What is the upper limit of pulmonary artery pressure (PAP) suitable for tricuspid valve repair?

Upper Limit of Pulmonary Artery Pressure for Tricuspid Valve Repair

Tricuspid valve repair is not indicated in asymptomatic patients with tricuspid regurgitation whose pulmonary artery systolic pressure is less than 60 mm Hg in the presence of a normal mitral valve, which suggests 60 mm Hg as the upper threshold for consideration of intervention. 1

Pulmonary Hypertension Classification and Tricuspid Valve Surgery

Pulmonary artery pressure (PAP) is a critical factor in determining candidacy for tricuspid valve repair. The guidelines provide specific recommendations regarding PAP thresholds:

Key PAP Thresholds:

• 60 mm Hg systolic PAP: The ACC/AHA guidelines explicitly state that tricuspid valve repair/replacement is not indicated in asymptomatic patients with tricuspid regurgitation (TR) whose pulmonary artery systolic pressure is less than 60 mm Hg in the presence of a normal mitral valve 1
• 50-55 mm Hg systolic PAP: Systolic pulmonary artery pressures greater than 55 mm Hg are likely to cause TR with anatomically normal tricuspid valves 1
• <40 mm Hg systolic PAP: TR occurring with systolic pulmonary artery pressures less than 40 mm Hg is likely to reflect a structural abnormality of the valve apparatus rather than functional TR 1

Decision Algorithm for Tricuspid Valve Repair Based on PAP

1. PAP <40 mm Hg with TR:

   • Likely indicates primary (structural) tricuspid valve disease
   • Consider repair if severe TR is present and symptomatic 1

2. PAP 40-60 mm Hg with TR:

   • Evaluate for concomitant left-sided heart disease
   • Tricuspid annuloplasty may be considered for less than severe TR in patients undergoing mitral valve surgery when there is pulmonary hypertension or tricuspid annular dilatation 1
   • Repair is reasonable for symptomatic patients with severe primary TR 1

3. PAP >60 mm Hg with TR:

   • Higher surgical risk
   • Consider addressing underlying cause of pulmonary hypertension first
   • Medical therapies to reduce elevated pulmonary artery pressures might be considered before surgical intervention 1

Impact of Pulmonary Hypertension on Outcomes

Recent research indicates that pulmonary hypertension significantly affects outcomes after tricuspid valve intervention:

• Patients with pulmonary vascular resistance (PVR) ≥2.5 Wood units have lower survival rates at 5-year follow-up 2
• Discordance between invasive and echocardiographic measurements of pulmonary hypertension predicts worse outcomes after transcatheter tricuspid valve repair 3
• Pulmonary capillary wedge pressure (PCWP) >16 mmHg is associated with increased mortality and cardiac readmission after transcatheter tricuspid valve repair 4

Assessment of Pulmonary Artery Pressure

Accurate assessment of PAP is essential before considering tricuspid valve repair:

• Echocardiography: Primary non-invasive method for estimating PAP

  • TR jet velocity using modified Bernoulli equation
  • Estimated right atrial pressure based on IVC diameter and collapsibility 5
  • Alternative methods when TR jet is inadequate:
    • Right ventricular outflow tract assessment
    • Right heart chamber evaluation
    • Hepatic vein flow patterns 5

• Right Heart Catheterization: Gold standard for PAP measurement

  • Recommended when clinical and non-invasive data are discordant 1
  • Essential for accurate diagnosis of pulmonary hypertension etiology 1

Clinical Pitfalls and Caveats

1. Underestimation of PAP by echocardiography: Echocardiographic assessment may underestimate true PAP, especially in severe TR. The diagnostic accuracy of echocardiography to detect invasive pulmonary hypertension is only about 55% 3

2. Reversibility assessment: Before excluding patients with high PAP from tricuspid valve repair, assess for reversibility of pulmonary hypertension, especially if due to left-sided heart disease

3. Right ventricular function: Consider RV function in addition to PAP when determining suitability for tricuspid valve repair, as RV adaptation to increased volume and pressure load affects outcomes 6

4. Concomitant procedures: In patients undergoing left-sided valve surgery, consider tricuspid annuloplasty even with less than severe TR if pulmonary hypertension or tricuspid annular dilatation is present 1

In conclusion, while 60 mm Hg systolic PAP represents a significant threshold in the guidelines, the decision for tricuspid valve repair should incorporate assessment of symptoms, TR severity, valve morphology, right ventricular function, and the etiology of pulmonary hypertension.