Louise Coats

Percutaneous Pulmonary Valve Implantation in Humans Results in 59 Consecutive Patients

Background—Right ventricular outflow tract (RVOT) reconstruction with valved conduits in infancy and childhood leads to reintervention for pulmonary regurgitation and stenosis in later life. Methods and Results—Patients with pulmonary regurgitation with or without stenosis after repair of congenital heart disease had percutaneous pulmonary valve implantation (PPVI). Mortality, hemodynamic improvement, freedom from explantation, and subjective and objective changes in exercise tolerance were end points. PPVI was performed successfully in 58 patients, 32 male, with a median age of 16 years and median weight of 56 kg. The majority had a variant of tetralogy of Fallot (n=36), or transposition of the great arteries, ventricular septal defect with pulmonary stenosis (n=8). The right ventricular (RV) pressure (64.4±17.2 to 50.4±14 mm Hg, P<0.001), RVOT gradient (33±24.6 to 19.5±15.3, P<0.001), and pulmonary regurgitation (PR) (grade 2 of greater before, none greater than grade 2 after, P<0.001) decreased significantly after PPVI. MRI showed significant reduction in PR fraction (21±13% versus 3±4%, P<0.001) and in RV end-diastolic volume (EDV) (94±28 versus 82±24 mL · beat−1 · m−2, P<0.001) and a significant increase in left ventricular EDV (64±12 versus 71±13 mL · beat−1 · m−2, P=0.005) and effective RV stroke volume (37±7 versus 42±9 mL · beat−1 · m−2, P=0.006) in 28 patients (age 19±8 years). A further 16 subjects, on metabolic exercise testing, showed significant improvement in &OV0312;o2max (26±7 versus 29±6 mL · kg−1 · min−1, P<0.001). There was no mortality. Conclusions—PPVI is feasible at low risk, with quantifiable improvement in MRI-defined ventricular parameters and pulmonary regurgitation, and results in subjective and objective improvement in exercise capacity.

Percutaneous pulmonary valve implantation impact of evolving technology and learning curve on clinical outcome

Background— Percutaneous pulmonary valve implantation was introduced in the year 2000 as a nonsurgical treatment for patients with right ventricular outflow tract dysfunction. Methods and Results— Between September 2000 and February 2007, 155 patients with stenosis and/or regurgitation underwent percutaneous pulmonary valve implantation. This led to significant reduction in right ventricular systolic pressure (from 63±18 to 45±13 mm Hg, P<0.001) and right ventricular outflow tract gradient (from 37±20 to 17±10 mm Hg, P<0.001). Follow-up ranged from 0 to 83.7 months (median 28.4 months). Freedom from reoperation was 93% (±2%), 86% (±3%), 84% (±4%), and 70% (±13%) at 10, 30, 50, and 70 months, respectively. Freedom from transcatheter reintervention was 95% (±2%), 87% (±3%), 73% (±6%), and 73% (±6%) at 10, 30, 50, and 70 months, respectively. Survival at 83 months was 96.9%. On time-dependent analysis, the first series of 50 patients (log-rank test P<0.001) and patients with a residual gradient >25 mm Hg (log-rank test P=0.01) were associated with a higher risk of reoperations. Conclusions— Percutaneous pulmonary valve implantation resulted in the ability to avoid surgical right ventricular outflow tract revision in the majority of cases. This procedure might reduce the number of operations needed over the total lifetime of patients with right ventricle–to–pulmonary artery conduits.

Biventricular Response After Pulmonary Valve Replacement for Right Ventricular Outflow Tract Dysfunction Is Age a Predictor of Outcome

Background— The timing of pulmonary valve replacement (PVR) for free pulmonary incompetence in patients with congenital heart disease remains a dilemma for clinicians. We wanted to assess the determinants of improvement after PVR for pulmonary regurgitation over a wide range of patient ages and to use any identified predictors to compare clinical outcomes between patient groups. Methods and Results— Seventy-one patients (mean age 22±11 years; range, 8.5 to 64.9; 72% tetralogy of Fallot) underwent PVR for severe pulmonary regurgitation. New York Heart Association class improved after PVR (median of 2 to 1, P<0.0001). MRI and cardiopulmonary exercise testing were performed before and 1 year after intervention. After PVR, there was a significant reduction in right ventricular volumes (end diastolic volume 142±43 to 91±18, end systolic volume 73±33 to 43±14 mL/m2, P<0.0001), whereas left ventricular end diastolic volume increased (66±12 to 73±13 mL/m2, P<0.0001). Effective cardiac output significantly increased (right ventricular: 3.0±0.8 to 3.3±0.8 L/min, P=0.013 and left ventricular: 3.0±0.6 to 3.4±0.7 L/min, P<0.0001). On cardiopulmonary exercise testing, ventilatory response to carbon dioxide production at anaerobic threshold improved from 35.9±5.8 to 34.1±6.2 (P=0.008). Normalization of ventilatory response to carbon dioxide production was most likely to occur when PVR was performed at an age younger than 17.5 years (P=0.013). Conclusions— A relatively aggressive PVR policy (end diastolic volume <150 mL/m2) leads to normalization of right ventricular volumes, improvement in biventricular function, and submaximal exercise capacity. Normalization of ventilatory response to carbon dioxide production is most likely to occur when surgery is performed at an age ≤17.5 years. This is also associated with a better left ventricular filling and systolic function after surgery.

Risk Stratification, Systematic Classification, and Anticipatory Management Strategies for Stent Fracture After Percutaneous Pulmonary Valve Implantation

Background— We analyzed the incidence, risk factors and treatment options for stent fracture after percutaneous pulmonary valve (PPV) implantation (PPVI). Methods and Results— After PPVI, 123 patients had chest x-ray in anteroposterior and lateral projection, echocardiography, and clinical evaluation during structured follow-up. Of these 123 patients, 26 (21.1%) developed stent fracture 0 to 843 days after PPVI (stent fracture–free survival at 1 year, 85.1%; at 2 years, 74.5%; and at 3 years, 69.2%). Stent fracture was classified as type I: no loss of stent integrity (n=17); type II: loss of integrity with restenosis on echocardiography (n=8); and type III: separation of fragments or embolization (n=1). In a multivariate Cox regression, we analyzed various factors, of which 3 were associated with a higher risk of stent fracture: implantation into “native” right ventricular outflow tract (P=0.04), no calcification along the right ventricular outflow tract (judged with fluoroscopy, P=0.02), recoil of PPV (qualitatively, PPV diameter in frontal or lateral plane with fully inflated balloon > diameter after balloon deflation, P=0.03). Substernal PPV location, high-pressure post-PPVI dilatation of PPV, pre-PPVI right ventricular outflow tract gradients, and other indicators of PPV compression or asymmetry did not pose increased risk. Patients with type I fracture remain under follow-up. Patients with type II fracture had 2nd PPVI or are awaiting such procedure, and 1 patient with type III fracture required surgical explantation. Conclusion— Stent fracture after PPVI can be managed effectively by risk stratification, systematic classification, and anticipatory management strategies. Serial x-ray and echocardiography are recommended for surveillance.

Physiological and Clinical Consequences of Relief of Right Ventricular Outflow Tract Obstruction Late After Repair of Congenital Heart Defects

Background— Right ventricular outflow tract obstruction (RVOTO) is a common problem after repair of congenital heart disease. Percutaneous pulmonary valve implantation (PPVI) can treat this condition without consequent pulmonary regurgitation or cardiopulmonary bypass. Our aim was to investigate the clinical and physiological response to relieving RVOTO. Methods and Results— We studied 18 patients who underwent PPVI for RVOTO (72% male, median age 20 years) from a total of 93 who had this procedure for various indications. All had a right ventricular outflow tract (RVOT) gradient >50 mm Hg on echocardiography without important pulmonary regurgitation (less than mild or regurgitant fraction <10% on magnetic resonance imaging [MRI]). Cardiopulmonary exercise testing, tissue Doppler echocardiography, and MRI were performed before and within 50 days of PPVI. PPVI reduced RVOT gradient (51.4 to 21.7 mm Hg, P<0.001) and right ventricular systolic pressure (72.8 to 47.3 mm Hg, P<0.001) at catheterization. Symptoms and aerobic (25.7 to 28.9 mL · kg−1 · min−1, P=0.002) and anaerobic (14.4 to 16.2 mL · kg−1 · min−1, P=0.002) exercise capacity improved. Myocardial systolic velocity improved acutely (tricuspid 4.8 to 5.3 cm/s, P=0.05; mitral 4.7 to 5.5 cm/s, P=0.01), whereas isovolumic acceleration was unchanged. The tricuspid annular velocity was not maintained on intermediate follow-up. Right ventricular end-diastolic volume (99.9 to 89.7 mL/m2, P<0.001) fell, whereas effective stroke volume (43.7 to 48.3 mL/m2, P=0.06) and ejection fraction (48.0% to 56.8%, P=0.01) increased. Left ventricular end-diastolic volume (72.5 to 77.4 mL/m2, P=0.145), stroke volume (45.3 to 50.6 mL/m2, P=0.02), and ejection fraction (62.6% to 65.8%, P=0.03) increased. Conclusions— PPVI relieves RVOTO, which leads to an early improvement in biventricular performance. Furthermore, it reduces symptoms and improves exercise tolerance. These findings have important implications for the management of this increasingly common condition.

