Congenitally Corrected Transposition Treatment & Management

Connelly et al reported infective endocarditis in as many as 11% of a 52-patient series. ^[15] In most cases, antibiotic prophylaxis is indicated according to the recommendations of the American Heart Association.

Management of heart failure may entail use of diuretic drugs, digitalis, beta-blockers, and/or angiotensin-converting enzyme (ACE) inhibitor therapy. All are helpful for symptomatic therapy in particular individuals, but none are demonstrated to improve mortality rates in patients with congenital heart disease. In fact, a systematic review of medical therapy for systemic right ventricles for the 2018 AHA/ACC Guideline for the Management of Adults with Congenital Heart disease did not show any evidence of benefit of medical therapy (beta blockers, ACE inhibitors, ARBs, and aldosterone antagonists) in patients with systemic right ventricles. ^[16]

It is tempting to suggest that established treatment outcomes for severe LV dysfunction (ACE inhibitor, beta-blocker, nitrate, hydralazine, aldosterone antagonist) would have similar effects in patients with RV failure in the setting of congenitally corrected transposition of the great arteries; however, little evidence-based data is available to support improvements in cardiac outcomes or total mortality as was observed when treating LV systolic dysfunction. Furthermore, caution should be used with administration of beta-blockers, as complete heart block may be precipitated in these patients with known conduction system abnormalities. Ultimately, patients with failing systemic ventricular function, if good candidates, may best be served by cardiac transplantation.

Surgery is recommended only for symptomatic associated lesions and when significant hemodynamic benefit is expected.

Common postoperative complications include complete heart block and progressive tricuspid regurgitation, even when these anatomic structures are not manipulated directly.

The altered location of a fragile conduction system and the mirror image coronary anatomy may complicate surgical repair. The right-sided coronary artery often divides into the anterior descending and circumflex branches, which supply the morphological left ventricle. This complicates placement of a conduit in patients to relieve pulmonic stenosis.

In a study of 62 adults with congenitally corrected transposition of the great arteries (ccTGA), Helsen and colleagues found that native or surgically induced pulmonary outflow tract obstruction (POTO) was associated with an improved event-free survival. Event-free survival was defined as the composite of all-cause mortality, heart transplantation, or congestive heart failure. In the presence of POTO, the mean progression-free interval for the composite endpoint increased from 11.2 years to 18.1 years (P=0.035). ^[17]

Ventricular septal defect closure is generally performed when symptoms of CHF or failure to thrive do not respond to medical therapy or when pulmonary vascular pressures are increasing. Operative mortality rate among 15 patients with ventricular septal defect reported by Termignon et al ^[18] was 13%, with 33% requiring permanent pacemaker implantation for complete heart block. Two patients had late deaths and 6 required reoperation for tricuspid valve replacement. Of note, ventricular septal defect closure may exacerbate systemic AV valve (morphologic tricuspid valve) regurgitation due to septal shift and distortion of the AV valve annulus.

Tricuspid valve replacement can be performed for severe tricuspid incompetence. Repair of the dysplastic or displaced valve is not usually feasible. Tricuspid valve replacement should also be considered when severity is more than grade 2/4 and other intracardiac lesions are being corrected. Replacement of the tricuspid valve is recommended for symptomatic (class I) or asymptomatic (class IIa) adults with CCTGA and severe tricudpid regurgitation, if they have preserved or only mildly reduced systemic ventricular function. ^[12]

Switch procedures attempt to correct the underlying malformation anatomically, trying to minimize the risk of heart block or tricuspid incompetence. Note the following:

• The atrial and ventricular double switch procedure is performed when pulmonic stenosis and a large ventricular septal defect are present. ^[19] Feasibility of the repair depends on the location of the ventricular septal defect. The repair requires proximity of a ventricular septal defect to the aorta. Chordal malattachments or deformation of the mitral valve inhibiting support of systemic pressures may exclude this option.

• The Rastelli procedure, originally described by Gian Carlo Rastelli in 1969, for patients with D-transposition of the great arteries, large ventricular septal defect, and naturally occurring pulmonary outflow obstruction involves routing the left ventricle to the aorta via a prosthetic baffle through the ventricular septal defect into the right ventricle to the aortic valve and placing a conduit from the right ventricle to the pulmonary artery bifurcation. In patients with moderate pulmonary stenosis, self-palliation has occurred and infants can survive for many years without intervention. ^[20]

  Post-Rastelli repair with left ventricle to aortic baffle through a ventriculoseptal defect (VSD) complicated by subaortic stenosis.

