05/09/2025
✴️ Don’t use PHT to calculate Mitral valve area in the following situations:
🚨A- Non-rhematic MS:
It is important to emphasize that the 220/PHT formula was developed for rheumatic MS and should not be used for other causes, for example, senile MS related to mitral annular calcification.
🚨B- After percutaneous mitral balloon valvuloplasty [PMBV] or also known as percutaneous mitral commissurotomy [PMC]:
There are abrupt changes in mitral gradient and left atrial compliance within the first 48 hours after balloon mitral commissurotomy. Following PMC, LV diastolic pressure may rise significantly as the relatively noncompliant left ventricle experiences an abrupt increase in transmitral flow after balloon-mediated relief of MS, this will lead to shorter PHT and overestimation of MVA.
🚨C- Acute severe aortic regurgitation:
Aortic regurgitation increases the rate of left ventricular diastolic filling because blood enters the LV from both the mitral valve and the aortic valve. This shortens the P t½. In acute severe aortic regurgitation, the diastolic LV volume and hence the pressure rises rapidly, which in turn rapidly reduces the transmitral gradient.
🚨D- Diastolic dysfunction:
Abnormal LV relaxation prolongs PHT (leading to underestimation of MVA), whereas abnormal LV compliance shortens PHT (leading to overestimation of MVA). Thus, the PHT method should be used with caution in older adult patients with MS.
🚨E- Atrial septal defect:
In patients with both MS and atrial septal defect (referred to as Lutembacher syndrome), a significant left-to-right shunt decompresses the leaf atrium, decreases the transmitral gradient, and shortens the PHT, leading to overestimation of MVA (larger area).
🚨F- Mitral valve prosthesis:
220/PHT formula is not validated for Effective or***ce area calculation in prosthetic valves
