Sequential Pneumatic Compression Biomechanical Home … · ORIGINAL RESEARCH Vascular Disease Management ® July 2016 147. Sequential Pneumatic Compression Biomechanical . Home Therapy

ORIGINAL RESEARCH

Vascular Disease Management® July 2016 147

Sequential Pneumatic Compression Biomechanical Home Therapy Device in the Management of Critical Lower Limb Ischemia for No-Option Patients

Sherif Sultan, MCh, MD, FRCS, PhD1,2; Wael Tawfick, MBBCh, MSc, MRCS1; Mohamed Zaki, MCh, MRCS, MD1,3; Mohamed Elsherif, MCh, MRCS1; Mohamed El Sharkawy, MBBCH1; Edel P. Kavanagh, BSc, PhD1; Niamh Hynes, MRCS, MMSc, MD1,2 From 1Western Vascular Institute, Department of Vascular and Endovascular Surgery, University Hospital Galway, National University of Ireland, Galway, Ireland; 2Galway Clinic, Royal College of Surgeons of Ireland affiliated hospital, Doughiska, Galway, Ireland; 3Vascular Surgery Department, Ain Shams University, Cairo, Egypt.

ABSTRACT: Critical limb ischemia (CLI) causes pain, skin ulcers, and sores, and it leads to an unacceptable

quality of life. Sequential pneumatic compression (SPC) has been proposed as an adjunct to best medical

care, aimed at preventing amputation, relieving pain, and promoting wound healing by recruiting the

nonfunctional capillary bed and increasing blood flow in distal limbs. Our tertiary referral center conducted

a study to determine the efficacy of SPC in patients with CLI between 2005 and 2015, where patients

were commenced on a 12-week treatment protocol. Sustained clinical improvement was 68% at 1 year.

Thirty-day mortality was 0.6%. Limb salvage was 94% at 5 years. Freedom from major adverse clinical

events was 62.5% at 5 years. All-cause survival was 69% at 4 years. From 2010 to 2015, 20 limbs

(7.6%) underwent major amputation out of the 262 limbs studied. Amputation-free survival was 98% for

those who acquired the device and 90% for those who did not at 6 months, and 96% and 84% at 1 year,

respectively. SPC is a valuable tool in the armamentarium for CLI therapy. It achieves rapid relief of rest

pain without any intervention in patients with limited life expectancy. It reduces minor amputations and

adjourns major amputations, although it does not significantly lessen the incidence of inevitable limb loss.

VASCULAR DISEASE MANAGEMENT 2016;13(7):E147-E155

Key words: SPC ArtAssist; CLI; amputation; limb salvage; capillary bed

Critical limb ischemia (CLI) causes pain,

skin ulcers, and sores, and it leads to an

unacceptable quality of life. The 5-year

mortality for patients with CLI is 70%. Of those,

35% are cardiovascular deaths.1-4 Previous studies

have signalled an increase in the incidence of am-

putations, which may be attributed to cardiovascu-

lar atherosclerotic burden, the pandemic of diabetes

mellitus, and an aging population.5-7 This predicts

an increase in the number of major amputations

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over the coming decades. CLI is a serious condi-

tion with dire consequences. After 1 year, only half

of the patients diagnosed with CLI will be alive

without a major amputation. Approximately 25%

would have undergone a major amputation, and

the remaining 25% would have died.8 Unmanaged

patients with CLI are associated with high subse-

quent morbidity and mortality due to the associated

prohibitive cardiovascular risk factors.

Revascularization is not always a viable treatment

option, either due to the poor general condition of

the patient or due to the absence of reconstructable

vessels. Despite advances in vascular surgical and

interventional radiologic techniques, up to 14% to

20% of patients with CLI are not suitable for distal

arterial reconstruction, owing to occlusion of crural

and pedal vessels.9 Subsequently, up to 70% of all

patients with CLI are amputation bound.

Sequential pneumatic compression (SPC) has been

proposed as an adjunct to best medical care, aimed at

preventing amputation, relieving pain, and promot-

ing wound healing by increasing arterial blood flow

Figure 1. The ArtAssist unit (ACI Medical).

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in distal limbs.10 It has been shown to achieve wound

healing and limb salvage in patients with severe in-

frapopliteal disease and limb-threatening ischemia

who are not suitable for revascularization.11-13 SPC

increases flow to the lower limbs. It generates up to

a 4-fold improvement in popliteal artery blood flow,

with modulation and recruiting of the capillary bed

and collateral circulation enhancement.11,14-17

TECHNIQUE

Sequential Pneumatic Compression

The device described is the ArtAssist (Figure 1;

ACI Medical). The mechanism of action of the Ar-

tAssist is to increase arterial blood flow. It applies

a massage-like compression to the foot, ankle, and

calf to circulate blood flow at a maximum inflation

pressure of 120 mmHg, minimum deflation pres-

sure of 0 mmHg, inflation rise time of 0.3 seconds,

and inflation time of 4 seconds followed by 16 sec-

onds of deflation, resulting in 3 compression cycles

each minute. This compression regimen simulates

the beneficial effects of brisk walking, without pain.

