Ventricular stroke work loss: validation of a method of quantifying the severity of aortic stenosis and derivation of an orifice formula

Cardiac Department, Kings College Hospital, London, England.

Because aortic stenosis results in the loss of left ventricular stroke work (due to resistance to flow through the valve and turbulence in the aorta), the percentage of stroke work that is lost may reflect the severity of stenosis. This index can be calculated from pressure data alone. The relation between percent stroke work loss and anatomic aortic valve orifice area (measured by planimetry from videotape) was investigated in a pulsatile flow model. Thirteen valves were studied (nine human aortic valves obtained at necropsy and four bioprosthetic valves) at stroke volumes of 40 to 100 ml, giving 57 data points. Valve area ranged from 0.3 to 2.8 cm2 and mean systolic pressure gradient from 3 to 84 mm Hg. Percent stroke work loss, calculated as mean systolic pressure gradient divided by mean ventricular systolic pressure x 100%, ranged from 7 to 68%. It was closely related to anatomic orifice area with an inverse exponential relation and was not significantly related to flow (r = -0.15). An orifice formula was derived that predicted anatomic orifice area with a 95% confidence interval of +/- 0.5 cm2 (orifice area [cm2] = 4.82 [2.39 x log percent stroke work loss], r = -0.94, SEE = 0.029). These results support the clinical use of percent stroke work loss as an easily obtained index of the severity of aortic stenosis.

This article has been cited by other articles:

				S. H. Rahimtoola Determining That Aortic Valve Stenosis Is Severe: Back-to-the-Future: Physical Examination and Aortic Valve Area Index/Energy Loss Index <=0.6 cm2/m2 J. Am. Coll. Cardiol. Img., June 1, 2010; 3(6): 563 - 566. [Full Text] [PDF]

				H. Turto, J. Lommi, M. Ventila, and M. Kupari Doppler echocardiography markedly underestimates left ventricular stroke work loss in severe aortic valve stenosis Eur Heart J Cardiovasc Imaging, October 1, 2007; 8(5): 341 - 345. [Abstract] [Full Text] [PDF]

				S. H Little, K.-L. Chan, and I. G Burwash Impact of blood pressure on the Doppler echocardiographic assessment of severity of aortic stenosis Heart, July 1, 2007; 93(7): 848 - 855. [Abstract] [Full Text] [PDF]

				P. Das, H. Rimington, N. Smeeton, and J. Chambers Determinants of symptoms and exercise capacity in aortic stenosis: a comparison of resting haemodynamics and valve compliance during dobutamine stress Eur. Heart J., July 1, 2003; 24(13): 1254 - 1263. [Abstract] [Full Text] [PDF]

				F. Antonini-Canterin, G. Huang, E. Cervesato, P. Faggiano, D. Pavan, R. Piazza, and G. L. Nicolosi Symptomatic Aortic Stenosis: Does Systemic Hypertension Play an Additional Role? Hypertension, June 1, 2003; 41(6): 1268 - 1272. [Abstract] [Full Text] [PDF]

				J. Bermejo, R. Odreman, J. Feijoo, M. M. Moreno, P. Gomez-Moreno, and M. A. Garcia-Fernandez Clinical efficacy of Doppler-echocardiographic indices of aortic valve stenosis:a comparative test-based analysis of outcome J. Am. Coll. Cardiol., January 1, 2003; 41(1): 142 - 151. [Abstract] [Full Text] [PDF]

				P. E. Gray and A. C. Perrino Jr. Hemodynamic-Induced Changes in Aortic Valve Area: Implications for Doppler Cardiac Output Determinations Anesth. Analg., March 1, 2001; 92(3): 584 - 589. [Abstract] [Full Text] [PDF]

				D. Garcia, P. Pibarot, J. G. Dumesnil, F. Sakr, and L.-G. Durand Assessment of Aortic Valve Stenosis Severity : A New Index Based on the Energy Loss Concept Circulation, February 22, 2000; 101(7): 765 - 771. [Abstract] [Full Text] [PDF]

				T.-M. Lee, S.-F. Su, M.-F. Chen, C.-S. Liau, and Y.-T. Lee Percutaneous Transvenous Mitral Balloon Valvuloplasty Alone in Patients with Combined Aortic and Mitral Stenosis Angiology, May 1, 1997; 48(5): 445 - 450. [Abstract] [PDF]

				W. Voelker, H. Reul, G. N. Ing, T. S. Ing, B. S. Ing, A. S. Ing, and K. R. Karsch Comparison of Valvular Resistance, Stroke Work Loss, and Gorlin Valve Area for Quantification of Aortic Stenosis : An In Vitro Study in a Pulsatile Aortic Flow Model Circulation, February 15, 1995; 91(4): 1196 - 1204. [Abstract] [Full Text]