二尖瓣的病理生理学教学课件.ppt

1、 Alan Sihoe Cardiothoracic Surgery Teaching Round 2nd August 20022021/01/211Epidemiology 1998 in the UK:6471 first time valve replacements of which 28%MVR Numbers increasing2021/01/212 Mitral Annulus:fibro-muscular skeleton Anchors base of valve leaflets Leaflets:conn tissue+muscle+vessels/nerves An

2、terior(aortic):larger;1/3 of annulus Posterior(mural):2/3 of annulusAnatomy2021/01/213Anatomy Papillary muscles:Anterolateral Posteromedial Chordae tendinae 1st,2nd,3rd order Approx 25 major chordal trunks 100 attachments to leaflets No consensus on timing of muscle activity with cardiac cycle2021/0

3、1/214Annular dynamics Annular size Increases in late systole(maximum in diastole)Contracts in pre-systole(minimum in midsystole)Annular shape More eccentric in systole Annular position Moves up towards LA in diastole Moves down towards LV apex in systole2021/01/215Leaflet dynamics Opening Starts in

4、center,moving to edges Flapping of edges at max.opening Closing(begins in late diastole)Bulging at base/annular attachment Leaflet ascends towards LA Bulging rolls from annulus to edge2021/01/216 Aetiology:Rheumatic Male:female ratio is 1:2-3 Acquired early(30mmHg:pulm transudation reduced lung comp

5、liance Pulm art systolic pressure 60mmHg impedes RV emptying right heart failure Ultimately irreversible pulm vascular changes2021/01/2111MS:Natural historyProgressive life-long diseaseLong latencySymptoms:i.Low cardiac output:dyspnoea,fatigueii.Pulmonary congestion/HT(orthopnea,PND)right heart fail

6、ure hemoptysisiii.Atrial fibrillation/Thromboembolismiv.Cardiac cachexia2021/01/2112MS:Natural history Onset of symptoms to disability:10 years 10 year survival:Asymptomatic(NYHA class I)80%(progression)Symptomatic(NYHA class III)20%Causes of death:CHF 60-70%Systemic embolism 20-30%Pulmonary embolis

7、m 10%Infection 1-5%2021/01/2113MS:Investigations CXR:LA enlargement,pulm congestion ECG:LA enlargement(notched P in II,V1)atrial arrhythmias?RVH Echo:valve area,LA/LV dimensions Doppler:measures pressure gradients TOE:better mitral/LA visualization Cardiac catheter:not essential Assocd disease;LV ve

8、ntriculography&pressures2021/01/2114MS:Medical therapy Pharmacological Tx of mild heart failure,bronchitis,arrhythmias,hemoptysis Endocarditis prophylaxis Anticoagulation:Hx of AF/thromboembolism Balloon(or open)Valvuloplasty2021/01/2115MS:Indications for surgerySymptomatic(NYHA class III-IV):MVR1.h

9、 long-term survival10 year survival:0-20%90%(89%at 15 yrs)2.h functional capacityValve area 1-1.5cm2 (normal 4-6 cm2)Systemic emboli2021/01/2116MS:Indications for surgery Class I-II:controversial Risk of SCD if asymptomatic:negligible Survival not improved by MVR?role of valvotomy(pulmonary HT,AF)MV

10、R indicated when:Valve area NYHA class II+2021/01/2117Aetiology more diverse than MSMyxomatous degenerationLeading cause in West(30-70%)Defective fibroelastic tissue floppy valveMost asymptomaticComplicated by annular dilatation,chordal rupture,endocarditisRheumatic disease next most common2021/01/2

11、118MR:Carpentier classificationi.Normal leaflet motionAnnular/ventricular dilatationLeaflet disease/perforation2021/01/2119MR:Carpentier classificationii.Excessive leaflet motion(prolapse)Chordal/papillary muscle elongation or rupture2021/01/2120MR:Carpentier classificationiii.Restricted leaflet/cho

12、rdal motione.g.fibrosis,calcification,retraction 2021/01/2121MR:Aetiology1.Mitral AnnulusMyxomatous degenerationSenile calcificationFunctional dilatation(e.g.myocarditis)Ring abscessMarfans2021/01/2122MR:Aetiology2.Mitral leafletsRheumatic disease,endocarditis(1-30%)Unknown why some develop MS,other

13、s MRFibrocalcific leaflet thickening(without fusion)Chordae shortened,annulus dilatedalso:congenital,connective tissue disease2021/01/2123MR:Aetiology3.ChordaeIschaemiaMyxomatousInfectiveConnective tissueTraumaIdiopathic2021/01/2124MR:Aetiology4.Papillary muscle(10-25%)Dysfunction/ruptureIHD/MI:musc

14、le&annular injuryfrank rupture rare,usually fatalesp.Posteromedial muscleAlso:abscess,sarcoid/amyloid,myocarditisMalalignmente.g.LV aneurysm,dilatation,myopathy2021/01/2125MR:HemodynamicsAcute:J LA pressure,pulm oedemaChronic:LA/PV compliance:i pulm congestnRegurgitant volume depends on:i.Mitral ori

15、fice sizeii.LV-LA pressure gradientiii.Heart rateMedical Tx aims to control above factorsesp.decrease afterload to reduce LV dilatation2021/01/2126MR:Cardiac adaptations LV:h preload,i afterload LV dilated,more spherical,thinned Increased SV(O2 consumption not markedly h)But decompensation can gradu

16、ally occur LA:h size in chronic MR h compliance Less thromboembloism,AF than MS2021/01/2127MR:Symptoms Acute:pulmonary congestion&oedema Chronic:may be prolonged asymptomatic phase Risk of endocarditis Congestive heart failure&fatigue Right heart failure2021/01/2128MR:Investigations CXR:LA/LV enlarg

17、ement ECG:normal;LVH,?AF/arrhythmias Echo:leaflet morphology&function Chamber dimensions,LV function Doppler colour mapping Cardiac catheter:assess coronaries,LV MRI:Dx,LV volumes,regurgitant fraction2021/01/2129MR:Medical therapy Mainstay:Afterload reduction i regurgitant volume i pulm congestion i

18、 LV volume i mitral orifice but:ongoing LV volume overload 10%class I-II progress to III-IV per year Class II-III survival on medical Mx:5 year:50%10 year:25%2021/01/2130MR:Natural history Variable aetiology difficult to predict Difficult to identify those progressing to irreversible LV damage Progn

19、ostic indicators:LV function Degree of regurgitation Underlying aetiology(esp.CAD)2021/01/2131MR:Indications for surgeryAcute:muscle/chordal rupture with shock Immediate MVRChronic,NYHA class II-IV:MVRAim for surgery before irreversible LV changeLV dimension is a predictor of outcome2021/01/2132THANKS FOR WATCHING谢谢大家观看为了方便教学与学习使用，本文档内容可以在下载后随意修改，调整。欢迎下载！时间：20XX.XX.XX汇报人：XXX2021/01/2133