Surgical Treatment of Congenital Heart Disease with Special Reference to the Application of Hypothermia Kazumi Taguchi, M.D., Kenji Fujimura, M.D., Keizo Kato, M.D., Akio Suzuki, M.D., Masaru Hirao, M.D., Hiroaki Shiote, M.D., Eishi Kato, M.D., Mitsuru Nakagaki, M.D., Shigenobu Kado, M.D., Takaaki Mochizuki, M.D., a n d Keiichi Takamura, M.D. ABSTRACT This report presents the results of operation for congenital heart disease using two different methods of hypothermia:(1)Immersion hypothermia alone. Of the 782 patients who underwent open-heart operations using this method the results were good in patients whose intracardiac surgical repair took less than one hour (average mortality rate, 5.6%). (2) Rapid extracorporeal cooling. Of the 269 patients with congenital heart diseases such as ventricular septa1 defect, tetralogy of Fallot, or atrioventricular canal with low cardiac reserve who underwent operation with mild to moderate hypothermia utilizing rapid extracorporeal cooling, the mortality was 11.2%. In the 151 patients with more serious defects, including the extreme form of tetralogy of Fallot, single ventricle, and truncus arteriosus, who underwent open-heart operations with deep hypothermia utilizing extracorporeal cooling, the mortality rate was 15.2%.

Since 1950, when Bigelow and his associates [5] experimentally demonstrated the usefulness of deep hypothermia, many reports [16] have been published which include considerable clinical experience. Gradually, however, the application of deep hypothermia by surface cooling as well as extracorporeal blood cooling in open-heart operations [15] was abolished with the advent of the pump oxygenator [4]. With advances in operations for congenital heart disease, it gradually became apparent that repair of complicated cardiac anomalies should be performed during early infancy, and reports From the Department of Surgery, Hiroshima University School of Medicine, and the Department of Cardiac Surgery, Hiroshima Citizens Hospital, Hiroshima, Japan. Accepted for publication July 11, 1975. Address reprint requests to Dr. Taguchi, Department of Surgery, Hiroshima University Hospital, 1-2-3 Kasumi, Hiroshima, Japan 734.

296

describing the pathological complications involved in applying the pump oxygenator to infants began to appear in the literature [2,6,8]. In this light, hypothermia has been reevaluated by several groups [lo, 111, and workers at Kyoto University have established a method of deep hypothermia using cardiopulmonary bypass as an aid that is currently attracting much attention [9, 121. At the Department of Surgery, Hiroshima University School of Medicine, and the Department of Cardiac Surgery, Hiroshima Citizens Hospital, from January, 1965, to July, 1974, hypothermia by the immersion method or by rapid extracorporeal cooling was applied to 1,202patients with congenital heart disease. The purpose of this report is to evaluate the application of hypothermia in this series of patients.

Materials and Methods Among patients with congenital heart disease undergoing surgical repair, 782 were operated on using immersion hypothermia and 420 had rapid extracorporeal cooling (Table 1).The age of these patients ranged from 1 month to 48 years. As premedication, soya-lecithin and vitamin E were given orally at a dose of 0.5 gm per kilogram of body weight per day and 100 to 200 mg per day, respectively [9]. The patients were sedated the night before and 2% hours prior to operation; and 11/2 hours, 1 hour, and 30 minutes before the operation Vesprin (0.4 mglkg), promethazine (1.0 mglkg), Pethilorphane (1.0 mglkg), and atropine (0.1 mglkg) were given in divided doses. Im mersio n Hypo th erm ia Candidates for immersion hypothermia were selected from among the patients with common congenital heart diseases with lower operative

297 Taguchi et al: Congenital Heart Disease and Hypothermia

Table 1 . Congenital Heart Diseases Repaired or Palliated under Hypothermia Method of Hypothermia Immersion

Lesion VSD ASD TF VSD, ASD ASD, PS VSD, PS PS Rupt Valsalva ECD TGV APVR PS, ASD A-V defect Coronary fistula Double-outlet RV VSD, coarctation Other

