In patients with mitral stenosis the need for therapeutic intervention can be assessed by clinical and non-invasive data. Mitral valve replacement is indicated when marked dyspnoea on mild exertion, dyspnoea at rest or pulmonray oedema, haemoptpis, atrial fibrillation, recurrent systemic emboli or right ventricular failure occur in a patient with a mitral valve area of <1·5cm2, as memured by Doppler echocardiography. This treatment will entail life-long anticoagulation in the majoriv of patients. Closed commissurotomy is no longer considered a valid therapeutic alternative due to its limited success rate but open cormmissurotomy and balloon valvotomy may be performed in patients with no significant calcification of valve cusps and no major concomitant mitral regurgitation. Preservation of the subvalvular apparatus and left ventricular geometry can be comidered the most important advantages of these techniques. More severe chronic symptom are generally required m indication for mitral valve replacement because of the additional long-term imponderabilities imposed by an implanted artrficial device. Therefore, in patienb with mitral stenosis different symptom and clinical findings will eventually lead to different intervention

Burckhardt, D.

Hoffmann, A.

Kiowski, W.

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European Heart Journal (1991) U {Supplement B), 95-98Treatment of mitral stenosisD . BURCKHARDT, A . HOFFMANN AND W . KlOWSKIDivision of Cardiology, University Hospital Basel/SwitzerlandKEY WORDS: Mitral stenosis, commissurotomy.In patients with mitral stenosis the need for therapeutic intervention can be assessed by clinical and non-invasivedata. Mitral valve replacement is indicated when marked dyspnoea on mild exertion, dyspnoea at rest orpulmonary oedema, haemoptysis, atrial fibrillation, recurrent systemic emboli or right ventricular failure occur ina patient with a mitral valve area of <l-5cm2, as measured by Doppler echocardiography. This treatment willentail life-long anticoagulation in the majority of patients.Closed commissurotomy is no longer considered a valid therapeutic alternative due to its limited success rate butopen commissurotomy and balloon valvotomy may be performed in patients with no significant calcification ofvalve cusps and no major concomitant mitral regurgitation. Preservation of the subvalvular apparatus and leftventricular geometry can be considered the most important advantages of these techniques. More severe chronicsymptoms are generally required as indication for mitral valve replacement because of the additional long-termimponderabilities imposed by an implanted artificial device. Therefore, in patients with mitral stenosis differentsymptoms and clinical findings will eventually lead to different interventions.IntroductionSince Bailey's first report of closed commissurotomyin 19491'1 several procedures, such as open commis-surotomy, mitral valve replacement and latelypercutaneous mitral balloon valvotomy have beenadvocated as interventions in patients with significantmitral stenosis. Each procedure has its ownindications and merits which shall be discussed in thisreport.Natural history of mitral stenosisFollowing an episode of rheumatic fever patientswith mitra] stenosis are usually asymptomatic for 10 to20 years. When symptoms first appear about another 5to 10 years will pass until disabling symptomsdevelop121. Once major symptoms are present lifeexpectancy is shortened and 5-year survival is 62% inpatients with NYHA class III symptoms and only 15%with NYHA class IV"'4' (Fig. 1). Furthermore, aone-year mortality rate of close to 50% was reportedby Rapaport"1 in patients with mitral stenosisdeveloping congestive right heart failure. The mostcommon causes of death are pulmonary oedema,pulmonary hypertension with right ventricular failure,systemic embolism and infective endocarditis.Haemodynamic background of symptoms in mitralstenosisWith increasing obstruction of the mitral valve thereis a concomitant rise in left atrial pressure, and inpatients with mitral stenosis a close correlationComspondenct: Dieter Burckhardt, MD, Professor of Cardiology,Division of Cardiology, University Hospital Basel, CH-4031Basel/Switzerland.between mitral valve area and symptomatology can beobserved, although some variability in exercisetolerance in patients with the same degree of stenosisis not an infrequent finding (Table 1). If left atrial andpulmonary capillary pressures exceed 30 mmHg,capillary hydrostatic pressures exceed oncotic press-ures resulting in transudation of plasma into theintrastitial tissue and the intra-alveolar space leading tomarked shortness of breath and pulmonary oedema.This mechanism is accentuated by exercise since atwo-fold increase in mitral flow produces a four-foldincrease in pressure-gradient across the valve.Accordingly, left