Right ventricular heart failure from pulmonary embolism: key distinctions from chronic pulmonary hypertension.
BACKGROUND
The right ventricle normally operates as a low pressure, high-flow pump connected to a high-capacitance pulmonary vascular circuit. Morbidity and mortality in humans with pulmonary hypertension (PH) from any cause is increased in the presence of right ventricular (RV) dysfunction, but the differences in pathology of RV dysfunction in chronic versus acute occlusive PH are not widely recognized.


RESULTS
Chronic PH that develops over weeks to months leads to RV concentric hypertrophy without inflammation that may progress slowly to RV failure. In contrast, pulmonary embolism (PE) results in an abrupt vascular occlusion leading to increased pulmonary artery pressure within minutes to hours that causes immediate deformation of the RV. RV injury is secondary to mechanical stretch, shear force, and ischemia that together provoke a cytokine and chemokine-mediated inflammatory phenotype that amplifies injury.


CONCLUSIONS
This review will briefly describe causes of pulmonary embolism and chronic PH, models of experimental study, and pulmonary vascular changes, and will focus on mechanisms of right ventricular dysfunction, contrasting mechanisms of RV adaptation and injury in these 2 settings.
Watts
John A
JA
Emergency Medicine Research, Carolinas Medical Center, 1542 Garden Terrace, Charlotte, NC 28203, USA. jwatts@carolinas.org
Marchick
Michael R
MR
Kline
Jeffrey A
JA
D000208:Acute Disease; D000818:Animals; D002908:Chronic Disease; D018450:Disease Progression; D006333:Heart Failure / Q000209:etiology* / Q000401:mortality / Q000473:pathology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications* / Q000175:diagnosis; D017380:Hypertrophy, Right Ventricular / Q000209:etiology* / Q000401:mortality / Q000473:pathology; D007150:Immunohistochemistry; D011379:Prognosis; D011655:Pulmonary Embolism / Q000150:complications* / Q000175:diagnosis; D016019:Survival Analysis; D018497:Ventricular Dysfunction, Right / Q000209:etiology* / Q000401:mortality / Q000473:pathology