Operative Closure of Isolated Defects of the Ventricular Septum: Planned Delay

Transcription

1 Operative Closure of Isolated Defects of the Ventricular Septum: Planned Delay R. Darryl Fisher, M.D., Scott L. Faulkner, M.D., C. Gordon Sell, M.D., Thomas P. Graham, Jr., M.D., and Harvey W. Bender, Jr., M.D. ABSTRACT Selection of patients and the timing of operation for closure of ventricular septal defect (VSD) can be difficult because the risk of operation must be balanced against the hemodynamic abnormality and the age and size of the infant. In the past 6 years we have individualized our approach to the timing and necessity of operation in the patient with an isolated VSD. During this period, 133 patients with VSD were evaluated, and 71 underwent operative closure of the VSD. Of the 133 patients, 90 were 2 years old or younger, and 40 of them required operation because of congestive failure and growth retardation. Of the 45 infants who did not undergo operation, 17 have small intracardiac shunts with normal pulmonary vascular resistance while the other 28 infants remain compensated and are growing despite moderate left-to-right shunts. A persistent, large intracardiac shunt was the indication for operation in 31 of the 48 older patients; the other 17 older patients remain well. Although 3 severely growth-retarded infants (2 to 4 kg) died soon after operation, all infants weighing 4 kg or more survive. No child has died during preoperative observation, and irreversible pulmonary vascular changes have not occurred. Most infants with VSD and large intracardiac shunts do require early VSD closure, but the risk of operation remains high in the tiny neonate with profound failure. With appropriate hemodynamic and clinical criteria, operation for selected infants can be delayed so that the risk of operation can be minimized. During the past 6 years we have approached the treatment of patients with an isolated defect of the ventricular septum on an individualized basis because the selection of patients and the From the Department of Cardiac and Thoracic Surgery, Vanderbilt University Hospital, Nashville, TN. Presented at the Twenty-fourth Annual Meeting of the Southern Thoracic Surgical Association, Nov 3-6, 1977, Marco Island, FL. Address reprint requests to Dr. Bender, Department of Cardiac and Thoracic Surgery, Vanderbilt University School of Medicine, Nashville, TN timing of operative closure must be balanced against the hemodynamic abnormality and age of the patient. In this series, prompt operation was performed when necessary and, in particular, operative closure was performed for all patients with intractable congestive heart failure, regardless of age or size. On the other hand, operative closure of the defect was delayed for several months in the small and growthretarded infant who responded to vigorous medical therapy. Corrective operation was electively performed in those older infants and children with a persistent intracardiac shunt of hemodynamic importance. In an effort to define the effectiveness of this approach, we reviewed the clinical course of all patients with an isolated defect of the ventricular septum undergoing treatment and evaluation at the Vanderbilt University Medical Center since Material Since July 1, 1971, 133 patients with an isolated defect of the ventricular septum had cardiac catheterization at our institution. There were 64 boys and 79 girls. The age distribution of the patients at the time of diagnosis was as follows: 0 to 4 months, 22 patients; 4 to 7 months, 20 patients; 7 to 13 months, 13 patients; 13 to 19 months, 17 patients; 19 to 25 months, 18 patients; and 25 months or older, 43 patients. Of the 133 patients, 85 were less than 2 years old when we first saw them. Operative Group To date, 71 patients have undergone operative closure of the ventricular septal defect (VSD). At the time of operation, 40 of the 71 patients (56%) were less than 2 years old (Table); all 40 infants exhibited growth retardation and intractable congestive failure. Of these 40 patients, 33 were less than 18 months old. Within 3 months after the diagnosis was made, 25 of the 40 infants underwent operative clo by R. Darryl Fisher

