ATIIEROSCLEROSIS OBLITERANS

ATHEROSCLEROSIS OBLITERANS

ELMA CASELY

Adelaide

19

It has been suggested that those of uswho are ageing would do well to spreadour butter thin if we are inclined to athero­sclerosis, for the amount of cholesterol inthe blood plasma is thought to contributeto the degeneration of the arterial walls. Itis now a hundred years since LudwigVirchow, then professor of pathology at theUniversity of Berlin, observed the fattynature of the atheromatous lesion in theartery wall, although the first descriptionsof lesions which were undoubtedly arterio­sclerotic were made in the sixteenth century.

Our interest in the condition has beenaroused by the numbers of patients referredto us with peripheral vascular occlusion.The majority of these patients have athero­sclerosis obliterans and many of them havediabetes mellitus.

This paper describes atherosclerosisobliterans as it affects the lower extren1itiesand discusses treatment and prognosis.Detailed descriptions of the pathology,clinical features and treatment are given byAllen, Barker and Hines (1946), and hyBarrett and Fraser (1955); much of thematerial presented has been obtained fromthese books..

PATHOLOGY

Ath~rosclerosis obliterans is the mostcornn10n of the occlusive arterial diseasesand results in progressive or episodicocclusion of arteries. It is commonly,although not exclusively, a disease of laterlife" The large arteries of the lowerextremity, the iliac, femoral and poplitealarteries, are those most commonly affectedand often bilaterally so. The vessels toorgans such as the heart and brain may alsobe involved, complicating the treatment ofthe peripheral lesion. The arteries arefrequently tortuous, irregular in diameterand thickened. The nluscular coat of theartery becomes thin and irregular and maycontain deposits of calcium. Subintimalatheromatous plaques project into the lumen

of the artery and are among the earliestchanges which occur, appearing on theinternal surface of the vessel. They consist,in part, of connective tissue and phagocyticcells, most of which are loaded with fat.These atheromatous formations producepart of the occlusion of the artery andbecome the starting point for a thrombuswhich when large may completely occludethe artery. Smaller thrombi may bedeposited on the atheromatous plaque, fol­lo\ved later by irregular layers of thrombiwhich appear to be of different ages. Pro­gres~ive narrowing of the lumen results.

The essential components of the lesionare thus dec;tructive degeneration of themedial coat of the artery, atheroma andthrolnbosis.

No marked differences have been notedin the lesions of atherosclerosis obliteransin diabetic and non-diabetic patients, butthose with diabetes mellttus are often foundto have the condition in a severe form.

After an acnte occlusion the vessels distalto the site of block may constrict. This isto be expected if active intramural tensionis retained as the intravascular pressurefaIl,,_ However, if ischremia is continued,the small blood vessels lose their tone sothat they become dilated in spite of lowpressure. This accounts for the abnormalredness of the feet when dependent. Throm­bosis of many small vessels distal to theocclusion may occur as a result of the slowblood flow. Changes may also occur in thenerves in severe cases. They show peri­neural and perifascicular fibrosis. The skinis thin and inelastic and there is a loss ofsubcutaneous fat. In the toes the fat isreplaced by fibrous tissue, and they gradu­ally become hard and immobile. At thisstage osteoporosis develops.

SYMPTOMS AND SIGNSThese are the result of ischcemia. The

dorsalis pedis and posterior tibial pulsesare weak or absent, and the foot and lower

20 THE AUSTRALIAN JOURNAL OF PHYSIOTHERAPY

leg are cold. The foot 1nay be white, brightred or congested purple or black, althoughin some early cases the colour change isnot very noticeable.

I ntermtttent Claudication. In the earlystages intermittent claudication is usuallythe main symptom. After walking a cer­tain distance the cramp-like pain in the calfforces the patient to stand still for a fewminutes until it eases. The severity ofthis pain varies froul a heavy "toothache"while ,valking to an acute gripping painthat may come on after walking only afew yards and which may enforce rest. Asthe condition progresses, walking quicklyor ttp an incline accentuates the pain.

Resting Pain. A little later usually. thepatient begins to complain of pain whileresting, usually in the toes or heel. Thisis particularly severe at night and inter­rupts sleep. It is sometimes described as aburning pain, although the foot is cold totouch.

Colour Changes. The postural colourchallges in the feet may be very obvious.When the legs are elevated above heartlevel with the patient recumbent, for two orthree 1ninutes, the feet show an unnaturalpallor; if they are then allowed to hangover the edge of the bed, they become veryred. These changes usually indicate anadvanced degree of the disease, but theyare not always present. Sometimes, insevere cases with occlusion, no colourreturns to the foot when it has been depen­dent for thirty seconds or more, and theveins are slow to fill.