Variations in right ventricular outflow tract morphology following repair of congenital heart disease: Implications for percutaneous pulmonary valve implantation

OBJECTIVE Our aim was to identify sub-groups of right ventricular outflow tract morphology that would be suitable for percutaneous pulmonary valve implantation and to document their prevalence in our patient population. MATERIALS AND METHODS Eighty-three consecutive patients with right ventricular outflow tract dysfunction (5-41 years, 76% tetralogy of Fallot) referred to our center for cardiovascular magnetic resonance were studied. A morphological classification was created according to visual assessment of three-dimensional reconstructions and detailed measurement. Diagnosis, right ventricular outflow tract type, surgical history and treatment outcomes were documented. RESULTS Right ventricular outflow tract morphology was heterogeneous; nevertheless, 5 patterns were visually identified. Type I, a pyramidal morphology, was most prevalent (49%) and related to the presence of a transannular patch. Other types (II-V) were seen more commonly in patients with conduits. Two patients had unclassifiable morphology. Ninety-five percent of patients were assigned to the correct morphological classification by visual assessment alone. Percutaneous pulmonary valve implantation was performed successfully in 10 patients with Type II-V morphology and in 1 patient with unclassifiable morphology. Percutaneous implantation was not performed in patients with Type I morphology. Only right ventricular outflow tract diameters < 22 mm in diameter were suitable for the current device. CONCLUSIONS We have created a morphological classification of the RVOT in patients referred for assessment of RVOT dysfunction. Though only 13% of our patients underwent percutaneous implantation, > 50% of outflow tract morphologies may be suitable for this approach, in particular with the development of new devices appropriate for larger outflow.

Images in cardiovascular medicine. Transcatheter right ventricular outflow tract intervention: the risk to the coronary circulation.

A14-year-old male with degeneration of his right ventricular to pulmonary artery homograft conduit was referred to us for percutaneous pulmonary valve implantation (PPVI).1 Magnetic resonance imaging indicated close proximity of the left anterior descending coronary artery to the homograft (Figure, A). To test whether PPVI would compress the coronary artery, an 18-mm Mullins balloon (NuMed Inc, Hopkinton, NY) was inflated within the homograft, bringing it to its maximum diameter and mimicking stent implantation. Simultaneous selective coronary angiography demonstrated significant compression of the left anterior descending coronary artery (Figure, B). The balloon was deflated, after which normal coronary flow was restored (Figure, C), and thus PPVI was not performed. The patient was referred for surgery. Sources of Funding Dr Coats has received a British Heart Foundation Junior Fellowship Grant. Dr Taylor’s work is funded by an HEFCE grant. Dr Bonhoeffer has received a British Heart Foundation Programme Grant.A 14-year-old male with degeneration of his right ventricular to pulmonary artery homograft conduit was referred to us for percutaneous pulmonary valve implantation (PPVI).1 Magnetic resonance imaging indicated close proximity of the left anterior descending coronary artery to the homograft (Figure, A). To test whether PPVI would compress the …

Effective transcatheter valve implantation after pulmonary homograft failure: A new perspective on the Ross operation

