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Left ventricular outflow obstruction: A complication of mitral valvuloplasty
825
lA CC \ " I 4. No 4
October 984 825-8
Left Ventricular Outflow Obstruction: A Complication of Mitral Valvuloplasty ITZHAK KRONZON, MD,* MURRAY L. COHEN, MD,* HOWARD E. WINER, MD,* STEPHEN B. COLVIN, MDt New York . New York
Thirty-two patients with severe mitral regurgitation underwent Carpentier mitral valvuloplasty. Postoperatively, three of these patients developed clinical and echocardiographic evidence of left ventricular outflow tract obstruction. None of these patients had asymmetric septal hypertrophy or preoperative echocardiographic demonstration of systolic anterior motion of the mitral valve.
Severe , symptomatic mitral regurgitation usually requires mitral valve replacement. During the last 13 years, however, selected patients have undergone reconstructi ve surgery of the mitral valve . The most extensive surgical experience has been that of Carpentier et al. ( I), who described the technique in detail and provided follow-up information on the largest series of patients to date. During the last 3 years, 32 patients with severe mitral regurgitation underwent mitral valvuloplasty according to the Carpentier technique at our medical center. Three of these patients developed left ventricular outflow obstruction due to systolic anterior motion of the anterior mitral leaflet. None of these patients had evidence of hypertrophic card iomyopathy before operation . One of these patients has been previous ly described (2). We report on two additional patients with left ventricular outflow obstruction after Carpentier mitral valvuloplasty and discuss possible mechanisms of this complic ation .
Case Reports Case 1 A 58 year old white man had had a heart murmur since childhood . He was asymptomatic until November 1981, when he was involved in a car accident which resulted in severe chest trauma . After the accident , he noted the onset
From the Departments of Medicme* and Surgery.t New York Urnversuy Medical Center. New York, New York. Manuscnpl received March 28. 1484, accepted May 18, 1984 Address for reprints; Itzhak Kronzon, MD, 560 FIrst Avenue. SUIte 2E, New York, New York 10016. © 1984 by the American College of Cardiology
Outflow obstruction postoperatively was caused by systolic anterior motion of the mitral valve. Because this potential complication of Carpentier mitral valvuloplasty produced significant hemodynamic effects in two patients, echocardiography should be routinely performed after this operation.
of exertiona l dyspnea. His blood pressure was 124/80 mm Hg and his pulse was 72 beats/m in and regular. A grade 4/6 holosystolic murmur was audible at the apex . There were no signs of congestive heart failure. M-mode echocardiography showed a moderately enlarged left ventricle (end-diastolic dimension 6.2 ern) and a slightly dilated left atrium (4.5 em ). Holosystolic mitral valve prolapse was noted. Two-dimensional echocardiography revealed a well contracting left ventricle , severe mitral valve prolapse and a flail posterior leaflet. Neither asymmetric septal hypertrophy nor systolic anterior motion of the anterior mitral leaflet was present. Doppler echocardiography confirmed severe mitral regurgitation. Cardiac catheterization demonstrated a left atrial CY wave of 60 mm Hg and a mean left atrial pressure of 33 mm Hg. The left ventricular end-diastolic pressure was moderately elevated . There was no pressure gradient across the mitral valve during diastole or across the left ventricular outflow tract during systole . Left ventricular angiography showed severe mitral regurgitation and a well contracting left ventricle . At operation , severe mitral regurgitation secondary to prolapse of the posterior leaflet of the mitral valve was found. The mitral anulus was dilated and deformed. Carpentier valvuloplast y was performed with wedge resection of 50% of the posterior mitral leaflet and shortening of its chordae tendineae. A 32 mm Carpentier ring was inserted as previously described ( l ). The immediate postoperat ive course was unremarkabl e and the murmur of mitral regurgitation disappeared. Follow-up, Ten days after discharge, the patient was readmitted to the hospital because of palpitation and easy 0735·10971841$3.00
KRONZON ET AL LEFT VENTRICULAR OUTFLOW OBSTRUCTION
