microcomputer using specially designed software (Apple. Canada, Toronto, Canada). For late results in all patients operated on before Jan- uary 1981, records ...
Results with the Mustard Operation in Simple Transposition of the Great Arteries 1963-1985
GEORGE A. TRUSLER, M.D., WILLIAM G. WILLIAMS, M.D., KIM F. DUNCAN, M.D., PETER S. HESSLEIN, M.D., LEE N. BENSON, M.D., ROBERT M. FREEDOM, M.D., TERUO IZUKAWA, M.D., and PETER M. OLLEY, M.D.
From May 1963 to December 1985, 329 infants and children underwent repair of simple transposition of the great arteries (TGA) using Mustard's technique. To assess improvement, the patients were separated into two groups by date of operation: Group I, May 1963 to December 1973 (N = 106), and Group II, January 1974 to December 1985 (N = 223). The operative mortality was 11 (10.4%) in Group I and two (0.9%) in Group II. The 10-year actuarial survival rate was 73.4% in Group I and 93.7% in Group II. Baffle complications, similar in both groups, were identified in 81 patients; 19 were major, causing death or requiring reoperation. By latest electrocardiogram, 21 of 45 (46.7%) of Group I patients and 129 of 180 (71.7%) of Group II patients were in normal sinus rhythm. Late ambulatory electrocardiography, however, revealed that a majority of patients had sinus node dysfunction or other dysrhythmias. Right ventricular (RV) angiography revealed definite diminution of RV contractility in 14 (11%) of 126 children. At late follow-up, 113 of 148 (76%) children were in New York Heart Association (NYHA) Class I and 35 of 148 (24%) were in NYHA Class II. Thirty-five (21%) patients were on cardiac medication chiefly for dysrhythmia management. There has been significant improvement in the early and late mortality with the Mustard operation, and serious baffle complications are infrequent. Dysrhythmias continue to be a major problem but the surviving patients are clinically well and relatively few have significant RV dysfunction.
W M , ' UCH HAS CHANGED in the management of complete transposition of the great arteries (TGA) over the last 25 years. After Mustard' first performed his atrial repair in May 1963, there was an immediate awakening of interest in the treatment of TGA. Eventually this lead to a re-examination of other operations, and it was soon found that the Senning2 atrial repair could produce equally satisfactory results.3 Reprint requests: George A. Trusler, M.D., Suite 1525, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8. Presented at the 107th Annual Meeting of The American Surgical Association, Palm Beach, Florida, April 21-23, 1987. Submitted for publication: April 24, 1987.
251
From the Divisions of Cardiovascular Surgery and
Cardiology, The Hospital for Sick Children, and the Departments of Surgery and Pediatrics, The University of Toronto, Toronto, Ontario, Canada
Later, success was attained with arterial repair, although initially with high mortality.4 As techniques improved and mortality decreased, arterial repair came to be the preferred treatment in children with TGA and associated ventricular septal defect (VSD).5'6 Recently arterial repair has been applied to simple TGA in neonates and results are sufficiently competitive to warrant a thorough review of the Mustard procedure.7-9
Patients and Methods From May 1963 to December 1985, at the Hospital for Sick Children in Toronto, 329 infants and children underwent repair of simple TGA using Mustard's technique. This includes children with small inconsequential VSDs or a degree of left ventricular outflow tract obstruction not needing treatment. To assess improvement in results with time, the patients were divided into two groups, those who had repair during the first decade from May 1963 to December 1973 (Group I, N = 106) and those who had repair in the subsequent 12 years from January 1974 to December 1985 (Group II, N = 223) (Table 1). In the early years, 49% of infants received temporary palliation with a Blalock-Hanlon surgical septectomy. This practice has continued with a higher proportion of atrial septectomies in infants seen initially at our institution than those referred secondarily. The elective age for repair has decreased through the years so that now most Mustard procedures are performed between 6 and 12 months of age. Originally all repairs were done with cardiopulmonary bypass, but starting in 1972, deep hypothermia and
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TABLE 1. Mustard Repair ofSimple Transposition ofthe Great Arteries
Number of patients Age at operation Mean Previous atrial septectomy Early deaths Late deaths
Group I 1963-1973
Group II 1974-1985
106 27 days-161 mos 37.5 mos 52 (49.1%) 11 (10.4%) 21 (22.1%)
223 2-131 mos 14.25 mos 110 (49.3%) 2(0.9%) 10 (4.5%)
circulatory arrest were used for infants less than 8-10 kg of body weight, which now includes most patients. Since 1976, we have attempted to minimize intraoperative myocardial ischemic damage by giving cold cardioplegia, at first crystalloid and later blood cardioplegia. In addition, the ventricular myocardium has been kept hypothermic with a cold pericardial bath, now replaced by a special cooling jacket. There have been a few modifications of the original technique. To excise the atrial septum, an incision is first made from the middle of the foramen ovale to the midpoint of the superior vena caval (SVC) orifice. The ridge of tissue medial to the cut is preserved for its potential to allow conduction from the sinoatrial (SA) node to the atrioventricular (AV) node and also to reduce the danger of cutting the artery to the SA node. An earlier study indicated a significant increase in the incidence of sinus rhythm when this ridge of tissue was preserved.'0 All septum lateral (rightward) to the cut is excised. The coronary sinus is cut back and often a small portion of its wall is carefully excised to enlarge the inferior vena caval (IVC) channel. All large raw areas are oversewn to reduce stricture formation and adhesions to the baffle. Cardiac catheterization was performed after operation in 126 children (Group I, N = 45; Group II, N = 81) with simple TGA to assess baffle problems, as well as tricuspid valve and right ventricular (RV) function. Cardiac rhythm was assessed primarily by serial electrocardiography, (EKG) but we examined all ambulatory monitor ("Holter") recordings and programmed stimulation electrophysiological studies (EPS) performed on these children. Holter recordings were obTABLE 2. Early Mortality*
Group I
(N = 106) Deaths Myocardial failure Dysrhythmia Cerebral injury
Bleeding Air embolism
*p
