Montgomery W D, Vitolla G, Ali A, Pagni S, Ballen J L, Santamore W P, Calafiore A M, Spence P A
University of Louisville, Division of Cardiovascular and Thoracic Surgery, Kentucky, USA.
Eur J Cardiothorac Surg. 1997 Sep;12(3):436-42. doi: 10.1016/s1010-7940(97)00162-0.
Surgeons have traditionally relied on ring preparations to predict how arterial bypass conduits will behave in the postoperative circulation.
This study compared pharmacologic [norepinephrine (NE) challenge] and physiologic [arterial preload] responses of gastroepiploic (GEA) and internal thoracic (ITA) arteries in a standard static ring preparation and a dynamic perfusion system.
Six GEAs (1.0-1.5 mm dia.) and six ITAs (1.5-2.0 mm dia.) 11 cm long were harvested from adult pigs and mounted on a computer controlled perfusion system. Inflow pressure was set at 80 mmHg and outflow resistance was adjusted to simulate high (80-90 ml/min) and low (15-20 ml/min) flow demands. NE response (10(-9)-10(-5) M) was measured under low flow conditions and at high flow conditions when distal arterial pressure (load) was reduced. NE response (10(-9)-10(-5) M) was also evaluated in arterial rings (ITA N = 6, GEA N = 6) with tensions adjusted to simulate the loads occurring at low flow (80 mmHg) and high flow (60 mmHg) situations.
In the static ring preparation, NE response [ED50] was similar for both GEA and ITA and was not affected by load. The dynamic preparation demonstrated that the GEAs were significantly more responsive to NE than the ITAs [ED50 high flow ITA 6.1 +/- 0.3**, GEA 7.2 +/- 0.3***; *P < 0.05 versus baseline, **P < 0.05 versus low flow values, ***P < 0.05 versus ITA]. Furthermore, in the dynamic preparation, NE response was profoundly affected by reduced load which occurs under high flow conditions [7.18 +/- 0.3 versus 6.1 +/- 0.3 under high flow and 5.8 +/- 0.1 versus no response under low flow conditions].
Static ring preparations do not discern differences between ITA and GEA susceptibility to spasm and fail to detect the effect of load. The dynamic preparation demonstrated significant differences between the GEA and ITA potential to spasm which is consistent with widespread clinical experience. Furthermore a dynamic preparation is highly sensitive to reduced load which occurs under high flow conditions. Although it is more demanding, the dynamic preparation provides superior information to the surgeon in predicting the behavior of arterial bypass grafts.
传统上，外科医生依靠血管环制备来预测动脉旁路移植物在术后循环中的表现。
本研究比较了在标准静态血管环制备和动态灌注系统中，胃网膜动脉（GEA）和胸廓内动脉（ITA）的药理学[去甲肾上腺素（NE）激发试验]和生理学[动脉前负荷]反应。
从成年猪身上获取6条直径为1.0 - 1.5毫米、长11厘米的GEA和6条直径为1.5 - 2.0毫米、长11厘米的ITA，并将其安装在计算机控制的灌注系统上。将流入压力设定为80 mmHg，并调整流出阻力以模拟高流量（80 - 90毫升/分钟）和低流量（15 - 20毫升/分钟）需求。在低流量条件下以及在高流量条件下降低远端动脉压力（负荷）时测量NE反应（10⁻⁹ - 10⁻⁵ M）。还在血管环（ITA n = 6，GEA n = 6）中评估NE反应（10⁻⁹ - 10⁻⁵ M），将张力调整为模拟低流量（80 mmHg）和高流量（6 mmHg）情况下出现的负荷。
在静态血管环制备中，GEA和ITA的NE反应[半数有效剂量（ED50）]相似，且不受负荷影响。动态制备表明，GEA对NE的反应明显比ITA更敏感[高流量时ITA的ED50为6.1 ± 0.3**，GEA为7.2 ± 0.3***；*与基线相比P < 0.05，**与低流量值相比P < 0.05，***与ITA相比P < 0.05]。此外，在动态制备中，NE反应受到高流量条件下负荷降低的深刻影响[高流量时为7.18 ± 0.3，低流量条件下无反应时为5.8 ± 0.1]。
静态血管环制备无法区分ITA和GEA对痉挛的易感性差异，也无法检测负荷的影响。动态制备显示出GEA和ITA在痉挛可能性方面的显著差异，这与广泛的临床经验一致。此外，动态制备对高流量条件下负荷降低高度敏感。尽管要求更高，但动态制备为外科医生预测动脉旁路移植物的行为提供了更优质的信息。
Zotero 插件