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The association of fixed and dynamic left ventricular outflow obstruction
The association of fixed and dynamic ventricular outflow obstruction
left
Kenneth R. Bloom, M.D., F.C.P.(SA.) Richard A. Meyer, M.D. Kevin E. Bove, M.D. Samuel Kaplan, M.D. Cincinnati,
Ohio
Fixed obstruction to the left ventricular outflow tract at valvular, subvalvular, or supravalvular levels, as well as coarctation of the aorta, may be complicated by an additional dynamic obstruction.‘T5 This is due to abnormal systolic anterior motion of the mitral leaflet causing additional narrowing of the left ventricular outflow tract.6J We have been able to predict preoperatively the presence or absence of complicating dynamic obstruction by echocardiography. Materials
and mbthods
Twelve children ranging in age from six to 18 years were evaluated because of clinical signs of severe aortic valvular or subvalvular stenosis. Eleven children were studied by echocardiography, cardiac catheterization, and angiocardiography. One patient did not undergo catheterization because of a bleeding disorder. Patients were studied under basal conditions in the supine position, and the effects of pharmacologic agents on the left ventricular outflow tract were not studied. Echocardiographic examination was carried out with a Hoffrel ultrasdnoscope, Model 101. A 2.25 MHz. transducer focused at 5 cm. or a 3.5 MHz. unfocused transducer was used. The echocardiograms were recorded both on Polaroid film and on a strip-chart recorder running at 50 or 75 From the Department of Pediatrics, University of Cincinnati, College of Medicine, Cincinnati. Supported in part by the UnitedStates Public Health Service Training Grant No. 3 TO1 HL05728 and the American Heart Association, Southwestern Ohio Chapter. Received for publication July 2, 1974. Reprint requests: Dr. R. A. Meyer, Children’s Hospital, Cincinnati, Ohio 45229.
588
mm. per second. The transducer was placed in the fourth left interspace within one inch of the left sternal border, and the mitral valve echo identified. This was scanned in its full extent through the left ventricular cavity by rotating the transducer from inferolateral to superomedial positions. The right and left septal surfaces with left ventricular endocardium were obtained by rotating the transducer laterally from the mitral valve echo. Near gain was adjusted until the right septal surface was clearly visualized.8 Results In all children, severe obstruction to the left ventricular outflow tract requiring surgical relief was identified. Valvular obstruction was present in seven, and four children had a discrete subvalvular membrane. The one patient who could not be catheterized had clinical signs of tight valvular aortic stenosis. All patients had symmetrical left ventricular and septal hypertrophy. Ten patients had normal anterior mitral valve leaflet motion in systole. Two patients had abnormal anterior systolic motion of the anterior mitral valve leaflet (Figs. i, A and 2, A). One child, nine years old, had valvular stenosis and one, ten years old, had a discrete subvalvular membrane. The ratio of the thickness of their left ventricular walls to their septa was 1:l and l.l:l, respectively. The degree of left ventricular hypertrophy was marked; the thicknesses being 1.9 and 1.6 cm., respectively. All children underwent open-heart surgery. Following relief of the fixed obstruction in the 10 cases with normal mitral valve motion a residual gradient of no greater than 20 mm. Hg was
May, 1975, Vol. 89, No. 5, pp. 586-590
Fixed and dynamic
left ventricular
outflow obstruction
Fig. 1. A, a g-year-old child with valvular stenosis and abnormal systolic anterior motion of the anterior mitral valve leaflet (arrow.) B, postoperative echogram shows minimal residual abnormal systolic motion (arrow). The left ventricular outflow tract does not appear as narrow. LV, left ventricle; RVED, right ventricular end-diastolic dimension; and SAM, systolic anterior motion.
