Postgrad Med J: first published as 10.1136/pgmj.40.465.423 on 1 July 1964. Downloaded from POSTGRAD. MED. J. (1964), 40, 423

THE MANAGEMENT OF PERIPHERAL ARTERIAL EMBOLI

A. G. RIDDELL, M.B.E., M.S., F.R.C.S. W. McN. ORR, M.B., F.R.C.S.(Ed.), F.R.C.S. Department of Surgery, University of Manchester and Manchester Royal Infirmary.

ONE of the main difficulties in assessing the who also achieved the first successful aortic results of any surgical procedure is the pro- embolectomy in England, as reported by Grif- vision of a directly comparable series of patients fiths (1938). Since then there have been periodic on whom it has not been employed. Nowhere changes of opinion with regard to the advisa- is this more evident than in trying to determine bility of performing embolectomy for acute the value of embolectomy in the management ischmemia in the lower ilimb. This difference of of peripheral arterial emboli. The problem of approach has been due to several factors. comparing the results of conservative and oper- Firstly, these patients are often very ill and ative management is considerable, due to the thus poor surgical risks, even for what may be fact that conservative treatment is employed in a relatively minor procedure. Many of them poor risk patients in whom surgery of any also have severe cardiac disease. Lastly, and kind is inadvisable and also in those patients perhaps the most relevant factor of all, emboli whose ilimbs are recovering spontaneously when are often multiple. In spite of this, Shaw (1956) by copyright. they are first seen. and Shumacker and Jacobson (1957) considered Peripheral arterial embolism is a grave con- a more aggressive approach was indicated on dition. This is evidenced by the fact that in the grounds that although some limbs might most published series of cases the mortality recover spontaneously, there was a consider- rate is in excess of 40 per cent whether embo- able incidence of disability due to minor but lectomy has been employed or not. It has nevertheless chronic ischemia. Others dis- even been suggested that in some series where agreed, including Metcalfe (1960) who found surgical intervention was extensively employed, a 35 per cent mortality associated with conserv- the mortality rate was higher than if conserva- ative management alone. http://pmj.bmj.com/ tive management alone was used. However, Surgeons would now agree that somewhere we feel this does not necessarily mean that between these two extremes lies the most surgery should not be advised. Although the desirable course. The problem of accurate overalil results are poor in terms of mortality selection, however, remains. and loss of limb attributable to the natural history of the disease, a worthwhile result can Pathology

be achieved in a minority of patients whose Whereas the most common clinical problem on September 30, 2021 by guest. Protected limb would not otherwise be restored to normal associated with arterial embolism is concerned function. Tihe problem of selection of those with occlusion of the vessels of the lower limb, patients who are likely to benefit from embo- the cerebral and visceral vessels and those of lectomy is difficult if not impossible. It is the upper extremity may also be affected. In therefore inevitable that the procedure will be these latter situations therapeutic considerations employed in a number of instances where the will be modified by several additionail factors. eventual outcome is fatal. First, the location may be inaccessible as in the case of the cerebral vessels. Secondly, there Historical Review may be no collateral circulation as in the case The pathology of embolism was first of the abdominal viscera, and irreversible described by Virchow in 1854. It was not until changes may rapidly supervene. On the other half a century later, however, that surgical relief hand, embolic occlusion of the vessels of the of the condition was attempted. upper extremity is attended with a high rate The first successful embolectomy in this of spontaneous recovery due to the ready country was performed by Jefferson (1925), response of the collateral circulation. Postgrad Med J: first published as 10.1136/pgmj.40.465.423 on 1 July 1964. Downloaded from 424 POSTGRADUATE MEDICAL JOURNAL July, 1964 The source of arterial emboli is usually the main vessel and vessels forming potential col- left side of the heart, although the causative laterals may also be present and is presumably condition is not always apparent or demon- mediated by local nervous reflexes. Thus a strable. Many of the patients seen have some clinical picture of acute ischmemia may be pro- cardiac irregularity such as atrial fibrillation. duced. The onset of irreversible tissue changes As one would expect the commonest associated will depend on the readiness or otherwise of