低剂量多巴酚丁胺心脏磁共振评估慢性功能障碍性心肌非透壁梗死节段的收缩储备功能。

Contractile reserve in segments with nontransmural infarction in chronic dysfunctional myocardium using low-dose dobutamine CMR.

机构信息

Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands.

出版信息

JACC Cardiovasc Imaging. 2010 Jun;3(6):614-22. doi: 10.1016/j.jcmg.2010.03.007.

DOI:10.1016/j.jcmg.2010.03.007

PMID:20541717

Abstract

OBJECTIVES

This study sought to quantify contractile reserve of chronic dysfunctional myocardium, in particular in segments with intermediate transmural extent of infarction (TEI), using low-dose dobutamine cardiac magnetic resonance (CMR) in patients with a chronic total coronary occlusion (CTO).

BACKGROUND

Recovery of dysfunctional segments with intermediate TEI after percutaneous coronary intervention is variable and difficult to predict, and may be related to contractility of the unenhanced rim.

METHODS

Fifty-one patients (mean age 60 +/- 9 years, 76% male) with a CTO underwent CMR at baseline and 35 patients underwent CMR at follow-up to quantify segmental wall thickening (SWT) at rest during 5 and 10 microg/kg/min dobutamine, and at follow-up. Delayed-enhancement CMR was performed to quantify TEI. Dysfunctional segments were stratified according to TEI, end-diastolic wall thickness (EDWT), or unenhanced rim thickness, and SWT was quantified. Segments with an intermediate TEI (25% to 75%) were further stratified according to baseline SWT of the unenhanced rim (SWT(UR)) (<45% and >45%), and SWT was quantified. For each parameter, odds ratio (OR) and diagnostic performance for the prediction of contractile reserve were calculated.

RESULTS

Significant contractile reserve was present in dysfunctional segments with EDWT >6 mm, unenhanced rim thickness >3 mm, or TEI of <25%; only TEI had significant relation with contractile reserve (OR: 0.98; 95% confidence interval [CI]: 0.96 to 0.99; p = 0.02). In segments with intermediate TEI (n = 58), mean SWT did not improve significantly. However, segments with SWT(UR) <45% showed contractile reserve and improved at follow-up, whereas segments with SWT(UR) >45% were unchanged. SWT(UR) had a significant relation with contractile reserve (OR: 0.98; 95% CI: 0.97 to 0.99; p = 0.02).

CONCLUSIONS

CMR quantification of transmurality of infarcted myocardium allows the assessment of the potential of dysfunctional segments to improve in function during dobutamine of most segments. However, in segments with intermediate TEI, measurement of baseline contractility of the epicardial rim better identifies which segments maintain contractile reserve.

摘要

目的

本研究旨在利用低剂量多巴酚丁胺心脏磁共振（CMR）定量评估慢性完全闭塞（CTO）患者慢性功能障碍心肌的收缩储备，特别是在梗死透壁程度（TEI）为中间范围的节段。

背景

经皮冠状动脉介入治疗后，中间 TEI 节段功能障碍的恢复是可变的，难以预测，并且可能与未增强边缘的收缩力有关。

方法

51 例（平均年龄 60±9 岁，76%为男性）CTO 患者在基线和 35 例患者在随访时进行 CMR，以定量评估静息时 5 和 10μg/kg/min 多巴酚丁胺以及随访时的节段壁增厚（SWT），并进行延迟增强 CMR 以定量 TEI。根据 TEI、舒张末期壁厚度（EDWT）或未增强边缘厚度对功能障碍节段进行分层，并量化 SWT。根据基线未增强边缘的 SWT（SWT（UR））（<45%和>45%）进一步对中间 TEI（25%至 75%）节段进行分层，并量化 SWT。对于每个参数，计算预测收缩储备的比值比（OR）和诊断性能。

结果

EDWT>6mm、未增强边缘厚度>3mm 或 TEI<25%的功能障碍节段存在显著收缩储备；只有 TEI 与收缩储备有显著关系（OR：0.98；95%置信区间 [CI]：0.96 至 0.99；p=0.02）。在中间 TEI 节段（n=58）中，平均 SWT 无显著改善。然而，SWT（UR）<45%的节段显示出收缩储备并在随访中得到改善，而 SWT（UR）>45%的节段则无变化。SWT（UR）与收缩储备有显著关系（OR：0.98；95%CI：0.97 至 0.99；p=0.02）。