found. This gradient was measured during surgery after the patient had come off cardiopulmonary bypass. One of the patients with systolic anterior motion had an intraoperative gradient of 125 mm. Hg across the left ventricular outflow tract after aortic valvotomy. A septal myotomy reduced the gradient to 20 mm. Hg. The other child with systolic anterior motion had a discrete thick fibrous membrane resected from the subvalvular area. In addition, the left ventricular outflow tract was so narrowed that a septal myotomy was performed. A preoperative gradient of 235 mm. Hg was completely abolished by the two procedures. In both these patients the mitral valve motion returned to normal or near normal in the postoperative period (Figs. 1, B and 2, B). Histologic examination of the resected portions of the septum showed hypertrophy of normally oriented muscle fibers (Fig. 3, A). In addition, the patient who had the discrete subvalvular membrane showed multiple small areas of fibrosis. A histologic preparation from the septum of a patient with idiopathic hypertrophic subaortic stenosis is shown for comparison (Fig. 3, El). Discussion
There are now at least 29 reported cases of the association of fixed left ventricular outflow tract obstruction with dynamic subvalvular obstruc-
American
Heart Journal
tion.1-5 Most authors have suggested that these cases represent the chance occurrence of two separate diseases; namely, the fixed obstruction and idiopathic hypertrophic subaortic stenosis. In our two patients this appeared unlikely for the following reasons: (1) the hypertrophy of the left ventricular wall and septum was symmetrical. Asymmetrical septal hypertrophy is an essential finding for the diagnosis of idiopathic hypertrophic subaortic stenosis.8-1o (2) The histology of the resected portion of ventricular septum showed hypertrophy of normally arranged muscle fibers. The disorientation usually seen in asymmetric septal hypertrophy was not present (Figs. 3, A and B). (3) Dynamic obstruction to the left ventricular outflow tract is very rarely reported in association with congenital heart disease other than fixed left ventricular outflow tract obstruction or coarctation of the aorta.‘lJ2 This frequent association with only these forms of congenital heart disease suggests a causal rather than a chance relationship. The echocardiographic finding of abnormal systolic anterior motion of the mitral valve has previously been regarded as diagnostic of the disease entity of asymmetric septal hypertrophyS7J3 However, it may be that it is specific only for a mechanism of left ventricular outflow tract obstruction which is related to severe symmetric hypertrophy. Asymmetric septal hypertrophy
587
Bloom
et al.
Fig. 2. A, a lo-year-old child anterior mitral valve leaflet systolic anterior motion.
with a discrete subvalvular (arrow). B, postoperative
would also be required before the diagnosis of asymmetrical muscular (dynamic) subvalvular obstruction could be made. It is possible that in some instances the presence of a constant afterload on the left ventricle from birth results in the exuberant concentric hypertrophy seen in these cases. The left ventricular outflow tract is, therefore, narrowed. The massive hypertrophy of the papillary muscles and the commonly associated fibrosis of them14 may then result in their dysfunction leading to abnormal mitral valve leaflet motion with further obstruction to the narrowed left ventricular outflow tract. Relief of fixed obstruction, especially to right ventricular outflow, has been reported to result in a gradual reduction of the residual gradient.‘J6 This, however, may not occur on the left side, and a significant residual gradient with symptoms may persist for years after relief of the fixed obstruction.1-3This fact has been stated by some authors as an argument toward the co-existence of two separate diseases,3J6 namely, fixed left ventricular outflow obstruction and idiopathic
588
membrane and abnormal systolic anterior echogram shows near normal mitral valve
motion motion.
of the SAM,
hypertrophic subaortic stenosis. Persistent postoperative dynamic obstruction in the left ventricular outflow tract results in an afterload to the left ventricle which is a continuing stimulus to left ventricular hypertrophy and, hence, abnormal systolic anterior motion of the mitral valve. This then becomes a self perpetuating mechanism. The often marked residual left ventricular outflow tract obstruction may result in death in the immediate postoperative period.’ This possibility and also the persistence of a left ventricular outflow tract gradient with symptoms for many years emphasizes the need to recognize the co-existence of dynamic and fixed obstruction preoperatively. Our study has demonstrated that echocardiography enables one to accurately predict this. In addition, the resection of the subaortic portion of the septum results in normalization of the mitral valve echo. Summary
Twelve patients were investigated diographically and angiographically
echocarand were
May, 1975, Vol. 89, No. 5
Fixed and dynamic
Fig. 3. A, section from septum of the patient per-trophy of normally arranged longitudinally cell processes or of intracellular myofibrils
with discrete subvalvular oriented muscle fibers is apparent. Hematoxylin
membrane and dynamic is shown. No disorientation and eosin, X 530.
