Cardiovascular Board Review

An elderly woman with shortness of breath

Author and Disclosure Information

 

References

CASE CONTINUED: TRANSESOPHAGEAL ECHOCARDIOGRAPHY

Figure 2. Transesophageal echocardiogram showing thickening and calcification of the mitral valve and subvalvular structures (red arrow) with restricted valve opening in diastole. The left atrium (LA) is dilated. The right atrium (RA) and right ventricle (RV) are also enlarged, suggesting long-standing pulmonary hypertension.

Figure 3. Transesophageal echocardiogram; continuous-wave Doppler recording across the mitral valve showing a mean pressure gradient of 20 mm Hg between the left atrium and left ventricle. A representative velocity time integral (VTI) was chosen (outlined in white dotted line in lower part of the trace) to calculate the gradient; however, since this patient was in atrial fibrillation at that time, an average of several VTIs would be needed to accurately assess the mean pressure gradient across the mitral valve.

Transesophageal echocardiography is performed (Figures 2 and 3) and shows severe mitral stenosis, with a mean pressure gradient of 20 mm Hg and eccentric moderate mitral regurgitation. The mitral leaflets are thickened and calcified, with decreased mobility and subvalvular thickening, findings consistent with rheumatic heart disease. The left atrium is moderately dilated; no thrombus is seen. The right ventricle is severely dilated with moderately to severely decreased function. The calculated mitral valve area is 0.8 cm2, consistent with severe mitral stenosis.

WHAT IS THE TREATMENT?

4. Which of the following is the preferred technique for correcting mitral stenosis in this patient?

  • Percutaneous balloon mitral valvuloplasty
  • Mitral valve surgery
  • Percutaneous mitral valve replacement

Figure 4. Illustration of a normal mitral valve (left) and a rheumatic mitral valve (right). The rheumatic mitral valve is characterized by leaflet thickening, leaflet calcification, and fusion of the commissures. Subvalvular thickening (not pictured) may also occur. These pathologic changes in the mitral valve can result in decreased leaflet mobility and hemodynamically significant mitral stenosis.

Rheumatic carditis can cause thickening and calcification of the mitral valve leaflets and chordae as well as fusion of the mitral commissures. Figure 4 shows a normal mitral valve and a rheumatic mitral valve.

Although there are several options for mechanical treatment of mitral stenosis, percutaneous balloon mitral valvuloplasty by experienced operators is the procedure of choice for patients who have symptomatic moderate-to-severe mitral stenosis with favorable valve morphology but do not have significant mitral regurgitation or left atrial thrombus.3 The hemodynamic and symptomatic improvement that can be expected after this procedure can be predicted using several echocardiographic criteria, including valve mobility, subvalvular thickening, valve leaflet thickening, and valve leaflet calcification,5 as well as the degree of commissural calcification or commissural fusion.6 Success rates are better if the valve is relatively more mobile and has lesser degrees of valvular and subvalvular thickening, calcification, and commissural fusion.

Mitral valve surgery (repair if possible) is indicated in patients with acceptable operative risk who have symptomatic (New York Heart Association class III or IV) moderate-to-severe mitral stenosis if percutaneous balloon mitral valvuloplasty is unavailable, in cases in which an atrial thrombus or moderate-to-severe mitral regurgitation precludes balloon valvuloplasty, or when the valve morphology is not favorable for balloon valvulo-plasty.3

Although she has moderate mitral regurgitation and poor valve morphology, our patient is a poor surgical candidate because of her advanced age, severe pulmonary hypertension, and poor functional status. Patients with moderate-to-severe mitral stenosis and class III or IV symptoms who have nonpliable, calcified valves but are not candidates for open heart surgery have a class IIb indication for percutaneous balloon mitral valvuloplasty—ie, the procedure may be considered.3

In addition, the procedure also carries a class IIb recommendation in patients with moderate-to-severe mitral stenosis and new-onset atrial fibrillation (provided that they do not have a thrombus in the left atrium or moderate-to-severe mitral regurgitation), even without symptoms.3

Percutaneous mitral valve replacement is not available in clinical practice, although this is an active area of clinical research and may be available in the future.

CASE CONTINUED: THE PATIENT UNDERGOES BALLOON VALVULOPLASTY

Figure 5. Fluoroscopic image of the heart in the right anterior oblique view with Inoue balloon inflated across the mitral valve (red arrow). The balloon is inserted into the left atrium via a transseptal atrial puncture.

Percutaneous balloon mitral valvuloplasty is performed (Figure 5). The mean transvalvular gradient is reduced from 20 mm Hg to 8 mm Hg, and the calculated mitral valve area increases from 0.6 cm2 to 1.0 cm2. There are no complications during or after the procedure, and the patient goes home the following day.

Transthoracic echocardiography performed 4 months later shows moderate mitral stenosis with a mean gradient of 9.0 mm Hg, a mitral valve area of 1.7 cm2, and moderate mitral regurgitation. Her right ventricular systolic pressure is estimated to be 74 mm Hg. The patient reports less dyspnea during her housework and now has New York Heart Association class II symptoms. Her treatment regimen includes warfarin (Coumadin) for atrial fibrillation, a beta-blocker to control her heart rate in atrial fibrillation and increase her left ventricular filling time, and a low-dose diuretic.

Next Article: