Rosenfeldt F L, Rabinov M, Little P, Campbell G
J Thorac Cardiovasc Surg. 1986 Sep;92(3 Pt 1):414-24.
The aim of this study was to document the relationship between coronary pressure during reperfusion and myocardial recovery after hypothermic cardioplegia. Isolated canine hearts perfused by a support dog were subjected to 2 hours of cardioplegia at 20 degrees C. Three hearts were reperfused at each of the following pressures: 20, 40, 60, 80, 100, and 150 mm Hg. The reperfusion period lasted 30 minutes, with the pressure being raised gradually from zero to the test level over the first 2 minutes, then being held constant until the end of the period. The results showed that the normal dog heart after 2 hours of hypothermic cardioplegia is tolerant to a wide range of coronary pressures during reperfusion. Hearts reperfused at pressures between 40 and 100 mm Hg had similar values for coronary blood flow, coronary sinus oxygen saturation, myocardial oxygen consumption, lactate flux, contractility, and myocardial adenosine triphosphate content. If coronary reperfusion pressure was 20 mm Hg, [corrected] myocardial rewarming was delayed, myocardial oxygen consumption was decreased, and myocardial ischemia was manifested by marked lactate efflux, high myocardial lactate concentration, and depletion of adenosine triphosphate. If pressure was 150 mm Hg, coronary flow was excessive. To place these results in the context of coronary artery disease, we measured reperfusion pressure in coronary arteries distal to a stenosis in 10 patients studied at the time of coronary bypass grafting. In 13 arteries with major stenoses, distal mean coronary pressure averaged 31 mm Hg while the simultaneously measured mean aortic or radial artery pressure averaged 66 mm Hg. Thus the average gradient across the stenoses was 35 mm Hg (range 15 to 60 mm Hg). We concluded that in normal hearts without ischemic damage, reperfusion can be conducted satisfactorily at mean coronary pressures from 40 to 100 mm Hg. In setting the tolerable limits for reperfusion pressure in patients with severe coronary artery disease, one should make allowance for pressure gradients of up to 60 mm Hg between the aorta and the distal coronary artery.
本研究的目的是记录再灌注期间冠状动脉压力与低温心脏停搏后心肌恢复之间的关系。用辅助犬灌注的离体犬心在20℃下进行2小时的心脏停搏。在以下每个压力水平对三颗心脏进行再灌注：20、40、60、80、100和150mmHg。再灌注期持续30分钟，压力在最初2分钟内从零逐渐升至测试水平，然后保持恒定直至该阶段结束。结果表明，低温心脏停搏2小时后的正常犬心在再灌注期间能耐受较宽范围的冠状动脉压力。在40至100mmHg之间的压力下再灌注的心脏，其冠状动脉血流量、冠状窦血氧饱和度、心肌耗氧量、乳酸通量、收缩性和心肌三磷酸腺苷含量的值相似。如果冠状动脉再灌注压力为20mmHg，[校正后]心肌复温延迟，心肌耗氧量降低，心肌缺血表现为明显的乳酸外流、高心肌乳酸浓度和三磷酸腺苷耗竭。如果压力为150mmHg，冠状动脉血流量过多。为了将这些结果与冠状动脉疾病的情况联系起来，我们在10例冠状动脉搭桥手术时研究的患者中测量了狭窄远端冠状动脉的再灌注压力。在13条有严重狭窄的动脉中，远端平均冠状动脉压力平均为31mmHg，而同时测量的平均主动脉或桡动脉压力平均为66mmHg。因此，跨狭窄的平均梯度为35mmHg（范围为15至60mmHg）。我们得出结论，在没有缺血损伤的正常心脏中，平均冠状动脉压力在40至100mmHg之间时可进行满意的再灌注。在确定严重冠状动脉疾病患者再灌注压力的耐受限度时，应考虑到主动脉与远端冠状动脉之间高达60mmHg的压力梯度。