Fig. 3. B, section from the septum of a patient (not in this series) with classical stenosis with obstruction. The overall architectural disarray and disorientation rows) are both evident. Hematoxylin and eosin, X 500.
American
Heart Journal
left ventricular
outflow obstruction
obstruction. Hyof myocardial
idiopathic hypertrophic subaortic of intracellular myofibrils Car-
689
Bloom et al.
shown to have severe fixed obstruction to the left ventricular outflow tract. Eight had valvular stenosis, and four had discrete subvalvular membranes. Two of the patients had additional dynamic obstruction of the left ventricular outflow tract. This was recognized preoperatively by echocardiography because of abnormal systolic motion of the mitral leaflet. At the time of definitive surgery for relief of the fixed obstruction, the additional dynamic obstruction was identified and treated, since persistent residual obstruction may lead to death in the immediate postoperative period or to long-term symptoms. The dynamic left ventricular outflow obstruction is probably a result of the hypertrophy produced by the fixed obstruction. REFERENCES
Parker, D. P., Kaplan, M. A., and Connolly, J. E.: Co-existent aortic valvular and functional hypertrophic eubaortic stenosis, Am. J. Cardiol. 24307, 1969. Block, P. C., Powell, W. J., Dinsmore, R. E., and Goldblatt, A.: Co-existent fixed congenital and idiopathic hypertrophic subaortic stenosis, Am. J. Cardiol. 31:523, 1973. Chung, K. J., Manning, J. A., and Gramiak, R.: Echocardiography in co-existing hypertrophic subaortic stenosis and fixed left ventricular outflow obstruction, Circulation 49:673, 1974. Gordon, A. S.: The surgical management of congenital supravalvular, valvular, and subvalvular aortic stenosis using deep hypothermia, J. Thorac. Cardiovasc. Sorg. 43:141, 1962.
5.
6.
7. 8. 9. 10.
11. 12. 13. 14. 15.
16.
Reis, R. L., Peterson, L. M., Mason, D. T., et al.: Congenital fixed subvalvular aortic stenosis, Circulation 43:1, 1971. Shah, P., Gramiak, R., and Kramer, D. H.: Ultrasound localization of left ventricular outflow obstruction in hypertrophic obstructive cardiomyopathy, Circulation 4oI3, 1969. Popp, R. L., and Harrison, D. C.: Ultrasound in the diagnosis and evaluation of therapy of idiopathic hypertrophic subaortic stenosis, Circulation 40:905, 1969. Henry, W. L., Clark, C. E., and Epstein, S. E.: Asymmetric septal hypertrophy, Circulation 47:225, 1973. Roberts, W. C.: Valvular, subvalvular, and supravalvular aortic stenosis: morphologic features, Cardiovasc. Clin. 5104, 1973. Pathologic aspects of valvular and subvalvular (discrete and diffuse aortic stenosis. In: The Natural History and Progress in Treatment of Congenital Heart Defects, Kidd, B. S. L., and Keith, J. D., editors. Springfield, Ill., 1971, Charles C Thomas, pp. 221-224. Shem-Tov, A., Deutsch, V., Yahini, J. H., et al.: Cardiomyopathy associated with congenital heart disease, Br. Heart J. 33:782, 1971. Somerville, J., and McDonald, L.: Congenital anomalies in the heart with hypertrophic cardiomyopathy, Br. Heart J. 30:713, 1968. Feigenbaum, H.: Echocardiography. Philadelphia, 1972, Lea and Febiger, p. 63. Roberts, W. C., and Cohen, L. S.: Left ventricular papillary muscles, Circulation 46:138, 1972. Engle, M. A., Holswade, G. R., and Goldberg, H. P.: Regression after open valvotomy of infundibular stenosis accompanying severe valvular pulmonic stenosis, Circulation 179362, 1958. Champsaur, G., Trusler, G. A., and Mustard, W. T.: Congenital discrete subvalvular aortic stenosis. Surgical experience and long-term follow-up in 20 pediatric patients, Br. Heart J. 35:443, 1973. I
590
May, 1975, Vol. 89, No. 5
left
Kenneth R. Bloom, M.D., F.C.P.(SA.) Richard A. Meyer, M.D. Kevin E. Bove, M.D. Samuel Kaplan, M.D. Cincinnati,
