Peripheral arterial emboli

Peripheral Arterial Emboli

Mahlon C. Connett, MD, FACS, Concord, California Dwight H. Murray, Jr., MD, FACS, Napa, California Wendall W. Wenneker, MD, Napa, California

Interest in peripheral arterial emboli and associated embolectomy appears to have undergone a resurgence in the surgical literature in the last 5 years [l-6]. This is because the literature covering a series of acute arterial emboli, late and delayed arterial embolectomy, and the so-called conservative treatment of arterial embolectomy with heparin anticoagulation has resulted in controversies regarding appropriate management [I]. In general, the surgical literature relative to arterial embolectomy has as its source clinical material at teaching institutions, predominantly universities or large clinics [3,6-221. This report deals with the subject of peripheral arterial emboli and embolectomy in relatively small, private nonteaching hospitals in which patients with embolectomies were treated, and analyzed retrospectively. The study was carried out over a 12 year period from 1970 through 1981. Data with respect to age, sex, mortality rate, amputation rate, origin, and sites of emboli and a comparison of the mortality rates during the study period are presented. Because this series reports the results of a broad-based conglomerate of surgeons with different therapeutic persuasions, included are patients who have been treated with embolectomy or heparin as well as warfarin (Coumadin@). The results of these modalities of treatment are analyzed as well. Material

and Methods

From 1970 through 1981, all of the patients admitted to the hospitals with a diagnosis of peripheral arterial embolus were reviewed. The hospitals represent three private nonteaching hospitals. One hundred eleven patients were included, with a total of 130 emboli. There were 58 men and 53 women. The mean age of the patients was 72.8 years (women 75.3 years, men 70.5 years). We excluded patients with visceral emboli to obtain a group which could be Requests for reprints should be addressed to Mahlon C. Connett, M). 2425 Suite 10, Concord, California 94520. Presented at the 55th Annual Meeting of the Pacific Coast Surgical Association, Newport Beach. California, February 19-22, 1984.

EastStreet,

14

compared more readily with other series of comparable patients (Table I). The origins of the emboli are noted in Table II. The most common source of peripheral arterial emboli was arteriosclerotic heart disease with atria1 fibrillation, followed by mural thrombi after myocardial infarction and those that occurred after cardioversion. The site of emboli lodgement are noted in Table III. The common femoral artery was the most common site for embolic obstruction, being equally distributed between the right and left sides, followed by the superficial femoral and popliteal arteries. This group of patients was treated by embolectomy in 109 instances, anticoagulation alone in 18 instances, and anticoagulation plus embolectomy in 21 instances when the patient did not respond to heparin. An analysis in those 17 patients who received only heparin therapy revealed no consistent reason for the sole use of this therapeutic modality. Age and debility were not necessarily the common factors; instead the treatment employed was the one preferred by the clinician caring for the patient or was based on refusal of the patient to have surgical intervention. In all cases in which an embolectomy was performed, the classic Fogarty operation was peli”ormed with the patient under local anesthesia. General anesthesia was rarely employed.

Results The results are presented in Table IV. A result was considered good if there were pulses present, if there was an absence of pain, or both. A result was considered a failure when an amputation was required. Six amputations were performed at various levels with a total amputation rate of 5.4 percent. These were all performed on patients who had embolectomies. No patients treated with heparin had amputation. There was one death among those patients who had amputation. The overall mortality rate for the patients who had embolectomies was 13.7 percent. The mortality rate was also subcategorized according to time of death: early death occurred less than 72 hours after hospitalization or postoperatively and late death occurred more than 72 hours after

The American Journal of Surgery

Peripheral

TABLE I

Results of Other Series Limb Salvage Rate (%)’

No. of Patients

Mortality Rate (%)

1969 1964 1968 1973

110 78 38 194 246 260 82 75 50 91 85 149 98 83 50 124 49 100 26 128 19 125 174 80 47 47 74

