MOC Questions

Cardiology Review® Online, August 2008, Volume 25, Issue 8

The following questions can assist candidates prepare for the Maintenance of Certification Exam in Peripheral Arterial Disease.

Preparing for the American Board of Internal Medicine Maintenance of Certification

The following questions can assist candidates prepare for the Maintenance of Certification Exam in Peripheral Arterial Disease. Feedback regarding these questions is welcomed and can be sent to editor@cardiology-review.com.

These questions were prepared by Michael W. Rich, MD.

1. In which of the following patients would current American College of Cardiology/American Heart Association practice guidelines provide a class I indication for routine abdominal ultrasonography to screen for an abdominal aortic aneurysm (AAAs)?

a) A 71-year-old woman with a 20-year history of type 2 diabetes mellitus.

b) A 73-year-old male smoker with a 40-pack-year smoking history.

c) A 63-year-old man whose older sister underwent surgical repair of an AAA 1 year earlier.

d) A 76-year-old man with hypertension and bilateral femoral artery bruits.

e) A 68-year-old woman with coronary artery disease (CAD) and intermittent claudication.

Questions 2 and 3 are based on the following case presentation:

A 74-year-old man is referred to your office for evaluation of an infrarenal AAA that was detected on a routine screening examination. He has been in generally good health, except for mild hypertension, which is well-controlled with chlorthalidone and lisinopril. The patient smoked 1 pack of cigarettes daily for 30 years, but quit smoking 25 years earlier. He is a retired construction worker, who remains active by working on various projects around his house. Physical examination reveals a well-appearing older man with a heart rate of 78 beats per minute and a blood pressure of 126/68 mm Hg. No abdominal pulsations or arterial bruits are detected. A review of his abdominal ultrasound confirms the presence of a fusiform infrarenal AAA with a maximum diameter of 4.8 cm.

2. Which of the following interventions is most appropriate at this time?

a) Initiation of a beta blocker to reduce the rate of aneurysm expansion.

b) Schedule a pharmacologic stress test to evaluate for CAD.

c) Advise the patient to avoid moderate or strenuous exertion or lifting more than 25 lb.

d) Continue present management and schedule a repeat abdominal ultrasound in 6 months.

e) Refer the patient to an interventional cardiologist for endovascular repair.

3. Serial abdominal ultrasounds performed over a 3-year period demonstrate a gradual increase in size of the AAA to 5.7 cm. The patient remains asymptomatic and active and his physical examination is unchanged; however, a pulsatile mass is now palpable in the lower abdomen. Based on this information, what do you recommend?

a) Continued observation with a repeat ultrasound in 3 months.

b) A pharmacologic stress test to assess left ventricular function and evaluate for ischemia as a prelude to aneurysm repair.

c) Coronary angiography with abdominal aortography to evaluate for CAD and to define the anatomy of the abdominal aorta and major branches.

d) Referral to a vascular surgeon for open aneurysm repair.

e) Referral to an interventional cardiologist for endovascular aneurysm repair.

Questions 4 to 6 are based on the following case presentation:

A 67-year-old hypertensive woman with a 30-pack-year history of smoking reports experiencing “cramping” pain in her left calf after walking 2 blocks. She states that she has noticed these symptoms for about 4 months, but that they seem to be getting worse. She

reports no rest pain, skin changes, or ulceration. Physical examination reveals a prominent bruit over the left femoral artery with diminished pedal pulses on the left relative to the right. There are no signs of critical limb ischemia.

4. Based on this information, you recommend that the patient undergo:

a) Assessment of the ankle-brachial index (ABI)

b) Duplex ultrasonography

c) Computed tomography (CT) angiography

d) Magnetic resonance angiography (MRA)

e) Contrast angiography

5. An ABI assessment reveals an index of 0.71 on the left and 0.96 on the right. Based on these findings, you recommend all of the following, EXCEPT:

a) Initiation of a statin to achieve a low-density lipoprotein (LDL) cholesterol level <100 mg/dL

b) Aspirin, 75 mg daily

c) A supervised exercise training program

d) Cilostazol, 100 mg twice daily

e) Referral to a vascular surgeon

6. The patient’s symptoms improve in response to the prescribed therapy; however, 4 years later, she develops worsening claudication and states that she is now able to walk only 50 feet before having to stop because of moderately severe pain. Although she reports no rest pain and the physical examination demonstrates no ulcers or gangrene, the left dorsalis pedis pulse is absent and the left posterior tibial pulse is only faintly detected. A repeat ABI assessment reveals an index of 0.35. MRA demonstrates an 85% to 90% stenosis 4 cm in length in the left superficial femoral artery with moderate distal disease, but no other high-grade lesions are identified. Based on these findings, all of the following are suitable therapeutic options, EXCEPT:

a) Continued conservative management

b) Percutaneous transluminal balloon angioplasty

c) Percutaneous angioplasty with stent placement

d) Femoral-popliteal bypass

7. In patients with critical limb ischemia, all of the following factors increase the risk of limb loss (amputation), EXCEPT:

a) Diabetes mellitus

b) Cigarette smoking

c) Severe heart failure

d) Female sex

e) Severe renal failure

Questions 8 and 9 are based on the following case presentation:

A 73-year-old retired physician is referred to your office for evaluation of resistant hypertension. The patient also has a history of hyperlipidemia and CAD, for which he underwent placement of 2 drug-eluting stents 3 years earlier. Hypertension was diagnosed 5 years before his current presentation, but it has become increasingly difficult to control over the past 2 years despite an escalating medication regimen. The patient has no history of diabetes or tobacco use. Current medications include aspirin, rosuvastatin, hydrochlorothiazide, atenolol, lisinopril, amlodipine, and clonidine. He reports strict compliance with all of his medications because he fears having a stroke. Physical examination reveals a healthy-appearing but overweight older man with a heart rate of 55 beats per minute and a blood pressure of 170/100 mm Hg in both arms. He has an S4 gallop and soft systolic ejection murmur. The remainder of the examination is unremarkable and no bruits are appreciated. Pertinent laboratory studies include a creatinine of 1.2 mg/dL and a hemoglobin of 13.3 g/dL.

8. In light of this patient’s history, you are concerned about the possibility of atherosclerotic

renovascular disease. All of the following are appropriate tests to screen for or diagnose renal artery stenosis, EXCEPT:

a) Duplex ultrasonography

b) Captopril renal scintigraphy

c) CT angiography

d) MRA

e) Contrast angiography

9. MRA demonstrates a 90% stenosis at the ostium of a large left renal artery. The patient’s kidneys are normal in size and the aorta and right renal artery are free of significant atherosclerotic disease. Based on these findings, you recommend:

a) Addition of valsartan to his medical regimen, titrated to the maximum recommended dosage

b) Percutaneous balloon angioplasty

c) Percutaneous renal stent placement

d) Vascular surgical reconstruction of the renal artery

e) Renal artery bypass grafting

10. An 83-year-old woman with chronic atrial fibrillation, mild Alzheimer’s disease, and a previous hip fracture attributed to recurrent falls presents with the sudden onset of severe abdominal pain accompanied by a single bloody bowel movement. She reports no chest pain, shortness of breath, fever, chills, nausea, or emesis. There is no history of intestinal disease, abdominal pain or surgery, and her bowel habits are usually regular. Her medications include: aspirin 81 mg/day, diltiazem SR 240 mg/day, and donepezil 5 mg/day.

Physical examination reveals an anxious elderly woman in moderate distress. She has a temperature of 37.6°C, heart rate of 95 beats per minute and irregular, and a blood pressure of 130/65 mm Hg. The cardiopulmonary examination is notable only for an irregular heart rhythm. The abdomen is mildly tender diffusely, but no masses are detected and there is no guarding or rebound on palpation. A test for occult blood in the stool is strongly positive. A complete blood count demonstrates a hemoglobin level of 11.7 g/dL and a white blood cell count of 13.2 x 103/mcL. The serum amylase level is mildly increased, but other blood chemistries are normal. An abdominal radiograph reveals a nonspecific gas pattern with no evidence of obstruction.

Based on the available information, you suspect acute intestinal ischemia resulting from an embolus arising from the left atrium. Which statement about the diagnosis and management of this condition is correct?

a) Women are affected more often than men.

b) Duplex ultrasonography is recommended as the initial diagnostic procedure.

c) Abdominal CT scanning is recommended as the initial diagnostic procedure.

d) Surgery can be deferred in most cases, unless the patient develops signs of peritonitis or infection.

e) Percutaneous revascularization procedures offer an effective alternative to surgery in most patients.

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A

nswers

1: C

The only class I indication for abdominal aortic aneurysm (AAA) screening is for men, 60 years of age or older, who are either the siblings or offspring of patients with AAAs (level B evidence). Physical examination and ultrasound screening are recommended in these patients. A class IIa indication is given for men who have a history of smoking and are between 65 and 75 years of age (level B evidence). Although men and women with coronary artery disease (CAD), lower extremity peripheral arterial disease, and long-standing diabetes mellitus may be at increased risk for AAAs, there is currently insufficient evidence to recommend routine screening in these patients.

2: D

Management of asymptomatic infrarenal AAAs measuring 4.0 to 5.4 cm in diameter involves aggressive control of blood pressure and lipids, smoking cessation (if appropriate), and serial reassessment of aneurysm size. This patient’s blood pressure is well-controlled and he has no history of hyperlipidemia. Although assessment of his lipid profile would be reasonable, no further intervention is required at this time; however, repeat abdominal ultrasonography or computed tomography (CT) scanning is indicated at 6- to 12-month intervals (class I, level A evidence). Beta blockers have not been shown to reduce the rate of aneurysm expansion and are not recommended, except for blood pressure control (class IIb, level B evidence). In the absence of chest discomfort or other symptoms of ischemia, routine stress testing to evaluate for CAD in patients with AAA is not recommended. Although avoidance of strenuous exertion and heavy lifting seems prudent, there is no evidence that curtailment of moderate activity reduces the risk of aneurysm expansion or rupture. Intervention is not recommended for asymptomatic infrarenal AAAs measuring less than 5 cm in men or less than 4.5 cm in women (class III, level A evidence).

3: D

Timely repair of infrarenal or juxtarenal AAAs measuring 5.5 cm or larger is recommended to reduce the risk of rupture, whether or not the patient is symptomatic (class I, level B evidence). In patients who are good or average surgical candidates, such as the patient described in this vignette, open surgical repair is recommended as the treatment of choice (class I, level B evidence). Endovascular repair is a reasonable therapeutic option in patients at high surgical risk secondary to major comorbid conditions (class IIa, level B evidence), but is not recommended in patients at low or average surgical risk (class IIb, level B evidence). Although patients with AAA often have concomitant CAD, there is no evidence that routine coronary revascularization before vascular surgery improves clinical outcomes, especially in the absence of symptoms; thus, routine stress testing and coronary angiography are not recommended before AAA repair in asymptomatic patients.

4: A

The patient’s history and physical examination are consistent with intermittent claudication due to lower extremity peripheral arterial disease. Current guidelines recommend assessment of the ankle-brachial index (ABI) as the initial diagnostic test in patients with intermittent claudication, in part because of the high sensitivity and low cost associated with the procedure (class I, level B evidence). If the resting ABI is normal, the measurement should be repeated after exercise. Choices B to E may be appropriate in selected patients with symptomatic lower extremity peripheral arterial disease and an abnormal ABI, but none are indicated as the initial diagnostic procedure.

5: E

The patient’s ABI confirms the presence of moderate peripheral arterial disease involving the left lower extremity; the ABI on the right is normal (normal, 0.91-1.30). In the absence of critical limb ischemia, defined as rest pain, ulceration, or gangrene, the initial therapeutic approach is aimed at aggressive treatment of cardiovascular risk factors and relief of symptoms. Symptomatic lower extremity peripheral arterial disease is a “coronary risk equivalent.” As such, treatment

with a statin to achieve a low-density lipoprotein (LDL) cholesterol level <100 mg/dL is indicated (class I, level B evidence). Smoking cessation and optimal control of hypertension and diabetes in accordance with current guidelines are also recommended. Aspirin, 75 to 325 mg daily, is indicated to reduce the risk of myocardial infarction, stroke, and vascular death (class I, level A evidence). A supervised exercise program consisting of 30- to 45-minute sessions at least 3 times per week for at least 12 weeks has been shown to improve walking distance by 50% or more and is recommended as an initial treatment for patients with intermittent claudication (class I, level A evidence). Cilostazol, a phosphodiesterase

type III inhibitor, is the only pharmacologic agent currently approved for use in the United States for which there is convincing evidence of improvement in symptoms and walking distance. Therefore, cilostazol is recommended as a reasonable therapeutic option in patients with limiting symptoms attributable to intermittent claudication (class I, level A evidence). Cilostazol is not recommended in patients with heart failure. Pentoxifylline is also approved for the treatment of intermittent claudication, but the efficacy of this agent is not well established (class IIb, level C evidence). Referral to a vascular surgeon is not indicated, except in cases of critical limb ischemia or severe limiting symptoms that do not respond to medical therapy.

