CHAPTER 15: PROSTHETIC VALVES
Select the single MOST LIKELY answer for the following questions.
1. Which of the following views is optimal for quantifying a paravalvular leak in an aortic valve prosthesis?
a. Midesophageal aortic valve long axis
b. Midesophageal aortic valve short axis
c. Deep transgastric short axis
d. Transgastric two-chamber
e. Midesophageal four-chamber
b. The midesophageal aortic valve view allows quantification of a paravalvular leak in terms of percentage of valve ring circumference occupied by the leak.
2. The constant of 220 ms with the pressure half-time method of valve area calculation can overestimate the effective orifice area of a mitral prosthetic valve.
a. The constant of 220 ms was derived from native stenotic mitral valves. Use of this constant can overestimate the effective orifice area of a prosthetic valve.
3. During placement of a stentless biological valve in the aortic position, a dilated sinotubular junction can lead to which of the following?
a. Distorted valve geometry
a. Proper leaflet coaptation in a stentless valve requires the prosthesis to maintain its engineered shape. A dilated sinotubular junction can cause the cylindrical shape of the valve to be distorted at the distal end, resulting in failure of apposition of the leaflets during diastole. It is the ascending aorta rather than the STJ that is assessed for post-stenotic dilation.
4. The primary advantage of tissue valves is:
c. No need for long-term anticoagulation
c. The major advantage of tissue valves is that they usually do not require long-term anticoagulation. If the patient is already on anticoagulants for some other reason, such as a history of thrombosis or embolism, persistent atrial fibrillation, or a significantly increased left atrial size, surgeons and cardiologists often recommend the use of a mechanical valve because the major advantage of the tissue valve is nullified.
5. The annual rate of thromboembolism (% per patient year) with bioprosthetic valves is: