Overview
Definition:
Tibial-peroneal trunk bypass is a surgical procedure to revascularize the distal lower extremity when the superficial femoral artery (SFA) and popliteal artery are occluded or severely diseased, and the tibial or peroneal arteries serve as the distal target
This typically involves bypassing the blocked segment using an autologous vein or prosthetic graft, originating from the common femoral artery or a more proximal source, and tunneling it down to a patent segment of one of the tibial or peroneal arteries.
Epidemiology:
Peripheral arterial disease (PAD) affects millions worldwide, with critical limb ischemia (CLI) representing the most severe form
Tibial-peroneal trunk bypass is reserved for patients with CLI who have no suitable superficial femoral artery or popliteal artery target for more distal bypass, making it a procedure for a subset of advanced PAD patients
Risk factors include advanced age, diabetes mellitus, smoking, hypertension, hyperlipidemia, and chronic kidney disease.
Clinical Significance:
This bypass is crucial for limb salvage in patients with CLI who are at high risk of amputation
Successful revascularization can alleviate ischemic pain, promote wound healing, and restore walking capacity, significantly improving the patient's quality of life and reducing morbidity and mortality associated with major amputation.
Indications
Indications For Bypass:
Severe limb-threatening ischemia (Rutherford category 4, 5, or 6)
Failed previous revascularization attempts
Absence of suitable distal targets in the SFA or popliteal artery
Occlusive disease involving the trifurcation vessels requiring distal bypass to a patent tibial or peroneal artery.
Patient Selection:
Careful patient selection is paramount, considering comorbidities, functional status, and life expectancy
Preoperative assessment of pedal pulses, ankle-brachial index (ABI), toe-brachial index (TBI), and transcutaneous oxygen tension (TcPO2) is essential
Angiography is mandatory to define the extent of disease and identify suitable inflow and outflow vessels.
Contraindications:
Uncorrectable coagulopathy
Severe systemic illness precluding surgery
Absence of a suitable inflow artery
Complete occlusion of all tibial and peroneal arteries distally with no usable outflow segment
Patient refusal or inability to tolerate major surgery.
Preoperative Preparation
Medical Optimization:
Management of comorbidities such as diabetes, hypertension, and heart failure
Smoking cessation counseling and support
Optimization of renal function
Antithrombotic therapy initiation.
Imaging And Planning:
Detailed arteriography of the entire aortoiliac and femoropopliteal segments, including the tibial and peroneal arteries, is crucial for planning the bypass route and identifying the optimal target vessel
Non-invasive vascular studies like duplex ultrasonography aid in assessing inflow and outflow vessel quality.
Graft Selection:
Autologous great saphenous vein (GSV) is the preferred conduit for tibial-peroneal trunk bypass due to superior patency rates
If GSV is unavailable or inadequate, alternative options include reversed GSV, other homologous veins, or prosthetic grafts (e.g., expanded polytetrafluoroethylene - ePTFE), though prosthetic grafts generally have poorer outcomes in this distal position.
Anesthesia Considerations:
General anesthesia or regional anesthesia (spinal/epidural) may be used
Monitored anesthesia care (MAC) can also be an option for select patients
Intraoperative monitoring of hemodynamic status, urine output, and systemic temperature is essential.
Procedure Steps
Inflow Site Preparation:
An incision is made in the groin to expose the common femoral artery (CFA) for anastomosis
The CFA is dissected, and heparin is administered
The CFA is cannulated and controlled with vessel loops or clamps.
Outflow Site Dissection:
The planned distal target artery (e.g., anterior tibial, posterior tibial, or peroneal artery) is identified and dissected, usually through a fasciotomy or skin incision along the course of the vessel
The vessel is carefully isolated from surrounding tissues, taking care to preserve its adventitia.
Graft Placement And Anastomosis:
The chosen graft (e.g., reversed GSV) is tunneled subcutaneously or intermuscularly from the inflow to the outflow site
The proximal anastomosis is typically an end-to-side anastomosis to the CFA
The distal anastomosis is performed as an end-to-side anastomosis to the selected tibial or peroneal artery
Careful attention is paid to achieving tension-free, leak-proof anastomoses using appropriate sutures (e.g., 5-0 or 6-0 polypropylene).