2 352 The Annals of Thoracic Surgery Vol 26 No 4 October 1978 Distribution of Patients by Age at the Time of Operation for the 71 Patients Undergoing Operation and by Age at the Time of Diagnosis for the Medical Group Patients Age (mo) Operative Group Medical Group More than Total sure of the VSD; 15 had delayed operations. The prompt approach to operative treatment in these 25 patients reflected the severity of the hemodynamic abnormality. They all exhibited intractable congestive failure that remained uncontrollable even during inpatient medical management. On the other hand, periods of medical treatment of 3 to 22 months were possible in the remaining 15 patients undergoing operation who were 2 years old or younger. The congestive failure in these 15 patients initially responded to medical treatment, but each patient remained severely growth retarded. When these infants approached 2 years of age, operation was performed. Older patients with persistent VSD and major left-to-right shunt included the remaining 31 patients in the operative group. They generally underwent operative closure of the defect at a convenient elective time, usually within 6 months following diagnostic catheterization. Pulmonary artery banding was not employed for palliation in patients with isolated defect of the ventricular septum during this period. Medical Group Of the 133 patients with isolated defect of the ventricular septum, operative closure was delayed, deferred, or proved unnecessary in 62 patients. The age distribution of these 62 patients at the time of diagnosis is shown in the Table. At the time of diagnosis, 90 patients of the entire group of 133 were less than 2 years old. 62 To date, 45 of them have been observed and have not undergone operative closure of the VSD. These 45 patients comprise 73% of the patients being observed medically. Three clinical categories became evident in our recommendations for either nonoperative treatment or delayed operative treatment. First, in the infant with severe congestive failure and growth retardation who responded to medical treatment, operation was delayed until the patient was about 2 years old; relief of the signs and symptoms of failure and progressive growth, although below normal, were used as criteria for delayed operation in these infants. Second, unrelenting congestive failure remained an indication for operation regardless of age or size. Third, the patient who was more than 2 years old with a VSD and major intracardiac shunt was considered to have a persistent defect, and operation was done electively. Operative Methods The technical aspects for operative closure of isolated defects of the ventricular septum have been refined by many individuals in recent years [2-4,161. Our technique for repair has not differed from the standard methods and usually consisted of complete cardiopulmonary bypass, with moderate general body hypothermia (30 C). Recently, in 13 small infants, profound hypothermia and circulatory arrest with surface cooling and extracorporeal core cooling and rewarming were utilized. The defect in the ventricular septum was always closed with a knitted Dacron patch tailored to slightly exceed the dimensions of the defect. Generally, 3 to 5 interrupted mattress sutures of 5-0 monofilament material were placed in the inferior margin of the defect. The remainder of the perimeter of the patch was attached to the margin of the defect by a continuous suture. Of the VSDs corrected in this manner, 74% proved to be infracristal (type 11). Early in this experience, all defects were closed through a vertical right ventriculotomy; more recently, the transatrial approach has proved useful, especially in the small infant undergoing repair by means of the technique of profound hypothermia and circulatory arrest. A patent ductus arteriosus was ligated in 4 patients before cardiopulmo-

3 353 Fisher et al: Closure of Isolated VSDs nary bypass. A patent foramen ovale or an ostium secundum atrial septal defect was closed,oo in 11 patients. Removal of a previously placed pulmonary arterial band and widening of the narrowed main pulmonary artery by a patch graft was necessary in 10 patients more than years old who had been seen elsewhere initially. rnm Hg Cardiac catheterization is recommended in all patients despite complete clinical recovery at 50-6 months to 1 year after operation to verify the completeness of the repair. Of the 71 patients, 28 have now undergone postoperative cardiac catheterization. 25- Results Operative Group Of the 71 patients undergoing closure of the VSD, 3 (4.2%) died after operation. They were 3 severely growth-retarded infants weighing 2.8 to 3.6 kg. Two of the 3 infants were less than 3 months old at the time of operation, and 1 of these had sustained a preoperative cardiac arrest. The other infant was 9 months old and weighed 3.6 kg. Postmortem examination was performed for 2 of the 3 infants; secure closure of the defect had been accomplished in each. Among the 38 patients undergoing operative closure of an isolated defect of the ventricular septum since July, 1974, there have been no deaths. There were apparently no unique intraoperative or postoperative complications associated with the operative closure of the isolated septal defect in these patients. All patients underwent controlled or intermittent ventilation for the first 24 hours following operation; however, 9 patients required an additional 24 hours of mechanical ventilation, and 5 patients required ventilatory support for longer than 48 hours. Transient, mild congestive heart failure appeared in the early postoperative period in approximately one-fourth of the 71 patients, but it was easily controlled with digitalis and diuretics. Early supraventricular and ventricular arrhythmias were infrequent and were readily suppressed by medication. Complete heart block did not occur during the postoperative period in any patient. Positive inotropic agents Preoperative and postoperative pulmonary artery systolic pressure in 28 patients who underwent postoperative cardiac catheterization. were used in the immediate postoperative period in 12 of the 71 patients undergoing operative closure. Only 1 patient who underwent operative closure of the defect by conventional methods of cardiopulmonary bypass had transient focal seizures in the immediate postoperative period. Complete postoperative cardiac catheterization data were available on 28 patients for comparison with the preoperative study. All postoperative studies were done 6 to 12 months after the procedure. No major residual ventricular septal defects were detected. The reduction in pulmonary artery pressure after operation is shown in the Figure. Medical Group To date, of the 133 patients in the series, 62 have not undergone operative closure of the VSD for various reasons. Twenty-nine patients were found to have a small intracardiac shunt, with normal pulmonary artery pressure. Four patients exhibited a reduction in intracardiac shunting by sequential cardiac catheterization,

4 354 The Annals of Thoracic Surgery Vol 26 No 4 October 1978 and spontaneous or partial closure of the defect was assumed in each instance. The other 29 patients remain compensated despite moderate to large intracardiac shunts (QP/Qs greater than 211). Of these 29 patients, all but 1 are younger than 2 years of age. None have been scheduled for operation, but most will probably require operative closure of the defect. There was 1 death among the 62 patients not undergoing operation. This was a 9-month-old child who died of bacterial meningitis. Comment The individualized approach to the patient with an isolated defect of the ventricular septum recognizes and places in perspective the several important, but different, features of the natural history of this malformation. It makes early operation available to the symptomatic infant, but it delays elective operative closure until later for the infant who responds to medical treatment. As a result of this planned delay, the possibility of spontaneous closure is realized without notably risking the threat of irreversible pulmonary vascular changes. Spontaneous closure is an enticing possibility for the patient with an isolated defect of the ventricular septum. The reported and inferred frequency of spontaneous, complete closure of such defects is projected to be in the range of 25 to 50% [7, 8, 10, 121. Spontaneous closure has been even more common in children with small defects of the ventricular septum [ll, but has been rare in the patient with a large defect 19, 131. Clinical observation of the symptomatic neonate with a large VSD who improves during the first year of life is not uncommon, and this clinical improvement has often been demonstrated to be a result of partial closure of the defect and associated reduction in left-to-right shunting. In view of these observations, planned delay in the small infant occasionally seems prudent, particularly if the hemodynamic burden is not great. The threat of irreversible pulmonary vascular changes has led many surgeons to advocate palliative pulmonary artery banding and others to recommend primary operative closure of the defect in the neonate. Although the exact mechanism of irreversible pulmonary vascular changes and the age of onset are not clear, several common features are evident in patients with VSD and pulmonary vascular changes. Pulmonary hypertension and pulmonary vascular disease are almost always associated with large defects, and those patients with medium or small defects seldom have changes in pulmonary vascular resistance. Age is another important consideration in the development of pulmonary vascular changes. Pulmonary vascular resistance generally increases with age in the patient with a large VSD and a large shunt unless pulmonary blood flow is reduced by operation or by spontaneous closure [ll]. However, most patients with large left-to-right shunts have large defects with low pulmonary vascular resistance during their early months and years of life [9]. Patients younger than 1 year of age who have large defects have low pulmonary vascular resistance; this combination is unusual in older patients [6]. In contrast, virtually all patients with small to moderate defects have normal pulmonary vascular resistance that remains normal even with advancing age. The risk of bacterial endocarditis in the patient with an isolated defect of the ventricular septum is exceedingly low. In recent years, there has been a declining incidence of bacterial endocarditis in patients with an isolated defect of the ventricular septum. Epidemiological studies by Shah and associates [15] place the frequency of bacterial endocarditis for patients with VSD at 1 in 1,000 patient-years of follow- UP. In consideration of these variables in the clinical course of patients with a defect of the ventricular septum, we have now fairly well standardized our treatment approach to the individual with a defect of the ventricular septum. It seems apparent that patients with isolated VSD comprise three groups distinguished by clinical and hemodynamic criteria: (1) the symptomatic infant, (2) the older infant with a persistent major defect, and (3) the older asymptomatic child with a mild to moderate shunt. First, the symptomatic infant comprises the groups of patients requiring the most skill and judgment for correct and timely therapy. Inten-

