Late Thrombosis of the Aortic Bjork-Shiley Prosthesis

Late Thrombosis of the Aortic Biork-Shiley Prosthesis· Its Clinical Recognition and Management Javier Fernandez, M.D., F.C.C.P.;oo Aaron Samuel, M.D.;t Sing Sang Yang, M.D.;* Sumathisena, M.D.;§ Alden Gooch, M.D.;II Vladir Maranhao, M.D., F.C.C.P.;1f Gerald M. Lemole, M.D., F.C.C.P.;#: and Harry Goldberg, M.D., F.C.C.P.§§

Seven cases of massive thrombosis of an aortic BjorkShiley prosthesis were encountered among 433 valvular implants. Four patients died before treatment could be instituted, and three underwent repeat surgery successfully. Anticoagulation therapy was probably weD maintained in four, and poorly maintained in three patients. These cases illustrated the need for a high index of suspicion and prompt recognition of this compUcation in pa-

In

1969, Bjork' introduced a new central-How aortic disk prosthesis, and favorable initial results with this valve have been reported;2-7 however, in spite of employing anticoagulation therapy, we have encountered seven late failures of the Bjork-Shiley valve due to massive thrombosis in 433 patients with such valves. Four died of this complication before surgery could be performed, and three underwent surgery successfully. Although two of these cases were mentioned elsewhere,3 a total of seven cases are described herein to stress the importance of early diagnosis and prompt surgical treatment. CASE REPORTS CASE

1

A 69-year-old woman underwent aortic valvular replacement with a No. 21 Bjork-Shiley prosthetic valve with a o From

the Departments of Cardiothoracic Surgery and Cardiology, Deborah Heart and Lung Center, Browns Mills, NJ. Presented at the 41st Annual Scientific Assembly, American College of Chest Physicians, Anaheim, Calif, Oct 29, 1975. 00 Associate Chief, Cardiothoracic Surgery. tSenior Surgical Fellow. tDirector, Cardiac Noninvasive Laboratory. §Associate Cardiologist. II Director, Clinical Cardiology. ~Director, Cardiac Catheterization Laboratory. #Chief, Cardiothoracic Surgery. §§Chief, Department of Cardiology. Manuscript received November 6; revision accepted February 16. Reprint requests: Dr. Fernandez, Deborah Hospital, Browns Mills, New Jersey 08015

12 FERNANDEZ ET AL

tients with aortic Bjork-ShUey prostheses. The diagnosis of massive thrombosis should be suspected with the rapid onset of (1) signs of congestive heart failure, (2) absence or attenuation of valvular cUcks, (3) aortic regurgitation, or (4) hemolytic anemia. Salvage of these patients requires emergency replacement of the thrombosed prosthesis or removal of the thrombus.

Delrin disk II II in July 1970. On Feb 14, 1973, she was readmitted with a history of progressive shortness of breath, easy fatigability, and anemia of two months' duration. Values for her prothrombin content calculated from the prothrombin times were near the 30-percent level during her clinic visits and at the time of her admission. The normal clicking sounds of the prosthesis could not be heard, but a loud systolic ejection murmur in the aortic area and a diastolic decrescendo murmur along the left sternal border were detected (Fig 1). A malfunctioning aortic valvular prosthesis or paravalvular leak was suspected. Two days after the patient's admission, a thrombosed prosthesis was excised and replaced with another No. 21 Bjork-Shiley prosthesis, this time with a Pyrolite disk. The patient is now alive and well 31 months after her second operation, with normal aortic prosthetic sounds (Fig 2). CASE

2

A 64-year-old man with aortic stenosis underwent successful aortic valvular replacement with a No. 21 Bjork-Shiley prosthesis with a Pyrolite disk in January 1972. Ten months after the surgery, he developed shortness of breath and chest pains. The patient did not receive adequate anticoagulation therapy, although he was being treated with warfarin ( Coumadin). On admission, his prothrombin content calculated from the prothrombin time was 58 percent. The clicks of the prosthesis were absent. There was a new systolic murmur at the aortic area and a diastolic munnur at the left sternal border. On the second day after admission, the patient suddenly died. Autopsy disclosed an organized thrombus covering the prosthetic valve on both surfaces. CASE

3

A 49-year-old woman underwent mitral valvular replacement with a Beall prosthetic valve and aortic valvular re-

II II Shiley Laboratories, Santa Ana, Calif. CHEST, 70: 1, JULY, 1976

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of the follow-up visits ranged from 20 percent to 30 percent. In February of 1974, the patient was readmitted because of severe congestive heart failure of two weeks' duration. The mitral prmthetic clicks were distinctly heard, but the aortic valvular clicks were described as "decreased." A loud systolic aortic murmur and a diastolic murmur along the left sternal border were easily detected. A chest x-ray fUm revealed signs of pulmonary edema. The patient became comatose after two episodes of cardiac arrest and died on the morning of the third day of hospitalization. Autopsy revealed the aortic prosthesis to be partly open, and the disk was firmly fixed with a well-organized thrombus. CASE 4

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1 1 1 '1111 1111 FIGURE 1. Phonocardiogram recorded at fourth intercostal space at left sternal border before replacement of BjorkShiley prosthesis (case 1). Note diminished opening click (OC), absence of closing click, loud ejection systolic murmur (SM), and faint early diastolic murmur (DM). SI, First heart sound. placement with a No. 27 Bjork-Shiley prosthesis with a Pyrolite disk in February 1972. Values for her prothrombin content calculated from the prothrombin times during many

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CHEST, 70: 1, JULY, 1976

A 71-year-old woman underwent aortic valvular replacement with a No. 19 Bjork-Shiley valve with a Pyrolite disk in April 1972. She was receiving warfarin (Coumadin) regularly under her physician's supervision following surgery. Values for her prothrombin content based upon the prothrombin times were within the therapeutic range of 20 percent to 30 percent on the follow-up visits. Two years after the operation, the patient developed shortness of breath of one week's duration in association with jaundice and anemia (hemoglobin level, 9.9 gm/l00 ml; and hematocrit reading, 28 percent). On admission, her prothrombin time was 19 seconds (or 32 percent). Only the opening click was faintly heard. A loud systolic murmur was audible at the aortic area, and an early blowing diastolic murmur was heard along the left sternal border. A few hours after admission, the patient suddenly developed cardiac arrest. At autopsy the pryolite disk was found to be covered in half of its surfaces by an organized thrombus occluding mostly the disk's small aperture (Fig 3 and 4). CASE 5 A 67-year-old woman underwent aortic valvular replacement with a No. 25 Bjork-Shiley prosthesis with a Pyrolite disk in May 1972. Values for her prothrombin content calculated from the prothrombin times were maintained between 20 percent· and 30 percent while the patient was receiving warfarin (Coumadin) regularly. On April 29, 1974, she became dyspneic rather abruptly and was treated for pulmonary edema. At this time, her valvular clicks could not be detected. There was a loud systolic murmur in the aortic area and a diastolic murmur along the left sternal border. The patient became azotemic and very lethargic. Nine days after admission, she suddenly died. Autopsy revealed an extensive organized thrombus covering both sides of the aortic prosthesis. CASE 6 This 55-year-old woman underwent mitral commissurotomy and aortic valvular replacement with a No. 23 Bjork-Shiley prosthesis with a Pryolite disk in April 1972. In October of 1974, she developed acute pulmonary edema after three weeks of progressive dyspnea. Her anticoagulation therapy was considered to be inadequate. Her prothrombin content calculated from the prothrombin times fluctuated between 50 percent and 70 percent. A loud systolic aortic murmur and a new diastolic blowing murmur along the left sternal border were detected. The clicking sounds of the prosthesis were not audible. At surgery two hours after admission, a thrombus firmly adherent around the smaller aperture of the aortic prosthesis wa~ completely removed (Fig 5). The protruding septum might have caused turbu-

