Splanchnic oxygen transport after cardiac surgery: evidence for inadequate tissue perfusion after stabilization of hemodynamics

Objective To evaluate the adequacy of visceral oxygen transport and gastric pH_i after open heart surgery in patients with stable hemodynamics.Design Nonrandomized control trial.Setting A general intensive care unit in a tertiary care center.Patients Sixteen postoperative cardiac surgery patients were studied after stabilization of systemic hemodynamics.Interventions The effect of dobutamine infusion (6 g kg^–1 min^–1) on systemic and regional oxygen transport was studied in ten patients, with six patients serving as controls. Systemic oxygen consumption was measured by indirect calorimetry and splanchnic and femoral blood flow, by continuous infusion of indocyanine green using regional catheters and gastric mucosal pH_i by gastric tonometer.Measurements and results Gastric mucosal acidosis was observed in half of the patients. Dobutamine increased cardiac output (3.2±0.6 vs 4.4±0.7l· min^–1·m^–2;P<0.05), splanchnic blood flow (0.68±0.28 vs 0.91±0.281· min^–1·m^–2;p<0.05) and femoral blood flow (0.25±0.08 vs 0.32±0.11l·min^–1·m^–2;p<0.05). Changes in splanchnic oxygen delivery and consumption were parallel in the two study groups. In response to dobutamine, gastric pH_i did not change (7.30±0.08 vs 7.31±0.06; NS), while in the control group, gastric pH_i tended to decrease (7.32±0.04 vs 7.28±0.06; NS). Systemic oxygen consumption increased in response to dobutamine (141±11 vs 149±11 ml· min^–1·m^–2;P<0.05) but did not change in the control group.Conclusions We conclude that a mismatch between splanchnic oxygen delivery and demand may be present despite stabilization of systemic hemodynamics after cardiac surgery. This is suggested by the parallel changes in splanchnic oxygen delivery and consumption. Dobutamine is likely to improve splanchnic tissue perfusion at this phase.This study was supported in part by the senior researcher's grant no. 1945/3015/92 to Dr. Takala from the Academy of Finland     

多巴酚丁胺负荷超声心动图评价冠状动脉介入治疗后再狭窄

目的　探讨多巴酚丁胺负荷超声心动图 (DSE)评价经皮冠状动脉介入治疗 (PCI)后再狭窄的准确性和可行性。方法　 47例PCI后 6～ 18个月的患者在冠状动脉造影前 1周内接受标准方案DSE检查 ,多巴酚丁胺剂量递增方案为 5、10、2 0、3 0 μg·kg-1·min-1,直至最大剂量 40 μg·kg-1·min-1,每阶段持续滴注至少 3min。比较DSE和冠状动脉造影检查结果的一致性。DSE阳性的标准是原有的室壁节段运动异常加重或出现新的室壁节段运动异常或发生明显心绞痛。结果　DSE评价PCI后再狭窄的敏感性为 64 % ,特异性为 86% ,准确率为 72 %。结论　DSE可用于非侵入性评价PCI后再狭窄 ,且费用经济、安全可行     

多巴酚丁胺负荷超声和实时声学造影评价介入治疗术后心肌灌注

目的应用实时心肌声学造影和多巴酚丁胺负荷超声心动图,定量评价冠状动脉(冠脉)介入治疗术后心肌血流量和血流储备。方法12例前壁和前间隔心肌梗死患者,在心肌梗死后3周至1年择期行冠脉造影和支架介入术,在介入术后1周,在基础状态下和多巴酚丁胺负荷试验时进行实时声学造影。应用Qlab软件定量分析实时声学造影再灌注曲线,得到曲线平台值(A)、曲线上升速度(β)和A·β(心肌血流量,MBF),以及各参数的储备值。结果负荷试验时的室壁运动指数明显下降(1.45±0.24对1.25±0.18,P<0.05),左室射血分数显著增加[(45.74±8.45)%对(59.80±11.92)%,P<0.05]。静息状态和负荷时,正常冠脉供血节段的A、β和MBF均显著高于病变冠脉供血区(均P<0.05)。与静息时相比,负荷时正常冠脉供血节段的A、β和MBF显著增加(均P<0.001),病变冠脉供血区的A、β和MBF也明显上升(均P<0.01),但增加幅度不及正常冠脉供血区(P<0.05)。除A值储备外(P=0.17),病变冠脉供血区的β和MBF的储备均明显低于正常冠脉供血区(P分别为1.06×10-7,7.66×10-5)。存活心肌节段β及MBF储备明显高于梗死心肌节段(均P<0.05)。结论心肌梗死患者在择期介入治疗术后仍存在心肌灌注异常和室壁运动障碍,多巴酚丁胺负荷实时声学造影能够有效地定量心肌血流量和检测存活心肌,有助于判断心肌的血流储备能力,为临床评价冠心病提供了简便、可靠、无创伤性的新方法。     

Comparison of two-dimensional speckle and tissue Doppler strain measurement during dobutamine stress echocardiography: an angiographic correlation.

