IMR Press / RCM / Volume 23 / Issue 11 / DOI: 10.31083/j.rcm2311361
Open Access Original Research
PCI Deferral Based on Fractional Flow Reserve or Optical Coherence Tomography: Two-Year Results of the Forza Trial
Show Less
1 Dipartimento di Scienze Cardiovascolari, Fondazione Policlinico Universitario A, Gemelli IRCCS, 00168 Roma, Italy
2 Dipartimento di Scienze Cardiovascolari , Università Cattolica del Sacro Cuore, 00168 Roma, Italy
3 Cardiologia e Unità terapia intensiva, Policlinico Casilino, 00169 Roma, Italy
*Correspondence: (Antonio Maria Leone)
These authors contributed equally.
Academic Editors: Manuel Martínez-Sellés, Grigorios Tsigkas, Athanasios Moulias and Anastasios Apostolos
Rev. Cardiovasc. Med. 2022, 23(11), 361;
Submitted: 4 June 2022 | Revised: 25 July 2022 | Accepted: 10 August 2022 | Published: 25 October 2022
(This article belongs to the Special Issue Intravascular imaging and Cardiovascular intervention)
Copyright: © 2022 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.

Backgroud: The “FFR or OCT Guidance to Revascularize Intermediate Coronary Stenosis Using Angioplasty” (FORZA) trial showed that in patients with angiographically intermediate coronary lesions (AICLs), optical coherence tomography (OCT) guidance of percutaneous coronary intervention (PCI) reduced the occurrence of the composite endpoint of major adverse cardiac events (MACE) or significant angina at 13 months, while fractional flow reserve (FFR) guidance was associated with a higher rate of medical management and with lower costs. Safety of PCI deferral when FFR >0.80 is known, while data on clinical outcomes using an OCT guidance are lacking. We assessed the safety of PCI deferral based on OCT findings. Methods: This is a subgroups analysis of the FORZA Trial focusing on the clinical outcome of patients in whom PCI was originally deferred. In details, patients with AICLs were randomized to FFR or OCT imaging. In the FFR arm, PCI was deferred if FFR was >0.80 while in the OCT arm in the absence of any of the following conditions: area stenosis >75%, or 50% to 75% with minimum lumen area <2.5 mm2 or plaque rupture. Angina status (evaluated using the Seattle Angina Questionnaire, SAQ), MACE (death, myocardial infarction, target vessel revascularization) and rate of patients treated with optimal medical therapy alone were assessed at 24 months. Results: From a total of 350 patients with 446 AICLs enrolled in the trial (176 randomized to FFR and 174 to OCT), based on the predefined FFR and OCT criteria, PCI was deferred in 119 patients (67.6%) in the FFR arm, and in 82 patients (47.1%) in the OCT arm. At 24-months follow-up, significant residual angina (defined as a value <90 on the angina frequency scale) was observed in 6 patients (5.0%) in the FFR arm, and in 6 patients (7.3%) in the OCT arm (p = 0.55). Rate of MACE was 10.9% in the FFR arm and 6.1% in the OCT arm (p = 0.32). The number of patients managed by optimal medical therapy alone was still significantly higher using FFR than OCT guidance also at 24 months (60.2% vs 44.2%, p = 0.0038). Conclusions: PCI-deferral based on OCT (using the FORZA trial criteria) is safe and associated with numerically less events at 24-months follow up. FFR guidance is still associated with a higher number of patients managed by optimal medical therapy alone.

fractional flow reserve
optical coherence tomography
personalized medicine
1. Introduction

Functional assessment of intermediate coronary stenoses by means of fractional flow reserve (FFR) has proven to be better than angiography alone in selecting lesions to be treated and in guiding percutaneous coronary intervention (PCI) [1, 2, 3]. In contrast, intracoronary imaging techniques, such as optical coherence tomography (OCT), despite useful in optimizing PCI, does not still play a clear role when it comes to choosing the lesions to treat [4, 5, 6]. The open-label, single-centre, prospective, randomized “FFR or OCT Guidance to Revascularize Intermediate Coronary Stenosis Using Angioplasty” (FORZA) trial [7] (NCT01824030) was therefore conducted in order to compare the clinical and economic implications of PCI-deferral of angiographically intermediate coronary lesions (AICLs) based on OCT evaluation or on FFR assessment. In the present report, the 24-months follow-up results of the subgroup of patients in which a strategy of FFR or OCT guided strategy of PCI deferral of the FORZA trial are presented.

2. Methods
2.1 Study Design

FORZA trial [7] enrolled three hundred and fifty consecutive patients with stable ischemic heart disease or stabilized (culprit lesion treated previously) acute coronary syndrome and evidence of at least one AICL, for a total of 446 AICL. AICL was defined as a coronary lesion with an angiographically estimated percentage diameter stenosis ranging from 30% and 80%.

Patients were randomized in a 1:1 fashion to the use of OCT guidance or FFR guidance for deferring or performing PCI. Specific inclusion and exclusion criteria were previously reported [7]. The study was approved by the ethics committee of our institution (internal code 6261/13), and all patients signed a dedicated informed consent form. The data that support the findings of this study are available from the corresponding author upon reasonable request. We have already published results at 1 and 13 months. We selected patients in whom PCI, based on FFR and OCT criteria, was initially deferred. In details, PCI was deferred when FFR was >0.80 or, in the OCT arm, in the absence of any of the following conditions: an area stenosis >75%, or 50% to 75% with minimum lumen area <2.5 mm2 or plaque rupture. The study flowchart is summarized in Fig. 1.

Fig. 1.

Study flow chart. AS, area stenosis; FFR, fractional flow reserve; MLA, minimal luminal area; OCT, optical coherence tomography; PCI, percutaneous coronary intervention; OMT, optical medical therapy.

2.2 Procedure Description

After placement of a guiding catheter at the coronary ostium, FFR or OCT assessments have been performed according to randomization as described previously [7]. Randomization was based on a computer-generated random series of numbers and took place through the opening of an envelope in which the treatment arm was reported. Both the operator and the patient were unblinded to the technique used.

2.3 Definition of Deferred Groups
2.3.1 FFR Deferred Arm

A 0.014-inch pressure-monitoring guidewire (Pressure Wire Certus or Aeris; Abbott Vascular, Abbott Park, IL, USA) was advanced beyond the AICL under radioscopic examination to calculate the lowest ratio of distal coronary pressure (Pd) divided by aortic pressure (Pa) after achievement of hyperaemia using adenosine. Lesions were deferred when the FFR values was >0.80. In contrast, when FFR was 0.80, PCI was performed with the aim of achieving a post-stenting FFR 0.90 (Fig. 2).

Fig. 2.

The FORZA criteria for AICLs revascularization based on FFR or OCT. (A) FFR 0.80. (B) AS% 75%. (C) AS% from 50% to 75% with MLA <2.5 mm2. (D) AS% from 50% to 75% and plaque ulceration. AICLs, angiographically intermediate coronary lesions; FFR, fractional flow reserve; OCT, optical coherence tomography; AS, area stenosis; MLA, minimal lumen area.

2.3.2 OCT Deferred Arm

OCT images were acquired (after intracoronary administration of nitro-glycerine) at the site of the AICL with commercially available systems (C7 System, LightLab Imaging/St. Jude Medical, Westford, Massachusetts; and, after its availability, Optis System, Abbott Vascular) after the OCT catheter (C7 Dragonfly, LightLab Imaging/St. Jude Medical; and Dragonfly Optis, Abbott Vascular) was advanced to the distal end of the target lesion. The entire length of the region of interest was evaluated: minimal luminal area (MLA) (defined as cross-sectional area at the smallest luminal area level), proximal reference luminal area (RLA) (defined as the cross section at the frame with largest lumen within 10 mm proximal to MLA and before any major side branch), distal RLA (defined as the cross section at the frame with largest lumen within 10 mm distal to MLA and before any major side branch), and mean RLA (defined as [proximal RLA + distal RLA]/2). On the basis of these parameters, percentage of area stenosis (AS) was calculated using the following formula: (mean RLA - MLA) / mean RLA × 100. Plaque rupture (also called ulceration) was defined as a recess in the plaque beginning at the luminal-intimal border [8].

PCI was deferred in the absence of any of the following conditions: (1) area stenosis >75%; (2) area stenosis between 50% and 75% with minimum lumen area <2.5 mm2; (3) plaque rupture (Fig. 2).

If at least 1 of the previous criteria occurred, operator proceeded to PCI. In patients who underwent revascularization, OCT was used also to guide and optimize PCI results. Optimization was performed in the presence of major stent malapposition (defined as distance between strut and vessel wall >350 μm or <350 μm and >200 μm for a length >600 μm), major underexpansion (in-stent minimal cross-sectional area <75% of the RLA) or major edge dissection (defined as length >600 μm).

2.4 Study Endpoints

The study evaluates the clinical end point of “angina status” using the significant residual angina (<90 score at SAQ angina frequency scale) plus major adverse cardiovascular events (MACE), defined as the occurrence of death, spontaneous myocardial infarction (MI), and target vessel revascularization at 24 months. The prevalence of the individual components of the primary combined endpoint were considered secondary endpoints. The full description of each clinical outcomes is described in the main paper [7].

Other outcomes of special interest were the SAQ value and the variation of angina symptoms after the 2 years of follow-up as well the overall number of medically managed patients. In addition, radioscopic time (min), amount of contrast medium (mL), post procedural length of hospitalization (days) and estimated costs associated with the two different strategies were evaluated as further secondary endpoints.