6: C

In the absence of critical limb ischemia, continued conservative management remains a reasonable therapeutic option based on symptom severity, the extent to which symptoms limit activities and impair quality of life, and patient preferences. For patients with severe symptoms that do not respond satisfactorily to intensive medical therapy and supervised exercise, revascularization with either percutaneous balloon angioplasty or an arterial bypass procedure is warranted (class I, level A evidence). Primary stent placement in the femoral, popliteal, or tibial arteries is not indicated based on data from multiple randomized trials that have failed to show improved outcomes with stenting compared with angioplasty alone (class III, level C evidence).

7: D

Factors known to increase limb loss in patients with critical limb ischemia include diabetes mellitus, cigarette smoking or use of other tobacco products, severely decreased cardiac output due to severe heart failure or shock, severe renal failure, vasospastic diseases (eg, Raynaud’s phenomenon), prolonged cold exposure, infections of the distal limb (eg, cellulitis, osteomyelitis), skin breakdown, and traumatic injury. The risk of limb loss is not affected by a patient’s sex.

8: B

Duplex ultrasonography, CT angiography, and magnetic resonance angiography (MRA) are all recommended as appropriate screening tests to establish a diagnosis of renal artery stenosis (class I, level B evidence). Contrast angiography is indicated in cases where clinical suspicion is high and the results of noninvasive tests are inconclusive (class I, level B evidence). Captopril renal scintigraphy (level C evidence), selective renal vein renin measurements (level B evidence), plasma renin activity (level B evidence), and the captopril-renin test (level B evidence) are not recommended as appropriate tests to screen for renal artery stenosis because of their low sensitivity and/or specificity (all class III).

9: C

Renal artery stent placement is the procedure of choice for treatment of severe uncomplicated renal artery stenosis associated with resistant or refractory hypertension (class I-IIa, level B evidence). A single focal ostial lesion in a large renal artery provides the optimal conditions for successful stent placement. Following the procedure, most patients obtain significant clinical benefit in terms of blood pressure control; however, “cure” of hypertension is rare and some patients receive no demonstrable benefit from the procedure. Percutaneous angioplasty without stenting is the procedure of choice in young patients with renal artery stenosis secondary to fibromuscular dysplasia, but it is less effective than stenting in patients with atherosclerotic renal artery stenosis. Vascular surgical reconstruction and bypass grafting are effective treatments for renal artery stenosis, but because these procedures are more invasive, they are generally reserved for patients with more complex anatomy, such as early branching of the artery, multiple small arteries requiring intervention, or associated severe aortic atherosclerosis. The addition of an angiotensin receptor blocker (ARB), such as valsartan, is unlikely to improve blood pressure control in this patient, who is already taking 5 antihypertensive medications including an angiotensin-converting enzyme (ACE) inhibitor. In addition, the combination of an ACE inhibitor and an ARB has been associated with an increased risk of worsening renal function and hyperkalemia.

10: A

Acute intestinal ischemia is an uncommon but potentially life-threatening condition that most often occurs as a result of arterial embolization or in situ thrombosis. The condition affects twice as many women as men, and the median patient age at onset is 70 years. Most patients have preexisting cardiovascular disease. In the majority of cases, arteriography is the most useful diagnostic test and is preferable to either duplex ultrasonography or CT scanning. In patients with confirmed mesenteric artery obstruction and evidence of bowel ischemia, early surgical exploration is recommended, before the onset of peritoneal signs or evidence of infection, both of which increase perioperative mortality. Percutaneous interventions may be effective in revascularizing ischemic tissue, but do not obviate the need for surgery in patients with nonviable intestine. Moreover, restoration of blood flow to infarcted bowel as a result of either percutaneous or surgical revascularization may cause a sudden release of endotoxins into the circulation, leading to the adult respiratory distress syndrome, disseminated intravascular coagulation, and endotoxemic shock.

Source (questions 1-10)

Hirsch AT, Haskal ZJ, Hertzer NR, et al. ACC/AHA guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic): executive summary.

J Am Coll Cardiol

. 2006;47(6):1239-1312.