Author + information
- Received November 19, 2001
- Revision received April 8, 2002
- Accepted April 19, 2002
- Published online July 17, 2002.
- Luc M Beauchesne, MD, FRCPC*,
- Carole A Warnes, MD, MRCP, FACC*,* (, )
- Heidi M Connolly, MD, FACC*,
- Naser M Ammash, MD, FACC*,
- A.Jamil Tajik, MD, FACC* and
- Gordon K Danielson, MD, FACC†
- ↵*Reprint requests and correspondence:
Dr. Carole A. Warnes, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905 USA.
Objectives The goal of this study was to determine the presentation and outcome of the unoperated adult with congenitally corrected transposition of the great arteries.
Background The presentation of this disorder and the outcome in unoperated adults have not been well defined.
Methods All unoperated patients ≥18 years old were evaluated for spectrum of disease, hemodynamic severity, timeliness of diagnosis and referral, and outcome.
Results Forty-four patients aged 20 to 79 years (mean, 44) were followed up to 144 months. In 29 (66%), the correct diagnosis was first made at age ≥18 years; the diagnosis was missed in seven of these patients in a prior cardiology consultation, despite cardiac imaging. Systemic atrioventricular valve (SAVV) regurgitation (grade ≥3/4) was noted in 26 patients (59%). Thirty (68%) had surgical intervention, including SAVV replacement in all, with no early mortality. Preoperatively, this subset had significant dysfunction of the systemic ventricle (SV) (ejection fraction [EF], 40 ± 10%), and most had advanced symptoms (25 with ability index ≥2/4). In 16 (53%), SAVV regurgitation ≥3/4 and ventricular dysfunction had been documented for >6 months. The mean EF of the SV decreased significantly postoperatively (34 ± 11%, p = 0.006). Four patients (13%) eventually required cardiac transplantation. Poor preoperative EF of the SV predicted eventual need for transplantation (p = 0.001).
Conclusions Patients with unoperated congenitally corrected transposition of the great arteries are often misdiagnosed in adulthood and are referred late despite symptomatic SAVV regurgitation and significant SV dysfunction. Although excellent early surgical results can be achieved, significant residual dysfunction of the SV is common.
Congenitally corrected transposition of the great arteries (CTGA) is a complex congenital cardiac anomaly with a wide spectrum of morphologic features and clinical profiles (1,2). For all cases, the shared underlying abnormality consists of atrioventricular and ventriculoarterial discordance. The morphologic right ventricle functions as the systemic ventricle (SV), whereas the morphologic left ventricle functions as the pulmonary ventricle (PV). The atrioventricular valve connected to the SV is morphologically tricuspid and may also be designated as the systemic atrioventricular valve (SAVV). The atrioventricular valve connected to the PV is morphologically mitral and may be designated as the pulmonary atrioventricular valve (PAVV). The nature and extent of associated anomalies, including SAVV regurgitation, dictate the need for and timing of surgical intervention in the pediatric population (3). Long-term outcomes have been described in this cohort as they reach adulthood (3–5). In a proportion of patients, the hemodynamics do not require surgical attention during childhood, and, in some, the correct diagnosis is not established until adulthood. We sought to characterize the clinical characteristics of the unoperated adult with CTGA referred to a large adult congenital heart disease clinic and to describe the early and midterm outcomes in those undergoing subsequent surgical intervention.
We searched the Mayo Clinic adult congenital heart disease clinic database from 1986 to 2000 for all CTGA patients ≥18 years old with two good-sized ventricles and no prior cardiac surgery. Details regarding initial symptoms, functional status and management before referral to the adult congenital heart disease clinic were obtained through chart review. Surgical notes were reviewed, as were imaging studies, with emphasis on the function of the SV preoperatively and postoperatively. When multiple postoperative determinations of ejection fraction (EF) were made at various times, we chose the study closest to 12 months postoperatively to allow optimal ventricular recovery. The EF was determined echocardiographically (6). Grading of SAVV regurgitation was semiquantitative (1/4 mild, 2/4 moderate, 3/4 moderately severe, 4/4 severe). Ability index was graded with the Warnes-Somerville index, which emphasizes limitations in daily activity (7). Functional capacity on the treadmill using time achieved on the Bruce protocol was expressed as a percent of expected when compared with the predicted value for gender, age and body size (8). A patient was deemed to have been referred late if both of the following two criteria were met: 1) documented SAVV regurgitation ≥3/4 for more than six months, and 2) documented symptoms of heart failure or SV EF <45% for more than six months. Questionnaires were sent to selected patients when initial retrieval of data from the chart review was deemed insufficient or was not available in the last year. The study protocol and questionnaire were reviewed and approved by the Institutional Review Board.
