Diseases Of The Aorta

1.

A 66-year-old man presents to your clinic to establish care. He has a history of hypertension and hyperlipidemia for which he takes a diuretic, an angiotensin-converting enzyme (ACE) inhibitor, and a statin. He has no complaints today and reports normal exercise tolerance without chest pain or dyspnea. Three years ago, he underwent a screening colonoscopy that was found to be normal. His family history is significant for coronary artery disease in both of his brothers and an abdominal aortic aneurysm in his father. He smokes approximately one pack of cigarettes per day and has done so for the last 30 years. On examination, his blood pressure is 130/80 mm Hg and he has mild scattered expiratory wheezes.

Which of the following screening tests is indicated in this patient?

Chest x-ray

Abdominal ultrasonography

Graded exercise test

Serum carcinoembryonic antigen

Current recommendations are for noninvasive screening of male patients older than 60 years who have a family history of aneurysm. Screening of men 65 to 75 years of age who have a history of smoking is also recommended, but there is less evidence (class IIa) in support of such screening. Screening with abdominal ultrasonography may be particularly effective for obese patients, in whom abdominal palpation is of limited value. A large-scale trial of ultrasound screening in 67,900 men 65 to 74 years of age demonstrated a reduction of 43% in aneurysm-related death in those patients who underwent routine testing. The actual cost-effectiveness of screening strategies has yet to be demonstrated.

Explanation

Current recommendations are for noninvasive screening of male patients older than 60 years who have a family history of aneurysm. Screening of men 65 to 75 years of age who have a history of smoking is also recommended, but there is less evidence (class IIa) in support of such screening. Screening with abdominal ultrasonography may be particularly effective for obese patients, in whom abdominal palpation is of limited value. A large-scale trial of ultrasound screening in 67,900 men 65 to 74 years of age demonstrated a reduction of 43% in aneurysm-related death in those patients who underwent routine testing. The actual cost-effectiveness of screening strategies has yet to be demonstrated.

2.

A 58-year-old man presents to the emergency department with abdominal and chest pain that has been present for 2 days. The pain is sharp and radiates to his midback. He has a history of hypertension but is not currently on medication. He also admits to daily crack cocaine use. On examination, he is in no distress. His blood pressure in both extremities is 210/105 mm Hg and his heart rate is 85/min. His cardiac examination is normal without murmurs, his lungs are clear, and his abdominal examination is benign. CT angiography of his chest and abdomen reveals an acute aortic dissection of the descending aorta. It does not involve the ascending aorta or the aortic arch.

Which of the following is the most common predisposing risk factor for aortic dissection?

Cocaine use

Atherosclerosis

Previous cardiac surgery

Hypertension

Key Concept/Objective: To identify the most common risk factor for aortic dissection

Risk factors for aortic dissection include hypertension, connective tissue disorders, vascular inflammation, deceleration trauma, and iatrogenic factors. In a review of 464 patients from the International Registry of Acute Aortic Dissection (IRAD), the most common predisposing factor was hypertension, followed by a history of atherosclerosis, previous cardiac surgery, and Marfan syndrome.

Explanation

Key Concept/Objective: To identify the most common risk factor for aortic dissection

Risk factors for aortic dissection include hypertension, connective tissue disorders, vascular inflammation, deceleration trauma, and iatrogenic factors. In a review of 464 patients from the International Registry of Acute Aortic Dissection (IRAD), the most common predisposing factor was hypertension, followed by a history of atherosclerosis, previous cardiac surgery, and Marfan syndrome.

3.

A 73-year-old man presents to the emergency department in a tertiary care center after the abrupt onset of "stabbing" chest pain that began 30 minutes ago. The pain radiates to his jaw and is not associated with nausea, vomiting, or shortness of breath. His past medical history is significant for coronary artery disease, hypertension, chronic kidney disease, and tobacco abuse. His medications include a beta blocker, an ACE inhibitor, a statin, and an aspirin. On examination, he appears in moderate distress. His blood pressure is 156/90 mm Hg in his right arm and 110/70 mm Hg in his left arm. He has a faint diastolic murmur at the left upper sternal border, and his lungs are clear. An electrocardiogram shows sinus tachycardia at 105 beats per minute and T wave inversions in V1 through V4. A chest radiograph shows mediastinal widening. His laboratory tests show blood urea nitrogen of 35 mg/dL and creatinine of 2.1 mg/dL. Cardiac enzymes are pending.

Which of the following is the most appropriate next step in the diagnostic management of this patient?

