Pulmonary Valve Stenosis: From Diagnosis to Current Management Techniques and Future Prospects

Pulmonary stenosis (PS) is mainly a congenital defect that accounts for 7-12% of congenital heart diseases (CHD). It can be isolated or, more frequently, associated with other congenital defects (25-30%) involving anomalies of the pulmonary vascular tree. For the diagnosis of PS an integrated approach with echocardiography, cardiac computed tomography and cardiac magnetic resonance (CMR) is of paramount importance for the planning of the interventional treatment. In recent years, transcatheter approaches for the treatment of PS have increased however, meaning surgery is a possible option for complicated cases with anatomy not suitable for percutaneous treatment. The present review aims to summarize current knowledge regarding diagnosis and treatment of PS.

Pulmonary valve replacement following repair of tetralogy of Fallot: comparison of outcomes between bio- and mechanical prostheses

OBJECTIVES

The aims of this study were to evaluate and compare the outcomes after pulmonary valve replacement (PVR) with a mechanical prosthesis (MP) and a bioprosthesis (BP).

METHODS

From 2004 through 2017, a total of 131 patients, who had already been repaired for tetralogy or Fallot or its variants, underwent their first PVR with an MP or a BP. Outcomes of interests were prosthesis failure (stenosis >3.5 m/s, regurgitation >mild or infective endocarditis) and reintervention.

RESULTS

The median age at PVR was 19 years. BP and MP were used in 88 (67.2%) and 43 (32.8%) patients, respectively. The median follow-up duration was 7.4 years, and the 10-year survival rate was 96.4%. Risk factors for prosthesis failure were smaller body surface area [hazard ratio (HR) 0.23 per 1 m2, P = 0.047] and smaller prosthesis size (HR 0.73 per 1 mm, P = 0.039). Risk factors for prosthesis reintervention were smaller body surface area (HR 0.11 per 1 m2, P = 0.011) and prosthesis size (HR 0.67 per 1 mm, P = 0.044). Probability of prosthesis failure and reintervention at 10 years were 24.6% (19.5% in BP vs 34.8% in MP, P = 0.34) and 7.8% (5.6% in BP vs 11.9% in MP, P = 0.079), respectively. Anticoagulation-related major thromboembolic events were observed in 4 patients receiving an MP.

CONCLUSIONS

MP might not be superior to BP in terms of prosthesis failure or reintervention. MP should be carefully considered for highly selected patients in the era of transcatheter PVR.

Assessment of normal hemodynamic profile of mechanical pulmonary prosthesis by doppler echocardiography: a prospective cross-sectional study

Objectives

Very few reports have described the Doppler-derived echocardiographic parameters for mechanical pulmonary valve prosthesis (MPVP). This study aims to describe the normal Doppler hemodynamic profile of MPVP using Doppler echocardiography.

Methods

The current prospective, single center observational study enrolled 108 patients who underwent pulmonary valve replacement (PVR) surgery for the first time and had a normally functioning prosthesis post-operation. The hemodynamic performance of MPVPs, considering flow dependent and flow independent parameters, was evaluated at two follow-up points, at week one and week four post-operation. All assessments were conducted by an experienced echocardiographer.

Results

The mean age (±SD) of the participants was 26.4 (±8.98). Tetralogy of Fallot (ToF) was the most common underlying disease leading to PVR, with a prevalence of 88%. At first week post-operation, measurement of indices reported the following values (±SD): peak pressure gradient (PPG): 18.51(±7.64) mm Hg; mean pressure gradient (MPG): 10.88(±5.62) mm Hg; peak velocity (PV): 1.97(±0.43)m/s; doppler velocity index (DVI): 0.61(±18); pulmonary velocity acceleration time (PVAT): 87.35(±15.16) ms; effective orifice area (EOA): 2.98(±1.02) cm²;and effective orifice area to body surface area ratio (EOA/ BSA): 1.81(±0.62) cm²/m². Comparing these measurements with those obtained from the second follow-up (at week four post-op) failed to hold significant difference in all values except for PVAT, which had increased from its primary value (p = 0.038). Also, right ventricular (RV) function showed significant improvement throughout the follow up period.

Conclusion

The findings of this study help strengthen the previously scarce data pool and better establish the normal values for Doppler hemodynamics in mechanical pulmonary prosthesis.

Porcine Versus Pericardial Pulmonary Valve Replacement in Adults With Prior Congenital Cardiac Surgery: Midterm Outcomes

Background:

Postcongenital heart surgery pulmonary regurgitation requires subsequent pulmonary valve replacement. We sought to compare the outcomes of pulmonary valve replacement after using bioprosthetic valves, porcine versus pericardial bioprosthesis.

