THE PROPHYLAXIS OF THROMBOEMBOLIC COMPLICATIONS IN SURGERY FOR MITRAL STENOSIS

THE PROPHYLAXIS OF THROMBOEMBOLIC COMPLICATIONS IN SURGERY FOR MITRAL STENOSIS F. G. Uglov, M.D., and L. V. Potashov, M.D., Leningrad,

T

U.S.S.R.

occurring during surgical manipulations on the heart or immediately thereafter, is an extremely hazardous complication of mitral commissurotomy.2' 3> 6> 7>13- "■ 2i>26 Statistics published by the American College of Chest Physicians in 195931 have shown that, in the course of 4,463 eommissurotomies, embolism occurred in 246 patients (5.5 per cent). One hundred and twenty-eight patients died (2.8 per cent). This complication is mostly caused by thrombotic occlusion of the left atrium and its auricle. The incidence of thrombosis ranges from 4.2 to 28 per cent. 1 ' 4 ' 1 3 ' 1 9 ' 2 4 ' 2 6 The occlusion of peripheral vessels could also be the result of valvular calcification, but such mechanism is a rare source of embolization. 10 - 11 - 13 In our practice, thrombosis of the left atrium and its auricle was observed in 90 of 485 patients (18.6 per cent) operated upon for mitral disease. This high incidence of thrombosis is attributed to performing commissurotomy mostly in patients in Stages 4 and 5, according to the classification of A. N. Bakulev. 4 We observed 14 cases of embolism of the peripheral vessels in patients sub­ jected to mitral commissurotomy (Table I ) . HROMBOEMBOLISM,

TABLE I .

INCIDENCE OF EMBOLISM o r

THE PERIPHERAL V E S S E L S I N MITRAL

COMMISSUROTOMY

SOURCES OF E M B O L I S M

TOTAL N O . PATIENTS OPERATED UPON

NO. CASES

485

14

CASES OF EMBOLIZATION |

L E F T ATRIAL THROMBOSIS

PER CENT

NO. CASES

2.9

11

|

CALCIFICATION

PER CENT

NO. CASES

2.27

3

|

PER CENT

0.6

Cerebral embolism occurred in all cases, and 13 of 14 patients died during the first hour or day after the operation. In one patient, symptoms of a dam­ aged cerebral circulation developed, which eventually disappeared under anti­ coagulant therapy. An attempt was made in this study to solve the different problems concerned: (1) to find out the cause of and to improve the methods of diagnosing intracardiac thrombosis in life, (2) to develop methods permitting the reduction of the number of fresh thrombi in the left atrium and the auricle which could be From The Hospital Surgical Clinic of the 1st Pavlov Medical Institute, U.S.S.R. Received for publication Nov. 28, 1961. 408

Leningrad,

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easily displaced, (3) to study the technique of preventing intracardiac thrombotic masses from getting into the blood stream, and (4) the prophylaxis of post­ operative thrombosis of the auricular stump. I. PREOPERATIVE

DIAGNOSIS OF INTRACARDIAC

THROMBOSIS

I N PATIENTS

WITH

MITRAL DISEASE

Intracardiac thrombosis is rarely diagnosed in patients 4 ' 5 ' 1 5 ' 2 0 because of the absence of pathognomonic symptoms. The opportunity to verify such thrombosis during operation has improved its diagnosis considerably. As a result, Petrovsky 24 reported the preoperative recognition of thrombotic occlusion of the left atrium and the auricle in 55 cases. In our practice, great importance is attached to absolute arrhythmia as an indirect evidence of thrombosis in patients with mitral disease. This arrhyth­ mia,22 in combination with the blood stasis resulting from the narrowed atrioventricular orifice, leads to the formation of intra-auricular thrombosis. TABLE I I . T H E INCIDENCE o r THROMBOSIS I N THE L E F T ATRIUM AND I T S AURICLE I N PATIENTS W I T H MITRAL DISEASE W I T H RELATION TO T H E R H Y T H M OF CARDIAC CONTRACTIONS

CHARACTER OF RHYTHM Sinus rhythm Absolute arrhythmia

TOTAL NO. PATIENTS 335 150

NO. PATIENTS WITH THROMBOSIS 7 83

PER CENT 2.1 56.2

In two series of patients with mitral disease associated with absolute ar­ rhythmia, some demonstrated thrombi in the left atrium and its auricle and others did not. Age, sex, duration of the disease, decompensation and arrhythmia, previous history of peripheral embolism, determinants of the blood coagulation system (prothrombin index, clotting time, time of bleeding, platelet count, and fibrinogen concentration), sedimentation rate and number of leukocytes were studied in these patients. An analysis of the data obtained indicated that age and previous history of embolization could be regarded as indirect signs of intra­ cardiac thrombosis in patients with a mitral lesion associated with absolute arrhythmia. All other signs were of no practical value for establishing the diagnosis of left atrial thrombosis. Some writers emphasize the importance of x-ray study in the diagnosis of intracardiac thrombosis. Petrovsky 24 draws attention to the insignificant auricular arch pulsation, rigidity of the auricle and left atrial wall as revealed by the roentgenkymogram. Harris and Levine 15 have emphasized the enlarged left atrium in the presence of thrombosis in it. We have evaluated the x-ray appearance of the heart in two series of our patients, great attention being paid to the third arch of the left contour that usually corresponds to the left atrial auricle. I t was found that in 41.2 per cent of patients the concave arch was evidence of contraction of the thrombosed auricle. I n patients without thrombosis, not a concave but a smooth contour of the third arch was noted in 17.7 per cent of the cases; while in the majority of these patients (54.9 per cent) a prominence of the arch was observed. The

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POTASHOV

latter sign is of relative value in the diagnosis of intracardiac thrombosis, since the displacement of the heart against its axis renders the differentiation of this arch not feasible. It is interesting to note that some patients suffering mitral disease associated with absolute arrhythmia demonstrated thrombosis of the left atrium but others did not. The explanation of this phenomenon presented elsewhere 25 ' 27 seems inade­ quate and we, therefore, concentrated our attention on the relation between the frequency of left atrial thrombosis and the character of mitral disease. The data presented in the literature concerning the estimation of mitral regurgitation as a factor affecting thrombus formation in the atrium are rather con­ tradictory. 8 ' 14>30 With reference to the degree of regurgitation, it was found that 93.9 per cent of our patients with thrombosis of the left atrium and its auricle demonstrated " p u r e " stenosis, or the combined mitral lesion with an insignificant degree of mitral insufficiency. Among patients without thrombosis, marked regurgitation, second and third degree, was observed in 49.1 per cent. It was concluded that marked mitral insufficiency in patients with mitral disease enabled us to exclude thrombosis of the left atrium and its auricle, even in eases of absolute arrhythmia. Taking into consideration all the indirect evidences of left atrial thrombosis, we established the accurate diagnosis of this complication in 44 patients with mitral disease. II.

THE

METHOD

OF PREOPERATIVE

PREPARATION

WITH

P A T I E N T S W I T H MITRAL DISEASE W I T H T H E P U R P O S E OP THROMBOEMBOLIC

ANTICOAGULANTS

IN

PREVENTING

COMPLICATIONS

I t should be noted that fresh, not organized or mixed, thrombi are mostly the source of embolism of the peripheral vessels during the operation or after it (Table I I I ) . TABLE I I I .

T H E RELATIONSHIP B E T W E E N THE OPERATIVE INCIDENCE OP EMBOLISM AND THE PRESENCE OP A F R E S H COMPONENT I N T H E L E F T ATRIAL THROMBUS

T H E APPEARANCE OP THROMBUS

CASES OP THROMBOSIS

CASES OP THROMBOEMBOLISM

PER CENT

Fresh and mixed thrombi Organized thrombi

33 57

10 1

30.3 1.8

It is evident that reduction in the number of fresh thrombi in patients with mitral stenosis would facilitate the performance of mitral commissurotomy and lessen the danger of thromboembolic complications during operation. It could be done in two ways: either by dissolving fresh thrombus or preventing thrombus formation during the period of organization of fresh thrombi. Unfortunately, we have no available medical agents of marked fibrinolytic effect. To a certain extent, heparin possesses this quality but its continuous use in massive dosage prior to operation is productive of dramatic sequelae. Therefore, we first administer anticoagulants of indirect action preoperatively in patients suspected of having intracardiac thrombosis, as approved- by such specialists as D'Allaines and co-writers,2 Ricordeau and Balansa, 26 Beau­ mont and co-writers,5 and others. Some surgeons administer anticoagulants 4 weeks and more before operation, 5 ' 13 ' 26 whereas Strom and Hansen 28 ' 29 begin