27 19 42 27 24 29 43 29 20 15 41 20 22 40 40 30 16 26 31 19 16 26 27 31 17 28 27

46 47 63 60 54 76 74 69 82 66 66 55 57

1974

67

18

78

1970 1976 1967 1969 1972 1970 1963

41. 65 67 62 69 163 114

32 48 23 29 15 15 30

53 46 43 51 70 77 60

Authors

Date

Barker et al Billig et al Buxton et al Cranley et al Cranley et al Darling et al Edwards et al Erikseon et al Fogarty et al Fogarty et al Freund et al Green et al Creep et al Haimovici et al Hardin et al Hight et al Holm et al lnberg et al Karageorgis Krause et al Lazarides et al Levy et al MacGowan et al Martin et al McCann McMahon et al Muller-Wiesel et al Papasoglou et al Provan et al Romanoff et al Scheinin et al Tarnay Thomas Thompson et al Young et al

1966 1967 1969 1964 1970 1967 1966 1977 1965 1967 1975 1975 1972 1975 1965 1976 1972 1970 1967 1970 1969 1970

l

TABLE II

62 68 47 66 71 63 40 53 60 81 60 70 70

Estimated.

TABLE Ill

Arterial

Embolism

Origins of the Emboll Origin

n

ASHD with atrial fibrilation Myocardial infarction Unknown Atherosclerotic plaque emboli Following cardioversion Following arteriograms Cardiac valves Valve prosthesis Rheumatic heart disease with atrial fibrilation Popliteal aneurysm lntraaortic balloon

70 21 14 11 5 1 3 1 2 3 1

ASHD = arteriosclerotic heart disease.

hospitalization or postoperatively. The late mortality rate was 5.5 percent, and the early mortality rate was 8.3 percent. Seventeen patients were treated with heparin only. Five of these patients died, representing a mortality rate of 31.2 percent. In analyzingthe overall mortality rate with respect to age, the average age of those patients treated with embolectomy who died less than 72 hours postoperatively was 77 years. The mean duration of the embolus in all patients seen before institution of treatment was 12 hours (Table V). This represents a spectrum of duration of 1 to 21 days. The mean duration of embolus before embolectomy of those patients who died less than 72 hours after institution of treatment was 13 hours. The mean duration of the embolus before embolectomy of those patients who died more than 72 hours after institution of treatment was 10 hours. The causes of death in these two groups are noted in Table V. Only one patient is listed as having symptoms compatible with a postperfusion syndrome (hyperkalemia) [23]. It may, however, be that those eight patients whose

Sites of the Emboll Site Not Specified

Arterial Site

Right Side

Left Side

Bilateral

CFA SFA Popliteal Iliac Brachial Tibia1 Axillary Saddle PFA Subclavian Radial

21 13 18 10 8 4 4

21 8 3 6 3

1 2

.

.

4

“;

1::

...

.

..

.. 3

.. .. ..

4 . 1

1

TABLE IV

Total Number of Emboll Treated in 111 Patients (53 woman and 58 men)*

4

... ... 1

... . . ... ..

Treatment Total embolectomy Heparin only Heparin therapy failed with subsequent embolectomy Warfarin None

Emboli (n) 109 17 2

1 1

Mortality+ <72 h >72 h After After Admission Admission 9 (8.3) 5 (31.2) 1

0 0

6 (5.5) .

...

Amputation+ 6 (5.4) 0 0

0 0

Values in parentheses are percentages. + Total operative mortality rate was 13.7 percent. t Total limb salvage rate was 94.6 percent. l

CFA = common farnoral artery; PFA = popliteal femoral artery; SFA = superficial femoral artery.

