Chest
CommentaryPulmonary “Capillary” Wedge Pressure Not the Pressure in the Pulmonary Capillaries
Section snippets
MODEL
The difference between the PAWP and the pulmonary capillary pressure can be understood by realizing that the PAWP is actually a distorted measure of the pressure in the pulmonary veins. Figure 1A illustrates measurement of the PAWP. When the artery is occluded, blood flow in the segment distal to the occlusion ceases, as is illustrated by the shaded area (Fig 1A). Because there is no flow in the occluded segment, pressure everywhere in this segment is the same. There is a single outlet where
CLINICAL CORRELATION
In addition to experimental evidence that the PAWP is not capillary pressure, there is also a disease which demonstrates this fact: pulmonary veno-occlusive disease (PVOD). This disease was initially described in the 1930s.12,13 It is a disease of unknown cause which is manifested by progressive dyspnea and cyanosis and is usually fatal a few years after symptoms first appear. It is characterized by the triad of severe pulmonary arterial hypertension, pulmonary congestion with Kerley's B lines
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Cited by (26)
Pulmonary Hypertension Caused by Fibrosing Mediastinitis
2022, JACC: AsiaCitation Excerpt :Right heart catheterization (RHC) is the gold standard for diagnosing PH. PH-FM mostly belongs to precapillary PH.2 Although some patients have PV stenosis, their PA wedge pressure measured by Swan-Ganz catheter is mostly normal. This is because the involved PVs are predominantly located at the proximal first drainage branches, which are usually smaller in size than the balloon of a Swan-Ganz catheter.67 This scenario is comparable to the apparently normal PA wedge pressure exhibited during PV occlusive disease.68
Congenital Heart Disease: A Clinical, Pathological, Embryological, and Segmental Analysis
2022, Congenital Heart Disease: A Clinical, Pathological, Embryological, and Segmental AnalysisPulmonary veno-occlusive disease: An important consideration in patients with pulmonary hypertension
2017, Respiratory MedicineCitation Excerpt :However, the PAOP in patients with POVD can be mildly elevated; if it is markedly elevate, the hemodynamic profile supports the diagnosis of WHO Group 2 pulmonary hypertension. The normal PAOP in PVOD is due to the fact that small venules and capillaries are primarily involved with relative sparing of larger veins and the wedged pulmonary artery catheter measures pressures in the larger pulmonary veins and does not measure pressures in small pulmonary venules or capillaries [5,42,52]. An elevated PAOP requires both blood flow into the downstream circuit distal to the catheter tip and proximal to the level of the obstruction, and there must be no run-off of blood around the site of the obstruction.
Pulmonary Veno-occlusive Disease
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From the Division of General Internal Medicine, Ohio State University School of Medicine, Columbus.