MOC Questions

SEPTEMBER 11, 2008

Preparing for the American Board of Internal Medicine Maintenance of Certification
The following questions can assist candidates for the Maintenance of Certification Exam in Cardiovascular Disease in preparing for this test. We hope you find this helpful and welcome your feedback.

Questions
1. A 75-year-old white male with extensive triple-vessel disease and reduced ejection fraction is referred for elective coronary artery bypass graft (CABG) surgery. On physical examination, he has a harsh right carotid bruit. A carotid ultrasound reveals an 80% right carotid artery stenosis and a normal left carotid artery. Your recommendation would be to:
a) Proceed with simultaneous CABG and carotid endarterectomy (CEA).
b) Proceed with CABG alone.
c) Proceed with CEA, followed by CABG in 4 weeks.
d) Perform carotid artery stenting, followed by CABG in 4 weeks.

2. A 56-year-old male is admitted with unstable angina and ST segment depression with negative cardiac enzymes. He remains pain-free, and his electrocardiogram changes resolve on intravenous nitroglycerin. He is scheduled for catheterization and percutaneous coronary intervention (PCI) the following day. His fasting blood sugar is 140 mg/dL, and his peak afternoon glucose is 220 mg/dL. He has no history of diabetes mellitus. The best course of management would be:
a) Cover his glucose levels with a sliding scale to keep serum glucose < 200 mg/dL.
b) Do not actively treat his glucose levels, but discontinue any intravenous glucose-containing solutions.
c) Institute an insulin drip to maintain serum glucose between 100 mg/dL and 150 mg/dL and continue the drip during the catheterization and possible PCI.
d) Postpone the catheterization and start oral glycemic agents.
e) Postpone the catheterization and institute subcutaneous insulin therapy until serum glucose returns to normal.

3. A 65-year-old male is scheduled for open repair of a 6-cm abdominal aortic aneurysm. As part of a preoperative evaluation, it is noted that he has a positive exercise stress test. A cardiac catheterization shows a 40% right coronary artery lesion, a 40% left anterior descending artery lesion, and a 50% obtuse marginal coronary artery lesion with well-preserved ejection fraction. He is normotensive and currently taking no medication. The medication(s) that will give him the LEAST protection from an ischemic event during his aneurysm surgery include:
a) Aspirin.
b) Beta-blockers.
c) Statins.
d) Angiotensin-converting enzyme (ACE) inhibitors.
e) Calcium channel blockers.
f) None of the above.
g) All of the above.

4.  A patient is seen in your office after successful valve surgery and is in normal sinus rhythm. Which of the following valve(s) does not routinely require any postoperative anticoagulation?
a) Bioprosthetic valve in the aortic position.
b) Bioprosthetic valve in the mitral position.
c) Bioprosthetic valve in the tricuspid position.
d) Bioprosthetic ring in the mitral position.
e) All of the above.
f) None of the above.

5. True statements regarding the use of the radial artery as a conduit during CABG surgery include:
a) It should not be used in patients with diabetes mellitus.
b) It should not be used to graft a vessel with < 80% stenosis.
c) It should not be used in patients who are intolerant of oral nitrates.
d) It should not be used in patients with a positive Allen’s test.
e) All of the above.
f) A and C.
g) B and D.

6. A 67-year-old male is admitted with a non-ST elevated myocardial infarction and, on catheterization, is found to have extensive 3-vessel disease, and CABG is recommended. He is now pain-free on intravenous nitroglycerin and heparin. Prior to catheterization, he received a loading dose of clopidogrel, followed by 3 days of maintenance therapy. The CABG surgery should be scheduled:
a) 24 hours after catheterization to avoid further ischemia.
b) 48 hours after catheterization to avoid bleeding complications.
c) 5 days after catheterization to avoid bleeding complications.
d) If angina occurs despite optimal medical management, irrespective of when clopidogrel was given.
e) All of the above.
f) C and D.
g) None of the above.