Mean, median, SD and range were calculated for continuous variables. Frequencies were derived for categorical variables. Unpaired continuous variables were compared by the Mann-Whitney Utest. Paired continuous variables were analyzed with the Wilcoxon test. Categorical variables were compared by the Fisher exact test. Prespecified variables were analyzed by proportional hazards regression analysis as predictors of need for subsequent cardiac transplantation and included age at surgery. All calculated p values were two-sided, and p values less than 0.05 were considered statistically significant. Statistical analysis was performed with JMP 4.04 (SAS Institute Inc., Cary, North Carolina).
From our database we identified 73 subjects who fulfilled all of the following criteria: 1) diagnosis of CTGA with two good-sized ventricles, 2) seen at least once during the 1986 to 2000 period, and 3) ≥18 years old at the time of the initial visit. From this group, 44 patients (22 of them men; mean age, 44 years; range, 20 to 79 years) had no history of cardiac surgery at the time of the initial visit. All were referred to our clinic from another consultant (cardiologist or internist) for further evaluation. Recent (<1 year) follow-up data were available in all cases. The mean follow-up was 53 months (range, two to 144 months). The correct diagnosis of CTGA was made in adult life (age ≥18 years) in 29 of the 44 patients (66%), five (17%) of whom were ≥60 years of age at the time of diagnosis. In seven (24%) of the 29, the presence of a congenital cardiac anomaly was not recognized despite prior cardiology consultations elsewhere, which included in all at least one cardiac imaging study (either echocardiogram or catheterization or both). Of the 44 patients, 30 had surgical intervention. Fourteen have remained unoperated (Fig. 1).
Initial presentation data
The presence of typical associated lesions (defined as PV outflow obstruction, ventricular septal defect or morphologically abnormal SAVV) was common, having been found in 22 of the 44 patients (50%) (Table 1). Systemic atrioventricular valve regurgitation (grade ≥3/4) was present in 26 patients (59%). In 16 of the 26 patients, the valve was morphologically abnormal (12 apically displaced, four not apically displaced but dysplastic). Fourteen had PV outflow tract stenosis, three with peak gradients ≥70 mm Hg. In two of the three patients, the outflow obstruction was primarily related to a ventricular septal aneurysm projecting into the outflow tract. In the remaining patient, obstruction was due to a duplicated SAVV crossing the ventricular septal defect.
The presenting symptoms varied; the most common primary complaint was dyspnea, in 20 patients. No patient was cyanosed. The ability index at presentation was 1 in 11 patients (25%), 2 in 23 patients (53%), 3 in 9 patients (21%) and 4 in 1 patient (2%). The mean exercise capacity in 27 patients who had exercise stress testing was 79 ± 26% of predicted (range, 32% to 122%). The mean EF of the SV at initial presentation was 41 ± 10% (range, 23 to 65).
Thirty patients (68%) underwent surgical intervention (median age, 44 years; range, 20 to 75; median follow-up time after surgery was 51 months; range, 5 to 143). Patients requiring surgery had larger cardiothoracic ratios on chest radiographs and tended to have lower EF of the SV, the majority having ≥3/4 SAVV regurgitation (Table 2). Thirteen of the 30 patients requiring surgery were deemed to be too sick to undergo exercise stress testing at the initial evaluation. In 16 of 30 patients (53%), referral for surgical intervention was deemed late (patient known to have both SAVV regurgitation ≥3/4 and clinical ventricular dysfunction for more than six months). The median time to surgery from initial referral was one month (range, 1 to 47 months). All patients underwent SAVV replacement as part of the surgical procedure, and 20 had other concomitant cardiac repair (Table 3).
One patient had double-switch surgery (Mustard and Rastelli procedure) and SAVV replacement at age 32. He presented with severe PV outflow obstruction, a large ventricular septal defect and severe SAVV regurgitation. The preoperative EF of his SV was 33%; the EF of the SV was 25% 18 months after the procedure.
There were no early postoperative deaths. Two patients required implantation of a permanent pacemaker for heart block that occurred postoperatively (<30 days). Three patients had internal defibrillators placed: one for nonsustained ventricular tachycardia in the setting of a poorly functioning SV one week after SAVV replacement, one for ventricular fibrillation arrest two months after SAVV replacement and one for sustained ventricular tachycardia 15 years after SAVV replacement. The mean follow-up of the postoperative group was 51 months. Four patients eventually required orthotopic heart transplantation (see the following text). One patient died of endometrial carcinoma nine years after SAVV replacement.
