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Surgical management of massive pulmonary embolism
Surgical management of massive pulmonary embolism Between 1972 and 1976, 24 patients have been treated by open pulmonary embolectomy with the aid of cardiopulmonary bypass (CPB). In 17 (71 percent) acute pulmonary embolism occurred 3 to 60 days after a surgical procedure. The remaining seven (29 percent) patients had chronic medical diseases. The interval between clinical manifestation of acute pulmonary embolism and the performance of open embolectomy ranged from 8 to 36 hours. The definitive diagnosis in all patients was made by pulmonary arteriography. Candidates for pulmonary embolectomy were selected by assessment of hemodynamic studies: shock, arterial P0 21ess than 65 mm. Hg, acidosis, pulmonary artery pressure higher than 20 to 30 mm. Hg, and central venous pressure elevated (patients in Class III or IV according to the Greenfield classification). The definitive indication for embolectomy was occlusion of the main pulmonary artery of more than 50 percent as well as occlusion of the right or left pulmonary artery. Of the seven patients operated upon between 1973 and 1974, three (43 percent) died in the early postoperative period. Between 1975 and 1976 the operative mortality rate in 17 patients was 23 percent (four patients). Our results show that prompt diagnosis of acute massive pulmonary embolism and better selection of patients may improve significantly the survival rate after open pulmonary embolectomy with C PB.
A. Tschirkov, M.D., E. Krause, M.D., O. Elert, M.D., and P. Satter, M.D., Frankfurt, West Germany
Massive pulmonary embolism is usually associated with systemic hypotension, overloading of the right side of the heart, or cardiac arrest. This condition appears most often when the degree of thromboembolic occlusion of the pulmonary arterial tree is greater than 50 percent.I" The course and prognosis of massive pulmonary embolism may vary significantly. In many patients, the hemodynamic effect of the embolus is so disasterous that cardiac arrest or cardiogenic shock cannot be managed successfully by intensive resuscitative measures. These patients die within 1 hour after the onset of symptoms.": 5 A Trendelenburg transthoracic embolectomy" 7 can be attempted, but the operative mortality rate of this surgical intervention is enormously high-greater than 95 percent. 8 In about 25 percent of patients with massive embolism, cardiac arrest or cardiogenic shock can be successfully managed by resuscitation. These patients live longer than 2 hours after the onset of acute symptoms." From the Deparlment of Thoracic and Cardiovascular Surgery, Johann Wolfgang Goethe-Universitat, Frankfurt/Main, West Germany. Received for publication Aug. 17, 1977. Accepted for publication Nov. 22, 1977.
730
As a result, a significant number of these patients can be saved if the diagnosis can be confirmed by arteriography and an open embolectomy rapidly performed. In this paper we will discuss our experience with the diagnostic evaluation and operative management of 24 patients with acute massive pulmonary embolism who lived longer than 2 hours after the onset of acute symptoms. Patients and methods During the period from 1972 to 1976, we performed open pulmonary embolectomy with the aid of cardiopulmonary bypass (CPB) in 24 patients. Of these patients 13 were men and II women. Their ages ranged from 21 to 69 years (Table I). The interval between clinical manifestation of acute pulmonary embolism and the performance of open embolectomy was from 8 to 36 hours. In all patients, the definitive diagnosis was made by pulmonary arteriography. Candidates for pulmonary embolectomy were selected by assessment of clinical and angiographic findings. The important findings are summarized in Table II. Sixteen of the patients suffered from dyspnea and collapse. The remaining eight had symptoms of increasing shock (systemic systolic blood pressure less than 90 mm. Hg).
0022-5223/78/0575-0730$00.40/0 © 1978 The C. V. Mosby Co.
Volume 75 Number 5 May, 1978
Massive pulmonary embolism
73 I
Table IA. Open pulmonary embolectomy with cardiopulmonary bypass (1973-1976) No. of patient s
24
Sex Male Female Age Caus e of emb olism Previous operation Chronic medi cal disease Interval : Previous operation to pulmonary thromboembolism Interval : Clinical manifestation to ernbolectomy
13 II 2 1-69 yr. 14
7 3-60 days 8-36 hr.
