Long-term Results of Aortopulmonary Anastomosis for Tetralogy of Fallot

Transcription

1 Long-term Results of Aortopulmonary Anastomosis for Tetralogy of Fallot Morbidity and Mortality, By ROGER B. COLE, M.D., ALEXANDER J. MUSTER, M.D., DAVID E. FIXLER, AND MILTON H. PAUL, M.D. SUMMARY A review of 34 patients with tetralogy of Fallot undergoing aortopulmonary anastomosis of the Potts-Smith type (descending aorta to pulmonary artery) has been made for assessment of the complications and long-term results ( ) of this procedure. There were 3 operative deaths (9%) and 52 late medical deaths (2%) The symptomatic improvement has remained impressive in the survivors even up to 2 years after shunt surgery, with 85% of the patients having a functional classification of I or II. The major late complications have been related to anastomotic channels which were made or eventually became too large, resulting in congestive heart failure (2 late medical deaths) or in pulmonary hypertension with pulmonary vascular obstructive disease. These complications are not unique to the Potts operation, and may be anticipated in patients with excessively large ascending aorta to right pulmonary artery anastomoses. Careful patient follow-up is indicated and, in the event of congestive heart failure or evidence for pulmonary hypertension, an aggressive approach with either shunt take down and intracardiac repair or shunt revision should be considered. Additional Indexing Words: Aortopulmonary anastomosis IN A FIELD as rapidly changing as cardiac surgery it is mandatory to periodically reevaluate the efficacy of any operative procedure in the light of the present day alternatives. Certainly such is the case with the descending aortopulmonary anastomosis (Potts-Smith) in the surgical management of tetralogy of Fallot. From June 1946 to June 1969, 34 patients with the preoperative diagnosis of tetralogy of Fallot underwent descending aortopulmonary anastomosis at the Children's Memorial Hos- From The Children's Memorial Hospital (Willis J. Potts Children's Heart Center) and the Department of Pediatrics, Northwestern University Medical School, Chicago, Illinois. D. E. Fixler was supported by a National Institutes of Health Grant 5-T12-HE 577. Received April 16, 197; revision accepted for publication October 26, 197. PPotts operation 263 pital. In 1959, Paul, Miller, and Potts1 analyzed the results in the first 1 of these 34 patients (table 1). The major contribution of the 1959 review was to bring into sharp focus the long-term problems encountered in surviving patients. It was apparent that the major late medical mortality of morbidity of the procedure resulted from anastomotic channels which were either too large initially or had grown too large over the ensuing years, resulting in congestive heart failure, pulmonary hypertension, or pulmonary vascular obstructive disease. It is the purpose of this present paper to review our experience with the total of 34 patients undergoing descending aortopulmonary anastomosis for tetralogy of Fallot. Potential complications of the operation are stressed, as well as guidelines for recognition of these complications and their management

2 264 COLE ET AL. Table Analysis of the First 1 Patients Undergoing Descending Aortopulmnnary Anastomosis for Tetralogy of Fallot ( ) 1 Patients 91 Surgical survivors 9 Surgical deaths 8 Patients lost to follow-up 83 Patients followed ( ) 1 Late medical deaths 73 Patients alive as of 1959 by an aggressive diagnostic and therapeutic approach. Material From June 1946 to June 1969, 935 patients underwent systemic-pulmonary anastomosis at the Children's Memorial Hospital for various forms of cyanotic heart disease with diminished pulmonary blood flow. Five hundred twelve of the 935 patients had aortopulmonary anastomosis of the Potts-Smith type, and in 34 cases the preoperative diagnosis was tetralogy of Fallot. The diagnosis of tetralogy of Fallot cannot be rigidly interpreted here, since a large number of these patients, particularly in the early days of our heart surgery program ( ), underwent operation without catheterization or angiocardiographic studies. However, the following observations derived from subsequent autopsy, catheterization, or angiocardiographic studies in 22 of the 34 patients who had operations indicate that the clinical diagnosis derived from history, physical examination, electrocardiogram, and chest X-ray was generally accurate. Autopsy examination was performed in 89 cases, including operative deaths after aortopulmonary shunt or intracardiac repair as well as late medical deaths without surgical intervention. In 87 cases, the classical findings of tetralogy of Fallot were reported; in the remaining two cases, D-transposition of the great arteries with ventricular septal defect and pulmonary stenosis was present. One hundred sixty-six of the 34 patients diagnosed preoperatively as tetralogy of Fallot on clinical grounds underwent subsequent cardiac catheterization and angiocardiographic diagnostic studies. Tetralogy of Fallot pathology was confirmed in 159 of the 166 cases. In seven of the 166 patients, these studies indicated a diagnosis other than tetralogy; either single ventricle with pulmonary stenosis or transposition of the great vessels with pulmonary stenosis. From the above observations we would estimate the initial error in clinical diagnosis to be in the range of 5%. Method of Operation The size of the anastomosis was usually determined at operation by the use of calipers for measurement of the length of the incisions in the descending aorta and pulmonary artery. Initially, these incisions were made 8 mm long to allow for an anastomosis of approximately 5 mm in internal diameter.2 Marked postoperative enlargement of the heart early in the series prompted shortening of the incision to 6 mm, or an anastomotic diameter of 4 mm. Thereafter, incisions of 6 mm were made in patients over the age of 2 years and 5 mm in those under the age of 2 years. In 1965 a review of our surgical experience suggested the advisability of even smaller incisions. It was apparent that an inadequate aortopulmonary anastomosis was rarely encountered, since only five of the 31 surviving patients exhibited excessive cyanosis postoperatively. In three of these five instances, the anastomosis was performed on the right side in the presence of a right aortic arch, a procedure long since abandoned because of technical difficulties. It was equally apparent that the major late mortality and morbidity of the procedure resulted from anastomotic channels which were either too large initially or had grown too large over the ensuing years.3 At the time of reoperation for intracardiac repair or revision of the anastomosis it was not unusual for us to observe that the anastomotic channel had doubled or tripled in internal diameter. Accordingly, since 1965, incisions of 4 mm in the aorta and pulmonary artery have been performed in infants and children under the age of 2 years. Results In this presentation, attention will be focused upon the following aspects of the

