Pulmonary hypertension: Difference between revisions
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[[Chest x-ray]] | [[Pulmonary hypertension CT]] | [[MRI]] | [[Echocardiography or Ultrasound]] | [[Pulmonary hypertension chest x ray|Chest x-ray]] | [[Pulmonary hypertension CT]] | [[MRI]] | [[Echocardiography or Ultrasound]] | ||
Revision as of 17:51, 12 September 2011
For patient information click here
| Pulmonary hypertension | |
| ICD-10 | I27.0, I27.2 |
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| ICD-9 | 416 |
| DiseasesDB | 10998 |
| MeSH | D006976 |
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Pulmonary Hypertension Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Pulmonary hypertension On the Web |
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American Roentgen Ray Society Images of Pulmonary hypertension |
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Risk calculators and risk factors for Pulmonary hypertension |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Richard Channick, M.D.; Assistant Editor(s)-in-Chief: Ralph Matar, Lisa Prior, Ann Slater, R.N.
Overview
Pulmonary hypertension (PH) is an increase in blood pressure in the pulmonary artery or lung vasculature, leading to shortness of breath, dizziness, fainting, and other symptoms, all of which are exacerbated by exertion. Depending on the cause, pulmonary hypertension can be a severe disease with a markedly decreased exercise tolerance and right-sided heart failure. It was first identified by Dr Ernst von Romberg in 1891.[1] It can be one of five different types, arterial, venous, hypoxic, thromboembolic, or miscellaneous.
Although the terms primary pulmonary hypertension (meaning of unknown cause) and secondary pulmonary hypertension (meaning due to another medical condition) still persist in materials disseminated to patients and the general public, these terms have largely been abandoned in the medical literature. This change has occurred because the older dichotomous classification did not reflect pathophysiology or outcome. It led to erroneous therapeutic decisions, i.e. treat "primary" pulmonary hypertension only. This in turn led to therapeutic nihilism for many patients labeled "secondary" pulmonary hypertension, and could have contributed to their deaths. The term "primary pulmonary hypertension" has now been replaced with "idiopathic pulmonary arterial hypertension". The terms "primary" and "secondary" pulmonary hypertension should not be used any longer. Further details are in the Classification section below.
Pathogenesis
Causes
History & Symptoms
Signs on Physical Examination
Diagnosis
Because pulmonary hypertension can be of 5 major types, a series of tests must be performed to distinguish pulmonary arterial hypertension from venous, hypoxic, thomboembolic, or miscellaneous varieties.
A physical examination is performed to look for typical signs of pulmonary hypertension. These include altered heart sounds, such as a widely split S2 or second heart sound, a loud P2 or pulmonic valve closure sound (part of the second heart sound), (para)sternal heave, possible S3 or third heart sound, and pulmonary regurgitation. Other signs include jugular venous distension (enlargement of the jugular veins), peripheral edema (swelling of the ankles and feet), ascites (abdominal swelling due to the accumulation of fluid), hepatojugular reflux, and clubbing.
Further procedures are required to confirm the presence of pulmonary hypertension and exclude other possible diagnoses. These generally include pulmonary function tests, blood tests, electrocardiography (ECG), arterial blood gas measurements, X-rays of the chest (followed by high-resolution CT scanning if interstitial lung disease is suspected), and ventilation-perfusion or V/Q scanning to exclude chronic thromboembolic pulmonary hypertension. Biopsy of the lung is usually not indicated unless the pulmonary hypertension is thought to be due to an underlying interstitial lung disease. But lung biopsies are fraught with risks of bleeding due to the high intrapulmonary blood pressure. Clinical improvement is often measured by a "six-minute walk test", i.e. the distance a patient can walk in six minutes. Stability and improvement in this measurement correlate with better survival.
Although pulmonary arterial pressure can be estimated on the basis of echocardiography, pressure sampling with a Swan-Ganz catheter provides the most definite measurement. PAOP and PVR can not be measured directly with echocardiography. Therefore diagnosis of PAH requires a cardiac catheterization. A Swan-Ganz catheter can also measure the cardiac output, which is far more important in measuring disease severity than the pulmonary arterial pressure.
Normal pulmonary arterial pressure in a person living at sea level has a mean value of 12–16 mm Hg (1600–2100 Pa). Definite pulmonary hypertension is present when mean pressures at rest exceed 25 mm Hg (3300 Pa). If mean pulmonary artery pressure rises above 30 mm Hg (4000 Pa) with exercise, that is also considered pulmonary hypertension.
Diagnosis of PAH requires the presence of pulmonary hypertension with two other conditions. Pulmonary artery occlusion pressure (PAOP or PCWP) must be less than 15 mm Hg (2000 Pa) and pulmonary vascular resistance (PVR) must be greater than 3 Wood units (240 dyn•s•cm-5 or 2.4 mN•s•cm-5).
Imaging
Chest x-ray | Pulmonary hypertension CT | MRI | Echocardiography or Ultrasound
Classification
Current classification
In 2003, the 3rd World Symposium on Pulmonary Arterial Hypertension was convened in Venice to modify the classification based on the new understanding of disease mechanisms. The revised system developed by this group provides the current framework for understanding pulmonary hypertension.
The system includes several improvements over the former 1998 Evian Classification system. Risk factor descriptions were updated, and the classification of congenital systemic-to pulmonary shunts was revised. A new classification of genetic factors in PH was recommended, but not implemented because available data were judged to be inadequate.
The Venice 2003 Revised Classification system can be summarized as follows:[2]
- WHO Group I - Pulmonary arterial hypertension (PAH)
- WHO Group II - Pulmonary hypertension associated with left heart disease
- WHO Group III - Pulmonary hypertension associated with lung diseases and/or hypoxemia
- WHO Group IV - Pulmonary hypertension due to chronic thrombotic and/or embolic disease
- WHO Group V - Miscellaneous
Previous terminology
The terms primary and secondary pulmonary hypertension (PPH and SPH) were formerly used to classify the disease. This led to the assumption that only the primary disease should be treated, and the secondary variety should be ignored in favor of treating only the underlying illness. In fact all forms of pulmonary arterial hypertension are treatable. Unfortunately, this classification system still persists in the minds of many physicians, and probably leads to many patients with being denied treatment. This approach to pulmonary arterial hypertension may also contribute to underdiagnosis. It is estimated that there are about 100,000 patients with PAH in the US, but only 15-20,000 have been diagnosed. Many others have been misdiagnosed as COPD, asthma, or congestive heart failure.
The term primary pulmonary hypertension (PPH) has now been replaced with idiopathic pulmonary arterial hypertension (IPAH) in much of the medical literature. However, some physicians continue to use the older classification inappropriately.