Pulmonic regurgitation treatment

Pulmonic regurgitation Microchapters
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Aravind Kuchkuntla, M.B.B.S[2], Aysha Anwar, M.B.B.S[3]

Overview

Treatment of pulmonic regurgitation may be divided into medical and surgical treatment. Medical management of pulmonic regurgitation may include use of diuretics in patients with RV dysfunction. ACE inhibitors and B blockers may be used to reverse neurohormonal activation and improve symptoms. Antibiotic prophylaxis may be indicated in certain conditions such as patients with cyanotic heart disease, prosthetic heart valves, rheumatic heart disease, and patients previously having sustained bacterial endocarditis. Surgical management of pulmonic regurgitation may include replacement of pulmonary valve. The major indications for pulmonic valve replacement may include symptomatic patients with arrythmias or NYHA class higher than II, ejection fraction of less than 40% when assessed with CMR, patients with progressive right ventricular regurgitation(right ventricular end- diastolic volume ≥160 mL/m2 or end-systolic volume ≥82 mL/m2 on CMR), moderate to severe tricuspid valve regurgitation, resulting from annular dilation, patients at risk of developing arrythmias and with prolonged QRS duration.(total QRS duration ≥180 msec, or QRS duration increase >3.5 msec per year and severe pulmonic regurgitation in a patient with another cardiac lesion that requires operative intervention. Follow up of patients with pulmonic regurgitation requires regular echocardiographic monitoring after PVR, oral anticoagulation in patients with mechanical or bioprosthetic valves and lifelong follow up to monitor pulmonary valve morphology and RV function.

Treatment

Treatment of pulmonic regurgitation may be divided into medical and surgical treatment:

Medical Therapy

• There are no specific medical measures for management of PR.
• Diuretics are recommended in patients with RV dysfunction for maintenance of fluid balance.
• In patients with repaired tetralogy of fallot, ACE inhibitors or beta-blockers are used to reverse the neuroharmonal activation and improve the symptoms.

Antiobiotic prophylaxis

The American Heart Association Recommendations on Prevention of Bacterial Endocarditis indicate that antibiotic prophylaxis is not necessary for pulmonic regurgitation in those patients with otherwise structurally normal pulmonic valves, particularly if there is no diastolic murmur. It should be noted, though, that those patients with the following conditions may warrant antibiotic prophylaxis:

1. Complex cyanotic heart disease
2. Prosthetic heart valves
3. Patients with congenital heart disease and pulmonic regurgitation
4. Acquired pulmonic valve regurgitation as the result of rheumatic heart disease
5. Patients with complex cyanotic heart disease
6. In patients who have previously sustained bacterial endocarditis

Surgical Therapy

Pulmonary valve replacement (PVR) is one of the most common procedures performed among adults with congenital heart disease, due to different diseases causing regurgitation or stenosis. Patients may undergo reoperations during their lifetime.

Indications for Surgery

Indications for pulmonary valve replacement (PVR) include:

• Symptomatic patients with arrythmias or NYHA class higher than II.
• Ejection fraction of less than 40% when assessed with cardiac MRI. Both right and left ventricular dysfunction serve as an indication.
• Patients with progressive right ventricular dysfunction (right ventricular end-diastolic volume ≥160 mL/m2 or end-systolic volume ≥82 mL/m2 on CMR).
• Moderate to severe tricuspid regurgitation, resulting from annular dilation.
• Patients at risk of developing arrythmias and with prolonged QRS duration.(total QRS duration ≥180 msec, or QRS duration increase >3.5 msec per year).
• Severe PR in a patient with another cardiac lesion (such as RVOT aneurysm) that requires operative intervention.
• According to ACC/AHA guidelines, PVR is reasonable among adults with the previous TOF, severe PR, and any of the following:
  • Moderate to severe RV dysfunction/ enlargement
  • Development of symptomatic or sustained artial and/or ventricular arrhythmias
  • Moderate to severe TR

Timing Of Surgery

• Timing of pulmonary valve replacement is not well defined as in aortic and mitral regurgitation. However timely intervention is advised before the onset of RV dysfunction.
• Pulmonary valve should be replaced before RV end-diastolic volume-index (EDVI) exceeds 163 mL/m2 or RV end-systolic volume index (ESVI) exceeds 80 mL/m2. RV ESVI is the major factor to be considered.
• Delayed intervention has shown to have poor outcomes and higher rate of re-intervention.
• The prime goals of pulmonary valve replacement include improved functional class and quality of life, maintenance of right (and left) ventricular function, risk modification of arrhythmia and sudden cardiac death.

