Pulmonary Venous Hypertension: A Pulmonologist's Perspective

Abstract

Increased pulmonary hypertension (PH) awareness in the general public and among health providers has led to an increase in referral of patients who are found to have elevated estimates of pulmonary artery systolic pressure (PASP) on a transthoracic echocardiogram (TTE), without other strong features suggestive of precapillary PH (pulmonary arterial hypertension; PAH). Some of these patients undergo TTE as part of their workup for unexplained dyspnea that appears out of proportion to their other comorbidities. Many of these patients are older individuals with underlying conditions such as systemic hypertension (HTN), diabetes mellitus (DM), coronary artery disease (CAD), and obstructive sleep apnea (OSA). While some of them may have PAH, accumulated experience in the PH community suggests that many of these patients will be ultimately found to have elevated left ventricular (LV) filling pressures and impaired LV relaxation as the cause of their dyspnea and elevation of pulmonary pressures on TTE.12 These findings are consistent with a form of Group 2 PH termed LV diastolic dysfunction, more recently termed heart failure with preserved left ventricular systolic function (HFpEF) (Table 1).2 Other forms of Group 2 PH, defined as “pulmonary hypertension owing to left-sided heart disease,” include LV systolic dysfunction or left-sided valvular disease.2 For the purpose of this article, the term pulmonary venous hypertension (PVH) will be used to refer to Group 2 PH, HFpEF. Being able to accurately discriminate PAH (precapillary; Group 1 PH) from PVH (postcapillary; Group 2 PH) is critical to determine and apply the appropriate treatment course. This is a difficult, yet frequently encountered clinical dilemma, which can fall into a “gray zone” with respect to clinical classification. We will provide important clinical features that should heighten the clinician's awareness and suspicion of this rapidly growing phenomenon. These features are critical when trying to differentiate PAH (Group 1 PH) from PVH (Group 2 PH).