Atherosclerosis

Atheroembolism of cerebral arteries with following transient ischemic attack is the correct answer. Atheromatous emboli are usually small and are rapidly lysed in the blood stream

A 75-year-old man is brought to an urban hospital from his rural home over fifty miles away. He reportedly collapsed on rising from his couch to go answer his doorbell. He had slurred speech, twisting of the face, and weakness of the left side of his body. Upon arrival to the hospital, there is no twisting of the face, patient speech is slowed but not slurred, and there is no significant difference in power between the left and right limbs. Vital signs are: PR of 85 bpm, RR of 22 bpm, and BP of 140/85 mm Hg. The lung fields are clear on auscultation. Which of the following is the most likely cause of patient symptoms? A psychologic disorder Thromboembolism of cerebral arteries with following ischemic cerebral infarction Hemorrhagic stroke Atheroembolism of cerebral arteries with following transient ischemic attack

Thin fibrous cap and necrotic lipid core is the correct answer. A vulnerable atheromatous plaque has a thin fibrous cap, large lipid core, and increased inflammation. Plaques with thin fibrous caps and active inflammatory cells over a necrotic core are more likely to rupture. Computed tomography coronary angiography is a noninvasive imaging method to assess arterial narrowing and plaque composition. An acute coronary syndrome from sudden occlusion can result from plaque rupture, overlying thrombosis, and/or plaque hemorrhage. Embolization to a coronary artery or from a coronary plaque is not as common an event as acute plaque changes; most clinically significant emboli come from large mural thrombi in left atrium or ventricle. Calcification, increased smooth muscle with extracellular matrix, and a thick fibrous cap are features of more stable plaques.

Question 10 1 / 1 pts A 59-year-old woman with type 2 diabetes mellitus experiences an episode of chest pain with exercise. On examination, her BMI is 30 kg/m2. Angiography reveals proximal coronary arterial narrowing with up to 70% stenosis. Which of the following changes in the region of narrowing is most likely to increase her risk for an acute coronary syndrome? Medial calcification Thick and calcified fibrous cap Thin fibrous cap and necrotic lipid core Atheroembolism Smooth muscle proliferation

Atherosclerotic aneurysm is the correct answer. A vulnerable atheromatous plaque has a thin fibrous cap, a large lipid core, and increased inflammation. Plaques with thin fibrous caps and active inflammatory cells over a necrotic core are more likely to rupture. Computed tomography coronary angiography is a noninvasive imaging method to assess arterial narrowing and plaque composition. An acute coronary syndrome from sudden occlusion can result from plaque rupture, overlying thrombosis, and/or plaque hemorrhage. Embolization to a coronary artery or from a coronary plaque is not as common an event as acute plaque changes; most clinically significant emboli come from large mural thrombi in the left atrium or ventricle. Calcification, increased smooth muscle with extracellular matrix, and a thick fibrous cap are features of more stable plaques.

Question 11 1 / 1 pts An 84-year-old man with a lengthy history of smoking survived a small myocardial infarction 2 years ago. He now reports chest and leg pain during exercise. On physical examination, his vital signs are temperature, 37.1°C (98.8°F); pulse, 81/min; respirations, 15/min; and blood pressure, 165/100 mm Hg. Peripheral pulses are poor in the lower extremities. There is a 7-cm pulsating mass in the midline of the lower abdomen. Laboratory studies include two fasting serum glucose measurements of 170 and 200 mg/dL. Which of the following vascular lesions is most likely to be present in this patient? Thromboangiitis obliterans Atherosclerotic aneurysm Arteriovenous fistula Aortic dissection Polyarteritis nodosa Takayasu arteritis

Abdominal aortic aneurysm is the correct answer. A vulnerable atheromatous plaque has a thin fibrous cap, large lipid core, and increased inflammation. Plaques with thin fibrous caps and active inflammatory cells over a necrotic core are more likely to rupture. Computed tomography coronary angiography is a noninvasive imaging method to assess arterial narrowing and plaque composition. An acute coronary syndrome from sudden occlusion can result from plaque rupture, overlying thrombosis, and/or plaque hemorrhage. Embolization to a coronary artery or from a coronary plaque is not as common an event as acute plaque changes; most clinically significant emboli come from large mural thrombi in left atrium or ventricle. Calcification, increased smooth muscle with extracellular matrix, and a thick fibrous cap are features of more stable plaques.

