Final answer:
Prolonged left-heart failure can cause increased pressure in the pulmonary circulation, leading to pulmonary hypertension and left sided heart failure due to the backup of blood and fluid leakage into lung tissues.
Step-by-step explanation:
Pulmonary hypertension and left sided heart failure can result from prolonged left-heart failure. When the left ventricle of the heart is unable to pump sufficient blood into the systemic circulation, this leads to an increase in pressure that backs up into the pulmonary circulation, affecting the left atrium, pulmonary veins, and eventually the pulmonary capillaries. The elevated hydrostatic pressure within these capillaries forces fluid to leak into the lung tissues, causing pulmonary edema, which can progress to pulmonary hypertension if not managed appropriately. Furthermore, heart failure is a chronic condition that can lead to the deterioration of the heart's ability to pump blood, potentially resulting in other organ failures if left untreated.