宮沢 総介, 鈴木 茂, 佐々木 達海, 水野 朝敏, 望月 吉彦, 高安 英樹, 新井 達太

Sosuke MIYAZAWA, Shigeru SUZUKI, Tatsuumi SASAKI, Asatoshi MIZUNO, Yoshihiko MOCHIZUKI, Hideki TAKAYASU, Tatsuta ARAI

東京慈恵会医科大学　心臓血管外科

The Jikei University School of Med., Department of Cardiovascular Surgery

キーワード : Ionescu-Shiley pericardial xenograft, 2-Dimensional echocardiography, Pulsed Doppler echocardiography

Using the Ionescu-Shiley pericardial xenografts (ISPX), mitral valve replacement was performed on 64 cases during a period of 1980-1984. Follow-up studies were made on 48 0f these cases and observed for degenerative changes on ISPX using 2-dimensional and ultrasonic Doppler methods. The results revealed the followings:
1. Incidence of obvious cuspal thickening or calcification was noted on 4, 12, 38, 47 and 58% of cases for 3, 4, 5, 6 and 7 years, respectively.
2. Including minute changes, such as a slight increase of echo brightness, the rate of detection of change was as high as 15, 25, 57, 65 and 83% for 2, 3, 4, 5, 6 and 7 years, respectively.
3. Maximum velocity at the left ventricular inflow tract was 1.0-1.5 m/s and remain unchanged so long as ISPX was functioning normally. In the group of patients with normally functioning ISPXs, pressure half time (PHT) was gradually prolonged (91 msec, at 1 year-112 msec, at 6 year) year by year. In the patient with stenotic ISPX, PHT was prolonged to 210 msec. Once regurgitation or stenosis occurred, the velocity of flow become greater and in those cases which reached 2 m/s, it required another replacement.
4. The malfunctioning ISPXs were divided into two groups by 2-D echocardiography, one with cuspal thickening and calcification and another without these degenerative changes but with a large tear. In the former, multiple small tears were observed on re-operation. In cases with this type of valve, elective surgery was possible. In the later type valves, a large tear was observed on re-operation. In cases having this type valve, emergency re-operation was required.
Degenerative changes of the extracted prosthetic valves well reflected findings of the 2-demensional echocardiographic observation, especially the commissural calcification. But, diagnosis of small tears with a length of 5-6 mm was difficult.
Of the 48 cases, 9 cases (19%) showed valvular dysfunction in echocardiographic examinations. However, even those cases which showed no such dysfunction, proved that ISPX valve are subjected to high rate of cuspal degeneration. For prosthetic valve replacement by ISPX, both, frequent examination by means of echocardiography and Doppler method and careful observation of the patients course are necessary.