Transthoracic echocardiography

Magnetic resonance imaging (MRI)

Transesophageal echocardiography (TEE)

Aortography

Key Concept/Objective: To identify the appropriate imaging test in a patient with a suspected type A aortic dissection

Diagnostic imaging in patients with suspected aortic dissection aims to confirm the diagnosis, tear localization, extent of the dissection flap, and classification and determine whether emergent lifesaving intervention is needed. Currently, four diagnostic tools are used to evaluate patients with suspected dissection: multidetector computed tomographic angiography (MDCTA), echocardiography, MRI, and aortography. In general, the choice of which imaging modality to initially employ will depend on local expertise and availability. In most hospitals, the choice is either MDCTA or TEE, and the majority of patients undergo more than one imaging study. MDCTA is widely available in most community and tertiary care hospitals. MDCTA gives greater resolution than is available using the older scanners, and its reported sensitivity and specificity for aortic dissection exceed 95%. TEE offers significant advantages in diagnosis. The primary attraction of TEE is its portability, making it suitable for performance in the emergency department, intensive care unit, or operating room. In addition to being highly sensitive for the identification of type A dissection, TEE is also useful when involvement of the aortic valve and the status of the left ventricle, pericardial space, and right and left coronary artery ostia are unknown.

Explanation

Key Concept/Objective: To identify the appropriate imaging test in a patient with a suspected type A aortic dissection

Diagnostic imaging in patients with suspected aortic dissection aims to confirm the diagnosis, tear localization, extent of the dissection flap, and classification and determine whether emergent lifesaving intervention is needed. Currently, four diagnostic tools are used to evaluate patients with suspected dissection: multidetector computed tomographic angiography (MDCTA), echocardiography, MRI, and aortography. In general, the choice of which imaging modality to initially employ will depend on local expertise and availability. In most hospitals, the choice is either MDCTA or TEE, and the majority of patients undergo more than one imaging study. MDCTA is widely available in most community and tertiary care hospitals. MDCTA gives greater resolution than is available using the older scanners, and its reported sensitivity and specificity for aortic dissection exceed 95%. TEE offers significant advantages in diagnosis. The primary attraction of TEE is its portability, making it suitable for performance in the emergency department, intensive care unit, or operating room. In addition to being highly sensitive for the identification of type A dissection, TEE is also useful when involvement of the aortic valve and the status of the left ventricle, pericardial space, and right and left coronary artery ostia are unknown.

4.

A 41-year-old man presents to your clinic for a work physical examination. He takes no medications and has no complaints other than occasional foot pain, which he attributes to his "flat feet." His father died at age 50 because of a "heart problem." On examination, his blood pressure is 130/60 mm Hg and his heart rate is 80 beats per minute. He is 6 feet 4 inches tall and weighs 165 pounds. He has a high arched palate and mild pectus carinatum. On cardiac examination, there is a soft, early diastolic murmur heard best at the left upper sternal border. A transthoracic echocardiogram is ordered and reveals mild to moderate aortic insufficiency, and an aneurysm of the aortic root measured 5.4 cm in diameter.

Which of the following is the next best step in management for this patient?

Computed tomographic (CT) angiography of the chest

Beta blocker therapy and repeat transthoracic echocardiogram in 6 months

Refer for surgical repair

Dipyridamole-thallium myocardial perfusion scintigraphy

Key Concept/Objective: To recognize the indications for aortic aneurysm repair in a patient with Marfan syndrome

Currently, most thoracic centers recommend surgery for aneurysms that exceed 5.5 cm in a patient who is otherwise an acceptable surgical candidate. Because of their relatively young age, absence of associated disease, and low risk of elective repair, patients with Marfan syndrome should undergo surgery when aneurysms reach 5 cm in diameter, particularly if the aneurysm is expanding. At some high-volume centers, the threshold for elective repair of an ascending aortic aneurysm in a patient with Marfan syndrome may be even lower. As in the treatment of patients with abdominal aneurysms, the use of percutaneously placed aortic stent grafts may emerge as an attractive option in some patients with thoracic aneurysms.

The choice of surgical procedure used to correct a thoracic aortic aneurysm depends on the location of the aneurysm. Ascending aortic aneurysms are typically treated by prophylactic surgical repair. Surgery is usually recommended when the aorta has a diameter of 5.5 cm; patients with Marfan syndrome are frequently recommended for surgery when the diameter of the aorta is 5 cm.