3 AORTOPULMONARY ANASTOMOSIS 5- C5-ltin.D I: 3ic O cc W Ia Voi c;._ $\ --- Ci) CO "I o IcaX / a.i d a.; bo) a tdxa d P._ C5' a bri P.4.s Q X,II Ferur _5 o 197 CS +'o. a ~an- _ m a. ;d~.m.s: cd Cl a) a) ;. p W \ P \ patient group undergoing the descending aortopulmonary anastomosis: the "immediate" surgical mortality; the medical causes of late death in patients surviving at least 6 days after anastomosis (table 2, group A); and finally, the long-term results and medical complications in those patients still alive without subsequent surgery (table 2, group B). Those patients who have had intracardiac repair subsequent to the aortopulmonary anastomosis (table 2, group C) will not be discussed in this review. Surgical Mortality Thirty of the 34 patients diagnosed preoperatively as tetralogy of Fallot died at surgery or within 6 days after aortopulmonary anastomosis (table 3). In 22 of 24 autopsies performed in this group, the anatomic diagnosis was tetralogy of Fallot. The overall surgical mortality for the Potts-Smith operation has remained at about 9% over the years, averaging 12-15% under the age of 2 years, and 3-4% over the age of 2 years. Nonsurgical Mortality Fifty-two patients survived at least 6 days after anastomosis surgery, but succumbed subsequently without additional surgery (table 2, group A; table 4). 1. Congestive Heart Failure Without Pulmonary Vascular Obstructive Disease or Bacterial Endocarditis Twenty patients died with marked cardiomegaly, evidence of left heart failure, and clinical and radiographic evidence of increased pulmonary blood flow. The absence of Table 3 Surgical Mortality* (3 Patients) in Descending Aortopulmonary Anastomosis Surgery for Tetralogy of Fallot (34 Patients) Cause of death No. of patients Operative mortality (death within 24 hr) 1 Thrombosis of aortopulmonary anastomosis 4 Congestive heart failure 4 Bacterial endocarditis 2 Pneumonia 6 Insufficient data to determine cause of death *Death occurring within 6 days of anastomosis surgery. Volufme XLIII, February 1971

4 '266 COLE ET AL. Table 4 Nonsurgical Mortality of Descending Aortopulmonary Occurring 6 Days or More after Operation) Anastomosis Surgery (Death Age at anastomosis Age at death Patient Date of anastomosis (yr) (yr) A. Congestive heart failure without evidence of pul2monary vascular obstructive disease (2 patients) B.K S.H D.P R.R L.S /12 2 N.W H.Z /12 G.B K.F K.M R.W M.W S.P D.W. 19, G.P /12 D.M K.M. 195a 3 6 K.B D.V S.P B. Pulmonary vascular disease (8 patients) C.C D.P J.B R.C B.F /12 9 D.F J.P R.P C. Subacute bacterial endocarditis (6 patients) V.P G.J F.M R.T S.T E.M /12 D. Brain abscess (4 patients) C.K /12 M.K /12 T.E L.J pulmonary vascular disease was determined the time of death from congestive heart failure clinically by the marked cardiac enlargement was 5 months to 18 years, with an average of 9 and increased pulmonary blood flow in the years. The age of the patient at the time of presence of a loud, continuous anastomotic death ranged from 18 months to 24 years. All murmur and little or no cyanosis. deaths from congestive heart failure occurred The interval from the date of operation to in patients operated on prior to 1958, with 12

