Does chronic mitral regurgitation influence Doppler pressure half-time–derived calculation of the mitral valve area in patients with mitral stenosis?

Background In patients with mitral stenosis (MS), Doppler pressure half-time (PHT) may be influenced by hemodynamic variables other than the anatomic mitral valve orifice narrowing. This study was undertaken to assess whether the presence of concomitant mitral regurgitation (MR) affects mitral valve area (MVA) estimation by PHT. Methods Consecutive patients (n = 166) with noncalcific MS, in sinus rhythm, were studied. Group 1 (n = 106) had no or mild MR, and group 2 (n = 60) had moderate or severe MR. MVA was assessed by using the PHT method and planimetry. Results There was a strong correlation between planimetry and PHT MVA in both groups (group 1: r = 0.86, P < .001; group 2: r = 0.73, P < .001). However, compared with planimetry MVA, PHT underestimated MVA by ≥20% in 18 patients (17%) in group 1 and 21 patients (35%) in group 2 (P < .01). Overestimation by ≥20% occurred in 12 patients (11%) in group 1 and in 7 (12%) in group 2. Group 2 subanalysis (group 2A: moderate MR, N = 16; group 2B: severe MR, N = 44) revealed that linear regression weakened with increasing severity of MR (group 2A: r = 0.824, P < .001, group 2B: r = 0.70, P < .001). PHT underestimation of MVA occurred in 31% and 36% of patients in Groups IIA and IIB, respectively (P = NS). Conclusions PHT appears to be reliable for estimating MVA in most patients with MS, even in the presence of MR. However, the presence of significant MR reduces the reliability of PHT-derived MVA, with underestimation of MVA in a significant number of subjects. The severity of MR has a direct impact on PHT-derived MVA.