Firstly, the device compresses the foot and ankle.

One second later, the calf is compressed. As a result,

the foot, ankle and calf veins are almost completely

emptied. In return, the arterial blood is more easily

pushed down to the toes and blood-deprived tissues.

Because of this mechanism, blood flow to the skin

of the feet can be tripled.

A second mechanism of action that accounts for the

large blood flow increase involves the endothelium.

Endothelial cells release important biochemical fac-

tors, such as nitric oxide that aid circulation of the

blood. Rapid cyclic blood flow induces high shear

stress that promotes the endothelial cells to gener-

ate and release nitric oxide, tissue factor pathway

inhibitor, and endogenous tissue plasminogen acti-

vator.18-20 Since these biochemical factors dissipate

after approximately 17 seconds, the device repeats

the compression sequence three times per minute.

This means that in a one-hour session, the patient’s

arteries will be expanded almost 200 times.

Numerous postulated theories in relation to the

mechanism of action of SPC include emptying of the

plantar venous plexus and reduction of the venous

leg pressure, increasing the arteriovenous pressure

gradient, and increasing shear stress in endothelial

cells of the lower limb vascular beds.15 An additional

mechanism is the momentary delay in the local va-

soregulation resistance of the venoarteriolar response

and the transient suspension of the arteriovenous

reflex hyperaemia, which both improves endothelial

function and induces collateral arterial formation.21

Improved endothelial function and formation of col-

laterals enhance capillary recruitment and decreases

peripheral resistance. Moreover, long-term effects

were provided from the enhanced angiogenesis and

collateral formation in response to the generation

and release of nitric oxide, tissue factor pathway in-

hibitor (TFPI), and endogenous tissue plasminogen

activator (tPA), secondary to increased shear stress

following rapid cyclic blood flow.

MATERIALS AND METHODSTo date, 2 studies have been conducted by our

tertiary referral center to determine the efficacy of

SPC in patients with CLI.22-24 The first study was

conducted between 2005 and 2012, in which 171

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patients with severe CLI who were not suitable for

revascularization were enrolled in the program. A

matched control group of 75 patients with primary

amputation was used. Primary endpoints were limb

salvage, sustained clinical improvement, and 90-day

mortality. Secondary endpoints were hemodynamic

outcomes with increase in popliteal artery flow and

toe pressure, and cost effectiveness.

The second study was conducted between 2010 and

2015, in which a total number 187 patients (262 limbs)

were enrolled in the SPC program. These patients were

retrospectively scrutinized to investigate the overall role

of SPC in limb salvage. Statistical analysis was used to

compare demographics, preintervention Rutherford

categories, major and minor amputation, and improve-

ment in rest pain among 2 groups of patients; those

who acquired the device and those who did not.

Criteria for Use

Patients included in this study were those with CLI

(Rutherford categories IV, V, and VI) defined as the

presence of rest pain, tissue loss, or gangrene along

with an ankle brachial pressure index of less than 0.5

and a systolic ankle pressure less than 50 mmHg.6

Patients included in this study were required to have

a nonreconstructable arterial tree either due to ab-

sence of anatomically suitable outflow (Figure 2) as

agreed upon by at least 2 vascular surgeons, or due

to unacceptable operative risk by the patient after

adequate explanation by a consultant anaesthetist.

Patients excluded from this study were those who

had intermittent claudication, and those who were fit

both anatomically and functionally for operative or

endovascular revascularization. In addition, patients

with extensive foot gangrene precluding attempts at

limb salvage, recently confirmed deep venous throm-

bosis, or an inability to tolerate compression were

excluded.

Protocol for Use

Patients were commenced on a 12-week home

treatment protocol that consisted of a minimum of

6 to 8 hours per day of use. Treatment was spread

throughout the day at 2 intervals. The device was

Figure 2. Angiography image of a “no-option” patient who is eligible for SPC shows blockage (arrow). AT, anterior tibial artery; TPT, tibioperoneal trunk.Cop

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applied to the symptomatic legs while the patient was

sitting upright in a chair. Some patients purchased

the machine and continued daily use in their homes.