Table lB. Deaths (1973-/976) Total deaths Interval
No. of operated patients
No.
1973-1974 1975-1976
7 17
3 4
I
% 43 23
Operative deaths No.
I
% 14
6
The hemodynamic measurements showed elevated central venous pressure and elevated pulmonary artery pressure (from 20 to 40 mm. Hg) in all patients. Four of the 24 patients had a sudden cardiac arrest at the introduction of anesthesia and had to be resuscitated by means of external and intrathoracic cardiac massage or CPB prior to embolectomy. Pulmonary arteriography demonstrated in all patients a thromboembolic occlusion of the pulmonary arterial tree of more than 50 percent. Thirteen patients had clinical signs of deep venous thrombosis of the legs, but only in six patients was this diagnosis established by phlebography. The values for serum lactic dehydrogenose, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase , and bilirubin were elevated in only eight patients . The electrocardiogram in 17 patients (71 percent ) showed evidence of an increased pulmonary second sound and nonspecific T -wave changes, right or left axis deviation, and low-voltage QRS. There was no correlation between elevated right ventricular enddiastolic pre ssure and the degree of hypoxemia .
Surgical technique A median sternotomy was performed, and CPB was established by single cannulation of the right atrium or both venae cavae. In cases in which both venae cavae were cannulated, a vent was inserted into the right atrium to aspirate the blood of the coronary sinus after the venae cavae were occluded . The large central
Fig. 1. Pulmonary arteriogram of a 62-year-old woman with acute massive pulmonary emboli sm . There is a total occlusion of the right pulmonary artery and of the superior branch of the left pulmona ry artery .
thrombi were easily removed with forceps through a longitudinal incision in the main pulmonary artery. The pulmonary artery was occluded at the base only in the patients who had single cannulation of the right atrium . If peripheral thrombi were present , the mediastinal pleura was inci sed and both lungs were massaged to drive the thrombi to the main pulmonary artery. Most of the peripheral thrombi could be successfully removed with Fogarty and aspirating catheters (Fig s. I and 2). To prevent further embolic episodes, we performed intravenous interruption of the inferior vena cava by the umbrella-like intracaval device. 10 The vena cava filter is one of the most effective methods of preventing recurrent pulmonary embolism. 10. 11 At the end of CPB a Mobin-Uddin umbrella, attached to a cardiac catheter, was introduced under fluoro scopi c control via the right atrial appendage into the inferior vena cava and advanced to a position just above the confluence of the iliac vein . The position of the umbrella was ascertained by means of a postoperative roentgenogram of the abdomen . Intravenous interruption of the inferior vena ca va was attempted in 13 patients but wa s done successfully in only eight patients (6 1 percent). Results One of the seven patients who underwent open pulmonary embolectomy during the period 1973 to 1974 died on the table (Table I) from irreversible damage to the myocardium. Prior to embolectomy, this patient had an acute cardiac arrest and wa s resuscitated by
The Journal of
732
Tschirkov et al.
Thoracic and Cardiovascular Surgery
1' ;111 "
Fig. 2. Thrombiextractedfrom the pulmonary arteryof the patient whose pulmonary arteriogram is illustrated in Fig. I. The woman survived open pulmonary embolectomy.
Table II. Summary of preoperative clinical, hemodynamic, and angiographic findings from 24 patients with massive pulmonary embolism Clinical status No. of patients Survived
Female Male Died Female Male
Dyspnea, collapse
I Shock, dyspnea
Hemodynamic indications *
Resuscitation for cardiac arrestt
PA occlusion >50%
17
13
4
17
2
17
7
3
4
7
2
7
9 8 2
5
Legend: PA, Pulmonary artery, *The hemodynamic indications were tachycardia, elevated central venous pressure, and pulmonary artery pressure between 15 and 35 mrn. Hg. tThese patients had a cardiac arrest and were resuscitated prior to embolectomy by cardiopulmonary bypass or external cardiac massage.
