What is the role of right heart catheterization (RHC) in diagnosing and managing patients with suspected pulmonary hypertension or heart failure, considering their age, medical history, and previous cardiovascular conditions?

Right Heart Catheterization in Pulmonary Hypertension and Heart Failure

Direct Answer

Right heart catheterization is mandatory to confirm the diagnosis of pulmonary hypertension, establish disease severity, and guide all treatment decisions before initiating any PAH-specific therapies. 1, 2

Primary Diagnostic Indications

Pulmonary Hypertension Diagnosis

• RHC is required to confirm PH diagnosis in all suspected cases - echocardiography alone is insufficient and should never be relied upon to diagnose PAH before starting treatment. 1, 2
• RHC must demonstrate mean pulmonary artery pressure >20 mmHg to confirm PH, with additional criteria for PAH including pulmonary artery wedge pressure ≤15 mmHg and pulmonary vascular resistance ≥3 Wood units. 2
• The procedure provides the "gold standard" for pulmonary hemodynamic measurement and is necessary to exclude other etiologies such as intracardiac shunts, extracardiac shunts, and left heart disease. 1

Heart Failure Assessment

• RHC is indicated when patients have persistent symptoms despite empiric therapy AND clinical assessment cannot determine whether the problem is inadequate fluid status, poor perfusion, or elevated vascular resistance. 2
• Perform RHC when renal function worsens with diuretic therapy and it remains unclear if this reflects inadequate perfusion versus overdiuresis. 2
• RHC is mandatory in presumed cardiogenic shock requiring escalating pressor therapy, particularly when considering mechanical circulatory support devices. 2
• Use RHC when patients appear dependent on intravenous inotropes after initial improvement to determine if ongoing hemodynamic support is truly necessary. 2

Specific Clinical Scenarios

• RHC is mandatory before organ transplantation decisions in patients with PH due to left heart disease (Group 2) or lung disease (Group 3). 2
• In chronic thromboembolic pulmonary hypertension (CTEPH), RHC is required to confirm diagnosis and guide treatment decisions, including surgical candidacy. 2
• For congenital cardiac shunts with PH, RHC is necessary to assess pulmonary vascular resistance and shunt hemodynamics to support decisions regarding surgical correction. 2

Critical Procedural Requirements

Where to Perform RHC

• All RHC procedures in pulmonary hypertension patients must be performed at expert centers due to technical complexity and potential for serious complications. 2
• RHC should never be performed outside expert centers for PH evaluation, as inexperienced operators face significantly higher complication rates. 2

Vascular Access

• The right internal jugular vein is the preferred approach, used in 89.1% of procedures in high-volume centers. 3
• RHC via the internal jugular vein is quick (median 15 minutes), safe, and well tolerated when performed by experienced operators. 4

Safety Profile

• Overall complication rates are low at 1.7-3.9% in contemporary practice. 3, 4
• Minor complications include local hematoma (2.2%), incidental artery puncture (1.1%), and atrial arrhythmia (0.2%). 3
• Major complications are rare and include carotid artery injury, pneumothorax (0.2%), and pulmonary edema (0.2%). 3
• RHC can be safely performed in patients ≥70 years of age without increased major complication rates. 5

Hemodynamic Data Obtained and Clinical Utility

Measurements Provided

• RHC provides direct measurements of right atrial pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, pulmonary blood flow, mixed venous oxygen saturation, and calculated pulmonary vascular resistance. 1
• These hemodynamic parameters were found to be predictive of survival in the NIH Registry, with mean PAP, mean RAP, and cardiac index forming the basis of survival prediction formulas. 1

Limitations to Acknowledge

• Measurements are obtained only under resting conditions in the supine position, which may not represent hemodynamic responses to upright posture, activity, or sleep. 1
• Spontaneous variability in pulmonary arterial pressure can be ±20 mmHg even without intervention, with a mean coefficient of variability of 8%. 1, 2

Vasoreactivity Testing

When to Perform

• Vasoreactivity testing is indicated ONLY in expert centers and ONLY for patients with idiopathic PAH, heritable PAH, or drug-induced PAH to identify candidates for high-dose calcium channel blocker therapy. 2, 6
• Vasoreactivity testing should NOT be performed in other PAH subtypes including congenital heart disease-associated PAH, or in PH groups 2,3,4, and 5. 6

Testing Protocol

• Nitric oxide is the recommended agent for performing vasoreactivity testing. 2
• A positive response is defined as a reduction of mean PAP ≥10 mmHg to reach an absolute value ≤40 mmHg with increased or unchanged cardiac output. 2
• Approximately 46.9% of tested patients demonstrate acute vasoreactivity, though only ~10% of IPAH patients ultimately qualify for calcium channel blocker monotherapy. 6, 3

Common Pitfalls to Avoid

• Never initiate PAH-specific therapies based on echocardiography alone - RHC confirmation is mandatory. 2
• Do not perform ambulatory catheterization in patients with NYHA class III-IV heart failure, severe pulmonary hypertension, or suspected active endocarditis. 2
• Avoid performing vasoreactivity testing in CHD-associated PAH patients, as it provides no clinically useful information and exposes patients to unnecessary procedural risks. 6
• Do not rely on RHC measurements as static values - recognize the inherent variability and consider clinical context. 1, 2