Progress in cardiovascular diseases
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Prog Cardiovasc Dis · Sep 2012
ReviewRight ventricular assist device in end-stage pulmonary arterial hypertension: insights from a computational model of the cardiovascular system.
The high mortality rate of pulmonary arterial hypertension (PAH) mainly relates to progressive right ventricular (RV) failure. With limited efficacy of medical therapies, mechanical circulatory support for the RV has been considered. However, there is lack of understanding of the hemodynamic effects of mechanical support in this setting. ⋯ The results of this theoretical analysis suggest that RVAD support can effectively increase cardiac output and decreases RA pressure with the consequence of increasing pulmonary artery and capillary pressures. Especially in advanced PAH, low RVAD flow rates may mitigate these potentially detrimental effects while effectively increasing systemic hemodynamics.
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Prog Cardiovasc Dis · Sep 2012
ReviewPulmonary hypertension and right ventricular dysfunction in left heart disease (group 2 pulmonary hypertension).
Group 2 pulmonary hypertension is most frequently caused by left heart disease, a heterogeneous set of disorders. These processes include left ventricular systolic dysfunction, left ventricular dysfunction with preserved ejection fraction and valvular (mitral and/or aortic) diseases. Left heart disease may cause passive backward transmission of pressure leading to elevated left atrial and pulmonary arterial pressures due to a myriad of processes. ⋯ This is believed to be due to increases in vasomotor tone and/or vascular remodeling. Over time patients may go on to develop progressive right ventricular dysfunction, a marker for poor prognosis. This review will explore the different characteristics of these conditions including the incidence, pathophysiology, clinical implications, prognosis and current state of available medical therapies.
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The lungs are the only organ that receives the entire cardiac output with every stroke. The pulmonary circulation is normally a high-flow, low-resistance, low-pressure system that carries blood into the pulmonary microcirculation. ⋯ The functional status of the pulmonary circulation and the levels of PVR and PAP ultimately determine the outcome of patients with PAH. Study of the pressure-flow relationships in the pulmonary vascular bed will provide an improved appreciation of the pathophysiology of pulmonary hypertension.
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Anesthesia and surgery are associated with significantly increased morbidity and mortality in patients with pulmonary hypertension due mainly to right ventricular failure, arrhythmias, postoperative hypoxemia, and myocardial ischemia. Preoperative risk assessment and successful management of patients with pulmonary hypertension undergoing cardiac surgery involve an understanding of the pathophysiology of the disease, screening of patients at-risk for pulmonary arterial hypertension, analysis of preoperative and operative risk factors, thorough multidisciplinary planning, careful intraoperative management, and early recognition and treatment of postoperative complications. This article will cover each of these aspects with particular focus on the anesthetic approach for non-cardiothoracic surgeries.