Hussain Shazia T, Paul Matthias, Morton Geraint, Schuster Andreas, Chiribiri Amedeo, Perera Divaka, Nagel Eike
University Hospitals of Leicester NHS Trust, Leicester, UK.
Luzerner Kantonsspital, Luzern, Switzerland.
Am J Cardiol. 2017 Dec 1;120(11):1913-1919. doi: 10.1016/j.amjcard.2017.08.002. Epub 2017 Sep 4.
Cardiovascular magnetic resonance (CMR) perfusion imaging and fractional flow reserve (FFR) assess myocardial ischemia. FFR measures the pressure loss across a stenosis determining hemodynamic significance but does not assess the area subtended by the stenotic vessel. CMR perfusion imaging measures the extent of myocardial blood flow reduction (=ischemic burden). Both techniques allow for continuous rather than categorical evaluation, but their relationship is poorly understood. This study investigates the relationship between the FFR value and the extent of myocardial ischemia. Forty-nine patients with angina underwent CMR perfusion imaging. FFR was measured in vessels with a visual diameter stenosis >40%. The extent of ischemia for each coronary artery was measured by delineating the perfusion defect on the CMR images and expressing as a percentage of the left ventricular myocardium. The correlation between the extent of ischemia measured by CMR and FFR was good (r = -0.85, p < 0.0005). The mean FFR value was 0.67 ± 0.17, and the mean perfusion defect was 8.9 ± 9.3%. An FFR value of ≥0.75 was not associated with ischemia on CMR. The maximum amount of ischemia (23.0 ± 1.5%) was found at FFR values 0.4 to 0.5. In patients with 1 vessel disease (49%), the mean ischemic burden was 15.3 ± 8.3%. In patients with 2 vessel diseases (18%), the mean ischemic burden was 26.0 ± 12%. Reproducibility for the measurement of ischemic burden was very good with a Kappa coefficient (k = 0.826, p = 0.048). In conclusion, there is good correlation between the FFR value and the amount of myocardial ischemia in the subtended myocardium.
心血管磁共振（CMR）灌注成像和血流储备分数（FFR）用于评估心肌缺血。FFR测量狭窄部位的压力损失以确定血流动力学意义，但不评估狭窄血管所覆盖的区域。CMR灌注成像测量心肌血流减少的程度（即缺血负担）。两种技术都允许进行连续而非分类评估，但它们之间的关系尚不清楚。本研究调查FFR值与心肌缺血程度之间的关系。49例心绞痛患者接受了CMR灌注成像检查。在目测直径狭窄>40%的血管中测量FFR。通过在CMR图像上勾勒灌注缺损并表示为左心室心肌的百分比来测量每条冠状动脉的缺血程度。CMR测量的缺血程度与FFR之间的相关性良好（r = -0.85，p < 0.0005）。平均FFR值为0.67±0.17，平均灌注缺损为8.9±9.3%。FFR值≥0.75与CMR上的缺血无关。在FFR值为0.4至0.5时发现最大缺血量（23.0±1.5%）。在单支血管病变患者（49%）中，平均缺血负担为15.3±8.3%。在双支血管病变患者（18%）中，平均缺血负担为26.0±12%。缺血负担测量的可重复性非常好，kappa系数为（k = 0.826，p = 0.048）。总之，FFR值与所覆盖心肌的心肌缺血量之间存在良好的相关性。
