Cremer J, Harringer W, Hermann G, Lins M, Brandt M, Ostermann C, Haverich A
Division of Thoracic and Cardiovascular Surgery, Hannover Medical School, Germany.
Eur J Cardiothorac Surg. 1996;10(11):958-63; discussion 964. doi: 10.1016/s1010-7940(96)80397-6.
The low perioperative flow rates of internal thoracic artery (ITA) conduits have been regarded as a limitation of their use in critical coronary situations with a high myocardial blood demand. To clarify whether these restrictions are justified, early postoperative flow rates were determined.
Following bilateral ITA grafting, 48 of 106 patients (April 1993-September 1994) underwent recatheterization. Subsequent to control angiography between days 8 and 12, 20 of these patients were studied by intravascular Doppler techniques applied for ITA grafts supplying the left anterior descending artery (LAD) and branches of the circumflex system (CX) (n = 20). Doppler spectral analysis allowed for determination of the average peak velocity and diastolic-systolic velocity ratio. Vascular diameters were assessed by simultaneously performed quantitative angiography and mean flow rates were calculated. All parameters were recorded at rest and following selective stimulation with nitroglycerin (0.2 mg) and papaverine (12.5 mg) to evaluate the graft flow capacity.
Baseline values of average peak velocity at rest were 24.6 +/- 11.5 cm/s for ITA-LAD conduits and 21.9 +/- 6.8 cm/s for ITA-CX pedicles. Following dilative stimulation with papaverine, a significant increase in average peak velocities were obtained for both locations (ITA-LAD: 47.3 +/- 17.1 cm/s, ITA-CX: 42.3 +/- 11.8 cm/s). The application of nitroglycerin had a similar effect (ITA-LAD: 42.6 +/- 15.3 cm/s, ITA-CX: 40.3 +/- 10.7 cm/s). The vascular diameters of ITA conduits remained unchanged on nitroglycerin stimulation, whereas papaverine effected significant dilatation in both locations. Flow rates at rest were not significantly different (ITA-LAD: 51.0 +/- 34.2 ml/min, ITA-CX: 44.7 +/- 16.4 ml/min) and maximal flow increase was observed following papaverine stimulation of the LAD conduits (116.1 +/- 90.6 ml/min). Dilative stimulation effected an increase in diastolic-systolic velocity ratios from average values at rest in a range between 34% and 41.7% for both groups and substances.
The basic blood flow in functioning ITA grafts appears to be similar in conduits supplying the LAD and marginal branches. Flow rates between 50 and 60 ml/min at rest should meet myocardial demands, even in the LAD position. Increased flow rates were predominantly based on higher flow velocities with an increased diastolic flow proportion. Enlargement of the graft diameter may exert additional effects, at least following papaverine stimulation at a particular concentration.
胸廓内动脉（ITA）导管围手术期低血流率被认为是其在心肌血需求高的严重冠状动脉情况中应用的一个限制因素。为了阐明这些限制是否合理，测定了术后早期的血流率。
在106例患者（1993年4月至1994年9月）行双侧ITA移植术后，其中48例接受了再次导管检查。在第8至12天进行对照血管造影后，对其中20例患者应用血管内多普勒技术研究供应左前降支（LAD）和回旋支系统（CX）分支的ITA移植物（n = 20）。多普勒频谱分析可测定平均峰值速度和舒张期与收缩期速度比值。通过同时进行的定量血管造影评估血管直径，并计算平均血流率。所有参数在静息状态下以及用硝酸甘油（0.2 mg）和罂粟碱（12.5 mg）进行选择性刺激后记录，以评估移植物的血流能力。
静息状态下，ITA - LAD导管平均峰值速度的基线值为24.6±11.5 cm/s，ITA - CX蒂为21.9±6.8 cm/s。在用罂粟碱进行扩张刺激后，两个部位的平均峰值速度均显著增加（ITA - LAD：47.3±17.1 cm/s，ITA - CX：42.3±11.8 cm/s）。应用硝酸甘油有类似效果（ITA - LAD：42.6±15.3 cm/s，ITA - CX：40.3±10.7 cm/s）。硝酸甘油刺激后ITA导管的血管直径保持不变，而罂粟碱在两个部位均引起显著扩张。静息状态下的血流率无显著差异（ITA - LAD：51.0±34.2 ml/min，ITA - CX：44.7±16.4 ml/min），LAD导管经罂粟碱刺激后观察到最大血流增加（116.1±90.6 ml/min）。扩张刺激使两组和两种物质的舒张期与收缩期速度比值从静息平均值增加了34%至41.7%。
在供应LAD和边缘分支的导管中，功能正常的ITA移植物的基础血流似乎相似。即使在LAD位置，静息状态下50至60 ml/min的血流率应能满足心肌需求。血流率增加主要基于更高的流速以及舒张期血流比例增加。移植物直径增大可能会产生额外影响，至少在特定浓度的罂粟碱刺激后如此。
