Critical Care Medicine-Neurologic Disorders>>>>>Mechanical Circulatory Support and the Transplanted Heart
Question 1#

A 60-year-old male with a history of nonischemic dilated cardiomyopathy is admitted to the intensive care unit (ICU) after presenting to the emergency department with several days of progressive dyspnea and lower-extremity swelling. He is found to be hypotensive and tachycardic and on examination is noted to be confused with edematous, cool extremities. A 12-lead ECG shows rapid atrial fibrillation with nonspecific ST-segment changes. His last transthoracic echocardiogram performed 1 year ago showed a severely dilated LV cavity with a left ventricular ejection fraction of 28%, severe mitral regurgitation, moderate aortic insufficiency, and severe tricuspid regurgitation.

In this patient, which of the following represents a contraindication to the use of an intra-aortic balloon pump (IABP)?

 

A. Atrial fibrillation
B. Severe LV cavity dilatation
C. Moderate aortic insufficiency
D. Severe mitral regurgitation
E. Severe tricuspid regurgitation

Correct Answer is C

Comment:

Correct Answer: C

IABP counterpulsation is a commonly used form of mechanical circulatory support that involves placement of a catheter with a heliumfilled balloon into the proximal descending aorta via the common femoral artery under fluoroscopic guidance. The balloon is inflated just after the aortic valve closes and deflates before the opening of aortic valve. This results in blood displacement toward the proximal aorta during diastole while the balloon is inflated, and a suction effect in the aorta during systole when the balloon is rapidly deflated. The resulting hemodynamic changes include a reduction in systolic blood pressure (to reduce myocardial wall stress and work), an increase in diastolic blood pressure, and an increase in the mean arterial pressure. Some studies have shown that IABP counterpulsation results in an increase in total coronary blood flow. 

Contraindications to the use of IABP counterpulsation include severe peripheral arterial disease, aortic dissection or significant aortic aneurysm, and severe coagulopathy. IABP is contraindicated in moderate or greater aortic insufficiency, as inflation of the balloon during diastole will increase regurgitant flow across the aortic valve and worsen heart failure. Atrial fibrillation is not a contraindication to using IABP. IABP counterpulsation decreases preload and thus is beneficial in LV dilation, mitral regurgitation, and tricuspid regurgitation. 

Reference:

  1. Santa-Cruz RA, Cohen MG, Ohman EM. Aortic counterpulsation: a review of the hemodynamic effects and indications for use. Catheter Cardiovasc Interv. 2006;67:68.