atrial pressure rises steeply duringexercise. The mechanism preventing pulmonarycapillary pressures rising above pulmonary oedemalevel is reduction in diastolic mitral flow and cardiacoutput. This reduction in flow and cardiac output isaccomplished by an increase in pulmonary vasculartone within the smaller arteriolar branches of thepulmonary circulation leading to active pulmonaryhypertension. The resulting low cardiac output isresponsible for symptoms such as increased fatigueand a marked decrease in exercise tolerance.Furthermore, chronic elevation of pressures within theleft atrium will lead to dilatation and finally to atrialfibrillation. Chronic, permanent atrial fibrillation isgenerally not seen until mitral stenosis is hemodynam-ically significant.Data from the Framingham study1" showed that thecerebrovascular accident rate was increased six-foldwith isolated atrial fibrillation and 18-fold when atrialfibrillation was associated with mitral valve disease.Since most of these cerebro-vascular accidents weredue to embolism, it is not surprising that in 43% ofpatients with significant mitral stenosis and in 8-5% ofpatients with mitral regurgitation left atrial thrombi0195-668X/91/0B0095 + 04 $03.00/0 1991 The European Society of Cardiology96 D. Burckhardt et al.Asymptomatic,latent pertod(10-20 years)RheumaticfeverSymptomaticperiod(5-KD years)MildsymptomsDisablingsymptomsNYHA IHXNYHA m.":5-year :mortality:.' 38% ':-85% . iFigure 1 National history of mitral stenosis.Table 1 Mitral valve area (MVA) and symptomatic status inpatients with mitral stenosisMVA (cm2) Symptoms>2-0 Asymptomatic at rest and during exercise2-0-1 -5 Asymptomatic at rest; shortness of breathduring heavy exercise1-5-1-2 a- or oligo-symptomatic at rest; shortness ofbreath with mild exercise<l-2 Nocturnal cough, PND, orthopnoea,haemoptysis, RV failure.PND, paroxysmal nocturnal dyspnoea, RV = right ventricular.were found during surgery121. Approximately 20% ofpatients with rheumatic mitral valve disease ex-perience systemic embolization at some time duringthe course of the illness and in 25% the embolism isrecurrent"1. Fifty percent of detected emboli appear inthe cerebral circulation.With regard to natural history and haemodynamicsthe following signs and symptoms are of clinicalimportance in patients with mitral stenosis: markedshortness of breath with mild exercise, paroxysmalnocturnal dyspnoea, orthopnoea, history of pulmo-nary oedema, haemoptysis, increased fatigue, markeddecrease in exercise tolerance, systemic embolism,right ventricular failure and atrial fibrillation.Indications for interventions in patients with mitralstenosisSigns and symptoms in which an intervention shouldbe considered in patients with mitral stenosis are listedin the following section with their causes inparentheses. Asymptomatic patients with the clinicalpicture of mitral stenosis should undergo exercisetesting in order to objectively assess their exercisetolerance.(A) SYMPTOMSThese comprise any form of dyspnoea (elevatedpulmonary capillary wedge pressure). More severechronic symptoms are required as indications formitral valve replacement than for percutaneous mitralballoon valvotomy because of the additional long-termimponderabilities imposed by the artificial device.Other symptoms include increased fatigue or markeddecrease in exercise tolerance (low cardiac outputwith pulmonary arteriolar hypertension); haemoptysis(pulmonary venous hypertension).(B) CLINICAL FINDINGSThese comprise systemic embolism (enlargement ofleft atrial appendage, atrial fibrillation); signs of rightventricular failure (pulmonary hypertension); atrialfibrillation (dilatation of left atrium).(C) ECHOCARDIOGRAPHIC FINDINGSThese comprise pressure half time (t/2) > 150 ms,i.e. MVA < 1-5 cm2; mean diastolic pressure gradientat rest >5 mmHg.(D) HAEMODYNAMIC DATAThese comprise mean diastolic pressure gradient atrest >5 mmHg; pulmonary capillary wedge pressure>20mmHg; systolic pulmonary artery pressure>50mmHg; mitral valve area <l-5cm2; pulmonaryarteriolar resistance >3 units.Interventions in patients with significant mitralstenosisThere are four possible interventions in patientswith haemodynamically significant mitral stenosis: (a)closed commissurotomy; (b) open commissurotomy;(c) mitral valve replacement (with mechanical orbioprosthetic valves); (d) percutaneous mitral balloonvalvotomy.Comparative studies from Farhat et al.m haveshown that open commissurotomy improved haem-odynamic values to a greater extent than closedcommissurotomy, both at rest and during exercise.Therefore, in industrial countries closed commissuro-tomy is no longer performed and will not be describedin this report. Each of the remaining three procedureshas its advantages (Table 2) and there is a need forproper patient selection.Mitral stenosis treatment 97Table 2 Advantages and disadvantages of different procedures in mitral stenosisAdvantages DisadvantagesOpen commissurotomy Visualization of valveopening and subvalvularapparatusPreservation of subvalvularapparatusAdditional surgicalprocedures possibleCalcifications and mitralregurgitation are nocontraindicationsAdditional surgicalprocedures possiblePercutaneous mitral balloon Non-surgical interventionvalvotomy Preservation of sub-valvularapparatusMitral valve replacementSurgical interventionMarked calcification andsevere mitral regurgitationare contraindicationsSurgical interventionLife-long anticoagulation(with mechanical devicesand/or atrial fibrillation)ThromboemboliccomplicationsHeavy calcification andmarked mitralregurgitation arecontraindicationsNo visualization of mitralvalve and sub-valvularapparatusAdditional surgicalprocedures not possible(A) PREREQUISITE FOR OPEN COMMISSUROTOMY181These comprise (1) Pliable valves (loud S, andpresence of opening snap); (2) Absent or only slightcalcification of mitral valve (reduced risk ofdislodgement of calcific material); (3) Absent or onlyslight mitral regurgitation; no severe subvalvulardisease (repair of valvular and subvalvular apparatuspossible); (4) No previous commissurotomy; (5)Concomitant other valvular heart disease and/orcoronary artery disease.Left atrial thrombi are no contraindication (reducedrisk of intra-operative embolism).(B) PREREQUISITE FOR MJTRAL VALVE REPLACEMENTThese comprise (1) Marked calcification of valve;(2) Moderate to severe concomitant mitral regurgita-tion; (3) Chronic atrial fibrillation with markeddilatation of left atrium together with atrial thrombi;(4) Significant involvement of the subvalvularapparatus; (5) Concomitant other valvular heartdisease and/or coronary artery disease.(C) PREREQUISITE FOR PERCUTANEOUS MITRALBALLOON VALVOTOMY1"These comprise (1) Pliable valves (loud S, andpresence of opening snap); (2) Absent or minimalcalcification; (3) Absent or mild mitral regurgitation;(4) No thrombi in left atrium and no recent previousthromoembolic events; (5) Absence of other con-comitant valvular heart disease and/or coronary arterydisease.ConclusionsIn patients with mitral stenosis the need fortherapeutic intervention can be assessed by clinicaland non-invasive data. The indication for a givenintervention depends mainly on the status of themitral apparatus, which can best be evaluated bytransoesophageal and transthoracic echocardiography.Closed commissurotomy is no longer considered avalid therapeutic alternative due to its limited successrate but open commisurotomy and balloon valvotomymay be performed in patients without significantcalcification of valve cusps and no major concomitantmitral regurgitation. Preservation of the subvalvularapparatus and left ventricular geometry can beconsidered the most important advantages of thesetechniques. More severe chronic symptoms andcontraindications either to balloon valvotomy orcommissurotomy are generally required as indicationsfor mitral valve replacement because of the additionallong-term imponderabilities imposed by an implantedartificial device. Therefore, in patients with mitralstenosis different symptoms and clinical findings willeventually lead to different interventions.Finally, for certain special indications such asendstage mitral stenosis, severe pulmonary hyperten-sion, major involvement of the subvalvular apparatusor symptomatic mitral stenosis during pregnancy theoptimal type of intervention is still a matter of debate.References[1] Bailey CP. The surgical treatment of mitral stenosis (mitralcommissurotomy). Dis Chest 1949; 15: 377-84.[2] Hell RJC. Rheumatic mitral valve disease. In: Julian DG,Camm AJ, Fox KM, Hall RJC, Diseases of the heart.Poole-Wilson, eds. London: Bailliere Tindall, 1989.[3] Bland EF, Jones TD. Rheumatic fever and rheumatic heartdisease. A 20 year report on 1000 patients followed sincechildhood. Circulation 1951; 4: 836-43.[4] Oleson KH. The natural history of 271 patients with mitralstenosis under medical treatment. Br Heart J 1962; 24:349-57.98 D. Burckhardt et al.[5] Rapaport E. Mitral stenosis. Chapter 38. In: Pannley WW,Chatterjee K., eds. Philadelphia: J. B. Lippincott, 1989.[6] Kannel WB, Abbot RD, Savaje DD « al. Epidemiologicfeatures of chronic atria] fibrillation: The Framinghara study.N Engl J Med 1982; 306: 1018-22.[7] Farhat MB, Boussadia H, Gandjbakhch I et al. Closed vsopen mitral commissurotomy in pure noncalcific mitralstenosis: Haemodynamic studies before and after operation.J Thorac Cardiovasc Surg 1990; 99: 639-44.[8] Kirklin JW and Barratt-Boyes BG. In: Cardiac Surgery.John Wiley & Sons, 1986: 323-73.[9] Vahanian A, Michel PL, Cormier B, Vitoux B, Michel X,Slama M, Sarano LE, Trabelsi S, Ben Ismail M, Acar J.Results of percutaneous mitral commissurotomy in 200patients. Am J Cardiol 1989; 63: 847-52.

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