Marques Koen M, Knaapen Paul, Boellaard Ronald, Westerhof Nico, Lammertsma Adriaan A, Visser Cees A, Visser Frans C
Department of Cardiology, VU University Medical Centre, De Boelelaan 1117, PO Box 7057, 1007 MB Amsterdam, The Netherlands.
Eur Heart J. 2007 Oct;28(19):2320-5. doi: 10.1093/eurheartj/ehm309. Epub 2007 Jul 26.
The present study compared microvascular resistance (MR) of viable myocardium in infarct areas with those in reference areas in patients with chronic myocardial infarction (MI).
In 27 patients, MR (ratio distal coronary pressure and flow) of reference and viable infarct areas was calculated at baseline and during hyperaemia. H2 15O positron emission tomography (PET) was used to provide myocardial blood flow measurements. In infarct regions, H2 15O PET solely measures flow in viable myocardium, excluding flow in scar tissue. Distal coronary pressure was measured with a pressure wire in the infarct-related and reference artery. The average time between PET study and infarction was 3.3+/-4.4 years. Mean hyperaemic distal coronary pressure was significantly lower in the infarct-related artery. MR varied considerably between patients and was significantly higher in infarct areas at baseline (135+/-38 vs. 118+/-29 mmHg mL min/mL; P<0.05), but not during hyperaemia (39+/-18 vs. 35+/-11 mmHg mL min/mL). The correlation between MR in infarct and reference areas was significant.
To determine MR, distal coronary pressure measurements should be used. Hyperaemic MR in viable myocardium within the infarcted area is not higher when compared with the reference area. This supports the application of the established fractional flow reserve cut-off value in the setting of chronic MI.
本研究比较了慢性心肌梗死（MI）患者梗死区域存活心肌与对照区域的微血管阻力（MR）。
对27例患者，在基线和充血期间计算对照区域和梗死存活区域的MR（冠状动脉远端压力与血流之比）。采用H2 15O正电子发射断层扫描（PET）测量心肌血流。在梗死区域，H2 15O PET仅测量存活心肌的血流，不包括瘢痕组织中的血流。用压力导丝测量梗死相关动脉和对照动脉的远端冠状动脉压力。PET研究与心肌梗死之间的平均时间为3.3±4.4年。梗死相关动脉的平均充血远端冠状动脉压力显著降低。患者之间的MR差异很大，梗死区域在基线时MR显著更高（135±38 vs. 118±29 mmHg·mL·min/mL；P<0.05），但在充血期间无显著差异（39±18 vs. 35±11 mmHg·mL·min/mL）。梗死区域与对照区域的MR之间存在显著相关性。
应采用测量冠状动脉远端压力来确定MR。梗死区域内存活心肌的充血MR与对照区域相比并不更高。这支持了在慢性心肌梗死情况下应用既定的血流储备分数临界值。