Ohio
Fixed obstruction to the left ventricular outflow tract at valvular, subvalvular, or supravalvular levels, as well as coarctation of the aorta, may be complicated by an additional dynamic obstruction.‘T5 This is due to abnormal systolic anterior motion of the mitral leaflet causing additional narrowing of the left ventricular outflow tract.6J We have been able to predict preoperatively the presence or absence of complicating dynamic obstruction by echocardiography. Materials
and mbthods
Twelve children ranging in age from six to 18 years were evaluated because of clinical signs of severe aortic valvular or subvalvular stenosis. Eleven children were studied by echocardiography, cardiac catheterization, and angiocardiography. One patient did not undergo catheterization because of a bleeding disorder. Patients were studied under basal conditions in the supine position, and the effects of pharmacologic agents on the left ventricular outflow tract were not studied. Echocardiographic examination was carried out with a Hoffrel ultrasdnoscope, Model 101. A 2.25 MHz. transducer focused at 5 cm. or a 3.5 MHz. unfocused transducer was used. The echocardiograms were recorded both on Polaroid film and on a strip-chart recorder running at 50 or 75 From the Department of Pediatrics, University of Cincinnati, College of Medicine, Cincinnati. Supported in part by the UnitedStates Public Health Service Training Grant No. 3 TO1 HL05728 and the American Heart Association, Southwestern Ohio Chapter. Received for publication July 2, 1974. Reprint requests: Dr. R. A. Meyer, Children’s Hospital, Cincinnati, Ohio 45229.
588
mm. per second. The transducer was placed in the fourth left interspace within one inch of the left sternal border, and the mitral valve echo identified. This was scanned in its full extent through the left ventricular cavity by rotating the transducer from inferolateral to superomedial positions. The right and left septal surfaces with left ventricular endocardium were obtained by rotating the transducer laterally from the mitral valve echo. Near gain was adjusted until the right septal surface was clearly visualized.8 Results In all children, severe obstruction to the left ventricular outflow tract requiring surgical relief was identified. Valvular obstruction was present in seven, and four children had a discrete subvalvular membrane. The one patient who could not be catheterized had clinical signs of tight valvular aortic stenosis. All patients had symmetrical left ventricular and septal hypertrophy. Ten patients had normal anterior mitral valve leaflet motion in systole. Two patients had abnormal anterior systolic motion of the anterior mitral valve leaflet (Figs. i, A and 2, A). One child, nine years old, had valvular stenosis and one, ten years old, had a discrete subvalvular membrane. The ratio of the thickness of their left ventricular walls to their septa was 1:l and l.l:l, respectively. The degree of left ventricular hypertrophy was marked; the thicknesses being 1.9 and 1.6 cm., respectively. All children underwent open-heart surgery. Following relief of the fixed obstruction in the 10 cases with normal mitral valve motion a residual gradient of no greater than 20 mm. Hg was
May, 1975, Vol. 89, No. 5, pp. 586-590
Fixed and dynamic
left ventricular
outflow obstruction
Fig. 1. A, a g-year-old child with valvular stenosis and abnormal systolic anterior motion of the anterior mitral valve leaflet (arrow.) B, postoperative echogram shows minimal residual abnormal systolic motion (arrow). The left ventricular outflow tract does not appear as narrow. LV, left ventricle; RVED, right ventricular end-diastolic dimension; and SAM, systolic anterior motion.
