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2D planimetry is the most commonly used measurement to assess stenosis severity, but 3D TTE and TOE have additional diagnostic value.649 An MVA of ≤1.5 cm2 in conjunction with clinical factors (symptoms, high risk of thromboembolism, or haemodynamic decompensation) is indicative of clinically severe MS. Mean transvalvular gradient and pulmonary pressures reflect its consequences and have prognostic value.649,650 Leaflet thickening and fibrosis, along with commissural fusion and shortening of the subvalvular apparatus, are the most important pathomechanisms of stenosis associated with RHD. The presence and extent of leaflet and subvalvular calcifications influence treatment decisions. Scoring systems have been developed to assess the suitability of patients for percutaneous mitral commissurotomy (PMC) (see Supplementary data online, Table S3).651–653 Exercise testing is indicated in asymptomatic patients or patients with symptoms that are equivocal or discordant with the severity of stenosis. Exercise echocardiography provides additional information on exercise capacity and related changes in mitral gradient and pulmonary artery pressure, and is preferred over DSE, especially when there are contraindications to dobutamine.654 Transoesophageal echocardiography should be systematically performed in PMC candidates to exclude LA thrombus or after an embolic episode, and may play an essential role for procedural guidance.52,655

10.2.2 Medical therapy

Diuretics, beta-blockers, digoxin, non-dihydropyridine calcium channel blockers, and ivabradine can improve symptoms by controlling volume overload and heart rate. Anticoagulation with a VKA with a target international normalized ratio (INR) between 2 and 3 is indicated in patients with AF, and DOACs should be avoided in patients with an MVA of ≤2.0 cm2 according to current evidence.165,656,657 Interventions to restore sinus rhythm (cardioversion or catheter pulmonary vein isolation) are unlikely to be successful in patients with untreated severe MS. If AF is of recent onset and the LA moderately enlarged, cardioversion can be attempted soon after successful intervention or in patients with moderate MS combined with amiodarone treatment.658,659 In patients in sinus rhythm, OAC is indicated after systemic embolism or if a thrombus is present in the LA, and should also be considered when TOE shows dense spontaneous echocardiographic contrast or an enlarged LA (M-mode diameter >50 mm or LA volume >60 mL/m2).660 Prophylaxis of infective endocarditis is indicated as appropriate.5

10.2.3 Indications for intervention

The type (PMC or surgery) and timing of treatment should be decided based on clinical characteristics, the anatomy of the valve and subvalvular apparatus, and local expertise.661–663 The management of clinically severe rheumatic MS is summarized in Figure 14 and Recommendation Table 8. In general, indication for intervention should be limited to patients with clinically severe rheumatic MS (MVA <1.5 cm2) in whom PMC is expected to have a significant impact on clinical outcome. In higherincome countries, where the incidence of rheumatic fever and the number of PMCs performed is low, this treatment should be restricted to expert operators in specialized centres to improve safety and procedural success rate.661,664 Efforts should be made to increase the availability of PMC in lower-income countries, where access to treatment is limited for economic reasons.665,666 Percutaneous mitral commissurotomy may be also considered in symptomatic patients with an MVA of >1.5 cm2, if symptoms cannot be explained by another cause and if the anatomy is favourable (see Table 8). Percutaneous mitral commissurotomy should be considered as a first-line treatment for patients with anatomically suitable rheumatic MS and mild-to-moderate calcification without severe subvalvular impairment. Selected patients with unfavourable anatomical and clinical characteristics can still benefit from PMC, particularly if they are at increased surgical risk. When symptomatic restenosis occurs after surgical commissurotomy or PMC, reintervention in most cases requires surgical valve replacement, but redo PMC can be proposed in selected candidates with favourable characteristics, if the predominant mechanism is commissural refusion. Long-term follow-up has shown favourable results following PMC despite a growing number of elderly patients with suboptimal clinical and anatomical characteristics.663–665

For patients in whom PMC is contraindicated (Table 8), surgical MV repair or, more frequently, replacement are good alternatives. Although repair is much more challenging than for PMR, it can be attempted at experienced centres.663 For patients with multiple VHD including MS, a comprehensive evaluation by the Heart Team and an individualized approach is necessary. Surgery is preferable to PMC in patients with severe MS and severe AV disease, unless the surgical risk is high. In selected cases with severe MS and moderate AV disease, PMC can be performed to postpone surgical treatment of both valves. In high-risk cases with concomitant severe TR, PMC may be considered in selected patients with sinus rhythm, moderate atrial enlargement, and secondary TR due to post-capillary PH. In non-high-risk cases, surgery on both valves is preferred.651,652,662,667 Treatment of patients with low-gradient severe MS (MVA <1.5 cm2, mean gradient <10 mmHg) is challenging, because these patients are often older and have unfavourable anatomy.668,669

10.2.4 Follow-up

Asymptomatic patients with clinically severe MS who have not undergone intervention should be followed up yearly by TTE, and at longer intervals (2–3 years) in cases of moderate stenosis. After PMC, the post-procedural MVA and mean mitral gradient are important parameters that influence long-term clinical outcomes. Follow-up of patients after successful PMC is necessary because asymptomatic restenosis may occur. Progressive rheumatic involvement of other valves should be periodically assessed, irrespective of the therapy modality. Finally, education and the engagement of the family is key in patients with rheumatic MS, since it usually affects young individuals and women of childbearing age.

10.3 Degenerative mitral stenosis with

mitral annular calcification Patients presenting with MAC are elderly and have significant comorbidities, including disease of other valves. Mitral annular calcification is also an indicator of cardiovascular disease severity and is associated with an increased risk of AF, stroke, and death.670,671 The incidence of MAC varies substantially, depending on the age of the studied population and the imaging modality used. It can be a consequence of many different pathological processes and, depending on the underlying disease, can be accompanied by stenosis, regurgitation, or both. However, most patients with MAC do not have significant valvular dysfunction.647,672 Generally, MS occurs due to calcific extension into the MV leaflets or subvalvular apparatus, and in some patients it is associated with combined MR.673 Treatment options (including transcatheter and surgical approaches) are high-risk procedures and evidence from RCTs is lacking. Downloaded from academic.oup.com/eurheartj/article/46/44/4635/8234488 by guest on 07 October 2026