external cardiac massage and ePB. Another two of the seven patients died on the third and fourth postoperative days, respectively, of intractable right ventricular failure. The remaining four patients (57 percent) survived the open embolectomy and were discharged in satisfactory clinical and hemodynamic status. Thirteen of the 17 patients undergoing open pulmonary embolectomy during the period 1974 to 1976 survived the operation and had uneventful postoperative courses. The mortality rate in this group of patients was 23 percent (four patients). There was one operative death: The patient had a cardiac arrest at the beginning of anesthesia and could not be taken off ePB because of irreversible failure of the left ventricle. Three patients died in the early postoperative phase as a result of increasing cardiogenic shock and pulmonary edema. Two of the 17 patients who survived open embolectomy had a
cardiac arrest prior to operation and were successfully treated by external cardiac massage and ePB. In all surviving patients, anticoagulation therapy was maintained for 6 months following the operation. Intermittent compression of the legs was recommended to prevent deep vein thrombosis.V Discussion Two of the primary determinants of the outcome in patients with acute massive pulmonary embolism are prompt confirmation of the diagnosis and determination of the extent of pulmonary thromboembolism by pulmonary arteriography, so that candidates for open embolectomy can be identified. The indications for open embolectomy usually are based on the hemodynamic measurements and findings from pulmonary arteriography, in agreement with the criteria reported by Sasah-
Volume 75
Massive pulmonary embolism
Number 5 May, 1978
ara," Greenfield;" and Limbourg and colleagues: 15 systolic systemic pressure less than 90 mm. Hg; elevated pulmonary artery pressure, from 22 to 40 mm. Hg; arterial Poj less than 60 mm. Hg; pulmonary artery occlusion of greater than 50 percent. It is generally agreed that an elevation of the mean right ventricular pressure above 40 mm. Hg should arouse suspicion of chronic recurrent embolization. The statement of del Guericio.!" that elevation of mean right ventricular pressure above 22 mm. Hg indicates a very poor prognosis, could not be verified by our results. The mortality rate after operative treatment of pulmonary embolism remains high, ranging from 24 percent' to 93 percent;'? and the opinions regarding the indication for embolectomy diverge widely, some authors believing that surgery is never indicated'" and others advocating prophylactic embolectomy. I However, because of our experience, we believe that open pulmonary embolectomy with CPB provides the best chance for survival in patients with massive pulmonary embolism. The sole alternative to open embolectomy seems to be transvenous pulmonary embolectomy with a catheter device." In most of our patients undergoing open pulmonary embolectomy, the decision to operate was made later than 12 hours after the acute onset of symptoms. This fact indicates that there is a real possibility of decreasing the mortality rate significantly below the 23 percent registered in our patients who were operated upon during the period 1975 to 1976. In other words, if the decision to operate is made as soon as the diagnosis is established by arteriography, a significant number of patients with massive pulmonary embolism may be saved. The statement that open pulmonary embolectomy should be attempted if other nonoperative treatments have failed cannot be justified. There is no reason for hesitation if the evidence of cardiogenic shock is present and the thromboembolic occlusion of the pulmonary artery is confirmed by arteriography. An optimal collaboration between cardioradiologists and surgeons might contribute enormously to the indication for open pulmonary embolectomy. The question of when the "Rubicon" is reached remains critical in patients who have thromboembolic occlusion of the pulmonary artery of more than 50 percent but survive long enough without rapid deterioration. The fate of these patients is uncertain.
