Re-intervention long after Intracardiac Repair for Congenital Heart Disease

Assessment of Ventricular Function after Right Ventricular Outflow Tract Repair of Congenital Heart Disease

Thomas P. Graham, Jr, MD

Children’s Hospital at Vanderbilt,
Nashville, USA

An increasing number of patients have residual abnormalities of ventricular function and cardiovascular performance after right ventricular outflow tract (RVOT) repair. In his keynote lecture, Dr. Thomas P. Graham, Jr, Vanderbilt Children’s Hospital, discussed methods for assessing ventricular function in these patients.

Hemodynamic impairments that might persist after RVOT surgery for tetralogy of Fallot (TF) include pulmonary valvular regurgitation, residual RVOT obstruction, pulmonary artery stenosis, pulmonary hypertension, left heart failure, and RV dysfunction. Patients with RVOT defects may experience tetralogy symptoms with pulmonary atresia, transposition of the great arteries (TGA) with ventricular septal defect (VSD) or pulmonary stenosis (PS), and truncus arteriosus.

Radionuclide studies of RV function after TF repair have shown that many patients show a decrease in RV function over time. Other studies have shown that patients who had previous tetralogy repair had pulmonary valve regurgitation necessitating pulmonary valve replacement (PVR) as adults. Even after PVR, ejection fraction (EF) did not improve in many of these patients, suggesting that PVR had been delayed too long.

Cardiac magnetic resonance imaging (MRI) is a newer technique used to assess cardiac anatomy, right and left ventricular volumes and mass, EF, valvular regurgitation, pulmonary artery abnormalities, and coronary anomalies. In a large study, 100 consecutive long-term survivors of TF repair were evaluated by cardiac MRI. The MRI measurements were correlated with the patients’ clinical status. In the univariate analysis, RVEF and LVEF were most strongly associated with poor clinical status (Figure 1). Graham noted that the patients in this study were operated on late and had poor myocardial protection, which probably explains the poor LVEF.

RV volume was quantified with MRI to determine optimal timing for PVR in 17 adults after TF repair. RV end-diastolic volume (RVEDV) normalized (<108 mL/m²) in 9 of 17 patients post-PVR. Only those patients whose pre-PVR RVEDV was <170 mL/m² were normalized. Patients with RV end-systolic volume (RVESV) >85 mL/m² did not achieve normal RVESV (<47 mL/m²). LVEF was unchanged in the patients after PVR.

RV dysfunction in patients with RVOTO repair may be associated with annular or valve obstruction, conduit or homograft obstruction, pulmonary obstruction, pulmonary hypertension, or valvular regurgitation. Ventricular fibrosis diagnosed by cardiac MRI with late gadolinium enhancement (LGE) can be an indicator of poor clinical outcome after TF repair. RV and LV LGE is common after TF repair, and is related to older age, more symptoms, increased atrial natriuretic peptide (ANP), decreased exercise ability, increased RVESV, decreased RVEF, and clinical arrhythmia.

A study to determine timing for reoperation in patients after RVOT repair looked at 17 asymptomatic and 14 symptomatic patients. The symptomatic group had reoperation. RV stress index was estimated as RV peak pressure x volume/mass ratio. RV systolic pressure, volume, mass index, and stress index were higher in patients with symptoms. The volume/mass ratio was lower and the EF was lower. An inverse relationship was found between the RV stress index and EF in the control and NYHA class I groups. All patients whose RVEF decreased to <95% confidence limit for stress index had symptoms of RV failure. Their RVEF did not improve to normal after PVR. The authors concluded that excessive wall stress contributes to impaired RV performance and the RV stress-RVEF relation can be useful in assessing RV function.

Dr. Graham concluded that cardiac MRI is very useful for assessing anatomy, volume and mass, pump function, valvular regurgitation, and fibrosis estimates. Exercise studies with VO2 also are useful. BNP levels may be useful in some patients.

Future challenges include understanding the mechanisms whereby some right ventricles can perform extremely well despite severe pressure and volume overload. Further strategies are needed to preserve and enhance RV function and to improve myocardial blood flow. Studies are needed to determine whether pharmacologic agents that are effective in LV dysfunction are also effective in the RV and to develop specific targeted therapy.

Reoperation at RVOT Long after Definitive Repair of Congenital Heart Disease

Toru Ishizaka

National Cardiovascular Center
Suita, Japan

After right ventricular outflow tract reconstruction (RVOTR) patients often develop residual stenosis or pulmonary regurgitation (PR), requiring reintervention. The objective of this study, presented by Dr. Ishizaka, Osaka, Japan, was to analyze results of reoperation at the RVOT after previous biventricular repair (BVR) for congenital heart disease.

A total of 147 patients underwent reoperation more than one year after previous BVR. Of these, 22 patients had a second reoperation and three patients had a third reoperation, for a total of 172 reoperations. The average patient age at initial BVR was 4.3 years. The previous BVR was external conduit repair in 102 patients and non-conduit repair in 45 patients. The interval after the initial repair was 8 ± 3.7 years.

Indications for reoperation were RVOT obstruction (RVOTO) (n=159), infective endocarditis (n=6), AR or LVOTO with mild pulmonary stenosis (PS) or PR (n=4), severe PR with reduced RV function (n=2), and coronary artery compression (n=1).

Figure 1 shows the overall results. Overall survival after the first reoperation was 94.8% at 10 years and 93.4% at 15 years (Figure 2). Univariate risk analysis revealed that external conduit repair (ECR) at initial BVR (p =0.0001), use of conduit at reoperation (p =0.001), and younger age at reoperation (p =0.05) were significant risk factors for reoperation.

Of 102 patients reoperated for conduit stenosis, a patch was used in 52, with xeno-pericardium (n=47) and GoreTex (n=5). Conduit replacement was done in 50 patients with pulmonary hypertension (PH), peripheral PS, or poor RV function, using VPR (n=26), VGR (n=13), and others (n=10). Patients who received the patch had better results than those with conduit replacement, although the patient cohort was different in the two groups.

Cardiac catheterization before and one year after reoperation showed that RV pressure (RVP) and RV ejection fraction (RVEF) improved, and RV end-diastolic volume (RDEV%) remained normal; 94% of survivors had NYHA class I or II after reoperation (Figure 3).

Ishizaka concluded that the overall results of reoperation were favorable with low morbidity and mortality. Severe PR with RV dysfunction is a rare indication for reoperation at his center because of the policy to minimize right ventriculotomy and use a flared distal conduit at initial BVR. Optimal selection of the patch method or conduit replacement for conduit stenosis resulted in well-maintained RV function with normal RV volume after reoperation. To prolong or avoid further re-intervention, better options for re-RVOTR need to be developed.

Re-Intervention Long after Intracardiac Repair for Congenital Heart Disease

Munetaka Masuda

Kyushu University
Graduate School of Medicine
Fukuoka, Japan

The incidence of re-intervention after surgical repair for tetralogy of Fallot (TOF) and double outlet of right ventricle (DORV) has been increasing. Dr. Munetaka Masuda, Kyushu University, presented results of a study designed to clarify indications for re-intervention in patients with residual disease and sequelae after surgery for TOF or DORV.

A total of 41 re-intervention procedures were performed in 37 patients who underwent surgical repair of TOF or DORV (subaortic ventricular septal defect [VSD] with pulmonary stenosis [PS]) at least five years earlier. After re-intervention, patients were followed for a mean of 17 years (6 to 36 years).

Patients included in the study had either residual disease or sequelae after the initial intervention. Two patients underwent ablation for supraventricular arrhythmia 33 years after the initial repair. Eight patients had re-intervention for ventricular arrhythmia at intervals ranging from 9 to 36 years after the initial intervention (Figure 1). Re-interventions included ablation (n=2), pulmonary valve replacement (PVR) (n=3), and PVR plus cryoablation (n=3). At the last follow-up, two patients were still taking antiarrhythmic drugs and six were medication-free.

Two patients had aortic valve replacement for aortic valve regurgitation that occurred 21 and 22 years after the initial repair. One patient died seven years later from sepsis. A patient with mitral valve regurgitation had mitral valve plasty and VSD closure 27 years after the initial surgery. VSD closure was done in three patients at 18, 19, and 26 years after initial surgery.

Seven patients required re-intervention by right ventricular outflow tract repair (RVOTR) (n=7) and stent (n=1) for residual PS 6 to 22 years after the first repair. Conduit replacement was done 12 times in 11 patients, from seven to 31 years after intervention. Twelve patients underwent PVR for pulmonary valve regurgitation with or without PS (Figure 2). Figure 3 shows the event-free curve after PVR.

In summary, the main reasons for re-intervention were ventricular arrhythmia, residual PS including conduit stenosis, and severe pulmonary regurgitation. Ventricular arrhythmia occurred more than 10 years after the initial repair and was often associated with severe pulmonary regurgitation. Residual PS was observed 6 to 22 years after the initial repair. Conduit stenosis occurred at shorter intervals in younger patients. Severe pulmonary regurgitation was often associated with ventricular arrhythmia and in some patients with tricuspid valve regurgitation.

Dr. Masuda concluded that residual in RVOFT and ventricular arrhythmia were the main reasons for re-intervention in patients who had previous repair of TOF or DORV with subaortic VSD and PS. In patients with severe pulmonary regurgitation, early re-intervention should be considered to prevent the development of ventricular arrhythmia.