LATE THROMBOSIS OF AORTIC BJORK·SHILEY PROSTHESIS 13

THROMBUS

L. VENTRICLE

MITRAL VALVE 5, Diagram of findings in case 6. Thrombosis of Bjork-Shiley valve around its smaller opening. Hypertrophied ventricular septum may have contributed to turbulence and formation of thrombus. Inset, After thrombectomy and debridement, disk was rotated 180·, placing smaller aperture away from septum to decrease turbulence. FIGURE

lence and thereby contributed to the thrombosis; therefore, the disk was rotated 180·. The patient is now doing well one year after her reoperation. CASE

3. Organized thrombus covering disk of aortic BjorkShiley prosthesis, as seen from aortic aspect (case 4). FIGURE

7

A 56-year-old woman underwent aortic valvular replacement with a No. 23 Bjork-Shiley prosthesis with a Pyrolite disk and mitral valvular replacement with a large Beall prosthesis in October 1973. Sixteen months after surgery, she developed rapidly progressing congestive heart failure. There was a loud systolic murmur in the aortic area and a new diastolic blowing murmur best heard along the left sternal border. The clicking sounds of the prosthesis were absent. The patient's anticoagulation therapy was inadequate prior to the emergency operation. Her prothrombin content calculated from the prothrombin times ranged from 46 percent to 90 percent. At surgery three hours after admission, a thromhosed aortic prosthesis was replaced with another No. 23 Bjork-Shiley valve. The patient has again resumed normal activities eight months after her second operation. DISCUSSION

FIGURE 4. Or~anized thromhus coverin~ disk of aortic BjorkShiley prosthesis, as seen from the ventricular side (case 4). Note that thrombus is localized mainly around smaller aperture.

14 FERNANDEZ ET Al

Clinical and functional results with the use of the Bjork-Shiley aortic prosthesis have been encouraging. 2-9 Despite the excellent hemodynamic characteristics of this valve, the lethal complication of thrombosislo.1 3 may occur even in the presence of seemingly adequate anticoagulation therapy. In all of our seven cases, the disk was found to be fixed by the thrombus at a very small angle (15°), causing stenosis and regurgitation. All patients in this series had good initial clinical results after the initial valve replacement; however, without any warning, the patients became symptomatic late in the postoperative period, an average of 24 months after surgery (Table 1). In most cases the duration of the symptoms before the patient reentered the hospital was quite short, an CHEST, 70: 1, JULY, 1976

Table l--Summary 01 Clinieal Material Date of Valvular Replacement

Interval from Duration of Surgery to Symptoms before Readmission (mo) Readmission

Interval from Readmission to Surgery or Death

Case, Age (yr), Sex

Original Valvular Disease·

1,69, F

AS, AR, calcific

7/23/70

32

60 days

2 days

2,64, M

AS, calcific

1/4/72

10

4 days

2 days

3,49, F

AS, AR, MR

2/2/72

24

2 weeks

2 days

4,71, F

AS, AR, calcific

4/4/72

25

1 week

7hr

5,67, F

AS,AR

5/25/72

24

5 days

9 days

6,55, F

AS, AR, MS

4/28/72

36

3 weeks

2hr

7,56, F

AS, AR, MS, MR

10/15/73

16

3 weeks

3hr

-AS, Aortic stenosis; AR, aortic regurgitation; MR, mitral regurgitation; and MS, mitral stenosis.

