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The pathologist approaches clinical coronary disease
CURRENT TOPICS Turn-around time: Length of time passed between submission of queries and receipt of retrieval print-out.
References 1. Systematized Nomenclature of Pathology. Chicago, College of American Pathologists, 1965. 2. Pratt, A. W., and Thomas, L. B.: An information processing system for pathology data. In: Sommers, S. C. (Editor): Pathology Annual. 1966. New York, Appleton-Century-Crofts, 1966, pp. 1-21. 3. Crocker, D. W.: Preparation of anatomic pathology data for automation, In Sommers, S. C. (Editor): Pathology Annual. 1969. New York, AppletonCentury-Crofts, 1969, pp. 31-41. 4. Pribor, H. D., Shuster, M., and Dickson, W.: Anatomic and cytology pathology data processing with a small digital computer. Seminar on Data Processing and SNOP, Annual Meeting, College of American Pathologists, Chicago, 1969. 5. Pathology Natural Language Retrieval System (PANLARS) and Clinico-Pathological Statistical Retrieval System (CLIPSTARS). Monograph. Washington, D.C., Armed Forces Institute of Pathology, ComputerServices Division, 1971. 6. Thompson, E. T., and Hayden, A. D. (Editors): Standard Nomenclature of Diseases and Operations. Ed. 5. New York, The Blakiston Division, McGrawHiIl Book Company, 1961. 7. Smith, J. C., and Melton, J.: Manipulation of autopsy diagnoses by computer technique. J.A.M.A., 188: 958, 1964. 8. Smith, J. C., and Melton, J.: Data Control for Anatomic Pathology. Cleveland, Western Reserve University Instituteof Pathology, 1965. 9. Lamson, B. G.: Data Processing in a Medical Center: Progress Report. Los Angeles, University of California, 1966. 10. Lamson, B, G., and Dimsdale, n.: A natural language information retrieval system. IEEE Proc., 54:1636, 1966. 11. Paplanus, S. H., Shepard, R. H., and Zvargulis, J. E.: A computer-based system for autopsy diagnosis, storage and retrieval without numerical coding. Lab. Invest., 20:139,1969.
12. Clinical Laboratories Improvement Act of 1967, Public Law 90-174, §353. 13. Wied, G. L., McGrew, E. A., and Rosenthal, E.: A cytologic registry and computer system for a city-wide cooperative screening project. Acta Cytol., I1: 1.50, 1967. 14. Wied, G. L.: Quality control mechanisms for cytology programs. Editorial. Acta Cytol., 9:407, 1965. 15. Collins, D. N., Kaufmann, W., and Albrecht, R.: New York State proficiency testing program in exfoliative cytology: Evaluation. Acta Cytol., 15:468, 1971. Temple University Hospital 3401 N. Broad Street Philadelphia, Pennsylvania 19140
THE PATHOLOGIST APPROACHES CLINICAL CORONARY DISEASE* ZEEV VLODAVER, JESSE
E.
M.D.,t and M.D.*
EDWARDS,
The surgical treatment of coronary atherosclerosis with vein grafts has brought a num-
bel' of questions into focus for the pathologist, some related to the evaluation of these grafts and others to the correlation of postmortem findings with those of angiocardiography. It is appropriate to discuss the contributions that can be made by the pathologist in this complex and important area. The vital question with regard to vein bypass grafting is the fate of the graft and the coronary arterial system in relation to it. A major obstacle to the evaluation of the long range state of grafts is the difficulty in securing material for pathologic examination. This may be attributable in part to the frequent success of the procedure, but a more important factor is the demise of many patients in communities distant from cardiac surgery centers. The surgeons who perform this procedure and the pathologists associated with them should make every effort to obtain specimens from patients who succumb regardless of the location of death.
