Segel L D, Follette D M
Department of Internal Medicine, University of California School of Medicine, Davis 95616.
J Thorac Cardiovasc Surg. 1993 Nov;106(5):811-22.
This study was undertaken to determine whether hearts preserved with intermittent coronary perfusion would recover physiologic function after a prolonged period of hypothermic preservation. Intermittent perfusion is commonly used for cardioplegia, but its efficacy in long-term heart preservation has not yet been demonstrated. Five groups of isolated rat hearts were studied (n = 7 per group): (1) fresh nonpreserved control hearts; (2) hearts preserved with continuous low-pressure perfusion via the aorta; (3) hearts preserved with cycles of 5 minutes of perfusion followed by 25 minutes of nonperfusion; (4) hearts preserved with cycles of 10 minutes of perfusion followed by 25 minutes of nonperfusion; (5) hearts preserved with submersion storage without perfusion. An oxygenated extracellular-type crystalloid medium (oxygen tension = 820 +/- 5 mm Hg) was used as a preservation medium; preservation was for 12 hours. During preservation, the coronary resistance of the intermittent perfusion-preserved hearts increased significantly, and these hearts produced significantly more excess lactate than did hearts in the other two preservation groups. The submersion-stored hearts exhibited no postpreservation ventricular function in an isolated perfused working rat heart system. The poststorage function of the other four groups, which was quantified during a 4-hour, 37 degrees C perfusion period at constant heart rate, indicated that there were no significant group differences with respect to output or energetics (coronary flow, aortic output, cardiac output, myocardial oxygen consumption, and external work efficiency). The intermittent perfusion-preserved hearts had significantly lower postpreservation contractile function (left ventricular systolic pressure, peak rates of left ventricular pressure development and relaxation, peak aortic flow rate, stroke work, and peak power) and higher left ventricular end-diastolic pressure compared with the control group. Although hearts preserved with intermittent perfusion had a loss of contractile function and decreased compliance compared with fresh hearts, after preservation they had better function than did hearts preserved with submersion storage and the same function as hearts preserved with continuous perfusion.
本研究旨在确定经间歇性冠状动脉灌注保存的心脏在长时间低温保存后是否能恢复生理功能。间歇性灌注常用于心脏停搏液，但尚未证明其在长期心脏保存中的有效性。研究了五组离体大鼠心脏（每组n = 7）：（1）新鲜未保存的对照心脏；（2）经主动脉连续低压灌注保存的心脏；（3）以5分钟灌注和25分钟非灌注循环保存的心脏；（4）以10分钟灌注和25分钟非灌注循环保存的心脏；（5）经浸没储存且无灌注保存的心脏。使用含氧的细胞外液型晶体培养基（氧分压 = 820±5 mmHg）作为保存培养基；保存12小时。在保存期间，间歇性灌注保存的心脏的冠状动脉阻力显著增加，且这些心脏产生的过量乳酸比其他两个保存组的心脏显著更多。在离体灌注工作大鼠心脏系统中，浸没储存的心脏未表现出保存后的心室功能。其他四组的保存后功能在37℃、心率恒定的4小时灌注期进行量化，结果表明在输出或能量学（冠状动脉流量、主动脉输出、心输出量、心肌氧消耗和外部工作效率）方面无显著组间差异。与对照组相比，间歇性灌注保存的心脏保存后的收缩功能显著降低（左心室收缩压、左心室压力上升和舒张的峰值速率、主动脉峰值流速、搏功和峰值功率），左心室舒张末期压力更高。尽管与新鲜心脏相比，经间歇性灌注保存的心脏收缩功能丧失且顺应性降低，但保存后它们的功能优于经浸没储存保存的心脏，且与经连续灌注保存的心脏功能相同。
