木村 達, 森安 史典, 川崎 俊彦, 染田 仁, 玉田 尚, 山下 幸孝, 小野 成樹, 梶村 幸三, 濱戸 教行, 内野 治人

Tohru KIMURA, Fuminori MORIYASU, Toshihiko KAWASAKI, Hitoshi SOMEDA, Takashi TAMADA, Yukitaka YAMASHITA, Shigeki ONO, Kozo KAJIMURA, Noriyuki HAMATO, Haruto UCHINO

京都大学部第一内科

The First Department of Medicine, Faculty of Medicine, Kyoto University

キーワード : Doppler method, transesophageal scan, azygos vein, vasopressin

The azygos venous blood flow–which is today measured invasively using the thermodilution method–has been accepted as an indicator of ascending collateral blood flow volume in patients with portal hypertension. Recently, developments in electronics have made it possible to use the transesophageal Doppler transducer for quantitative measurement of this flow. The present study was aimed at quantitatively evaluating the changes in azygos venous flow during vasopressin infusion using transesophageal Doppler ultrasound in patients with chronic liver diseases. Ten patients with liver cirrhosis (LC), and in whom esophageal varices had been demonstrated, and 7 with chronic hepatitis (CH) were studied. The transesophageal Doppler system (UST–936–5⁄SSD–350, Aloka Co. , Tokyo) had a frequency of 5 MHz and both color and FFT Doppler facilities. The azygos venous flow index (AzVFI), which was used as an indicator of the azygos venous blood flow, was calculated as (D²π⁄4)×(V_MAX⁄cosθ)×60 (cm³⁄min), where D is the diameter of the azygos vein from the B–mode, V_MAX is the time–average of the maximum velocity of the azygos blood flow from FFT spectra and θ is the angle between the Doppler beam and azygos vein. We also percutaneously estimated portal blood flow and common hepatic arterial flow using an ultrasonic Doppler duplex system, as described elsewhere. After obtaining baseline values, vasopressin was intravenously administered at a continuous rate of 0.3 unit⁄min for 10 minutes, and the same values were then obtained a second time.
The portal blood flow dropped by 58% both in the CH group (from 660±218 to 275±137 ml⁄min, mean±S. D. ) and in the LC group (677±164 to 286±77 ml⁄min). There was a tendency for common hepatic arterial flow to be slightly increased in the LC group. The LC group showed significantly higher baseline values than the CH group in both azygos vein diameter (7.5±1.4 vs 5.8±0.5 mm) and AzVFI (823±308 vs 413±160 cm³⁄min). The AzVFI significantly decreased during vasopressin infusion only in the LC group (823±308 to 700±293 cm³⁄min=15%). The results suggest that vasopressin's vasoconstrictive activity is selective in that only certain vesseles were affected.
Although this method is semi–invasive, it enables us, in combination with percutaneous Doppler methods, to assess the overall portal hemodynamics (including the ascending collateral vein) even on an outpatient basis.