Question 12 1 / 1 pts A 41-year-old man has had worsening abdominal pain for the past week. On physical examination, his vital signs are temperature, 36.9°C (98.4°F); pulse, 77/min; respirations, 16/min; and blood pressure, 140/90 mm Hg. An abdominal ultrasound reveals the findings in the figure. path_of_arthros_q11.jpg Which of the following is the most likely underlying disease process in this patient? Diabetes mellitus Syphilis Systemic lupus erythematosus Abdominal aortic aneurysm Marfan syndrome

Marfan syndrome is the correct answer. The figure shows disruption of the thin black medial elastic fibers, typical for cystic medial degeneration, which weakens the aortic media and predisposes to aortic dissection. In a young patient a heritable disorder of connective tissues, such as Marfan syndrome, must be strongly suspected. Scleroderma and anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (granulomatosis with polyangiitis) do not typically involve the aorta. Atherosclerosis associated with diabetes mellitus and hypertension are risk factors for aortic dissection, although these are more often seen at an older age. Takayasu arteritis is seen mainly in children and involves the aorta (particularly the arch) and branches such as the coronary and renal arteries, causing granulomatous inflammation, aneurysm formation, and dissection.

Question 13 1 / 1 pts A 23-year-old man experiences sudden onset of severe, sharp chest pain. On physical examination, his temperature is 36.9°C (98.4°F), and his lungs are clear on auscultation. A chest radiograph shows a widened mediastinum. Transesophageal echocardiography shows a dilated aortic root and arch, with a tear in the aortic intima 2 cm distal to the great vessels. The representative microscopic appearance of the aorta with elastic stain is shown in the figure. path_of_arthros_q13.jpg Which of the following diseases is the most likely cause of these findings? Takayasu arteritis Diabetes mellitus, type 2 ANCA-associated vasculitis Scleroderma, diffuse Systemic hypertension Marfan syndrome

Dissection is the correct answer. A sudden tear in the proximal aortic intima allows blood to enter the space between layers within the wall of the aorta. This blood may pass through the aortic wall, around great vessels, and into the pericardial cavity, as in this case with cardiac tamponade. Blood may enter the chest cavity, causing hemothorax. Hypertension is the most common risk factor for aortic dissection. In contrast, a false aneurysm is characterized by formation of a hematoma by extravasated blood, but it communicates with the vascular lumen; a true aneurysm includes all three layers of the arterial wall. Arteriolosclerosis can be associated with hypertension, but it involves arterioles, typically in kidneys, not the aorta. Thrombosis of extravasated blood from a dissection can occur, but this is not the primary lesion. Vasculitis does not often involve the aorta, but giant cell arteritis and Takayasu arteri

Question 14 1 / 1 pts A 59-year-old man experiences sudden severe chest pain that radiates to his back. On physical examination, his blood pressure is 170/110 mm Hg. Heart sounds are distant. Pulsus paradoxus is observed. A pericardiocentesis is performed and yields blood. Which of the following pathologic findings has most likely occurred in his aorta? Dissection Thrombosis Aneurysm Vasculitis Arteriolosclerosis

Pulmonary thromboembolism is the correct answer. Pulmonary thromboembolism is not a complication of abdominal aortic aneurysm

Question 2 1 / 1 pts A 65-year-old man has sudden onset of severe abdominal pain that has persisted for the past three hours. Vital sings: body temperature of 37.0˚ C, pulse of 110 bpm, BP of 155/95 mm Hg, and RR of 25 bpm. Physical examination reveals diminished pulses in the lower extremities and a pulsative abdominal mass. Which of the following complications is LEAST likely to be seen in this condition? Ischemia of the lower extremities Compression of adjacent structures (mass/pressure effect) Rupture/leakage Pulmonary thromboembolism Thrombosis

