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Separation of neointima from Dacron graft causing obstruction
J
THORAC CARDIOVASC SURG
82:268-271, 1981
Separation of neointima from Dacron graft causing obstruction Case following Fontan procedure for tricuspid atresia A nine-year-old patient with tricuspid atresia and normally related great vessels underwent a Fontan procedure, in which a porcine valved Dacron conduit was interposed between the right atrium and pulmonary trunk. After death, 6 months postoperatively, pathological examination revealed a thick layer of neointima (peel) lining the conduit. The peel was thicker in the segment of the conduit proximal to the valve, where it measured up to 4.5 mm in thickness. Proximal to the valve, the peel had separated from the wall of the graft and a hematoma had developed between the separated peel and graft. The result was reduction in the caliber of the conduit to about half the original. The patient's final illness was complicated, being associated with acute pancreatitis. Reduction in the caliber of the graft may have contributed to the death.
Giora Ben-Shachar, M.D., Demetre M. Nicoloff, M.D., and Jesse E. Edwards, M.D., Minneapolis and St. Paul, Minn.
In
certain types of congenital heart disease, conduits of man-made materials have been employed to connect a cardiac chamber to a great artery .1-8 From personal communication with individuals from several centers, * and from our own experience, it is evident that, with time, there is a strong tendency for a thick fibrous lining (peel) to develop within conduits involving the lesser circulation. In valved conduits this material may interfere with the function of the valve and yield obstructive pressure gradients. Also, the new fibrous tissue may separate from the conduit wall and obstruct the channel. The latter phenomenon occurred in the case to be reported.
From the Departments of Pediatrics, Surgery, and Pathology, University of Minnesota, Minneapolis, Minn., and the Departments of Surgery and Pathology, United Hospitals, St. Paul, Minn. Supportedby PublicHealth ServiceResearch Grant 5 R01 HL05694 from the National Heart, Lung and Blood Institute. Received for publication Nov. 25, 1980. Accepted for publication Jan. 20, 1981. Address for reprints: Jesse E. Edwards, M.D., Department of Pathology, United Hospitals, 333 No. Smith Ave., St. Paul, Minn. 55102. *Personalcommunications from D. N. Ross, P. A. Ebert, and D. C. McGoon.
268
Case report Clinical manifestations. While a neonate, a 9'/z-year-old cyanotic boy had been given a diagnosis of tricuspid atresia with pulmonary valvular stenosis and normally related great vessels. A right hemiparesis developed at I year of age. A right Blalock-Taussig shunt, done at 14 months of age, produced improvement in cyanosis and exercise tolerance. A Fontan procedure was carried out at the age of 9 years. This involved insertion of a 22 mm Hancock conduit between the right atrium and the origin of the pulmonary trunk, an end-to-side anastomosis being done at each site. An atrial septal defect was closed with running stitches. Through the pulmonary arteriotomy a search was made for a ventricular septal defect but none was identified. After the operation, the patient was maintained on digoxin and spironolactone-hydrochlorothiazide (Aldactazide). During the first postoperative month there were transient moderate bilateral pleural effusions and ascites. The child gradually increased physical activity and was acyanotic. Six months following the operation, abdominal pain appeared. The patient became lethargic, vomited, and had convulsions. On arrival at the hospital, the patient was unconscious, convulsive, and cyanotic. The blood pressure was unobtainable and the peripheral arterial pulse was thready. A Grade 2/6 ejection systolic murmur was heard along the left sternal border. The abdomen was rigid, and an abdominal paracentesis yielded no fluid. Crystalloids, blood, and blood products were immediately given and caused the cardiac output to improve, with pressures rising to the general level of 110/85 mm Hg. The central venous pressure was maintained at 23 to 30 mm Hg, although decreases to levels slightly below 23
0022-5223/811080268+04$00.40/0 © 1981 The C. V. Mosby Co.
