Surgical Treatment of Congenital Heart Disease with Special Reference to the Application

Transcription

1 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., and Keiichi Takamura, M.D. ABSTRACT This report presents the results of operation for congenital heart disease using two different methods of hypothermia: () Immersion hypothermia alone. Of the 7 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,.6%). () Rapid extracorporeal cooling. Of the 69 patients with congenital heart diseases such as ventricular septa 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.%. In the 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.%. Since 9, when Bigelow and his associates [] experimentally demonstrated the usefulness of deep hypothermia, many reports [6] 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 [] 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, 97. Address reprint requests to Dr. Taguchi, Department of Surgery, Hiroshima University Hospital, -- Kasumi, Hiroshima, Japan 74. describing the pathological complications involved in applying the pump oxygenator to infants began to appear in the literature [,6,]. In this light, hypothermia has been reevaluated by several groups [lo,, 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,. At the Department of Surgery, Hiroshima University School of Medicine, and the Department of Cardiac Surgery, Hiroshima Citizens Hospital, from January, 96, to July, 974, hypothermia by the immersion method or by rapid extracorporeal cooling was applied to, patients 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, 7 were operated on using immersion hypothermia and 4 had rapid extracorporeal cooling (Table ). The age of these patients ranged from month to 4 years. As premedication, soya-lecithin and vitamin E were given orally at a dose of. gm per kilogram of body weight per day and to mg per day, respectively [9]. The patients were sedated the night before and % hours prior to operation; and / hours, hour, and minutes before the operation Vesprin (.4 mglkg), promethazine (. mglkg), Pethilorphane (. mglkg), and atropine (. 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 96

2 97 Taguchi et al: Congenital Heart Disease and Hypothermia Table. Congenital Heart Diseases Repaired or Palliated under Hypothermia Method of Hypothermia Lesion No. of No. of Mortality Patients Deaths ( O/O ) Immersion 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 Mild to moderate, utilizing rapid extracorporeal cooling VSD TF ECD PS Congenital valve diseases_ VSD, A Rupt Valsalva ASD Other Deep, utilizing rapid extracorporeal cooling Series total TF TGV Single ventricle Single atrium, ECD Double-outlet RV Truncus arteriosus TAPVR , 97. 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 = endocardia 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); A = aortic insufficiency.

3 9 The Annals of Thoracic Surgery Vol No 4 April 976 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 6" or "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 " or 4 C. 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 The typical course of a patient having deep Travenol bubble oxygenator, and Brownhypothermia utilizing the immersion method is Harrison heat exchangers, hypothermia wag depicted in Figure. immediately induced with rapid cooling of the entire body and perfusion warming of the coro- Hypotherrnia Utilizing Rapid nary circulation through the cannula into the Extra corp oreal Cooling aortic root (Fig ). Hemodilution of to % 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 -year-old boy with esophagus reached a temperature " to C ventricular septal defect who underwent repair higher than the target body temperature, usuutilizingimmersion hypothermia. (BT= body temperature; BP= blood pressure; R = pulse rate; ally " to C for deep hypothermia and SCC = succinylcholine.) " to C for mild or moderate hypothermia. BTXBPXRP 9 Intubation 6 Cooling Rewarming Extubation esophageal temperature (BT) pulse rate (R) systolic blood pressure (BPI diastolic blood pressure (BP) I Ether 6.~~ (.cc/kg) assist. Resp. L- contr. Resp. assist. Resp TIME

4 99 Taguchi et al: Congenital Heart Disease and Hypothermia I Fig. Extracorporeal circuitry designed for rapid was gradually increased, and when the extracorporeal cooling and rewarming. The heart esophageal temperature reached OC, flow was and total body can be perfused through separate heaf exchangers. ( = arterial cannulation line; = elevated to to mllkg. Warming was suscoronary irrigation line;,4 = heat exchangers; = pended when the esophageal temperature at- Swank filter; 6= arterial pump; 7 = oxygenator; = tained 4." to."c. superior vena cava cannulation line; 9 = inferior vena cava cannulation line; = cardiotomy sucker; = autofiltration circuitry; = arterial cannulation line for autofiltration.) Clinical Results Extracorporeal flow was gradually decreased, corresponding to the decline in body temperature, and at " to C the flow was controlled to about to 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 minutes before the expected completion of the intracardiac procedure. The blood flow of to- mllkg Open-Heart Operations using immersion Hypothermia Of the 7 patients with congenital heart disease who underwent open-heart operations using immersion hypothermia, 44 died, a mortality of.6% (see Table I). The mortality rate was less than % in patients who had ventricular septal defect, atrial septal defect with or without pulmonary stenosis, or pure pulmonary stenosis. Patients with tetralogy of Fallot, endocardia cushion defect, ventricular septal defect complicated by pulmonary stenosis, transposition of