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lACC Vol 4. No 4 October 1984'825-8
fatigability. The physical examination and the electrocardiogram revealed atrial fibrillation with a rapid ventricular response. The patient was treated with digoxin and the rhythm reverted to regular sinus rhythm. A few days later, the patient noted marked fatigue. Dizziness was precipitated by standing. Physical examination now revealed a systolic ejection murmur along the left sternal border, which became louder in the erect position after Valsalva maneuver and after premature contractions. His systolic blood pressure decreased to 70 mm Hg when standing. M-mode echocardiography revealed the characteristic findings usually seen after mitral valvuloplasty by the Carpentier method (3). The mitral prosthetic ring could be seen easily, and the mitral valve area was normal. The left atrium was dilated. In addition to this finding, an abnormal systolic anterior motion of the anterior mitral leaflet was clearly visualized (Fig. 1). This leaflet made contact with the ventricular septum during systole, a finding that is suggestive of outflow obstruction. The systolic anterior motion became more prominent after ventricular premature contractions. Two-dimensional echocardiography revealed that the anterior mitral leaflet became sharply angulated and protruded into the left ventricular outflow tract during systole. Doppler echocardiography revealed no evidence of mitral regurgitation. There was a high peak flow velocity in the left ventricular outflow tract, which suggested a left ventricular pressure gradient of 30mm Hg. The patient's digoxin was discontinued and he was given propranolol, 20 mg four times daily, as well as quinidine, 200 mg four times daily. He remained in normal sinus
Figure 1. Patient 1, M-mode echocardiogram. A,This demonstrates normal septal thickness, systolic anterior motion of the anterior mitral leaflet and the characteristic findings of Carpentier ring in the mitral position, namely, the dense echoes that represent the anterior (AR) and posterior (PR) aspect of the ring. B, The systolic anterior motion (SAM) is more prominent after a premature contraction. Ao = aortic root; LA = left atrium; MV = mitral valve; RV = right ventricle; S = septum.
A
.. _ :"~ " - _ .:.~.~,.~.. _ -:: . .~ __ . ~ . . _ - . ' " "
rhythm. His symptoms of dizziness and easy fatigability disappeared. The systolic murmur was audible only during the Valsalva maneuver. Echocardiography showed that the abnormal systolic anterior motion of the anterior mitral leaflet was not present unless provoked by inhalation of amyl nitrite or the Valsalva maneuver. The patient has remained asymptomatic.
Case 2 A 49 year old white man had a heart murmur for 20 years. Symptoms of shortness of breath on exertion started 3 years before this admission and progressed gradually. He developed orthopnea and I month before admission, he was treated for pulmonary edema. Physical examination revealed a moderately dyspneic patient. The blood pressure was 110/85 mm Hg. There was no jugular venous distension. The carotid pulses were normal. Examination of the heart revealed a regular rate of 110 beats/min; S, was normal, S2 was physiologically split and an S3 gallop was present. A grade 4/6 holosystolic murmur was audible over the entire precordium; it was loudest over the apex and radiated to the axilla. The electrocardiogram showed sinus tachycardia, P mitrale and diffuse nonspecific ST and T changes. The echocardiogram showed severe mitral valve prolapse, a flail posterior mitral leaflet, left atrial and left ventricular dilation and a hyperkinetic left ventricle. There was no asymmetric septal hypertrophy or systolic anterior motion of the anterior mitral leaflet. Cardiac catheterization confirmed the clinical impression of severe mitral regurgitation. There was no transmitral pressure gradient or evidence of an aortic or subaortic pressure gradient. The coronary arteries were normal. At operation, the mitral ring was dilated. Severe prolapse of the mitral valve and ruptured chordae tendineae were noted. A Carpentier mitral valvuloplasty was performed. Postoperatively, the murmur of mitral regurgitation disappeared. On the fourth postoperative day, a systolic murmur was present at the left sternal border and at the base. The murmur did not radiate to the neck.