Total Mild to moderate, utilizing rapid extracorporeal cooling

Total Series total

363 198

54 33 32 28 23 15 14 3 5 2 2 2 1 1 6

782 VSD TF ECD PS Congenital valve diseases_ VSD, A1 Rupt Valsalva ASD Other

Total Deep, utilizing rapid extracorporeal cooling

No. of

Patients

TF TGV Single ventricle Single atrium, ECD Double-outlet RV Truncus arteriosus TAPVR

No. of Deaths

Mortality

11 1 12 1 2 3 3

3.0 0.5 2.2 3.0 6.3 10.7 13.0 6.7

1 5 2 2 0 0 0 0 0 1 44

( OO/ )

35.7 66.7 40.0 0 0 0

0 0 16.7 5.6

72 70 49 29 18

9

16 5 2 8 269

3 0 0 2 30

18.8 0 0 25.0 11.2

81 27 18 5

8 7 5 1

9.9 25.9 27.8 20.0

7 5 8 151

0 2 0 23 97

0 40.0 0 15.2

1,202

8 7 0 1

12.5 11.4 14.3 0

5.6

8.1

VSD = ventricular septal defect; ASD = atrial septal defect; TF = tetralogy of Fallot; PS = pulmonary stenosis; Rupt Valsalva ruptured aneurysm of the sinus of Valsalva; ECD = endocardia1 cushion defect; TGV = transposition of the great vessels; (T)APVR = (total) anomalous pulmonary venous return; A-V defect = atrioventricular defect (right atrium-left ventricle

=

fistula); A1 = aortic insufficiency.

298 The Annals of Thoracic Surgery Vol 21 No 4 April 1976

risk. Although this series included tetralogy of Fallot, endocardial cushion defect, and ruptured aneurysm of the sinus of Valsalva, the patients had rather mild anatomical and hemodynamic abnormalities that were considered to be operable within one hour. Anesthesia was induced by thiopental and succinylcholine and maintained by ether. For cooling, an operating table having an immersion bath was used. When the esophageal temperature reached 26" or 25"C, cooling was suspended. A mediastinal incision was made and total circulatory arrest was effected by encircling the superior and inferior venae cavae and the aorta. After the intracardiac procedure, the patient was warmed by the immersion bath attached to the operating table. Warming was suspended when the esophageal temperature reached 33" or 34°C. The typical course of a patient having deep hypothermia utilizing the immersion method is depicted in Figure 1.

enough to require an intracardiac procedure lasting more than one hour and when his hemodynamic state was poor, making him a higher operative risk. Such lesions included ventricular septal defect with high pulmonary resistance, complete endocardial cushion defect, pulmonary stenosis with low cardiac output, transposition of the great vessels, the severe form of tetralogy of Fallot, single ventricle, and truncus arteriosus . Anesthesia was induced with halothane inhalation and intravenous administration of succinylcholine and maintained with halothane and nitrous oxide. An anterior mediastinal incision was made, and following adequate heparinization a pump oxygenator was linked up between the aorta and the superior and inferior venae cavae. Using roller pumps, a Travenol bubble oxygenator, and BrownHarrison heat exchangers, hypothermia wag immediately induced with rapid cooling of the entire body and perfusion warming of the coroHypotherrnia Utilizing Rapid nary circulation through the cannula into the Extra corp oreal Cooling aortic root (Fig 2). Hemodilution of 25 to 30% of A patient was considered for extracorporeal the patient's estimated circulating blood volume cooling only when his lesions were was done using lactated Ringer's solution. Extracorporeal cooling was suspended when the Fig I . Operative course of a 10-year-old boy with esophagus reached a temperature 2" to 3°C ventricular septal defect who underwent repair higher than the target body temperature, usuutilizingimmersion hypothermia. (BT= body ally 22" to 23°C for deep hypothermia and temperature; BP= blood pressure; R = pulse rate; SCC = succinylcholine.) 30" to 33°C for mild or moderate hypothermia.

