hospital because of mitral restenosis in November 1993, at which time her mitral valve was replaced with a mechanical prosthesis. On the 8th postoperative day, ...
Case Reports
Dissection of the Atrial Wall after Mitral Valve Replacement
LaszI6 Lukacs, MD Imre Kassai, MD
Maria Lengyel, MD
We describe an unusual sequela of mitral valve replacement in a 50-year-old woman who had undergone a closed mitral commissurotomy in 1975. She was admitted to our hospital because of mitral restenosis in November 1993, at which time her mitral valve was replaced with a mechanical prosthesis. On the 8th postoperative day, the patient developed symptoms of heart failure; transesophageal echocardiography revealed dissection and rupture of the left atrial wall. At prompt reoperation, we found an interlayer dissection and rupture of the atrial wall into the left atrium. We repaired the ruptured atrial wall with a prosthetic patch. The postoperative course was uneventful, and postoperative transesophageal echocardiography showed normal prosthetic valve function and no dissection. (Tex Heart Inst J 1996;23:62-4J
upture of the atrioventricular groove or the posterior wall of the left ventricle after mitral valve replacement has been well described; the incidence varies from 0.4% to 7.3%. -P However, dissection of the left atrial wall with subsequent rupture into the left atrium is rare. We report the diagnostic techniques, pathologic findings, and successftLl surgical treatment in a woman who sustained this unusual sequela. To our knowledge, only 1 similar (not identical) case has been published in the world literature.6 R
Case Report In November 1993,
Key words: Heart atrium! pathology; heart rupture; heart valve prosthesis! adverse effects; mitral valve insufficiency From: The Hungarian Institute of Cardiology, 1450 Budapest, Hungary Address for reprints: Laszl6 Lukacs, MD, Hungarian Institute of Cardiology, POB 88, 1450 Budapest, Hungary 62
a 50-year-old woman was admitted to our hospital because of exertional dyspnea. Her medical history included a closed mitral commissurotomy in 1975 and long-standing hypertension. At admission, she was found to be in sinus rhythm and in New York Heart Association functional class III. By echocardiographic examination, the mean diastolic gradient across the mitral valve was estimated as 14 mmHg, and the area was 0.8 cm2. The right ventricular systolic pressure was 74 mmHg. The examination also showed calcified mitral valve leaflets and mild mitral valve insufficiency. Coronary cineangiography revealed normal coronary arteries. The patient underwent surgery through a midsternotomy incision. The ascending aorta and both venae cavae were cannulated for cardiopulmonary bypass, and there was 1 period of aortic cross-clamping. Myocardial protection was achieved with antegrade cold blood cardioplegia and moderate topical cooling (28 °C). The left atrium was opened longitudinally via the interatrial groove, which revealed a mitral valve that was calcified and stenotic due to commissural fusions. The valve was excised and a 27-mm CarboMedics® bileaflet prosthesis (CarboMedics, Inc.; Austin, TX) was implanted with interrupted figure-of-8 sutures. The left atrium was closed and the heart was de-aired. The patient was weaned from cardiopulmonary bypass easily and the immediate postoperative recovery was uneventful. On the 8th postoperative day, the patient developed heart failure and tachyarrhythmias. On auscultation, a holosystolic murmur could be heard over the precordium. Transthoracic and transesophageal 2-dimensional echocardiography demonstrated dissection of the mitral annulus that began close to the aorticomitral continuity and continued into the wall of the left atrium, dividing it into 2 layers. The thinner inner layer ruptured into the cavity of the left atrium (Fig. 1A). Colorflow Doppler echocardiography showed blood regurgitating from the left ven-
Atrial Wall Dissection after Mitral Valve Replacement
Vblume.43, iViiyiiber 1, 1996
Fig. 2 Illustration of the interlayer dissection of the left atrial wall with subsequent rupture into the left atrium. Ao = aorta; LA = left atrium; LV = left ventricle
Fig. 1 A multiplane transesophageal echocardiogram shows A) the dissected left atrial wall (arrows) adjacent to the medial aspect of the mitral prosthesis (MITP). B) Color-flow Doppler imaging of the same cross-section reveals a turbulent regurgitant jet within the dissected area (arrows). LA = left atrium; PA = pulmonary artery
tricle into the dissected atrial wall and fr om this dissected cavity into the left atrium (Fig. 1B). The pulmonary artery systolic pressure, estimated by Doppler echocardiography, had increased to 94 mmHg. A pulmonary artery diastolic pr essure of 33 mmHg was calculated from the end-diastolic pressure gradient between the pulmonary artery and the right ventricle by adding the estimated right atrial pressure. The patient underwent an emergency reoperation. The left atrium was opened, and an interlayer dissection of the left atrial wall with the inner layer rupturing into the left atrium was seen at 10 to 12 o'clock. The interlayer dissection had spr ead to the left ventricle as well (Fig. 2). The ruptur ed atrial wall was closed with an expanded polytetrafluor oethylene patch by use of deep interrupted buttr essed sutures to capture the full thickness of both layers. The lower margin of the patch was sutur ed to the sewing ring of the mitral valve pr osthesis. Intraoperative transesophageal echocardiography showed Texas Heeiil Instifulejournal
no left ventricle-to-left atrium dissection and no r egurgitation (Fig. 3). The patient was weaned fr om cardiopulmonary bypass and the postoperative recovery went well. Thr ee weeks after surgery, transesophageal echocardiography disclosed good prosthetic valve function and no r egurgitation. The patient was asymptomatic when last seen in November of 1995.
