[Diagnosis and differential therapy of mitral stenosis].
Clinical symptoms and diagnostic findings in patients with mitral stenosis are usually determined by the extent of the stenosis. Compared to a normal mitral valve area (MVA) of > 4 cm2, MVA in patients with severe mitral stenosis is usually reduced to < 1.5 cm2. In older patients symptoms are frequently influenced by concomitant diseases (e.g. atrial fibrillation, arterial hypertension or lung disease). An important diagnostic element besides anamnesis, auscultation, ECG and chest X-ray is echocardiography, which is required in order to measure non-invasively and reliably the mitral valve gradient (MVG), the MVA and morphologic changes to the valves, as well as concomitant valvular disease, ventricular functions and, where appropriate, left-atrial thrombi. In addition to the surgical treatment of patients with severe mitral stenosis, which has been an established procedure for 50 years, percutaneous balloon mitral valvuloplasty (MVP) has recently established itself as an alternative option. At the current time, the Inoue technique seems to display the most advantages. Following transseptal puncture, the Inoue balloon is guided transvenously into the left atrium and then into the left ventricle using a special support wire. The balloon is short and soft. Its special unfolding character enables it to be placed securely in the mitral valve without any risk of ventricular perforation (Figure 1). As with surgical commissurotomy, balloon valvuloplasty leads to a separation of fused commissures. This results in a significant reduction of MVG, accompanied by an increase in the MVA (Figure 2). The results and success of MVP are influenced by the morphology of the valves and the changes to the subvalvular apparatus. In randomized studies, the results of surgical commissurotomy were comparable with those of balloon mitral valvulotomy. In our hospital, an increase in MVA from 1.0 to 1.8 cm2 could be achieved in 899 patients (mean age 56 +/- 3 years). In younger patients with less significantly changed valves, the results were correspondingly more favorable than in older patients (Figure 3). Provided valve morphology is suitable, a relapse following previous surgical commissurotomy is not a contraindication for MVP. The MVP complication rate is very low in skilled hands: mortality is below 1%; mitral insufficiency occurs in 3 to 10% of interventions; we observed a severe mitral insufficiency in 5% of our patient group. Thromboembolic complications may be prevented after exclusion of atrial thrombi by transesophageal echocardiography. The occurrence of a hemodynamically significant atrial septum defect is a very rare event. The mid-term results (5 to 10 years) and the low restenosis rate following MVP in patients with suitable valves are comparable with those of surgical commissurotomy. In older patients with considerably changed, calcified and fibrotic valves, restenosis may be expected within 1 to 5 years. In these patients MVP represents no more than a palliative intervention in order to prolong the point of surgery, for example in patients where a concomitant aortic valve disease in itself is not yet an indication for surgery. Special indications are to be found in young patients with severe mitral stenosis yet few symptoms, in pregnant females and in emergency situations, as well as in patients with Grade II mitral stenosis with intermittent atrial fibrillation. Catheter therapy is much less invasive than surgery. In case of failure the patient still has the option of surgical therapy. Patients with morphologically significantly altered valves usually receive a valve replacement since an unsuccessful reconstruction would lead to a second operation within a very short time interval. Contraindications for MVP are thrombi in the left atrium, a previously existing > Grade II mitral regurgitation and marked, degenerative destruction of the subvalvular apparatus or extensive calcification of the valves. MVP thus represents a significant addi