores indicate less difficulty in performing tasks. Scores are often standardized to a 100-point scale to account for unanswered questions (referring to activities that they do not normally perform in everyday life). | 3 months | 
| Toronto Lower Extremity Salvage Score (TESS) at 6 months | This is a 32-item survey of activities commonly performed in daily life, each item scored on a 5 point likert scale where 1 is 'impossible to do' and 5 is 'not at all difficult'. The total possible range of scores is 32 to 160 where higher scores indicate less difficulty in performing tasks. Scores are often standardized to a 100-point scale to account for unanswered questions (referring to activities that they do not normally perform in everyday life). | 6 months | 
| Toronto Lower Extremity Salvage Score (TESS) at 9 months | This is a 32-item survey of activities commonly performed in daily life, each item scored on a 5 point likert scale where 1 is 'impossible to do' and 5 is 'not at all difficult'. The total possible range of scores is 32 to 160 where higher scores indicate less difficulty in performing tasks. Scores are often standardized to a 100-point scale to account for unanswered questions (referring to activities that they do not normally perform in everyday life). | 9 months | 
| Toronto Lower Extremity Salvage Score (TESS) at 12 months | This is a 32-item survey of activities commonly performed in daily life, each item scored on a 5 point likert scale where 1 is 'impossible to do' and 5 is 'not at all difficult'. The total possible range of scores is 32 to 160 where higher scores indicate less difficulty in performing tasks. Scores are often standardized to a 100-point scale to account for unanswered questions (referring to activities that they do not normally perform in everyday life). | 12 months | 
| Readmission rates | Rates of re-hospitalization after the index revascularization | 30- and 90-days | 
| Total cost of hospitalizations for index diagnosis |  | 1 year | 
| Number of clinic visits after index surgery |  | 1 year | 
| Death |  | 1 year |