From the Department of Cardiology, Clinical Sciences, Lund University, Skåne University Hospital, Lund (M.G., T.T., M.N., D.E.), the Departments of Cardiology and Radiology, Helsingborg Hospital, Helsingborg (L.S., S.-E.O.), the Department of Cardiology, Karlstad Hospital, Karlstad (M.D., H.O.), the Uppsala Clinical Research Center (P.Ö.) and Department of Medical Sciences (S.K.J.), Uppsala University, Uppsala, the Department of Cardiology, Sahlgrenska University Gothenburg (E.O.), the Department of Cardiology, Faculty of Health, Örebro University, Örebro (F.C., O.F.), the Department of Cardiology, St. Göran Hospital (P.L.), the Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet (J.J.), and the Unit of Cardiology, Capio St. Görans Sjukhus (J.J.), Stockholm, the Departments of Cardiology and of Medical and Health Sciences, Linköping University, Linköping (D.V., D.H., G.P.), the Department of Internal Medicine, Västmanland Hospital Västerås, Västerås (A.K.), the Department of Cardiology, Kalmar County Hospital, and Linnaeus University, Faculty of Health and Life Sciences, Kalmar (J.C.), the Department of Medicine, Sundsvall Hospital, Sundsvall (J.J.), and the Department of Cardiology, Halmstad Hospital, Halmstad (A.-C.K.) - all in Sweden; the Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark (E.H.C., L.J., M.M.); and the Department of Cardiology, Reykjavik University Hospital, Reykjavik, Iceland (I.J.G.).
N Engl J Med. 2017 May 11;376(19):1813-1823. doi: 10.1056/NEJMoa1616540. Epub 2017 Mar 18.
The instantaneous wave-free ratio (iFR) is an index used to assess the severity of coronary-artery stenosis. The index has been tested against fractional flow reserve (FFR) in small trials, and the two measures have been found to have similar diagnostic accuracy. However, studies of clinical outcomes associated with the use of iFR are lacking. We aimed to evaluate whether iFR is noninferior to FFR with respect to the rate of subsequent major adverse cardiac events.
We conducted a multicenter, randomized, controlled, open-label clinical trial using the Swedish Coronary Angiography and Angioplasty Registry for enrollment. A total of 2037 participants with stable angina or an acute coronary syndrome who had an indication for physiologically guided assessment of coronary-artery stenosis were randomly assigned to undergo revascularization guided by either iFR or FFR. The primary end point was the rate of a composite of death from any cause, nonfatal myocardial infarction, or unplanned revascularization within 12 months after the procedure.
A primary end-point event occurred in 68 of 1012 patients (6.7%) in the iFR group and in 61 of 1007 (6.1%) in the FFR group (difference in event rates, 0.7 percentage points; 95% confidence interval [CI], -1.5 to 2.8; P=0.007 for noninferiority; hazard ratio, 1.12; 95% CI, 0.79 to 1.58; P=0.53); the upper limit of the 95% confidence interval for the difference in event rates fell within the prespecified noninferiority margin of 3.2 percentage points. The results were similar among major subgroups. The rates of myocardial infarction, target-lesion revascularization, restenosis, and stent thrombosis did not differ significantly between the two groups. A significantly higher proportion of patients in the FFR group than in the iFR group reported chest discomfort during the procedure.
Among patients with stable angina or an acute coronary syndrome, an iFR-guided revascularization strategy was noninferior to an FFR-guided revascularization strategy with respect to the rate of major adverse cardiac events at 12 months. (Funded by Philips Volcano; iFR SWEDEHEART ClinicalTrials.gov number, NCT02166736 .).
瞬时无波比（iFR）是评估冠状动脉狭窄严重程度的指标。该指数已在小型试验中与血流储备分数（FFR）进行了测试，两种测量方法具有相似的诊断准确性。然而，与 iFR 使用相关的临床结果研究尚缺乏。我们旨在评估 iFR 在随后主要不良心脏事件的发生率方面是否不劣于 FFR。
我们使用瑞典冠状动脉血管造影和血管成形术登记处进行了一项多中心、随机、对照、开放标签临床试验入组。共有 2037 名稳定性心绞痛或急性冠状动脉综合征患者，其有指征进行生理引导的冠状动脉狭窄评估，随机分配接受 iFR 或 FFR 指导的血运重建。主要终点是手术后 12 个月内任何原因导致的死亡、非致死性心肌梗死或计划外血运重建的复合发生率。
iFR 组 1012 例患者中有 68 例（6.7%）和 FFR 组 1007 例患者中有 61 例（6.1%）发生主要终点事件（发生率差异为 0.7 个百分点；95%置信区间[CI]，-1.5 至 2.8；非劣效性 P=0.007；危险比，1.12；95%CI，0.79 至 1.58；P=0.53）；事件发生率差异的 95%CI 上限落在预设的非劣效性 3.2 个百分点的范围内。主要亚组的结果相似。两组间心肌梗死、靶病变血运重建、再狭窄和支架血栓形成的发生率无显著差异。FFR 组患者在手术过程中报告胸痛的比例明显高于 iFR 组。
在稳定性心绞痛或急性冠状动脉综合征患者中，iFR 指导的血运重建策略与 FFR 指导的血运重建策略相比，12 个月时主要不良心脏事件的发生率无差异。（由飞利浦 Volcano 资助；iFR SWEDEHEART ClinicalTrials.gov 编号，NCT02166736 ）。