Volume 148. July 1084

15

Connett et al

TABLE V

Analysis of Mortality

Patient Age

Duration of Embolus

82 79 79 91 87

24 h 8h 2h 48 h 13 h

Associated Disease

Cause

Early Death (less than 72 hours after admission)” Hyperkalemia Unknown Acute MI Unknown Unknown

COPD, CHF. ASHD with AF ASHD with AF, old cerebral infarct ASHD with AF ASHD, with brain syndrome ASHD with CVA _

Late Death (more than 72 hours after admission)t 89 ? 88 72

? lh 24h ?

74 76

? 4h

85

72 h

67 73 84

llh 8h IOh

Unknown Acute Ml Acute MI Acute cerebral thrombosis Acute MI Mesenteric thrombosis Unknown but gangrenous leg 6 weeks postop Unknown Unknown Unknown

Pacemaker, right femoral neck fracture Multiple pneumonia emboli ASHD, myocardial fibrosis ASHD, diabetes, old MI

Diabetes, hypertension ASHD ASHD, ASPVD

ASHD CVA, CHF, ASHD Ruptured esophagus, acute cholecystitis

’ Mean patient age and duration of embolus were 83.6 years and 13 hours, respectively. + Mean patient age and duratton of embolus were 77 years and 10 hours, respectively. ASHD = arterloscterotic heart disease; AF = atrial fibrillation; CHF = congestive heart failure; COPD = chronic obstructive pulmonary disease; CVA = cerebrovascular accident; MI = myocardial infarction.

causes of death were listed as unknown did, in fact, die from complications of postperfusion syndrome. The most common specific cause of death identified postoperatively was acute myocardial infarction. The mortality rate for the first half of the 10 year period was compared with that of the second half (Table VI). The mortality for the first half of the

TABLE VI

Year

16

Mortality

Over a 10 Year Period Total Embolectomy (n) , I

Death n

%

1970 1971 1972 1973 1974 1975

6 9 5 5 2 2

2 3 1 1 1 6

33 33 20 20 50 0

Mean Total

29

. .8

27 .

1976 1977 1978 1979 1980 1981

9 26 21 9 19 18

1 2 5 1 4 1

11 7.7 24 11 21 5.5

Total Mean

102

14

...

...

ii.+

period was 27 percent and in the second half it was 13 percent. The overall mortality of the surgically treated patients with peripheral emboli was 17 percent. Comments Surgical treatment of peripheral arterial emboli has an abundant historical and universal precedence [3,6,7-221. With the introduction of the balloon embolectomy catheter, the number and extent of arterial embolectomies increased [24]. In addition to simply removing the embolus, more extensive removal of propagated thrombus and fragmented emboli became possible. As a result, there has been an increased endeavor to increase limb salvage rather than to simply decrease the associated mortality, as had been the thrust in previously reported series [4,13]. Nevertheless, the mortality rates associated with embolectomy has remained high (range 15 to 48 percent) (Table I). Innovations in treatment of peripheral arterial emboli, in addition to the introduction of the balloon catheter, have included aggressive intervention for late arterial emboli [2,7,24,25] and aggressive, early surgical intervention for acute arterial emboli rather than relegating the surgical intervention to failure of heparin therapy. In contrast, there have been recommendations that peripheral arterial emboli be

TheAmerkenJmmelet&geq

Peripheral Arterial Embolism

treated conservatively without surgical intervention. In 1978, an impressive argument for conservative therapy was published [I]. In that series from San Francisco General Hospital, there was a mortality rate of 7.5 percent and an amputation rate of 26 percent. The series was otherwise unique in that the average age of the patients was low (59 years). In our series, the average age was 72.8 years. The purpose of our study was to evaluate the care of patients with peripheral arterial emboli in three private nonteaching hospitals, and to compare the results with those in series from large teaching institutions, regarding both mortality and amputation rates as well as methods of treatment [7]. In this series, the predominant treatment for peripheral emboli was embolectomy (Table IV). The total operative mortality rate was 13.7 percent. We submit that the deaths that occurred within 72 hours of surgery represent the true surgical mortality rate of 8.3 percent. The deaths occurring more than 72 hours after surgery probably reflect the mortality rate from the associated disease in this aged population (5.5 percent). One patient with an embolus to the distal superficial femoral artery with intermittently severe ischemia for a 5 hour duration was treated with warfarin with good results and the reestablishment of pedal pulses. Fifty-six percent of the emboli in this series were found in the aorta and the iliac vessel of the common femoral artery. Although these are the sites associated with the highest mortality rates and the highest associated complication rates with pulmonary emboli, venous thrombosis, and venous insufficiency [ZO],the mortality rate in this series was not confined to patients with emboli in these sites. During the first five years of this study there was a mortality rate of 27 percent (a third of the patients in the total series). The second 5 year period had a mortality rate of 13.7 percent (two thirds of the patients being treated during that period of time). It can be speculated that the advances in medical care, innovative cardiac drugs, and greater access to more sophisticated monitoring devices in suburban hospitals all may have played a role in improving the outcome. The age of the patients in this series was significantly older than in other reported series [3,6,7-221. In one 100 year old patient, a balloon embolectomy of an embolus in the common femoral artery and superficial femoral artery was successful with restoration of pulses postoperatively. Although the average age of the patients with emboli in this series was 72.8 years, it is noted in Table IV that the average age of those patients who died in the late postoperative period was 77 years. The mean duration of emboli for the entire series was 12 hours. The longest duration of an embolus in any patient included in the mortality figures was 72 hours. Although we adhere to the principle that early and aggressive embolectomy in the suitable patient probably should be maintained

as a principle of treatment, in our series it was not as influential to the outcome as was the age of the patient. Those patients who did fall into the mortality group were significantly older than those who survived. Of those patients for whom a cause of death was known, the majority died from acute myocardial infarction. Based on other data, however, seven of the eight unknown deaths were presumably related to pulmonary thromboembolic phenomena [20]. Late embolectomy was first advocated in 1959 [26]. Subsequently, others advocated late embolectomy, and there have been those who have advocated embolectomy whenever embolus was diagnosed [14,22,25]. In our series, there were 26 embolectomies that were performed for emboli that were present for more than 24 hours. Three of the patients who had late embolectomies died. One of the three died from acute pancreatitis and one died 6 weeks postoperatively after the onset of gangrene of the leg. Only one of these patients died from complications of the surgical procedure, representing a mortality rate of 3 percent. Delayed embolectomy, with or without associated reconstruction, appears to be a very viable therapeutic approach to the late discovery of peripheral arterial emboli. Perhaps the reason for this is the fact that an embolus of that duration has had ample opportunity to establish collateral flow, and although the leg may be ischemic, it does not fall into a limb salvage category. Summary One hundred eleven patients with 130 emboli treated in nonteaching private hospitals have been evaluated with respect to cause, mortality rate, and amputation rate. For surgically treated patients with balloon embolectomy, the mortality rate was 13.7 percent overall, with a limb salvage rate of 94.5 percent. The operative mortality was 8.3 percent. The mortality for late embolectomy was 3 percent with a limb salvage rate of 100 percent. The most critical factor in predicting mortality was age of the patient, with a significantly higher mortality in patients of advanced years. In this series, a prolonged duration of embolus before embolectomy did not have an adverse effect on the mortality rate. References 1. Blaisdell FW, Steele M. Allen RE. Management of acute lower extremity arterial ischemii due to embolism and thrombosis. Surgery 1978;84:822-31. 2. Elliott JP, Hageman JH, Szilagyi DE, Ramakrishnan V. Bravo JJ, Smith RF. Arterial embolization: problems of source, multiplicity, recurrence, and delayed treatment. Surgery 1980:88:833-45. 3. Field T, Lfttooy FN, Baker WH. Immediate and long-term outcome of acute arterial occlusion of the extremities. Arch Surg 1982;117:1158-80. 4. Gaspar MR. Arteriil embolism and thrombosis. Majj problems in clinical surgery. 1981;4:158-75. 5. Haimovici H. Cardiogenic embolism of the upper extremity. J Cardiovas Surg 1982;23:209-13.

6. Lawrtucr JE. Roder OC, Hansen HJB. Peripheral arterial ernb&km. Aota Chir Stand 1980;502:11 l-6. 7. Brkw ff, RoreroFE,Fob&s 6. Peripheral arterial embolism. %ug Gyneool Obst 1966;123:22-6. a ml% kWr?m U, Cooley DA. Arterial embolism. Arch Surg 1961;91:1-6. 9. MLlg AC, Au&en WG, Linton RR. Arterial embolism. Sorg w obstet 1967;142:106-14. IO. De -au RC, Castromil E, Barreiro A, et al. Therapeutic m and results in 336 arterial emboli. J Cardiovas Surg 1978;88:68-74. 11. M vad. Pietri J, Fontaine JL, Wuyts JL. Erfahrungen bei da b@hnndlungvon 548 atteriellen embolien. MMW 1966; 16:~903. 12. Feud U. Ranenoff H, Floman Y. Mortality rate following lower #nb artMa embolectomy: causative factors. Surgery 197&77:201-7. 13. m AM, LkWeese JA, Rob CG. Arterial emboktomy before and after Fogarty catheter. Surgery 1975;77:24-33. 14. M&t m, Tilney NL. Couch NP. Changing clinical trends in z wlth peripheral arterial emboli. Surgery 1976;79: 16. krberg MV. Scheinin TM, Vanttinen EA. Surgical experiences In acute peripheral ischemia (special reference to embolectomy in the aged). J Cardiovasc Surg 1970;11:114-21. 16. Kr&mRJ, Cranley JJ, Harner CD, Fogarty TJ. Further experiences wlth new embolectomy catheter. Surgery 1965;59: 81-7. 17. Levy R, Butcher HR. Arterial emboli: an analysis of 125 pat&@s. Sugery 1970;68:968-73. 18. MocQdwna WA, Mooneeram R. A review of 174 patients with artala embolism. Br J Surg 1973;60:894-8. 19. Saylm~ A, E&men 6, Bozer AY. Arterial embolism: an analysis of 115 surgical procedures. J Heart J 1974;15:554-9. 20. StaMone RJ, Blaisdell FW, Cafferata HT. Levin SM. Analysis of z2;, mortality from arterial embolectomy. Surgery 21. w

22. 23. 24.

25. 26. 27.

.k Slgler L, Raut PS, Austin DJ, Patman RD. Arterial eM&&omy: a 20-year experience with 163 cases. Sqery 1970;67:212-20. Yam@ R, tM@ries AW, DeWolfe VG, LeFevre FA. peripheral arts&al embolism. JAMA 1963;185:621-7. Mukk S. The tourniquet in operations upon the extremities. Surg @necol Obstet 1978;146:821-5. Foorty TJ, Cranley JJ, Krause RJ. Strasser ES, Hafner CD. A melhod for extraction of arterial emboli and thrombi. Surg w Obstet 1962;116:241-4. sparc#r FC, Eiseman B. Delayed arterial embolectomy. A new qt. Surgery 1964;55:64-72. kklmwlci Ii. Late arterial embolectomy. Surgery 1959;46: 775-86. Jarrett F, Dacurnos GC, Crummy AB, Detmer DE, Belzer FO. Late appearance of arterial emboli: diagnosis and management. Surgery 1976;86:898-903.