733
REFERENCES
2
3 4
5 6
7 8
9
10
II
12
13 14 15
16
17 18
19
Berger RL: Pulmonary embolectomy with preoperative circulatory support. Ann Thorac Surg 16:217, 1973 Greenfield LJ, Bruce TA, Nichols NB: Transvenous pulmonary embolectomy by catheter device. Ann Surg 174:881, 1971 Tumier E, Hill JD, Kerth WJ, Gerbode F: Massive pulmonary embolism. Am J Surg 125:611, 1973 Crane C, Hartsuck J, Birtch A, Couch NP, Zollinger R Jr, Matloff J, Dalen J, Dexter L: The management of major pulmonary embolism. Surg Gynecol Obstet 128:27, 1969 Dalen JE, Alpert JS: Natural history of pulmonary embolism. Progr Cardiovasc Dis 17:259, 1975 Kirschner M: Ein durch die Trendelenburgsche Operation geheilter Fall von Embolie der Art. pulmonalis. Arch Klin Chir 133:312, 1924 Trendelenburg F: Ueber die operative Behandlung der Embolie der Lungenarterie. Arch Klin Chir86:686, 1908 Donaldson GA, Williams C, Scannell JG, et al: Reappraisal of the application of the Trendelenburg operation to massive fatal embolism. N Engl J Med 268: 171, 1963 Rosenberg DML, Pearce C, McNulty J: Surgical treatment of pulmonary embolism. J THoRAc CARDIOVASC SURG 47:1,1964 Mobin-Uddin K, Bolooki H, Jude JR: Intravenous caval interruption for pulmonary embolism in cardiac disease. Circulation 41, 42:Suppl 2152, 1970 Schlosser V, Spillner G, Kaiser W: Prevention of pulmonary embolism by inferior vena cava filters. Results in 62 cases. World J Surg 1:113, 1977 Cotton LT, Roberts VC: The prevention of deep vein thrombosis, with particular reference to mechanical methods of prevention. Surgery 81:228, 1977 Sasahara AA: Pulmonary vascular responses to thromboembolism. Mod Cone Cardiovasc Dis 36:55, 1967 Greenfield LJ: Pulmonary embolism. Diagnosis and management. Curr Probl Surg 13: 17, 1976 Limbourg P, Just H, Lang KF, Satter P: Ergebnisse der Embolektomie bei massiver Lungenembolie. Dtsch. Med. Wochenschr 102:649, 1977 del Guericio LRM, Cohn JD, Feins, NR, Coomaraswamy RP, Montie L: Pulmonary embolism shock. Physiologic basis of a bedside screening test. JAMA 196:71, 1966 Scannell JG: The surgical management of acute massive pulmonary embolism. Progr Cardiovasc Dis 9:488, 1967 Sautter RD, Myers WO, Ray JF III, Wenzel FJ: Pulmonary embolectomy. Review and current status. Progr Cardiovasc Dis 17:371, 1975 Sharp EH: Pulmonary embolectomy. Successful removal of a massive pulmonary embolus with support of cardiopulmonary bypass. Case report. Ann Surg 156: I, 1962
A. Tschirkov, M.D., E. Krause, M.D., O. Elert, M.D., and P. Satter, M.D., Frankfurt, West Germany
Massive pulmonary embolism is usually associated with systemic hypotension, overloading of the right side of the heart, or cardiac arrest. This condition appears most often when the degree of thromboembolic occlusion of the pulmonary arterial tree is greater than 50 percent.I" The course and prognosis of massive pulmonary embolism may vary significantly. In many patients, the hemodynamic effect of the embolus is so disasterous that cardiac arrest or cardiogenic shock cannot be managed successfully by intensive resuscitative measures. These patients die within 1 hour after the onset of symptoms.": 5 A Trendelenburg transthoracic embolectomy" 7 can be attempted, but the operative mortality rate of this surgical intervention is enormously high-greater than 95 percent. 8 In about 25 percent of patients with massive embolism, cardiac arrest or cardiogenic shock can be successfully managed by resuscitation. These patients live longer than 2 hours after the onset of acute symptoms." From the Deparlment of Thoracic and Cardiovascular Surgery, Johann Wolfgang Goethe-Universitat, Frankfurt/Main, West Germany. Received for publication Aug. 17, 1977. Accepted for publication Nov. 22, 1977.
