Tahir Hassan, Livesay James, Fogelson Benjamin, Baljepally Raj
Department of Cardiology, Heart Lung Vascular Institute, University of Tennessee Medical Center, Knoxville, TN, USA.
Cardiol Res. 2021 Apr;12(2):117-125. doi: 10.14740/cr1230. Epub 2021 Feb 23.
Instantaneous wave-free ratio (iFR)-guided physiological assessment has been shown to be non-inferior to fractional flow reserve (FFR)-guided assessment for deciding best treatment strategy for angiographically intermediate stenosis. The diagnostic accuracy of iFR compared to FFR reported in various studies is around 80%. Many factors can lead to iFR/FFR discordance, though underlying physiological mechanism of discordance and its associated factors have not been fully evaluated. The effect of left ventricle end diastolic pressure (LVEDP) on iFR/FFR discordance is unknown and needs further evaluation.
We performed a single center, non-randomized, both retrospective and prospective study. A total of 65 patients with intermediate coronary stenosis undergoing physiological assessment were included in the study. Patients were assigned to two groups (normal LVEDP and high LVEDP group) based on LVEDP cutoff of 15 mm Hg. iFR and FFR were measured for each patient and iFR/FFR results were compared between the two groups.
A significantly large number of patients in elevated LVEDP group had iFR/FFR discordance compared to normal LVEDP group (42.8% vs. 6.7%, P = 0.001). More patients with acute coronary syndrome (ACS) had discordance compared to stale coronary artery disease (CAD) patients (53% vs. 15%, P = 0.003).
Elevated LVEDP can affect iFR and FFR measurements and can lead to discordance. Further studies are required to determine effect of elevated LVEDP on iFR/FFR discordance and whether such discordance is clinically relevant. "Normal range" iFR results should be cautiously interpreted in patients with elevated LVEDP, especially those with ACS.
对于决定血管造影显示为中度狭窄病变的最佳治疗策略，瞬时无波比值（iFR）引导下的生理评估已被证明不劣于血流储备分数（FFR）引导下的评估。在各项研究中报道的iFR与FFR相比的诊断准确性约为80%。许多因素可导致iFR/FFR不一致，尽管不一致的潜在生理机制及其相关因素尚未得到充分评估。左心室舒张末期压力（LVEDP）对iFR/FFR不一致的影响尚不清楚，需要进一步评估。
我们进行了一项单中心、非随机、回顾性和前瞻性研究。共有65例中度冠状动脉狭窄且正在接受生理评估的患者纳入本研究。根据LVEDP临界值15 mmHg将患者分为两组（正常LVEDP组和高LVEDP组）。对每位患者测量iFR和FFR，并比较两组之间的iFR/FFR结果。
与正常LVEDP组相比，高LVEDP组中有大量患者存在iFR/FFR不一致（42.8%对6.7%，P = 0.001）。与陈旧性冠状动脉疾病（CAD）患者相比，更多急性冠状动脉综合征（ACS）患者存在不一致（53%对15%，P = 0.003）。
LVEDP升高可影响iFR和FFR测量，并可导致不一致。需要进一步研究以确定LVEDP升高对iFR/FFR不一致的影响以及这种不一致是否具有临床相关性。对于LVEDP升高的患者，尤其是ACS患者，应谨慎解释“正常范围”的iFR结果。
