Why is right heart catheterization (RHC) performed in patients with heart failure?

Right Heart Catheterization in Heart Failure

Right heart catheterization (RHC) in heart failure is reserved for specific clinical scenarios where hemodynamic data will directly change management decisions—it is NOT a routine diagnostic test. 1

Primary Indications for RHC in Heart Failure

Acute Decompensated Heart Failure with Diagnostic Uncertainty

RHC is indicated when patients have persistent symptoms despite empiric therapy AND clinical assessment cannot determine the underlying hemodynamic problem. 1 Specifically, perform RHC when:

• Fluid status, perfusion, or vascular resistance remains uncertain despite standard clinical evaluation 1
• Systolic pressure remains low or symptomatic despite initial therapy 1
• Renal function worsens with diuretic therapy, and you cannot determine if this reflects inadequate perfusion versus overdiuresis 1
• Patients require escalating parenteral vasoactive agents (inotropes or vasopressors) 1

Cardiogenic Shock

RHC is mandatory in presumed cardiogenic shock requiring escalating pressor therapy, particularly when considering mechanical circulatory support (MCS) devices 1. The hemodynamic data obtained—cardiac output, filling pressures, and vascular resistance—directly guide selection and timing of MCS 2, 3.

Pre-Transplant and MCS Evaluation

RHC is required when evaluating patients for heart transplantation or MCS implantation to assess:

• Pulmonary vascular resistance (PVR), which determines transplant candidacy 2, 4
• Fixed versus reversible pulmonary hypertension through vasoreactivity testing 5
• Right ventricular function and filling pressures 2

Elevated PVR (>3 Wood units) may preclude transplantation unless reversible with vasodilators 5.

Suspected Pulmonary Hypertension Complicating Heart Failure

When heart failure patients have suspected pulmonary hypertension (Group 2 PH), RHC is mandatory to confirm diagnosis and distinguish pre-capillary from post-capillary PH before initiating any PAH-specific therapies 1, 5. The distinction is critical because:

• Post-capillary PH (pulmonary artery wedge pressure >15 mmHg) requires optimization of left heart failure management 5, 4
• Combined pre- and post-capillary PH (PAWP >15 mmHg AND PVR ≥3 Wood units) may require specialized therapies 5
• Echocardiography alone cannot reliably diagnose or exclude pulmonary hypertension—RHC confirmation is mandatory 5

Persistent Dependence on Inotropic Support

RHC is indicated when patients appear dependent on intravenous inotropes after initial clinical improvement, to determine if ongoing hemodynamic support is truly necessary or if weaning can proceed 1.

When RHC is NOT Indicated

Routine invasive hemodynamic monitoring is explicitly NOT recommended in normotensive patients with acute heart failure who respond symptomatically to diuretics and vasodilators 1. This represents the majority of acute heart failure admissions.

RHC should not be performed routinely or periodically in stable chronic heart failure patients, as most heart failure medications are dosed based on clinical trials rather than hemodynamic targets 1.

Critical Procedural Considerations

Expertise Requirements

All RHC procedures in patients with pulmonary hypertension must be performed at expert centers due to technical complexity and potential for serious complications 5. The accuracy of measurements depends heavily on operator experience 1, 4.

Measurement Limitations

Be aware that RHC has inherent limitations 1:

• Measurements reflect only resting, supine conditions, not responses to activity or upright posture 1
• Spontaneous variability in pulmonary artery pressure can be ±20 mmHg even without intervention 1
• Accurate wedge pressure measurement can be technically challenging and requires proper catheter positioning 6

Fluid Challenge Testing

When resting wedge pressure is borderline (12-15 mmHg) and heart failure diagnosis remains uncertain, a fluid challenge test can unmask occult left heart failure 6. Infuse 500 mL or 7 mL/kg saline; a wedge pressure ≥18 mmHg post-infusion suggests diastolic dysfunction 6.

Key Hemodynamic Definitions

Understanding these thresholds is essential for interpretation 5:

• Pulmonary hypertension: Mean PA pressure >20 mmHg (recently lowered from >25 mmHg)
• Pulmonary arterial hypertension: Mean PA pressure >20 mmHg AND wedge pressure ≤15 mmHg AND PVR ≥3 Wood units
• Post-capillary PH (from left heart disease): Mean PA pressure >20 mmHg AND wedge pressure >15 mmHg

Common Pitfalls to Avoid

Never perform RHC "just to see" what the numbers are—the procedure should only be done when results will change management 1, 7. The ESCAPE trial showed no benefit from routine PA catheter use in hospitalized heart failure patients, likely because hemodynamic data were obtained in patients who didn't need it 7.

Do not rely on echocardiography alone to diagnose pulmonary hypertension before starting PAH-specific therapies—the false-positive rate is unacceptably high 5. Tricuspid regurgitation velocity ≥2.5 m/s has poor positive predictive value for true PAH 1.

Avoid ambulatory RHC in high-risk patients: those with NYHA class III-IV symptoms, severe pulmonary hypertension, or suspected active endocarditis require inpatient monitoring 8, 9.