The Evolving Classification of Pulmonary Hypertension

Abstract

Context.-An explosion of information on pulmonary hypertension has occurred during the past few decades. The perception of this disease has shifted from purely clinical to incorporate new knowledge of the underlying pathology. This transfer has occurred in light of advancements in pathophysiology, histology, and molecular medical diagnostics.Objectives.-To update readers about the evolving understanding of the etiology and pathogenesis of pulmonary hypertension and to demonstrate how pathology has shaped the current classification.Data Sources.-Information presented at the 5 World Symposia on pulmonary hypertension held since 1973, with the last meeting occurring in 2013, was used in this review.Conclusions.-Pulmonary hypertension represents a heterogeneous group of disorders that are differentiated based on differences in clinical, hemodynamic, and histopathologic features. Early concepts of pulmonary hypertension were largely influenced by pharmacotherapy, hemodynamic function, and clinical presentation of the disease. The initial nomenclature for pulmonary hypertension segregated the clinical classifications from pathologic subtypes. Major restructuring of this disease classification occurred between the first and second symposia, which was the first to unite clinical and pathologic information in the categorization scheme. Additional changes were introduced in subsequent meetings, particularly between the third and fourth World Symposia meetings, when additional pathophysiologic information was gained. Discoveries in molecular diagnostics significantly progressed the understanding of idiopathic pulmonary arterial hypertension. Continued advancements in imaging modalities, mechanistic pathogenicity, and molecular biomarkers will enable physicians to define pulmonary hypertension phenotypes based on the pathobiology and allow for treatment customization.

Advances in Management of Pulmonary Hypertension Associated with Systemic Sclerosis

“…Eccentric intimal lesions of this nature have been demonstrated in lung explants from patients with severe idiopathic PAH and those with the CREST (calcinosis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasias) variant of scleroderma [22]. Vascular resistance is also increased by concentric proliferation of the endothelial cell layer creating the welldescribed "onion skin" lesion that is thought to involve myofibroblasts and smooth muscle cells (SMC), as well as endothelial cells [23,24]. Plexiform lesions consist of complex vascular networks with a myofibroblast core which distorts the vessel wall as it expands and extends into the lumen and the connective tissues surrounding the vessel [23].…”

“…Vascular resistance is also increased by concentric proliferation of the endothelial cell layer creating the welldescribed "onion skin" lesion that is thought to involve myofibroblasts and smooth muscle cells (SMC), as well as endothelial cells [23,24]. Plexiform lesions consist of complex vascular networks with a myofibroblast core which distorts the vessel wall as it expands and extends into the lumen and the connective tissues surrounding the vessel [23]. A rosary of dilated channels may form an angiomatoid, or dilation, lesion and obstruct arterial flow [25].…”

Remodulin® Pump Failure: An Emergency Medicine Simulation Scenario

“…It is defined as a mean pulmonary artery pressure of ≥25 mm Hg at rest [1]. PH includes a heterogeneous group of disorders that are differentiated based on clinical, hemodynamic, and histopathologic features including embolic, respiratory, venous, and arterial disease [2]. The estimated prevalence of PH is about 1% of the global population, which increases up to 10% in individuals above the age of 65 [3].…”

Up-regulation of nPKC Contributes to Proliferation of Pulmonary Artery Smooth Muscle Cells in Hypoxia-induced Pulmonary Hypertension

“…It is a lethal syndrome that results in the progressive increase of right ventricular load, right ventricular failure, and ultimately whole heart failure [2]. With early age of onset, numerous causes, great risks and di culties in cure, PH has attracted much attention in the world, and was currently divided into ve categories, including: pulmonary arterial hypertension (PAH), pulmonary hypertension due to left heart disease, hypoxic pulmonary hypertension, chronic thromboembolic pulmonary hypertension, and PH with unclear and/or multifactorial mechanisms, of which HPH is the most common [3].…”