- - - .. . : ...~; . . ~~: - " -~~ - i~ \
.--
-
RV IV
Iff
JACC \ .. I. 4. No 4 October 984 825-8
KRONZON ET AI. LEFT VENTRICULAR OUTFLOW OBSTR UCT IO N
Echacardiograph y was repeated. The characteristic findings of Carpentier mitral valvuloplasty (3) were present , as was a moderate pericardial effusion. Abnormal systolic anterior motion of the anterior mitral leaflet was identified, the leaflet making contact with the interventricular septum during systole . This finding was confirmed on two-dimen sional echocardiography, which showed sharp angulation of the anterior leaflet with systolic obstruction of the left ventricular outflow tract. Mid-systolic closure of the aortic valve was visualized (Fig . 2). There was Doppler echocardiographic evidence of high peak flow velocity, suggesting a pressure gradient of 90mm Hg across the left ventricular outflow tract. There was no evidence of mitral regurgitation by Doppler echocardiography, and septal hypertrophy was not present. The patient's digoxin was discontinued and over the next week . the intensity of the murmur diminished. Repeated echocardiography showed that the pericardial effusion had resolved and the systolic anterior motion of the anterior mitral leaflet was no longer present. However , amyl nitrite inhalation produced abnormal systolic motion of the mitral valve. The patient remained asymptomatic and was discharged in good condition.
Discussion Carpentier et al. (1,4) reported the largest series of patients followed up after prosthetic ring anuloplasty of the mitral valve. They reported a 4% hospital mortality rate. Reoperation for mitral insufficiency or stenosis was performed in 7% of their patients at 2 years, and in 13% at 8 years. In a recent report (3), we evaluated 13 patients who had undergone Carpentier mitral valvuloplasty at our institution . M-mode, two-dimen sional and Doppler echocard iography were utilized in all patients. and the findings were
827
correlated with data from hemodynamic studies, cardiac catheterization and angiography. Preoperati vely, each of the 13 patients had severe, symptomatic mitral regurgitation. After operation , each patient had symptomatic relief and the murmur of mitral regurgitat ion disappeared . Postoperative echocardiography in the 13 patients showed that the mitral valve EF slope had a significantly diminished excursion . The mitral valve area also decreased. In each patient, M-mode echocardiography demonstrated two parallel , dense linear echoes near the base of the mitral valve which arose from the prosthetic ring . Two-dimensional echocardiography revealed the entire extent of the ring. Doppler echocardiography suggested the disappearance of mitral regurgitation in most patients. Our two patients had an additional finding. In each patient , a murmur suggesting the diagno sis of left ventricular outflow obstruction was noted . This diagnosis was supported by the demonstrat ion of abnormal systolic anterior motion of the anterior mitral leaflet, as well as by Doppler evidence of a pressure gradient across the left ventricular outflow tract. A third patient in our operative group had similar echocardiographic findings and was reported previously (2). Etiology. The cause of this unusual finding is not clear, although several hypotheses can be made. It is possible that surgically induced changes in left ventricular, chordal and mitral geometry are responsible for abnormal systolic anterior motion of the anterior mitral leaflet. Asymptomatic systolic anterior motion of the anterior mitral leaflet was noted previously in one patient who underwent mitral valvular repair and anuloplasty without the use of a Carpentier ring (5). The insertion of the semirigid Carpentier ring may itself produce unusual systolic anterior motion of the mitral valve. Normally, the mitral anulus decreases in size during systole. The anterior part of the anulus moves posteriorly,
RV
Figure 2. Patient 2, postoperative M-mode echocardiogram. Left, At the mitral valve (MY) level. Note the normal septal thickness and the dense echoe s from the Carpentier ring (CR). Abnormal systolic anterior motion (SAM) of the mitral valve causes left ventricular outflow obstruction. Right, At the level of the aorta . Note the mid-systolic aortic valve closure (arrows) and the dilated left atrium . Abbreviations as in Figure I.