found. This gradient was measured during surgery after the patient had come off cardiopulmonary bypass. One of the patients with systolic anterior motion had an intraoperative gradient of 125 mm. Hg across the left ventricular outflow tract after aortic valvotomy. A septal myotomy reduced the gradient to 20 mm. Hg. The other child with systolic anterior motion had a discrete thick fibrous membrane resected from the subvalvular area. In addition, the left ventricular outflow tract was so narrowed that a septal myotomy was performed. A preoperative gradient of 235 mm. Hg was completely abolished by the two procedures. In both these patients the mitral valve motion returned to normal or near normal in the postoperative period (Figs. 1, B and 2, B). Histologic examination of the resected portions of the septum showed hypertrophy of normally oriented muscle fibers (Fig. 3, A). In addition, the patient who had the discrete subvalvular membrane showed multiple small areas of fibrosis. A histologic preparation from the septum of a patient with idiopathic hypertrophic subaortic stenosis is shown for comparison (Fig. 3, El). Discussion
There are now at least 29 reported cases of the association of fixed left ventricular outflow tract obstruction with dynamic subvalvular obstruc-
American
Heart Journal
tion.1-5 Most authors have suggested that these cases represent the chance occurrence of two separate diseases; namely, the fixed obstruction and idiopathic hypertrophic subaortic stenosis. In our two patients this appeared unlikely for the following reasons: (1) the hypertrophy of the left ventricular wall and septum was symmetrical. Asymmetrical septal hypertrophy is an essential finding for the diagnosis of idiopathic hypertrophic subaortic stenosis.8-1o (2) The histology of the resected portion of ventricular septum showed hypertrophy of normally arranged muscle fibers. The disorientation usually seen in asymmetric septal hypertrophy was not present (Figs. 3, A and B). (3) Dynamic obstruction to the left ventricular outflow tract is very rarely reported in association with congenital heart disease other than fixed left ventricular outflow tract obstruction or coarctation of the aorta.‘lJ2 This frequent association with only these forms of congenital heart disease suggests a causal rather than a chance relationship. The echocardiographic finding of abnormal systolic anterior motion of the mitral valve has previously been regarded as diagnostic of the disease entity of asymmetric septal hypertrophyS7J3 However, it may be that it is specific only for a mechanism of left ventricular outflow tract obstruction which is related to severe symmetric hypertrophy. Asymmetric septal hypertrophy
587
Bloom
et al.
Fig. 2. A, a lo-year-old child anterior mitral valve leaflet systolic anterior motion.
with a discrete subvalvular (arrow). B, postoperative
would also be required before the diagnosis of asymmetrical muscular (dynamic) subvalvular obstruction could be made. It is possible that in some instances the presence of a constant afterload on the left ventricle from birth results in the exuberant concentric hypertrophy seen in these cases. The left ventricular outflow tract is, therefore, narrowed. The massive hypertrophy of the papillary muscles and the commonly associated fibrosis of them14 may then result in their dysfunction leading to abnormal mitral valve leaflet motion with further obstruction to the narrowed left ventricular outflow tract. Relief of fixed obstruction, especially to right ventricular outflow, has been reported to result in a gradual reduction of the residual gradient.‘J6 This, however, may not occur on the left side, and a significant residual gradient with symptoms may persist for years after relief of the fixed obstruction.1-3This fact has been stated by some authors as an argument toward the co-existence of two separate diseases,3J6 namely, fixed left ventricular outflow obstruction and idiopathic
588
membrane and abnormal systolic anterior echogram shows near normal mitral valve
motion motion.
of the SAM,
hypertrophic subaortic stenosis. Persistent postoperative dynamic obstruction in the left ventricular outflow tract results in an afterload to the left ventricle which is a continuing stimulus to left ventricular hypertrophy and, hence, abnormal systolic anterior motion of the mitral valve. This then becomes a self perpetuating mechanism. The often marked residual left ventricular outflow tract obstruction may result in death in the immediate postoperative period.’ This possibility and also the persistence of a left ventricular outflow tract gradient with symptoms for many years emphasizes the need to recognize the co-existence of dynamic and fixed obstruction preoperatively. Our study has demonstrated that echocardiography enables one to accurately predict this. In addition, the resection of the subaortic portion of the septum results in normalization of the mitral valve echo. Summary
Twelve patients were investigated diographically and angiographically
echocarand were
May, 1975, Vol. 89, No. 5
Fixed and dynamic
Fig. 3. A, section from septum of the patient per-trophy of normally arranged longitudinally cell processes or of intracellular myofibrils
with discrete subvalvular oriented muscle fibers is apparent. Hematoxylin
membrane and dynamic is shown. No disorientation and eosin, X 530.
