Pedal-Plantar Loop Techniques: Lessons From a Maestro

(Leipzig, Germany) January 31, 2020 -- Below-the-ankle revascularization and the pedal-plantar loop (PPL) technique was discussed by Marco Manzi, MD, Director of the Interventional Radiology Unit at Foot & Ankle Clinic of Policlinico Abano Terme (Padua, Italy).

Dr Manzi, who spoke by satellite from Abano Terme, has specialized in diabetic patients with critical limb ischemia (CLI) and wounds of the foot since 2001. “In our regional referral center, we treat more than 800 diabetic patients with CLI and wounds every year, following the multidisciplinary approach model,” he said. “That’s why we have been so deeply involved in extreme revascularization procedures.”

The PPL technique is such a procedure, said Dr Manzi, who spoke about its history in this afternoon’s session. “I will talk about the origins of this particular technique, especially about the father of the technique, Dr Lanfroi Graziani, who performed the first case in 2005,” he said. “I will describe the story of how the technique was developed, as well as the importance of the PPL or arch reconstruction, together with its limitations.”

As Dr Manzi underlined, recent articles stress the importance of focus on the pedal arch. One study found that patients with CLI who underwent pedal artery angioplasty (PAA) showed a higher rate of wound healing and shorter time to wound healing, especially in the moderate-risk population.¹

Another study reported on clinical implications (wound healing, time to healing, and survival) according to the pedal arch status at the end of an infrainguinal endovascular procedure.² It concluded that the pedal arch status has a positive impact on time to healing, limb salvage, and survival in diabetic patients with foot wounds undergoing infrainguinal endovascular revascularization. “The authors underline the improvement in patients’ wound healing whenever the patency of the arch is achieved,” explained Dr Manzi.

Importantly, there is another study where researchers retrospectively reviewed 1,915 limbs of 1,613 patients with symptomatic peripheral artery disease (PAD) who underwent angiography between September 2009 and November 2013.³ Here, they hypothesized a scenario where two different diseases might be present in PAD patients, big artery disease (BAD) and small artery disease (SAD), overlapping at the foot level. The study looked for prevalence and correlation with risk factors and CLI.

Interestingly, the researchers found SAD in 414 patients (25.2%), and that SAD was strongly and independently associated with CLI, diabetes, and dialysis. “Thus, SAD should be regarded as a leading actor in CLI,” they concluded.

And, here is where the PPL technique has its limitations, according to Dr Manzi. “The authors explain how it is not efficient in patients with disease of the small vessels in the forefoot [ie, SAD] because of the failure of the blood distribution system in the foot,” he said.

That’s why it’s critical to distinguish between patients, said Dr Manzi. “We must consider the difference in disease between the SAD and BAD patient when approaching revascularization procedures,” he explained. “For SAD patients, traditional endovascular treatment is of no value.”

Dr Manzi went on to describe a case that may help further understand the concept of treating SAD. “This is a patient where it has been possible to reconstruct the arch with a very bad clinical outcome,” he said.

Given the outcomes for such patients, Dr Manzi argued that considerable research is required today to explore alternative revascularization techniques. “Determining the value of deep (foot) vein arterialization (DVA) is actually one of the main research topics now,” he said. “It is an alternative treatment for SAD patients defined as no-option patients.”

DVA might be an option for CLI patients facing amputation. In patients with no outflow distal targets permitting bypass, DVA involves creating a connection between a proximal arterial inflow and a distal venous outflow in conjunction with disruption of the vein valves in the foot.⁴ This helps blood flow to reach the foot, resolve rest pain, and promotes healing of a chronic wound. DVA requires much more research, however, said Dr Manzi. “Of course, there is still little clinical data and absolutely no randomized, controlled trials,” he noted.

In the future, Dr Manzi would like to see more consistency in treatments: “The amount of calcium and the length of occlusions represents the main limitations for every below-the-knee, below-the-ankle and PPL procedure and really, it’s always a challenging situation,” he explained. “I would like to see the standardization of both the traditional procedure and DVA, too; only with standardization we can properly evaluate the value of techniques and clinical outcomes.”

Dr Manzi explained how standardization might be achieved. “To standardize a procedure means starting from the diagnostic angiogram,” he said. In other words, using the right projections to evaluate anatomical conditions and variations is crucial, as is using the proper amount and injection pressure of contrast medium or carbon dioxide. “Standard flowcharts in decision making processes and crossing strategies are important as well as the use of devices,” he explained.

In his conclusion, Dr Manzi emphasized the importance of focus on the pedal-plantar loop technique. “Whenever there is a clinical need for wound healing, we should try to achieve arch revascularization,” he said. “However, we must avoid it in SAD patients who probably need a different treatment, such as DVA.”

References

1. Nakama T, Watanabe N, Haraguchi T, et al. Clinical outcomes of pedal artery angioplasty for patients with ischemic wounds. J Am Coll Cardiol Intv. 2017;10(1):79–90.
2. Troisi N, Turini F, Chisci E, et al. Impact of pedal arch patency on tissue loss and time to healing in diabetic patients with foot wounds undergoing infrainguinal endovascular revascularization. Korean J Radiol. 2018;19(1):47–53.   
3. Ferraresi R, Mauri G, Losurdo F, et al. BAD transmission and SAD distribution: a new scenario for critical limb ischemia. J Cardiovasc Surg (Torino). 2018;59(5):655–664.
4. Ho VT, Gologorsky R, Chandra V. Open, percutaneous, and hybrid deep venous arterialisation technique for no-option foot salvage. J Vasc Surg. 2019.