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Aortic valve replacement with fascia lata
Aortic valve replacement with fascia lata An encouraging late study /n /969, surgeons at the Toronto General Hospital began using frame-mounted autologous fascia lata for valve replacement. This technique was discontinued midway through 1970 when a prosthesis failed in the tricuspid valve area. During this time 36 patients had undergone isolated aortic valve replacement, and all survivors have now been followed for 3 112 years. Thirty-one are still alive and well. None has received anticoagulants and none has suffered from thromboembolism or hemolysis. Three patients have died from causes unrelated to the valve. Complete hemodynamic studies were obtained in 26 of the 31 survivors 3th years after valve replacement. These data compare favorably to information obtained in 18 of the patients who were catheterized both 6 months and 3th years after operation. We now believe that the fascia lata eventually dies, acting merely as a scaffold for a pseudointimal covering. This ingrowth is self-limiting and does not impair valve function for at least 3th years. Although autologous fascia lata may ultimately prove to have a limited functional life, its period of usefulness can now be gauged in years. The excellent clinical and hemodynamic results in this group of patients have been exceptionally gratifying. These results have stimulated us to return to this technique for aortic valve replacement.
Alan S. Trimble, M.D., B.Sc.(Med.), F.R.C.S.(C.), F.A.C.S., John Gunstensen, M.B., Ch.B., F.R.C.S.(Edin.), Malcolm D. Silver, M.D., Ph.D., Harold E. Aldridge, M.B.B.S., F.R.C.P.(c.), Leonard Schwartz, M.D., F.R.C.P.(C.), and John E. Morch, M.D., C.M., F.R.c.p.(e.) , Toronto, Ontario, Canada
Senning' pioneered the use of autologous fascia lata as a free graft in the management of aortic valvular heart disease. Ionescu subsequently devised a technique for molding the fascia onto a frame to create a trileaflet valve for use in any cardiac position and with ROSS2 reported the first comprehensive clinical series in 1969. From the Divisions of Cardiovascular Surgery, Pathology, and Cardiology, Toronto General Hospital and University of Toronto, Toronto, Ontario, Canada. Supported by the Medical Research Council and the Ontario Heart Foundation. Received for publication March 18, 1974. Address for reprints: Alan S. Trimble, M.D., Cardiovascular Unit, Toronto General Hospital, 101 College Street, Toronto, Ontario M5G lL7, Canada.
Beginning in November, 1969, their method was used in a consecutive and unselected group of patients who underwent single or multiple valve replacements at the Toronto General Hospital. 3 The series was discontinued in July, 1970, when the failure of a prosthesis in the tricuspid valve area became evident. During this period 36 patients were subjected to isolated aortic valve replacement. As part of their follow-up, 18 were reassessed hemodynamically after 6 months. It was decided that a full 5 years would be allowed to elapse before they were studied again. However, the clinical well-being of all of the patients has proved so gratifying 219
The Journal 01
220
Trimble et al.
Thoracic and Cardiovascular Surgery
Table I. Preoperative catheterization data of 36 patients undergoing aortic valve replacement with fascia lata No. of patients
Cardiac index* (L./min./sq. M.)
Peak systolic gradient" (mm. Hg)
Stenosis
11
3.20 (2.16-4.68 )
105 (76-150)
None to mild
Incompetence
II
3.02 (1.6 -5.37)
7 ( 0- 25)
Severe
Mixed
14
Dominant lesion
3.22 (2.30-4.47)
75 (25-110)
A ngiographic insufficiency
Moderate to severe
LVEDP* (mm, Hg)
19 ( 9-30) 24 (15-45) 25 (12-42 )
Legend: LVEDP, Left ventricular end-diastolic pressure . • Average (range).