5 355 Fisher et a1 Closure of Isolated VSDs sive medical treatment is tried for the infant who experiences symptoms of congestive heart failure during the first 24 months of life; if the infant improves with medical treatment, operation is delayed. In many of these infants who respond to treatment, the defect may close or become smaller spontaneously in the coming months. If the congestive failure persists or worsens, primary operative closure of the defect is performed at this early age. Although delayed operation seems desirable in the early months of life and is often possible, we do not advocate delay in primary closure of the defect in the infant with persistent refractory congestive failure. Repeat catheterization is mandatory by 12 months of age in the infant with pulmonary hypertension who does not have operative closure, and closure is indicated if pulmonary hypertension persists. Second, for the older infant with a persistent modest but important shunt and normal pulmonary artery pressure, we tend toward watchful conservatism. These infants with a small to moderate left-to-right shunt and low pulmonary artery pressure run almost no risk of pulmonary vascular disease and have little added left ventricular work. The VSD in such a patient is quite likely to close or become smaller, but if closure has not occurred when the child reaches the immediate preschool years, we recommend elective closure at that time if the pulmonary to systemic flow ratio is approximately 2:l or greater. Third, for the asymptomatic older patient with a mild shunt and a small isolated defect of the ventricular septum, we do not recommend operation. For these patients, the risk of bacterial endocarditis is small; there are no physical limitations; and the small but real risk of operation can be avoided. This individualized approach accomplishes several objectives in the management of the patient with an isolated defect of the ventricular septum. It recognizes the possibility of spontaneous closure so that operative closure is delayed when feasible. This makes it unlikely that any defect that would have closed spontaneously is operatively closed. The risk of development of irreversible pulmonary vascular changes seems almost completely avoided by selective and early operation in the compensated infant with a large left-to-right shunt. This approach also endorses early operative closure when dictated by the clinical course of the patient. Our results and those of others [2, 3, demonstrate that the operative closure can now be accomplished with an acceptably low risk even in the neonate with refractory heart failure. These patients show an excellent functional result in terms of left heart size and performance [16]. However, it remains clear that the operative risk is greatest in the growthretarded infant who has profound congestive failure. The planned delay in operative closure for the small infant does allow rationally for growth and maturity of many infants with a moderate to large isolated defect of the ventricular septum to minimize the risk of operation. References 1. Ash R: Natural history of ventricular septal defects in childhood lesions with predominant arteriovenous shunts. J Pediatr 64:45, Barratt-Boyes BG, Neutze IM, Clarkson PM, et al: Repair of ventricular septal defect in the first two years of life using profound hypothermia circulatory arrest techniques. Ann Surg 184:376, Blackstone EH, Kirklin JW, Bradley EL, et al: Optimal age and results in repair of large ventricular septal defects. J Thorac Cardiovasc Surg 72:661, Ching E, DuShane JW, McGoon DC, et al: Total correction of ventricular septal defect in infancy using extracorporeal circulation: surgical considerations and results of operation. Ann Thorac Surg 12:1, Cordell D, Graham TP, Atwood GF, et al: Left heart volume characteristics following ventricular septal defect closure in infancy. Circulation 54:294, DuShane JW, Krongrad E, Ritter DG, et al: The fate of raised pulmonary vascular resistance after surgery in ventricular septal defect, in The Child with Congenital Heart Disease after Surgery. Edited by RD Rose, BSL Kidd. Mount Kisco, New York, Futura Publishing, Hoffman JIE: Natural history of congenital heart disease. Circulation 37:97, Hoffman JIE, Rudolph AM: Natural history of ventricular septal defect in infancy. Am J Cardiol 16:634, Hoffman JIE, Rudolph AM: The natural history of isolated ventricular septal defect with special ref-

6 356 The Annals of Thoracic Surgery Vol 26 No 4 October 1978 erence to selection of patients for surgery. Adv Pediatr 17:57, Li MD, Collins G, Disenhouse R, et al: Spontaneous closure of ventricular septal defects. Can Med Assoc J 100:737, Lucas RV Jr, Adams P Jr, Anderson RC, et al: The natural history of isolated ventricular septal defect. A serial physiologic study. Circulation 24:1372, MitchellSC, Korones SB, Berendes HW: Congenital heart disease in 56,109 births. Incidence and natural history. Circulation 43:323, Moore D, Vlad P, Lambert EC: Spontaneous clo- sure of ventricular septal defect following cardiac failure in infancy. J Pediatr 66:712, Rein JG, Freed MD, Norwood WI, et al: Early and late results of closure of ventricular septal defect in infancy. Ann Thorac Surg 24:19, Shah P, Singh WSA, Rose V, et al: Incidence of bacterial endocarditis in ventricular septal defects. Circulation 32:127, Subramanian S: Primary definitive intracardiac operation in infants: ventricular septal defect, in Advances in Cardiovascular Surgery. Edited by JW Kirklin. New York, Grune & Stratton, 1973 Notice from the American Board of Thoracic Surgery The American Board of Thoracic Surgery now requires that candidates pass both the written and oral portions of the certifying examination. In 1979 only, the two parts of the examination will be given together. The time and place is March 22-24, 1979, in Chicago, IL, and the closing date for registration was August 1,1978. In 1980 and thereafter, a written examination will be given prior to the oral examination. It will be necessary to pass the written examination before the oral examination can be taken. The closing date for registration is August 1, The exact times and places of these examinations will be announced later. Please address all communications to the American Board of Thoracic Surgery, E Seven Mile Road, Detroit, MI