Ao
LA
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lACC Vol 4. No 4 October I'IS4 S25-S
KRONZON ET AL LEFf VENTRICULAR OUTFLOW OBSTRUCTION
together with the base of the anterior mitral leaflet. The backward motion of the anterior leaflet increases the size of the left ventricular outflow tract and prevents its narrowing during systole. With the insertion of a rigid ring, this backward excursion is diminished. This may result in a narrower left ventricular outflow tract, which may in tum cause systolic anterior motion of the anterior mitral leaflet by the Bernoulli effect. Lindval and Herrlin (6) described abnormal systolic anterior motion of the anterior mitral leaflet in patients with mitral anular calcification and no evidence of asymmetric septal hypertrophy. A similar mechanism may be invoked to explain systolic anterior motion in such patients with a rigid mitral anulus. The reduction in left ventricular volume after correction of mitral regurgitation may contribute to the postoperative presence of a left ventricular outflow tract gradient. The delay in the presence of physical findings is consistent with this mechanism. A combination of digitalis therapy, which causes increased contractility, with pericardial effusion and possible dehydration in Patient 2 may result in the hemodynamic milieu for abnormal systolic anterior motion. However, both patients continued to have provocable mitral valve systolic anterior motion and a murrnur after digitalis was discontinued and the pericardial effusion resolved. Invasive hemodynamic verification of the presence of left ventricular outflow tract obstruction is not available in these patients. However, the clinical and echocardiographic findings are
so characteristic of this diagnosis that invasive procedures were not warranted in these asymptomatic patients. Implications. The development of dynamic left ventricular outflow obstruction after mitral anuloplasty and valvuloplasty occurred in 3 (9%) of 32 of the patients operated on in our institution. We are not aware that this complication has occurred in the experience of other groups performing Carpentier mitral valvuloplasty. This potentially serious complication should be looked for in any patient who undergoes this operation.
References I. Carpentier A, Fabinai lN, Reiland 1. Reconstructive surgery of the mitral valve incompetence. Ten year appraisal. 1 Thorac Cardiovasc Surg 1980;79:338-48. 2. Gallerstein PE, Berger M, Rubenstein S, Berdoff RL, Goldberg E. Systolic anterior motion of the mitral valve and outflow obstruction after mitral valve reconstruction. Chest 1983;83:819-20. 3. Kronzon L Mercurio P, Winer HE, Colvin S. Noninvasive evaluation of mitral valvuloplasty. Am Heart 1 1983;106:362-8. 4. Carpentier A, Deloche A, Dauptain 1, et al. A new reconstructive operation for correction of mitral and tricuspid valve insufficiency. 1 Thorac Cardiovasc Surg 1971;61:1-13. 5. Termini BA, lackson PA, Williams CD. Systolic anterior motion of the mitral valve following annuloplasty. Vase Surg 1977;11:55-60. 6. Lindvall K, Herrlin B Mitral annulus calcification, systolic anterior motion of the antenor mitral leaflet and outflow obstruction m two patients without hypertrophic cardiomyopathy. Acta Med Scand 1981;209:513-8.
lA CC \ " I 4. No 4
October 984 825-8
Left Ventricular Outflow Obstruction: A Complication of Mitral Valvuloplasty ITZHAK KRONZON, MD,* MURRAY L. COHEN, MD,* HOWARD E. WINER, MD,* STEPHEN B. COLVIN, MDt New York . New York
Thirty-two patients with severe mitral regurgitation underwent Carpentier mitral valvuloplasty. Postoperatively, three of these patients developed clinical and echocardiographic evidence of left ventricular outflow tract obstruction. None of these patients had asymmetric septal hypertrophy or preoperative echocardiographic demonstration of systolic anterior motion of the mitral valve.
Severe , symptomatic mitral regurgitation usually requires mitral valve replacement. During the last 13 years, however, selected patients have undergone reconstructi ve surgery of the mitral valve . The most extensive surgical experience has been that of Carpentier et al. ( I), who described the technique in detail and provided follow-up information on the largest series of patients to date. During the last 3 years, 32 patients with severe mitral regurgitation underwent mitral valvuloplasty according to the Carpentier technique at our medical center. Three of these patients developed left ventricular outflow obstruction due to systolic anterior motion of the anterior mitral leaflet. None of these patients had evidence of hypertrophic card iomyopathy before operation . One of these patients has been previous ly described (2). We report on two additional patients with left ventricular outflow obstruction after Carpentier mitral valvuloplasty and discuss possible mechanisms of this complic ation .
Case Reports Case 1 A 58 year old white man had had a heart murmur since childhood . He was asymptomatic until November 1981, when he was involved in a car accident which resulted in severe chest trauma . After the accident , he noted the onset
From the Departments of Medicme* and Surgery.t New York Urnversuy Medical Center. New York, New York. Manuscnpl received March 28. 1484, accepted May 18, 1984 Address for reprints; Itzhak Kronzon, MD, 560 FIrst Avenue. SUIte 2E, New York, New York 10016. © 1984 by the American College of Cardiology
Outflow obstruction postoperatively was caused by systolic anterior motion of the mitral valve. Because this potential complication of Carpentier mitral valvuloplasty produced significant hemodynamic effects in two patients, echocardiography should be routinely performed after this operation.
