Who should a patient with mild pulmonary hypertension be referred to for further evaluation and management?

Referral of Patients with Mild Pulmonary Hypertension

Patients with mild pulmonary hypertension should be referred to a specialized pulmonary hypertension (PH) center if they have clinical or echocardiographic signs of severe PH and/or severe right ventricular (RV) dysfunction, or when symptoms are disproportionate to the severity of any underlying lung or heart disease. 1

Key Indications for Specialist Referral

Immediate Referral Criteria

The following patients require prompt referral to a PH expert center:

• Patients with severe PH and/or severe RV dysfunction on echocardiography, regardless of the "mild" clinical designation 1
• Patients with mild underlying lung disease but severe PH, where it's unclear whether PH is due to the lung disease or represents concurrent pulmonary arterial hypertension (PAH) 1
• Patients with PH due to left heart disease (PH-LHD) who have a severe pre-capillary component indicated by high diastolic pressure gradient (DPG) and/or high pulmonary vascular resistance (PVR) 1
• Patients with suspected PAH or chronic thromboembolic pulmonary hypertension (CTEPH) after excluding left heart disease and lung disease 1, 2

Clinical Red Flags Requiring Specialist Evaluation

Symptoms disproportionate to underlying disease severity warrant further evaluation and potential referral 1:

• Exertional dyspnea more severe than expected based on pulmonary function test results
• Episodes of syncope (especially with exertion)
• Signs of right heart failure (peripheral edema, ascites, elevated jugular venous pressure)
• Progressive limitation of exercise capacity

Diagnostic Pathway Before Referral

Initial Assessment

Before referring, the primary care physician should:

• Confirm PH probability with echocardiography - this is the most widely used non-invasive diagnostic tool 1
• Identify and optimize treatment of underlying conditions (left heart disease, COPD, sleep apnea, pulmonary embolism) 1
• Perform basic workup including ECG, chest radiograph, pulmonary function tests with DLCO, arterial blood gases, and (NT-pro-)BNP 1, 3

When to Proceed with Referral Without Delay

Do not delay referral in the following scenarios 2, 4:

• High or intermediate probability of PH on echocardiography without confirmed left heart or lung disease
• Abnormal ventilation-perfusion (V/Q) scan suggesting CTEPH
• Clinical deterioration despite optimization of underlying conditions
• Consideration of surgical interventions (transplantation, lung volume reduction) where hemodynamic assessment is needed 1

Type of Specialist Center

Refer to a PH center with expertise in both pulmonary hypertension and lung diseases 1:

• These centers can perform right heart catheterization for definitive diagnosis and classification 1
• They have access to targeted PAH therapies and can determine treatment eligibility
• They can distinguish between PH due to lung disease versus concurrent PAH and lung disease 1, 5

Important Caveats

What NOT to Do Before Referral

• Do not initiate PAH-approved therapies in patients with PH due to left heart disease or lung disease outside of specialist centers 1
• Do not use conventional vasodilators (such as calcium channel blockers) as they may impair gas exchange and lack efficacy 1, 5
• Do not perform lung biopsy as it carries substantial morbidity/mortality risk and rarely alters management 1

Appropriate Primary Care Management Pending Referral

• Initiate long-term oxygen therapy if the patient is hypoxemic (this is the treatment of choice for PH associated with chronic lung disease) 1, 5
• Optimize treatment of underlying conditions (heart failure, COPD, sleep apnea) before considering PH-specific assessment 1

Special Populations Requiring Urgent Referral

• All patients with confirmed PAH or CTEPH must be referred to a specialist center 2
• Patients being considered for heart transplantation or left ventricular assist device implantation 1
• Patients with episodes of RV failure 1

The key principle is that "mild" PH by hemodynamic criteria may still represent severe disease requiring specialist management, particularly when symptoms are out of proportion to underlying conditions or when RV dysfunction is present.