condition is mitral valve disease. Next in fre- the collaterals to develop. The onset of distal quency is arteriosclerotic heart disease, particu- thrombosis and the rate at which it progresses larly in those patients who show clinical or may also limit the extent to which the col- other evidence of myocardial ischemia. Occa- lateral circulation can develop. However, no sionally the source of emboli is not clear, and definite time interval can be placed on this instances have been reported of emboli arising sequence of events, one can only attempt to from the wall of the aorta itself, especially in assess it clinically. the presence of an aortic aneurysm or gross One further important point should be men- atherosclerosis. In approximately 10 per cent tioned, namely the presence of pre-existing of cases, no cause can be found. Some of arterial disease. Whereas in normal vessels these, however, may well originate as a mural emboli tend to become impacted at bifurcations thrombus secondary to a "silent" myocardiall in the case of vessels previously narrowed by infarct. arterial disease this is not necessarily so. In While most embolic occlusions are clinically such cases the location of the embolus may manifest as instances of acute or subacute be a point of narrowing in the artery, at for ischaemia, symptomless emboli do occur. The example, an atheromatous plaque. This feature mechanism here is difficult to explain. It may is of considerable importance, for it may mean be that because of narrowing of the vessel by that as some collateral circulation is already

pre-existent disease the collateral circulation present, the impact of sudden occlusion mayby copyright. has already been partially developed. not be so dramatic. Emboli tend to become lodged or impacted When a considerable volume of ischemic at arterial bifurcations. This is due to the tissue has been present for some time, restora- fact that when an artery divides its branches tion of blood flow to the part may liberate are correspondingly reduced in size. The com- the many harmful products of anerobic metab- mon sites of impaction then in the lower olism. This, in turn, may give rise to kidney extremity are the bifurcations of the aorta, the damage and a condition simulating the crush common femoral and popliteal arteries; of syndrome. Other metabolic and homeostatic these the common femoral is the most fre- problems may also be callled into play in certainhttp://pmj.bmj.com/ quently seen. In the case of the upper limb circumstances. It is possible that such factors the distal brachial artery will be the usual may play a part in the alleged increased mor- location, although an embolus may also become tality following embolectomy. lodged more proximally. An embolus usually Diagnosis produces complete occlusion of an artery or In most cases an accurate diagnosis of arteries or at least does so promptly when aided embolic occlusion of a major limb vessel can by spasm and the formation of a secondary be made on the mode of onset and the clinical on September 30, 2021 by guest. Protected clot. Occasionally, however, a partial occlusion examination. The presence of a pulseless, is found which will allow the passage of some painful, cold and anxesthetic limb in which blood distally. As well as occluding a main the skin is often white or mottled in colour is artery and its bifurcation, several smaller but unmistakable. Frequently motor activity is nevertheless important vessels which might form absent or at least reduced. Whereas most of collaterals may also be occluded, where they these physical signs are usually present in any arise close to a bifurcation. It must also be one case, pain is not necessarily so. In fact, remembered that multiple small emboli in some patients may assert that they have no the presence of severe spasm may simulate a pain, but that the limb feels "dead" or limp. complete more proximal occlusion. The absence of pulsation, coldness and sensory Following the occlusion, complete cessation loss of stocking distribution are the most of blood flow occurs distally and this favours reliable signs. Occasionalily sensory loss is thrombosis. Some clotting may also occur equivocal. Finalily, the presence of an irregular proximally but this is of less importance from pulse with or without other evidence of heart a technical point of view. Spasm affecting the disease will be strong confirmatory evidence. Postgrad Med J: first published as 10.1136/pgmj.40.465.423 on 1 July 1964. Downloaded from July, 1964 RIDDELL and ORR: The Management of Peripheral Arterial Emboli 425 Whereas the diagnosis of embolism is rela- ing on the duration of symptoms. Firstly, there tively easy, recognition of the site of the occlu- may be signs of improvement even when this sion may not be so simple. Accuracy of can only be deduced