5 The Annals of Thoracic Surgery Vol No 4 April 976 the great vessels, and total anomalous pulmonary venous return had a mortality rate exceeding %. The duration of complete circulatory arrest under immersion hypothermia was from 4 to 6 minutes, and intracardiac operations were conducted within less than one hour (Table ). The lowest temperature in these patients was.4" to 6."C. Tetralogy of Fallot and endocardial cushion defect required the longest period of circulatory arrest, with mean times of and 4 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 ). Six of the patients less than years of age died, a mortality rate of /, while of the 7 patients older than years died, a.7 mortality. Two of the patients less than year old died, a very high mortality rate of 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 Table. Lowest Esophageal Temperature andduration of Circulatory Arrest in Immersion Hypotkermia Time of Lowest Circula- Esophageal Temperature toly Arrest Lesion ("C) (min) VSD 4.4 (.4-6.) (-44) ASD 4.6 (.4-6.) (4-4) VSD, ASD 4. (.-.) (-9) PS 4. (.-.) 7 (9-) TF. (.-4.) (-4) Rupt Valsalva 4. (.-6.) (-4) PS, VSD. (.-.9) (7-) ECD. (.7-4.) 4 (-6) APVR. (.7-4.) (-44) A-V defect 4. (4.G.) 7 (-) Coronary fistula 4.4 (.9-4.) (-4) Abbreviations same as for Table Table. Age of Patients Undergoing Hypofkermia and Relationship to Mortality Type of Mor- HYPO- Age No. of NO. of tality thermia (Yr) Patients Deaths (%) Immersion Extracorporeal cooling < > < > common than with other methods of hypothermia. Open-Heart Operations under Hypotkermia Utilizing Extracorporeal Cooling Utilizing rapid extracorporeal cooling, a total of 69 patients underwent surgical repair under mild to moderate hypothermia and patients had deep hypothermia (see Table ). 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 (> %); those with pulmonary stenosis, congenital valve disease, or ruptured aneurysm of the sinus of Valsalva had a mortality rate less than 7. Because of high pulmonary resistance, patients with atrial septal defect had hypothermia with extracorporeal cooling, and both survived. Thus, the overall mortality rate with mild or moderate hypothermia was.%. Of the patients whose lesions were repaired under deep hypothermia, those with transposition of the great vessels, single ventricle, single

6 Taguchi et al: Congenital Heart Disease and Hypothermia Table 4. Major Complications among Patients Undergoing Hypotherrnia Immersion Rapid Extracorporeal Hypothermia Cooling (7 patients) (4 patients) No. of No. of No. of No. of Complications Deaths Complications Deaths Complicationa & % & % & % & % Cerebral damage 7 (.9) 6 (.77) (.9) (.9) Spinal complication l(.) l(.) Psychiatric disorder (.) (.7) Pulmonary complications (.66) 4 (.) 4 (.7) (.9) Low cardiac output syndrome (.66) 7 (.9) 9 (4.) (.6) Myocardial failure (.66) 4 (.) 7 (.67) (.4) Severe acid-base imbalance (.) 6 (.77) 7 (.67) (.4) Renal failure (.64) (.6) (.9) 4 (.9) Hepatic disorder including hepatitis (.) l(.) 4 (.9) Hemorrhagic diathesis (.) l(.) 7 (.67) (.4) Massive gastrointestinal bleeding 4 (.) (.6) (.7) (.4) Throm boemboli sm (.) Impossible to resuscitate (.) (.) (4.9) (4.9) awhen a patient developed several complications, the major one was selected for tabulation. atrium with complete endocardia cushion defect, or truncus arteriosus had a mortality rate over %; 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 %. Of these 4 patients, complete circulatory arrest was effected in. During complete circulatory arrest, perfusion with low flow rates of to mllkglmin was done in 9 patients. The total period of complete circulatory arrest with intermittent perfusion ranged from 4 to minutes. The average duration of complete arrest varied according to disease group, but the minimum was 7 minutes for patients with tetralogy of Fallot and averaged 4 minutes for patients with truncus arteriosus. The lowest body temperature during circulatory arrest was between 7." and 7."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 and patients or more years of age (see Table ). Of the 7 patients less than years old 9 died, a mortality rate of.%, while 4 of the 6 patients years or more in age died, a mortality of 9.7%. 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 patients who had cerebral damage were among those who had a total complete circulatory arrest time of over 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