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the administration only 5 to 7 days before the operation. From our personal experience, preoperative preparation with anticoagulants should be for not less than 30 days. Investigations, by Kogoy16 indicated that organization of the thrombotic masses in the auricular stump occurs within a month after commissurotomy. We have used anticoagulants in 76 patients in whom intraeardiac thrombosis was suspected in many cases from 30 to 35 days. At the beginning of our practice, anticoagulants of the dicoumarin type were discontinued several days before operation because of fear of their cumula­ tive effect. In their place heparin was used but discontinued 6 to 12 hours prior to the operation. Frequent intramuscular or intravenous injections are un­ desirable during this period; we once observed a severe allergic response to heparin. Our plan of preoperative preparation is as follows: Having determined the basic elements of the blood coagulation system, 0.03 Gm. of Phenilin (2-phenyl-l, 3-indandione) is administered 3 to 4 times a day; 2 days later the dosage is decreased to 0.03 Gm. twice a day. Simultaneously, we maintain control over the prothrombin index and other factors of blood coagula­ tion. We have tried to select the dosage of anticoagulants which would maintain the prothrombin index during treatment within the limits of 30 to 40 per cent. One or 2 days prior to the operation, the Phenilin dosage is decreased and then discontinued. Operation is performed with a prothrombin index of 50 to 60 per cent. We are quite satisfied with the beneficial effect of the Phenilin preparation as it has marked anticoagulative and minimal cumulative effect. No complica­ tions have been noted with its application. Dicoumarin is considered contraindicated in this situation. Although it is evident that the determinations of the prothrombin index, clotting time, fibrinogen values, and platelet count could not fully reflect altera­ tions in the blood coagulation system in the administration of anticoagulants such as Phenilin, we believe that control of these determinants is sufficient to provide safety in anticoagulant therapy in surgical practice. III. T H E R E S U L T S OP T H E PREOPERATIVE PREPARATION W I T H

ANTICOAGULANTS

The degree of reduction, both in the incidence of a fresh component in thrombi and in the operative thromboembolie complications, was regarded as a criterion of the efficacy of continuous preoperative preparation in patients suspected of intraeardiac thrombosis. Two groups of patients were taken for comparison. The first group was comprised of 78 patients with mitral disease in whom thrombosis of the left atrium and the auricle was suspected but they were not treated with anticoagulants before the operation. The second group consisted of 76 patients, also suspected of intraeardiac thrombosis. These pa­ tients were continuously treated with anticoagulants during the preoperative period. The results for comparison of the two groups of patients are presented in Table IV.

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TABLE IV. INCIDENCE OF THEOMBOEMBOLIC COMPLICATIONS I N MITRAL COMMISSDROTOMY P A T I E N T S TREATED AND N O T TREATED W I T H ANTICOAGULANTS PREOPERATIVELY (154 PATIENTS) THROMBI WITH A FRESH COMPONENT

ORGANIZED THROMBI

IN

EMBOLISM WITH A PIECE OF A THROMBUS

NO. P A T I E N T S SUSPECTED OF THROMBOSIS OF T H E L E F T A T R I U M A N D I T S AURICLE

TOTAL NO. CASES OF DETECTED THROMBI

NO. CASES

PER CENT

NO. CASES

PER CENT

NO. CASES

PER CENT

Not treated with anticoagu­ lants (-78)

39

27

69.2

12

30.8

8

10.3

Treated (-76)

44

3

6.8

41

93.2

1

1.3

with

anticoagulants

In 2 cases, not included in this table, operative cerebral embolism occurred. Left atrial thrombosis was not suspected before operation, but during the opera­ tion the impaired rhythm of cardiac contractions was noted. At autopsy in both cases, fresh thrombi were found that were the source of the acute cerebral occlusion. Our experience with the preoperative anticoagulant therapy in patients in whom intracardiac thrombosis was suspected indicates a tenfold decrease in the incidence of the fresh component in thrombus a measure which we believe greatly diminishes the risk of embolization during operation. The only case of cerebral embolism in the group of patients treated with anticoagulants occurred in a patient in whom a mixed thrombus was detected. This failure probably was due to the inadequate reduction of the prothrombin index during the administration of Phenilin. IV. THK TECHNIQUE OF PREVENTING THE THROMBOTIC MASSES FROM GETTING INTO THE BLOOD STREAM