Fig. 3. B, section from the septum of a patient (not in this series) with classical stenosis with obstruction. The overall architectural disarray and disorientation rows) are both evident. Hematoxylin and eosin, X 500.
American
Heart Journal
left ventricular
outflow obstruction
obstruction. Hyof myocardial
idiopathic hypertrophic subaortic of intracellular myofibrils Car-
689
Bloom et al.
shown to have severe fixed obstruction to the left ventricular outflow tract. Eight had valvular stenosis, and four had discrete subvalvular membranes. Two of the patients had additional dynamic obstruction of the left ventricular outflow tract. This was recognized preoperatively by echocardiography because of abnormal systolic motion of the mitral leaflet. At the time of definitive surgery for relief of the fixed obstruction, the additional dynamic obstruction was identified and treated, since persistent residual obstruction may lead to death in the immediate postoperative period or to long-term symptoms. The dynamic left ventricular outflow obstruction is probably a result of the hypertrophy produced by the fixed obstruction. REFERENCES
Parker, D. P., Kaplan, M. A., and Connolly, J. E.: Co-existent aortic valvular and functional hypertrophic eubaortic stenosis, Am. J. Cardiol. 24307, 1969. Block, P. C., Powell, W. J., Dinsmore, R. E., and Goldblatt, A.: Co-existent fixed congenital and idiopathic hypertrophic subaortic stenosis, Am. J. Cardiol. 31:523, 1973. Chung, K. J., Manning, J. A., and Gramiak, R.: Echocardiography in co-existing hypertrophic subaortic stenosis and fixed left ventricular outflow obstruction, Circulation 49:673, 1974. Gordon, A. S.: The surgical management of congenital supravalvular, valvular, and subvalvular aortic stenosis using deep hypothermia, J. Thorac. Cardiovasc. Sorg. 43:141, 1962.
5.
6.
7. 8. 9. 10.
11. 12. 13. 14. 15.
16.
Reis, R. L., Peterson, L. M., Mason, D. T., et al.: Congenital fixed subvalvular aortic stenosis, Circulation 43:1, 1971. Shah, P., Gramiak, R., and Kramer, D. H.: Ultrasound localization of left ventricular outflow obstruction in hypertrophic obstructive cardiomyopathy, Circulation 4oI3, 1969. Popp, R. L., and Harrison, D. C.: Ultrasound in the diagnosis and evaluation of therapy of idiopathic hypertrophic subaortic stenosis, Circulation 40:905, 1969. Henry, W. L., Clark, C. E., and Epstein, S. E.: Asymmetric septal hypertrophy, Circulation 47:225, 1973. Roberts, W. C.: Valvular, subvalvular, and supravalvular aortic stenosis: morphologic features, Cardiovasc. Clin. 5104, 1973. Pathologic aspects of valvular and subvalvular (discrete and diffuse aortic stenosis. In: The Natural History and Progress in Treatment of Congenital Heart Defects, Kidd, B. S. L., and Keith, J. D., editors. Springfield, Ill., 1971, Charles C Thomas, pp. 221-224. Shem-Tov, A., Deutsch, V., Yahini, J. H., et al.: Cardiomyopathy associated with congenital heart disease, Br. Heart J. 33:782, 1971. Somerville, J., and McDonald, L.: Congenital anomalies in the heart with hypertrophic cardiomyopathy, Br. Heart J. 30:713, 1968. Feigenbaum, H.: Echocardiography. Philadelphia, 1972, Lea and Febiger, p. 63. Roberts, W. C., and Cohen, L. S.: Left ventricular papillary muscles, Circulation 46:138, 1972. Engle, M. A., Holswade, G. R., and Goldberg, H. P.: Regression after open valvotomy of infundibular stenosis accompanying severe valvular pulmonic stenosis, Circulation 179362, 1958. Champsaur, G., Trusler, G. A., and Mustard, W. T.: Congenital discrete subvalvular aortic stenosis. Surgical experience and long-term follow-up in 20 pediatric patients, Br. Heart J. 35:443, 1973. I
590
May, 1975, Vol. 89, No. 5