Method:

Retrospective single-center study of consecutive pulmonary valve replacement in patients with pulmonary regurgitation following initial congenital cardiac surgery. From 2004 to 2016, 82 adult patients (53 males, 29 females) underwent pulmonary valve replacement at a mean age of 28.7 ± 8 years (range 18-52 years) with a mean time to pulmonary valve replacement of 24 ± 7 years (range 13-43 years). Porcine bioprosthetic valves (group 1, n = 32) and pericardial valves (group 2, n = 50) were used. Cardiac magnetic resonance imaging was performed (n = 54) at a mean of 18 ± 13 months before and 24 ± 21 months after pulmonary valve replacement.

Results:

No significant difference was seen between the groups except that the mean follow-up was longer for group 1 (5.02 ± 2.06 vs 4.08 ± 3.21 years). In-hospital mortality was 1.1%. Follow-up completeness was 100% with no late death. Mean right ventricular end-systolic and end-diastolic volumes reduced significantly in both the groups ( P < .001), whereas right ventricular ejection fraction remained unchanged (group 1, P = .129; group 2, P = .675) . Only the left ventricular end-diastolic volume increased in both the groups, but the increase was significant for group 2 only (group 1, P = .070; group 2, P = .015), whereas the left ventricular end-systolic and ejection fraction remained unchanged in both the groups. There was no reoperation for pulmonary valve replacement. Freedom from intervention was 93.8% (group 1) and 100% (group 2) at eight years after pulmonary valve replacement ( P = .407).

Conclusion:

Midterm outcomes of pulmonary valve replacement in our adult cohort were satisfactory. Both types of bioprosthetic valves performed comparably for eight years and were a good option in adults.

Mid-term outcomes of mechanical pulmonary valve replacement: a single-institutional experience of 396 patients

OBJECTIVES

Previous small-sized studies have demonstrated the safety and efficacy of mechanical pulmonary valve replacement (mPVR) in patients with congenital heart disease; however, the predictors of major complications and reoperation remained unclear.

METHODS

In a retrospective study, we reported the mid-term outcomes of a large-scaled series of patients, 396 patients, with congenital heart diseases who underwent mPVR in a single institution.

RESULTS

The patients' mean age at mPVR was 24.3 ± 9 years (4-58 years). Most patients (84.3%) underwent tetralogy of Fallot total correction. The median of follow-up was 36 months (24-49 months). Prosthetic valve malfunction caused by thrombosis or pannus formation developed in 12.1% of patients during follow-up period. Reoperation was performed in 7 cases with pannus formation and 6 cases with mechanical valve thrombosis. Freedom from reoperation at 1, 5, and 10 years was 99%, 97%, and 96%, respectively. Neither early nor mid-term mortalities were detected. Cox regression models showed that male gender and smaller valve size increased the risk of prosthetic valve failure. The age at mPVR, interval between congenital heart defect repair and mPVR, and concomitant procedures predicted reoperation. In multivariate analysis, younger age and the interval between first operation and mPVR predicted reoperation either.

CONCLUSIONS

The success rate of mPVR is excellent in mid-term follow-up. Younger age, longer interval between the repair of congenital defect and mPVR, and cooperation increased reoperation risk. However, strict adherence to life-long anticoagulation regimen and patient selection are of great importance for the implementation of mPVR.

Pulmonary Valve Regurgitation: Neither Interventional Nor Surgery Fits All

Introduction: PV implantation is indicated for severe PV regurgitation after surgery for congenital heart defects, but debates accompany the following issues: timing of PV implantation; choice of the approach, percutaneous interventional vs. surgical PV implantation, and choice of the most suitable valve. Timing of pulmonary valve implantation: The presence of symptoms is class I evidence indication for PV implantation. In asymptomatic patients indication is agreed for any of the following criteria: PV regurgitation > 20%, indexed end-diastolic right ventricular volume > 120-150 ml/m2 BSA, and indexed end-systolic right ventricular volume > 80-90 ml/m2 BSA. Choice of the approach: percutaneous interventional vs. surgical: The choice of the approach depends upon the morphology and the size of the right ventricular outflow tract, the morphology and the size of the pulmonary arteries, the presence of residual intra-cardiac defects and the presence of extremely dilated right ventricle. Choice of the most suitable valve for surgical implantation: Biological valves are first choice in most of the reported studies. A relatively large size of the biological prosthesis presents the advantage of avoiding a right ventricular outflow tract obstruction, and also of allowing for future percutaneous valve-in-valve implantation. Alternatively, biological valved conduits can be implanted between the right ventricle and pulmonary artery, particularly when a reconstruction of the main pulmonary artery and/or its branches is required. Hybrid options: combination of interventional and surgical: Many progresses extended the implantation of a PV with combined hybrid interventional and surgical approaches. Major efforts have been made to overcome the current limits of percutaneous PV implantation, namely the excessive size of a dilated right ventricular outflow tract and the absence of a cylindrical geometry of the right ventricular outflow tract as a suitable landing for a percutaneous PV implantation. Conclusion: Despite tremendous progress obtained with modern technologies, and the endless fantasy of researchers trying to explore new forms of treatment, it is too early to say that either the interventional or the surgical approach to implant a PV can fit all patients with good long-term results.

