TABLE 1.

Comparison of cardiac catheterization and Doppler echocardiography for AS evaluation.

Modality	Direct measurements	Advantages	Pitfalls
Cardiac catheterization	Mean transaortic pressure drop (ΔPmean) Maximum instantaneous transaortic pressure drop (ΔPpeak) Peak-to-peak transaortic pressure drop (ΔPP–P) Cardiac Output	Direct pressure measurement	Invasive Radiation exposure Potential risk of embolic stroke Unknown exact anatomic point where full pressure recovery occurs
Doppler echocardiography	Instantaneous VC velocity Peak VC velocity (Vmax) Instantaneous transaortic pressure drop (through modified Bernoulli equation) Mean transvalvular pressure drop (Doppler ΔPmean)	Noninvasive Anatomic Evaluation Widely accessible	Requires good imaging window Does not provide pressure directly LVOT measurement may decrease AVA calculation accuracy Assumption of a single peak velocity value in Bernoulli equation may overestimate the pressure drop

AS indicates aortic stenosis; AVA, aortic valve area; LVOT, left ventricular outflow tract; VC, vena contracta.