A 56-year-old man comes to the emergency department due to progressively worsening dyspnea. The patient can walk only a few blocks before becoming short of breath. He also finds it difficult to sleep lying flat and requires 3 pillows to prop himself upright when sleeping. Other medical problems include long-standing hypertension, for which he occasionally takes his prescribed antihypertensive medication. The patient does not use tobacco, alcohol, or illicit drugs. Blood pressure is 170/100 mm Hg, and pulse is 80/min and regular. Physical examination reveals bilateral basilar lung crackles, jugular venous distension, and bilateral lower extremity edema. Chest x-ray reveals cardiomegaly and hilar prominence. ECG shows left ventricular hypertrophy. Echocardiogram shows elevated pressures in the pulmonary artery. Which of the following is the most likely underlying cause of the observed echocardiographic finding in this patient?

Question

A 56-year-old man comes to the emergency department due to progressively worsening dyspnea.  The patient can walk only a few blocks before becoming short of breath.  He also finds it difficult to sleep lying flat and requires 3 pillows to prop himself upright when sleeping.  Other medical problems include long-standing hypertension, for which he occasionally takes his prescribed antihypertensive medication.  The patient does not use tobacco, alcohol, or illicit drugs.  Blood pressure is 170/100 mm Hg, and pulse is 80/min and regular.  Physical examination reveals bilateral basilar lung crackles, jugular venous distension, and bilateral lower extremity edema.  Chest x-ray reveals cardiomegaly and hilar prominence.  ECG shows left ventricular hypertrophy.  Echocardiogram shows elevated pressures in the pulmonary artery.  Which of the following is the most likely underlying cause of the observed echocardiographic finding in this patient?

Quizplus · Accepted Answer

11ec160b_3b47_b81f_9249_1bf413fa82ff_MD0001_00 This patient with dyspnea, orthopnea, and pulmonary crackles has left-sided heart failure (LHF) most likely due to long-standing, poorly controlled hypertension. Hypertensive heart disease typically manifests as heart failure due to concentric left ventricular (LV) hypertrophy and consequent LV diastolic dysfunction. LHF of any cause (eg, LV systolic dysfunction, valvular dysfunction) will result in higher diastolic filling pressures. This increase in pressure is transmitted backward to the left atrium and pulmonary veins, resulting in pulmonary venous congestion and consequent elevations in pulmonary capillary and pulmonary arterial pressure. The resulting pulmonary hypertension (PH) can lead to right-sided heart failure with jugular venous distension and peripheral edema. Over time, remodeling of the pulmonary vasculature occurs with increased smooth muscle cell proliferation (medial hypertrophy) and collagen deposition (intimal thickening and fibrosis). The remodeling is less extensive than in (primary) pulmonary arterial hypertension; therefore, the PH is at least partially reversible with treatment of the LHF. (Choices A and E) Hypoxia-induced vasoconstriction and emphysematous obliteration of the vasculature underlie PH that occurs secondary to chronic obstructive pulmonary disease. Although there is a small component of hypoxia-induced pulmonary vasoconstriction in LHF, pulmonary venous congestion is the major cause of PH. (Choice B) Congenital heart disease that causes left-to-right shunting (eg, ventricular septal defect, atrial septal defect) can lead to PH via an increase in pulmonary arterial blood flow. In LHF, PH occurs due to backwards transmission of pressure from increased pulmonary venous blood volume; pulmonary arterial blood flow remains the same or decreases as LHF worsens. (Choice D) Inflammatory large-vessel vasculitis (ie, Takayasu arteritis, giant cell arteritis) can sometimes involve the pulmonary arteries and cause PH. However, pulmonary vascular inflammation does not play a role in PH occurring secondary to LHF. (Choice F) Thrombotic obstruction of the pulmonary arterial tree occurs in acute pulmonary embolism, and some patients can develop chronic thromboembolic PH despite receiving appropriate anticoagulation therapy. However, this patient has no history of thromboembolic disease, and his orthopnea and crackles are more suggestive of PH due to LHF. Educational objective: Left-sided heart failure can cause secondary pulmonary hypertension via elevated left-sided diastolic filling pressures transmitting backward to the pulmonary veins, resulting in pulmonary venous congestion. Over time, pulmonary arterial remodeling (medial hypertrophy and intimal thickening with fibrosis) can occur, but not to the extent that occurs in (primary) pulmonary arterial hypertension. __________ References: Pulmonary hypertension in left heart disease. (http://www.ncbi.nlm.nih.gov/pubmed/23204122)

A 56-Year-Old Man Comes to the Emergency Department Due to Progressively