What is the most common reason for a patient who has undergone closed mitral valvotomy needing a mitral valve replacement later?
Mitral restenosis with calcification is the common reason for requiring mitral valve replacement later. Other possibilities are inadequate valvotomy and development of progressive mitral regurgitation, which could have developed during the procedure or later on due to recurrence of rheumatic activity.
How will you identify mitral restenosis and differentiate it from inadequate valvotomy?
Historically there should have been a sustained improvement of at least 2 classes of NYHA for at least 6 months after the mitral valvotomy. Earlier recurrence of symptoms could be due to an inadequate valvotomy. An initial transient improvement is not enough to qualify for a successful valvotomy as even a slight increase in mitral valve area will produce subjective improvement in a patient with critical mitral stenosis and pulmonary congestion. To diagnose mitral restenosis, there should be at least 50% loss of the initial valve area and the absolute valve area should be below 1.5 sq cm. That would be mean that a diagnosis of mild mitral restenosis will not be tenable – mild mitral stenosis being defined as mitral valve area between 1.5 – 2.0 sq cm. Moderate mitral stenosis is defined as mitral valve area between 1.0 to 1.5 sq. cm. Mitral valve area below 1.0 sq cm constitutes critical or severe mitral stenosis. This is the level of obstruction needed to raise the transmitral gradient above 20 mm Hg and left atrial pressure to 25 mm Hg, the threshold for pulmonary edema.
What is chronic rheumatic carditis?
Rheumatic carditis lasting more than 6 months is considered as chronic rheumatic carditis. Evidence of recent streptococcal infection as an essential criteria for the diagnosis of rheumatic carditis cannot be applied in this situation.
What is patient prosthesis mismatch in aortic valve replacement?
An effective orifice area less than 0.7 sq cm per sq m body surface area for the aortic valve is taken as patient prosthesis mismatch in case of aortic valve replacement.