that it was thought worthwhile to document this impression by cardiac catheterization. As a result they were restudied 3~ years after valve replacement. The clinical, hemodynamic, and pathological material from this series of isolated aortic valve replacements forms the basis of this presentation. Clinical material The 36 patients ranged in age from 19 to 70 years; 29 were men and 7 were women. No patient was denied operation because of the end-stage nature of his disease. Two had undergone previous valve replacement operations and 2 others had additional lesions-a chronic dissection of the ascending aorta and a ventricular septal defect. The preoperative cardiac catheterization data are summarized in Table I. Eleven patients had dominant aortic stenosis, 11 had incompetence, and 14 had a mixed lesion. Operative technique The technique of valve preparation has been described previously." The fascia was removed from the thigh after meticulous skin preparation. After hemostasis the wound was immediately closed with suction drainage. Tensor bandages were run from the toes to the thigh for 48 hours. Prosthetic valve size was calculated from an evaluation of the preoperative aortic root angiogram. This method proved reliable, and it was never necessary to gusset
the aortic root in order to accommodate a prosthesis that was too large. We commonly used the 20 and 22 mm. diameter stents. Thin fascia from the middle or anterior part of the thigh was used, with care taken to avoid the natural perforations that are always present. The smooth, deep aspect of the fascia was always placed on the concave or sinus side of the aortic cusp. During valve molding, the tissue was soaked in an antibiotic solution. The commissural areas were buttressed with Teflon velour pledgets, and care was taken to remove fascia from the base of the cusp, freeing the sewing skirt. Assessment of valve competence was purely visual without additional testing methods. All operations were undertaken with normothermic cardiopulmonary bypass. Attempts were made to remove all calcium from the aortic root. The valves were inserted with an interrupted figure-of-eight suture technique. Particular care was taken to avoid picking up the fascia at the base of the cusp to prevent distortion with the tying of the sutures. Postoperatively, antibiotics were given for 5 days. Results Operative deaths. There were two operative deaths (6 per cent). In I patient the prosthesis occluded a low-lying left coronary ostium in a heavily calcified aortic root, and remedial measures resulted in aortic laceration and uncontrollable hemor-
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rhage. In the other patient the operation had proceeded routinely until ventricular fibrillation occurred during chest closure. No specific cause was found at autopsy. Late deaths. Three other patients have died: The first died 5 weeks postoperatively from a gram-negative septicemia secondary to a chronic genitourinary tract infection. Another had been clinically well for 5 months but presented with a febrile illness and recurrent systemic emboli that grew Aspergillus. At his death 6 months postoperatively, an extensive mediastinitis and aortitis was present originating at the aortotomy site. Contrary to expectations, the aortic fascial valve was not involved by the disease process. The third patient, who was exceedingly well, was killed in an automobile accident 2 years after valve insertion. She had been catheterized 6 months after the operation, and the valve was found to be functioning perfectly. At autopsy the prosthesis was grossly normal. Clinical follow-up Thirty-one patients are alive 3 ~ years after operation. Twenty-eight are symptom free and taking no cardiac medications . Three others have recently developed minimal cardiac symptoms. Anticoagulation has not been used, and there have been no instances of thromboembolism. Three patients had febrile illness during the follow-up period, and in I a bacteremia was confirmed. All were treated with antibiotics for 6 weeks, none has late evidence of valve dysfunction, and indeed it is questionable whether any form of endocarditis was ever present. On discharge from the hospital, most patients had a Grade 1/6 to 2/6 ejection systolic murmur localized to the left sternal border. Often this was accompanied by a systolic click, and both sounds have been recorded at phonocardiography (Fig. I). They appear to be characteristic of flow across the fascia lata aortic prosthesis. These murmurs have not changed in any patient over the 3 Yz year follow-up. Eighteen patients have no early diastolic
SC ~
• :
...... :
.t .
I . ...r.... ~
,·~
SM
Fig. 1. Aortic and left ventricular pressures and phonocardiography 6 months after insertion of fascia lata aortic valve. The typical systolic murmur (SM) and systol ic ejection click (SC) are shown.
murmur of prosthetic valvular insufficiency. Seven have a localized murmur of Grade 1/6 intensity and 6 have a murmur of Grade 2/6 intensity. In 7 of these 13 patients the murmur was present at 6 months and has not changed over the period of follow-up. In 3 it has definitely increased over this period. The other 3 patients were not seen at 6 months; therefore, information is lacking as to any changes. None of the patients has peripheral signs of aortic incompetence. There has been no hemolysis as estimated by blood hemoglobin levels and reticulocyte counts. Hemodynamic studies Six months after operation. Complete cardiac catheterization including aortic root angiography was performed in 18 patients 6 months after operation. The details are listed in Table II. The cardiac index
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Thoracic and Ccrdievescurer Surgery
200-
A
B
Fig. 2. Aortic and left ventricular pressures 6 months after insertion of fascia lata aortic valve . There is a minimal gradient at rest (A) which is unchanged during exercise (B) .
Table II. Postoperative catheterization data in 18 patients 6 months after insertion of fascia lata aortic valve Valve size (mm.)