730
As a result, a significant number of these patients can be saved if the diagnosis can be confirmed by arteriography and an open embolectomy rapidly performed. In this paper we will discuss our experience with the diagnostic evaluation and operative management of 24 patients with acute massive pulmonary embolism who lived longer than 2 hours after the onset of acute symptoms. Patients and methods During the period from 1972 to 1976, we performed open pulmonary embolectomy with the aid of cardiopulmonary bypass (CPB) in 24 patients. Of these patients 13 were men and II women. Their ages ranged from 21 to 69 years (Table I). The interval between clinical manifestation of acute pulmonary embolism and the performance of open embolectomy was from 8 to 36 hours. In all patients, the definitive diagnosis was made by pulmonary arteriography. Candidates for pulmonary embolectomy were selected by assessment of clinical and angiographic findings. The important findings are summarized in Table II. Sixteen of the patients suffered from dyspnea and collapse. The remaining eight had symptoms of increasing shock (systemic systolic blood pressure less than 90 mm. Hg).
0022-5223/78/0575-0730$00.40/0 © 1978 The C. V. Mosby Co.
Volume 75 Number 5 May, 1978
Massive pulmonary embolism
73 I
Table IA. Open pulmonary embolectomy with cardiopulmonary bypass (1973-1976) No. of patient s
24
Sex Male Female Age Caus e of emb olism Previous operation Chronic medi cal disease Interval : Previous operation to pulmonary thromboembolism Interval : Clinical manifestation to ernbolectomy
13 II 2 1-69 yr. 14
7 3-60 days 8-36 hr.
Table lB. Deaths (1973-/976) Total deaths Interval
No. of operated patients
No.
1973-1974 1975-1976
7 17
3 4
I
% 43 23
Operative deaths No.
I
% 14
6
The hemodynamic measurements showed elevated central venous pressure and elevated pulmonary artery pressure (from 20 to 40 mm. Hg) in all patients. Four of the 24 patients had a sudden cardiac arrest at the introduction of anesthesia and had to be resuscitated by means of external and intrathoracic cardiac massage or CPB prior to embolectomy. Pulmonary arteriography demonstrated in all patients a thromboembolic occlusion of the pulmonary arterial tree of more than 50 percent. Thirteen patients had clinical signs of deep venous thrombosis of the legs, but only in six patients was this diagnosis established by phlebography. The values for serum lactic dehydrogenose, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase , and bilirubin were elevated in only eight patients . The electrocardiogram in 17 patients (71 percent ) showed evidence of an increased pulmonary second sound and nonspecific T -wave changes, right or left axis deviation, and low-voltage QRS. There was no correlation between elevated right ventricular enddiastolic pre ssure and the degree of hypoxemia .
Surgical technique A median sternotomy was performed, and CPB was established by single cannulation of the right atrium or both venae cavae. In cases in which both venae cavae were cannulated, a vent was inserted into the right atrium to aspirate the blood of the coronary sinus after the venae cavae were occluded . The large central
Fig. 1. Pulmonary arteriogram of a 62-year-old woman with acute massive pulmonary emboli sm . There is a total occlusion of the right pulmonary artery and of the superior branch of the left pulmona ry artery .
thrombi were easily removed with forceps through a longitudinal incision in the main pulmonary artery. The pulmonary artery was occluded at the base only in the patients who had single cannulation of the right atrium . If peripheral thrombi were present , the mediastinal pleura was inci sed and both lungs were massaged to drive the thrombi to the main pulmonary artery. Most of the peripheral thrombi could be successfully removed with Fogarty and aspirating catheters (Fig s. I and 2). To prevent further embolic episodes, we performed intravenous interruption of the inferior vena cava by the umbrella-like intracaval device. 10 The vena cava filter is one of the most effective methods of preventing recurrent pulmonary embolism. 10. 11 At the end of CPB a Mobin-Uddin umbrella, attached to a cardiac catheter, was introduced under fluoro scopi c control via the right atrial appendage into the inferior vena cava and advanced to a position just above the confluence of the iliac vein . The position of the umbrella was ascertained by means of a postoperative roentgenogram of the abdomen . Intravenous interruption of the inferior vena ca va was attempted in 13 patients but wa s done successfully in only eight patients (6 1 percent). Results One of the seven patients who underwent open pulmonary embolectomy during the period 1973 to 1974 died on the table (Table I) from irreversible damage to the myocardium. Prior to embolectomy, this patient had an acute cardiac arrest and wa s resuscitated by
The Journal of
732
Tschirkov et al.