Discussion Thomas Fogarty (Palo Alto, CA): Drs. Connett, Murray, and Wenneker are to be congratulated for pointing out an important aspect that significantly influences both the mort&y and morbidity rates associated with acute arterial occlusion. The socioeconomic background of the patient as we11as the location of the medical facility influences not only the degree of ischemia but also the severity of the underlying disease. This fact is illustrated by the cumulative experience of Drs. Edward Harris, Roy Tawes, and myeelf from the inception of the embolectomy catheter in 1963 to the present. In the early part of our experience, there were two separate therapeutic modalities. In one, a group of 38 patients was treated with heparin alone for a

18

variety of reasons. In the other, embolectomy alone was performed in 61 patients. There were three deaths in the former group and eight in the latter group and four amputations in the former group and nine in the latter group. More importantly, subsequent to this early series and over the major portion of our experience, our primary therapeutic modality included both heparin and embolectomy. In Dr. Harris and Tawes’s group, there was a total of 280 patients. In our group there was a total of 360 patients. The contrast in death rates (8 percent for Dr. Tawes’s group versus 14 percent for our group), primarily reflects the difference in patient populations as influenced by the institution. In comparison with Dr. Tawes’s patients who came from a community hospital environment, our patients at Multnomah County Hospital in Portland represented a much more elderly age group that presented later in the disease process. The amputation rate, however, was quite acceptable in both groups (5 percent for Dr. Tawes’s group versus 6 percent for our group). Therefore, for the combined total of 640 patients in whom the primary and recommended therapeutic modality included both heparin and embolectomy, the first month operative mortality rate was 12 percent and limb loss was 5 percent. The overall mortality and morbidity rates for patients who underwent acute arterial occlusion therapy remain quite acceptable, and can be attributed to the combined use of heparin and surgery as the primary therapeutic modality. Also contributing to these results is the aggressive use of secondary reconstructive procedures when the primary operative embolectomy appears to be marginal or unsuccessful. Further, it is of critical importance to pay attention to and treat any underlying cardiac pathologic abnormality that may be responsible for the embolic episode. This paper has allowed us to more clearly appreciate the various factors that serve to influence the morbidity and mortality rates associated with acute arterial occlusion. Dean F. Winn, Jr. (Woodland, CA): I congratulate the authors on their fine results and concur in their approach to the treatment of peripheral arterial emboli. A recent patient provided some fascinating aspects to this problem. This 69 year old man presented with carcinoma of the right middle lobe of his lung. He gave a past history of an aortoiliac bypass in which the left limb occluded and was treated with a cross-femoral graft. The uneventful right middle lobectomy was completed at 3~00PM. Pain was well controlled by a continuous drip of epidural morphine at 0.5 ml per hour. At 1:00 AM, the patient complained of weakness and numbness in his lower legs. The intensive care unit nurse thought this was related to his epidural analgesia. By 8:00 AM the patient could only move his right great toe and was numb up to his mid thighs. The diagnosis of occlusion of his right iliac graft was made, and a right iliac embolectomy was carried out with restoration of circulation to the lower legs. However, he was left with prolonged weakness in his lower legs. The lesson gained from the outcome in this patient is that the type of anaglesia administered, that is, epidural morphine, can easily mask acute postoperative complications due to continuous relief of pain. The source of the embolus was the lung. The pathology report read “poorly differentiated adenocarcinoma similar to that found in the right middle lobe of the lung.” This also emphasizes the need for early venous ligation when feasible in pulmonary resection for carcinoma.

The American Journal of Suq#ofy

Peripheral Arterial Embolism

Dr. Connett, did any of your patients with delayed embolectomy had peripheral neuropathy after embolectomy? Roy L. Tawes, Jr. (San Mateo, CA): Dr. B&dell noted in his excellent comprehensive review 6 years ago a mortality rate of 25 percent in more than 40 series with amputation rates ranging from 20 to 60 percent, with most being about 40 percent. The results of recent series have improved as we reported recently to the Society for Clinical Vascular Surgery. It is a source of frustration for surgeons that such a simple procedure with the patient under local anesthesia can result in such high amputation and mortality rates. There are several factors that we should consider. First, Dr. Fogarty mentioned the point about different populations in different hospitals. This is one major difference in Dr. Blaisdell’s experience, since I know the type of challenging patients with whom he was dealing. Many came in very late in the course of their disease; some had rigor of the extremity, with irreversible or borderline changes making it difficult to see whether the source was an embolus or thrombosis. Dr. Blaisdell’s treatment with high doses of heparin and selective reconstruction in those patients who survived was very appropriate in that setting. However, in a private hospital, we are more fortunate in seeing patients early. The critical factor is not the time of presentation, but the time the patient loses sensation to light touch or motor function ceases. That is when one has to decide whether or not to operate. Another factor that has not received proper recognition in the literature is the administration of heparin postoperatively. There has been great reluctance to administer heparin postoperatively for fear of wound complications. In the large series that Dr. Fogarty and I reviewed over the past 20 years, our wound complication rate was approximately 22 percent, but only half of these cases required reoperation to evacuate hematomas, to prevent skin edge necrosis, or to prevent wound disruption. Finally, there has been a failure to reoperate early when one has a marginal result to ensure not only ultimate limb survival but satisfactory long-term function. The goal of the vascular surgeon should be to provide a useful and functional limb, not just a viable one. When using a catheter to remove a thrombus, some clot is usually retained. The traumatized intima is also very thrombogenic, and many of these patients are also hypercoaguable. One should not forget that the collateral and venous beds are not treated by the mechanical retrieval of clot. It has also been shown in some recent studies that when heparin is administered postoperatively, there is a definite decrease in arterial emboli as well as a decrease in pulmonary emboli. Heparin buys time for secondary operations. The wound complications are less than expected (22 percent), with only half being clinically significant. We believe this is a fair trade-off.

Vohmu 148, July 1984

F. William Blaisdell (Sacramento, CA): When one analyzes a large series of deaths after acute arterial occlusion, 90 percent are due to thromboembolic complications. These consist of myocardial infarction, stroke, pulmonary embolism, and recurrent embolism. To prevent those types of deaths, heparin treatment is optimal. If one sees a patient early in the ischemic period when the limb is still viable, restoration of circulation may well be appropriate. The key to success if operation is utilized is to continue anticoagulation postoperatively. Death of muscle occurs approximately 3 hours after the onset of severe ischemia, and by 6 to 8 hours after vascular occlusion, there is a significant amount of dead muscle that cannot be revived by operation. It is in this group of patients that the highest mortality rate is found. This relates to reperfusion of dead muscle with washing of toxic products into the systemic circulation. Clinically, this is often associated with the development of a bluish mottling of the involved limb. I advise those of you who use operation for embolism to be aware of this. This patient group in one review of ours had an 80 percent mortality rate. If a limb is viable when first seen, the viability will be increased and not compromised by the administration of heparin, and one has the option of doing an elective operation at a later date. If the limb is not viable, amputation is the treatment of choice. In summary, there are three groups of patients: those who are seen early with a viable limb who can be treated with operation or with heparin anticoagulation, those who have a dead limb that is associated with bluish mottling with firm muscles and who have a high risk for operation and should be treated by amputation, and finally, those who are seen late and who still have a viable limb. These latter patients probably benefit from continued heparin therapy and elective operation at some later date. Mahlon C. Connett (closing): Dr. Fogarty, I appreciate your emphasizing the fact that the age and population distributions are so important. In our series, age was the major prognostic factor regarding outcome, and the mean age of our patients was so much greater than those in some of the other series that we thought it was important. Dr. Winn, we did not analyze our patients with late reconstruction or embolectomy regarding whether or not they had any peripheral neuropathy; however, I am sure that there were some. Dr. Tawes, we appreciate your comments, and we are advocates of heparin. We simply wanted to make the point that we did not treat patients with arterial emboli with heparin only. Our preferred treatment involves the balloon embolectomy catheter with the patient under local anesthesia. Postoperatively, these patients are given heparin and discharged with coumadin. Dr. Blaisdell, we always appreciate your comments, your analysis of the problem of emboli, and your specific and pertinent comments.

19