The danger of mobilizing thrombotic masses during the operation with subsequent embolism of the peripheral vessels stimulated the development of methods to prevent this hazardous complication in mitral commissurotomv 2 ' 3 ' 6 " 1 0 ' 1 2 ' 1 8 ' 2 1 > 23 ' 24 We use the following technique in thrombosis of the left atrium and its auricle. The clamp is not applied to the auricle. If the auricle is contracted a purse-string suture is placed about its base or atrial wall. An incision is made through which the blood is splashed out. "With the detection of fresh thrombi the procedure should be repeated. What we do next depends on the character of the thrombus localization. Fresh, not organized, thrombi are removed by a finger or by instrument. During thrombectomy the carotid arteries are com­ pressed. If a dense and flat thrombus is detected, which presents no obstacle for commissurotomy, it is not necessary to remove it. During thrombectomy an at'empt is made to resect the auricular portion to which thrombus was at­ tached. It should be emphasized that thrombectomy was performed in 27 of 44 patients treated with anticoagulants prior to operation, whereas, in patients without anticoagulant therapy, thrombectomy was necessary in all instances.

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Recently some surgeons, when they suspect thrombosis of the left atrium and its auricle, have been performing mitral commissurotomy through the right-sided approach. We have used this kind of approach but twice. We believe that mitral commissurotomy through the intra-atrial septum is potentially dangerous in the mobilization of fresh thrombus if the latter invades the atrium. In this case, therefore, preoperative preparation with anticoagulants seems also quite reasonable. V. T H E P R O P H Y L A X I S OP THROMBOEMBOLIC COMPLICATIONS AFTER MITRAL COMMISSUROTOMY

The risk of distal embolization is always present in patients with absolute arrhythmia in whom thrombosis of the left atrium and the auricle was detected during the operation, and even in those who were thrombectomized. In such patients the administration of anticoagulants in the immediate postoperative period is strongly advocated. 12 ' 24 ' 29 Forty-one of our patients were given anti­ coagulants postoperatively for an average duration of 16 days. In some cases it was continued for 2 months. Not infrequently Phenilin was administered on the first postoperative day (28 cases). In 6 cases, the combination of heparin and Phenilin was used, in 5 cases only heparin, in one case Phenilin and Pelentan, and in one case dicoumarin. It should be noted that sometimes the administration of heparin for some hours after the operation was accompanied by an increased discharge of blood from the pleural cavity. In 2 cases, hemorrhage was a concomitant cause of death. No complications were encountered after the postoperative use of Phenilin. It is noteworthy that, at autopsy, fresh thrombi in the auricle and atrium were found in the majority of patients not treated with anticoagulants, either before or after the operation. Namely, they were found in 10 patients who died from thromboembolism of the cerebral vessels. Postmortem studies of patients to whom anticoagulants were administered showed almost an entire absence of fresh clots. SUMMARY

1. Fresh thrombi in the left atrium and the auricle are extremely dangerous for they are frequently responsible for the development of thromboembolic com­ plications in mitral valve surgery. 2. The diagnosis of " p u r e " mitral stenosis or stenosis with slight mitral insufficiency in patients with absolute arrhythmia suggests the possibility also of thrombosis of the left atrium and its auricle. This possibility seems to be more probable if the patient is over 30 years of age and has a previous history of embolism of the peripheral vessels, and a concave third arch of the left heart contour as revealed by x-ray study. 3. One month's preoperative anticoagulant therapy in patients in whom intracardiac thrombosis is suspected provides a considerable reduction in the number of fresh thrombi and lessens the danger of thromboembolic complica­ tions during commissurotomy.

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4. Proper surgical technique and the use of anticoagulants postoperatively are also of great significance in the prophylaxis of thromboembolic complications in the operative treatment of patients with mitral disease. REFERENCES

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