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Compressing Ischemic Limbs and Why It’s Beneficial

To download a printable PDF of this article, click here:  Compressing Ischemic Limbs and Why It’s Beneficial

The Misconception

Is it true that arterial occlusive disease is an absolute contraindication for intermittent pneumatic compression (IPC)?

The Answer

Not at all!

Unfortunately, many medical professionals are under the impression that applying even a small external pressure to an ischemic limb with reduced distal arterial pressures may serve to reduce or completely stop the already-compromised blood flow. This article presents strong evidence that, contrary to popular belief, IPC can bring life-changing benefits to those who cannot undergo revascularization.

History

Part of the reason this dogma exists is because, for many who consider it, applying IPC to ischemic limbs seems counterintuitive and likely dangerous. Also contributing to this myth are the literature reviews written by investigators as far back as 1934 who showed a poor understanding of the physiological mechanisms. Though these measured acute effects of compression on increased blood flow in ischemic limbs and relief of symptoms, the assessments made about IPC therapy were muddled due to the use of a great variety of compression schemes and devices. This lack of clarity resulted in literature that only served to feed misgivings about IPC as a treatment modality.

Physiological & Optimization Studies | ACI Medicalarteriovenous pressure gradient

To demystify the true value of IPC, our goal was to determine the physiological mechanisms of action, to optimize IPC design for maximal acute effect, and to determine if there is a clinical benefit to patients with lower extremity ischemic disease.

We started with physiological studies1 with compression applied to the dependent limb, which showed these acute mechanisms:

  • Increased arterial-venous pressure gradient
  • Reduced peripheral resistance
  • Abolition of the veno-arteriolar reflex

Further studies2 concerned optimization:

  • Pressure:  at least 120 mmHg
    This high pressure is required to empty the veins in the dependent limb, which temporarily reduces venous pressure to near zero and increases the arterial-to-venous pressure gradient and therefore, flow. Reducing venous pressure also serves to temporarily abolish the veno-arteriolar reflex, which allows for arteriolar dilation.
  • Timing:  3 second pulses followed by 17 seconds of low pressure
    An essential requirement for an arterial pump is the ability to quickly reach inflation and deflation pressures with rise times of 0.25 to 0.30 seconds and fall times under 0.5 seconds.  This rapid squeeze and release creates blood velocities that apply shear stress to the endothelium which releases nitric oxide and further supports the large acute vasodilatory effect in the arterioles.
  • Compressed tissues:  foot, ankle and calf regions
    In order to maximize blood flow through the major arteries and to the toes where ischemic disease often presents, we found that a circumferential foot bladder including the ankle should be compressed first, followed one second later by compression of the calf with a relatively large asymmetrical bladder.

Randomized Controlled Trials | ACI Medical

Intermittent Claudication

Once the arterial IPC device was optimized, three randomized controlled trials3 were performed on patients with intermittent claudication. Not only did these trials yield significantly increased walking distances of two to three times, but also sustained “permanent” improvements begged the question, “What long term mechanisms might be at work?”

Limb Salvage due to Arteriogenesis

Further studies4 showed that arteriogenesis (the opening of collaterals) was responsible for improved ABI’s, PVR’s, toe pressures and popliteal flow. A recently published study from 20105 reported a 94% limb salvage rate at 3.5 years in patients who were unable to undergo revascularization procedures.

Arterial Assist Device, NOT Lymphedema Pump

ArtAssist Arterial Assist Device

ArtAssist®…The Arterial Assist Device®

Today, it is widely-known that IPC devices are designed for prophylaxis against deep vein thrombosis (DVT) and for treatment of lymphedema. However, the understanding behind these devices does not coincide with our exploration of IPC to treat severe forms of arterial disease. Lymphedema and DVT devices do not apply enough pressure to the dependent limb to adequately empty the veins, nor do they apply and release pressure rapidly enough to stimulate release of nitric oxide (NO). While such devices will not significantly improve blood flow in the ischemic limb, it is difficult to say whether they would be harmful without further study.