2-to-3 cm transverse intimal tear is the correct answer. Aortic dissection usually occurs in the proximal ascending aorta and is not associated with preceding atherosclerosis; cystic medial degeneration is a MICROSCOPIC, not a gross sign of aortic pathology

Question 3 1 / 1 pts 53-year-old man complains of severe, "tearing" chest pain on presentation to the medical emergency department. His vital signs are: body temperature of 36.6˚ C, pulse of 90 bpm, RR of 20 bpm, and BP of 130/75 mm Hg. EKG shows mild ischemic changes in the septum and the anterior wall of the left ventricle. Imaging studies reveal a proximal double-lumen aorta and changes consistent with cystic medial necrosis. Which of the following GROSS pathologic changes would most likely be observed in the proximal ascending aorta of the patient? Cystic medial degeneration 2-to-3 cm transverse intimal tear Calcified atherosclerotic plaque Significant dilation of the aortic lumen Fatty streaks

Media is the correct answer. The ankle-brachial index (ABI) is a test for peripheral artery disease that can lead to claudication (pain) with exercise. The most likely cause is atherosclerosis which begins in the intima from endothelial injury with secondary weakness of the media, then proceeds with monocytes becoming macrophages, transforming to foam cells, and accompanied by smooth muscle cell proliferation. This man has two risk factors for atheroma formation: hypercholesterolemia and smoking. The other listed foils are not going to affect blood pressure as much as media, which helps conduct the pulse pressure from cardiac contractions to the periphery. Pericytes are contractile cells present at intervals along the walls of capillaries that aid in shunting blood to capillary beds.

Question 4 1 / 1 pts A 51-year-old man has noted pain in his legs when he walks more than 1 km. He has a history of hypercholesterolemia. He smokes a pack of cigarettes per day. On examination his dorsalis pedis pulses are weaker than his radial pulses. His blood pressure in arm and ankle are measured. The ratio of blood pressure in the lower extremity versus upper extremity is 0.85. This clinical picture is most likely caused by a disease affecting which of the following components of his vasculature? Internal elastic lamina External elastic lamina Media Adventitia Pericytes

An incidental observation is the correct answer. Older adults with radiographic evidence of calcified arteries often have Mönckeberg arteriosclerosis, beginning in the internal elastic lamina. This is a benign process that is a form of arteriosclerosis, often with no serious sequelae. The distal extremities, pelvis, thyroid, and breast regions are the most common locations. Such focal peripheral arterial calcification is far less likely to be a consequence of atherosclerosis, with diabetes mellitus or with hypercalcemia. Hypertension is most likely to affect small renal arteries, with hyaline or hyperplastic arteriolosclerosis, and calcification is not a major feature, although hypertension also is a risk factor for atherosclerosis. In descending order, the vessels most involved with atherosclerosis, particularly at branch points, are the lower abdominal aorta and iliac arteries, coronary arteries, popliteal arteries

Question 5 1 / 1 pts A 57-year-old woman experiences mild intermittent right hip pain after falling down a flight of stairs. Physical examination shows a 3-cm contusion over the right hip. The area is tender to palpation, but she has full range of motion of the right leg. A radiograph of the pelvis and right upper leg shows no fractures, but does show calcified, medium-sized arterial branches in the pelvis. This radiographic finding is most likely to represent which of the following? Benign essential hypertension An incidental observation Long-standing diabetes mellitus Increased risk for gangrenous necrosis Unsuspected hyperparathyroidism

Endothelial dysfunction is the correct answer. He has multiple risk factors for atherogenesis involving coronary arteries, initiated by endothelial injury or dysfunction, followed by migration of smooth muscle cells into the intima. These cells then proliferate and synthesize ECM, forming a neointima that initially is covered by intact endothelium. Adventitial inflammation may occur with some infectious or immune processes but does not initiate atherogenesis. Cystic medial degeneration can result from inherited diseases such as Marfan syndrome and can also be idiopathic; they can lead to aortic dissection. Some forms of vasculitis can result from deposition of immune complexes.