BTXBPXRP

93 38 160 28

Intubation

1

Cooling

Extubation

Rewarming

1

esophageal temperature ( B T ) pulse rate ( R ) systolic blood pressure (BPI

diastolic blood pressure (BP)

26- 40- 4-

24. 20- 0--

9.30

I

Ether 6 1 . 5 ~(2.2cc/kg) ~ assist. Resp.

10.00

10.30

11.00

11.30

contr. Resp.

L-

12.00

12.30

TIME

13.00

assist. Resp.

13.30

14.00

14.30

299 Taguchi et al: Congenital Heart Disease and Hypothermia

10 12

I

Fig2. Extracorporeal circuitry designed for rapid extracorporeal cooling and rewarming. T h e heart and total body can be perfused through separate h e a f exchangers. (1= arterial cannulation line; 2 = coronary irrigation line; 3 , 4 = heat exchangers; 5 = S w a n k filter; 6 = arterial p u m p ; 7 = oxygenator; 8 = superior vena cava cannulation line; 9 = inferior vena cava cannulation line; 10 = cardiotomy sucker; 11 = autofiltration circuitry; 12= arterial cannulation line for autofiltration.)

Extracorporeal flow was gradually decreased, corresponding to the decline in body temperature, and at 22" to 23°C the flow was controlled to about 10 to 20 ml per kilogram of body weight per minute. For very complicated intracardiac procedures the operation was conducted using complete circulatory arrest, but in most cases minimal extracorporeal flow was continued. Rapid rewarming was begun about 10 minutes before the expected completion of the intracardiac procedure. The blood flow of 10 to-20mllkg

was gradually increased, and when the esophageal temperature reached 32OC, flow was elevated to 80 to 100 mllkg. Warming was suspended when the esophageal temperature attained 34.5" to 35.5"C.

Clinical Results

Open-Heart Operations using immersion Hypothermia Of the 782 patients with congenital heart disease who underwent open-heart operations using immersion hypothermia, 44 died, a mortality of 5.6% (see Table I). The mortality rate was less than 10% in patients who had ventricular septal defect, atrial septal defect with or without pulmonary stenosis, or pure pulmonary stenosis. Patients with tetralogy of Fallot, endocardia1 cushion defect, ventricular septal defect complicated by pulmonary stenosis, transposition of

300 The Annals of Thoracic Surgery Vol 21 No 4 April 1976

the great vessels, and total anomalous pulmonary venous return had a mortality rate exceeding 10%. The duration of complete circulatory arrest under immersion hypothermia was from 4 to 56 minutes, and intracardiac operations were conducted within less than one hour (Table 2). The lowest temperature in these patients was 20.4" to 26.8"C. Tetralogy of Fallot and endocardial cushion defect required the longest period of circulatory arrest, with mean times of 38 and 41 minutes, respectively. There was no direct relationship between the duration of circulatory arrest and the lowest esophageal temperature. Age was definitely a factor in the outcome (Table 3). Six of the 30 patients less than 2 years of age died, a mortality rate of 20°/0, while of the 752 patients older than 2 years 38 died, a 5.0570 mortality. Two of the 3 patients less than 1year old died, a very high mortality rate of 66.770. Major and fatal complications are listed in Table 4. Psychoneurological disorders, pulmonary complications, difficult or impossible cardiac resuscitation from circulatory arrest, and severe metabolic acidosis were major and lifethreatening complications. Although pulmonary complications were frequently observed in this series, they were thought to be much less

Table2. Lowest Esophageal Temperature andDuration of Circulatory Arrest in Immersion Hypotkermia

Lesion

Lowest Esophageal Temperature ("C)

Time of Circulatoly Arrest (min)

VSD ASD VSD, ASD PS TF Rupt Valsalva PS, VSD ECD APVR A-V defect Coronary fistula

24.4 (20.4-26.3) 24.6 (22.4-26.8) 24.1 (22.2-25.3) 24.1 (22.3-25.3) 22.0 (21.0-24.8) 24.2 (22.2-26.0) 22.8 (20.8-23.9) 23.3 (20.7-24.3) 23.3 (20.7-24.3) 24.5 (24.G25.0) 24.4 (23.9-24.8)