7. The most sensitive renal predictor of postoperative mortality in patients undergoing cardiac surgery is:
a) Serum creatinine.
b) Glomerular filtration rate.
c) Proteinuria.
d) None of the above.

8. A 70-year-old female with chronic stable angina and 3-vessel coronary artery disease is scheduled for elective CABG. She is currently taking 81 mg of aspirin each day. She should be instructed to:
a) Discontinue aspirin 7 days prior to surgery.
b) Discontinue aspirin 2 days prior to surgery.
c) Discontinue aspirin 24 hours prior to surgery.
d) Continue taking aspirin up to the time of surgery.

9. True statements regarding off-pump coronary artery bypass (OPCAB) versus conventional CABG on cardiopulmonary bypass include:
a) OPCAB reduces perioperative mortality.
b) OPCAB significantly reduces blood loss and blood production use.
c) OPCAB results in better presentation of neurocognitive function.
d) All of the above.
e) None of the above.

10. A 65-year-old hypertensive male is admitted with a type III aortic dissection beginning just distal to the left subclavian artery and extending to just above the diaphragm. Following initiation of antihypertensive therapy, he remains pain-free. His management should now include:
a) Medical management with antihypertensive therapy.
b) Surgical replacement of the thoracic aorta.
c) Endovascular repair of the thoracic aorta.


Answers
1: B
Currently, there is no evidence to suggest that a combined CABG plus CEA will decrease the incidence of a perioperative neurological event. Controversy exists regarding the merits of CEA or carotid stenting in asymptomatic patients. Proceeding with a CEA or stenting, followed later by a CABG will increase the incidence of myocardial infarction (MI). Carotid stenting followed by CABG means that clopidogrel (Plavix) will have to be discontinued and the patient placed on intravenous heparin. Bridging to surgery with enoxaparin (Lovenox) increases the incidence of perioperative bleeding during all cardiac surgical procedures.

Lazar HL, Menzoian JO. Coronary artery bypass grafting in patients with cerebrovascular disease. Ann Thorac Surg. 1998;66(3):968-974.

2: C
Nearly 60% of patients admitted with acute coronary syndromes have abnormal glucose metabolism. Approximately 30% to 40% of these patients have known diabetes mellitus. Fifteen to 20 percent have new-onset diabetes mellitus. Poor glycemic control at the time of PCI increases the risk of restenosis, reintervention, and rehospitalization. Patients with diabetes whose glycemic control is optimal have patency rates of target vessels similar to patients without diabetes. An insulin drip targeted to keep serum glucose < 180 mg/dL is the best method of achieving rapid and effective glycemic control.

Cao JJ, Hudson M, Jankowski M, et al. Relation of chronic and acute glycemic control on mortality in acute myocardial infarction with diabetes mellitus. Am J Cardiol. 2005;96(2):183-186.

Conaway DG, O’Keefe JH, Reid KJ, et al. Frequency of undiagnosed diabetes mellitus in patients with acute coronary syndrome. Am J Cardiol. 2005;96(3):363-365.

Corpus RA, George PB, House JA, et al. Optimal glycemic control is associated with a lower rate of target vessel revascularization in treated type II diabetic patients undergoing elective percutaneous coronary intervention. J Am Coll Cardiol. 2004;43(1):8-14.

3: E
Beta blockers and statins will provide the most optimal protection for patients undergoing noncardiac surgery with underlying coronary disease. Aspirin and ACE inhibitors also offer some advantages. Calcium channel blockers are least likely to offer any benefit, especially in the normotensive patient.

Arora R, Sowers JR, Saunders E, et al. Cardioprotective strategies to improve long-term outcomes following coronary artery bypass surgery. J Card Surg. 2006;21(2):198-204.

4: A
The current consensus among surgeons is that all bioprosthetic valves in the mitral or tricuspid position and mitral rings require some form of anticoagulation for 6 weeks to 3 months. This could take the form of warfarin (Coumadin) or aspirin and clopidogrel. Bioprosthetic valves in the aortic position do not by themselves require anticoagulation unless the patient is in atrial fibrillation.