7 The Annals of Thoracic Surgery Vol No 4 April 976 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, 7. Although the longest period of circulatory arrest under immersion hypothermia was 6 minutes, in a patient with endocardia cushion defect, the majority of patients who survived without evidence of brain damage experienced 4 minutes or less of circulatory arrest (see Table ). In contrast, the total time of complete circulatory arrest under extracorporeal rapid cooling ranged from 4 to 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 9 minutes. It may therefore be concluded that the margin of safety is 4 minutes for immersion hypothermia and 9 minutes for extracorporeal cooling with intermittent perfusion. Open-heart operations under immersion hypothermia alone have the following disadvantages:... During both the cooling process and resuscitation from circulatory arrest, ventricular fibrillation is prone to develop, especially in infants. Cardiac resuscitation may sometimes be extremely difficult, requiring cardiac massage for an extended period. Rewarming of the central organs is slower by surface rewarming alone, and metabolic acidosis is liable to develop. These are the reasons for our unsatisfactory results in infants less than years of age. However, as our results in 7 patients indicate, surgical repair of most common congenital heart defects can be performed using immersion hypothermia with a comparatively high level of safety. A method to overcome the limitations of immersion hypothermia alone has been developed, the so-called Kyoto University method, in which deep hypothermia is effected by surface cooling and rewarming using cardiopulmonary bypass []. 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 [, 4, 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 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: Because cooling is rapid, there is no great difference in operating time required in comparison with that needed for extracorporeal circulation alone. As cardiac function can be satisfactorily maintained during rapid cooling, pulmonary congestion does not develop and the incidence of pulmonary complications is low. During rapid warming, the need for cardiac resuscitation is very rare. Even when hypothermia of about 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. The incidence of acid-base imbalance is low. References Almond CH, Jones JC, Snyder HM, et al: Cooling gradients and brain damage with deep hypothermia. J Thorac Cardiovasc Surg 4:9, 964 Baffes TG: body perfusion in infants and small children for open heart surgery. J Pediatr Surg :, 96 Barratt-Boyes BG, Simpson M, Neutze JM: Intracardiac surgery in neonates and infants using

8 Taguchi et al: Congenital Heart Disease and Hypothermia deep hypothermia with surface cooling and limited cardiopulmonary bypass. Circulation 4,44:Suppl :, Belsey RHR, Dowlatshahi K, Keen G, et al: Profound hypothermia in cardiac surgery. J Thorac Cardiovasc Surg 6:497, 96. 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 :4,9 6. Breckenridge IM, Oelert H, Graham GR, et al: Open heart surgery in the first year of life. J Thorac Cardiovasc Surg 6:, Brierley JB: Neuropathological findings in patients dying after open heart surgery. Thorax :9, 96. Ching E, DuShane JW, McGoon, DC, et al: correction of cardiac anomalies in infancy using extracorporeal circulation: surgical considerations and results of early operation. J Thorac Cardiovasc Surg 6: 7, 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) :, 974. Horiuchi T, Koyamada K, Matano I, et al: Radical operation for ventricular septa defect in infancy. J Thorac Cardiovasc Surg 46:, 96. Mohri H, Hessel FA, 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 :4, 966. 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 64:4, 97. Muraoka R, Miki S, Tsushimi K, et al: Respiratory care following open-heart surgery in infants. Gekashinryo :449, Rittenhouse EA, Mohri H, Dillard DH, et al: Deep hypothermia in cardiovascular surgery. Ann Thorac Surg 7:6, 974. 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 :67, Swan H, Zeavin I, Blount SG, et al: Surgery by direct vision in open heart during hypothermia. JAMA :, 96 Notice from the American Board of Thoracic Surgery The 977 annual certifying examination of the American Board of Thoracic Surgery (written and oral) will be held in Chicago on March 7-9, 977. Final date for filing application is August, 976. Please address all communications to the American Board of Thoracic Surgery, 464 E Seven Mile Rd, Detroit, MI 4.