18 (8-44) 12 (4-24) 21 (13-39) 17 (9-31) 38 (31-45) 22 (15-43) 25 (17-33) 41 (21-56) 32 (22-44) 17 (12-22) 13 (12-14)

Abbreviations same as for Table 1

Table 3 . Age of Patients Undergoing Hypofkermia and Relationship to Mortality Type of HYPOthermia Immersion

Total Extracorporeal cooling

Total

Mortality

Age (Yr)

No. of Patients

NO. of Deaths

(%)

30

3 27 129 218 189 140 63 13 782

2 4 10 11 8 4 2 3 44

66.7 14.8 7.8 5.0 4.2 2.9 3.2 23.1 5.6

12

23 34 89 174 76 24 420

8 11 15 11 7 1 53

34.8 32.4 16.9 6.3 9.2 4.2 12.6

common than with other methods of hypothermia.

Open-Heart Operations under Hypotkermia Utilizing Extracorporeal Cooling Utilizing rapid extracorporeal cooling, a total of 269 patients underwent surgical repair under mild to moderate hypothermia and 151 patients had deep hypothermia (see Table 1).Those undergoing mild to moderate hypothermia who had ventricular septal defect with high pulmonary resistance, tetralogy of Fallot, endocardial cushion defect, or ventricular septal defect with aortic insufficiency had a higher mortality rate (> 10%); those with pulmonary stenosis, congenital valve disease, or ruptured aneurysm of the sinus of Valsalva had a mortality rate less than 1070. Because of high pulmonary resistance, 2 patients with atrial septal defect had hypothermia with extracorporeal cooling, and both survived. Thus, the overall mortality rate with mild or moderate hypothermia was 11.2%. Of the patients whose lesions were repaired under deep hypothermia, those with transposition of the great vessels, single ventricle, single

301 Taguchi et al: Congenital Heart Disease and Hypothermia

Table 4 . Major Complications among Patients Undergoing Hypotherrnia Immersion Hypothermia (782 patients)

Rapid Extracorporeal Cooling (420 patients)

No. of Complications & %

No. of Complications

& %

No. of Deaths

Complicationa

No. of Deaths & %

Cerebral damage Spinal complication Psychiatric disorder Pulmonary complications Low cardiac output syndrome Myocardial failure Severe acid-base imbalance Renal failure Hepatic disorder including hepatitis Hemorrhagic diathesis Massive gastrointestinal bleeding Throm boemboli sm Impossible to resuscitate

7 (0.90) l(0.13) 8 (1.02) 13 (1.66) 13 (1.66) 13 (1.66) 12 (1.53) 5 (0.64) 3 (0.38) 3 (0.38) 4 (0.51) 1 (0.13) 10 (1.28)

6 (0.77) l(0.13) 0 4 (0.51) 7 (0.90) 4 (0.51) 6 (0.77) 2 (0.26) l(0.13) l(0.13) 2 (0.26) 0 10 (1.28)

5 (1.19) 0 3 (0.71) 24 (5.71) 19 (4.52) 7 (1.67) 7 (1.67) 5 (1.19) 4 (0.95) 7 (1.67) 3 (0.71) 0 18 (4.29)

5 (1.19) 0 0 8 (1.90) 11 (2.62) 2 (0.48) 2 (0.48) 4 (0.95) 0 1 (0.24) 2 (0.48) 0 18 (4.29)

& %

aWhen a patient developed several complications, the major one was selected for tabulation.

