A 75-year-old man is brought to the emergency department by paramedics following a high-speed motor vehicle accident. Several attempts are made to resuscitate him but are unsuccessful. The patient had no significant past medical history and took no medications. He was known to be in good health and tolerant of moderate levels of physical activity. Electrocardiogram findings at his last office visit showed no abnormalities. At autopsy, heavy calcifications of the aortic valve are seen. Which of the following most likely preceded the aortic valve changes observed in this patient?

Question

A 75-year-old man is brought to the emergency department by paramedics following a high-speed motor vehicle accident.  Several attempts are made to resuscitate him but are unsuccessful.  The patient had no significant past medical history and took no medications.  He was known to be in good health and tolerant of moderate levels of physical activity.  Electrocardiogram findings at his last office visit showed no abnormalities.  At autopsy, heavy calcifications of the aortic valve are seen.  Which of the following most likely preceded the aortic valve changes observed in this patient?

Quizplus · Accepted Answer

This patient's aortic valve calcifications most likely represent dystrophic calcification affecting an aging aortic valve. Dystrophic calcification is considered a hallmark of cell injury and death, occurring in all types of necrosis (eg, coagulative, fat, caseous, liquefactive) in the setting of normal calcium levels. Grossly, dystrophic calcium deposits are seen as fine, gritty, white granules or clumps. On hematoxylin and eosin staining, these deposits typically appear as dark-purple, sharp-edged aggregates. Deposits that develop lamellated outer layers are described as psammoma bodies. Dystrophic calcification in aged (or damaged) cardiac valves is thought to be the result of endothelial and fibroblast death secondary to chronic hemodynamic stress (can be accentuated by valvular abnormalities) or atherosclerotic inflammation. Subsequent release of cellular degradation products into the valvular interstitium then promotes calcification and thickening of the valve leaflets and annulus. These changes are often benign in elderly adults (aortic sclerosis); however, over time, progressive valvular stiffening can lead to outflow obstruction (calcific aortic stenosis). (Choice B) Extracellular amyloid deposition occurs in patients with amyloidosis. Amyloidosis can cause restrictive cardiomyopathy and heart failure, but it is not directly associated with calcification of the aortic valve. (Choice C) Hypercalcemia is associated with metastatic calcification affecting normal tissues and organs. In this process, calcium deposition typically occurs in more alkaline tissues involved in acid excretion, such as kidneys, lungs, systemic arteries, and gastric mucosa. (Choice D) Intracellular hemosiderin accumulation is common in patients who have hemolytic anemia or who undergo frequent blood transfusions. It is not directly associated with calcification of the aortic valve. (Choice E) Pathologic cell hypertrophy of left ventricular cardiomyocytes (ie, left ventricular hypertrophy) can occur as the result of severe aortic stenosis. Educational objective: Dystrophic calcification occurs in damaged or necrotic tissue in the setting of normal calcium levels; metastatic calcification occurs in normal tissue in the setting of hypercalcemia. __________ References: Pathogenetic mechanism of senile calcific aortic stenosis: the role of apoptosis. (http://www.ncbi.nlm.nih.gov/pubmed/11189244)

A 75-Year-Old Man Is Brought to the Emergency Department by Paramedics