5 AORTOPULMONARY ANASTOMOSIS 267 Table 5 Radiographic Evaluation of Patients with Tetralogy of Fallot after Descending Aortopulmonary Anastomosis (111 Patients) One to Twenty Years Cardiothoracic ratio No. of patients Normal (<55%) (55-6%) (6-65%) (>65%) 1 of these deaths in patients operated on before Pulmonary Vascular Obstructive Disease Eight patients died as the result of rupture of a pulmonary artery aneurysm secondary to pulmonary vascular disease. Death occurred 3 to 18 years after surgery. Age at the time of death ranged from 6 to 28 years. Six of the eight cases were documented by postmortem examination. A seventh patient, known from cardiac catheterization to have severe pulmonary vascular disease (pulmonary vascular resistance units), died suddenly following the onset of severe chest pain. An eighth patient, suspected clinically to have pulmonary vascular obstruction, died following an episode of chest pain and hemoptysis. All eight patients were operated on prior to 1952 in the period when the anastomotic channels were, in retrospect, generally made too large. Since the majority of patients dying without additional surgery (table 2, group A) had not undergone cardiac catheterization, it was not possible to determine accurately the incidence of pulmonary hypertension and pulmonary vascular disease in this group. 3. Subacute Bacterial Endocarditis Six of the 52 late medical deaths resulted from bacterial endocarditis complicated by congestive heart failure in four and thrombosis of the aortopulmonary anastomosis in two patients. Taussig4 also commented on the high incidence of bacterial endocarditis in patients following subclavian-pulmonary anastomosis, citing 1 of 27 medical deaths in her series from bacterial endocarditis. In contrast, Keith, Rowe, and Vlad,5 reviewing the causes of death in unoperated patients with tetralogy of Pulmonary artery segment No. of patients Normal Fallot, found only two of 48 patients in whom bacterial endocarditis was the cause of death. In addition to the six cases where death was attributable to subacute bacterial endocarditis, there were 14 other patients in our series of 34 patients undergoing aortopulmonary anastomosis for tetralogy of Fallot who had a documented history of bacterial endocarditis with recovery. Two of the 14 patients had two documented episodes of bacterial endocarditis. 4. Brain Abscess The incidence of brain abscess as a primary cause of death following aortopulmonary anastomosis (fouir patients) did not seem to differ from its incidence as a cause of death in unoperated patients with tetralogy of Fallot. Keith, Rowe, and Vlad5 indicated brain abscess as a primary cause of death in four of 48 unoperated patients. In our series of 52 patients with medical deaths following aortopulmonary anastomosis, there were four documented cases of brain abscess as the terminal event. The time of death ranged from 3 months to 1 years postoperatively, and the age of the patients from 2 years to 14 years. There were three additional documented cases of brain abscess with recovery. 5. Inadequate Aortopulmonary Anastomosis (2 Patients) 6. Miscellaneous Noncardiac Deaths (7 Patients) 7. Insufficient Data for Determination of Catuse of Death (5 Patients) Long-term Survival Without Subsequent Operation Since congestive heart failure represented the leading cause of death in the nonsurgical mortality group (table 2, group A), the 113 patients known to be alive as of 1969 without