References in this Publication

  1. Effect of intermittent pneumatic foot compression on popliteal artery haemodynamics. Delis, K.T.; Labropoulos, N.; Nicolaides, A.N.; Glenville, B.; and Stansby, G. Imperial College School of Medicine, Academic Vascular Surgery, St. Mary’s Hospital, London, UK. Eur J Vasc Surg, p. 270-277, vol. 19, no. 3, March 2000.
  2. Optimum intermittent pneumatic compression stimulus for lower-limb venous emptying. Delis, K.T.; Azizi, A.A.; Stevens, R.J.G.; Wolfe, J.H.N. and Nicolaides, A.N. Irvine Lab for Cardiovascular Investigation and Research Academic Vascular Surgery, Imperial College School of Medicine, St. Mary’s Hospital, London, UK. Eur J Vasc Endovasc Surg 19, 261-269 (2000).
  3. Improvement in walking ability, ankle pressure indices and quality of life in vascular claudication using intermittent pneumatic foot and calf compression:  a randomized controlled trial. Delis, K.T.; Nicolaides, A.N.; Cheshire, N.J.W.; Wolfe, J.H.N. St. Mary’s Hospital, London, UK. British Journal of Surgery December 2002; Volume 88, Issue 4:605-606.
  4. Angiographic improvement after rapid intermittent compression treatment (ArtAssist®) for small vessel obstruction. Van Bemmelen, P.; Char, D.; Giron, F.; and Ricotta, J.J. Dept. of Surgery, Div. of Vascular Surgery, State University of New York at Stony Brook, NY. Ann Vasc Surg 2003; 17:224-228.
  5. Sequential compression biomechanical device in patients with critical limb ischemia and nonreconstructable peripheral vascular disease. Sultan, S.; Hamada, N.; Soylu, E.; Fahy, A.; Hynes, N. and Tawfick, W. Department of Vascular and Endovascular Surgery, University College Hospital, Galway, Journal of Vascular Surgery 2011; 54:440-447.
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Building collateral arteries with ArtAssist® device compression therapy

Arteriogenesis:  the key to success

For patients who are surgical candidates, the solution to their arterial obstruction comes as quickly as a surgeon can work.

English: podiatric surgery

English: podiatric surgery (Photo credit: Wikipedia)

However, this means that non-operable patients and their doctors are left to find alternative solutions to improving lower extremity circulation. Drugs and lifestyle changes may work as long as the regimen is maintained, but these may still present problems according to each patient’s case.

Patients who use the ArtAssist® device every day for at least 90 days have developed permanent collateral arteries as a result of therapy.

This solution may be ideal for doctors with patients who have otherwise run out of options. With proven efficacy and consistently high success rates, those with severe PAD get another chance to rebuild and strengthen the collateral arteries in their lower extremities.

The theory

When developers optimized the ArtAssist® device to maximize blood flow to the lower extremities, they realized that, even after having stopped therapy with the device, patients kept their improved circulation. “Why is this?” they asked.

After some educated guessing, Paul van Bemmelen, MD, PhD of Temple University began looking into the hypothesis more closely. This publication (Fig. 1) is the first to have documented a threatened limb before and after four months of ArtAssist® device therapy.

The Rabbit study

In 2007, Dr. van Bemmelen performed another study, this time with a rabbit model. He and his team were able to confirm that intermittent pneumatic compression on the experimental limbs increased the number of angiographical collateral arteries.

How it works

Arteriogenesis, the growth of collateral arteries, can be achieved with a regimen of intermittent pneumatic compression, as we’ve just seen. But what actually happens inside the vessels?

Rapid compression causes shear stress on the endothelial cells. These cells react by releasing nitric oxide (NO), which acts as a vasodilator, and tissue factor pathway inhibitor (TFPI), which acts as an anticoagulant. These two substances ease the path of nutrient-rich blood through the collateral arteries.

Within a month, patients with peripheral arterial disease (PAD) typically begin to see a dramatic increase in arterial blood flow if they use the ArtAssist® device every day.

After about 90 days, the benefits can be visualized in an arteriogram, as seen above. After this point, a patient may be able to discontinue ArtAssist® device therapy.

Obtaining therapy

Both physicians and patients can contact ACI Medical for information and ordering:  toll free (888) 453-4356 or info@acimedical.com

More detailed information can be found at acimedical.com/artassist/order.

References

Angiographic Improvement After Rapid Intermittent Compression Treatment (ArtAssist®) for Small Vessel Obstruction
van Bemmelen, P.; Char, D.; Giron, F; and Ricotta, J.J. Department of Surgery, Division of Vascular Surgery, State University of New York and Stony Brook, NY, USA. Ann Vasc Surg 2003;17:224-228

Long-term Intermittent Compression Increases Arteriographic Collaterals in a Rabbit Model of Femoral Artery Occlusion 
van Bemmelen, P.S.; Choudry, R.G.; Salvatore, M.D.; Goldenberg, B.I.; and Blebea, J. Departments for Surgery, and Pathology, Temple University, Philadelphia, USA.
Eur J Vasc Endovasc Surg 34, 340-346 (2007) 

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Help for your arteries with the ArtAssist® pneumatic compression pump

When you think of pneumatic compression pumps, what comes to mind? A lot of people would say lymphedema, as they are very common.

However, the ArtAssist® device should not be confused with lymphedema treatment because the ArtAssist® device solves an entirely different problem:  facilitating arterial blood flow to the places that need it, especially in the legs and feet (there are also cuffs available for arms, though it is somewhat less common).

So, for example, if you have atherosclerosis (hardening of the arteries) of the lower extremity or a diabetic foot ulcer, your problems would not be solved with a lymphedema pump. Depending on the nature and severity of your arterial disease, you would be better advised to use the ArtAssist® pump.

Researchers have discovered that, unlike lymphedema pump technology, the ArtAssist® device promoted what we call arteriogenesis, or collateralization These two synonyms refer to the opening of small collateral arteries that already naturally bypass the obstructed artery. We all have these small collateral arteries, but when the main artery has no blockages, the collateral ones aren’t needed.

In this case, a person with a blocked artery needs to take action so that blood gets where it needs to be. Sometimes, people make lifestyle changes, such as dieting and exercising. Other times, people take medication to improve blood flow. And in more severe cases, people resort to surgery such as bypass and endovascular.

The problem is that some people exhaust all of those options and vascular surgeons believe they have no other choice but to amputate – but that’s not true! There is actually one last shot at limb salvage for these patients, and that is the ArtAssist® device. In one clinical study, it was shown to have up to a 94% limb salvage rate even after 3.5 years.

Do be advised, though:  no one would ever recommend that you let it get to the point of amputation. As with all diseases, the earlier you solve the problem, the better.

If you or someone you know could use the ArtAssist® device as a non-surgical solution for PAD, please call our toll free number 888-453-4356 and ask to talk to Don or Lindsay. If you contact me (via WordPress, Twitter, Facebook, email, etc.), I will refer you to either of the two people I just mentioned as quickly as I can – we know how important limb salvage is.

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Paul van Bemmelen, MD, PhD: Arterial Pumps for Limb Salvage and Wound Healing

paul van bemmelen md phdLast October, Dr. Paul van Bemmelen gave a presentation at the podiatry conference Superbones West about using arterial pump technology to treat peripheral arterial disease of the lower extremities.

Click on the link below to view the presentation – it lets you skip to the parts you want to see!

Arterial pumps for limb-salvage and wound-healing

Dr. van Bemmelen’s personal blog:  PaulvanBemmelenMD.wordpress.com

 

 

ArtAssist Arterial Assist Device

ArtAssist®…The Arterial Assist Device®

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