of exertiona l dyspnea. His blood pressure was 124/80 mm Hg and his pulse was 72 beats/m in and regular. A grade 4/6 holosystolic murmur was audible at the apex . There were no signs of congestive heart failure. M-mode echocardiography showed a moderately enlarged left ventricle (end-diastolic dimension 6.2 ern) and a slightly dilated left atrium (4.5 em ). Holosystolic mitral valve prolapse was noted. Two-dimensional echocardiography revealed a well contracting left ventricle , severe mitral valve prolapse and a flail posterior leaflet. Neither asymmetric septal hypertrophy nor systolic anterior motion of the anterior mitral leaflet was present. Doppler echocardiography confirmed severe mitral regurgitation. Cardiac catheterization demonstrated a left atrial CY wave of 60 mm Hg and a mean left atrial pressure of 33 mm Hg. The left ventricular end-diastolic pressure was moderately elevated . There was no pressure gradient across the mitral valve during diastole or across the left ventricular outflow tract during systole . Left ventricular angiography showed severe mitral regurgitation and a well contracting left ventricle . At operation , severe mitral regurgitation secondary to prolapse of the posterior leaflet of the mitral valve was found. The mitral anulus was dilated and deformed. Carpentier valvuloplast y was performed with wedge resection of 50% of the posterior mitral leaflet and shortening of its chordae tendineae. A 32 mm Carpentier ring was inserted as previously described ( l ). The immediate postoperat ive course was unremarkabl e and the murmur of mitral regurgitation disappeared. Follow-up, Ten days after discharge, the patient was readmitted to the hospital because of palpitation and easy 0735·10971841$3.00
KRONZON ET AL LEFT VENTRICULAR OUTFLOW OBSTRUCTION
826
lACC Vol 4. No 4 October 1984'825-8
fatigability. The physical examination and the electrocardiogram revealed atrial fibrillation with a rapid ventricular response. The patient was treated with digoxin and the rhythm reverted to regular sinus rhythm. A few days later, the patient noted marked fatigue. Dizziness was precipitated by standing. Physical examination now revealed a systolic ejection murmur along the left sternal border, which became louder in the erect position after Valsalva maneuver and after premature contractions. His systolic blood pressure decreased to 70 mm Hg when standing. M-mode echocardiography revealed the characteristic findings usually seen after mitral valvuloplasty by the Carpentier method (3). The mitral prosthetic ring could be seen easily, and the mitral valve area was normal. The left atrium was dilated. In addition to this finding, an abnormal systolic anterior motion of the anterior mitral leaflet was clearly visualized (Fig. 1). This leaflet made contact with the ventricular septum during systole, a finding that is suggestive of outflow obstruction. The systolic anterior motion became more prominent after ventricular premature contractions. Two-dimensional echocardiography revealed that the anterior mitral leaflet became sharply angulated and protruded into the left ventricular outflow tract during systole. Doppler echocardiography revealed no evidence of mitral regurgitation. There was a high peak flow velocity in the left ventricular outflow tract, which suggested a left ventricular pressure gradient of 30mm Hg. The patient's digoxin was discontinued and he was given propranolol, 20 mg four times daily, as well as quinidine, 200 mg four times daily. He remained in normal sinus
Figure 1. Patient 1, M-mode echocardiogram. A,This demonstrates normal septal thickness, systolic anterior motion of the anterior mitral leaflet and the characteristic findings of Carpentier ring in the mitral position, namely, the dense echoes that represent the anterior (AR) and posterior (PR) aspect of the ring. B, The systolic anterior motion (SAM) is more prominent after a premature contraction. Ao = aortic root; LA = left atrium; MV = mitral valve; RV = right ventricle; S = septum.
A
.. _ :"~ " - _ .:.~.~,.~.. _ -:: . .~ __ . ~ . . _ - . ' " "
rhythm. His symptoms of dizziness and easy fatigability disappeared. The systolic murmur was audible only during the Valsalva maneuver. Echocardiography showed that the abnormal systolic anterior motion of the anterior mitral leaflet was not present unless provoked by inhalation of amyl nitrite or the Valsalva maneuver. The patient has remained asymptomatic.