from the history. On the diagnosis can be influenced by the bodily con- other hand there may be continued deteriora- figuration of the patient. When the subject is tion. Severe tissue damage may have occurred obese the peripheral pulses may be difficult in the digits in the form of intense discoloura- to feel even in the most favourable circum- tion. Frank gangrene takes several days to stances. It is therefore essential to have some develop. There may also be muscle tenderness. other means of assessment. This is afforded While this is strongly indicative of muscle by the level of sensory loss and the presence necrosis it does not necessarily mean that of a marked temperature gradient. Reliable irreversible changes have taken place. We confirmation of the absence of adequate arterial have seen complete functional recovery in two flow will be obtained by employing an oscillo- limbs in which muscle tenderness was initially meter. present. When the aortic bifurcation is occluded by The differential diagnosis is firstly from an an embolus, signs will be present in both legs. acute arterial thrombosis. A more gradual The femoral pulses will be absent and sensory onset, together with a previous history of in- and temperature loss will be evident as high sufficiency in the limb, is more indicative of as the groins. There is usually complete loss of a thrombosis in the absence of any obvious motor power at least as high as the knee. The source of embolus. However, emboli may proximal level of the occlusion may be con- sometimes be derived from a "silent" source. firmed by palpating the abdomen above the When in doubt it is safer to err on the side umbilicus. of an embolic episode and to submit it to the In the case of a common femoral embolus last method of diagnosis, namely it is exploration, important to realise from the outset that provided surgery is indicated. Occasionally a by copyright. femoral pulsation may still be present. This localised dissection of a vessel can occur and is particularly the case if the profunda is given by narrowing its lumen induce a thrombosis off some inches below the inguinal ligament. simulating an embolus. Ilio-femoral venous One is therefore able to palpate the artery thrombosis frequently seems to cause con- above the embolus. In some patients the artery fusion in diagnosis. Here, however, the onset at the site of impaction is tender and we con- is gradual and is measured in days rather sider this a most reliable indication of the than hours. Although the limb feels heavy location of the embolus. Other signs include and weak due to the associated swelling (which sensory loss' to the level of the knee or mid- is rarely seen in arterial disease) there is no http://pmj.bmj.com/ calf,' together with a sudden temperature drop loss of sensation or motor activity. Though at the same level. Incidentally, in assessing the pulses are difficult if not impossible to temperature gradients one should compare the feel, oscillometry will reveal adequate arteriail limb with the opposite side as sudden gradients circulation. do occur at this level in the normal. Ankle Emboli are multiple in 40 per cent of cases. and popliteal pulses will be absent. Popliteal Therefore no olinical assessment is complete embolus, on the other hand, produces ischmmic a without diligent search for the presence of on September 30, 2021 by guest. Protected changes in the foot or lower leg, and motor other emboli. It is of particular importance activity is rarely impaired. to examine the abdomen carefully and also In the upper limb the diagnosis is easier as to test the urine. It is also not unknown for the pulses are more readily palpable, and pro- an embolus to break up at its site of impaction viding the occlusion is not too far proximal into severall fragments which are carried distally. the site of occlusion can be detected by the Therefore, if there appears to be an embolic use of the oscillometer. occlusion of the vessels of one leg the other leg It is important from the outset to know the should also be carefully examined. duration of symptoms as accurately as possible. On this time interval and the findings at the Treatment first examination, a baseline is formed on which one It has been intimated that as arterial embo- can note further deterioration or improve- lism is a serious condition, there are good ment. This information is vital from the point grounds for recommending conservative of view of treatment. management. This is due to several factors. Various other signs may be present depend- First, emboli are often multiple and may involve Postgrad Med J: first published as 10.1136/pgmj.40.465.423 on 1 July 1964. Downloaded from 426 POSTGRADUATE MEDICAL JOURNAL July, 1964 vital centres where they are inaccessible to Aortic Embolectomy treatment. Secondly, the