For a good quick review of pulmonary hypertension, see my post, Links To And Excerpts From 2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension
Posted on September 15, 2021 by Tom Wade MD
In this post, I link to and excerpt from The Curbsiders‘ #294 Pulmonary Hypertension Update
SEPTEMBER 13, 2021 By DEB GORTH
All that follows is from the above resource.
Pulmonary Hypertension Pearls
- Pulmonary hypertension (PH) is an increase in the pulmonary arterial pressure (defined as a mPAP > 20 mmHg (Simonneau, 2019)) caused by numerous underlying pathologies.
- PH is divided into five groups: group 1 (pulmonary arterial hypertension), group 2 (left heart disease), group 3 (lung diseases and/or hypoxia), group 4 (chronic thromboembolic pulmonary hypertension and pulmonary artery obstructions), and group 5 (multifactorial mechanism).
- The pulmonary arterial wedge pressure (PAWP) is a surrogate for what is happening on the other side of the septum (the left ventricular end diastolic pressure) during a right heart cath and can be used to differentiate pre-capillary and post-capillary PH.
- The presenting symptom of PH can be a non-specific combination of fatigue and shortness of breath. In severe PH, syncope can be the first presenting symptom..
- A V/Q scan is the gold standard for ruling out CTEPH (Tunariu, 2007).
- Pulmonary hypertension due to cardiac and pulmonary conditions can be ameliorated by addressing the underlying condition; PH secondary to heart failure should be managed with diuretics, and oxygen therapy can be useful in patients with PH caused by lung pathologies (ESC/ERS Guidelines).
- Sildenafil, tadalafil, and riociguat cannot be taken with nitrates!
Pulmonary Hypertension Infographic by Edison Jyang – #294 Pulmonary Hypertension Update with Dr. Estefania Oliveros
Pulmonary Hypertension
This is an update of our January 2018 episode, #80: Pulmonary Hypertension, freeways, and cows in heart failure.
Definition
Pulmonary hypertension (PH) is increased pulmonary arterial pressure. This increase in pressure can occur due to numerous underlying pathologies. To delineate these different etiologies, pulmonary hypertension is divided into five groups (Simonneau et al 2019):
Group 1 Pulmonary arterial hypertension (1.1 idiopathic PAH,1.2 heritable PAH, 1.3 drug/toxin induced PAH, 1.4.1 PAH associated with connective tissue disease, 1.42 HIV, 1.4.3 portal hypertension, 1.4.4 congenital heart disease, 1.4.5 schistosomiasis, 1.5 long term responders to calcium channel blockers, 1.6 PAH with features of venous/capillaries involvement, 1.7 persistent PH of the newborn)
Group 2 PH due to left heart disease (2.1 preserved LVEF, 2.2 reduced LVEF, 2.3 valvular heart disease, 2.4 congenital/acquired cardiovascular conditions with post-capillary PH)
Group 3 PH due to to lung diseases and/or hypoxia (3.1 obstructive lung disease, 3.2 mixed restrictive/obstructive lung disease, 2.4 hypoxia without lung disease, 3.5 developmental lung disease)
Group 4 PH due to pulmonary artery obstructions (4.1 chronic thromboembolic PH (CTEPH), 4.2 other pulmonary artery obstructions)
Group 5 PH with unclear and/or multifactorial mechanisms (5.1 haematological disorders, 5.2 systemic and metabolic disorders, 5.3 others, 5.4 complex congenital heart disease)
. . . the 6th World Symposium on Pulmonary Hypertension changed the haemodynamic definition of pulmonary hypertension (PH) to a mPAP > 20 mmHg (Simonneau et al 2019).
Pulmonary hypertension can also be thought of as two large groups, pre-capillary and post-capillary. Post-capillary pulmonary hypertension, the most common form of PH, is caused by elevated pressure due to left sided heart disease, causing a backup of blood and elevated right sided pressures.
Pre-capillary PH is increased pressure of pulmonary arterial system in the absence of elevated left-sided pressure. If the PAWP is ≤ 15 mmHg it is pre-capillary PH (Group 1, 3, 4, and 5). If PAWP is > 15 mmHg and PVR < 3 wood units, it is isolated post capillary PH (Group 2 and 5). If PAWP is > 15 and PVR ≥ 3 wood units it is combined pre-and post-capillary PH (Group 2 and 5) (Simonneau et al 2019). Despite this extensive classification system, patients often transcend specific pulmonary hypertension groups.
Testing for pulmonary hypertension
A right heart catheterization is required to confirm a diagnosis of PAH. The workup recommended for PH includes many common tests that you would typically order to evaluate fatigue and shortness of breath: ECG (to look for right heart hypertrophy), chest x ray (which could show pulmonary arterial dilation, right atrial enlargement, or parenchymal lung disease, though if this is strongly suspected a CT chest would better assess lung parenchyma), pulmonary function tests/overnight oximetry (to identify lung pathologies, group 3 PH), echocardiography (to look for left sided heart pathologies), CBC (which can show anemia, another cause of shortness of breath), platelets (some have hypercoagulability), LFTs, TSH (both hypothyroid and hyperthyroid can cause PH), and a V/Q scan (to rule out CTEPH)(ESC/ERS Guidelines).
Treatments
Pulmonary hypertension due to cardiac and pulmonary conditions can be ameliorated by addressing the underlying condition; PH secondary to heart failure should be managed with diuretics, and oxygen therapy can be useful in patients with PH caused by lung pathologies (ESC/ERS Guidelines). While PH specific drug therapies should be prescribed by PH specialists, it is important to understand the side effect profiles and specific considerations of PH treatments. These treatments should be continued even in hypotensive patients with PH. Stopping these medications can cause rebound pulmonary hypertension leading to right sided heart failure.
Kashlak Pearl: Stopping pulmonary hypertension medications can cause rebound pulmonary hypertension leading to right sided heart failure.