Case 2 A 49 year old white man had a heart murmur for 20 years. Symptoms of shortness of breath on exertion started 3 years before this admission and progressed gradually. He developed orthopnea and I month before admission, he was treated for pulmonary edema. Physical examination revealed a moderately dyspneic patient. The blood pressure was 110/85 mm Hg. There was no jugular venous distension. The carotid pulses were normal. Examination of the heart revealed a regular rate of 110 beats/min; S, was normal, S2 was physiologically split and an S3 gallop was present. A grade 4/6 holosystolic murmur was audible over the entire precordium; it was loudest over the apex and radiated to the axilla. The electrocardiogram showed sinus tachycardia, P mitrale and diffuse nonspecific ST and T changes. The echocardiogram showed severe mitral valve prolapse, a flail posterior mitral leaflet, left atrial and left ventricular dilation and a hyperkinetic left ventricle. There was no asymmetric septal hypertrophy or systolic anterior motion of the anterior mitral leaflet. Cardiac catheterization confirmed the clinical impression of severe mitral regurgitation. There was no transmitral pressure gradient or evidence of an aortic or subaortic pressure gradient. The coronary arteries were normal. At operation, the mitral ring was dilated. Severe prolapse of the mitral valve and ruptured chordae tendineae were noted. A Carpentier mitral valvuloplasty was performed. Postoperatively, the murmur of mitral regurgitation disappeared. On the fourth postoperative day, a systolic murmur was present at the left sternal border and at the base. The murmur did not radiate to the neck.
- - - .. . : ...~; . . ~~: - " -~~ - i~ \
.--
-
RV IV
Iff
JACC \ .. I. 4. No 4 October 984 825-8
KRONZON ET AI. LEFT VENTRICULAR OUTFLOW OBSTR UCT IO N
Echacardiograph y was repeated. The characteristic findings of Carpentier mitral valvuloplasty (3) were present , as was a moderate pericardial effusion. Abnormal systolic anterior motion of the anterior mitral leaflet was identified, the leaflet making contact with the interventricular septum during systole . This finding was confirmed on two-dimen sional echocardiography, which showed sharp angulation of the anterior leaflet with systolic obstruction of the left ventricular outflow tract. Mid-systolic closure of the aortic valve was visualized (Fig . 2). There was Doppler echocardiographic evidence of high peak flow velocity, suggesting a pressure gradient of 90mm Hg across the left ventricular outflow tract. There was no evidence of mitral regurgitation by Doppler echocardiography, and septal hypertrophy was not present. The patient's digoxin was discontinued and over the next week . the intensity of the murmur diminished. Repeated echocardiography showed that the pericardial effusion had resolved and the systolic anterior motion of the anterior mitral leaflet was no longer present. However , amyl nitrite inhalation produced abnormal systolic motion of the mitral valve. The patient remained asymptomatic and was discharged in good condition.
Discussion Carpentier et al. (1,4) reported the largest series of patients followed up after prosthetic ring anuloplasty of the mitral valve. They reported a 4% hospital mortality rate. Reoperation for mitral insufficiency or stenosis was performed in 7% of their patients at 2 years, and in 13% at 8 years. In a recent report (3), we evaluated 13 patients who had undergone Carpentier mitral valvuloplasty at our institution . M-mode, two-dimen sional and Doppler echocard iography were utilized in all patients. and the findings were
827
correlated with data from hemodynamic studies, cardiac catheterization and angiography. Preoperati vely, each of the 13 patients had severe, symptomatic mitral regurgitation. After operation , each patient had symptomatic relief and the murmur of mitral regurgitat ion disappeared . Postoperative echocardiography in the 13 patients showed that the mitral valve EF slope had a significantly diminished excursion . The mitral valve area also decreased. In each patient, M-mode echocardiography demonstrated two parallel , dense linear echoes near the base of the mitral valve which arose from the prosthetic ring . Two-dimensional echocardiography revealed the entire extent of the ring. Doppler echocardiography suggested the disappearance of mitral regurgitation in most patients. Our two patients had an additional finding. In each patient , a murmur suggesting the diagno sis of left ventricular outflow obstruction was noted . This diagnosis was supported by the demonstrat ion of abnormal systolic anterior motion of the anterior mitral leaflet, as well as by Doppler evidence of a pressure gradient across the left ventricular outflow tract. A third patient in our operative group had similar echocardiographic findings and was reported previously (2). Etiology. The cause of this unusual finding is not clear, although several hypotheses can be made. It is possible that surgically induced changes in left ventricular, chordal and mitral geometry are responsible for abnormal systolic anterior motion of the anterior mitral leaflet. Asymptomatic systolic anterior motion of the anterior mitral leaflet was noted previously in one patient who underwent mitral valvular repair and anuloplasty without the use of a Carpentier ring (5). The insertion of the semirigid Carpentier ring may itself produce unusual systolic anterior motion of the mitral valve. Normally, the mitral anulus decreases in size during systole. The anterior part of the anulus moves posteriorly,
RV
Figure 2. Patient 2, postoperative M-mode echocardiogram. Left, At the mitral valve (MY) level. Note the normal septal thickness and the dense echoe s from the Carpentier ring (CR). Abnormal systolic anterior motion (SAM) of the mitral valve causes left ventricular outflow obstruction. Right, At the level of the aorta . Note the mid-systolic aortic valve closure (arrows) and the dilated left atrium . Abbreviations as in Figure I.