Volume82 Number 2 August, 1981
Separation of neointima from Dacron graft
269
Fig. 1. The proximal segment of the Dacron conduit and its connection with the right atrium (RA). A thick neointima (N), or peel, lines the inside of the conduit and is continuous at its lower end with right atrial endocardium. Separation of neointima from graft in this view is artifact demonstrating the lack of union of neointima with graft. mm Hg did not have a measurable effect on the systemic blood pressure. On this admission, initial laboratory studies showed several abnormalities including signs of severe disseminated coagulopathy, hypoglycemia, high values for both serum and urinary amylase, and low levels for serum insulin. Serum cortisone levels were normal. Surgical exploration of the abdomen revealed acute pancreatitis, and no procedure except biopsy was done. The postoperative course was complicated by development of renal failure, adrenal failure, continuation of disseminated intravascular coagulopathy, and severe neurological deficit with loss of brain-stem function. On the seventh postoperative day, the patient developed cardiac arrest that did not respond to resuscitation. Pathological features. At autopsy, signs of acute pancreatitis and focal renal tubular necrosis were present. The heart showed the anatomic findings of tricuspid atresia with normally related great vessels (type Ib). The right atrium was dilated and had a thickened wall. A Hancock valved conduit extended from the lateral wall of the right atrium and was connected to the origin of the pulmonary artery. The right ventricular infundibulum communicated with the left ventricle through a ventricular septal defect measuring 7 mm in diameter. The infundibulum was free of clots. The conduit was lined throughout its circumference by a gray layer, or peel. This was much thicker proximal to the porcine valve, where it reached a thickness of 4.5 mm (Fig. I), than distal to the valve. At its proximal end, the peel seemed to be continuous with the endocardial tissue of the right atrium. The. neointima was easily separated from the lining of the conduit. The neointima just proximal ~o the porcine valve was found to be separated from the conduit wall
Fig. 2. Conduit proximal to valve (V). In right upper angle there is a wide space between the neointima and the graft containing a hematoma (H). Elsewhere, separation of neointima from graft is as in Fig.!. by a large hematoma (Figs. 2 and 3). The hematoma, together with the separated flap or peel, caused narrowing of the effective luminal diameter to less than half its original caliber (Fig. 3). The porcine valve cusps were pliable and noncalcified. Histologically, the neointima, or peel, was composed of poorly vascularized connective tissue that was highly collagenous (Fig. 4). The luminal surface was smooth, whereas the aspect against the Dacron graft was serrated, the fingerlike prolongations corresponding with the depressio~s !n the .graft material. There was no evidence that the neointimal tissue had penetrated the thickness of the graft, and it did not join the reactive fibrous tissue lying against the outer aspect of the graft.
Comment The growth of the neointima in the present case was most evident in the proximal part of the conduit up to the level of the valve. It was continuous with the endocardiallayer in the right atrium. The outer surface of this tissue closely followed the contours of the Dacron conduit; however, it was not attached to it but simply
The Journal of Thoracic and Cardiovascular Surgery
270 Ben-Shachar, Nicoloff, Edwards
Fig. 3. Diagrammatic portrayal of the states in case described. a, External view of the valved conduit. b, Longitudinal sectionof the valvedconduit. A neointima lies against the lining of the graft. c, The state at autopsy. The neointima is thick. Proximal to the valve the neointima has separated from the graft. The intervening hematoma causes the lumen of the conduit to be reduced to less than half its original caliber.
Fig. 4. Photomicrograph of neointima, or peel. It is composed of dense, poorly vascularized connective tissue. (Hematoxylin and eosin x400.) lay against it. The separation of the neointima and the subjacent hematoma caused significant narrowing of the conduit. Whether it had occurred spontaneously or following the chest trauma of resuscitation at the time of the last hospital admission is unknown. Because of the complexities of this patient's terminal illness, it is unclear whether obstruction of the conduit by the process of separation of the neointima was the immediate cause of the patient's death. However, it had the poten-
tial for such an event. Bisset and associates'' studied children with reconstructed right ventricular outflow tracts by the use of heterograft conduits. Among 19 patients in whom hemodynamic studies were done from I month to 3 years postoperatively, there were seven with gradients of over 40 mm Hg at the conduit level. The nature of the obstruction, however, was not described. Obstruction of conduits by an ingrowth of fibrous tissue measuring about Vs inch in thickness was found in three patients of Ross' series. * A similar tissue growth into artificial conduits has been observed by Ebert* and by Gale and associates." In none of the cases was separation of the neointima a cardinal component. The impression in both series was that the neointima tends to form and be looser in conduits placed in the lesser than greater circulations. Thus it seems that there is a growing experience for the tendency of neofibrous tissue to develop in conduits mainly placed on the right side of the heart. The neointima, of itself, may obstruct the lumen of the conduit or it may separate from the conduit wall, as in our case, and cause obstruction in that way. *Personal communications.
