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预测AMI患者转归低能量连续MCE效果好
微血管的再灌注是确保AMI后心肌存活的先决条件。为充分评价心肌的灌注情况，对心肌的血流速度和容积等参数均需要进行评估。采用低能量连续MCE技术能够快速评价心肌灌注的参数。Janardhanan等研究低能量连续MCE技术是否能准确识别MI患者接受再灌注治疗后的坏死心肌。
50例患者在MI后的7～10天接受低能量连续MCE检查（经静脉注射显影剂Optison）。检测患者心肌灌注和室壁厚度的起始值，12周后，重新评价患者的节段和整体左室功能。
在297个功能不全的节段中，15个心动周期内的MCE检查结果显示，无对照增强的节段为172个，其中160个（93%）节段无改善。在15个心动周期中，77个节段的MCE检查显示有对比度，其中65个（84%）节段功能恢复。研究发现，患者MCE检查中对比范围和强度越大，3个月内的左室功能就越好（P<0.001，相关系数为-0.91）。几乎所有功能不全的心肌灌注<20%的患者（94%）左室功能均无改善。MCE检查结果和肌酐激酶峰值是患者功能恢复的独立预测因子（P<0.001）。
研究者认为，低能量连续MCE技术是一种准确、快速诊断MI后微血管灌注的床旁技术，可有效地预测MI后心肌功能不全患者的晚期功能恢复。
Am J Cardiol. 2003 Sep 1;92(5):493-7.
Usefulness of myocardial contrast echocardiography using low-power continuous imaging early after acute myocardial infarction to predict late functional left ventricular recovery.
Janardhanan R, Swinburn JM, Greaves K, Senior R.
Department of Cardiovascular Medicine, Northwick Park Hospital, Harrow, United Kingdom.
Microvascular perfusion is a prerequisite for ensuring viability early after acute myocardial infarction (AMI). For adequate assessment of myocardial perfusion, both myocardial blood volume and velocity need to be evaluated. Due to its high frame rate, low-power continuous myocardial contrast echocardiography (MCE) can rapidly assess these parameters of myocardial perfusion. We hypothesized that the technique can accurately differentiate necrotic from viable myocardium after reperfusion therapy in AMI. Accordingly, 50 patients underwent low-power continuous MCE using intravenous Optison (Amersham Health, Amersham, Middlesex, United Kingdom) 7 to 10 days after AMI. Myocardial perfusion (contrast opacification assessed over 15 cardiac cycles after the destruction of microbubbles with high energy pulses) and wall thickening were assessed at baseline. Regional and global left ventricular (LV) function was reassessed after 12 weeks. Out of the 297 dysfunctional segments, MCE detected no contrast enhancement during 15 cardiac cycles in 172 segments, of which 160 (93%) failed to show improvement. MCE demonstrated contrast opacification during 15 cardiac cycles in 77 segments, of which 65 (84%) showed recovery of function. The greater the extent and intensity of contrast opacification, the better the LV function at 3 months (p <0.001, r = -0.91). Almost all patients (94%) with <20% perfusion in dysfunctional myocardium (assessing various cut-offs) failed to demonstrate an improvement in LV function. MCE and peak creatine kinase proved to be independent predictors of functional recovery (p <0.001). In conclusion, low-power continuous MCE is an accurate and rapid bedside technique to identify microvascular perfusion after AMI. This technique may be utilized to reliably predict late recovery of function in dysfunctional myocardium after AMI.
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作者:admin@医学,生命科学 2011-07-14 00:43
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