Echocardiographic features of a stenotic

porcine aortic valve

Mohsin Alam; M.D. Sidney Goldstein, M.D. Detroit, Mich.

The echocardiographic features of porcine valve degeneration have recently been reported.’ These reports have conffined their descriptions to aortic insufficiency, mitral stenosis, and insufficiency occurring in the degenerating porcine xenograph. Although stenosis of the porcine valve in the aortic position has been noted to occur, the echocardiographic features were not described due to the inability to visualize the valve ade- quately. Subsequent to our initial reports, we have observed an additional patient with stenotic degeneration of the porcine xenograph in the aortic position that occurred 60 months after implantation.

Case history

D. D., a 39-year-old male, underwent an aortic valve replacement with a porcine xenograph (Hancock) valve. Six years later, he was seen again complaining of pressure-like chest pain and dyspnea on minimal exertion. He also com- plained of frequent light-headed spells, without syncope. There was no history of paroxysmal nocturnal dyspnea, fever, or chills.

Physical examination revealed a blood pressure of 120/80 mm. Hg, pulse 80/minute and regular. The carotid pulse upstroke was prolonged, and a systolic thrill was palpable in the second righit intercostal space. The aortic component of the second heart sound was diminished. A grade IV/VI systolic ejection murmur radiating to the carotid vessels and grade II/VI diastolic blowing murmur were present at the second right intercostal space and the lower left sternal border. The diastolic murmur had not been present on a physical examination performed a year previously, and the intensity of the systolic murmur had increased.

Pertinent laboratory studies including hemoglobin, platelet,

From the Division of Cardiovascular Medicine and the Department of Medicine, Henry Ford Hospital, Detroit, Mich.

Received for publication May 2,1979.

Accepted for publication Aug. 1, 1979.

Reprint requests: Mohsin Alam, M.D., Henry Ford Hospital, 2799 W. Grand Blvd., Detroit, Mich. 48202.

total and differential white blood count and blood cultures were all within normal limits. The electrocardiogram revealed left ventricular hypertrophy with strain pattern. Chest x-ray revealed left ventricular enlargement and on fluoroscopy, porcine valve calcification was noted. Cardiac catheterization revealed a peak porcine aortic valve gradient of 88 mm. Hg with calculated valve area of 0.53 square centimeters. Angiog- raphy revealed moderate porcine aortic valve insufficiency with normal coronary arteries.

An M-mode and a two-dimensional echocardiogram using conventional techniques and instrumentation (Smith-Kline Ekoline 20-A and Ekosector 1) were performed within one week of cardiac catheterization and porcine valve replacement surgery. Both modes of echocardiography revealed an increase in porcine cusp1 echoes (Fig. 1). The M-mode study, in addition, revealed high-frequency, low-amplitude systolic fluttering of the cusps. The opening of the valve could not be accurately measured on the M-mode study due to increased echoes from the thickened cusps. The systolic opening of the porcine cusps, however, was clearly visualized and was markedly reduced on the two-dimensional study (Fig. 1).

The gross examination of the porcine valve at the time of surgery revealed thickened and stenotic cusps with multiple calcific nodules and scarred retraction of the cusp margins (Fig. 2).

Discussion

M-mode e’chocardiography has been reported to be useful in evaluating a stenotic mitral por- cine valve.’ Although severe stenosis of a porcine valve has also been reported in the aortic posi- tion,’ the echocardiographic features of this enti- ty have not been reported. The increased cusp echoes in our patient were associated with thick- ening and calcification of the valve cusps, which was demonstrated at the time of surgery. Echo- cardiographic features of the stenotic porcine valve in the mitral position have shown a similar jincrease in cusp echoes with identical gross ana- tomic findings.’ As a result of increased cusp echoes, the porcine valve opening could not be clearly demonstrated by M-mode echocardiogra-

0002-8703/80/100517 + 03$00.30/001980 The C.V.Mosby Co. American Heart Journal 517