The mean preoperative EF of the SV was 40 ± 10%, range, 23 to 65. The mean postoperative EF of the SV was 34 ± 11% (n = 29, range, 15 to 52, p = 0.006; median time of the study after surgery was 11 months) (Fig. 2). There was no significant difference in the use of medications (angiotensin-converting enzyme inhibitor, angiotensin II receptor blocker, beta-adrenergic blocking agent) that would have an impact on ventricular performance in the patients at the time of the preoperative versus the postoperative echocardiogram (preoperative 21/30 [70%] vs. postoperative 18/30 [60%], p = NS).
Need for orthotopic heart transplantation
Of the 30 patients treated surgically, four eventually required orthotopic heart transplantation because of failure of the SV (median time to transplantation after initial surgery was 56 months; range, 24 to 118; mean follow-up time, 51 months). Poor preoperative EF of the SV was the only variable that predicted eventual need for heart transplantation (Table 4).
No surgery was performed in 14 patients (median age, 43 years; range, 20 to 79). The mean EF of the SV at presentation was 43 ± 8%; range, 25 to 58. One patient presented to the clinic at age 62 with severe SV dysfunction, an EF of 25% and severe SAVV regurgitation. His SV dysfunction was thought to preclude a good long-term result after SAVV replacement, and so he was evaluated for cardiac transplantation. He was lost to follow-up, and died suddenly 12 months later. No autopsy was performed. Two patients eventually required permanent pacemaker insertion for chronotropic incompetence.
The adult with CTGA can present in various ways (9–11). A number of these patients have had prior surgical repair in childhood for associated lesions that were hemodynamically significant. Some were correctly diagnosed in childhood but did not require surgical intervention. A subset of patients is correctly diagnosed for the first time only in adulthood. The last two groups form the cohort of patients with unoperated CTGA who are seen in the adult congenital heart disease clinic. This is the first report to focus specifically on this subset of patients with CTGA. Our data suggest that these patients present unique diagnostic and therapeutic challenges.
In 66% of the patients in our cohort, the initial diagnosis of CTGA was first made in adulthood; 17% of them were 60 years or older at the time of diagnosis. This high proportion of patients with delayed diagnoses can be partly explained by: 1) the unoperated subset of patients with CTGA is more likely to have been asymptomatic during childhood and did not require medical attention, and 2) two-dimensional echocardiography not having been available in the era involved. The modes of clinical presentation were varied and were similar to those in prior reports (11,12). The majority presented with symptoms related to SAVV regurgitation, failing SV function or conduction disease. In some, the diagnosis was made incidentally when electrocardiography, chest radiography or echocardiography was performed for other reasons (e.g., atypical chest pain). In 24%, the diagnosis had been missed at the time of a prior cardiology consultation, despite the use in all cases of cardiac imaging (echocardiogram or catheterization or both). A common scenario was the patient with dextrocardia who was thought to have simple situs inversus totalis and was not recognized as having CTGA. Because it is a relatively rare lesion, CTGA may not be readily recognized by the adult cardiologist who is untrained in congenital heart disease.
SAVV regurgitation and SV dysfunction
The most common hemodynamic problem encountered in this cohort was SAVV regurgitation in the setting of impaired SV function. Of the 68% of patients who required surgical intervention, all needed SAVV replacement as part of the surgical repair. The relation between SAVV regurgitation and SV dysfunction in CTGA is complex and is not completely understood (9,10,13–15). In the majority of patients with CTGA, the SAVV is morphologically abnormal (16). With time, the valve deteriorates, and there is increasing regurgitation (11). This chronic volume load on the SV, in turn, leads to annular and ventricular dilation, resulting in malcoaptation and worsening regurgitation (17). In a study with a mean follow-up of 20 years (13), the presence of a morphologically abnormal SAVV was the only predictor of severe SAVV regurgitation, and severe SAVV regurgitation was the only independent predictor of long-term survival in both operated and unoperated patients with CTGA.