Sensory Disturbances. These are fre-quently present; numbness, "pins andneedles", shooting pains or burning sensa­tion~ are common. "Stocking" type ances­thesia is a serious symptolll which oftenprecedes gangrene; there is usually a pain­ful area where the anresthesia ends

Trophic Changes. Ulceration or gan-grene usually develops around the nails,on the terminal portions of toes or wherepressure has been applied, as may occuron the heel.

In advanced cases the condition is n10stdistressing. The patient is unable to bearhis foot to be covered by bedclothes, evenwith a cradle. Day and night his foot

sticks out of the bedclothes until it becomesso painful that to get relief he hangs itover the edge of the bed. There he sitsuntil the foot is cedematous and ilumobileand he persuades someone to anlputate itfor him.

PROGNOSIS

In general, the condition is progressiveand the prognosis for survival of theaffected extremity is not good. However,the lack of pulse in dorsalzs pedis andposterior tibial or popliteal arteries doesnot necessarily mean that the blood supplyto the extremity is blocked off completely.Jn patients with a long history of arterialinsufficiency in the limb it is probable thatcollateral circulation has developed, so thatunless there is a block of the main arter1alsupply to the extremity, for example, inthe iliac artery, there is a chance of savingthe leg if every care is taken. The survivalof the limb is frequently determined bytrauma of n1ild degree. Cutting a toenailor corn carelessly or a blister from a newshoe may ultimately lead to amputation.

TREATMENT

"freatlnent is directed towards improvingthe collateral circulation. Small arterialchannels from numerous sources enlargeto give what help they can to the strandedfoot. They are often large and pursue adevious course, sometimes from a point farabove the block to one below. Thoma, in1884, found that the growth of collateralblood vessels is directly proportional to theblood flow through them (Foley, 1957). Itis therefore necessary to encourage this flowin every possible way; the methods avail­able are reviewed in detail below.

The second aim should be to decreasethe disparity between the demand for bloodand its supply. It is thought that heatapplied to the cold extremity. is. contra­indicated on the grounds that it Increasesthe rate of metabolism without ensuring anincreased blood supply if a large artery isoccluded. The basal metabolic rate of manincreases roughly 7 per cent for every riseof one degree Fahrenheit in local tempera­ture. Massage, on the other hanel, reducesthe peripheral resistance to the arterial flowby aqsisting the venous return; it does not

ATHEROSCLEROSIS OBLITERANS 21

increase the metabolic rate.. It should begiven very gently to avoid injury to thefrail undernourished tissues, and as fre­quently as possible.. Occasionally in extremecases the limb is too painful to tolerateIna5sage, but very often we find that slowrhythmic effleurage for ten minutes withrelaxed hands improves the colour of theextrelllity and relieves the pain.

The third important aim of treatment isto inform the patient, in detail, of the carethat is necessary to avoid minor trauma..The sensitivity of ischcemic tissue cannotbe overemphasized. It is estimated thatin 50 per cent of cases gangrene is attribut­able to u1inor or major injury or to ill­advised treatment.

Instruction should be given about washingfeet and socks, the care of the skin and thefiling of toenails.. If toenails grow inwards,the patient should go to bed for a few days.Shoes must not irritate the naiL Cornsshould be protected. The corny layer maybe gently removed after prolonged soaking."Corn cures" are to be avoided. Exposureto cold, wet feet and crowded places wherefeet are trodden on are among many otherconceivable risks.

METHODS USED TO IMPROVE BLOOD FLOW

Various methods of assisting arterialflow and the developll1ent of collateral cir­culation are in use.

1. Reflex Heating by Applying Heat to theLumbosacral Region.

This depends on its efferent side on thesymFathetic nerves and does not occur aftersympathectomy. Heat releases vasodilatorsubstances, such as histamine, locally fromthe skin and other tissues. In addition,sufficient heat increases the temperature ofthe blood and stimulates heat receptors inthe skin.. These two peripheral effects arethen transmitted to the vasomotor centres,and reflex vasodilatation follovvs via thesympathetic nerves. To induce this reflexheating we give thirty minutes' shortwavediathermy, with pad electrodes over theabdomen and lumbar spine. The patientbecomes aware of the increased temperaturetn the calf of the leg and a rise of tempera­ture in the toes can be recorded in somecases.

2. BuergerJ s Exercises.WIth the patient horizontal and the limb

at the level of the heart, the pressure inthe limb arteries is approximately equal tothe pressure in the aorta.. \iVhen the limbis raised there is a fall in linlb arterialpressure proportional to the height to "\vhichit is raised above the heart; the pressurein the veins also falls.. The danger ofprolonged elevation of a limb with occlusivearterial disease is apparent; it seems advis­able not to elevate more than thirty degreesabove horizontaL When the leg is loweredthe pressure in the arteries is raised inproportion to the amount the limb islowered. After a short time the presssurein the veins, when they have filled, is alsoincreased.

