An orifice formula independent of mitral pressure gradient for the evaluation of prosthetic mitral valve obstruction
Seitz, W.S.; Hosenpud, J.D.; Schutz, R.
European Heart Journal 5(11): 932-940
1984
ISSN/ISBN: 0195-668X PMID: 6529943 Document Number: 230776
We have studied an hydraulic orifice equation capable of quantifying the obstructive properties of mitral prostheses from data of a potentially less invasive nature than is required by conventional methods. The results indicate that effective prosthetic orifice area may be computed by the pressure independent equation A = 21SV/DFP2, where A is the effective prosthesis orifice area in cm2, SV is the stroke volume in ml and DFP is the diastolic filling period in s min-1. Areas computed with the pressure independent equation correlate with the results of the modified Gorlin formula (given in the appendix) at a level of r = 0.91 for a series of 17 cases within a range of effective valve areas of 0.50 cm2 to 1.60 cm2. These results suggest that simplified nontraumatic procedures may be developed to screen and follow patients with prosthetic valve implants.