Montealegre-Gallegos Mario, Matyal Robina, Khabbaz Kamal R, Owais Khurram, Maslow Andrew, Hess Philip, Mahmood Feroze
From the Departments of *Anesthesia, Critical Care and Pain Medicine, and †Surgery, Division of Cardiac Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts; and ‡Department of Anesthesiology, Cardiology, and Surgery, Rhode Island Hospital, Providence, Rhode Island.
Anesth Analg. 2016 Aug;123(2):290-6. doi: 10.1213/ANE.0000000000001439.
The left ventricular outflow tract (LVOT) is a composite of adjoining structures; therefore, a circular or elliptical shape at one point may not represent its entire structure. The purpose of this study was to evaluate the presence of heterogeneity in the LVOT.
Patients with normal valvular and ventricular function undergoing elective coronary revascularization surgery were included in the study. Intraoperative R-wave gated 3-dimensional (3D) transesophageal echocardiographic imaging of the LVOT was performed at end-systole, with the midesophageal long axis as the reference view. Acquired data were analyzed with the Philips Q-Lab software with multiplanar reformatting in the sagittal (minor axis), transverse (major axis), and coronal (cross-sectional area by planimetry) views of the LVOT. These measurements were made on the left ventricular side or proximal LVOT, aortic side, or distal LVOT and mid-LVOT.
Fifty patients were included in the study. The LVOT minor (sagittal) axis dimension did not differ across the mid-LVOT, proximal LVOT, and distal LVOT (P = .11). The major axis diameter of LVOT differed among the 3 regions of the LVOT (P < .001). A difference in major axis diameter was observed between the proximal and the distal LVOT (median difference of 0.39 cm; Bonferroni-adjusted 95% confidence interval [CI] of the difference = 0.31-0.48 cm; Bonferroni-adjusted P < .001). Planimetry of the LVOT area differed significantly (P < .001) between the regions analyzed, and we found a difference between the distal and the proximal LVOT (median difference = 0.65 cm, Bonferroni-adjusted 95% CI of the difference = 0.44-0.88 cm, Bonferroni-adjusted P < .001). The LVOT area calculated from minor axis diameter differed significantly from the area obtained by planimetry (P < .001).
There was heterogeneity in the major axis diameter and cross-sectional area for the different regions of the LVOT. The distal LVOT (aortic side) was more circular, whereas the proximal LVOT (left ventricular side) was more elliptical in shape. This change in shape from circular to elliptical was accounted for by a difference in the major axis diameter from proximal to distal LVOT and a relatively similar minor axis diameter. Although the clinical significance of this finding is unknown, the assumption of a uniform structure of LVOT is incorrect. Three-dimensional imaging may be useful for assessing the LVOT shape and size at a specific region of interest.
左心室流出道（LVOT）是相邻结构的复合体；因此，某一点处的圆形或椭圆形可能并不代表其整个结构。本研究的目的是评估LVOT中异质性的存在情况。
纳入接受择期冠状动脉血运重建手术且瓣膜和心室功能正常的患者。在收缩末期，以食管中段长轴为参考视图，对LVOT进行术中R波门控三维（3D）经食管超声心动图成像。获取的数据使用飞利浦Q-Lab软件进行分析，在LVOT的矢状面（短轴）、横断面（长轴）和冠状面（通过面积测量法测量横截面积）视图中进行多平面重新格式化。这些测量在左心室侧或LVOT近端、主动脉侧或LVOT远端以及LVOT中部进行。
本研究共纳入50例患者。LVOT短轴（矢状面）尺寸在LVOT中部、近端和远端之间无差异（P = 0.11）。LVOT长轴直径在LVOT的三个区域之间存在差异（P < 0.001）。在LVOT近端和远端之间观察到长轴直径存在差异（中位数差异为0.39 cm；差异的Bonferroni校正95%置信区间[CI] = 0.31 - 0.48 cm；Bonferroni校正P < 0.001）。LVOT面积的面积测量法在分析的区域之间存在显著差异（P < 0.001），并且我们发现LVOT远端和近端之间存在差异（中位数差异 = 0.65 cm，差异的Bonferroni校正95% CI = 0.44 - 0.88 cm，Bonferroni校正P < 0.001）。根据短轴直径计算的LVOT面积与通过面积测量法获得的面积存在显著差异（P < 0.001）。
LVOT不同区域的长轴直径和横截面积存在异质性。LVOT远端（主动脉侧）更接近圆形，而LVOT近端（左心室侧）形状更接近椭圆形。这种从圆形到椭圆形的形状变化是由LVOT近端到远端长轴直径的差异以及相对相似的短轴直径所导致的。尽管这一发现的临床意义尚不清楚，但认为LVOT结构均匀的假设是不正确的。三维成像可能有助于评估感兴趣的特定区域的LVOT形状和大小。