patient may be gravely We feel confident the most satisfactory tech- ill from associated cardiac disease. Lastly, nique is a direct approach. While retrograde embolic occlusions in the lower limb have a evacuation of the clot via the femoral arteries fair chance of spontaneous recovery. However, can be achieved, some clot may remain unde- in spite of these factors we feel that operative tected at the bifurcation and give rise to further treatment has an important part to play. We trouble. Therefore, unless the patient is very base this view on the presence of a small ill, we prefer a laparotomy. Both techniques are number of patients who by operation are relatively straightforward. Any abdominal restored to complete function, for whom the incision wil,l do that provides adequate exposure withholding of surgery would be attended with of the aortic bifurcation. Having done so and the risk of chronic limb ischamia or even confirmed the diagnosis the aorta and both amputation. common iliac vessels are defined and slings Our indications for surgical treatment then passed around them. Care should be taken not are as follows: Any patient with clinical evi- to disturb the clot. The aorta is then clamped dence of embolic occlusion of a major limb proximally and a longitudinal incision is made vessel should be considered if there is not in the wall of the aorta just above its bifur- marked evidence of early spontaneous recovery. cation. It is then a simple matter to remove the In some sites the incidence of adequate spon- clot. Brisk back bleeding from both common taneous recovery is high. Such is the case in iliac arteries is very reassuring at this point the upper limb where we have not seen a and when one is sure that all the clot has patient requiring amputation or suffering from been washed out the bleeding is controlled by post-ischaemic symptoms. A comparable situ- tightening the slings. Clamps are then applied. ation exists for popliteal emboli where although At this point, dilute heparin solution is the incidence of post-embolic symptoms is injected into the aorta and also distal to by copyright. the higher, they may not be of great significance iliac clamps. It is useful at this stage to con- to the patient. When an embolus lodges in firm that at least part of the back bleeding the superficial femoral artery, an adequate col- is from the external iliac arteries, and not lateral circulation develops for reasons already from the internal vessels alone. If not, then discussed. Thus the main clinical problem is both common femoral vessels are exposed one of management of proximal main vessel through separate groin incisions, and the occlusion in the lower limb, that is, the aortic, arteries carefully inspected. If clot is palpable, iliac and common femoral bifurcations. In then further arteriotomies must be made and these sites the likelihood of spontaneous recov- the clot evacuated. Having confirmed that nohttp://pmj.bmj.com/ ery is slight and even if amputation can be further distal clot is present as judged by back avoided the patient may experience severe bleeding the arteriotomies are sewn up with chronic ischaemia, such as severe claudication fine continuous silk and the clamps removed. or even occasional mild rest pain. If embo- Oozing from the arterial wounds is controlled lectomy can restore normal circulation in these by pressure with a gauze swab. Observation cases the advantages are obvious. of the legs, which should be left uncovered

Although emboli are frequently mu,ltiple, throughout the procedure, will reveal if on September 30, 2021 by guest. Protected this cannot be forecast and so should not consti- adequate flow has been restored. There should tute an objection to surgery. The main contra- be signs of immediate improvement in colour indications, in our opinion, are as follows: and temperature. Provided that there has not An extremely ill patient who would not tolerate been undue delay in performing the operation, an operation in any form; marked signs of a reactive hyperemia will be apparent. clinical improvement within eight hours of the Although restoration of ankle pulses is grati- incident, and the presence of definite and irre- fying at this point, it is in fact unusual and versible tissue damage. does not necessarily mean that organic obstruc- When mitral stenosis is associated with a tion is still present. If available, an arteriogram peripheral embolus, the possibility of correct- is useful in doubtful cases, whereby any residual ing the cardiac cause of the embolus must be clot or mere spasm distally can be detected. considered. Opinion is divided as to whether Performing an aortic embolectomy via the the cardiac operation should be undertaken common femoral arteries while less satisfac- at the same time as the embolectomy, or tory, has its