atrium with complete endocardia1 cushion defect, or truncus arteriosus had a mortality rate over 20%; those with the extreme form of tetralogy of Fallot, double-outlet right ventricle, or total anomalous pulmonary venous return had a mortality rate not exceeding 10%. Of these 420 patients, complete circulatory arrest was effected in 128. During complete circulatory arrest, perfusion with low flow rates of 10 to 20 mllkglmin was done in 98 patients. The total period of complete circulatory arrest with intermittent perfusion ranged from 24 to 112 minutes. The average duration of complete arrest varied according to disease group, but the minimum was 37 minutes for patients with tetralogy of Fallot and averaged 84 minutes for patients with truncus arteriosus. The lowest body temperature during circulatory arrest was between 17.5" and 27.8"C. During rapid extracorporeal cooling and warming, the extracorporeal flow rate was controlled depending on the body temperature; but even at the same temperature an effort was made to increase the flow volume during the warming stage rather than during cooling. In this group of patients there was also a large difference in mortality between those less than 2

and patients 2 or more years of age (see Table 3). Of the 57 patients less than 2 years old 19 died, a mortality rate of 33.3%, while 34 of the 363 patients 2 years or more in age died, a mortality of 9.37%. Considering the severity of disease in this group, however, the mortality rate in the younger age group was better compared with the patients who underwent immersion hypothermia. Table 4 reveals an increased incidence of major complications in this group, reflecting the severity of disease and the prolonged duration of the intracardiac procedures needed. All 5 patients who had cerebral damage were among those who had a total complete circulatory arrest time of over 100 minutes. Inability to resuscitate and low cardiac output syndrome occurred frequently despite use of the most current surgical techniques. Pulmonary complications, although of much higher incidence than with immersion hypothermia, have produced fewer clinical problems since we began using coronary warming during rapid cooling of the total body.

Comment Numerous basic studies have been made on the pathophysiology and metabolic aspects of

302 The Annals of Thoracic Surgery

Vol 21 No 4 April 1976

hypothermia, but it is extremely difficult to compare the results. This is because there are so many factors at variance, such as anesthetic agent used, method of cooling, method and type of ventilation, and use of extracorporeal circulation. In the application of hypothermia to open-heart surgery, the first consideration of importance is that of brain damage [l, 71. Although the longest period of circulatory arrest under immersion hypothermia was 56 minutes, in a patient with endocardia1 cushion defect, the majority of patients who survived without evidence of brain damage experienced 45 minutes or less of circulatory arrest (see Table 2). In contrast, the total time of complete circulatory arrest under extracorporeal rapid cooling ranged from 24 to 112 minutes with intermittent perfusion and a low flow rate, and there was a high incidence of brain damage among the patients with circulatory arrest over 90 minutes. It may therefore be concluded that the margin of safety is 45 minutes for immersion hypothermia and 90 minutes for extracorporeal cooling with intermittent perfusion. Open-heart operations under immersion hypothermia alone have the following disadvantages: 1. During both the cooling process and resuscitation from circulatory arrest, ventricular fibrillation is prone to develop, especially in infants. 2. Cardiac resuscitation may sometimes be extremely difficult, requiring cardiac massage for an extended period. 3. Rewarming of the central organs is slower by surface rewarming alone, and metabolic acidosis is liable to develop.

surface cooling and rewarming using cardiopulmonary bypass [13]. Another method is also used in which deep hypothermia is induced primarily by extracorporeal circulation followed by warming. We have employed rapid extracorporeal cooling with coronary warming irrigation. According to the literature [3, 141, the frequency of postoperative pulmonary insufficiency in the past has been high and many patients have developed pulmonary edema during extracorporeal cooling. With our method, to overcome this complication, during rapid cooling the heart is irrigated with warm blood, and only when the esophageal temperature drops below 25°C is the heart also rapidly cooled. When the central organs are chilled in the rapid cooling process, the pumping action of the hypothermic heart deteriorates and pulmonary congestion tends to develop. Our method controls this. In comparison to cardiopulmonary bypass or simple deep hypothermia alone, the Kyoto University method has, we believe, the following advantages: 1. Because cooling is rapid, there is no great difference in operating time required in comparison with that needed for extracorporeal circulation alone. 2. As cardiac function can be satisfactorily maintained during rapid cooling, pulmonary congestion does not develop and the incidence of pulmonary complications is low. 3. During rapid warming, the need for cardiac resuscitation is very rare. 4. Even when hypothermia of about 20°C is achieved and circulatory arrest time in excess of the safe margin is needed, it is possible to repeat circulatory arrest by perfusion with a low flow rate. 5. The incidence of acid-base imbalance is low.