Orszulak TA, Schaff HV, Mullany CJ, et al. Risk of thromboembolism with the aortic Carpentier-Edwards bioprosthesis. Ann Thorac Surg. 1995;59:462-468.

5: G
The radial artery has emerged as another potential arterial conduit during CABG surgery. To obtain optimal patency, it should only be used to bypass vessels with > 80% stenosis and in patients with a negative Allen’s test.

Buxton BF, Raman JS, Ruengsqkulrach P, et al. Radial artery patency and clinical outcomes: 5-year interim results of a randomized trial. J Thoracic Cardiovasc Surg. 2003;125(6):1363-1371.

Tatoulis S, Royse AG, Buxton BF, et al. The radial artery in coronary surgery: a 5-year experience—clinical and angiographic results. Ann Thorac Surg. 2002;73(1):143-147.

6: F
Clopidogrel has been shown to increase morbidity and mortality when given prior to CABG. Recent studies have shown that it should be discontinued for at least 5 days prior to CABG, if possible. However, if recurrent angina is present and CABG must be done sooner, patients should receive platelet transfusions following discontinuation from cardiopulmonary bypass.

Ascione R, Ghosh A, Rogers CA, et al. In-hospital patients exposed to clopidogrel before coronary artery bypass graft surgery. A word of caution. Ann Thorac Surg. 2005;79:1210-1216.

7: B
Glomerular filtration rate (GFR) is an independent predictor of operative mortality following CABG surgery. A GFR < 60 mg/min per 1.73 m2 has been associated with increased perioperative mortality and is a more sensitive indicator than serum creatinine.

Hillis GS, Crual BL, Buchan KG, et al. Renal function and outcome from coronary artery bypass grafting. Circulation. 2006;113:1056-1062.

Cooper WA, O’Brien JM, Thourani VH, et al. Impact of renal dysfunction on outcomes of coronary artery bypass surgery. Circulation. 2006;113:1063-1070.

8: D
Aspirin should be taken right up to the time of CABG, because it has been shown to decrease cardiac ischemic events and reduce postoperative mortality, especially in those patients with acute coronary syndromes and recent MIs.

Bybee KA, Powell BD, Valeta U, et al. Preoperative aspirin therapy is associated with improved postoperative outcomes in patients undergoing coronary artery bypass grafting. Circulation. 2005; 112(9 suppl):I286-I292.

Ferraris VA, Ferraris SP, Moliterno DJ, et al. The Society of Thoracic Surgeons Practice Guideline Series: Aspirin and Other Antiplatelet Agents During Operative Coronary Revascularization. Ann Thorac Surg. 2005;79:1454-1461.

9: E
Despite the initial enthusiasm for OPCAB surgery, it remains a technique used for coronary revascularization in only 5% to 10% of patients nationwide. Prospective, randomized studies have not shown any benefit for mortality, bleeding, or neurocognitive function. Studies have shown that OPCAB patients receive fewer grafts and have lower patency rates.

Khan NE, DeSouza A, Mister R, et al. A randomized comparison of off-pump and on-pump multi-vessel coronary artery bypass surgery. N Engl J Med. 2004;350(1):21-28.

Selke FW, Di Maso JM, Caplan LR, et al. Comparing on-pump and off-pump coronary artery bypass grafting: numerous studies but few conclusions. Circulation. 2005;111:2858-2864.

10: A
Medical management remains the treatment of choice for uncomplicated, stable patients following a type III aortic dissection. This should consist of beta blockers and therapeutic agents designed to keep systolic blood pressure less than 130 mm Hg. Indications for surgical repair include aneurysmal formation, visceral organ ischemia, and evidence of rupture.

Suzuki T, Mehta RH, Ince H, et al. Clinical profiles and outcomes of acute type B aortic dissection in the current era: lessons from the International Registry of Aortic Dissection (IRAD). Circulation. 2003;108(suppl 1):II312-II317.



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