6 268 COLE ET AL. Table 6 Functional Classification6 of Patients with Tetralogy of Fallot Surviving 1 to 2 Years after Descending Aortopulmonary Anastomosis (Data on 13 out of 1 13 Patients) 1 to 2 years postoperative Functional classification No. of patients Per cent I II III IV Total 13 1 additional surgery after the initial anastomosis (table 2, group B) were reviewed for evidence of excessively large anastomotic channels. Recent chest roentgenograms were available in 111 of these 113 patients for analysis of overall heart size, prominence of the pulmonary artery segments, and pulmonary vascular markings (table 5). It appeared that the heart size correlated best with the size of the anastomosis, since prominence of the pulmonary artery segment may also be due to pulmonary hypertension and vascular obstructive disease without a continuing large shunt flow through the anastomosis. The pulmonary vascular markings, although often difficult to quantitate, are also of considerable value in assessment of the shunt flow. Table 6 presents the functional classification for 13 of the 113 patients in group B according to the functional criteria of the New York Heart Association.6 Since a large percentage of the patients in groups A and B have not undergone cardiac catheterization, it was not possible to determine accurately the incidence of pulmonary hypertension and pulmonary vascular obstructive disease after descending aortopulmonary anastomosis. Some assessment of the altered pulmonary hemodynamics following shunt surgery can, however, be gained by a review of the pulmonary artery pressure, blood flow, and vascular resistance data from 112 patients undergoing cardiac catheterization after anastomosis at the Children's Memorial Hospital at various postoperative intervals. The 112 patients were grouped according to the time interval between shunt operation and cardiac catheterization (table 7). Ninety-four per cent of the patients studied had resting arterial oxygen saturations over 8%, and 58% of the patients had arterial oxygen saturations of 9% or greater, indicating the prevalence of relatively high pulmonary blood flows. Thirtyone of the 112 patients undergoing cardiac catheterization had mean pulmonary artery pressure over 3 mm Hg, and 15 of these 31 had mean pulmonary artery pressures in excess of 5 mm Hg. Elevated pulmonary vascular resistance (greater than 4 units) was not observed when the mean pulmonary artery pressure was below 5 mm Hg (fig. 1). In the -5-year post-anastomosis study group, no patient had a mean pulmonary artery pressure greater than 5 mm Hg. In contrast, in the 5-1, 1-15, and Table 7 Mean Pulmonary Artery Pressure Following Aortopulmonary Anastomosis (112 Patients) No. of years after anastomosis Pulmonary artery mean pressure (mm Hg) (12 patients) (42 patients) (42 patients) (16 patients) < % Patients > 5 mm Hg % 14% 17% 19%o

7 AORTOPULMONARY ANASTOMOSIS 269.z z 1 S~ o 4.< 2 W. V'b PULMONARY VASCULAR RESISTANCE (L/mn/M2/mm. Hg) Figure 1 Tetralogy of Fallot with aortopulmonary anastomosis. Mean pulmonary artery pressure and calculated pulmonary vascular resistance. year post-anastomosis study groups, 14%, 17%, and 197? of each group, respectively, had mean pulmonary artery pressures greater than 5 mm Hg. Discussion The surgical management of the patient with tetralogy of Fallot remains to some extent individualized today, conditioned by the experience and capabilities within a given institution. In general, most children over the age of 4 years can best be managed by intracardiac correction but the surgical approach in infants and younger children continues to be an extracardiac, palliative operation.7-9 The subelavian-pulmonary operation of Blalock and Taussig1 has been and continues to be an effective operation for infants over the age of 12 to 18 months, but it has had a more limited application and poorer results in infants under this age. The size of the subelavian artery in a young infant is most often the limiting factor and, consequently, until the early 196's the descending aortopulmonary anastomosis described by Potts was performed by many surgeons when hypoxic spells necessitated palliation in infants less than 1 year of age. This review has concerned 34 patients undergoing descending aortopulmonary anas- Circulation, Volume XLJII, February 1971 tomosis for tetralogy of Fallot. Early in our own surgical experience, the operation was applied to children of all ages, and not limited to infants under 12 to 18 months of age. Of the total 34 patients operated upon, 7 were under the age of 12 months, and another 64 patients were between the ages of 12 and 24 months. The long-term results in these two younger groups were not significantly different from the experience in patients over 24 months of age. The symptomatic improvement after aortopulmonary anastomosis has remained impressive, with about 85% of all patients still alive without further surgery having a functional classification of I or II even up to 2 years after shunt surgery. There is, however, an appreciable risk of the development of congestive heart failure or pulmonary hypertension with eventual pulmonary vascular obstructive disease. These complications are primarily related to anastomotic channels which were made or became too large after operation. The length of the incisions in the descending aorta and pulmonary artery have, therefore, been periodically reduced from the originally described 8-mm incision to the present 4-mm incision in infants and children under the age of 2 years. This latter fact accounts for the higher incidence of these life threatening complications early in our surgical series before the potential dangers of an 8- or even a 6-mm incision were fully appreciated. Since 1962, anastomosis of the ascending aorta to the right pulmonary artery11-'3 hag become a commonly applied form of palliation and in large part has replaced the descending aortopulmonary artery anastomosis as the operation of choice in small infants with tetralogy of Fallot. In our limited experience with the ascending aortopulmonary anastomosis, there is much to suggest that the size of the anastomotic channel may be even more critical than with the Potts operation since anastomotic channels of 4 mm diameter in infants have led to the early onset of cardiac enlargement and left ventricular I.*9 * *: * ' * * 4