These are the reasons for our unsatisfactory results in infants less than 2 years of age. However, as our results in 782 patients indicate, sur- References gical repair of most common congenital heart Almond CH, Jones JC, Snyder HM, et al: Cooling defects can be performed using immersion gradients and brain damage with deep hypothermia. J Thorac Cardiovasc Surg 48:890, hypothermia with a comparatively high level of 1964 safety. Baffes TG: Total body perfusion in infants and A method to overcome the limitations of imsmall children for open heart surgery. J Pediatr mersion hypothermia alone has been deSurg 3:551, 1968 veloped, the so-called Kyoto University method, Barratt-Boyes BG, Simpson M, Neutze JM: Inin which deep hypothermia is effected by tracardiac surgery in neonates and infants using

303 Taguchi et al: Congenital Heart Disease and Hypothermia

4. 5.

6. 7.

8.

9.

deep hypothermia with surface cooling and limited cardiopulmonary bypass. Circulation 43,44:Suppl 1:25, 1971 Belsey RHR, Dowlatshahi K, Keen G, et al: Profound hypothermia in cardiac surgery. J Thorac Cardiovasc Surg 56:497, 1968 Bigelow WG, Lindsay WL, Greenwood WF: Hypothermia: its possible role in cardiac surgery. Investigation of factors governing survival in dogs at low temperatures. Ann Surg 132:284,1950 Breckenridge IM, Oelert H, Graham GR, et al: Open heart surgery in the first year of life. J Thorac Cardiovasc Surg 65:58, 1973 Brierley JB: Neuropathological findings in patients dying after open heart surgery. Thorax 18:291, 1963 Ching E, DuShane JW, McGoon, DC, et al: Total correction of cardiac anomalies in infancy using extracorporeal circulation: surgical considerations and results of early operation. J Thorac Cardiovasc Surg 62: 117, 1971 Hikasa Y, Shirotani H, Muraoka R, et al: Open heart surgery under two years of age using deep hypothermia with surface cooling and partial cardiopulmonary bypass. J Cardiovasc Surg (Torino) 15:231, 1974

10. Horiuchi T, Koyamada K, Matano I, et al: Radical operation for ventricular septa1 defect in infancy. J Thorac Cardiovasc Surg 46: 180, 1963 11. Mohri H, Hessel FA 11, Nelson RJ, et al: Use of Rheomacrodex and hyperventilation in prolonged circulatory arrest under deep hypothermia induced by surface cooling: method for open heart surgery in infants. Am J Surg 112:241, 1966 12. Mori H, Muraoka R, Yokota Y, et al: Deep hypothermia combined with cardiopulmonary bypass for cardiac surgery in neonates and infants. J Thorac Cardiovasc Surg 64:422, 1972 13. Muraoka R, Miki S, Tsushimi K, et al: Respiratory care following open-heart surgery in infants. Gekashinryo 10:1449, 1968 14. Rittenhouse EA, Mohri H, Dillard DH, et al: Deep hypothermia in cardiovascular surgery. Ann Thorac Surg 17:63, 1974 15. Sealy WC, Brown IW Jr, Young WG Jr, et al: Hypothermia and extracorporeal circulation for open heart surgery: its simplification with a heat exchange for rapid cooling and rewarming. Ann Surg 150:627, 1959 16. Swan H, Zeavin I, Blount SG, et al: Surgery by direct vision in open heart during hypothermia. JAMA 153:1081, 1963

Notice from the American Board of Thoracic Surgery The 1977 annual certifying examination of the American Board of Thoracic Surgery (written and oral) will be held in Chicago on March 17-19, 1977. Final date for filing application is

August 1, 1976. Please address all communications to the American Board of Thoracic Surgery, 14624 E Seven Mile Rd, Detroit, MI 48205.

Surgical treatment of congenital heart disease with special reference to the application of hypothermia.

This report presents the results of operation for congenital heart disease using two different methods of hypothermia: (1) Immersion hypothermia alone...
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