Pulmonary Hypertension by the Method of Paul Wood

Abstract

A physiological approach to the analysis of hemodynamic data in pulmonary hypertension (PH) has the advantage of reducing the large number (well over 100) of potential causal illnesses into four simple mechanisms. A fifth condition is composed of mixtures of the four basic mechanisms. This approach was beautifully described by Paul Wood, the great cardiologist whose name is given to the units of pulmonary vascular resistance (PVR), Wood units. This approach uses well understood physiological contributions to pulmonary vascular pressure. It is powerful, the major uncertainty being in determination of the magnitude of each mechanism in patients that have mixed PH of several causes. It also makes sense of the occasionally awkward clustering of conditions in the clinical classification of the World Symposium, which omits pulmonary vasoconstriction, hyperkinetic states, and the highly prevalent condition of "mixed" PH. This method of analysis is described and demonstrated, much as Wood did in his writings. The method is useful in the office, the ICU, and in consultation. A basic message from this approach is that correct assessment requires measurement of each of the three major inputs, pulmonary arterial pressure (Ppa), pulmonary artery wedge pressure (Pwedge) and cardiac output (CO). Some cases also need left ventricular end diastolic pressure (LVEDP). Other data contributing to analysis will be discussed in each condition. A key to avoiding mistakes is to always remember that PH is simply an elevation in pressure and is not inherently diagnostic of cause.

Normalization of Four Different Types of Pulmonary Hypertension After Atrial Septal Defect Closure

“…For the purpose of this study, the four investigated hemodynamic types of PH were defined as specified in Table 1 (2,15,17,18). IpcPH and CpcPH were distinguished by PVR, not by diastolic pressure gradient (15).…”

“…One of the causes of PAH can be congenital heart disease (CHD) with shunt (2). Although most studies on ASD with PH focus just on PAH (3,14,16), hyperkinetic PH (H-PH), characterized by normal or only modestly increased PVR (<3 WU) and normal pulmonary capillary wedge pressure (PCW ≤15 mmHg), is another type of PH described in ASD (9,17,18). Interestingly, hyperkinetic PH is currently not discussed in ESC/ERS guidelines for the diagnosis and treatment of pulmonary hypertension (2,15).…”

Topic-Based, Recent Literature Review on Pulmonary Hypertension

“…The importance of understanding the hemodynamic basis of PH and PAH as diagnosed by right-sided heart catheterization was reinforced in 2 recent reviews. 13,14 Appreciation of the pathophysiology and proper procedural technique cannot be overemphasized.…”

Comparing Diagnosis and Treatment of Pulmonary Hypertension Patients at a Pulmonary Hypertension Center versus Community Centers

“…The intent was earlier detection in the disease course; however, the frequency of diagnosis may increase, perhaps with less specificity. Notably, the diagnosis of PH encompasses a wide range of pathophysiology separated into five broad diagnostic groups, each with its own treatment pathway [ 2 , 3 ]. Diagnostic PH groups are based on the WSPH classification with group 1 consisting of pulmonary arterial hypertension (PAH), group 2 PH secondary to left heart disease, group 3 PH caused by lung diseases or hypoxia, group 4 due to chronic thromboembolic pulmonary hypertension (CTEPH), and group 5 containing PH due to uncertain causes [ 1 ].…”