8 27 decompensation. In many institutions, digitalization is routinely prescribed immediately following operation. It seems reasonable to assume, therefore, that many of the observations regarding the long-term complications of the Potts operation are applicable as well to an ascending aortopulmonary artery anastomosis of comparable size. As suggested above, most children with tetralogy of Fallot who are over 4 years of age can best be managed surgically by intracardiac correction. In children requiring surgical intervention between the ages of 12 months and 4 years, the operation of choice is usually a palliative subelavian-pulmonary anastomosis, unless it is deemed not feasible on the basis of vessel anatomy. In infants under 12 months, an anastomosis between the aorta, itself, and a pulmonary artery is the preferred surgical approach. The ascending aortopulmonary anastomosis has taken precedence over the descending aortopulmonary shunt because the shunt site is more easily accessible at the time of "take down" and intracardiac repair. Our long-term observations on patients with the Potts shunt have made us sensitive to the recognition of the potential danger signs and to a more aggressive surgical management. The clinical findings which indicate a large left-to-right shunt through the anastomosis and warrant concern and early laboratory investigation include: (1) the almost complete absence of cyanosis following anastomosis; (2) a short, low-pitched, rough continuous murmur postoperatively; (3) progressive cardiac enlargement; (4) progressive prominence of the pulmonary artery segment and a marked increase in the pulmonary vascular marking; and (5) appearance and progression in left ventricular hypertrophy resulting in combined ventricular hypertrophy on electrocardiogram and vectorcardiogram. Late diminution or disappearance of a previously heard anastomotic murmur frequently denotes the presence of advanced pulmonary vascular obstructive disease. In the intervening years between anastomosis and intracardiac repair, frequent follow-up COLE ET AL. examinations are indicated for detection of the occurrence of these serious and often progressive and eventually irreversible complications. When evidence for congestive heart failure and excessive pulmonary blood flow with pulmonary hypertension exists, cardiac catheterization and angiocardiographic studies should be performed and, if intracardiac correction is not deemed feasible, subsequent revision with narrowing of the aortopulmonary anastomosis can be undertaken. Acknowledgment We wish to acknowledge the surgical contributions of Drs. W. J. Potts, A. DeBoer, W. L. Riker, T. G. Baffes, and F. S. Idriss. References 1. PAUL MH, MILLER RA, PoTTs WJ: Long-term results of aortic-pulmonary anastomosis for tetralogy of Fallot. Circulation 23: 525, POTTS WJ, SMITH S, GIBSON S: Anastomosis of the aorta to a pulmonary artery. JAMA 132: 627, PoTTs WJ, RIKER WL: Study of growth of aortic-pulmonary anastomosis. Surg Gynec Obstet 94: 358, TAUSsiG HB, CRAWFORD H, PELARGONIO S, ET AL: Ten to thirteen year followup on patients after Blalock-Taussig operation. Circulation 25: 63, KEITH JD, ROWE RD, VLAD P: Heart Disease in Infancy and Childhood. Ed 2, New York, Macmillan Co, Criteria Committee, New York Heart Association, Inc: Diseases of the Heart and Blood Vessels. Nomenclature and Criteria for Diagnosis. Ed 6, Boston, Little, Brown & Co, 1964, p MALM JR, BOWMAN FO, JAMESON AC, ET AL: An evaluation of total correction of tetralogy of Fallot. Circulation 27: 85, KIRKLIN JW, WALLACE RB, McGOON DC, ET AL: Early and and late results after intracardiac repair of tetralogy of Fallot. Ann Surg 162: 578, HALLMAN GL, COOLEY DA: Surgical treatment of tetralogy of Fallot: experience with indirect and direct techniques. J Thorac Cardiovasc Surg 46: 419, BLALOCK A, TAUSsIc HB: Surgical treatment of malformations of the heart in which there is pulmonary stenosis or pulmonary atresia. JAMA 128: 189, 1945 Circulation. Volume XLIII, February 1971

9 AORTOPULMONARY ANASTOMOSIS 11. WATERSON DJ: Treatment of Fallot's tetralogy in children under one year of age. Rozhl Chir 41: 181, COOLEY DA, HALLMAN GL: Intrapericardial aorto-right pulmonary artery anastomosis. Surg 271 Gynec Obstet 122: 184, EDWARDS WS, MOHTASHEMI M, HOLDETER WF: Ascending aorta to right pulmonary artery shunts for infants with tetralogy of Fallot. Surgery 59: 316, 1966 Notice to Authors Please list the names of all authors in the Reference section of submitted manuscripts. Circulation, Volume XLIII, Feb-rary 1971