Graft Checking And Completion:
After completing both anastomoses, the vascular clamps are sequentially released, and the graft is flushed to remove any thrombus
The patency of the bypass is assessed by Doppler ultrasound and visual inspection for pulsatility and filling
Hemostasis is achieved, and incisions are closed.
Postoperative Care
Monitoring And Care:
Close monitoring of the graft for patency (e.g., Doppler ultrasound, visual inspection of limb perfusion)
Strict fluid management and maintenance of adequate blood pressure
Pain management
Early mobilization as tolerated.
Antithrombotic Therapy:
Aggressive antithrombotic therapy is crucial for graft patency
This typically includes aspirin (e.g., 75-150 mg daily) and clopidogrel (e.g., 75 mg daily) for a specified period, often lifelong
Low-molecular-weight heparin (LMWH) may be used in the immediate postoperative period
Warfarin may be considered in specific high-risk scenarios.
Wound Care And Limb Perfusion:
Meticulous wound care to prevent infection
Regular assessment of pedal pulses, capillary refill, skin temperature, and color to ensure adequate limb perfusion
Management of any flap dehiscence or wound complications.
Comorbidity Management:
Continued management of diabetes, hypertension, hyperlipidemia, and other comorbidities to optimize overall patient health and promote long-term graft patency.
Complications
Early Complications:
Graft occlusion (thrombosis) due to technical errors, hypotension, or hypercoagulability
Bleeding from anastomoses
Infection of the graft or wound
Limb compartment syndrome
Distal embolization
Neurological deficits.
Late Complications:
Graft stenosis or occlusion due to intimal hyperplasia or atherosclerotic progression
Pseudoaneurysm formation at anastomoses
Chronic graft infection
Progression of distal atherosclerotic disease
Amputation if bypass fails or is not feasible.
Prevention Strategies:
Meticulous surgical technique with appropriate graft selection and tension-free anastomoses
Aggressive perioperative and long-term antithrombotic therapy
Strict control of cardiovascular risk factors
Careful postoperative monitoring for early signs of graft dysfunction or limb ischemia
Prompt intervention for any detected graft abnormalities.
Prognosis
Factors Affecting Prognosis:
Graft patency rates are generally lower for tibial-peroneal trunk bypass compared to more proximal bypasses, especially when using prosthetic material
Factors influencing success include the quality of the outflow vessel, patient's comorbidities, adequacy of inflow, and compliance with medical therapy
Autologous vein grafts have better long-term patency.
Outcomes:
Successful revascularization can lead to limb salvage in 70-80% of patients at 1-2 years
Amputation-free survival is a key outcome measure
Pain relief and wound healing are also critical indicators of success
Patients with successful bypass may experience improvement in walking distance and quality of life.
Follow Up:
Regular lifelong follow-up is essential, including clinical assessment and non-invasive vascular imaging (e.g., duplex ultrasound) to monitor graft patency and detect early signs of stenosis or occlusion
This allows for timely intervention to preserve graft function and prevent limb loss.
Key Points
Exam Focus:
Tibial-peroneal trunk bypass is indicated for critical limb ischemia (CLI) when no suitable SFA or popliteal target is available
Autologous saphenous vein is the conduit of choice
Complications include graft occlusion and infection
Lifelong antithrombotic therapy and regular follow-up are crucial.
Clinical Pearls:
Thorough arteriography is mandatory to identify the optimal distal target vessel
Careful dissection to preserve adventitia of the target artery can improve anastomotic healing
Consider fasciotomy for adequate exposure of distal vessels and to relieve potential compartment syndrome post-reperfusion.
Common Mistakes:
Failure to adequately assess inflow and outflow vessels
Inadequate antithrombotic therapy postoperatively
Not performing adequate surveillance for graft failure
Using prosthetic grafts when autologous vein is available for distal bypass.