Additional medical treatment was maintained in the

form of a dual antiplatelet (acetyl salicylic acid 75

mg once daily and clopidogrel 75 mg once daily),

naftidrofuryl 200 mg three times daily, and a statin

according to blood lipid levels, in addition to diabetic

control. Patients with infected foot ulcers were ad-

mitted, started on intravenous antibiotics, empirical

broad spectrum initially, then according to culture.

Necessary drainage and debridement were done and

exposed wounds were managed using negative pres-

sure wound therapy. Patients with congestive heart

failure were managed with diuretics, fluid restriction,

and optimization of their cardiac status.

Statistical Methods

Statistical analysis was conducted using SPSS v.6.

Evaluation of data such as Rutherford categories,

toe pressures, blood flow velocities, limb salvage,

amputation, and rest pain was conducted with the

paired t test or chi-square test, where appropriate.

Spearman’s correlation was used to investigate the

relationship between the duration of use of the de-

vice and amputation free survival. A P value <.05

was considered statistically significant.

RESULTSSeventy-five of the patients in the control group

had a Rutherford category of V and VI. Seventy-four

percent (n=171) of patients in the SPC group had

a Rutherford category of V and VI. Patients from

both groups were comparable, resulting in a Ruth-

erford P value of .138 (chi-square). Findings from

the patient group between 2005 to 2012 showed that

sustained clinical improvement was 68% at 1 year.

Mean toe pressure increased from 19.90 to 35.42

mmHg (P<.0001). Ulceration healed in all but 12

patients over the course of follow-up in the SPC

group. Mean popliteal flow increased from 35.44 to

55.91 cm/sec (P<.0001), and 30-day mortality was

0.6%. Limb salvage was 94% at 5 years. Freedom from

major adverse clinical events was 62.5%, compared

to 32% in patients with amputation at 5 years. All-

cause survival was 69%, compared to 38% for primary

amputation at 4 years. Median cost of managing a

primary amputation patient is €29,815 compared to

€3,985 for SPC. We treated 171 patients with the

ArtAssist unit at a cost of €681,965. In comparison,

primary amputation for 75 patients cost €2,236,125

(€3,988 vs €29,815 per patient respectively, a dif-

ference of €25,827, or approximately $29,205).

From 2010 to 2015, 20 limbs (7.6%) underwent major

amputation out of the 262 limbs studied. On evaluat-

Table 1. Comparison of Outcomes in Patients Using and Not Using the Device

Patients using device Patients not using device P value

Rest pain improved 91 9 <0.0001*Rest pain did not improve 55 45

Major amputation 16 4 0.714**Minor amputation 9 6 0.023**

Limb salvage 135 27 0.714***P value calculated using chi-square; ** P value calculated using likelihood ratio.

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ing the performance of the SPC device in the preven-

tion of amputation, there was no statistically signifi-

cant association between using the device and limb

salvage (P=.714). There was a statistically significant

correlation between minor amputation and inability to

obtain the device, suggesting evidence to support the

efficacy of SPC in preventing minor amputation and

improve healing of ulcers (P=.023) (Table 1).

Amputation-free survival at 6 months was 98% for

those who acquired the device and 90% for those

who did not, and at 1 year it was 96% and 84%, re-

spectively. There was a strong positive correlation

in toe pressures before and after application of the

device (P=.072) (Table 2). On exploring the effect

of the device application on rest pain, there was a

statistically significant likelihood that using the de-

vice would improve rest pain (P<.0001). Average

baseline pain numeric scale results were 7 out of 10

prior to usage of the device, 5 out of 10 at 3 months

(P=.049), and 4 out of 10 at both 6 months and 2

years after use.

Spearman’s correlation was used to investigate the

relationship between the duration of use of the de-

vice and amputation-free survival, and indicated a

weak negative correlation between the 2 variables

(P=-.07), however this proved to be statistically in-

significant (P=.39). The postulated hypothesis that

the longer the device is used, the more likely the

limb is salvaged was rejected.

DISCUSSIONIncidence of CLI has been exponentially increasing

over the last decade, especially with the graying of na-

tions and increased prevalence of diabetes.25 There is

also a lack of clarity regarding optimum management

when revascularization had been exhausted or is not

practical. This motivated us to evaluate the clinical

efficacy of SPC in amputation-bound patients with

CLI. Limb salvage with an improved quality of life

will continue to be the paramount ambition for most

patients referred to a vascular surgery practice. Given

the grave impact of amputation on social, vocational,

and economic factors with regard to both the pa-

tient and the community, any therapy that has the

potential to save a limb is worth evaluation.

Our experience shows that 10% of patients with

peripheral artery disease older than 50 years will de-

velop CLI within 5 years. The fact that more than

90% of those will never progress to CLI makes it

apparent that there is something particularly indo-

lent about the minority with CLI that makes them

susceptible to limb loss and therefore a priority for

therapy. Equally there may be an innately protective

mechanism in those with claudication that defends

them from the risk of limb loss.

