Fractional Flow Reserve Aids Decision Making for Intermediate Coronary Lesions: 1-Month Data from FORZA Study

Mandana Chitsazan, M.D.
By Mandana Chitsazan, M.D. on

Compared with optical coherence tomography (OCT), fractional flow reserve (FFR) was associated with a higher percentage of medical therapy, lower risk of acute kidney injury, shorter hospital stay, and reduced costs at one month among patients with intermediate coronary lesions. The study by Leone et al., recently published in the Journal of American Heart Association, revealed.

Although practice guidelines recommend FFR for assessing the hemodynamic relevance of moderate coronary stenosis, its role in optimizing percutaneous coronary intervention (PCI) is not well established. On the other hand, OCT guidance for optimizing stent implantation is upgraded to a Class IIa recommendation in current guidelines; however, its role in selecting the target lesion for revascularization remains unclear.

The FORZA study (Fractional Flow Reserve versus Optical Coherence Tomography to Guide RevasculariZAtion of Intermediate Coronary Stenoses) sought to compare the clinical and economic implications of FFR versus OCT guidance in the management of patients with angiographically intermediate coronary lesions (AICLs). FORZA study was an open‐label, single‐center, prospective, randomized trial comparing the costs and rate of adverse clinical outcomes among patients with stable or stabilized ischemic heart disease and at least one AICL, defined as a lesion with a visually estimated percentage diameter stenosis between 30% and 80%. Patients were randomly allocated to FFR or OCT guidance at a 1:1 ratio.

The primary endpoint of FORZA study was the composite of significant residual angina or major adverse cardiovascular events (MACE). Significant residual angina was defined as a score of <90 on the angina frequency scale from the Seattle Angina Questionnaire (SAQ). MACE was defined as the occurrence of death, spontaneous type 1 myocardial infarction (MI), and target vessel revascularization.

In the present analysis of one-month data, additional endpoints included the rate of lesions and patients treated with medical therapy alone, amount of contrast medium, rate of contrast‐induced acute kidney injury (CI‐AKI), postprocedural release of markers of myonecrosis, rate of periprocedural (type 4a) MI, and total costs (including the cost of consumables, post‐PCI hospitalization, and unplanned procedure or rehospitalization related to the index procedure).

A total of 350 patients were enrolled and randomized to FFR (N=176) or OCT (N=174) guidance from March 2013 to May 2018. In general, the two groups were balanced for baseline characteristics including age (68±10 vs. 69±9 years), male sex (71.6% vs. 77.6%), stable ischemic heart disease on presentation (79.0% vs. 82.2%), left ventricular ejection fraction (60±8% vs. 56±9%), frequency of angina at SAQ (83±21% vs. 83±24%), multivessel disease (52.3% vs. 47.7%), and diameter stenosis (51±8% vs. 52±8%).

FFR guidance was associated with a higher percentage of lesions (71.0% vs. 49.3%; P=0.061) and patients (67.7% vs. 41.1%; P<0.0001) treated with medical therapy alone than OCT guidance. Patients in the FFR group had a lower dose of contrast media (245±137 vs. 280±129 mL; P=0.004), less increase in creatinine (0.02±0.18 vs. 0.08±0.25 mg/dL; P=0.04), a lower rate of CI-AKI (1.7% vs. 8.6%; P=0.034), and lower number of balloon (0.74±1.48 vs. 1.45±1.85; P<0.0001) or stent (0.33±0.57 vs. 0.64±0.70; P<0.0001) per patient. There was no difference in the level of post‐PCI troponin T (0.25±0.82 vs. 0.45±1.82 ng/mL; P=0.11) or the incidence of type 4 MI (1.7% vs. 2.3%; P=0.72).

At one month, the rates of the primary endpoint (7.4% vs. 8.0%; P=0.84), significant residual angina (6.8% vs. 8.0%; P=0.69), and MACE (0.6% vs. 0.0%; P=1.00) were comparable between the two groups. Compared to OCT guidance, FFR was associated with a trend toward shorter hospitalization (2.8±2.1 vs. 3.8±7.3 days; P=0.078) and significantly lower total costs (2831±1288 vs. 4292±3844 euros; P<0.001).

“These novel data are clinically relevant given that they provide new support for the use of FFR in the decision‐making process of patients with AICL. The possible clinical impact of the higher number of PCIs performed on the bases of OCT has to be evaluated at longer‐term follow‐up.” – Dr. Leone et al.

The study has several limitations. First, the criteria for revascularization were unconventional and may not reflect routine clinical practice. Second, the number of MACE events in this study was too small to draw an inference. Last, the study disclosed that only 47.5% and 64.7% of FFR-guided and OCT-guided patients attained optimal results on the post-stenting assessment, which underscores the unmet need for technical refinements of both approaches.

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