CORRELATION OF SURGICAL PROCEDURES WITH PATHOLOGIC FINDINGS Given a specimen in which a graft has been placed, the pathologist should secure the information obtained by angiocardiographic examination and regarding the surgical procedure, both being necessary for correlation with observations to be made on the specimen. In his examination the pathologist will be concentrating his attention on the state of the aortic and arterial anastomoses, the graft, and the coronary artery proximal and distal to the graft. The aortic ostium of the graft may be occluded as a result of torsion of the graft, faulty surgical technique, or thrombosis. At the level of the arterial anastomosis, stenosis may result from thrombosis, improper suturing, or a segmental narrowing of the artery. It is preferable to make multiple cross sections of the graft to determine the state of its lumen. A longitudinal opening makes the interpretation less secure and results in more distortion in the histologic sections. *This study was supported by Public Health Service Research Grant 5 ROI HE05694 and Research Training Grant 5 TOl HE05570 from the National Heart Institute. tSenior Research Associate in Cardiovascular Pathology. Department of Pathology, Charles T. Miller Hospital, St. Paul, Minnesota. Cardiologist, Chaim Sheba Medical Institute, Tel Hashomer, Israel (on leave of absence). tProfessor of Pathology, The University of Minnesota Medical School, Minneapolis. Director of Laboratories, Charles T. Miller Hospital, St. Paul, Minnesota.
3
HUMAN PATHOLOGY - VOLUME 3, NUMBER l-i\!larch 1972
, \
,·.1": ,.:,. I
.
~
(.
,
:1"
~~,~~~~~~~~- " L
:~ . ' J ./
Figure 1. Photomicrographs of segments of saphenous vein grafts obtained prior to insertion. (t, A normal saphenous vein. (Elastic tissue stain. x 17.) band c, A vein with intimal fibrous thickening. b, The intima is thickened by relatively acellular collagenous tissue. (Elastic tissue stain. x 17.) C, Higher power view of portion of b. The intima (1) is thickened by relatively acellular collagenous tissue (Hematoxylin and eosin stain. x60.) d, Saphenous vein that had functioned as a graft for nine months. The intima is greatly thickened by cellular fibrous tissue, appearing dark because of the presence of acid rnucopolysaccharides. (Stain for acid mucopolysaccharides. x 14.)
4
On microscopic examination the graft may be found to be normal, to have fibrous intimal thickening of remote or recent onset, or to contain thrombi. The normal saphenous vein has a thin intima containing few cells. Fibrous intimal thickening may have been present in the vein prior to grafting; evaluation of this possibility requires comparison with a control section from at least one end of the graft before its insertion (Fig. la to c). In some grafts that have been functioning for a long period of time; acquired intimal changes appear in the form of cellular fibrous proliferation, which may almost totally obliterate the lumen (Fig.
ld). Such lesions are devoid of fat and show a high content of acid rnucopolysaccharides.' The term "arterialization" has been used for this change, but is inappropriate since the altered graft has no structural similarity to an artery and its media retains the pattern of venous media. The intimal lesion is considered a reaction to arterial pressure and flow. When thrombi have been observed, their age has appeared to correspond with the postoperative time interval, suggesting that they developed shortly after the operation. Obstructive lesions are often present in the artery distal to a graft. The frequency
CURRENT TO P ICS with whi ch these lesions are observed by th e path ologist probably reflects a factor of selec tion , because d ista l arterial obstruction obvious ly increases the mortali ty. These lesions are usually atherosclerotic an d are most commonly observed in the right coronary artery. Two fa ctors may be involved in this site of predilection . I n the first place the d istrib u tion of at herosclerotic lesions in the right coronary arte ry differs from that in the an terior descen d in g coronary artery. In the right co ronary a rtery the lesions do not typically decrease in severity as o n e proceeds down the vessel. In o ur experien ce th e most com m o n site of an obs tru ctive atheroma in the coro n ar y syste m is the segment of th e right coronary artery lying between its marginal and posterior descending branches. Secondly, in arteriograms this seg-
Figure 2.
me nt is often obscured by th e diaphragm so th at the surgeon does not anticipate lesio ns that are in fact present. T he existe n ce of obstructive lesions distal to th e e ntr an ce o f th e graft may enhance the tendencie s for thrombosis and fibrous pro liferation to occur within the graft itself, Limited ex perience wit h grafts that h a ve been functioning for a lon g' period of ti me suggests th at the forceful stream of b lood entering the arte ry th ro ugh t he graft may be responsible for a reactive or j e t lesion in the arte ry. T his may beco m e large eno ugh to cause obstructio n as a late mani festatio n after a p revious ly exi sting u n obstru cted flow (Fig. 2). The possibility of jet lesions favors the p lacement of the graft at th e smallest possible an gle to the long axis of the artery. It is logica l to
Phoromlcrographs of a coro-
nary arte ry jus t distal to a functionin g graft three and one-half yea rs after its placement. a, In this view of the entire artery there is marked eccentric intimal thickening by cellular connective tissue. (Hemato xylin and eosin stain. x 17.) b, Higher power view revealing cellularity of thickened intima. (Hematoxylin and eosin stain. X 2l0 .)
5
HUMAN PATHOLOGY-VOLUME 3, NUMBER l-A'larch 1972 The segment of artery proximal to the graft anastomosis is of particular interest. This segment takes the form of a cul-de-sac lying between the ostium of the graft distally and the most distal obstructive arterial lesion proximally. The longer this segment, the greater the amount of static blood (Fig. 4). Its presence favors thrombosis, which may in turn be the basis for embolism to distal segments of the involved artery. The length of this segment should be measured and sections should be obtained for microscopic examination. CORRELATION OF ANGlO CARDIOGRAMS WITH PATHOLOGIC FINDINGS
b Figure 3. Diagrammatic portrayal of the differing angles between the graft and the comnary anery. In a the angle is almost 90 degrees, and the stream of blood flowing through the graft strikes the intima opposite the anastomosis and may cause reactive changes. In b the graft is almost parallel to the artery, and the energy of the entering stream of blood is dispersed down the lumen rather than against the intima. assume that the more the graft approaches a right angle with the artery, the more likely the blood stream is to generate an obstructive reactive lesion (Fig. 3).
a.
6
b.
Figure 4. Diagrammatic portrayal of different levels of insertion of a vein graft with respect to the most distal obstructive arterial lesion. In a there is a long distance creating a cul-de-sac in the artery between the entrance of the graft, distally, and the obstructive arterial lesion, proximally. In b the insertion is theoretically ideal with the graft placed close to the most distal obstructive lesion; a very short or no culde-sac exists between the graft and the obstructive lesion.
Both the clinician and the radiologist are interested in knowing the pathologic findings that relate to the coronary arteriogram and to studies of left ventricular function. In order to correlate the arteriographic and pathologic findings in the coronary arteries it is desirable for the pathologist and the radiologist to work together; The pathologist should remove sufficient epicardial fat to allow easy observation of the arteries and their branches. The branches seen in the specimen should then be compared to those visible on the arteriogram. The radiologist identifies sites of apparent obstruction, and cross sections of the coronary tree are made by the pathologist for the purpose of correlation. The obstructions should be graded in a manner that is meaningful to both the radiologist and the pathologist. It is particularly important to take sections of segments interpreted differently on the basis of arteriographic and pathologic examinations. Usually the disagreement is in the direction of the radiologist's underestimating the degree of obstruction. Preliminary studies in our laboratory indicate that one factor in the radiologist's missing an obstructive lesion relates to the shape of the narrowed lumen. For this reason we have classified coronary luminal narrowing into three categories: (a) central, (b) eccentric slit-like, and (c) eccentric polymorphous (Fig. 5).2 The eccentric slit-like lumen, although severly narrowed, has one dimension nearly as wide as the original lumen. The eccentric polymorphous lumen may be circular or angulated. OUT experience suggests that the incidence of the eccentric slit-like lumen is unusually high when there is disagreement between the arteriogram and the pathologic examination. The apparent reason for this is that in certain arteriographic projections, the lumen may appear to be of normal width when it is in fact severely narrowed. Physiologic and angiocarcliographic investigations of left ventricular function should be correlated with pathologic findings. Of
CURRENT TOPICS
Figure 5. Three types of lumens seen in obstructive atherosclerosis. a, Central and circular lumen. (Elastic tissue stain. x 15.) b, Eccentric and polymorphous lumen. (Elastic tissue stain. X 13). c, Eccentric and slitlike lumen. (Elastic tissue stain. x 13.)
7
HUMAN PATHOLOGY-VOLUME 3, NUMBER i
-s
Marct: 1972
Figure 6. Healed subendocardial myocardial infarction in the inferoseptal area of the basal portion of the left ventricle. The adjacent posteromedial papillary muscle is also scarred. The remaining part of the infarct, the medial edge of which is outlined by arrows, is partly overhung by the posterior lea net of the mitral valve and may be overlooked. Hollowing of the left ventricular cavity is suggestive of the presence of such an infarct.
special interest are segments of the left ventricle that either fail to contract or contract asynchronously with the remainder of the wall. Usually such segments are the site of healed infarction, It is important to emphasize that certain healed subendocardial infarcts may escape attention, especially when the heart has been opened in the standard fashion rather
than cut into a series of cross sections. This is particularly true of infarcts at the junction of the ventricular septum and the diaphragmatic aspect of the left ventricle at its base (Fig. 6). This area is overhung by the posterior leaflet of the mitral valve. From the endocardial view the site of the lesion may be marked by a shallow depression with slight endocardial thickening.
Slice I. (apex)
8
Figure 7. Diagram of cross sections of ventricular portion of heart viewed from above. Shaded areas indicate zones that may be sectioned to "spot check" the myocardium in the distribution of each of the three coronary arteries.
CURRENT TOPICS Even on cross sectioning an infarct in this region may be overlooked because of the small amount of scar tissue present. Any questionable gross alteration requires a section for its elucidation. In general, sections of myocardium for histologic studies are taken from areas with obvious gross lesions. However, in all cases of coronary arterial disease, whether or not the patient has had an operation, at least three spot-check sections should be taken, one from the area of distribution of each of the coro-
nary arteries (Fig. 7). This type of examination may disclose early changes of acute myocardial infarction that are invisible on gross inspection. References 1. Vlodaver , 2., and Edwards, J. E.: Pathologic changes in aortic-coronary arrerial saphenous vein grafts. Circulation, 44:719, 1971. 2. Vlodaver, A., and Edwards, J. E.: Pathology of coronary atherosclerosis. I'rog. Carrliov, Dis" /4:256, 1971.
Department of Pat!1ology Charles T. Miller Hospital 125 West College Avenue St. Paul, Minnesota 55 J 02 (Dr. Edwards)
9
References 1. Systematized Nomenclature of Pathology. Chicago, College of American Pathologists, 1965. 2. Pratt, A. W., and Thomas, L. B.: An information processing system for pathology data. In: Sommers, S. C. (Editor): Pathology Annual. 1966. New York, Appleton-Century-Crofts, 1966, pp. 1-21. 3. Crocker, D. W.: Preparation of anatomic pathology data for automation, In Sommers, S. C. (Editor): Pathology Annual. 1969. New York, AppletonCentury-Crofts, 1969, pp. 31-41. 4. Pribor, H. D., Shuster, M., and Dickson, W.: Anatomic and cytology pathology data processing with a small digital computer. Seminar on Data Processing and SNOP, Annual Meeting, College of American Pathologists, Chicago, 1969. 5. Pathology Natural Language Retrieval System (PANLARS) and Clinico-Pathological Statistical Retrieval System (CLIPSTARS). Monograph. Washington, D.C., Armed Forces Institute of Pathology, ComputerServices Division, 1971. 6. Thompson, E. T., and Hayden, A. D. (Editors): Standard Nomenclature of Diseases and Operations. Ed. 5. New York, The Blakiston Division, McGrawHiIl Book Company, 1961. 7. Smith, J. C., and Melton, J.: Manipulation of autopsy diagnoses by computer technique. J.A.M.A., 188: 958, 1964. 8. Smith, J. C., and Melton, J.: Data Control for Anatomic Pathology. Cleveland, Western Reserve University Instituteof Pathology, 1965. 9. Lamson, B. G.: Data Processing in a Medical Center: Progress Report. Los Angeles, University of California, 1966. 10. Lamson, B, G., and Dimsdale, n.: A natural language information retrieval system. IEEE Proc., 54:1636, 1966. 11. Paplanus, S. H., Shepard, R. H., and Zvargulis, J. E.: A computer-based system for autopsy diagnosis, storage and retrieval without numerical coding. Lab. Invest., 20:139,1969.
12. Clinical Laboratories Improvement Act of 1967, Public Law 90-174, §353. 13. Wied, G. L., McGrew, E. A., and Rosenthal, E.: A cytologic registry and computer system for a city-wide cooperative screening project. Acta Cytol., I1: 1.50, 1967. 14. Wied, G. L.: Quality control mechanisms for cytology programs. Editorial. Acta Cytol., 9:407, 1965. 15. Collins, D. N., Kaufmann, W., and Albrecht, R.: New York State proficiency testing program in exfoliative cytology: Evaluation. Acta Cytol., 15:468, 1971. Temple University Hospital 3401 N. Broad Street Philadelphia, Pennsylvania 19140
THE PATHOLOGIST APPROACHES CLINICAL CORONARY DISEASE* ZEEV VLODAVER, JESSE
E.
M.D.,t and M.D.*
EDWARDS,
The surgical treatment of coronary atherosclerosis with vein grafts has brought a num-
bel' of questions into focus for the pathologist, some related to the evaluation of these grafts and others to the correlation of postmortem findings with those of angiocardiography. It is appropriate to discuss the contributions that can be made by the pathologist in this complex and important area. The vital question with regard to vein bypass grafting is the fate of the graft and the coronary arterial system in relation to it. A major obstacle to the evaluation of the long range state of grafts is the difficulty in securing material for pathologic examination. This may be attributable in part to the frequent success of the procedure, but a more important factor is the demise of many patients in communities distant from cardiac surgery centers. The surgeons who perform this procedure and the pathologists associated with them should make every effort to obtain specimens from patients who succumb regardless of the location of death.
CORRELATION OF SURGICAL PROCEDURES WITH PATHOLOGIC FINDINGS Given a specimen in which a graft has been placed, the pathologist should secure the information obtained by angiocardiographic examination and regarding the surgical procedure, both being necessary for correlation with observations to be made on the specimen. In his examination the pathologist will be concentrating his attention on the state of the aortic and arterial anastomoses, the graft, and the coronary artery proximal and distal to the graft. The aortic ostium of the graft may be occluded as a result of torsion of the graft, faulty surgical technique, or thrombosis. At the level of the arterial anastomosis, stenosis may result from thrombosis, improper suturing, or a segmental narrowing of the artery. It is preferable to make multiple cross sections of the graft to determine the state of its lumen. A longitudinal opening makes the interpretation less secure and results in more distortion in the histologic sections. *This study was supported by Public Health Service Research Grant 5 ROI HE05694 and Research Training Grant 5 TOl HE05570 from the National Heart Institute. tSenior Research Associate in Cardiovascular Pathology. Department of Pathology, Charles T. Miller Hospital, St. Paul, Minnesota. Cardiologist, Chaim Sheba Medical Institute, Tel Hashomer, Israel (on leave of absence). tProfessor of Pathology, The University of Minnesota Medical School, Minneapolis. Director of Laboratories, Charles T. Miller Hospital, St. Paul, Minnesota.
3
HUMAN PATHOLOGY - VOLUME 3, NUMBER l-i\!larch 1972
, \
,·.1": ,.:,. I
.
~
(.
,
:1"
~~,~~~~~~~~- " L
:~ . ' J ./
Figure 1. Photomicrographs of segments of saphenous vein grafts obtained prior to insertion. (t, A normal saphenous vein. (Elastic tissue stain. x 17.) band c, A vein with intimal fibrous thickening. b, The intima is thickened by relatively acellular collagenous tissue. (Elastic tissue stain. x 17.) C, Higher power view of portion of b. The intima (1) is thickened by relatively acellular collagenous tissue (Hematoxylin and eosin stain. x60.) d, Saphenous vein that had functioned as a graft for nine months. The intima is greatly thickened by cellular fibrous tissue, appearing dark because of the presence of acid rnucopolysaccharides. (Stain for acid mucopolysaccharides. x 14.)
4
On microscopic examination the graft may be found to be normal, to have fibrous intimal thickening of remote or recent onset, or to contain thrombi. The normal saphenous vein has a thin intima containing few cells. Fibrous intimal thickening may have been present in the vein prior to grafting; evaluation of this possibility requires comparison with a control section from at least one end of the graft before its insertion (Fig. la to c). In some grafts that have been functioning for a long period of time; acquired intimal changes appear in the form of cellular fibrous proliferation, which may almost totally obliterate the lumen (Fig.
ld). Such lesions are devoid of fat and show a high content of acid rnucopolysaccharides.' The term "arterialization" has been used for this change, but is inappropriate since the altered graft has no structural similarity to an artery and its media retains the pattern of venous media. The intimal lesion is considered a reaction to arterial pressure and flow. When thrombi have been observed, their age has appeared to correspond with the postoperative time interval, suggesting that they developed shortly after the operation. Obstructive lesions are often present in the artery distal to a graft. The frequency
CURRENT TO P ICS with whi ch these lesions are observed by th e path ologist probably reflects a factor of selec tion , because d ista l arterial obstruction obvious ly increases the mortali ty. These lesions are usually atherosclerotic an d are most commonly observed in the right coronary artery. Two fa ctors may be involved in this site of predilection . I n the first place the d istrib u tion of at herosclerotic lesions in the right coronary arte ry differs from that in the an terior descen d in g coronary artery. In the right co ronary a rtery the lesions do not typically decrease in severity as o n e proceeds down the vessel. In o ur experien ce th e most com m o n site of an obs tru ctive atheroma in the coro n ar y syste m is the segment of th e right coronary artery lying between its marginal and posterior descending branches. Secondly, in arteriograms this seg-
Figure 2.
me nt is often obscured by th e diaphragm so th at the surgeon does not anticipate lesio ns that are in fact present. T he existe n ce of obstructive lesions distal to th e e ntr an ce o f th e graft may enhance the tendencie s for thrombosis and fibrous pro liferation to occur within the graft itself, Limited ex perience wit h grafts that h a ve been functioning for a lon g' period of ti me suggests th at the forceful stream of b lood entering the arte ry th ro ugh t he graft may be responsible for a reactive or j e t lesion in the arte ry. T his may beco m e large eno ugh to cause obstructio n as a late mani festatio n after a p revious ly exi sting u n obstru cted flow (Fig. 2). The possibility of jet lesions favors the p lacement of the graft at th e smallest possible an gle to the long axis of the artery. It is logica l to
Phoromlcrographs of a coro-
nary arte ry jus t distal to a functionin g graft three and one-half yea rs after its placement. a, In this view of the entire artery there is marked eccentric intimal thickening by cellular connective tissue. (Hemato xylin and eosin stain. x 17.) b, Higher power view revealing cellularity of thickened intima. (Hematoxylin and eosin stain. X 2l0 .)
5
HUMAN PATHOLOGY-VOLUME 3, NUMBER l-A'larch 1972 The segment of artery proximal to the graft anastomosis is of particular interest. This segment takes the form of a cul-de-sac lying between the ostium of the graft distally and the most distal obstructive arterial lesion proximally. The longer this segment, the greater the amount of static blood (Fig. 4). Its presence favors thrombosis, which may in turn be the basis for embolism to distal segments of the involved artery. The length of this segment should be measured and sections should be obtained for microscopic examination. CORRELATION OF ANGlO CARDIOGRAMS WITH PATHOLOGIC FINDINGS
b Figure 3. Diagrammatic portrayal of the differing angles between the graft and the comnary anery. In a the angle is almost 90 degrees, and the stream of blood flowing through the graft strikes the intima opposite the anastomosis and may cause reactive changes. In b the graft is almost parallel to the artery, and the energy of the entering stream of blood is dispersed down the lumen rather than against the intima. assume that the more the graft approaches a right angle with the artery, the more likely the blood stream is to generate an obstructive reactive lesion (Fig. 3).
a.
6
b.
Figure 4. Diagrammatic portrayal of different levels of insertion of a vein graft with respect to the most distal obstructive arterial lesion. In a there is a long distance creating a cul-de-sac in the artery between the entrance of the graft, distally, and the obstructive arterial lesion, proximally. In b the insertion is theoretically ideal with the graft placed close to the most distal obstructive lesion; a very short or no culde-sac exists between the graft and the obstructive lesion.