Several questions arise fronI these con­siderations when giving Buerger's exercises ..Is it better to give ankle bending andstretching exercises in the dependent posi­tion, in the hope of keeping the venouspressure low, and so maintaining theunequal pressure bet\veen the capillariesand veins? Or are we, by exercising thecalf, causing retention of the arterial bloodin the muscles, instead of allowing gravityto carry it to the toes, where the need isgreatest? These questions cannot yet befully answered, but our practice is, when­ever practicable, to ask the patient to standup after the leg has been elevated andbefore he lie'3 ,vith it horizontal. vVhenthis is not possible the legs hang relaxedover the edge of the bed.

Massage, mainly effleurage, is given tothe legs each time they are horizontal whileBuerger's exercises are being given. Thepatient is also instructed to do deepbreathing many times a day to assist thevenous return to the heart and so decreasethe peripheral resistance to the arterialflow of blood.

3.. Walking..\iVhenever it is practicable, walking to

the limit of pain tolerance provides one ofthe greatest stimuli for the developmentof collateral circulation to the legs. Instressing the benefits of walking Foley(1957) quotes the case of a 67-year-oldwoman with advanced, long-standing andbilateral disease. In spite of associated

22 THE AUSTRALIAN JOURNAL OF PHYSIOTHERAPY

diabetes mellitus} cardiac failure, thrombo­phlebitis and gangrene of several toes.appropriate treatment, which includedarnbttlation at an early stage, resulted in herbeing able to do her own housework afterfive months. Prior to treatment she hadbeen bedridden for two months. Foleystates" "At first we used walking only inpatients with sharply localized gangrene,who had stabilized over a period of weeksor months. As our experience has increasedwe have used it in more recently developedgangrene. If the toes are involved weencourage the patient to hobble on the heel.If that too is involved, the foot is carefullybandaged, and weight bearing is distributedover the entire foot." We have used thismethod of walking in spite of gangrenoustoes with encouraging results.

We protect the toes or heel with thicklayers of cotton wool, use a slipper suitahlycut to avoid any pressure, and encouragethe patient to use the ankle as much aspossible. Sitting with legs dependent formore than a few minutes and standing stillshould be avoided.

4. Carbonated Baths or HistamineIonizat1,on

These procedures Inay be used to producevasodilatation locally, without raising thetissue metabolism. They are described byJ. S. Tobis and Karl Harpuder (1953)We have not used these methods, but theymay be useful when reflex heating isineffective.

.5. Osczllating Beds.These beds are of value for those patients

who are unable to walk for any reason. Ithas been shown that patients having bedrest are in negative nitrogen and calciumbalance.. It has also been shown that thisprocess is reversed if the patient is kept inmotion on an oscillating bed.

A PLEA FOR EARLY TREATMENT

Many patients are referred for physio­therapy only after one leg has beenamputated. Assistance is then requested forthe rehabilitation of an amputee rather thanfor preventive treatment to the remainingleg. In two patients in whom the remainingleg has been severely affected and amputa­tion was being considered, permission hasbeen given for treatment to be instituted~and the leg has survived. In the last fouror five years these patients have beentreated during the winter months withmassage, deep breathing and Buerger'sexercises, which they have done at leastthree times daily every day themselves, andwhen necessary small ulcers have been care­fully dressed until they have healed. Theyhave taken several short walks each day.

SUMMARY

The pathology, symptoms, signs andprognosis of atherosclerosis obliterans arereviewed" From the physiotherapeuticpoint of view, treatment is directed towardsimproving blood flow and towards decreas­ing the disparity between the demand forblood and its supply. Methods used toincrease blood flow are discussed in detailand particular emphasis is given to theimportance of walking" It is hoped thatthis paper will stimulate wider interest inthe condition and particularly in moredetailed care in the earlier stages.

REFERENCES

ALLEN, E V, BARKER, N. W, and HINES, E A,JR (1946), Pertpheral Vascular D1seasesW. B Saunders & Co, London

BARNETT, A J and FRASER) J R. E (1955),Per'Lpheral Vascular D'tsease MelbourneUnIversIty Press, Melbourne

FOLEY, W T (1957), "Treatlnent of Gangreneof the Feet and Legs by Walklng" C1rcula-t'ton, IS' 689

TOBIS) J. Sand HARPUDER} KARL (1953),"Physical MedICIne tn CardIovascularDiseases" Brtt J Phys Med} 16 133·