Vasoreactivity Testing in VSD with Pulmonary Hypertension
No, vasoreactivity testing is NOT recommended in this patient with VSD-associated pulmonary hypertension. The ESC/ERS guidelines explicitly state that vasoreactivity testing to detect patients who can be safely treated with high doses of calcium channel blockers is not recommended in patients with PAH other than idiopathic PAH (IPAH), heritable PAH (HPAH), and PAH associated with drug use 1.
Why Vasoreactivity Testing is Not Indicated
VSD-associated PAH is classified as congenital heart disease-associated PAH (CHD-PAH), which falls outside the approved indications for vasoreactivity testing. The guidelines provide a Class III recommendation (meaning it should not be done) for vasoreactivity testing in PAH groups other than IPAH, HPAH, and drug-induced PAH 1.
Key Guideline Recommendations
The ESC/ERS guidelines are clear and unequivocal on this point:
- Vasoreactivity testing is recommended ONLY in patients with IPAH, HPAH, and PAH associated with drug use to identify candidates for high-dose calcium channel blocker therapy 1
- Testing is NOT recommended in other PAH subtypes including congenital heart disease-associated PAH 1
- Testing is NOT recommended in PH groups 2,3,4, and 5 1
Clinical Context of Your Patient
Your patient presents with:
- VSD with high flow, low resistance physiology
- Moderate PH with mPAP 42 mmHg
- Extremely low PVR of 0.2 WU (normal is <3 WU)
- Very low PVR/SVR ratio of 0.03
This hemodynamic profile indicates a high-flow state with minimal pulmonary vascular disease, not the fixed pulmonary vascular remodeling seen in idiopathic PAH. The extremely low PVR (0.2 WU) suggests the pulmonary hypertension is primarily flow-mediated rather than due to pulmonary vascular disease 1.
Management Approach for VSD-Associated PH
The appropriate next step is assessment for VSD closure, not vasoreactivity testing. The guidelines specifically recommend that RHC is indicated in patients with congenital cardiac shunts to support decisions on correction 1.
Decision-Making for VSD Closure
With your patient's hemodynamics:
- PVR of 0.2 WU is well below the threshold of concern (typically PVR >3 WU raises concerns about operability) 1
- The PVR/SVR ratio of 0.03 is extremely favorable (ratios <0.3 generally indicate operability)
- These values suggest the patient may be a candidate for VSD closure rather than medical PAH therapy
Common Pitfalls to Avoid
Do not perform vasoreactivity testing in CHD-associated PAH patients. This is a common error that:
- Provides no clinically useful information for treatment decisions 1
- Exposes patients to unnecessary procedural risks 1
- Does not identify candidates for calcium channel blocker therapy in this population 1
The role of vasoreactivity testing is specifically to identify the small subset (~10%) of IPAH patients who can be treated with high-dose calcium channel blockers as monotherapy 1, 2. This therapeutic strategy does not apply to CHD-associated PAH 1.
What Testing IS Indicated
Right heart catheterization (which you have already performed) is the appropriate test to:
- Confirm the diagnosis and severity of PH 1
- Support decisions regarding VSD correction 1
- Calculate PVR and assess operability 1
Your patient's hemodynamics with extremely low PVR suggest the primary issue is the left-to-right shunt creating high pulmonary blood flow, not intrinsic pulmonary vascular disease requiring PAH-specific medical therapy.