Systemic ventricle dysfunction in the adult with CTGA is common, is age related and occurs more likely in the presence of associated anomalies, history of heart block or history of prior surgical intervention (9–11,18,19). Some have proposed that the SV may not be intrinsically suited to function as a long-term systemic pump in CTGA (18). However, there have been occasional reports of elderly patients (7th or 8th decade) with essentially normal function of the SV, usually in the absence of associated lesions. Although it is difficult to determine whether ventricular dysfunction or SAVV regurgitation is the initial culprit, evidence suggests that, in the absence of associated lesions, primary SV failure is uncommon but is a frequent sequela to SAVV regurgitation (13). Although unproven, it has been our experience that the degree of SAVV regurgitation in CTGA may be underestimated by echocardiography, and its presence should be aggressively sought, if necessary with cardiac catheterization, especially in patients with deteriorating SV or progressive enlargement of the cardiothoracic ratio on chest radiographs. Other proposed mechanisms of failing of the SV have included coronary perfusion mismatch (20), volume load from prior shunts (14)and inadequate myocardial protection at the time of prior surgery.
Additional challenges include the difficulties of defining normal function of the SV as a systemic pump in CTGA. Traditionally, EF has been used, and reported values have varied, depending on the technique used and the presence or absence of the above-mentioned variables in the population studied. In a study involving a small group of young, asymptomatic patients with no associated lesions, the mean EF of the SV was 48 ± 4% by radionuclide angiocardiography, which was comparable to the EF of a nontransposed right ventricle (21). Recently, Fredriksen and colleagues (22), using the same technique in a different cohort consisting of adults with CTGA, many of whom had a history of surgical intervention, reported a mean increase of the EF of the SV with exercise of only 2%, which was less than the expected 5% (23).
Timing of surgical intervention
The most appropriate timing of SAVV replacement in the CTGA patient remains uncertain. The SV seems to tolerate the volume load of SAVV regurgitation less well than the morphologic left ventricle does with mitral regurgitation. In view of this, the threshold for surgical intervention may be lower. In a series from the Mayo Clinic (24), replacement of the SAVV when the EF of the SV was less than 44% was associated with poor early and late outcome, whereas all patients with a preoperative EF greater than 44% survived operation and lived over mid- to long-term follow-up. Current guidelines have suggested SAVV replacement in CTGA when SAVV regurgitation is moderately severe or severe, especially if there are signs of ventricular dysfunction. In our cohort, the subset of surgical patients had a preoperative mean EF of the SV of 39%, which is markedly depressed considering that the majority (80%) had a large volume load (SAVV regurgitation ≥3/4).
In 53% of the patients, the referral for surgery was inappropriately delayed. We suspect that this delay was due to difficulties in assessing SV performance, to underestimating the degree of SAVV regurgitation and to lack of appreciation of the vulnerability of the SV in CTGA. Although the patients did well, with no early mortality in this series with mid-term results, the relatively poor preoperative EF of the SV suggests that in many patients SV dysfunction might progressively deteriorate over longer follow-up (24). Indeed, four patients eventually required heart transplantation, and the low preoperative EF of the SV was the only predictive variable for this event. At our institution, one of the clinical variables used to determine optimal timing of SAVV replacement has been a limitation in exercise capacity on stress testing. It has been our experience that patients with adult congenital heart disease tend to underestimate their functional limitations and that, in many, objective evaluation with exercise stress testing may document unexpected impairment in exercise capacity. Our data did not show that functional capacity on exercise stress testing was statistically different between the surgical group and the nonsurgical patients; nor did it predict need of future transplantation. This finding was partly related to the bias introduced because 43% of patients in the surgical group were too ill to undergo testing.
Limitations of this study include referral bias, small numbers and lack of generalization to other centers. Our cohort probably does not represent the whole population of adults with unoperated CTGA in the community because the patients with poor hemodynamics were more likely to be referred for further evaluation and consideration for surgery. This limits generalization of our data. The small number of patients and the infrequency of morbid end points precluded multivariate analysis and underpowered certain variables such as ability index and cardiothoracic ratio, which we believe may be of prognostic value. Although our early surgical mortality was zero, this may not be generalizable to other centers with less experience in the management of these complex patients.
The unoperated adult with CTGA is often diagnosed late in life, and the condition, not uncommonly, is unrecognized at an initial cardiology consultation. Systemic atrioventricular valve regurgitation is the dominant hemodynamic lesion in this group. At the time of referral for surgical repair, the majority of these patients have significant SV dysfunction with advanced symptoms. Although excellent early surgical results can be achieved, residual impairment of the SV is common and may eventually necessitate cardiac transplantation.
☆ Dr. Beauchesne is currently affiliated with the Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
- congenitally corrected transposition of the great arteries
- ejection fraction
- pulmonary atrioventricular valve
- pulmonary ventricle
- systemic atrioventricular valve
- systemic ventricle
- Received November 19, 2001.
- Revision received April 8, 2002.
- Accepted April 19, 2002.
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