REFERENCES Lillehei CW, Levy MJ, Adams P, Anderson RC: Corrective surgeryfor tetralogyof Fallot. Long-term follow-up by
Volume 82 Number 2
Separation of neointima from Dacron graft
27 1
August. 1981
2
3
4 5
postoperative recatheterization in 69 cases and certain surgical considerations. J THoRAc CARDIOVASC SURG 48: 556-576, 1964 Rastelli GC: A new approach to "anatomic" repair of transposition of the great arteries. Mayo Clin Proc 44: 1-12, 1969 Rastelli GC, Wallace RB, Ongley PA: Complete repair of transposition of the great arteries with pulmonary stenosis. A review and report of a case corrected by using a new surgical technique. Circulation 39:83-95, 1969 Fontan F, Baudet E: Surgical repair of tricuspid atresia. Thorax 26:240-248, 1971 Kouchoukos NT, Barcia A, Bargeron LM, Kirklin JW: Surgical treatment of congenital pulmonary atresia with ventricular septal defect. J THORAC CARDIOVASC SURG 61:70-84, 1971
6 McGoon DC, Wallace RB, Danielson GK: The Rastelli operation. Its indications and results. J THORAC CARDIOVASC SURG 65:65-75, 1973 7 Fontan F, Choussat A, Coqueran J, Baudet E: Repair of tricuspid atresia. Thorax 26:240-248, 1971 8 Gale AW, Danielson GK, McGoon DC, Mair DD: Modified Fontan operation for univentricular heart and complicated congenital lesions. J THORAC CARDIOVASC SURG 78:831-838, 1979 9 Bisset GS Ill, Schwartz DC, Benzing G, Helmsworth J, Kaplan S: Late results of reconstruction of the right ventricular outflow tract with valved external conduits in children (abstr). Am J Cardiol 45:448, 1980
THORAC CARDIOVASC SURG
82:268-271, 1981
Separation of neointima from Dacron graft causing obstruction Case following Fontan procedure for tricuspid atresia A nine-year-old patient with tricuspid atresia and normally related great vessels underwent a Fontan procedure, in which a porcine valved Dacron conduit was interposed between the right atrium and pulmonary trunk. After death, 6 months postoperatively, pathological examination revealed a thick layer of neointima (peel) lining the conduit. The peel was thicker in the segment of the conduit proximal to the valve, where it measured up to 4.5 mm in thickness. Proximal to the valve, the peel had separated from the wall of the graft and a hematoma had developed between the separated peel and graft. The result was reduction in the caliber of the conduit to about half the original. The patient's final illness was complicated, being associated with acute pancreatitis. Reduction in the caliber of the graft may have contributed to the death.
Giora Ben-Shachar, M.D., Demetre M. Nicoloff, M.D., and Jesse E. Edwards, M.D., Minneapolis and St. Paul, Minn.
In
certain types of congenital heart disease, conduits of man-made materials have been employed to connect a cardiac chamber to a great artery .1-8 From personal communication with individuals from several centers, * and from our own experience, it is evident that, with time, there is a strong tendency for a thick fibrous lining (peel) to develop within conduits involving the lesser circulation. In valved conduits this material may interfere with the function of the valve and yield obstructive pressure gradients. Also, the new fibrous tissue may separate from the conduit wall and obstruct the channel. The latter phenomenon occurred in the case to be reported.
From the Departments of Pediatrics, Surgery, and Pathology, University of Minnesota, Minneapolis, Minn., and the Departments of Surgery and Pathology, United Hospitals, St. Paul, Minn. Supportedby PublicHealth ServiceResearch Grant 5 R01 HL05694 from the National Heart, Lung and Blood Institute. Received for publication Nov. 25, 1980. Accepted for publication Jan. 20, 1981. Address for reprints: Jesse E. Edwards, M.D., Department of Pathology, United Hospitals, 333 No. Smith Ave., St. Paul, Minn. 55102. *Personalcommunications from D. N. Ross, P. A. Ebert, and D. C. McGoon.
268
Case report Clinical manifestations. While a neonate, a 9'/z-year-old cyanotic boy had been given a diagnosis of tricuspid atresia with pulmonary valvular stenosis and normally related great vessels. A right hemiparesis developed at I year of age. A right Blalock-Taussig shunt, done at 14 months of age, produced improvement in cyanosis and exercise tolerance. A Fontan procedure was carried out at the age of 9 years. This involved insertion of a 22 mm Hancock conduit between the right atrium and the origin of the pulmonary trunk, an end-to-side anastomosis being done at each site. An atrial septal defect was closed with running stitches. Through the pulmonary arteriotomy a search was made for a ventricular septal defect but none was identified. After the operation, the patient was maintained on digoxin and spironolactone-hydrochlorothiazide (Aldactazide). During the first postoperative month there were transient moderate bilateral pleural effusions and ascites. The child gradually increased physical activity and was acyanotic. Six months following the operation, abdominal pain appeared. The patient became lethargic, vomited, and had convulsions. On arrival at the hospital, the patient was unconscious, convulsive, and cyanotic. The blood pressure was unobtainable and the peripheral arterial pulse was thready. A Grade 2/6 ejection systolic murmur was heard along the left sternal border. The abdomen was rigid, and an abdominal paracentesis yielded no fluid. Crystalloids, blood, and blood products were immediately given and caused the cardiac output to improve, with pressures rising to the general level of 110/85 mm Hg. The central venous pressure was maintained at 23 to 30 mm Hg, although decreases to levels slightly below 23
0022-5223/811080268+04$00.40/0 © 1981 The C. V. Mosby Co.
Volume82 Number 2 August, 1981
Separation of neointima from Dacron graft
269
Fig. 1. The proximal segment of the Dacron conduit and its connection with the right atrium (RA). A thick neointima (N), or peel, lines the inside of the conduit and is continuous at its lower end with right atrial endocardium. Separation of neointima from graft in this view is artifact demonstrating the lack of union of neointima with graft. mm Hg did not have a measurable effect on the systemic blood pressure. On this admission, initial laboratory studies showed several abnormalities including signs of severe disseminated coagulopathy, hypoglycemia, high values for both serum and urinary amylase, and low levels for serum insulin. Serum cortisone levels were normal. Surgical exploration of the abdomen revealed acute pancreatitis, and no procedure except biopsy was done. The postoperative course was complicated by development of renal failure, adrenal failure, continuation of disseminated intravascular coagulopathy, and severe neurological deficit with loss of brain-stem function. On the seventh postoperative day, the patient developed cardiac arrest that did not respond to resuscitation. Pathological features. At autopsy, signs of acute pancreatitis and focal renal tubular necrosis were present. The heart showed the anatomic findings of tricuspid atresia with normally related great vessels (type Ib). The right atrium was dilated and had a thickened wall. A Hancock valved conduit extended from the lateral wall of the right atrium and was connected to the origin of the pulmonary artery. The right ventricular infundibulum communicated with the left ventricle through a ventricular septal defect measuring 7 mm in diameter. The infundibulum was free of clots. The conduit was lined throughout its circumference by a gray layer, or peel. This was much thicker proximal to the porcine valve, where it reached a thickness of 4.5 mm (Fig. I), than distal to the valve. At its proximal end, the peel seemed to be continuous with the endocardial tissue of the right atrium. The. neointima was easily separated from the lining of the conduit. The neointima just proximal ~o the porcine valve was found to be separated from the conduit wall
Fig. 2. Conduit proximal to valve (V). In right upper angle there is a wide space between the neointima and the graft containing a hematoma (H). Elsewhere, separation of neointima from graft is as in Fig.!. by a large hematoma (Figs. 2 and 3). The hematoma, together with the separated flap or peel, caused narrowing of the effective luminal diameter to less than half its original caliber (Fig. 3). The porcine valve cusps were pliable and noncalcified. Histologically, the neointima, or peel, was composed of poorly vascularized connective tissue that was highly collagenous (Fig. 4). The luminal surface was smooth, whereas the aspect against the Dacron graft was serrated, the fingerlike prolongations corresponding with the depressio~s !n the .graft material. There was no evidence that the neointimal tissue had penetrated the thickness of the graft, and it did not join the reactive fibrous tissue lying against the outer aspect of the graft.
Comment The growth of the neointima in the present case was most evident in the proximal part of the conduit up to the level of the valve. It was continuous with the endocardiallayer in the right atrium. The outer surface of this tissue closely followed the contours of the Dacron conduit; however, it was not attached to it but simply
The Journal of Thoracic and Cardiovascular Surgery
270 Ben-Shachar, Nicoloff, Edwards
Fig. 3. Diagrammatic portrayal of the states in case described. a, External view of the valved conduit. b, Longitudinal sectionof the valvedconduit. A neointima lies against the lining of the graft. c, The state at autopsy. The neointima is thick. Proximal to the valve the neointima has separated from the graft. The intervening hematoma causes the lumen of the conduit to be reduced to less than half its original caliber.
Fig. 4. Photomicrograph of neointima, or peel. It is composed of dense, poorly vascularized connective tissue. (Hematoxylin and eosin x400.) lay against it. The separation of the neointima and the subjacent hematoma caused significant narrowing of the conduit. Whether it had occurred spontaneously or following the chest trauma of resuscitation at the time of the last hospital admission is unknown. Because of the complexities of this patient's terminal illness, it is unclear whether obstruction of the conduit by the process of separation of the neointima was the immediate cause of the patient's death. However, it had the poten-
tial for such an event. Bisset and associates'' studied children with reconstructed right ventricular outflow tracts by the use of heterograft conduits. Among 19 patients in whom hemodynamic studies were done from I month to 3 years postoperatively, there were seven with gradients of over 40 mm Hg at the conduit level. The nature of the obstruction, however, was not described. Obstruction of conduits by an ingrowth of fibrous tissue measuring about Vs inch in thickness was found in three patients of Ross' series. * A similar tissue growth into artificial conduits has been observed by Ebert* and by Gale and associates." In none of the cases was separation of the neointima a cardinal component. The impression in both series was that the neointima tends to form and be looser in conduits placed in the lesser than greater circulations. Thus it seems that there is a growing experience for the tendency of neofibrous tissue to develop in conduits mainly placed on the right side of the heart. The neointima, of itself, may obstruct the lumen of the conduit or it may separate from the conduit wall, as in our case, and cause obstruction in that way. *Personal communications.
REFERENCES Lillehei CW, Levy MJ, Adams P, Anderson RC: Corrective surgeryfor tetralogyof Fallot. Long-term follow-up by
Volume 82 Number 2
Separation of neointima from Dacron graft
27 1
August. 1981
2
3
4 5
postoperative recatheterization in 69 cases and certain surgical considerations. J THoRAc CARDIOVASC SURG 48: 556-576, 1964 Rastelli GC: A new approach to "anatomic" repair of transposition of the great arteries. Mayo Clin Proc 44: 1-12, 1969 Rastelli GC, Wallace RB, Ongley PA: Complete repair of transposition of the great arteries with pulmonary stenosis. A review and report of a case corrected by using a new surgical technique. Circulation 39:83-95, 1969 Fontan F, Baudet E: Surgical repair of tricuspid atresia. Thorax 26:240-248, 1971 Kouchoukos NT, Barcia A, Bargeron LM, Kirklin JW: Surgical treatment of congenital pulmonary atresia with ventricular septal defect. J THORAC CARDIOVASC SURG 61:70-84, 1971
6 McGoon DC, Wallace RB, Danielson GK: The Rastelli operation. Its indications and results. J THORAC CARDIOVASC SURG 65:65-75, 1973 7 Fontan F, Choussat A, Coqueran J, Baudet E: Repair of tricuspid atresia. Thorax 26:240-248, 1971 8 Gale AW, Danielson GK, McGoon DC, Mair DD: Modified Fontan operation for univentricular heart and complicated congenital lesions. J THORAC CARDIOVASC SURG 78:831-838, 1979 9 Bisset GS Ill, Schwartz DC, Benzing G, Helmsworth J, Kaplan S: Late results of reconstruction of the right ventricular outflow tract with valved external conduits in children (abstr). Am J Cardiol 45:448, 1980