AIMS: Two-dimensional (2D)-strain derived from speckle-tracking is an alternative to tissue velocity imaging (TVI)-based strain. We compared their feasibility and accuracy in 150 patients undergoing dobutamine stress echocardiography (DSE) and coronary angiography. METHODS AND RESULTS: 2D- and TVI-strain were obtained in three apical views at rest and peak stress. Peak systolic strain rate (SR), endsystolic strain (epsilon(end-sys)), and peak strain (epsilon(peak)) were measured off-line at rest and peak stress, and results were compared with wall motion analysis and significant coronary artery disease (CAD > or = 70% diameter stenosis). Optimal cut-offs were derived from receiver operating characteristic (ROC) curves for sentinel segments. The most feasible method was 2D-strain at rest, and TVI-strain at peak stress. The average peak SR and epsilon(end-sys) at peak stress in segments of patients with significant CAD was less than in segments of patients without CAD (P < 0.0001) and mean PSI at peak stress was higher (P < 0.0001) with both 2D- and TVI-strain. Peak systolic SR at peak stress had the best area under the ROC for both 2D- (AUC 0.67) and TVI-strain (AUC 0.71) for the diagnosis of CAD. The accuracy of WMS (75%) for diagnosis of CAD per patient was similar to 2D-SR (69%) and TVI-SR (74%). The accuracy of 2D-SR and TVI-SR at peak stress was 78 vs. 79% (P = NS) for LAD, 67 vs. 73% (P = NS) for LCX, and 59 vs. 74% (P = 0.008) for RCA disease. CONCLUSION: Measurement of speckle tracking strain during DSE is feasible and similar in accuracy to TVI-strain in the anterior, but not in the posterior circulation.     

Attenuation of cardiac remodelling by endocardial injection of erythropoietin: ultrasonic strain-rate imaging in a model of hibernating myocardium.

AIMS: The aim of this study was to investigate whether erythropoietin (EPO) has cardioprotective effects in a chronic myocardial ischaemia model regarding strain-rate imaging parameters during dobutamine stress echocardiography (DSE). METHODS AND RESULTS: An ameroid constrictor was placed around the circumflex artery in 13 pigs to induce hibernating myocardium by a chronic vessel occlusion. The pigs were randomized 14 days later: seven pigs receiving 10,000 U EPO and six pigs receiving placebo injected into the ischaemic region using a NOGAtrade mark-guided transendocardial catheter. At weeks 2 and 6, animals were examined by DSE, electromechanical mapping, and coronary angiography. During incremental dobutamine infusion, regional radial function was monitored by measuring peak systolic strain-rates (SRsys), systolic strains (epsilonsys), and post-systolic strains (epsilonps). At week 6, the animals were pathohistologically investigated. Echocardiography revealed 2.2+/-0.8 hypokinetic segments in the EPO-treated animals in comparison with 3.3+/-0.9 akinetic segments per animal in the controls. The mean ejection fraction was reduced in the control group (55+/-3 vs. 66+/-4%, P=0.057). Strain-rate imaging revealed ischaemic myocardium in EPO-treated animals and non-viable myocardium in the controls (P=0.0001). Histological analysis of the ischaemic region revealed a reduction of myocardial fibrosis (8+/-1 vs. 27+/-5%) in the EPO-treated group. The transmural extension of fibrosis and the echocardiographic deformation data correlated in the posterior walls (EPO group): epsilonsys at rest r=0.83; peak SRsys during dobutamine stimulation r=0.92, P=0.01. CONCLUSION: Endocardial EPO injection may induce cardioprotective effects in chronic ischaemic myocardium and helps to obtain the myocardial contractile reserve, objectified by ultrasonic strain-rate imaging.     

Non-invasive diagnosis of coronary artery disease by quantitative stress echocardiography: optimal diagnostic models using off-line tissue Doppler in the MYDISE study.