Choice of prosthetic valve

• Bioprosthetic valves:
  • Usually preferred over mechanical valve prosthesis and have a longevity of around 15years.
  • Bioprosthesis utilizes biological tissue that are usually harvested from the [[pericardium}pericardial sac]] of either cows or horses.
  • Do not require anticoagulation.
  • Indications: Informed patient's desire or if there are contraindications/high risk to anticoagulation.
• Mechanical valves:
  • Preferred among patients at high risk of reoperation such as patients with RV dysfunction.
  • Some of the examples include bileaflet (Carbomedics), titing disc (Medtronic-Hall), and the cage.
  • Require long-term anticoagulation.
  • Indications: Age <65-70 years and long life expectancy, informed patient's desire, another heart valve contains a mechanical implant, patient is on anticoagulation already or there are no contraindications to anticoagulation. Patients requiring a redo surgery are high-risk.

Surgical Options

• Pulmonary valve replacement (PVR) by surgical and percutaneous approach is the definitive treatment for the management of chronic PR and has proven to improve RV function, New York Heart Association Functional Class status, quality of life, and reduce risk for development of RV tachyarrhythmias and sudden cardiac death.
• Surgical repair may combine pulmonary valve insertion with correction of the associated defects such as reduction of aneurysmal RVOT or intraoperative cryoablation.
• The indications for both surgical or transcatheter pulmonary valve replacement are similar.
• In the case of free PR with severe discrepancy (>35%) between right and left pulmonary blood flow, patients should undergo balloon dilation, with/without an endoluminal stent implantation.

Surgical Valve Implantation

• Various valved conduits are placed to replace the pulmonic valve which include homografts from cadavers, valved conduits, and the contegra bovine jugular vein graft or a bioprosthetic valve implanted directly in the RV outflow tract.
• Stenosis of the conduit is the major limitation and 25% of patients have to undergo a repeat intervention.

Transcatheter Pulmonary Valve Replacement

• The Melody transcatheter pulmonary valve (Medtronic) was approved by FDA in 2010.
• The current transcatheter valves are designed to treat conduit and bioprosthetic valve failure only.
• For transcatheter valve replacement eligibility, the morphology of RVOT (determined viaCT or MRI) serves as the major criterion. a determination that may easily be made at CT or MRI.
• Contraindications:
  • Patients with an aneurysmal appearance of RVOT do not qualify for transcatheter pulmonary valve implantation.
  • They are not useful to treat patients who had a RVOT reconstruction by transannular patching.

Complications

• Common complications of pulmonary regurgitation (PR) treatment include:
  • Complications post pulmonic valve replacement (PVR) are:
    1. Prosthetic valve failure (PVR or interventional catheter procedure is required to be redone).
    2. Prosthetic valve dysfunction (death due to prosthetic valve dysfunction is very rare).
    3. Atrial fibrillation and atrial flutter are rare complications.
    4. Stent fracture: It leads to an increase in RV outflow tract gradient and RV pressure and its incidence is around 21% in 1 series that used the Melody valve and was the major reason for a repeat intervention.
    5. Device instability and dislodgement
    6. Coronary compression due to stent placement
    7. Pulmonary artery obstruction.
  • Complications post transcatheter pulmonic valve implantation (TPVI) are:
    1. Infective endocarditis is not an uncommon complication. A few patients (such as of streptococcal infection) may be managed medically and surgical or percutaneous reintervention may be required for others.

Outcomes

• Patients with percutaneous pulmonary valve replacement have good outcome and are free of reintervention at 1 year.
• Patients with CMR derived pre operative right ventricular end diastolic volume index of less than 160ml/m² and end systolic volume index of less than 80ml/m² showed better outcomes.

Treatment of arrhythmia

• An invasive electrophysiological study to ablate atrial flutter, and map (if not ablate) ventricular tachycardia is recommended among patients with documented atrial flutter or ventricular tachycardia.
• Before a patient reaches end­stage heart failure, resynchronization therapy is the suggested treatment for dilated right ventricles with the RBBB.
• Among patients with arrhythmias, intraoperative electrophysiological mapping with cryoablation during pulmonary valve replacement has demonstrated promising results. Complete resolution of pre‐existing arrhythmias has been reported.