Holding Pressure Case Prep - Fem Pop Byp...

Authors: 

Sebouh Bazikian - PGY1 at Emory School of Medicine Integrated Vascular Surgery Program

Miguel F. Manzure - vascular surgery attending the University of Southern California Keck School of Medicine involved in complex limb preservation

Core Resources:

• Rutherford Chapters: 107, 108, 109 (Includes further information on anatomy), 112

Additional Resources:

• Relevant trials
• • BEST CLI: https://pubmed.ncbi.nlm.nih.gov/36342173/
  • BASIL 2: https://pubmed.ncbi.nlm.nih.gov/37116524/
• Relevant Audible Bleeding episodes
• • Audible Bleeding Endovascular Basics: https://open.spotify.com/episode/7jDpkhGMauBslk8SBklCyB?si=75f0931773d24b91
  • Audible Bleeding eBook, CLTI Chapter: https://adam-mdmph.quarto.pub/vascular-surgery-exam-prep/clti.html
• Anything else useful
• • WIFI: https://pubmed.ncbi.nlm.nih.gov/24126108/
  • GLASS: https://pubmed.ncbi.nlm.nih.gov/31159978/
  • Monophasic, Biphasic, Triphasic Waveforms: https://pubmed.ncbi.nlm.nih.gov/32667274/

Underlying disease featured in episode - peripheral arterial disease

1. Pathophysiology/etiology
   1. narrowing of peripheral arteries caused by atherosclerotic plaques causing arterial insufficiency distal to the point of occlusion. This reduces oxygen supply to the muscles.
   2. When oxygen demand increases but cannot be met, it leads to an imbalance such as pain and poor wound healing. 
   3. Risks: smoking, diabetes, hypertension, dyslipidemia, and older age
   4. Equal prevalence in men and women, peak incidence age 60-80
   5. Coexists with CAD, DM, stroke, Afib, and renal disease
2. Patient Presentation
   1. 20-50% asymptomatic, rest can be intermittent claudication, rest pain, or tissue loss
   2. claudication=pain or discomfort felt in the legs due to a lack of blood flow, especially during physical activity. 
   3. CLTI=chronic limb threatening ischemia: rest pain lasting greater than 2 weeks or nonhealing ulcers and gangrene
   4. Physical exam: 
      1. decreased skin temperature, less hair on the legs, brittle nails, atrophied muscles, shiny skin, livedo reticularis.
      2. Absent or diminished pulses
      3. Buerger sign
3. Diagnosis
   1. Ankle brachial index: <0.9=PAD. <0.4=multilevel disease associated with tissue loss. >1.3 can mean vessel calcification
   2. Toe pressures, toe brachial indexes, and transcutaneous oxygen measurement (TcPO2) if vessels calcified
   3. Duplex ultrasound: affordable and effective, can assess both anatomy and blood flow
      1. Can also assess degree of stenosis based on ratios of systolic and diastolic velocity
   4. Angiography: gold standard. Invasive and risks of infection, hematoma, pseudoaneurysms, and contrast nephropathy.
   5. Staging:
      1. WIFI - Wound, Ischemia, and Foot Infection (see additional resources)
      2. GLASS: Global Limb Anatomy Staging System (see additional resources)
4. Treatment (Medical/Surgical)
   1. Lifestyle modification, smoking cessation, high-intensity statins, antiplatelet therapy, and management of other medial comorbidities like HTN and DM.
   2. Structured exercise program: 3 times weekly for 12 weeks
   3. Cilostazol: phosphodiesterase III inhibitor
   4. Endovascular and surgical revascularization
      1. Endovascular offer superior perioperative outcomes but lacks durability
      2. Surgical revascularization offer durability and less reinterventions, but more invasive

Indications for surgery:

• CLTI and lifestyle limiting claudication

Relevant anatomy:

• Femoral triangle
• • inguinal ligament superior, the medial border of the sartorius muscle laterally, and the medial border of the adductor longus on the medially
  • Contains neurovascular bundle (NAVEL)
• Adductor canal: bordered anteriorly by the sartorius, posteriorly by the adductor magnus and longus, and to the lateral side by the vastus medialis
• common femoral artery bifurcates into the profunda and the superficial femoral artery  (SFA). SFA courses through adductor canal and turns into popliteal artery in the popliteal fossa
• GSV: originates at the ankle, tracts anterior to medial malleolus and then ascending the medial side of lower leg. Upon reaching the knee, it curves behind the medial condyles of the femur and tibia, continuing alongside the medial aspect of the thigh. Its journey culminates at the saphenofemoral junction

Preoperative preparation:

1. Identifying inflow and outflow vessels, both should be free of significant disease
   1. preop CTA or angiogram
2. Picking a conduit
   1. Best patency=autogenous: reversed GSV most common, others are small saphenous vein, cephalic vein, etc
   2. Prosthetic: polytetrafluoroethylene (PTFE)
   3. Cryopreserved vein

Surgical steps:

1. Harvesting GSV (if GSV adequate as conduit)
   1. Dissected along its length, branches ligated, removed and reversed
   2. Can also be left insitu, so only proximal and distal aspects are mobilized, and valves are removed using valvulotome
   3. Should be at least 3mm in diameter and no significant disease (scarring, thickening)
2. Arterial exposure
   1. Common femoral artery: lies in the medial third segment between the ASIS and the pubic symphysis. Longitudinal or oblique incision directly over the femoral artery pulse if present. ligate venous and lymphatic tributaries in the soft tissue. Open fascia along the medial margin of the sartorius muscle, retracting the sartorius muscle laterally exposes the underlying femoral sheath. CFA is located within the femoral sheath.
   2. Profunda and superficial femoral artery: trace the anterior surface of the CFA to where it bifurcates. The origin of the profunda is typically lateral

1. Popliteal artery: medial longitudinal incision 1 to 2 cm behind the tibia's posterior border. Carefully to avoid GSV, dissect down to fascia to enter the popliteal fossa. The medial head of the gastrocnemius is retracted posteriorly, giving us a clear view of the popliteal fossa. popliteal artery is surrounded by paired popliteal veins with smaller bridging veins

1. Tunneling and anastomosis
   1. Can be done anatomically or subcutaneously
   2. Must be careful not to twist the conduit
      1. Can do proximal anastomosis to pressurize vein prior to tunneling to minimize chance of twisting
   3. Clamp the vessels and heparinize
   4. Arteriotomy on femoral artery and anastomosis, same with popliteal artery distally
2. Closure and ensure patency
   1. Optional completion angiogram

Postoperative care:

• Anticoagulation and/or antiplatelet therapy
• Monitor graft patency once discharged with duplex/ABI

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