Hozumi T, Yoshikawa J, Yoshida K, Akasaka T
Department of Cardiology, Kobe General Hospital, Japan.
J Am Soc Echocardiogr. 1995 Sep-Oct;8(5 Pt 1):595-601. doi: 10.1016/s0894-7317(05)80372-4.
Application of the continuity equation to Doppler catheter measurement of quantitative coronary flow velocity has been reported recently to be one of the accurate methods to evaluate mild to moderate coronary stenosis. This method, however, has not been validated in moderate to severe coronary stenosis. Furthermore, the ratio of prestenotic velocity/stenotic velocity may be influenced by side branches proximal to moderate to severe stenosis. Therefore we designed this study to evaluate the accuracy of the continuity equation method in the assessment of moderate to severe stenosis by an 0.018-inch (0.46 mm) Doppler guide wire (12 MHz) and the influence of a side branch on estimation of stenotic severity. Doppler spectra were recorded in the straight rigid tubes (4 mm diameter) with different severities of stenosis (50%, 62.5%, and 75% diameter stenosis) without a side branch with a Doppler guide wire. By the continuity equation, percent diameter stenosis was calculated from the proximal/stenotic and distal/stenotic velocity ratios in each model at different flow rates. In the model of 75% diameter stenosis with a side branch (1 mm diameter) proximal to the stenosis and the model of 75% diameter stenosis with a side branch (1 mm diameter) distal to the stenosis, percent diameter stenosis was calculated by the same method. Percent diameter stenosis derived from the proximal/stenotic velocity ratio in each model was in agreement with the true severity of stenosis in each model without a side branch (48% +/- 1%, 62% +/- 1%, and 75% +/- 1%, respectively). Percent diameter stenosis from the distal/stenotic velocity ratio was also in agreement with the true severity of stenosis in each model without a side branch (48% +/- 3%, 61% +/- 1%, and 75% +/- 1% respectively). In the model of 75% diameter stenosis with a side branch proximal to the stenotic site, however, percent diameter stenosis derived from the proximal/stenotic velocity ratio was underestimated compared with the real stenosis and significantly smaller than that derived from the distal/stenotic velocity ratio (65% +/- 1% versus 74% +/- 1%; p < 0.001). On the other hand, in the model of 75% diameter stenosis with a side branch distal to the stenotic site, the percent diameter stenosis derived from both the proximal/stenotic and distal/stenotic velocity ratios was in agreement with that derived from the distal/stenotic velocity ratio (75% +/- 2% and 77% +/- 1%). In the experimental models the estimation of stenotic severity by a Doppler guide wire is accurate even in moderate to severe stenosis unless a side branch exists just proximal to the stenosis. However, the distal/stenotic velocity ratio is applicable even if a side branch exists. This suggests that severity of stenosis derived from the distal/stenotic velocity ratio may be more useful than that from the proximal stenotic velocity ratio in human coronary stenosis with side branches.
连续性方程应用于多普勒导管定量测量冠状动脉血流速度，最近已被报道是评估轻至中度冠状动脉狭窄的准确方法之一。然而，该方法尚未在中至重度冠状动脉狭窄中得到验证。此外，狭窄前速度/狭窄处速度之比可能受中至重度狭窄近端侧支的影响。因此，我们设计了本研究，以评估用0.018英寸（0.46毫米）多普勒导丝（12兆赫）通过连续性方程法评估中至重度狭窄的准确性，以及侧支对狭窄严重程度估计的影响。使用多普勒导丝在无侧支的不同狭窄严重程度（直径狭窄50%、62.5%和75%）的直硬管（直径4毫米）中记录多普勒频谱。通过连续性方程，根据每个模型在不同流速下的近端/狭窄处和远端/狭窄处速度之比计算直径狭窄百分比。在狭窄近端有侧支（直径1毫米）的75%直径狭窄模型和狭窄远端有侧支（直径1毫米）的75%直径狭窄模型中，用相同方法计算直径狭窄百分比。每个无侧支模型中由近端/狭窄处速度之比得出的直径狭窄百分比与每个模型中狭窄的真实严重程度相符（分别为48%±1%、62%±1%和75%±1%）。每个无侧支模型中由远端/狭窄处速度之比得出的直径狭窄百分比也与狭窄的真实严重程度相符（分别为48%±3%、61%±1%和75%±1%）。然而，在狭窄部位近端有侧支的75%直径狭窄模型中，由近端/狭窄处速度之比得出的直径狭窄百分比与实际狭窄相比被低估，且明显小于由远端/狭窄处速度之比得出的结果（65%±1%对74%±1%；p<0.0