No. of patients
Cardiac index* (L./min./sq . M.)
Peak systolic gradient" (mm. Hg)
20
6
3.03 (1.91-4.14 ) 3.52 ( 1.29-5.2) 2.25
(0-23 ) 10 (0·25 ) 0
22 24
II
11
LVEDP* (mm. Hg) 14 (9-21 ) 14 (6-20 ) 6
Legend: LVEDP. Left ventricular end-diastolic pressure. ·Average (range).
averaged 2.93 L. per minute per square meter (range 1.29 to 5.2) and the left ventricular end-diastolic pressure averaged 7 mm. Hg (range 6 to 21 mm. Hg). Peak systolic gradients across the fascia prosthesis varied from zero to 25 mm. Hg with an average of 7 mm. Hg. Mean integrated gradients varied between zero and 40 mm. Hg. They did not change with exercise (Fig. 2) and were thought to be due to delayed opening of the fascia lata valve which, in addition to producing the gradients, created a systolic click. Aortic insufficiency was either absent or trivial in 9 patients and was mild in the remaining 9.
Three and one-half years after operation. Twenty-six patients consented to full hemodynamic studies 3lh years postoperatively (Table III). In summary, the cardiac index averaged 3.15 L. per minute per square meter and the left ventricular end-diastolic pressure ranged from 2 to 28 mm. Hg (average 13 mm. Hg). Peak systolic gradients, demonstrated in nearly 80 per cent of the patients, ranged from 0 to 35 mm. Hg with an average of 13 mm. Hg. Their frequency and magnitude were related to the size of the fascia prosthesis . Exercise produced no demonstrable increase in the gradient. There has been no progression of this systolic gradi-
Volume 68
223
Aortic valve replacement with fascia lata
Number 2 August, 1974
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Fig. 3. Aortic and left ventricular pressures 6 months and 31;2 years after insertion of fascia lata aortic valve. No gradient is present at 6 months (A ), at 31;2 years (B ), or on exercise (C).
Table III. Postoperative catheterization data in 25 patients 3lh years after aortic valve replacement with fascia lata Valve size (mm .)
No. of patients
18
2
20
10
22
13
24
Cardiac index* (L .!min.!sq. M .)
Peak systolic gradient" (m m, Hg)
LVEDP* (mm . Hg )
2.81 (2.45-3.18 ) 3.36 (2.40-5.8 ) 3.25 (2.03-4.60 ) 3.18
19 (13-25 ) 19 ( 0-35) 12 ( 0-30) 0
9 (7-11) 12 (2-22 ) 14 (7-28) 16
Legend: LVEDP. Left ventricular end-diastolic pressure . • Average (ra nge) .
ent in the 15 patients who were studied after both 6 months and 3 ~ years (Fig. 3). Aortic root angiography was performed on all 26 patients, 14 of whom had no or trivial insufficiency. In 7 the insufficiency was graded mild and in 5 it was considered moderate (Table IV). Comparing the degree of insufficiency seen after 6 months to that noted after 3 ~ years suggests that insufficiency has progressed in only 3 patients. None was clinically disabled as a result of the insufficiency. The lack of correlation between the clinical and angio-
graphic assessments of insufficiency supports the contention that catheter documentation of valve function is always necessary in any follow-up study. Pathology
Autopsy has been performed on all 5 patients who died. No gross or microscopic abnormalities were seen in the valves acquired from the 2 patients who died in the operating room. The valve examined 5 weeks after insertion (the patient died of septicemia) was macroscopically normal. A minimal thick-
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Trimble et al.
Thoracic and Card iovascular Surgery
Fig. 4. Photomicrographs of the cusps of fascia lata aortic prostheses. Separate bundles of collagen fibers in the fascia are still obvious 5 weeks after insertion (A). Note fibrin material deposited on surface (arrow). Bundles of collagen fibers are no longer readily recognizable after the prosthesis has been in place 6 and 23 months (B and C) . Also, the original fascia has lost most of its cellularity. Its surfaces have been covered by an organized fibrin deposit that forms a pseudointima (P). The latter matures and tends to become more compact the longer the valve remains in the aortic area. In all instances, the segment of cusp nearest its free margin is uppermost. (Combined Masson trichrome-Verhoeff elastic stain; original mag- . nification x20. )
Table IV. Angiographic incompetence in 26 patients 3 ~ years after aortic valve replacement with fascia lata Grade
No. of patients
Trivial (0) Mild Moderate
14
7
5
ening, produced by a fine covering of translucent tissue, caused rounding of the free margins of the cusps and was more pronounced in their concavity. Microscopically, this covering was composed of a thin layer of organized fibrin (pseudointima) (Fig. 4, A). The underlying collagen bundles of the original fascia lata were totally acellular. The valve seen 6 months after implantation had been removed from the patient with a complicating Aspergillus infection involving the ascending aorta. The valve had not been invaded although a granulating mass of infected tissue lay within 1
em. of it. Its cusps were slightly thickened but nevertheless pliable, and the valve was totally competent. The pseudointimal covering had matured in comparison with the earlier valve and was thickest at the base of the cusps. The original fascia lata was relatively acellular, but the linear arrangement of the collagen bundles was still present (Fig. 4, B). The thickness of the cusps at 23 months was notably greatter than that seen at 5 weeks. The cusps were still pliable and the valve was totally competent. Microscopically, the changes were very similar to those noted at () months (Fig. 4, C). Discussion
The early failure of a frame-mounted fascia lata valve in the tricuspid position led to the prompt cessation of its use at this hospital. The fascia was found to be grossly thickened and distorted, changes which produced both stenosis and incompetence of the prosthesis.
Volume 68 Number 2 Augu,t. 1974
Aortic valve replacement with fascia lata
Although the alterations took longer to develop, mitral prostheses then showed similar changes, and we feared that a similar fate would overtake valves in the aortic position. However, progressive thickening does not appear to be a significant problem, and our late hemodynamic studies indicate that there is a fundamental difference between the behavior of fascia lata prostheses in the atrioventricular ring and that in the aortic ring. The pathological material available to us is limited, but our studies of it do suggest that the fascia itself is not viable and probably acts as a temporary support for the development of a pseudointimal covering. This covering extends over the whole fascial cusp, in contrast to the limited growth that has been described in homografts.' Perhaps it may offer longer support to the underlying collagen and prevent its ultimate breakdown. If this is so, the advantages of the fascial prosthesis may outweigh any disadvantages. Of particular concern was the late development of incompetence in 3 patients. In 2, the operative note specifically mentioned that one cusp was shorter than the others; it seems likely that the cause of valve dysfunction could be related to imperfections in the valve manufacture. On comparing the incidence of incompetence (whether mild or moderate) of valves inserted in the first 4 months with that of valves inserted in the second 4 months, we were surprised to find 10 out of 13 valves incompetent in the first period compared with 2 out of 13 in the second. This probably reflects our increasing familiarity with the manufacture of the valves and emphasizes the importance of perfection in their molding. The task was not relegated to a technical assistant, and the time added to the operative procedure by the necessity of the surgeon himself or a highly experienced assistant making the valve was not prohibitive. Although others" have suggested that the fascial valve is particularly prone to infection, our experience has not shown this. On the contrary, autopsy showed that the
225
valve was not involved in 2 patients who died from infection. Hemodynamically, the fascial valve possesses the advantage of central-flow prosthetic valves. In particular, it performs very well in response to an increased cardiac output associated with exercise. Hemolysis was not seen in this series. Perhaps the greatest benefit, however, has been the total absence of thromboembolic episodes in spite of withholding anticoagulants. This has allowed patients to become entirely independent. In our opinion, they have made a better readjustment to life than the average patient with a prosthetic valve. Some of our patients had not seen a doctor after operation until they were recalled for review. The removal of a portion of fascia lata has not caused any problems with the patients apart from some minor discomfort on driving an automobile when the fascia was removed from the right thigh. For this reason we would suggest that the left thigh be used in order to leave the right leg completely normal for controlling the foot pedals of a car. In conclusion, our late experience with fascia lata for aortic valve replacement has proved most gratifying, both clinically and hemodynamically.
REFERENCES
2 3
4
5 6
Senning, A.: Fascia Lata Replacement of Aortic Valves, J. THoRAC. CARDIOVASC. SURG. 54: 465, 1967. Ionescu, M. I., and Ross, D. N.: Heart Valve Replacement With Autologous Fascia Lata, Lancet 2: 335, 1969. Ionescu, M. I., Ross, D. N., Wooler, G. H., Deac, R., and Ray, R.: Replacement of Heart Valves With Autologous Fascia Lata: Surgical Technique, Br. J. Surg. 57: 437, 1970. Trimble, A. S., and Metni, F. N.: Heart Valve Replacement With Autologous Fascia Lata Using the Ionescu Technique, 1. THORAe. CARDIOVASC. SURG. 61: 385, 1971. Smith, J. c.: The Pathology of Human Aortic Valve Homografts, Thorax 22: 114, 1967. Dubiel, W. T., Johansson, L., and Willen, R.: Postoperative Changes in Autologous Fascia Lata Heart Valve Grafts: A Pathological Study, Ann. Thorac. Surg. 15: 140, 1973.
Alan S. Trimble, M.D., B.Sc.(Med.), F.R.C.S.(C.), F.A.C.S., John Gunstensen, M.B., Ch.B., F.R.C.S.(Edin.), Malcolm D. Silver, M.D., Ph.D., Harold E. Aldridge, M.B.B.S., F.R.C.P.(c.), Leonard Schwartz, M.D., F.R.C.P.(C.), and John E. Morch, M.D., C.M., F.R.c.p.(e.) , Toronto, Ontario, Canada
Senning' pioneered the use of autologous fascia lata as a free graft in the management of aortic valvular heart disease. Ionescu subsequently devised a technique for molding the fascia onto a frame to create a trileaflet valve for use in any cardiac position and with ROSS2 reported the first comprehensive clinical series in 1969. From the Divisions of Cardiovascular Surgery, Pathology, and Cardiology, Toronto General Hospital and University of Toronto, Toronto, Ontario, Canada. Supported by the Medical Research Council and the Ontario Heart Foundation. Received for publication March 18, 1974. Address for reprints: Alan S. Trimble, M.D., Cardiovascular Unit, Toronto General Hospital, 101 College Street, Toronto, Ontario M5G lL7, Canada.
Beginning in November, 1969, their method was used in a consecutive and unselected group of patients who underwent single or multiple valve replacements at the Toronto General Hospital. 3 The series was discontinued in July, 1970, when the failure of a prosthesis in the tricuspid valve area became evident. During this period 36 patients were subjected to isolated aortic valve replacement. As part of their follow-up, 18 were reassessed hemodynamically after 6 months. It was decided that a full 5 years would be allowed to elapse before they were studied again. However, the clinical well-being of all of the patients has proved so gratifying 219
The Journal 01
220
Trimble et al.
Thoracic and Cardiovascular Surgery
Table I. Preoperative catheterization data of 36 patients undergoing aortic valve replacement with fascia lata No. of patients
Cardiac index* (L./min./sq. M.)
Peak systolic gradient" (mm. Hg)
Stenosis
11
3.20 (2.16-4.68 )
105 (76-150)
None to mild
Incompetence
II
3.02 (1.6 -5.37)
7 ( 0- 25)
Severe
Mixed
14
Dominant lesion
3.22 (2.30-4.47)
75 (25-110)
A ngiographic insufficiency
Moderate to severe
LVEDP* (mm, Hg)
19 ( 9-30) 24 (15-45) 25 (12-42 )
Legend: LVEDP, Left ventricular end-diastolic pressure . • Average (range).
that it was thought worthwhile to document this impression by cardiac catheterization. As a result they were restudied 3~ years after valve replacement. The clinical, hemodynamic, and pathological material from this series of isolated aortic valve replacements forms the basis of this presentation. Clinical material The 36 patients ranged in age from 19 to 70 years; 29 were men and 7 were women. No patient was denied operation because of the end-stage nature of his disease. Two had undergone previous valve replacement operations and 2 others had additional lesions-a chronic dissection of the ascending aorta and a ventricular septal defect. The preoperative cardiac catheterization data are summarized in Table I. Eleven patients had dominant aortic stenosis, 11 had incompetence, and 14 had a mixed lesion. Operative technique The technique of valve preparation has been described previously." The fascia was removed from the thigh after meticulous skin preparation. After hemostasis the wound was immediately closed with suction drainage. Tensor bandages were run from the toes to the thigh for 48 hours. Prosthetic valve size was calculated from an evaluation of the preoperative aortic root angiogram. This method proved reliable, and it was never necessary to gusset
the aortic root in order to accommodate a prosthesis that was too large. We commonly used the 20 and 22 mm. diameter stents. Thin fascia from the middle or anterior part of the thigh was used, with care taken to avoid the natural perforations that are always present. The smooth, deep aspect of the fascia was always placed on the concave or sinus side of the aortic cusp. During valve molding, the tissue was soaked in an antibiotic solution. The commissural areas were buttressed with Teflon velour pledgets, and care was taken to remove fascia from the base of the cusp, freeing the sewing skirt. Assessment of valve competence was purely visual without additional testing methods. All operations were undertaken with normothermic cardiopulmonary bypass. Attempts were made to remove all calcium from the aortic root. The valves were inserted with an interrupted figure-of-eight suture technique. Particular care was taken to avoid picking up the fascia at the base of the cusp to prevent distortion with the tying of the sutures. Postoperatively, antibiotics were given for 5 days. Results Operative deaths. There were two operative deaths (6 per cent). In I patient the prosthesis occluded a low-lying left coronary ostium in a heavily calcified aortic root, and remedial measures resulted in aortic laceration and uncontrollable hemor-
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Aortic valve replacement with fascia lata
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Augu sl. 1974
rhage. In the other patient the operation had proceeded routinely until ventricular fibrillation occurred during chest closure. No specific cause was found at autopsy. Late deaths. Three other patients have died: The first died 5 weeks postoperatively from a gram-negative septicemia secondary to a chronic genitourinary tract infection. Another had been clinically well for 5 months but presented with a febrile illness and recurrent systemic emboli that grew Aspergillus. At his death 6 months postoperatively, an extensive mediastinitis and aortitis was present originating at the aortotomy site. Contrary to expectations, the aortic fascial valve was not involved by the disease process. The third patient, who was exceedingly well, was killed in an automobile accident 2 years after valve insertion. She had been catheterized 6 months after the operation, and the valve was found to be functioning perfectly. At autopsy the prosthesis was grossly normal. Clinical follow-up Thirty-one patients are alive 3 ~ years after operation. Twenty-eight are symptom free and taking no cardiac medications . Three others have recently developed minimal cardiac symptoms. Anticoagulation has not been used, and there have been no instances of thromboembolism. Three patients had febrile illness during the follow-up period, and in I a bacteremia was confirmed. All were treated with antibiotics for 6 weeks, none has late evidence of valve dysfunction, and indeed it is questionable whether any form of endocarditis was ever present. On discharge from the hospital, most patients had a Grade 1/6 to 2/6 ejection systolic murmur localized to the left sternal border. Often this was accompanied by a systolic click, and both sounds have been recorded at phonocardiography (Fig. I). They appear to be characteristic of flow across the fascia lata aortic prosthesis. These murmurs have not changed in any patient over the 3 Yz year follow-up. Eighteen patients have no early diastolic
SC ~
• :
...... :
.t .
I . ...r.... ~
,·~
SM
Fig. 1. Aortic and left ventricular pressures and phonocardiography 6 months after insertion of fascia lata aortic valve. The typical systolic murmur (SM) and systol ic ejection click (SC) are shown.
murmur of prosthetic valvular insufficiency. Seven have a localized murmur of Grade 1/6 intensity and 6 have a murmur of Grade 2/6 intensity. In 7 of these 13 patients the murmur was present at 6 months and has not changed over the period of follow-up. In 3 it has definitely increased over this period. The other 3 patients were not seen at 6 months; therefore, information is lacking as to any changes. None of the patients has peripheral signs of aortic incompetence. There has been no hemolysis as estimated by blood hemoglobin levels and reticulocyte counts. Hemodynamic studies Six months after operation. Complete cardiac catheterization including aortic root angiography was performed in 18 patients 6 months after operation. The details are listed in Table II. The cardiac index
The Journol of
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200-
A
B
Fig. 2. Aortic and left ventricular pressures 6 months after insertion of fascia lata aortic valve . There is a minimal gradient at rest (A) which is unchanged during exercise (B) .
Table II. Postoperative catheterization data in 18 patients 6 months after insertion of fascia lata aortic valve Valve size (mm.)
No. of patients
Cardiac index* (L./min./sq . M.)
Peak systolic gradient" (mm. Hg)
20
6
3.03 (1.91-4.14 ) 3.52 ( 1.29-5.2) 2.25
(0-23 ) 10 (0·25 ) 0
22 24
II
11
LVEDP* (mm. Hg) 14 (9-21 ) 14 (6-20 ) 6
Legend: LVEDP. Left ventricular end-diastolic pressure. ·Average (range).
averaged 2.93 L. per minute per square meter (range 1.29 to 5.2) and the left ventricular end-diastolic pressure averaged 7 mm. Hg (range 6 to 21 mm. Hg). Peak systolic gradients across the fascia prosthesis varied from zero to 25 mm. Hg with an average of 7 mm. Hg. Mean integrated gradients varied between zero and 40 mm. Hg. They did not change with exercise (Fig. 2) and were thought to be due to delayed opening of the fascia lata valve which, in addition to producing the gradients, created a systolic click. Aortic insufficiency was either absent or trivial in 9 patients and was mild in the remaining 9.
Three and one-half years after operation. Twenty-six patients consented to full hemodynamic studies 3lh years postoperatively (Table III). In summary, the cardiac index averaged 3.15 L. per minute per square meter and the left ventricular end-diastolic pressure ranged from 2 to 28 mm. Hg (average 13 mm. Hg). Peak systolic gradients, demonstrated in nearly 80 per cent of the patients, ranged from 0 to 35 mm. Hg with an average of 13 mm. Hg. Their frequency and magnitude were related to the size of the fascia prosthesis . Exercise produced no demonstrable increase in the gradient. There has been no progression of this systolic gradi-
Volume 68
223
Aortic valve replacement with fascia lata
Number 2 August, 1974
I 180
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Fig. 3. Aortic and left ventricular pressures 6 months and 31;2 years after insertion of fascia lata aortic valve. No gradient is present at 6 months (A ), at 31;2 years (B ), or on exercise (C).
Table III. Postoperative catheterization data in 25 patients 3lh years after aortic valve replacement with fascia lata Valve size (mm .)
No. of patients
18
2
20
10
22
13
24
Cardiac index* (L .!min.!sq. M .)
Peak systolic gradient" (m m, Hg)
LVEDP* (mm . Hg )
2.81 (2.45-3.18 ) 3.36 (2.40-5.8 ) 3.25 (2.03-4.60 ) 3.18
19 (13-25 ) 19 ( 0-35) 12 ( 0-30) 0
9 (7-11) 12 (2-22 ) 14 (7-28) 16
Legend: LVEDP. Left ventricular end-diastolic pressure . • Average (ra nge) .
ent in the 15 patients who were studied after both 6 months and 3 ~ years (Fig. 3). Aortic root angiography was performed on all 26 patients, 14 of whom had no or trivial insufficiency. In 7 the insufficiency was graded mild and in 5 it was considered moderate (Table IV). Comparing the degree of insufficiency seen after 6 months to that noted after 3 ~ years suggests that insufficiency has progressed in only 3 patients. None was clinically disabled as a result of the insufficiency. The lack of correlation between the clinical and angio-
graphic assessments of insufficiency supports the contention that catheter documentation of valve function is always necessary in any follow-up study. Pathology
Autopsy has been performed on all 5 patients who died. No gross or microscopic abnormalities were seen in the valves acquired from the 2 patients who died in the operating room. The valve examined 5 weeks after insertion (the patient died of septicemia) was macroscopically normal. A minimal thick-
The Journa l ol
224
Trimble et al.
Thoracic and Card iovascular Surgery
Fig. 4. Photomicrographs of the cusps of fascia lata aortic prostheses. Separate bundles of collagen fibers in the fascia are still obvious 5 weeks after insertion (A). Note fibrin material deposited on surface (arrow). Bundles of collagen fibers are no longer readily recognizable after the prosthesis has been in place 6 and 23 months (B and C) . Also, the original fascia has lost most of its cellularity. Its surfaces have been covered by an organized fibrin deposit that forms a pseudointima (P). The latter matures and tends to become more compact the longer the valve remains in the aortic area. In all instances, the segment of cusp nearest its free margin is uppermost. (Combined Masson trichrome-Verhoeff elastic stain; original mag- . nification x20. )
Table IV. Angiographic incompetence in 26 patients 3 ~ years after aortic valve replacement with fascia lata Grade
No. of patients
Trivial (0) Mild Moderate
14
7
5
ening, produced by a fine covering of translucent tissue, caused rounding of the free margins of the cusps and was more pronounced in their concavity. Microscopically, this covering was composed of a thin layer of organized fibrin (pseudointima) (Fig. 4, A). The underlying collagen bundles of the original fascia lata were totally acellular. The valve seen 6 months after implantation had been removed from the patient with a complicating Aspergillus infection involving the ascending aorta. The valve had not been invaded although a granulating mass of infected tissue lay within 1
em. of it. Its cusps were slightly thickened but nevertheless pliable, and the valve was totally competent. The pseudointimal covering had matured in comparison with the earlier valve and was thickest at the base of the cusps. The original fascia lata was relatively acellular, but the linear arrangement of the collagen bundles was still present (Fig. 4, B). The thickness of the cusps at 23 months was notably greatter than that seen at 5 weeks. The cusps were still pliable and the valve was totally competent. Microscopically, the changes were very similar to those noted at () months (Fig. 4, C). Discussion
The early failure of a frame-mounted fascia lata valve in the tricuspid position led to the prompt cessation of its use at this hospital. The fascia was found to be grossly thickened and distorted, changes which produced both stenosis and incompetence of the prosthesis.
Volume 68 Number 2 Augu,t. 1974
Aortic valve replacement with fascia lata
Although the alterations took longer to develop, mitral prostheses then showed similar changes, and we feared that a similar fate would overtake valves in the aortic position. However, progressive thickening does not appear to be a significant problem, and our late hemodynamic studies indicate that there is a fundamental difference between the behavior of fascia lata prostheses in the atrioventricular ring and that in the aortic ring. The pathological material available to us is limited, but our studies of it do suggest that the fascia itself is not viable and probably acts as a temporary support for the development of a pseudointimal covering. This covering extends over the whole fascial cusp, in contrast to the limited growth that has been described in homografts.' Perhaps it may offer longer support to the underlying collagen and prevent its ultimate breakdown. If this is so, the advantages of the fascial prosthesis may outweigh any disadvantages. Of particular concern was the late development of incompetence in 3 patients. In 2, the operative note specifically mentioned that one cusp was shorter than the others; it seems likely that the cause of valve dysfunction could be related to imperfections in the valve manufacture. On comparing the incidence of incompetence (whether mild or moderate) of valves inserted in the first 4 months with that of valves inserted in the second 4 months, we were surprised to find 10 out of 13 valves incompetent in the first period compared with 2 out of 13 in the second. This probably reflects our increasing familiarity with the manufacture of the valves and emphasizes the importance of perfection in their molding. The task was not relegated to a technical assistant, and the time added to the operative procedure by the necessity of the surgeon himself or a highly experienced assistant making the valve was not prohibitive. Although others" have suggested that the fascial valve is particularly prone to infection, our experience has not shown this. On the contrary, autopsy showed that the
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valve was not involved in 2 patients who died from infection. Hemodynamically, the fascial valve possesses the advantage of central-flow prosthetic valves. In particular, it performs very well in response to an increased cardiac output associated with exercise. Hemolysis was not seen in this series. Perhaps the greatest benefit, however, has been the total absence of thromboembolic episodes in spite of withholding anticoagulants. This has allowed patients to become entirely independent. In our opinion, they have made a better readjustment to life than the average patient with a prosthetic valve. Some of our patients had not seen a doctor after operation until they were recalled for review. The removal of a portion of fascia lata has not caused any problems with the patients apart from some minor discomfort on driving an automobile when the fascia was removed from the right thigh. For this reason we would suggest that the left thigh be used in order to leave the right leg completely normal for controlling the foot pedals of a car. In conclusion, our late experience with fascia lata for aortic valve replacement has proved most gratifying, both clinically and hemodynamically.
REFERENCES
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Senning, A.: Fascia Lata Replacement of Aortic Valves, J. THoRAC. CARDIOVASC. SURG. 54: 465, 1967. Ionescu, M. I., and Ross, D. N.: Heart Valve Replacement With Autologous Fascia Lata, Lancet 2: 335, 1969. Ionescu, M. I., Ross, D. N., Wooler, G. H., Deac, R., and Ray, R.: Replacement of Heart Valves With Autologous Fascia Lata: Surgical Technique, Br. J. Surg. 57: 437, 1970. Trimble, A. S., and Metni, F. N.: Heart Valve Replacement With Autologous Fascia Lata Using the Ionescu Technique, 1. THORAe. CARDIOVASC. SURG. 61: 385, 1971. Smith, J. c.: The Pathology of Human Aortic Valve Homografts, Thorax 22: 114, 1967. Dubiel, W. T., Johansson, L., and Willen, R.: Postoperative Changes in Autologous Fascia Lata Heart Valve Grafts: A Pathological Study, Ann. Thorac. Surg. 15: 140, 1973.