Question 6 1 / 1 pts A 71-year-old man has noted chest pain when climbing a flight of stairs, worsening over the past 5 months. On examination his blood pressure is 145/95 mm Hg. Laboratory studies show an elevated Hgb A1C and LDL cholesterol. Which of the following vascular abnormalities most likely initiated the events leading to his chest pain? Adventitial inflammation Dissection into the media Endothelial dysfunction Immune complex deposition Cystic medial degeneration

Oxidized LDL is the correct answer. Oxidized LDL can be taken up by a special "scavenger" pathway in macrophages; it also promotes monocyte chemotaxis and adherence. Macrophages taking up the lipid become foam cells that begin to form the fatty streak. Smoking, diabetes mellitus, and hypertension all promote free radical formation, and free radicals increase degradation of LDL to its oxidized form. About one-third of LDL is degraded to the oxidized form; a higher LDL level increases the amount of oxidized LDL available for uptake into macrophages. C-reactive protein is a marker for inflammation, which can increase with more active atheroma and thrombus formation and predicts a greater likelihood of acute coronary syndromes. Increased homocysteine levels promote atherogenesis through endothelial dysfunction. Lp(a), an altered form of LDL that contains the apo B-100 portion of LDL linked to apo A, promotes lipid accumu

Question 7 1 / 1 pts An experiment studies early atheroma development. Lipid streaks on arterial walls are examined microscopically and biochemically to determine their cellular and chemical constituents and the factors promoting their formation. Early lesions show increased attachment of monocytes to endothelium. The monocytes migrate subendothelially and become macrophages; these macrophages transform themselves into foam cells. Which of the following substances is most likely to be responsible for the transformation of macrophages? Lp(a) Oxidized LDL Very low density lipoprotein (VLDL) C-reactive protein Homocysteine Platelet-derived growth factor

Endothelial dysfunction is the correct answer. Atherosclerosis is thought to result from an initial endothelial injury and the subsequent chronic inflammation and repair of the arterial intima. All risk factors, including smoking, hyperlipidemia, and hypertension, cause biochemical or mechanical injury to the endothelium with resulting dysfunction that initiates smooth muscle migration with proliferation, as well as lymphocyte and monocyte-macrophage infiltration. Formation of foam cells occurs after the initial endothelial injury. Vasomotor tone does not play a major role in atherogenesis. Inhibition of LDL oxidation should diminish atheroma formation. Although lipoprotein receptor alterations can occur in some inherited conditions, these account for only a fraction of cases of atherosclerosis, and other lifestyle conditions do not affect their action.

Question 8 1 / 1 pts A 50-year-old man has a 2-year history of angina pectoris that occurs during exercise. On physical examination, his blood pressure is 135/75 mm Hg, and his heart rate is 79/min and slightly irregular. Coronary angiography shows a fixed 75% narrowing of the anterior descending branch of the left coronary artery. He has several risk factors for atherosclerosis: smoking, hypertension, and hypercholesterolemia. Which of the following is the earliest event resulting from the effects of these factors? Modification of hepatic lipoprotein receptors Alteration in vasomotor tone regulation Conversion of smooth muscle cells to foam cells Inhibition of LDL oxidation Endothelial dysfunction

Plaque rupture is the correct answer. Her acute coronary syndrome is a consequence of advanced atherogenesis, and when the plaque ruptures, thrombogenesis is initiated that can further reduce the arterial lumen to promote ischemia with infarction. The plaques responsible for acute coronary syndromes often are asymptomatic prior to thrombosis on a lesion that previously did not produce significant luminal occlusion. Foam cell accumulation of lipids and T-lymphocyte release of cytokines are both part of a long process of plaque formation, not a complication. Accumulation of calcium is slow, often in a stable plaque. A thrombosed artery can heal by recanalization to restore some blood flow.

Question 9 1 / 1 pts A 57-year-old woman has a 30-year history of poorly controlled diabetes mellitus. She has had no major medical problems. Now, over the past 3 hours, she has developed sudden severe chest pain. An ECG shows ST segment elevation. Her serum troponin is elevated. Which of the following pathologic changes most likely initiated her acute event? Plaque rupture Inflammation Accumulation of foam cells Calcium deposition Luminal recanalization