Pulmonary hypertension due to left heart disease (PH-LHD) is the most common in various types of pulmonary hypertension. Although there are many treatments for pulmonary hypertension, it may be harmful when we adopt treatment without detrimental diagnosis and classification of pulmonary hypertension. Therefore, it is very crucial to have accurate diagnosis and classification of pulmonary hypertension before making treatment decisions. However, there are still some difficulties in the classification of pulmonary hypertension in clinical work. It is a great challenge with limited treatment to solve the PH-LHD which often has complicated pathophysiological mechanisms of precapillary and postcapillary pulmonary hypertension. Here, we review the research status of PH-LHD.
In left heart disease, pulmonary artery pressure would increase due to the elevated left atrial pressure. This type of pulmonary hypertension (PH) is belonged to type Ⅱ as a passive PH (pPH) in its classification. The essential cause of pPH is excessive blood volume. Recently, we have identified another type of pPH, which is induced by vasopressors. Vasopressor-induced pPH shares similar pathophysiological manifestations with left heart disease-induced pPH. pPH would, therefore, be aggressive if vasopressors were applied in patients with left heart disease, which may be common after cardiac surgery, because heart undergoing surgical trauma may require support of vasopressors. Unfortunately, pPH after cardiac surgery is often ignored because of the difficulty in diagnosis. To improve the understanding of pPH and its effect on outcomes, here we highlight the mechanisms of interaction between vasopressor-induced and left heart failure-induced pPH, and provide insights into its therapeutic options.