Jin X Y, Gibson D G, Pepper J R
Department of Cardiothoracic Surgery, Royal Brompton Hospital, London, England.
Ann Thorac Surg. 1999 Mar;67(3):705-10. doi: 10.1016/s0003-4975(99)00076-4.
The interrelations between myocardial stroke work and coronary flow velocity have not been fully defined during aortic valve replacement or with different cardioplegias.
Twenty-six patients (15 men age 63+/-13 years) who had elective isolated aortic valve replacement were studied by transesophageal Doppler echocardiography with simultaneous high fidelity left ventricular pressure. Fifteen patients received cold blood cardioplegia and 11 had warm blood cardioplegia. Myocardial stroke work and flow velocities in proximal left anterior descending coronary artery were quantified simultaneously before cardiopulmonary bypass and at 1, 6, 12, and 20 hours afterwards.
Myocardial stroke work decreased postoperatively in both groups (160+/-19 versus 228+/-19 mJ/cm3 per minute, with cold blood cardioplegia; 135+/-22 versus 227+/-22 mJ/cm3 per minute with warm blood cardioplegia; both p<0.001 versus time, but p>0.05 versus cardioplegia, by two-way analysis of variance). Left anterior descending artery flow velocity-time integral per minute increased significantly in both groups (26.1+/-2.1 versus 15.0+/-2.1 m/min with cold blood cardioplegia; 32.8+/-2.5 versus 14.4+/-2.5 m/min with warm blood cardioplegia; both p<0.001 versus time, but p>0.05 versus cardioplegia). Thus, at 1 hour postoperatively the mJ x cm(-3) x m(-1) x min ratio of myocardial stroke work to left anterior descending artery flow velocity-time integral decreased significantly in both groups (4.3+/-1.6 versus 16.3+/-1.7 mJ x cm(-3) x m(-1) x min with warm blood cardioplegia, and 7.4+/-1.4 versus 17.9+/-1.4 J x cm(-3) x m(-1) x min with cold blood cardioplegia; both p<0.001 versus time). Warm blood cardioplegia was also associated with a lower mean ratio perioperatively than that with cold blood cardioplegia (7.8+/-0.9 versus 10.9+/-0.7 mJ x cm(-3) x m(-1) x min, p = 0.014).
Coronary hyperemia occurs for at least 20 hours postoperatively when myocardial stoke work has decreased. The ratio of myocardial stroke work to coronary flow velocity appears to be more sensitive than either alone in differentiating the effect of warm versus cold blood cardioplegia.
在主动脉瓣置换期间或使用不同的心脏停搏液时，心肌每搏功与冠状动脉血流速度之间的相互关系尚未完全明确。
对26例（15例男性，年龄63±13岁）择期行单纯主动脉瓣置换术的患者，采用经食管多普勒超声心动图同时记录高保真左心室压力进行研究。15例患者接受冷血心脏停搏液，11例接受温血心脏停搏液。在体外循环前、体外循环后1小时、6小时、12小时和20小时，同时对左前降支冠状动脉近端的心肌每搏功和血流速度进行量化。
两组患者术后心肌每搏功均下降（冷血心脏停搏液组：每分钟160±19 vs 228±19 mJ/cm³；温血心脏停搏液组：每分钟135±22 vs 227±22 mJ/cm³；方差分析显示，两组与时间比较p均<0.001，但与心脏停搏液比较p>0.05）。两组患者左前降支动脉每分钟血流速度时间积分均显著增加（冷血心脏停搏液组：26.1±2.1 vs 15.0±2.1 m/min；温血心脏停搏液组：32.8±2.5 vs 14.4±2.5 m/min；两组与时间比较p均<0.001，但与心脏停搏液比较p>0.05）。因此，术后1小时，两组心肌每搏功与左前降支动脉血流速度时间积分的mJ×cm⁻³×m⁻¹×min比值均显著下降（温血心脏停搏液组：4.3±1.6 vs 16.3±1.7 mJ×cm⁻³×m⁻¹×min；冷血心脏停搏液组：7.4±1.4 vs 17.9±1.4 J×cm⁻³×m⁻¹×min；两组与时间比较p均<0.001）。温血心脏停搏液组围手术期平均比值也低于冷血心脏停搏液组（7.8±0.9 vs 10.9±0.7 mJ×cm⁻³×m⁻¹×min，p = 0.014）。
术后至少20小时心肌每搏功下降时会出现冠状动脉充血。心肌每搏功与冠状动脉血流速度的比值在区分温血与冷血心脏停搏液的效果方面似乎比单独的任何一项更敏感。
