by Paul van Bemmelen, MD, PhD, FACS
Silly new therapies that gained credibility
For most people, their beliefs are not subject to change unless they see something for themselves, and even then, initially, they cannot believe their eyes. This first experience is hard to obtain when a skeptic is not willing to try the new therapy. During a recent workshop on negative pressure wound healing, a participant exclaimed (as if he saw the emperor naked in his new clothes): “This can’t work! It is just an ordinary polyurethane foam sponge!” He admittedly had never seen a vacuum assisted wound closure in his life. I remember thinking similar thoughts, albeit 17 years earlier.
Recently, I have witnessed a similar pattern, whereby a host of non-believers are speaking out against medical devices before they’ve even had a chance to really study its effects. Arterial intermittent pneumatic compression (IPC) therapy is a prime example. Arterial IPC, with the ArtAssist® device, consists of positive pressure using ordinary compressed air, a raw material that is abundant on this planet. In the 1996 yearbook of Vascular Surgery, the concept of arterial IPC was deemed silly, but by the year 2000 the same editor’s attitude had changed, in his own words, from “ridiculous” to “maybe.” Since then, a lot has changed.
In this article, we take a closer look at the recently studied therapeutic effects of IPC for arterial patients with non-reconstructable critical limb ischemia (CLI) who may be facing major amputations. The technological breakthrough of duplex ultrasound made it possible for the author to observe the brief post-compression arterial flow augmentation that occurs upon the emptying of leg and foot veins in real-time. This led to the bio-engineering of an IPC device specifically timed to generate increased arterial flow: the ArtAssist® device.
Several physiological studies using laser-Doppler were performed on normal volunteers and on arterial insufficiency patients to document that an increase in skin-perfusion occurred during/after the time of increased popliteal artery flow. A nice “model” to study the effect of long-term application in humans was stable intermittent claudication. At least four different prospective, randomized studies using the ArtAssist® device were published by independent authors in UK, USA, Italy, and Taiwan. These demonstrated an increase in pain-free walking and absolute claudication distance (ACD) due to collateral formation with the ArtAssist® device, which persisted for at least one year.
As promising as intermittent claudication trials are with IPC, patients are still presented with an abundance of treatment options. During the decade in which most of these studies were performed, the standard medical therapy changed from pentoxifyllin to cilostazol, which proved to be fairly effective. At the same time, more liberal application of endovascular treatment and stents for superficial femoral artery (SFA) occlusion became popular. Except for patients with side-effects from cilostazol or failure of stent therapy, the clinical problem of intermittent claudication has not necessitated widespread use of arterial IPC.
Arterial compression treatment: confronting impending limb-loss
The situation is different with regard to critical limb ischemia (CLI) and impending limb loss. Collectively, we perform major amputations at an alarming rate of about 300 per day in the U.S. alone. When the first issues of the Journal of Vascular Surgery were published (1984), vascular patients were more likely to smoke and less likely to have diabetes and obesity than at the present time. Highly effective and durable, open inflow procedures have now been outnumbered by very distal bypass surgeries with a less favorable risk-benefit ratio. Recognition of the short expected life span of the patients added to more frequent use of tibial angioplasty, which is now becoming more prevalent than open distal bypass in many countries.
At the current time, however, the vascular population is aging; many outflow procedures are not very durable and amputation rates still leave room for improvement. Local utilization of costly technology, such as endovascular atherectomy, new medicated balloons, and new stents, may be affected by reimbursement and national health systems. Because of this, it is interesting to note the different countries wherein recent clinical studies with IPC for CLI have been performed. In contrast to the United States, such countries do not follow a fee-for-service system. The following studies were done without knowledge or support from the industry by centers who obtained their own IPC devices. These studies can be considered to be objective.
Taiwan: In 2012, Chang et al. studied 31 patients with infra-popliteal diffuse or multiple segmental lesions and used the ArtAssist® device. Self-assessment of quality of life (QOL) was evaluated with the SF-36 scoring system and was translated in Taiwanese. The study found significant improvements in QOL and TcPO2 in the IPC group.
Ireland: Sultan et al. treated 171 patients with the ArtAssist® device. The first longitudinal comparison study by this group (2008) consisted of a prospective parallel-group and demonstrated increased limb salvage and reduced length of hospital stay in patients with non-reconstructable vessels treated with the ArtAssist® device. Major cost-savings when IPC was compared to primary amputation were calculated to be about $23,000 per patient. The second paper (2011) had angiographical documentation of severe outflow disease, demonstrated significant increase in toe pressures after three months of IPC, and found that 94% of patients reverted back to Rutherford category 3.
Canada: Louridas et al. randomized 84 patients with 99 critically ischemic limbs to either the ArtAssist® device or placebo device. In the initial pilot study, 33 legs had a significant increase in toe pressure before and after and were reported in 2002. The larger series showed a significant reduction in limb loss in the IPC-treated group compared to placebo.
As is also the case with negative pressure wound therapy devices, arterial IPC “knock-off” devices have not demonstrated clinical efficacy comparable to the ArtAssist® device. One key distinction that the ArtAssist® device makes is the employment of multiple working-mechanisms at the cellular level that are now being elucidated—the release of nitric oxide is directly related to shear-stress forces that are generated during rapid pressure rises and falls over time. ArtAssist® devices accomplish this by storing compressed air in a high-pressure tank, which is constantly being filled as opposed to modified venous IPC pumps, which consist of small air pumps that slowly fill tiny bladders placed around the leg. The indications for use of IPC are becoming more clearly defined and include so called “no option” arterial disease.
The role of the vascular specialist
What is “non-reconstructable” arterial disease in the year 2014? This question no longer has a simple answer based on arteriographic images. Even without named distal vessels in the foot, new endovascular tools for the recanalization of small tibial and pedal vessels appear daily. Rather, the concept of “non-reconstructable” is a multi-factorial Gestalt that takes shape after multiple procedures have failed, or if the patient has undergone life-altering procedures, such as a heart transplant and/or moderate renal failure. For this reason, these decisions have to be made together with a vascular specialist who is well versed in all therapeutic options and not just based on patient preference, etc. The figure illustrates one arteriogram (lateral foot projection) that would have been called “non-reconstructable” in the past, but now tends to be euphemistically described as “challenging.”
Vascular specialists are bound to encounter “challenging” cases in their practices, yet I consider myself armed with the option of arterial IPC. The results I witness consistently with this therapy reach beyond scientific figures in black-and-white, to otherwise untreatable patients who have regained their vitality and dignity. The time has come for more comprehensive vascular care in light of new and effective biotechnology.
ArtAssist® devices are available with a doctors’ prescription in the U.S. as a three-month rental (total cost is $1,200) for home treatment (recommended three, one-hour sessions spread out during the day) and can be readily available in most cases. Medicare reimbursement is currently available in certain situations. The contraindications are recent ipsi-lateral deep vein thrombosis (DVT) and uncontrolled foot infection with sepsis. Prescriptions can be directly faxed to ACI Medical, LLC, which will ship devices directly to the patient’s home. Reference details on the above mentioned studies and further information are listed on the website: www.ACIMedical.com.
Paul van Bemmelen is professor of surgery and practices vascular and endovascular surgery in Philadelphia, PA. He used the first ArtAssist® device prototypes on patients.