Ye J, Sun J, Shen J, Gregorash L, Summers R, Salerno T A, Deslauriers R
Institute for Biodiagnostics, National Research Council, Winnipeg, Manitoba, Canada.
Circulation. 1997 Nov 4;96(9 Suppl):II-210-5.
The degree of protection provided to the right ventricle during retrograde continuous normothermic blood cardioplegia (RCNBC) remains controversial. The purpose of this study was to determine whether RCNBC is able to provide "adequate" nutritive flow to both ventricles to prevent ischemic metabolism in normal swine hearts. Localized 31P magnetic resonance spectroscopy (MRS) was used to monitor the changes in energy metabolism and intracellular pH (pHi) in each ventricle separately.
Isolated normal swine hearts received 20 minutes of antegrade continuous normothermic blood cardioplegia (ACNBC) for collection of control (baseline) data, followed by 20 minutes of RCNBC. This protocol was repeated four times in five hearts and twice in two hearts. Perfusion pressure was maintained between 70 to 85 and 38 to 43 mm Hg during ACNBC and RCNBC, respectively. pHi, creatine phosphate (PCr), inorganic phosphate (Pi), and ATP were measured continuously in each ventricle during ACNBC and RCNBC, using localized 31P MRS with two surface coils. RCNBC resulted in a significant increase in Pi (LV 222% and RV 244% of the baseline levels, respectively) and a decrease in PCr (left ventricle [LV] to 68% and right ventricle [RV] to 31% of the baseline levels, respectively) in both ventricles relative to ACNBC. The PCr level was significantly lower in the RV than in the LV (31% versus 68%, P<.001) during RCNBC. In one series of experiments (n=5) where ACNBC and RCNBC were alternated every 20 minutes (ACNBC, RCNBC, ACNBC, RCNBC, ACNBC) for a total of 100 minutes, Pi and PCr recovered completely. A continuous and significant decrease in ATP was observed in the RV, and no recovery of ATP was found when switching from RCNBC to ACNBC. No significant decrease in ATP was observed in the LV. pHi remained unchanged in both ventricles during alternate ACNBC and RCNBC.
Energy metabolism in the RV is less well preserved than in the LV during RCNBC. A combination of ACNBC and RCNBC seems to provide good cardiac protection as measured by the recovery of cardiac energetics and pHi.
在逆行持续常温血液心脏停搏（RCNBC）期间对右心室提供的保护程度仍存在争议。本研究的目的是确定RCNBC是否能够为两个心室提供“充足的”营养血流，以防止正常猪心脏出现缺血代谢。使用局部31P磁共振波谱（MRS）分别监测每个心室的能量代谢和细胞内pH值（pHi）变化。
离体正常猪心脏先接受20分钟的顺行持续常温血液心脏停搏（ACNBC）以收集对照（基线）数据，随后接受20分钟的RCNBC。此方案在5颗心脏中重复4次，在2颗心脏中重复2次。在ACNBC和RCNBC期间，灌注压力分别维持在70至85和38至43 mmHg之间。在ACNBC和RCNBC期间，使用带有两个表面线圈的局部31P MRS连续测量每个心室中的pHi、磷酸肌酸（PCr）、无机磷酸（Pi）和三磷酸腺苷（ATP）。与ACNBC相比，RCNBC导致两个心室中的Pi均显著增加（左心室[LV]和右心室[RV]分别为基线水平的222%和244%），PCr均降低（LV降至基线水平的68%，RV降至基线水平的31%）。在RCNBC期间，RV中的PCr水平显著低于LV（31%对68%，P<0.001）。在一系列实验（n = 5）中，ACNBC和RCNBC每20分钟交替一次（ACNBC、RCNBC、ACNBC、RCNBC、ACNBC），共持续100分钟，Pi和PCr完全恢复。在RV中观察到ATP持续且显著下降，从RCNBC切换到ACNBC时未发现ATP恢复。在LV中未观察到ATP显著下降。在交替进行ACNBC和RCNBC期间，两个心室中的pHi保持不变。
在RCNBC期间，RV中的能量代谢不如LV中保存得好。从心脏能量学和pHi的恢复情况来看，ACNBC和RCNBC联合使用似乎能提供良好的心脏保护。
