Outcomes of Mitral Valve Repair for Mitral Regurgitation Due to Degenerative Disease

Transcription

1 Outcomes of Mitral Valve Repair for Mitral Regurgitation Due to Degenerative Disease TIRONE E. DAVID, MD ; SEMIN THORAC CARDIOVASC SURG 19: c 2007 ELSEVIER INC. PRESENTED BY INTERN 許士盟 Mitral valve repair Introduction the standard surgical treatment for MR due to mitral valve prolapse caused by degenerative disease. mortality and morbidity low early failures are uncommon Does not cure the pathologic process Degenerative disorder continue to progress and cause recurrent MR. This study describes the author s experience Patients and Methods From July 1981 through June patients with MR: Due to degenerative disease of the mitral valve underwent mitral valve repair by one surgeon. Excluded: aortic valve disease Included: tricuspid insufficiency or CAD The degree of myxomatous degeneration was recorded as mild, moderate, and severe by: Thickness of the leaflets and chordae tendineae Size of the leaflets Interchordal hooding of the leaflets Most had myxomatous degeneration 11% had fibroelastic deficiency 2% had dystrophic calcification of the mitral annulus with MR Operative Techniques Operative Techniques(1) Prolapse of the posterior leaflet was corrected by: quadrangular, rectangular, or triangular resection with or without sliding plasty Posterior leaflet with normal height and ruptured chordae tendineae: ex: fibroelastic deficiency was corrected by creating multiple new chords of 5 or 6-0 Gore-Tex

2 Operative Techniques(2) Operative Techniques(3) Prolapse of the anterior leaflet was corrected by: triangular resection, chordal transfer, or chordal shortening until 1990 largely substituted by chordal replacement with Gore-Tex sutures Since 1995, patients with advanced myxomatous degeneration and posterior displacement of the mitral annulus: entire posterior leaflet detached from its insertion false commissures closed with interrupted sutures all secondary chordae severed height shortened to approximately 12 mm posterior annuloplasty sutures were passed through the endocardium of the left ventricle and the displaced annulus the posterior leaflet was sutured to the endocardium at the level where these sutures were applied an annuloplasty band: reduce the area of the mitral annulus Operative Techniques(4) Operative Techniques(5) A small number of patients with dystrophic calcification of the mitral annulus had valve repair by: detaching the posterior leaflet from the calcified annulus excising the calcium bar reconstructing the annulus with fresh, autologous pericardial patch reattaching the posterior leaflet to the pericardial patch correcting leaflet prolapse as needed An annuloplasty was performed on all patients except: the mitral annulus was small (30 mm) MR was due to fibroelastic deficiency Operative Techniques(6) Follow-up Intraoperative transesophageal echocardiography used in all patients since 1988 no patient left the operating room with more than mild MR systolic anterior motion of the anterior leaflet of the mitral valve with obstruction of the left ventricular outflow tract All patients were treated with: warfarin sodium during the first post-op 3 months Permanently in atrial fibrillation Visited cardiologist every 1 year echocardiogram at least every 2nd year MR was recorded as none, trivial(1+), mild(2+), moderate(3+), and severe(4+) mild to moderate, -> moderate moderate to severe, -> severe Severe, recurrent MR were assessed to determine the further surgical treatment Extended from 0 to 22 years (mean, years) Closed on January 31, 2005

3 Result Results(1) 4 operative and 94 late deaths: 17: valve-related, 30: cardiac, and 47: noncardiac deaths Cox regression analysis identified the predictors of death: age + 5 years New York Heart Association functional classes 3 and 4 LV EF< 40% CAD by univariate analysis only. 6 patients experienced 1 thromboembolic events 38 had strokes, and 22 had transient ischemic attacks The freedom from thromboembolic events: 5 years: 94 1% 10 years: 87 2% 15 years: 80 4% Results(2) Results(3) 7 patients developed infective endocarditis: 3: treated surgically; 4: with antibiotics All survived The freedom from infective endocarditis: 5 years : % 10 years : % 15 years : % 126 patients on oral anticoagulant atrial fibrillation or previous embolic event 10 patients: major hemorrhage 6 died 26 patients required reoperation on the mitral valve: 3: endocarditis 3: mitral stenosis due to pannus 1: a fistula between the LV and the coronary sinus 19: recurrent MR (4 of whom had hemolytic anemia) 2 had coronary artery bypass 1 had aortic root replacement, but the mitral valve was left alone No operative death Results(4): follow-up Results(5): follow-up During the follow-up: Severe MR: 27 pts ; moderate MR: 51 pts ; mild MR: 173 pts Cox regression analysis identified predictive factors of MR: severe myxomatous changes in the leaflets anterior or bileaflet prolapse LV EF< 40% Risk of recurrent MR: > 2: severe tricuspid insufficiency 2: mild systolic anterior motion of the anterior leaflet of the mitral valve without MR or obstruction of the LV outflow tract At the latest follow-up contact: 525 patients were alive and free from reoperation on the mitral valve 368 ( 70%) in New York Heart Association functional class I 105 (20%) in class II 52 (10%) in class III