OBJECTIVE The Ross procedure offers good autograft function and low reoperation rates for the neoaortic valve; however, the rate of conduit dysfunction in the right ventricular outflow tract remains a concern. This study assessed percutaneous pulmonary valve implantation in this setting. METHODS We retrospectively analyzed outcomes of 12 patients (mean age 28 +/- 5 years) referred for percutaneous pulmonary valve implantation to treat right ventricle-pulmonary artery conduit failure 11.1 +/- 3.3 years after Ross procedure. RESULTS Percutaneous pulmonary valve implantation was feasible in all 12 patients, with no procedural complications (procedure time 99 +/- 16 minutes, fluoroscopy time 21 +/- 6 minutes). Right ventricular outflow tract gradient during catheterization and pulmonary regurgitant fraction on magnetic resonance imaging fell after valve implantation (gradient 34 +/- 6 to 14 +/- 3 mm Hg, P < .01, regurgitant fraction 20% +/- 6% to 2% +/- 1%, P < .05). After restoration of right ventricular outflow tract function, indexed right ventricular end-diastolic volume decreased (91 +/- 13 to 78 +/- 12 mL x beat(-1) x m(-2), P < .01) and maximal cardiopulmonary exercise performance improved (peak oxygen consumption 25.4 +/- 2.3 to 30.8 +/- 3.0 mL x kg(-1) x min(-1), P < .01). During follow-up (18.8 +/- 4.6 months), there was 1 device explantation (restenosis). The probabilities of freedom from right ventricular outflow tract reoperation were 100% at 1 year and 90% at 3 years. CONCLUSIONS Percutaneous pulmonary valve implantation provides an effective transcatheter treatment strategy to prolong the lifespan of right ventricle-pulmonary artery conduits after the Ross procedure, reducing the reoperation burden on patients with aortic valve disease.

The single-ventricle patient population: a current and future concern a population-based study in the North of England

Objective To estimate the size and characteristics of the UK population with single-ventricle physiology, and predict future population growth. Methods The surviving population with single-ventricle physiology in Northern England (resident population 2.9 million) was identified from our clinical database and the Northern Congenital Abnormality Survey (NorCAS). Conditions included double inlet ventricle, tricuspid atresia, mitral atresia, hypoplastic left heart syndrome and other unbalanced defects. Fetal diagnoses, terminations of pregnancy and surgical interventions were reviewed. Childhood and adult prevalence of single-ventricle physiology were calculated. Current and future National population figures were estimated using expected mortality derived from literature. Results 80 children and 48 adults with single-ventricle physiology were identified in the NorCAS region. The most frequent underlying condition in childhood was hypoplastic left heart, and among adults was double inlet ventricle. All children over 5 years of age had completed a Fontan repair (89%) or had a Glenn anastomosis. Seven adults had not undergone a Glenn shunt or Fontan procedure. Of those patients over 30 years of age (n=12), 50% were New York Heart Association (NYHA) functional class 3, compared to 3% of those under 30 years (p=0.001). Regional childhood and adult prevalence of single-ventricle physiology was 16 and 2 per 100 000, respectively. Conclusions The current UK single-ventricle population is composed of around 1040 adults and 1700 children. Adult numbers will increase by over 60% in the next decade with the proportion in NHYA functional class 3 set to double.

Immediate clinical and haemodynamic benefits of restoration of pulmonary valvar competence in patients with pulmonary hypertension

Objective: To analyse the potential benefit of restoration of pulmonary valvar competence in patients with severe pulmonary regurgitation (PR) and pulmonary hypertension (PH) associated with congenital heart disease. Design: Retrospective study. Setting: Tertiary paediatric and adult congenital heart cardiac centre. Interventions: Percutaneous pulmonary valve implantation (PPVI). Patients: All patients who underwent PPVI for treatment of PR in the presence of PH (mean PAP >25 mm Hg). Results: Seven patients with severe PH as a result of congenital heart disease and severe PR underwent PPVI. The valve implantation procedure was feasible and uncomplicated in all seven cases, successfully abolishing PR. There was a significant increase in diastolic (15.4 (7.3) to 34.0 (8.5) mm Hg; p = 0.007) and mean (29.7 (8.1) to 41.3 (12.9) mm Hg; p = 0.034) pulmonary artery pressures, and an improvement in NYHA functional class (from median IV to median III; p<0.008). Peripheral oxygen saturations rose from 85.9% (11.0%) to 91.7% (8.3%) (p = 0.036). Right ventricular (RV) volumes decreased (from 157.0 (44.7) to 140.3 (53.3) ml/m2), while effective RV stroke volume increased (from 23.4 (9.3) to 41.0 (11.6) ml/m2). During a median follow-up of 20.3 months (range 1.3–47.5), valvar competence was well maintained despite near systemic pulmonary pressures. None of the valved stents were explanted during follow-up. Conclusion: Trans-catheter treatment of PR in patients with PH is well tolerated and leads to clinical and haemodynamic improvement, most probably caused by a combination of increased pulmonary perfusion pressures and RV efficiency.