  View Media Gallery

• The atrial switch for L-transposition takes the form of the Senning or Mustard procedure with additional repair of any ventricular septal defect. These procedures involve intra-atrial baffles to route venous blood toward the right ventricle and pulmonary artery, and oxygenated blood from the pulmonary veins into the left ventricle and out to the body. The Senning procedure is technically advanced to better preserve intrinsic AV nodal function. The atrial switch is coupled either with an arterial switch (part of the Double Switch) or a Rastelli procedure. The right ventricle and tricuspid valve will become subpulmonic at this point.

• The arterial switch operation is the most current procedure available, generally performed within 2 weeks of birth. In this procedure, the left ventricle must have tolerated near-systemic pressures prior to the switch. Pulmonary artery banding prior to a definitive repair can prepare the ventricle if a sufficient ventricular septal defect is not present; however, based on results from repair of complete transposition of the great arteries, long-term outcome after atrial switch is a concern. Late complications include atrial arrhythmias and vena cava or pulmonary venous obstruction.

In a study of 52 patients reported by Termignon et al, ^[18] the operative mortality rate of a classic repair of congenitally corrected transposition of the great arteries and ventricular septal defect was 16% and the rate of complete heart block was 24% after the repair. Six additional late deaths and 5 patients who required reoperation for tricuspid valve replacement were also listed. Survival rates were 83% at 1 year and 55% at 5 years after the repair.

Early pacemaker placement is recommended in the setting of complete heart block either during or after surgical intervention or if any significant associated defect, such as cardiomegaly, decreased right ventricular function, symptomatic bradycardia, or heart failure, is present. Unfortunately, transvenous pacemaker implantation may also precipitate worsening AV valve regurgitation and deterioration of systemic ventricular performance by altering position of the ventricular septum during pacing, resulting in incomplete systolic coaptation of the tricuspid valve and, hence, worsening regurgitation. ^[21]

In a retrospective review of 53 patients, Hofferberth et al found that late-onset systemic ventricular dysfunction is a major complication associated with univentricular pacing in patients with congenitally corrected transposition of the great arteries (ccTGA). Patients with ccTGA who develop heart block should undergo primary biventricular pacing, which prevents late systemic ventricular dysfunction. Preemptive placement of biventricular pacing leads at the time of anatomical repair or another permanent palliative procedure will facilitate later biventricular pacing if heart block develops. ^[22]

Percutaneous pulmonary valvuloplasty is not recommended in patients with transposition of the great vessels because of expected complete heart block.

Patients with congenitally corrected transposition should be managed and seen regularly by cardiologists with expertise and training in congenital heart disease. Furthermore, patients referred for cardiac catheterization, electrophysiologic procedures, or percutaneous and/or surgical procedures should be referred to centers with expertise in congenital heart disease.

The reduced ability of the right ventricle to support systemic pressure and associated anomalies limit activity. The 1994 Bethesda Conference included patients with congenitally corrected transposition of the great vessels, and specific recommendations to limit activity were not made. Individual assessment should include serial evaluations of right ventricular function.

Serial echocardiograms to monitor right ventricular (ie, systemic ventricular) size and function, and tricuspid (systemic AV) valve regurgitation can help to time operative repair and assess effects of medical intervention. Data are emerging using right ventricular radionuclide angiography and magnetic resonance angiography for both perfusion and function assessments. Multiple gated acquisition (MUGA) scans can also accurately describe right ventricular function and dimension.

• Guidelines for the Clinical Application of Echocardiography by an ACC/AHA Task Force suggest that class I indications for follow-up echocardiograms in patients with known congenital heart disease include any change in clinical findings, any uncertainty of the original diagnosis or of the structural abnormalities or hemodynamics, or periodic monitoring for those whose ventricular function and AV valve regurgitation must be followed. ^[23]

• The timing of periodic monitoring is not specified. Most centers monitor patients with serial echocardiography; more frequent examinations are warranted for any change in clinical status.

• Dobutamine stress echocardiography may also be helpful. In asymptomatic children after arterial switch surgery, baseline left ventricular function is often mildly impaired with reversible areas of ischemia revealed, despite normal coronary perfusion.

Depending on the functional status and level of right ventricular dysfunction, adult patients with CCTGA should follow up with an outpatient ACHD cardiologist every 3-12 months. ECG and echocardiograms should be obtained yearly. Holter monitors, Cardiac MRIs, and exercise testing can also be obtained at regular intervals ranging from 12-60 months depending on each individual’s functional status and symptoms. ^[12]