Volume 13: Issue 4

In 1987, after three years of being treated aggressively for asthma and then a prolapsed mitral valve, I was finally diagnosed with primary pulmonary hypertension (PPH). I was told I would be lucky if I lived 2 years without having a heart/double lung transplant and that I didn't have much time to get my affairs in order. There were fewer than 200 patients in the United States at the time. There were no treatment centers, support groups, or even an advocacy group like the Pulmonary Hypertension Association (PHA). I struggled with the loneliness of this diagnosis and the lack of information available.

The management of acute right ventricular (RV) failure in acute pulmonary embolism (PE) differs from RV failure in chronic forms of pulmonary hypertension (PH) such as pulmonary arterial hypertension (PAH). In PE, RV failure generally occurs suddenly and there is far less ability to acutely compensate. Parameters that reflect RV function help predict outcome in PE. The mortality in acute PE leading to shock is very high; when cardiopulmonary arrest occurs, it approaches 100%.

Patients with acute PE must be risk stratified, but no perfect algorithm exists. Certain parameters are predictive of a poor prognosis and should be considered. Treatment

In the face of tremendous advances in our understanding of the pathophysiology and new treatment options, for many patients, pulmonary arterial hypertension (PAH) remains a progressive condition. The often-relentless reduction in the cross-sectional area of the pulmonary vasculature leads to progressive increase in right ventricular (RV) afterload. Although the right ventricle can adapt to an increase in afterload, progression of the pulmonary vasculopathy in PAH causes many patients to develop progressive RV failure.1 Alternately, for those with other forms of pulmonary hypertension, worsening lung disease or cardiac disease may destabilize the RV function. Acute RV decompensation may be triggered by disorders that lead to either an acute increase in cardiac demand (such as sepsis, surgery, or pregnancy), or an increase in ventricular afterload (such as an interruption in medical therapy or pulmonary embolism), or destabilization of a compensated RV (such as arrhythmia or volume overload). The poor reserve of the RV, RV ischemia, and adverse RV influence on left ventricular filling may lead to a global reduction in oxygen delivery and multi-organ failure.2 The goals of this article are to provide an approach to right heart failure in the context of an increase in its afterload. This article will focus on pathophysiologic principles on which to build an approach to medical therapies. Mechanical and surgical strategies will be the focus in the accompanying article by Dr de Perrot.

The primary function of the right ventricle (RV) is to receive systemic venous return and pump it into the normally low-pressure, highly distensible pulmonary arterial system.1 Compared to the left ventricle (LV), the RV is thinner with less mass, has 2 layers of muscles rather than 3, and has a bellow shape rather than an ellipsoid shape. Due to its typically low afterload, the metabolic demand for the RV is lower. The normal RV stroke work index is at 25% of the LV.2 Animal studies have shown that the right coronary artery flow is lower, the oxygen extraction is lower in the RV compared to the LV, and the mean RV myocardial oxygen consumption is less than half that of the LV.3 4 The study of myocardial metabolism has been dominated by studies of the LV metabolism until recently, with increasing recognition that RV performance affects patients' morbidity and mortality in patients with pulmonary hypertension5 and even in patients with left-sided heart failure.6

Memos

Editor's Memo

Pulmonary Hypertension Care Centers: Hope for the Future From a Patient's and Caregiver's Perspectives

Ask the Expert: Management of Right Ventricular Failure in Acute Pulmonary Embolism

Pathophysiologic Principles in the Management of Severe PAH

Right Ventricular Metabolism: A Brief Review

Sepsis and Pulmonary Arterial Hypertension in the ICU

Interventional Therapies for Right Ventricular Failure Secondary to Precapillary Pulmonary Hypertension

Roundtable: Pulmonary Hypertension and Right Heart Failure in the ICU: Tackling Difficult Issues

PHPN: Meeting the Challenge of Hospitalized PAH Patients Receiving IV Prostacyclins

News to Use

PHA Resources Notepad, a Tom Lantos Community Service Project

Conference Abstracts

Guest Editor’s Memo

A Roundtable Discussion Addressing Patient-Centered Care and Quality of Life in Patients With Pulmonary Arterial Hypertension

Editor’s Memo

Pulmonary Hypertension Associated With Parenchymal Lung Disease