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Old 10-21-2011
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Default Cardiology

A 76-year-old man is brought to the emergency department after a motor vehicle accident and complains of a headache. He immediately gets a head CT scan that reveals a moderate-sized subdural hematoma. Neurosurgeons wish to take him to the operating room for an evacuation, and request medical clearance for the procedure. The patient denies chest pain, although his exercise tolerance has been limited. He is able to climb a flight of steps without difficulty. He has a history of diabetes and hypertension. His medications include lisinopril 10 mg daily. He is a smoker. His blood pressure is 150/90 mm Hg and pulse is 90/min. Lung and heart examinations are unremarkable. Laboratory studies are normal. An electrocardiogram reveals a left bundle branch block that is unchanged from prior studies. Which of the following is the most appropriate management at this time?
A. Cancellation of surgery
B. Clearance for surgery
C. Preoperative coronary arteriography
D. Stress testing before surgery
E. Start beta-blocker and clear for surgery

A 58-year-old woman with congestive heart failure (CHF) comes to the emergency department with increasing shortness of breath and an 8-lb weight gain over the past week. She states that she ran out of her medications and has been too busy to have her prescriptions refilled. On further questioning, she also admits to having recently given up on her low-salt diet. The shortness of breath is worse with lying down or with exertion, to the point that she has difficulty walking to the bathroom. Aside from these complaints, her review of systems is unremarkable. Her past medical history, apart from congestive heart failure, is significant for diabetes mellitus type 2 and a history of depression. Her medications, when she was taking them, included an ACE inhibitor, a beta-blocker, furosemide, a daily aspirin, a sulfonylurea, NPH insulin, and fluoxetine. Vital signs are: temperature 37.0 C (98.6 F), blood pressure 103/77 mm Hg, pulse 62/min, and respirations 20/min. Chest examination reveals diffuse, fine rales. Cardiac examination reveals a faint third heart sound and a jugular venous pressure of 10-12 cm. The patient has 2+ pitting edema of her lower extremities. An echocardiogram reveals a dilated left ventricle with a reduced ejection fraction of 25-30%. The patient is admitted for a CHF exacerbation and is treated with afterload reduction with an ACE inhibitor, diuresis with furosemide, and inpatient cardiac rehabilitation. By day three, the patientís weight has returned to her previous baseline and orthopnea and dyspnea on exertion have improved modestly. Her medications have been restarted and the importance of medical compliance and dietary restriction is reemphasized. Her outpatient medicine regimen is scrutinized for any additional medications that may be beneficial. Which of the following diuretics would most likely reduce mortality in this patient?
A. Acetazolamide
B. Ethacrynic acid
C. Furosemide
D. Hydrochlorothiazide
E. Spironolactone
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Old 10-22-2011
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C. Preoperative coronary arteriography
E. Spironolactone
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Old 10-22-2011
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C. Preoperative coronary arteriography

E. Spironolactone
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Old 10-23-2011
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Default Answer

The correct answer is E. This patient is at moderate risk for an ischemic event, given his limited functional capacity, hypertension, diabetes, age, and history of left bundle branch block. However, his functional capacity is at least 4 metabolic equivalent by the Duke Criteria. If the surgery were not emergent, further evaluation would have been helpful to delineate his cardiac function. However, since he is not having active ischemia, his cardiac status should be optimized with a beta-blocker, which has been shown to reduce perioperative mortality.
Canceling the surgery (choice A) would not be appropriate, given the patientís presentation and the lack of any absolute contraindication to surgery.
Clearance for surgery (choice B) without optimization with a beta-blocker is not optimal either because the patient does have significant cardiac risk factors.
Coronary arteriography (choice C) can be explored after surgery. It is not an option preoperatively: even if the patient does need stenting, it is not possible to do so because he cannot be placed on anticoagulation after the procedure.
Stress testing (choice D) would not change the patientís management inasmuch as he is not actively ischemic; he will be placed on beta-blockers in any case, and he cannot undergo angioplasty or stenting.

The correct answer is E. Spironolactone, a mineralocorticoid antagonist, is proven to reduce morbidity and mortality in congestive heart failure. Aldosterone was originally thought to be important int he pathophysiology of the heart failure only because of its ability to increase sodium retention and potassium loss. However, in the past several years, research has shown that aldosterone also causes myocardial and vascular fibrosis, direct vascular damage, and baroreceptor dysfunction and prevents the uptake of norepinephrine by myocardium. The reduction in the risk of death does not appear to be due entirely to an effect of spironolactone on sodium retention or potassium loss; instead, it is likely that spironolactone is also cardioprotective. Although the exact cause
of the reduction in the risk of death remains speculative, it is postulated that an aldosterone-receptor blocker can prevent progressive heart failure by averting sodium retention and myocardial fibrosis and preventing sudden death from cardiac causes by averting potassium loss and by increasing the myocardial uptake of norepinephrine. Spironolactone may prevent myocardial fibrosis by blocking the effects of aldosterone on the formation of collagen, which in turn could play in reducing the risk of sudden death from cardiac causes, since myocardial fibrosis could predispose patients to variations in ventricular-conduction times and, hence, to reentry ventricular arrhythmias.
Acetazolamide (choice A) is a weak diuretic that acts by inhibiting luminal carbonic anhydrase in the renal tubules. It is often used to alkalinize the urine, trapping acidic toxins in the urine that would otherwise diffuse back across the luminal membrane. Its role in CHF is limited.
Ethacrynic acid (choice B) is a loop diuretic used instead of furosemide in patients with sulfa allergies.
Furosemide (choice C) is usually the drug of choice in maintaining a balanced fluid status in CHF patients. It has no proven benefit on long-term mortality, however, and does not influence the natural course of the disease.
Thiazide diuretics, such as hydrochlorothiazide (choice D) or metolazone, are sometimes used synergistically with a loop diuretic in patients with severe edema. This combination may reduce symptoms, but is not proven to reduce mortality.
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