Key result
Cardiac-gated 64-section CT accurately measured aortic valve area compared to TTE (1.2 vs 1.1 cm2; r=0.93; P<0.001) and demonstrated morphologic abnormalities in dysfunctional bioprostheses.
Why the study?
Does 64-section multidetector CT accurately measure aortic valve area and assess leaflet morphology compared to TTE in patients with bioprosthetic aortic valve replacement?
Observational (n=54)
Blinded observers
Does 64-section multidetector CT accurately measure aortic valve area and assess leaflet morphology compared to TTE in patients with bioprosthetic aortic valve replacement?
Effect estimate: r = 0.93
Absolute Event Rate: 1.2% vs 1.1%
p-value: p=< .001
64-section multidetector CT provides accurate measurements of aortic valve area that correlate highly with TTE, while also identifying morphologic abnormalities underlying bioprosthetic valve dysfunction.
PURPOSE: To prospectively determine whether cardiac-gated multidetector computed tomography (CT) allows visualization of aortic valve leaflets after bioprosthetic aortic valve replacement (AVR), to provide an accurate method for measuring the aortic valve opening, and to provide morphologic and functional information regarding the mechanism underlying poor function of the bioprosthetic valve. MATERIALS AND METHODS: The institutional review board approved the study protocol; informed consent was given. Fifty-four patients (27 men; mean age, 75 years + or - 8 [standard deviation]) with bioprosthetic AVR implanted 2 years + or - 3 earlier underwent 64-section CT and transthoracic echocardiography (TTE). Two blinded observers manually planimetered the aortic valve area (AVA) by using a computer workstation on end-systolic short-axis CT images and measured opening angles (OAs) between the bioprosthesis annulus base and the free margin on long-axis images. These measurements were compared with those of the effective orifice area (EOA) of the valve at Doppler continuity-equation TTE by using regression and Bland-Altman methods. Morphology and mobility of leaflets in normally functioning (EOA indexed to body surface area [EOA(i)] > 0.65 cm(2)/m(2)) and dysfunctional (EOA(i)< 0.65 cm(2)/m(2)) AVRs were compared. RESULTS: AVA at CT correlated highly to EOA at TTE (r = 0.93, P < .001) but was significantly larger (1.2 cm(2) + or - 0.4 vs 1.1 cm(2) + or - 0.3, P < .001) than EOA at TTE. In dysfunctional bioprostheses (n = 34), CT results showed a variety of morphologic abnormalities, such as leaflet thickening (n = 9), presumed thrombotic material (n = 6), and leaflet calcification (n = 1). Multidetector CT results demonstrated restriction of leaflet motion indicated by lower OA (64 degrees + or - 5 vs 79 degrees + or - 3, P < .0001) in dysfunctional AVRs than in normally functioning AVRs (n = 11). CONCLUSION: Sixty-four-section CT can help accurately measure AVA in bioprosthetic AVR compared with EOA at TTE. It can also show morphologic abnormalities and reduced leaflet motion in a dysfunctional bioprosthesis, thereby potentially unraveling the mechanism of dysfunction.
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Chenot et al. (2009) conducted an observational in Bioprosthetic aortic valve replacement (n=54). 64-section multidetector computed tomography (CT) vs. Transthoracic echocardiography (TTE) was evaluated on Aortic valve area (AVA) at CT compared to effective orifice area (EOA) at TTE (r = 0.93, p=< .001). Cardiac-gated 64-section CT accurately measured aortic valve area compared to TTE (1.2 vs 1.1 cm2; r=0.93; P<0.001) and demonstrated morphologic abnormalities in dysfunctional bioprostheses.
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