average of 19 days. One of the survivors experienced symptoms for two months. The clinical deterioration of the patient's condition in the hospital was rather rapid, varying from a few hours to nine days until death or operation. Among the survivors, one underwent surgery on the second day of hospitalization, and two patients underwent surgery at two and three hours after admission, respectively. The most common symptom was dyspnea on effort and paroxysmal nocturnal dyspnea (Table 2). In three patients, dyspnea was associated with chest pain which was of a nonspecific nature. All patients had acute symptoms at the time of admission, showing various degrees of respiratory distress. Edema of

the ankles was present in all. Severe hemolytic anemia associated with clinical jaundice was present in two patients. The most common physical sign was the absence of the normal clicking sounds of the prosthesis and the appearance of a new diastolic murmur of aortic regurgitation. It is not unusual to hear a soft diastolic murmur in many patients with properly functioning Bjork-Shiley valves, since this valve normally produces a slight degree of valvular leak.. In addition, a loud systolic ejection murmur (Fig 1) was often heard. This is an unusual feature with a properly functioning Bjork-Shiley prosthesis, although a soft systolic murmur is quite common.

Table 2--Clinical Findin•• and Treatmen' of Set1en Patien'••i,h Thrombo.ed Bjiirlc-Slailey Pro.me.e.

Mode of Onset Physical Signs··

Anticoagulative Laboratory Chest Findings Film Therapyt

1 SOB, jaundice

Gradual Absent clicks, SM,DM

Adequate

2 SOB, chest pain

Abrupt Absent clicks, SM,DM

Inadequate

3 CHF

Abrupt Faint aortic clicks, Adequate SM,DM

Case Symptoms·

4

CHF, jaundice, Abrupt Faint opening chest pain click, SM, DM

Severe anemia

Azotemia

Severe anemia Azotemia

Abrupt Absent clicks, SM,DM

Adequate

6 SOB

Gradual Absent clicks, SM,DM

Inadequate

7 SOB

Gradual Absent clicks, SM,DM

Inadequate

Result

Replacement of aortic valve

Alive

Died suddenly; second hospital day

Adequate

5 SOB, chest pain, lethargy

Treatment

Died suddenly; second hospital day

Pulmonary edema

Shock and arrest 7 hr after admission Pulmonary edema

Died, ninth hospital day

Pulmonary Thrombectomy Alive and d~bridement edema of prosthesis Replacement of aortic valve

Alive

·SOB, Shortness of breath; and CHF, congestive heart failure. ··SM, Systolic murmur; and DM, diastolic murmur. t Based on serial determinations of prothrombin time at outpatient visits.

CHEST, 70: 1, JULY, 1976

LATE THROMBOSIS OF AORTIC BJORK-SHILEY PROSTHESIS 15

The data presented here would indicate that the diagnosis of malfunctioning aortic Bjork-Shiley prosthesis should be suspected in any postoperative patient who was asymptomatic initially but suddenly developed symptoms and signs of heart" failure with or without hemolytic anemia. If, in addition, there is a loss or attenuation of the valvular clicks or the appearance of a new or louder diastolic munnur, the need for surgery is clear. Although paravalvular aortic leaks cannot be clearly differentiated, they also require early surgical intervention. Echocardiographic studies and emergency aortic-root arteriographic studies may be of value, as pointed out by Ben Zvi et al. I3 Echocardiographic studies may demonstrate the absence of motion of the prosthetic disk, but negative findings do not exclude the presence of thrombotic occlusion. When thrombosis of the prosthesis is expected, repeat surgery should be performed on an emergency basis. Salvage of such patients is possible, as in cases 1, 6, and 7, and the case reported by Bjork and Henze. II The procedure of choice consists of removal of the obstructed prosthesis and reinsertion of a new prosthetic valve, or thrombectomy and debridement of the prosthesis until perfect restoration of the mobility of the disk is obtained. Poor control of anticoagulation therapy could be considered a factor in massive clotting of a prosthetic valve. In the cases presented here, anticoagulation therapy was inadequate in three patients, as in the two cases reported by Bjork and Henze ll and in six of the seven cases recently reported by Ben-Zvi et aI. I3 The finding of four patients apparently with well-maintained anticoagulation therapy does not necessarily mean that their prothrombin times were within the therapeutic range throughout their postoperative course. Although we recommend maintaining the prothrombin times between 20 and 30 seconds with administration of warfarin sodium, the level of anticoagulation therapy varies widely in our experience, depending upon the private physician's decisions and the vagaries inherent in the use of this drug. Flow studies of the Bjork-Shiley valve4 •7 have demonstrated laminar How and practically no stagnation at any point; however, other reports 10,12 suggest that the main factor for local thrombosis is the formation of eddying currents around the small aperture of the valve where the excursion of the disk is minimal. Gross examination of the specimens from our cases showed that the thrombus was predominantly localized on both sides of the small aperture of the valve, as if it originated from this point and then gradually spread over the remaining part of the disk. For this reason the smaller aperture of the