Discussion Dissection of the left ventricular wall with ventricular rupture is one of the most danger ous sequelae of mitral valve replacement. Rupture of the posterior atrioventricular groove (Type I) and of the posterior left ventricular wall (T ypes II and III) has been well described.1'2 Surgical repair of these types of ruptur e has proved difficult and carries a very high mortality rate. 1-3 Late rupture of the left ventricle pr esents as a false aneurysm of the left ventricle and pr ovides a better chance for r epair and survival. Interlayer dissection of the left atrial wall and subsequent rupture of the inner layer into the left atrium, which occurred in our patient, has been r eported in just 1 similar case. 6 In our patient, the disruption extended from the anterior part of the mitral valve annulus, which is unusual. The development of the atrial wall dissection was not similar to that of left ventricular rupture. In the latter, sutures placed too deeply in the myocardium may be the cause of the dissection. ' However, in our patient, who sustained atrial dissection, bites placed too shallowly in the annulus may have initiated the pr ocess of disAtrial Wall Dissection after Mitral Valve Replacement
63
References 1.
Karlson KJ, Ashraf MM, Berger RL. Rupture of left ventricle following mitral valve replacement. Ann Thorac Sur g 1988;
46:590-7. 2. Tarkka M, Pokela R, Karkola P. Delayed left ventricular rupture after mitral valve r eplacement. EurJ Cardiothorac Sur g 1987;1: 104-9. 3. DhillonJS, Randhawa GK, Pett SBJr Successful repair of left ventricular rupture after redo mitral valve replacement. Ann Thorac Surg 1989;47:916-7. 4. David TE, Feindel CM. Reconstruction of the mitral anulus. Circulation 1987;76(3 Pt 2):III-102-7. 5. Otaki M, Kitamura N. Left ventricular ruptur e following mitral valve replacement. Chest 1993;104:1431-5. 6. Pretre R, Murith N, Neidhart P, Luthi P, Faidutti B. Dissection of the atrial septum following mitral valve sur gery. J Card
Surg 1994;9:61-4. 7. Verkkala K, Maamies T, Kupari M, Mattila T, Ala-Kulju K. Pseudoaneurysm of the left ventricle following mitral valve replacement. j Cardiovasc Surg 1990;31:242-6.
Fig. 3 A postoperative multiplane transesophageal echocardiogram of A) a cross-section similar to that in Fig. 1. B) Results of postoperative color-flow Doppler imaging of the same cross-section are consistent with normal prosthetic valve function: there are 2 laminar central regurgitant jets into the left atrium and there is no paravalvular regurgitation. LA = left atrium; MITP = mitral valve prosthesis; PA = pulmonary artery
ruption, and the dissection between the layers of the atrial wall may have pr ogressed as blood was ejected through the disrupted tissue at each systole. For tunately, the rupture diverted blood into the left atrium and not outward into the pericardial cavity. After the precise diagnosis (made possible by echocardiography), this unusual adverse ef fect was successfully repaired. To prevent this serious sequela, faulty suturing and forceful traction on the annulus should be avoided during excision of the valve and insertion of the prosthesis. The dissection may be caused by a combination of factors; therefore, the valve structures must be handled very gently during mitral valve replacement, and care must be taken to pr event postoperative hypertension.
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Atrial Wall Dissection after Mitral Valve Replacement
'Vblume Z3, Ntimber 1, 1996