Fig. 1. M-mode and two-dimensional echocardiogram of the stenotic porcine aortic valve are shown. Left upper panel, increased cusp echoes with restricted cusp motion during systole are depicted. Right upper panel, after reducing the coarse gain, the high frequency low amplitude fluttering of the thickened cusps (6) are visualized. Lowerpane& a systolic frame of the two-dimensional echocardiogram is shown. Note the marked reduction (< 10 mm.) of the cusp opening. AR = aortic root; C = cusps; EKG = electrocardiogram; LA = left atrium; LV = left ventricle; S = ventricular septum; ST = porcine valve stents.

phy but was clearly reduced on the two-dimen- sional study. This is comparable to the previous reports in which the two-dimensional echocardi- ography, because of its greater spatial orienta- tion, was found to be more useful than the M-mode study in assessing the valve opening and stenosis of the native aortic valve.” The systohc opening of the porcine cusp, however, as with the native aortic valve, may be influenced by left ventricular stroke voBume.3 The left ventricular function and stroke volume were normal in our patient and would not account for the reduced cusp opening of the porcine valve.

The significance of the systolic fluttering noted on the M-mode study of our patient cannot be determined. Similar flutter has been reported in a normal native aortic valvej4 but has not been observed in a normally functioning porcine aortic va1ve.j It is possible that the systohc flutter may be a normal finding which has not yet been reported in the relatively small number of echo-

cardiographic reports dealing with the functional- ly normal porcine bioprosthesis in the aortic position. Another possible explanation of the systolic flutter may be as a result of turbulence of

ow across the stenotic and thickened porcine cusps. Further studies are needed in this area before firm conclusions can be drawn,

The etiology of porcine valve stenosis is not exactly clear. Most hkely it is a result of a degenerative process similar to that previously reported by light and electron microscopic study of these valves.“. i

In conclusion, both modes of echocardiography are of value in evaluating stenosis of the porcine aortic valve, a condition which may be amenable to valve replacement surgery.

ummary

M-mode and two-dimensional echocardio- graphic features are reported in a patient who developed severe stenosis of a porcine xenograph

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ECHO features of stenotic porcine valve

Fig. 2. This figure shows the gross appearance of the stenotic porcine valve. The cusps are thickened with multiple calcific nodules and retracted cusp margins.

valve implanted in the aortic position. The pre- sence of increased cusp echoes along with reduced cusp opening was the most consistent echocardio- graphic find-kg in this patient. The clinical and the echocardiographic findings were subsequently confirmed by cardiac catheterization and sur- gery.

4.

5.

REFERENCES

1. Alam, M., Madrazo, A. C., Magilligan, D. J., and Gold- stein, S.: M-mode and two-dimensional echocardiograph- ic features of porcine valve dysfunction, Am. J. Cardiol. 43:502, 1979.

2. Weyman, A. E., Dillon, J. C., Feigenbaum, H., and Chang, S.: Cross-sectional echocardiography in assessing the severity of valvular aortic stenosis, Circulation 52:828, 1975.

6.

7.

Harrison, D. C., and Popp, R. L.: Echocardiographic evaluation of the stent mounted aortic bio-prosthetic valve in the mitral position. In vitro and in vivo studies, Circulation 54:91, 1976. Pinto, E. R., Damani, P. M., Sternberg, C. N., and Liedtke, A. J.: Fine flutterings of the aortic valve as demonstrated hy aortic valve echocardiograms, AM. HEART J. 95:807,1978. Chandraratna, P. A. N., and San Pedro, S. B.: Echocar- diographic features of the normal and malfunctioning porcine xenograft valve, AM. HEART J. 95:548, 1978. Fishbein. M. C.. Gissen. S. A., Collins, J. J.. Barsamian. E. M., and ‘Cc’hn,’ L. H.: ‘Pathologic findings after cardiac valve replacement with glutaraldehyde-fixed porcine valves, Am. J. Cardiol. 40:331, 1977. Ferrans, V. J., Spray, T. L., Billingham, M. E., and Roberts, W. C.: Structural changes in glutaraldehyde- treated porcine hetrografts used as substitute cardiac valves. Transmission and scanning electron microscopic observations in twelve patients, Am. J. Cardiol. 41:1159,

3. Horowitz, M. S., Tecklenberg, P. L., Goodman, D. J., 1978.

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