Ao
LA
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lACC Vol 4. No 4 October I'IS4 S25-S
KRONZON ET AL LEFf VENTRICULAR OUTFLOW OBSTRUCTION
together with the base of the anterior mitral leaflet. The backward motion of the anterior leaflet increases the size of the left ventricular outflow tract and prevents its narrowing during systole. With the insertion of a rigid ring, this backward excursion is diminished. This may result in a narrower left ventricular outflow tract, which may in tum cause systolic anterior motion of the anterior mitral leaflet by the Bernoulli effect. Lindval and Herrlin (6) described abnormal systolic anterior motion of the anterior mitral leaflet in patients with mitral anular calcification and no evidence of asymmetric septal hypertrophy. A similar mechanism may be invoked to explain systolic anterior motion in such patients with a rigid mitral anulus. The reduction in left ventricular volume after correction of mitral regurgitation may contribute to the postoperative presence of a left ventricular outflow tract gradient. The delay in the presence of physical findings is consistent with this mechanism. A combination of digitalis therapy, which causes increased contractility, with pericardial effusion and possible dehydration in Patient 2 may result in the hemodynamic milieu for abnormal systolic anterior motion. However, both patients continued to have provocable mitral valve systolic anterior motion and a murrnur after digitalis was discontinued and the pericardial effusion resolved. Invasive hemodynamic verification of the presence of left ventricular outflow tract obstruction is not available in these patients. However, the clinical and echocardiographic findings are
so characteristic of this diagnosis that invasive procedures were not warranted in these asymptomatic patients. Implications. The development of dynamic left ventricular outflow obstruction after mitral anuloplasty and valvuloplasty occurred in 3 (9%) of 32 of the patients operated on in our institution. We are not aware that this complication has occurred in the experience of other groups performing Carpentier mitral valvuloplasty. This potentially serious complication should be looked for in any patient who undergoes this operation.
References I. Carpentier A, Fabinai lN, Reiland 1. Reconstructive surgery of the mitral valve incompetence. Ten year appraisal. 1 Thorac Cardiovasc Surg 1980;79:338-48. 2. Gallerstein PE, Berger M, Rubenstein S, Berdoff RL, Goldberg E. Systolic anterior motion of the mitral valve and outflow obstruction after mitral valve reconstruction. Chest 1983;83:819-20. 3. Kronzon L Mercurio P, Winer HE, Colvin S. Noninvasive evaluation of mitral valvuloplasty. Am Heart 1 1983;106:362-8. 4. Carpentier A, Deloche A, Dauptain 1, et al. A new reconstructive operation for correction of mitral and tricuspid valve insufficiency. 1 Thorac Cardiovasc Surg 1971;61:1-13. 5. Termini BA, lackson PA, Williams CD. Systolic anterior motion of the mitral valve following annuloplasty. Vase Surg 1977;11:55-60. 6. Lindvall K, Herrlin B Mitral annulus calcification, systolic anterior motion of the antenor mitral leaflet and outflow obstruction m two patients without hypertrophic cardiomyopathy. Acta Med Scand 1981;209:513-8.