AIMS: To develop optimal methods for the objective non-invasive diagnosis of coronary artery disease, using myocardial Doppler velocities during dobutamine stress echocardiography. METHODS AND RESULTS: We acquired tissue Doppler digital data during dobutamine stress in 289 subjects, and measured myocardial responses by off-line analysis of 11 left ventricular segments. Diagnostic criteria developed by comparing 92 normal subjects with 48 patients with coronary disease were refined in a prospective series of 149 patients referred with chest pain. Optimal diagnostic accuracy was achieved by logistic regression models, using systolic velocities at maximal stress in 7 myocardial segments, adjusting for independent correlations directly with heart rate and inversely with age and female gender (all p<0.001). Best cut-points from receiver-operator curves diagnosed left anterior descending, circumflex and right coronary disease with sensitivities and specificities of 80% and 80%, 91% and 80%, and 93% and 82%, respectively. All models performed better than velocity cut-offs alone (p<0.001). CONCLUSION: Non-invasive diagnosis of coronary artery disease by quantitative stress echocardiography is best performed using diagnostic models based on segmental velocities at peak stress and adjusting for heart rate, and gender or age.     

多巴酚丁胺￣（99m）锝－MIBI心肌断层显像对冠心病的诊断价值

以冠状动脉造影为标准，在３９例患者评价了多巴酚丁胺￣９９ｍ锝－ＭＩＢｌ心肌断层显像对冠心病的诊断价值。结果显示其诊断冠心病的敏感性和特异性分别为９２．９％和９０．９％；诊断冠状动脉单支、双支、三支病变的敏感性分别为９０．９％、８７．５％和１００％。１７例多支病变中１５例（敏感性８８．２％）被检出有多支血管供血区域心肌受累。研究中无严重副反应。结论：多巴酚丁胺￣９９ｍ锝－ＭＩＢＩ心肌断层显像作为冠心病无创诊断方法是安全可行的。     

CK技术评价急性心肌梗死患者存活心肌和住院并发症的关系

为探讨存活心肌与急性心肌梗死（AMI）后住院并发症的关系，应用彩色室壁运动分析技术（CK）结合多巴酚丁胺负荷超声心动图试验（DSE）检测24例AMI患者。结果：23例成功地进行了CK－DSE，CK示299个心肌节段中有205个室壁运动正常，74个室壁运动消失，DSE后8例观察到22个运动消失的节段彩色编码标记的运动轨迹增加一级，列为存活心肌组，15例试验后运动消失的节段CK彩色编码无变化，列为无存活心肌组。前组仅3例在住院过程中出现并发症，后组10例出现并发症。后组住院并发症发生率明显高于前组（P＜0．05），而反映心肌梗死面积的CPK峰值在两组中无明显差异（P＞0．05）。表明AMI后存活心肌与住院并发症有一定关系。     

急性心肌梗塞后应用多巴酚丁胺负荷超声心动图对心肌存活性的研究

本文目的应用多巴酚丁胺负荷超声心动图研究急性心肌梗塞后梗塞区域心肌存活性。选择36例急性心肌梗塞患者，用5μg／kg·min多巴酚丁胺静脉滴注，体表超声心动图于用药前后对比观察梗塞区域心肌室壁运动和收缩期增厚率（T％），识别心肌存活性。36例患者分为576段心肌，基础状态下94段心肌运动消失，T％为0。静注5μg/kg·min多巴酚丁胺后，94段心肌中30段心肌恢复或部分恢复运动，T％增加121～60．0％。结果提示94段运动消失的心肌中30段（31．9％）具有存活性。表明多巴酚丁胺负荷超声心动图对急性心肌梗塞后存活心肌的识别是安全、可靠的，具有十分重要的临床意义。     

小剂量多巴胺联合多巴酚丁胺辅助治疗对重症肺炎患儿血清学指标的影响及其与预后的关系

目的:分析小剂量多巴胺联合多巴酚丁胺辅助治疗对重症肺炎患儿炎症因子水平的影响及其与预后情况的相关性.方法:选择在本院接受住院治疗的86例重症肺炎患儿作为研究对象,随机分为接受常规治疗的对照组及接受小剂量多巴胺联合多巴酚丁胺辅助治疗的观察组,比较两组患儿的血清学指标、临床症状改善时间.结果:(1)炎症因子:观察组患儿的白介素-8(IL-8)、C反应蛋白(CRP)及肿瘤坏死因子-α(TNF-α)含量低于对照组(P＜0.05);(2)免疫分子:观察组患儿外周血中TLR4、核转录因子(NF-κB)和MyD88含量低于对照组(P＜0.05);(3)基质金属蛋白酶(MMP)功能:观察组患儿的MMP9含量以及MMP9/金属蛋白酶组织抑制剂1(TIMP1)比例低于对照组,TIMP1含量高于对照组(P＜0.05);(4)IL-8、CRP、TNF-α、TLR4、NF-κB、MyD88、MMP9、TIMP1含量以及MMP9/ TIMP1比例与临床症状改善时间呈正相关,TIMP1含量与临床症状改善时间呈负相关.结论:小剂量多巴胺联合多巴酚丁胺辅助治疗有助于降低血清炎症因子、免疫分子含量,降低MMP分子的损伤作用,且与临床症状改善情况密切相关.