Trifecta St. Jude medical® aortic valve in pulmonary position

Introduction: To evaluate an aortic pericardial valve for pulmonary valve (PV) regurgitation after repair of congenital heart defects.

Methods: From July 2012 to June 2016 71 patients, mean age 24 ± 13 years (four to years) underwent PV implantation of aortic pericardial valve, mean interval after previous repair = 21 ± 10 years (two to 47 years). Previous surgery at mean age 3.2 ± 7.2 years (one day to 49 years): tetralogy of Fallot repair in 83% (59/71), pulmonary valvotomy in 11% (8/71), relief of right ventricular outflow tract (RVOT) obstruction in 6% (4/71). Pre-operative echocardiography and MRI showed severe PV regurgitation in 97% (69/71), moderate in 3% (2/71) with associated RVOT obstruction. MRI and knowledge-based reconstruction 3D volumetry (KBR-3D-volumetry) showed mean PV regurgitation = 42 ± 9% (20–58%), mean indexed RV end-diastolic volume = 169 ± 33 (130–265) ml m^–2 BSA and mean ejection fraction (EF) = 46 ± 8% (33–61%). Cardio-pulmonary exercise showed mean peak O₂/uptake = 24 ± 8 ml kg^–1 min^–1 (14–45 ml kg^–1 min^–1), predicted max O₂/uptake 66 ± 17% (26–97%). Pre-operative NYHA class was I in 17% (12/71) patients, II in 70% (50/71) and III in 13% (9/71).

Results: Mean cardio-pulmonary bypass duration was 95 ± 30ʹ (38–190ʹ), mean aortic cross-clamp in 23% (16/71) 46 ± 31ʹ (8–95ʹ), with 77% (55/71) implantations without aortic cross-clamp. Size of implanted PV: 21 mm in seven patients, 23 mm in 33, 25 mm in 23, and 27 mm in eight. The z-score of the implanted PV was −0.16 ± 0.80 (−1.6 to 2.5), effective orifice area indexed (for BSA) of native PV was 1.5 ± 0.2 (1.2 to –2.1) vs. implanted PV 1.2 ± 0.3 (0.76 to –2.5) (p = ns). In 76% (54/71) patients surgical RV modelling was associated. Mean duration of mechanical ventilation was 6 ± 5 h (0–26 h), mean ICU stay 21 ± 11 h (12–64 h), mean hospital stay 6 ± 3 days (three to 19 days). In mean follow-up = 25 ± 14 months (six to 53 months) there were no early/late deaths, no need for cardiac intervention/re-operation, no valve-related complications, thrombosis or endocarditis. Last echocardiography showed absent PV regurgitation in 87.3% (62/71) patients, trivial/mild degree in 11.3% (8/71), moderate degree in 1.45% (1/71), mean max peak velocity through RVOT 1.6 ± 0.4 (1.0–2.4) m s^–1. Mean indexed RV end-diastolic volume at MRI/KBR-3D-volumetry was 96 ± 20 (63–151) ml m^–2 BSA, lower than pre-operatively (p < 0.001), and mean EF = 55 ± 4% (49–61%), higher than pre-operatively (p < 0.05). Almost all patients (99% = 70/71) remain in NYHA class I, 1.45% = 1/71 in class II.

Conclusion: (a) Aortic pericardial valve is implantable in PV position with an easy and reproducible surgical technique; (b) valve size adequate for patient BSA can be implanted with simultaneous RV remodelling; (c) medium-term outcomes are good with maintained PV function, RV dimensions significantly reduced and EF significantly improved; (d) adequate valve size will allow later percutaneous valve-in-valve implantation.