不同心肌保护方法对双瓣膜置换术心肌氧摄取率的影响

目的了解不同心肌保护方式对二尖瓣和主动脉瓣双瓣膜置换手术心肌氧摄取率的影响.方法 24例患者随机分为3组,每组8例.①顺行灌注组:先经主动脉根部间断灌注冷血心脏麻痹液,完成二尖瓣置换,再斜行切开主动脉,直接经左、右冠状动脉开口灌注心脏麻痹液,完成主动脉瓣置换术. ②逆行灌注组:经冠状静脉窦间断逆行灌注冷血心脏麻痹液,依次完成二尖瓣置换和主动脉瓣置换术. ③顺灌加逆灌注组:先按顺行灌注方法完成二尖瓣置换,再采用逆灌方法完成主动脉瓣置换术.观察3组患者心肌氧摄取率、乳酸的变化.结果 24例患者无手术死亡,均痊愈出院.阻断主动脉期间心肌氧摄取率均降低,3组间无显著性差异;开放主动脉后10 min心肌氧摄取率仍低于阻断主动脉前,逆行灌注组降低更明显.阻断主动脉和开放主动脉10 min 3组各时相点动脉血和冠脉回流血乳酸含量均较阻断主动脉前明显升高,而冠脉回流血乳酸含量又较动脉血含量高.逆灌组阻断主动脉80 min和开放主动脉10 min动脉血和冠脉回流血液乳酸浓度均高于顺灌组,开放主动脉10 min时则高于顺灌加逆灌组.结论双瓣膜置换手术中顺行灌注或顺灌加逆灌注冷血心脏麻痹液的心肌保护效果较好.

Effects of various myocardial protections on the rate of myocardial oxygen uptake in patients undergoing mitral and aortic valve replacement

Objective To evaluate the effects of various myocardial protections on the rate of myocardial oxygen uptake in patients undergoing mitral and aortic valve replacement (double valve replacement, DVR). Methods A total of 24 patients subjected to DVR were assigned to 3 groups randomly. In the intermittent antegrade cardioplegia group (AC group, n=8), the heart was arrested during undergoing DVR by cold blood cardioplegia perfusion via coronary ostium; in the intermittent retrograde cardioplegia group (RC group, n=8), via coronary sinus; in the intermittent antegrade combined with retrograde cardioplegia group (ACRC group, n=8), the heart was arrested during undergoing mitral valve replacement by cold blood cardioplegia perfusion via coronary ostium, and undergoing aortic valve replacement via coronary sinus. The rate of myocardial oxygen uptake, the levels of lactate in arterial blood and blood returned from coronary artery ostia or coronary sinus were measured. Results No early operative death occurred and all 24 patients were cured. The rate of myocardial oxygen uptake during aortic cross-clamping was markedly decreased than that before aortic cross-clamping in the three groups, but no statistical difference was observed between the three groups (P>0.05). The rate of myocardial oxygen uptake at 10 min after aortic cross-clamp removing was decreased than that before aortic cross-clamping in the three groups, and it was lower in RC group than that in the other two groups. Lactate concentration in arterial blood and blood returned from coronary artery ostia or coronary sinus was elevated notably during aortic cross-clamping and at 10 min after aortic cross-clamp removing as compared with that before aortic cross-clamping in three groups, lower at 80 min after aortic cross-clamping and at 10 min after aortic cross-clamp removing in RC group than that in AC group, and lower at 10 min after aortic cross-clamping removing in RC group than that in ACRC group. Conclusion Either intermittent antegrade cardioplegia or intermittent antegrade combined with retrograde cardioplegia during undergoing DVR leads to better outcome.