4 Discussion(1) Degenerative disease of the mitral valve: most common: myxomatous degeneration The degree varies widely in patients need surgery. mild to moderate degree in the leaflets and chordae tendineae Prolapse due to chordal elongation or rupture. Central scallop of the posterior leaflet is the most commonly involved segment with prolapse medial half of the mitral valve> lateral half Barlow s syndrome : Particularly younger ones Discussion(2) Advanced myxomatous changes of the mitral valve Both leaflets voluminous, prolapse into the left atrium Mitral annulus grossly dilated and posteriorly displaced. the posterior leaflet attachment often displaced from the endocardium of the left ventricle gap between the ventricle and leaflet up to 1 cm Repair these valves, the posterior leaflet should be reattached to the endocardium of the left ventricle Fibroelastic deficiency: leaflets are grossly normal Discussion(3) chordae tendineae are thinner than normal MR due to ruptured chordae. the central scallop of the posterior leaflet is the most commonly affected segment The mitral annulus is not grossly dilated unless the MR is longstanding and the ventricle is dilated Usually older than those with gross myxomatous changes of the mitral valve Discussion(4) Dystrophic calcification of the mitral annulus usually older younger patients with advanced myxomatous degeneration of the mitral valve Although these valves can be repaired, they often require replacement. the calcium bar should be removed the atrioventricular junction should be reconstructed with a strip of pericardial patch. Complicated operative procedure but probably the only effective way Discussion(5) Discussion(6) Echocardiography is the best diagnostic tool for MR Determine its mechanism assess reparability of the valve 95% of patients can have mitral valve repair transesophageal echocardiogram is performed preoperatively, nears 100% Recommend mitral valve repair in asymptomatic patients with severe MR operative risk is 1% high predictability of repair advanced functional class adversely affects long-term survival The operative mortality: 1% during the past 2 decades Intraoperative transesophageal echocardiography must be used no residual MR morphology of the valve satisfactory: the leaflets coaptation depth >5 mm from commissure to commissure no segment should be prolapsing. Residual moderate or severe MR requires operative revision Residual mild MR may be left alone if the morphology is satisfactory

5 Discussion(7) Systolic anterior motion of the mitral valve with MR and obstruction of the LV outflow tract largely eliminated by: reducing the height of the posterior leaflet to 12 mm avoiding small annuloplasty rings or bands. Mascagni and colleagues: described 4 patients resolved by adding the Alfieri s stitch between the central portions of the free margins of the anterior and posterior leaflets. Mayo Clinic reviews: 2.3% of patients developed late reoperation was not required the late survival and functional classes of patients with and without obstruction were similar Discussion(8) Degenerative disease is progressive and mitral valve repair does not arrest the process. The freedom from late, recurrent MR > 3+:85 4% at 15 years, and for 2+: 70 4%. The freedom from reoperation was 92 3% at 15 years. In previous study: Late, recurrent MR more likely to occur in patients with more complex lesions The freedom from severe, recurrent MR after repair of the posterior leaflet was 92% at 12 years The anterior or bileaflet prolapse was 86% Discussion(9) Summary Mohty and associates: found reoperation rate at 15 years: anterior leaflet prolapse: 28 7 % posterior leaflet prolapse: 11 3% The reoperation rate at 10 years fell from 24% to 10% from the 1980s to 1990s in patients with anterior leaflet prolapse. De Bonis and colleagues from Milan, Italy: the freedom from reoperation at 10 years was 96% for both posterior leaflet prolapse and anterior leaflet prolapse treated with the Alfieri s stitch. Mitral valve repair for MR due to degenerative disease of the mitral valve: low operative mortality and morbidity low rates of recurrent MR Surgery should be offered to all symptomatic and selected asymptomatic patients with severe MR diagnostic accuracy of this lesion the predictability of repair current knowledge of the natural history