Thoracic and Cardiovascular Surgery
1' ;111 "
Fig. 2. Thrombiextractedfrom the pulmonary arteryof the patient whose pulmonary arteriogram is illustrated in Fig. I. The woman survived open pulmonary embolectomy.
Table II. Summary of preoperative clinical, hemodynamic, and angiographic findings from 24 patients with massive pulmonary embolism Clinical status No. of patients Survived
Female Male Died Female Male
Dyspnea, collapse
I Shock, dyspnea
Hemodynamic indications *
Resuscitation for cardiac arrestt
PA occlusion >50%
17
13
4
17
2
17
7
3
4
7
2
7
9 8 2
5
Legend: PA, Pulmonary artery, *The hemodynamic indications were tachycardia, elevated central venous pressure, and pulmonary artery pressure between 15 and 35 mrn. Hg. tThese patients had a cardiac arrest and were resuscitated prior to embolectomy by cardiopulmonary bypass or external cardiac massage.
external cardiac massage and ePB. Another two of the seven patients died on the third and fourth postoperative days, respectively, of intractable right ventricular failure. The remaining four patients (57 percent) survived the open embolectomy and were discharged in satisfactory clinical and hemodynamic status. Thirteen of the 17 patients undergoing open pulmonary embolectomy during the period 1974 to 1976 survived the operation and had uneventful postoperative courses. The mortality rate in this group of patients was 23 percent (four patients). There was one operative death: The patient had a cardiac arrest at the beginning of anesthesia and could not be taken off ePB because of irreversible failure of the left ventricle. Three patients died in the early postoperative phase as a result of increasing cardiogenic shock and pulmonary edema. Two of the 17 patients who survived open embolectomy had a
cardiac arrest prior to operation and were successfully treated by external cardiac massage and ePB. In all surviving patients, anticoagulation therapy was maintained for 6 months following the operation. Intermittent compression of the legs was recommended to prevent deep vein thrombosis.V Discussion Two of the primary determinants of the outcome in patients with acute massive pulmonary embolism are prompt confirmation of the diagnosis and determination of the extent of pulmonary thromboembolism by pulmonary arteriography, so that candidates for open embolectomy can be identified. The indications for open embolectomy usually are based on the hemodynamic measurements and findings from pulmonary arteriography, in agreement with the criteria reported by Sasah-
Volume 75
Massive pulmonary embolism
Number 5 May, 1978
ara," Greenfield;" and Limbourg and colleagues: 15 systolic systemic pressure less than 90 mm. Hg; elevated pulmonary artery pressure, from 22 to 40 mm. Hg; arterial Poj less than 60 mm. Hg; pulmonary artery occlusion of greater than 50 percent. It is generally agreed that an elevation of the mean right ventricular pressure above 40 mm. Hg should arouse suspicion of chronic recurrent embolization. The statement of del Guericio.!" that elevation of mean right ventricular pressure above 22 mm. Hg indicates a very poor prognosis, could not be verified by our results. The mortality rate after operative treatment of pulmonary embolism remains high, ranging from 24 percent' to 93 percent;'? and the opinions regarding the indication for embolectomy diverge widely, some authors believing that surgery is never indicated'" and others advocating prophylactic embolectomy. I However, because of our experience, we believe that open pulmonary embolectomy with CPB provides the best chance for survival in patients with massive pulmonary embolism. The sole alternative to open embolectomy seems to be transvenous pulmonary embolectomy with a catheter device." In most of our patients undergoing open pulmonary embolectomy, the decision to operate was made later than 12 hours after the acute onset of symptoms. This fact indicates that there is a real possibility of decreasing the mortality rate significantly below the 23 percent registered in our patients who were operated upon during the period 1975 to 1976. In other words, if the decision to operate is made as soon as the diagnosis is established by arteriography, a significant number of patients with massive pulmonary embolism may be saved. The statement that open pulmonary embolectomy should be attempted if other nonoperative treatments have failed cannot be justified. There is no reason for hesitation if the evidence of cardiogenic shock is present and the thromboembolic occlusion of the pulmonary artery is confirmed by arteriography. An optimal collaboration between cardioradiologists and surgeons might contribute enormously to the indication for open pulmonary embolectomy. The question of when the "Rubicon" is reached remains critical in patients who have thromboembolic occlusion of the pulmonary artery of more than 50 percent but survive long enough without rapid deterioration. The fate of these patients is uncertain.
733
REFERENCES
2
3 4
5 6
7 8
9
10
II
12
13 14 15
16
17 18
19
Berger RL: Pulmonary embolectomy with preoperative circulatory support. Ann Thorac Surg 16:217, 1973 Greenfield LJ, Bruce TA, Nichols NB: Transvenous pulmonary embolectomy by catheter device. Ann Surg 174:881, 1971 Tumier E, Hill JD, Kerth WJ, Gerbode F: Massive pulmonary embolism. Am J Surg 125:611, 1973 Crane C, Hartsuck J, Birtch A, Couch NP, Zollinger R Jr, Matloff J, Dalen J, Dexter L: The management of major pulmonary embolism. Surg Gynecol Obstet 128:27, 1969 Dalen JE, Alpert JS: Natural history of pulmonary embolism. Progr Cardiovasc Dis 17:259, 1975 Kirschner M: Ein durch die Trendelenburgsche Operation geheilter Fall von Embolie der Art. pulmonalis. Arch Klin Chir 133:312, 1924 Trendelenburg F: Ueber die operative Behandlung der Embolie der Lungenarterie. Arch Klin Chir86:686, 1908 Donaldson GA, Williams C, Scannell JG, et al: Reappraisal of the application of the Trendelenburg operation to massive fatal embolism. N Engl J Med 268: 171, 1963 Rosenberg DML, Pearce C, McNulty J: Surgical treatment of pulmonary embolism. J THoRAc CARDIOVASC SURG 47:1,1964 Mobin-Uddin K, Bolooki H, Jude JR: Intravenous caval interruption for pulmonary embolism in cardiac disease. Circulation 41, 42:Suppl 2152, 1970 Schlosser V, Spillner G, Kaiser W: Prevention of pulmonary embolism by inferior vena cava filters. Results in 62 cases. World J Surg 1:113, 1977 Cotton LT, Roberts VC: The prevention of deep vein thrombosis, with particular reference to mechanical methods of prevention. Surgery 81:228, 1977 Sasahara AA: Pulmonary vascular responses to thromboembolism. Mod Cone Cardiovasc Dis 36:55, 1967 Greenfield LJ: Pulmonary embolism. Diagnosis and management. Curr Probl Surg 13: 17, 1976 Limbourg P, Just H, Lang KF, Satter P: Ergebnisse der Embolektomie bei massiver Lungenembolie. Dtsch. Med. Wochenschr 102:649, 1977 del Guericio LRM, Cohn JD, Feins, NR, Coomaraswamy RP, Montie L: Pulmonary embolism shock. Physiologic basis of a bedside screening test. JAMA 196:71, 1966 Scannell JG: The surgical management of acute massive pulmonary embolism. Progr Cardiovasc Dis 9:488, 1967 Sautter RD, Myers WO, Ray JF III, Wenzel FJ: Pulmonary embolectomy. Review and current status. Progr Cardiovasc Dis 17:371, 1975 Sharp EH: Pulmonary embolectomy. Successful removal of a massive pulmonary embolus with support of cardiopulmonary bypass. Case report. Ann Surg 156: I, 1962