Explanation

Key Concept/Objective: To recognize the indications for aortic aneurysm repair in a patient with Marfan syndrome

Currently, most thoracic centers recommend surgery for aneurysms that exceed 5.5 cm in a patient who is otherwise an acceptable surgical candidate. Because of their relatively young age, absence of associated disease, and low risk of elective repair, patients with Marfan syndrome should undergo surgery when aneurysms reach 5 cm in diameter, particularly if the aneurysm is expanding. At some high-volume centers, the threshold for elective repair of an ascending aortic aneurysm in a patient with Marfan syndrome may be even lower. As in the treatment of patients with abdominal aneurysms, the use of percutaneously placed aortic stent grafts may emerge as an attractive option in some patients with thoracic aneurysms.

The choice of surgical procedure used to correct a thoracic aortic aneurysm depends on the location of the aneurysm. Ascending aortic aneurysms are typically treated by prophylactic surgical repair. Surgery is usually recommended when the aorta has a diameter of 5.5 cm; patients with Marfan syndrome are frequently recommended for surgery when the diameter of the aorta is 5 cm.

5.

A 65-year-old woman is undergoing evaluation for an open surgical repair of an abdominal aortic aneurysm. She has hypertension, diabetes, and coronary artery disease; a coronary stent was placed 2 years ago, and she underwent coronary bypass surgery 6 months ago. She has been doing well since her bypass surgery and has no complaints. She does not have chest pain or shortness of breath. Her medications include insulin, aspirin, clopidogrel, metoprolol, simvastatin, and lisinopril. On examination, her blood pressure is 124/78 mm Hg and her heart rate is 66 beats/min. Her cardiac and lung examinations are normal.

Which of the following is the most appropriate next step in the management of this patient?

Her beta blocker should be continued during the perioperative period

She should undergo noninvasive stress testing prior to surgery

She should undergo coronary imaging testing prior to surgery

Both A and C

Key Concept/Objective: To understand the utility of the Revised Cardiac Risk Index and how it should be used to determine the risk for operative mortality

Patients who have had complete revascularization, in the form of coronary artery bypass grafting in the previous 5 years or percutaneous transluminal coronary angioplasty in the previous 6 months to 5 years, who are able to perform activities of daily living, and who are otherwise free of clinical symptoms of ischemia have a low likelihood of perioperative cardiac events. Usually, such patients may proceed to surgery without further cardiac testing.

A recent American College of Cardiology/American Heart Association guideline focusing on recommendations for perioperative beta blocker therapy suggested using beta blockers for the following situations: (1) beta blockers should be continued in all high-risk patients previously receiving beta blocker therapy undergoing vascular surgery; (2) beta blockers should be administered to all high-risk patients identified as having myocardial ischemia on preoperative assessment and undergoing vascular surgery; (3) beta blockers are probably recommended for high-risk patients not identified as having myocardial ischemia on preoperative assessment but defined by multiple clinical predictors undergoing intermediate- or high-risk procedures; (4) they may be considered for intermediate-risk patients defined by a single clinical predictor who are undergoing intermediate- or high-risk procedures; (5) beta blockers may be considered in low-risk patients as defined by clinical predictors who are not receiving beta blocker therapy but are undergoing vascular surgery; and (6) they should not be administered in preoperative patients with absolute contraindications to beta blockade.

Explanation

Key Concept/Objective: To understand the utility of the Revised Cardiac Risk Index and how it should be used to determine the risk for operative mortality

Patients who have had complete revascularization, in the form of coronary artery bypass grafting in the previous 5 years or percutaneous transluminal coronary angioplasty in the previous 6 months to 5 years, who are able to perform activities of daily living, and who are otherwise free of clinical symptoms of ischemia have a low likelihood of perioperative cardiac events. Usually, such patients may proceed to surgery without further cardiac testing.

A recent American College of Cardiology/American Heart Association guideline focusing on recommendations for perioperative beta blocker therapy suggested using beta blockers for the following situations: (1) beta blockers should be continued in all high-risk patients previously receiving beta blocker therapy undergoing vascular surgery; (2) beta blockers should be administered to all high-risk patients identified as having myocardial ischemia on preoperative assessment and undergoing vascular surgery; (3) beta blockers are probably recommended for high-risk patients not identified as having myocardial ischemia on preoperative assessment but defined by multiple clinical predictors undergoing intermediate- or high-risk procedures; (4) they may be considered for intermediate-risk patients defined by a single clinical predictor who are undergoing intermediate- or high-risk procedures; (5) beta blockers may be considered in low-risk patients as defined by clinical predictors who are not receiving beta blocker therapy but are undergoing vascular surgery; and (6) they should not be administered in preoperative patients with absolute contraindications to beta blockade.