Despite a modest improvement in medical thera-

pies since 1997, 1 in 5 patients still die or lose their

leg within a year and wounds and ulcers are more

likely to worsen.26-28 Although the exact reason for

Table 2 Comparison of Toe Pressures Before and After Device Use

Mean Standard deviation Mean difference Correlation coefficient P value*

Before 61.4 mmHg 29.7 -3.53 0.72 0.071

After 65 mmHg 31.1*P value and 95% confidence interval were calculated using paired t test.

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improvement is unclear, it is likely related to im-

proved medical care for patients with CLI as well as

improved clinical care of the comorbidities associ-

ated or existing with CLI. This translates to indirect

improvements in survival from comorbidities rather

than direct and so justifies an attempt at revascular-

ization whenever possible.

The TransAtlantic Inter-Society Consensus for the

Management of Peripheral Arterial Disease (TASC

II) recommends revascularization as the optimal

treatment for patients with CLI,1 but the type of

revascularization for patients with CLI, whether sur-

gical or endovascular, remains a subject of debate.

The evidence comparing the effect of these two

main interventions on mortality, morbidity, and limb

function remains inconclusive.

A recent systematic review and meta-analysis con-

cluded that until there are more robust data, the

choice of revascularization strategy depends on the

surgeon’s expertise as well as on the patients’ values

and preferences, expected perioperative risk, and

anticipated long-term survival.29 Given the broad

heterogeneity of this clinical syndrome, future stud-

ies should appropriately stratify patients to improve

the fidelity of outcomes, reporting, and methodology

of comparative effectiveness studies in this field. In

any case, revascularization, regardless of the method,

does not guarantee limb salvage. Therefore, a defini-

tive cure for CLI remains an unmet clinical need.

The ArtAssist is a valuable tool in the armamen-

tarium for CLI therapy. It achieves rapid relief of

rest pain without any intervention in patients with

limited life expectancy. Delis et al noted that SPC

increased blood flow, relieved rest pain, and limited

tissue damage in patients with CLI by generating a

3- to 4-fold augmentation in popliteal artery blood

flow, and verified that blood flow improvement was

sustained following cessation of SPC usage.14,15

Although limb salvage is essentially the utmost as-

piration for all patients referred for vascular surgery

services, unfortunately, some patients with CLI are in-

disputably superiorly managed with primary amputa-

tion. Regrettably, it is not always apparent beforehand

which patients will benefit from primary amputation

vs an attempt at limb salvage.23 In our case-control

study conducted between 2010 and 2015, we could

not formulate any association or added risk of any of

the patients’ comorbidities to major amputation and

subsequent limb loss. Hence, we could not predict

likelihood of limb salvage through patients’ demo-

graphic or preintervention patient comorbidities.

On investigating the efficacy of SPC as a treatment

modality to avoid limb loss and amputation in pa-

tients with nonreconstructable CLI, the results were

divisive. We could not find a statistically significant

correlation between duration of usage of the device

and limb salvage, and consequently rejected the hy-

pothesis that longer durations of device usage could

alter outcome. Although we could not deduce a

statistically significant difference in limb salvage rates

between those who utilized the device and those

who did not, SPC application significantly moder-

ates minor amputation in addition to significantly

protracting amputation-free survival. Moreover, in

patients presenting only with rest pain (Rutherford

category IV), there was a statistically significant im-

provement in rest pain, and consequently the quality

of life.

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CONCLUSIONSPC is a valuable tool in the armamentarium for

CLI therapy. It achieves rapid relief of rest pain

without any intervention in patients with limited

life expectancy. It reduces minor amputations and

adjourns major amputations, although it does not

significantly lessen the incidence of inevitable limb

loss. n

Editor’s note: Disclosure: The authors have completed

and returned the ICMJE Form for Disclosure of Poten-

tial Conflicts of Interest. The authors report no potential

conflicts of interest or financial support with respect to the

research, authorship, or publication of this article.

Manuscript received February 9, 2016; provisional accep-

tance given April 11; manuscript accepted May 25, 2016.

Address for correspondence: Sherif Sultan, MCh, MD,

FRCS, FACS, PhD, National University of Ireland,

Distillery Rd., Galway, Ireland. E-mail: sherif.sultan@

hse.ie

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tan S. Sequential compression biomechanical device versus primary amputation in patients with critical limb ischemia. Vasc Endovasc Surg. 2013;47(7):532-539.

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Sequential Pneumatic Compression Biomechanical Home … · ORIGINAL RESEARCH Vascular Disease Management ® July 2016 147. Sequential Pneumatic Compression Biomechanical . Home Therapy