16 FERNANDEZ ET AL

valve is now placed posteriorly towards the mitral valve in order to minimize the turbulence that might occur if it is placed in relation to the septum as depicted in Figure 5. Whatever the factors are that lead to local thrombosis, it seems that this complication has been rare, with an incidence of 2 percent (seven cases) in our series of 433 Bjork-Shiley prosthetic valvular insertions with a follow-up period of up to five years. Messmer et al9 reported a 2-percent incidence among 460 aortic valvular replacements with the Bjork-Shiley valve. Nevertheless, it is clear that no patient with a prosthetic device is totally free of the possibility of thromboembolic complications, and we concur with Cokkinos et aJ12 that a search for prosthetic cardiac valves with less thrombogenicity should continue. REFERENCES

1 Bjork VO: A new central-flow tilting-disc valve prosthesis: One year's clinical experience with 103 patients. J Thorac Cardiovasc Surg 60:355-374, 1970 2 Fernandez ], Maranhao V, Gooch AS, et al: The BjorkShiley prosthesis: A significant advance in aortic valve replacement. Ann Thorac Surg 14:527-538, 1972 3 Fernandez J, Morse D, Maranhao V, et al: Results of use of the Pyrolytic carbon tilting disc Bjork-Shiley aortic prosthesis. Chest 65:640-645, 1974 4 Bjork VO, Holmgren A, Olin C, et aI: Clinical and hemodynamic results of aortic valve replacement with the Bjork-Shiley tilting disc valve prosthesis. Scand ] Thorac Cardiovasc Surg 5:177-191, 1971 5 Bjork VO, Henze A, Holmgren A: More than five years' experience with the Bjork-Shiley tilting disc valve in isolated aortic valvular disease. Presented at the 54th annual meeting of the American Association for Thoracic Surgery, Las Vegas, Nev, April 22-24, 1974 6 Lepley OJ, Reuben CF, Flemma RJ, et al: Experience with the Bjork-Shiley prosthetic valve. Circulation 48: (suppI3) :11151-11155, 1973 7 Messmer BJ, Hallman GL, Liotta 0, et al: Aortic valve replacement: New techniques, hydrodynamics, and clinical results. Surgery 68: 1026-1037, 1970 8 Nitter-Hauge S, Hall KV, Froysaker T, et al: Aortic valve replacement: One-year results with Ullehei-Kaster and Bjork-Shiley prosthesis: A comparative clinical study. Am Heart J 88:23-27, 1974 9 Messmer BJ, Okies JE, Hallman GL, et al: Aortic valve replacement: Two years' experience with the Bjork-Shiley tilting-disc prosthesis. Surgery 72:772-779, 1972 10 Bozer AY, Karamehmetoglu A: Thrombosis encountered with Bjork-Shiley prosthesis. J Cardiovasc Surg 13:141143, 1972 11 Bjork VO, Henze A: Encapsulation of the Bjork-Shiley aortic disc valve prosthesis caused by the lack of anticoagulation treatment. Scand J Thorac Cardiovasc Surg 7:17-20,1973 12 Cokkinos OV, Voridis E, Bakoulas G, et al: Thrombosis of two high-flow prosthetic valves. J Thorac Cardiovasc Surg 62:947-949, 1971 13 Ben-Zvi J, Hildner FJ, Chandraratna PA, et al: Thrombosis on Bjork-Shiley aortic prosthesis. Am J Cardio] 34:538-544, 1974

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