advantages in the very ill patient delayed until the earliest favourable occasion. provided it is successful. It may be performed Postgrad Med J: first published as 10.1136/pgmj.40.465.423 on 1 July 1964. Downloaded from July, 1964 RIDDELL and ORR: The Management of Peripheral Arterial Emboli 427 uinder local anesthesia. The embolus can be Conservative Treatment removed either by suction, using a catheter, The details of conservative management are or alternatively by employing a wire loop or widely known. Of the many techniques directed spiral such as is used for disobliteration. If at saving the limb, keeping it cool in relation- anything less than full flow is obtained when ship to the rest of the body and slight depen- the clot is removed then the aortic bifurcation dency, are the most important. The place of should be exposed to rule out the presence of anticoagulants is rather more obscure and any residual clot. This ilatter factor may well general agreement has not yet been reached. be responsible for the persistence of marked Their theoretical value directed to limiting the spasm in some cases. extent of distal clot formation is not entirely convincing. Low molecular weight dextrans may have some future in this field. Whether Femoral Embolectomy anticoagulants prevent the occurrence of fur- Regarding the technique of common femoral ther immediate emboli is questionable. Ener- embolectomy there is little to be added to the getic measures to correct any heart failure well known general principles. Removal of or other associated disease should be promptly th.e distal clot is again the main consideration. undertaken. We would emphasise that preven- We have found a moderately firm polythene tion of hypotension is of the greatest impor- catheter very useful for this purpose. This is tance, not only in conservative management advanced down the superficial femoral artery but also during and after surgery. and when in position strong suction is applied. While the use of sympathetic nerve block It is then slowly withdrawn. If retrograde flow in the acute phase of ischaemia is uncertain, it is not satisfactory after removal of the embolus should be employed in cases following surgery and its secondary clot, then exploration of the when severe spasm is persistent. Its more wide- popliteal artery is spread employment as part of routine conserva- imperative. This is most by copyright. readily done by a longitudinal incision one tive treatment has the usual theoretical dis- hand's breadth behind the medial border of advantages. However, it is of the greatest help the patella. It is helpful to have the patient's in the treatment of post-embolic ischemia, pelvis tilted to the same side and the hip and when it may be carried out as a paravertebral knee partially flexed. The popliteal space is block with Phenol, or lumbar sympathectomy. entered in front of and deep to the sartorius Conclusion muscle. Further downward exposure can be Conservative management must remain the readily attained by dividing the muscles standard method of treatment in the majority attached to the medial aspect of the upper of patients who suffer an embolic episode. It http://pmj.bmj.com/ end of the tibia and the medial head of gastroc- can be seen that the opportunities for achieving nemius. Provided these muscles are carefully lasting benefits from embolectomy are confined repaired later we have not seen any disability. to a small proportion of patients, whose exis- The popliteal artery can then be exposed tence, nevertheless, makes the procedure worth- down to its bifurcation with ease. From this while. A more profitable approach would be vantage point the anterior and posterior tibial the effective prevention of arteries can be explored with the catheter as recurrent embolic

episodes, and much work remains to be done on September 30, 2021 by guest. Protected previously described and any further clot in this field. We also await with interest any removed. We do not routinely anticoagulate forthcoming information on the value of low these patients, and the heparin administered molecular weight dextrans in the treatment of locally is small in amount. these cases. REFERENCES GRIFFITHS, D. L .(1938): Arterial Embolism; A Study of Eight Cases. Lancet ii, 1339. JEFFERSON, G. (1925): Report of a Successful Case of Brit. med. J., Hi, 985. Embolectomy, with a Review of the Literature. METCALFE, W. J. (1960): Arterial Embolism in the Lower Limb. Ann. roy. Coll. Surg. Engl., 27, 407. SHAW, R. S. (1956): A More Aggressive Approach towards the Restoration of Blood Flow in Insufficiency. Surg. Gynec. Obstet., 103, 279. Acute Arterial SHUMACKER, H. B. and JACOBSON, H. S. (1957): Arterial Embolism. Ann. Surg., 145, 145. VIRCHOW, R. (1854): Beitrage zur speciellen Pathologie und Therapie. Erlangen: Ferdinand Enke.