Pulmonary Hypertension Due to Left Heart Disease: Current Diagnostic Criteria and Therapeutics

Researchers at the University of Ottawa Heart Institute reviewed changes to diagnosis criteria for pulmonary hypertension (PH) due to left heart disease (LHD) and discussed therapeutic options. These perspectives were published in the Canadian Journal of Cardiology.

Prevalence of PH-LHD is not well defined despite being the most common form of PH.

Previously, PH was defined as mean pulmonary artery pressure more than 2 standard deviations above normal (³25 mmHg); however, individuals with pressures in the intermediate range were also associated with worse clinical outcomes. Recent recommendations, which came out of the sixth World Symposium on Pulmonary Hypertension held in 2018, shifted the definition of PH to mean pulmonary artery pressure greater than 20 mmHg.

PH-LHD is distinguished from PH as having concurrent elevated pulmonary artery pressure with elevated pulmonary arterial wedge pressure (>15 mmHg).

In 2013, PH-LHD was subdivided into isolated postcapillary PH (IpcPH; diastolic pulmonary gradient <7 mmHg) and postcapillary and precapillary PH (CpcPH; diastolic pulmonary gradient ³7 mmHg) phenotypes. The most recent guidelines updated the definition of IpcPH as pulmonary arterial wedge pressure greater than 15 mmHg, mean pulmonary artery pressure greater than 20 mmHg, and pulmonary vascular resistance less than 3 Wood units (WU). The new definition of CpcPH differs from IpcPH by having high pulmonary vascular resistance (³3 WU) instead of low.

The authors asserted that it may not always be necessary to determine the specific subtype of PH-LHD, but instead it is necessary to clearly define the underlying etiology before making a treatment plan, because PH-LHD is not an independent disease entity. Instead, it is a hemodynamic phenotype comprising multiple disease states.

Noninvasive imaging may allow for determining LV size, thickness, and function and right ventricular systolic function. However, patients with PH-LHD cannot avoid invasive procedures for the diagnosis and treatment of their condition. Right-heart catheterization is needed to confirm a diagnosis, and invasive hemodynamic measurements are needed for determining subtypes.

The current therapeutic approaches for PH-LHD target the precapillary or postcapillary components of the disease. Postcapillary treatments focus on the underlying cause of LHD (ie, therapies for valvular heart disease, PH-heart failure [HF] with preserved ejection fraction (or advanced HF with reduced ejection fraction), and encouraging exercise and rehabilitation.

The use of medication is not recommended for the treatment of precapillary PH-LHD, and no pulmonary arterial hypertension-specific treatment options are recommended. Some patients have disease state overlaps with HF and pulmonary arterial hypertension.

However, current scientific literature has not yielded promising results for treatment options among these patients; therefore, it remains unclear whether stratifying patients into IpcPH and CpcPH groups would lead to improved clinical outcomes.

The review authors concluded the diagnosis and management of patients with PH-LHD remains challenging due to the large heterogeneity of observed phenotypes. Additional studies are needed to better understand the biology and pathology of this condition so that more effective and personalized treatment strategies may be developed.

The study authors also cautioned that patients with PH-LHD and unexplained or persistent dyspnea, low pretest probability, risk factors of chronic pulmonary obstructive disease, and/or significant right HF should be consulted by an expert PH center.

Reference

Lee F, Mielniczuk LM. Pulmonary hypertension due to left heart disease – a practical approach to diagnosis and management. Can J Cardiol. 2020;S0828-282X(20)31104-1. doi:10.1016/j.cjca.2020.11.003