As the number of patients suffering from amputations due to peripheral vascular disease continues to increase, deep vein arterialization (DVA) offers an alternative for no-option patients.
What is DVA?
An aging population coupled with an uptick in diabetes and renal failure has increased the prevalence of peripheral vascular disease, especially the prevalence of small artery disease (SAD). Many of these SAD patients have limited vascular reconstruction options, primarily due to the lack of outflow vessels necessary for successful open or endovascular reconstruction.
Data shows that the probability of healing a wound without vascular reconstruction is about 20% with wound care treatment alone, and amputation, whether above or below the knee, is associated with increased mortality for patients.
DVA involves creating a connection between an proximal arterial inflow and a distal venous outflow in conjunction with disruption of the vein valves in the foot. This technique allows blood flow to reach the foot, resulting in the salvaging of the limb so amputation is not needed.
DVA is a hot topic, but it isn’t new. This process was first documented in 1912 by Dr. Halstead, advanced by Dr. Lengua in Peru, and recently brought into the endovascular arena by several pioneers in Vascular Surgery.
Patient Selection for DVA
When beginning this treatment, patient selection needs to be considered conservatively.
The ideal patient has a wound limited to the forefoot, although it is possible to treat superficial heal wounds.
The wound should also be stable for a minimum of one month, because that’s the average time necessary for remodeling of the blood vessels that will lead to increased tissue perfusion. This is monitored in my practice by TcPO2.
In patients who have a saphenous vein of adequate caliber, which is continuous with the marginal vein and the venous arch, the first treatment option is the "Lengua" technique.
In those patients who do not have this option due to anatomical limitations, a "Limflow" style endovascular option should be considered.
For an endovascular approach, an ultrasound evaluation of the plantar veins and venous arch should be performed prior to intervention.
To be a candidate for either of these two procedures, the patient must have a minimum cardiac ejection rate of 35% and no major comorbidities that would have prevented a traditional intervention.
Once the procedure is performed, I keep the patient on antiplatelet medication and heparin. In the immediate postoperative period, we measure the flow volumes through the arterialization at the ankle. We consider a flow rate between 200-300 mL/min adequate.
About 3-5 days after the initial procedure we perform an additional angiogram in which we evaluate the evolution of the arterial/venous flow of the foot and perform additional valve lysis and/or coiling.
Procedure: They Hybrid “Lengua” Technique
This technique usually entails an in situ anastomosis of the greater saphenous vein at the level of the proximal medial calf usually to the popliteal artery or distal superficial femoral artery, followed by percutaneous access of the medial marginal vein and placement of a 5 French sheath through which a valvulotome is inserted. The entire vein undergoes valve lysis through this approach.
Three to 5 days after the initial procedure we performed an additional angiogram in which we open venous valves in the foot usually in the distal medial marginal vein and embolize high flow vessels that are stealing flow from the affected area of the foot. At this point, if the initial flow is greater than 500 mL/min, having a higher risk of "Steal Syndrome," the venous vessel that drains fastest should be embolized, re-evaluating the flow intraoperatively after each embolization.
A good angiographic rule of thumb is that flow through the arterialization circuit should mimic the flow velocity through the native vessels. At this stage, it is important to keep several details in mind:
- Arterialized venous vessels tend to spasm after manipulation with guidewires and catheters. Therefore, those interventions that, in the opinion of the interventionalist, have the greatest benefit should be performed first.
- Opening flow to the venous arch of the foot is essential for an acceptable result, thus this should be done first.
- When embolizing, the coil should not be placed in the dorsal aspect of the foot, but at the level of the ankle or above, given the risk of forming a new foot ulcer.
Once the interventionalist is satisfied with the angiographic results and with the arterialization flow volumes, the patient can be discharged and followed up in the clinic.
Once the interventionalist is satisfied with the angiographic results and arterialization flow, the patient can be discharged.
In my practice we do a baseline TcP02 measurement prior to discharge and then every two weeks thereafter. We expect to see a rise in the TcP02 value between 4-6 weeks after the initial procedure.
A TcP02 value of 40 mmHg is predictive of healing. Once we see a rise in values, we proceed to do an angiography to re-evaluate the flow and if necessary localize it to the affected area through selective embolizations, taking into consideration the flow of the arterialization.
Once this last intervention has been performed we proceed to do a guillotine amputation usually with a biological matrix covering and a negative pressure dressing.
Although this procedure promises many benefits for patients, DVA can have a steep learning curve, and caution must be exercised in patient selection. Once you’ve mastered those key hurdles, DVA presents a reliable alternative for those patients who do not have a traditional revascularization option.