FONTAN型手術施行患児におけるドプラガイドワイヤーを用いた肺動脈血流測定の臨床的有用性について

Assessment of Pulmonary Artery Flow Velocity using a Doppler Guidewire after the Fontan Operation

　modified FONTAN型手術を施行した術後患児5例に対し，ドプラガイドワイヤーによる肺動脈局所における直接的血流速度測定の臨床的有用性について検討した．全例ドブラガイドワイヤーにより肺動脈局所において良好かつ安定した血流波形が記録可能であった．得られた血流波形は全症例が2峰性パターンを示した．肺動脈造影所見では5例中3例の肺動脈形態には問題なかったが，左肺動脈の低形成により血流量に左右差を認めた例が1例，さらに左末梢肺動脈狭窄を認めた症例が1例存在した．このような症例に対し，ドプラガイドワイヤーを用いることで左右肺動脈血流量が測定でき，左右血流差を容易に評価可能であった．また未梢肺動脈狭窄病変に対して，カテーテルでの狭窄前後における圧較差の評価は困難であったが，ドブラガイドワイヤーにより鋭敏かつ定量的な評価が可能であった．

This study was performed to assess the value of the Doppler guide wire for the measurement of pulmonary blood flow after Fontan procedure. A Doppler guide wire was used in 5 patients who had undergone a modified Fontan procedure. A 15 MHz, 0.014 inch Dop-pier guide wire was introduced via the femoral vein and advanced into the pulmonary artery for recording pul-monary artery flow, average peak flow velocity (APV). maximum peak flow velocity (MPV), the systolic peak flow velocity integral (SPVi) and the diastolic peak flow velocity integral (DPVi). Quantitative pulmonary flow estimate (QPA) was calculated as the product of vessel cross-sectional area and mean velocity, with mean velocity estimated as 0.5×APV. Pulmonary angiogra-phy and cardiac catheterization were carried out simul-taneously in all patients.

In all patients, excellent and stable doppler signals were recorded in both pulmonary artery branches. The flow patterns in the pulmonary artery measured by the Doppler guide wire were biphasic. Three of the patients who underwent pulmonary angiography showed normal pulmonary angiography. However. peripheral pulmo-nary arterial stenosis was documented in one patient. and an imbalance of pulmonary blood flow was documented in another. In the case showing peripheral pulmonary arterial stenosis, APV and MPV of theproximal site of the stenotic lesion were 48cm/sec and 107cm/sec, respectively, and APV and MPV of the distal site of the stenotic lesion were 6.9cm/sec and 13 cm/see, respectively. The Doppler guide wire provided accurate and valuable information concerning the stenotic lesion. In the case showing an imbalance of pulmonary blood flow, the right pulmonary artery diam-eter was 10.0mm and the left pulmonary artery diame-ter was 4.7mm. In this case, QLPA/QRPA calculated by Doppler guide wire was 7: 93. The estimate of the imbalance of pulmonary blood flow was able to be made by using the Doppler guide wire.

Thus. direct measurement of pulmonary artery blood flow velocity in patients who have undergone a modified Fontan procedure is feasible by using a Doppler guide wire. The method could be useful in understanding the pathophysiology of pulmonary circulation and for the evaluation of hemodynamics.