Department of Cardiac Surgery, Medical University of Innsbruck, Innsbruck, Austria.
Interact Cardiovasc Thorac Surg. 2021 May 10;32(5):711-718. doi: 10.1093/icvts/ivaa328.
Transit-time flow measurement is a recognized method for graft evaluation in coronary surgery. However, single flow measurement has been associated with a low specificity for detecting graft dysfunction. The goal of this study was to assess the value of transit-time flow measurement for assessing in situ internal mammary artery grafts during non-existent native coronary circulation and the relevance of collateral blood flow in target vessels.
Between 2014 and 2018, a total of 134 patients undergoing on-pump coronary artery bypass grafting were evaluated using transit-time flow measurement. We analysed 111 single left internal mammary artery and 57 single right internal mammary artery bypasses. Correlations between coronary relevant parameters were calculated using Spearman's ρ coefficient. Risk factors for decreased flow with an arrested heart (FAH) <30 ml/min and an increased pulsatility index (PI) >3.0 as well as flow reduction >30% were calculated.
FAH correlated with the diameter of the target vessel (Spearman's ρ = 0.32; P < 0.001), the amount of blood distribution (Spearman's ρ = 0.34; P < 0.001), the PI (Spearman's ρ = 0.19; P = 0.019) and the degree of stenosis (Spearman's ρ = -0.17; P = 0.042). The percentage of flow change was found to correlate with the PI (Spearman's ρ = -0.47; P < 0.0001), the degree of stenosis (Spearman's ρ = 0.42; P < 0.001), the diameter of the target vessel (Spearman's ρ = -0.22; P = 0.008) and the area of blood distribution (Spearman's ρ = -0.19; P = 0.018). A small blood distribution area was the only risk factor for decreased FAH [odds ratio (OR) 8.43, confidence interval (CI) 95% (3.04-23.41); P < 0.001]. Binary logistic regression identified PI [OR 2.05, CI 95% (1.36-3.10); P = 0.001], FAH [OR 0.98, CI 95% (0.97-0.99); P = 0.005] and degree of stenosis [OR 0.95, CI 95% (0.92-0.99); P = 0.011] as risk factors for decreased flow after cardiopulmonary bypass (<30 ml/min). An increased PI (>3) was mainly influenced by percentage of flow change [OR 0.99, CI 95% (0.98-1.00); P = 0.031].
FAH and percentage of flow change are related to the dimensions of the target vessel and the degree of stenosis. The addition of flow measurements with the heart arrested provides additional information about the bypass graft, the quality of the anastomosis and the physiology of the coronary circulation.
经时流量测量是评估冠状动脉手术中移植物的一种公认方法。然而，单次流量测量与检测移植物功能障碍的特异性低有关。本研究的目的是评估经时流量测量在不存在原生冠状动脉循环的情况下评估原位内乳动脉移植物的价值，以及靶血管侧支循环血流的相关性。
2014 年至 2018 年，共有 134 例行体外循环冠状动脉旁路移植术的患者接受经时流量测量评估。我们分析了 111 例单根左内乳动脉和 57 例单根右内乳动脉旁路。使用 Spearman ρ系数计算冠状动脉相关参数之间的相关性。计算与心搏骤停（FAH）<30ml/min 和搏动指数（PI）>3.0 相关的降低血流以及流量降低>30%的风险因素。
FAH 与靶血管的直径（Spearman ρ=0.32；P<0.001）、血液分布量（Spearman ρ=0.34；P<0.001）、PI（Spearman ρ=0.19；P=0.019）和狭窄程度（Spearman ρ=-0.17；P=0.042）相关。发现流量变化百分比与 PI（Spearman ρ=-0.47；P<0.0001）、狭窄程度（Spearman ρ=0.42；P<0.001）、靶血管直径（Spearman ρ=-0.22；P=0.008）和血液分布面积（Spearman ρ=-0.19；P=0.018）相关。小的血液分布面积是 FAH 降低的唯一危险因素[比值比（OR）8.43，95%置信区间（CI）（3.04-23.41）；P<0.001]。二元逻辑回归确定了 PI[OR 2.05，95%CI（1.36-3.10）；P=0.001]、FAH[OR 0.98，95%CI（0.97-0.99）；P=0.005]和狭窄程度[OR 0.95，95%CI（0.92-0.99）；P=0.011]是体外循环后流量降低（<30ml/min）的危险因素。PI 升高（>3）主要受流量变化百分比的影响[OR 0.99，95%CI（0.98-1.00）；P=0.031]。
FAH 和流量变化百分比与靶血管的尺寸和狭窄程度有关。在心脏停止的情况下增加流量测量可提供旁路移植物、吻合口质量和冠状动脉循环生理学的额外信息。