Both the clinician and the radiologist are interested in knowing the pathologic findings that relate to the coronary arteriogram and to studies of left ventricular function. In order to correlate the arteriographic and pathologic findings in the coronary arteries it is desirable for the pathologist and the radiologist to work together; The pathologist should remove sufficient epicardial fat to allow easy observation of the arteries and their branches. The branches seen in the specimen should then be compared to those visible on the arteriogram. The radiologist identifies sites of apparent obstruction, and cross sections of the coronary tree are made by the pathologist for the purpose of correlation. The obstructions should be graded in a manner that is meaningful to both the radiologist and the pathologist. It is particularly important to take sections of segments interpreted differently on the basis of arteriographic and pathologic examinations. Usually the disagreement is in the direction of the radiologist's underestimating the degree of obstruction. Preliminary studies in our laboratory indicate that one factor in the radiologist's missing an obstructive lesion relates to the shape of the narrowed lumen. For this reason we have classified coronary luminal narrowing into three categories: (a) central, (b) eccentric slit-like, and (c) eccentric polymorphous (Fig. 5).2 The eccentric slit-like lumen, although severly narrowed, has one dimension nearly as wide as the original lumen. The eccentric polymorphous lumen may be circular or angulated. OUT experience suggests that the incidence of the eccentric slit-like lumen is unusually high when there is disagreement between the arteriogram and the pathologic examination. The apparent reason for this is that in certain arteriographic projections, the lumen may appear to be of normal width when it is in fact severely narrowed. Physiologic and angiocarcliographic investigations of left ventricular function should be correlated with pathologic findings. Of
CURRENT TOPICS
Figure 5. Three types of lumens seen in obstructive atherosclerosis. a, Central and circular lumen. (Elastic tissue stain. x 15.) b, Eccentric and polymorphous lumen. (Elastic tissue stain. X 13). c, Eccentric and slitlike lumen. (Elastic tissue stain. x 13.)
7
HUMAN PATHOLOGY-VOLUME 3, NUMBER i
-s
Marct: 1972
Figure 6. Healed subendocardial myocardial infarction in the inferoseptal area of the basal portion of the left ventricle. The adjacent posteromedial papillary muscle is also scarred. The remaining part of the infarct, the medial edge of which is outlined by arrows, is partly overhung by the posterior lea net of the mitral valve and may be overlooked. Hollowing of the left ventricular cavity is suggestive of the presence of such an infarct.
special interest are segments of the left ventricle that either fail to contract or contract asynchronously with the remainder of the wall. Usually such segments are the site of healed infarction, It is important to emphasize that certain healed subendocardial infarcts may escape attention, especially when the heart has been opened in the standard fashion rather
than cut into a series of cross sections. This is particularly true of infarcts at the junction of the ventricular septum and the diaphragmatic aspect of the left ventricle at its base (Fig. 6). This area is overhung by the posterior leaflet of the mitral valve. From the endocardial view the site of the lesion may be marked by a shallow depression with slight endocardial thickening.
Slice I. (apex)
8
Figure 7. Diagram of cross sections of ventricular portion of heart viewed from above. Shaded areas indicate zones that may be sectioned to "spot check" the myocardium in the distribution of each of the three coronary arteries.
CURRENT TOPICS Even on cross sectioning an infarct in this region may be overlooked because of the small amount of scar tissue present. Any questionable gross alteration requires a section for its elucidation. In general, sections of myocardium for histologic studies are taken from areas with obvious gross lesions. However, in all cases of coronary arterial disease, whether or not the patient has had an operation, at least three spot-check sections should be taken, one from the area of distribution of each of the coro-
nary arteries (Fig. 7). This type of examination may disclose early changes of acute myocardial infarction that are invisible on gross inspection. References 1. Vlodaver , 2., and Edwards, J. E.: Pathologic changes in aortic-coronary arrerial saphenous vein grafts. Circulation, 44:719, 1971. 2. Vlodaver, A., and Edwards, J. E.: Pathology of coronary atherosclerosis. I'rog. Carrliov, Dis" /4:256, 1971.
Department of Pat!1ology Charles T. Miller Hospital 125 West College Avenue St. Paul, Minnesota 55 J 02 (Dr. Edwards)
9