The total costs, including the cost of the first and any unplanned hospitalization after discharge was evaluated and compared between arms. Details for procedural and hospitalization cost evaluation have been previously reported [7].

This sub-study was designed to test the hypothesis that OCT imaging could be an acceptable alternative to FFR for deferral patients with AICLs after 24 months of follow-up.

2.5 Statistical Analysis

Categorical variables were expressed as percentages and analyzed by Fisher’s exact test. Continuous variables (including clinical and economical end points) are expressed as mean ± SD and/or median [interquartile range] and compared using the paired and unpaired t-test or the nonparametric Wilcoxon and Mann–Whitney U-test, as appropriate, after having tested normality using the Kolmogorov–Smirnov test. Differences were considered significant with p < 0.05. Missing values were not counted, and all analysis were based only on valid values and performed by intention to treat using GraphPad Prism (version 5.0; GraphPad Software Inc., San Diego, CA, USA) and SPSS software (v.21.0; SPSS, Inc., Chicago, IL, USA).

3. Results

The characteristics of the patients and lesions enrolled in the two study arms are showed in Tables 1,2 [8]. In the FFR group, PCI was deferred in 119 patients (67.6%) vs 82 (47.1%) in the OCT group. Deferred patients according to FFR or OCT were fairly similar (no statistically significant difference in baseline clinical characteristic except for a significant higher statin and oral anticoagulation use in patients evaluated by OCT). In the OCT group, higher prevalence of multivessel disease and LCX involvement were noted. Mean FFR was 0.87 ± 0.05 in deferred FFR group while mean minimal lumen area was 3.74 ± 1.94 mm2 and area stenosis 53 ± 18% in the deferred OCT group.

Table 1.Patients clinical characteristics.
All patients FFR OCT p value
n = 201 n = 119 n = 82
Age 68 ± 9 70 ± 10 68 ± 9 0.41
Male gender 89 (74.6%) 80 (67.2%) 66 (55.5%) 0.22
BMI 27 ± 4 27 ± 4 27 ± 4 0.5
Risk factors
Diabetes 67 (33%) 39 (32.8%) 28 (34.1%) 0.88
Hypertension 170 (84.6%) 102 (85.7%) 68 (82.9%) 0.69
Dyslipidemia 141 (70.1%) 81 (68.1%) 60 (73.2%) 0.54
Smoking 73 (36.3%) 47 (39.5%) 26 (31.7%) 0.24
CKD 40 (19.9%) 26 (21.8%) 14 (17.1%) 0.47
Previous history
Previous PCI 83 (41.3%) 51 (42.9%) 32 (39%) 0.27
Previous CABG 4 (2.0%) 2 (1.73%) 2 (2.4%) 1
Previous MI 44 (21.9%) 20 (16.8%) 24 (29.3%) 0.06
Clinical presentation
Stable ischemic heart disease 158 (78.6%) 94 (79%) 64 (78.0) 0.86
ACS 43 (21.4%) 25 (21%) 18 (21.9%) 0.68
Unstable angina 28 (13.9%) 16 (13.4%) 12 (14.6%) 0.84
NSTEMI 14 (7.0%) 9 (7.6%) 5 (6.1%) 0.78
STEMI 1 (0.5%) 0 (0%) 1 (1.2%) 0.41
LVEF (%) 57 ± 8 57 ± 7 58 ± 9 0.55
Seattle Angina Questionnaire 83 ± 22 84 ± 21 85 ± 22 0.62
Therapy at discharge
Aspirin 165 (82.1%) 97 (81.5%) 68 (82.9%) 0.24
P2Y12 inhibitors 87 (43.3%) 48 (40.3%) 39 (47.6%) 0.31
Beta blockers 145 (72.1%) 80 (67.2%) 65 (79.3%) 0.65
Calcium channel blockers 51 (25.4%) 27 (22.7%) 24 (29.3%) 0.63
ACE inhibitors/ARB 145 (72.1%) 86 (72.3%) 59 (71.9%) 1
Statin 162 (80.6%) 89 (74.8%) 73 (89.0%) 0.02
Nitrates 14 (7.0%) 7 (5.9%) 7 (8.5%) 0.78
Ranolazine 16 (8.0%) 9 (7.6%) 7 (8.5%) 1
Diuretics 56 (27.9%) 32 (26.9%) 24 (29.3%) 1
Oral anticoagulant 24 (11.9%) 9 (7.6%) 15 (18.3%) 0.03
FFR, fractional flow reserve; OCT, optical coherence tomography; BMI, body mass index; CKD, chronic kidney disease; PCI, percutaneous coronary intervention; CABG, coronary artery bypass grafting; MI, myocardial infarction; ACS, acute coronary syndromes; NSTEMI, non ST elevation myocardial infarction; STEMI, ST elevation myocardial infarction; LVEF, left ventricular ejection fraction; ACE, Angiotensin-converting enzyme; ARB, angiotensin receptor blocker.
Table 2.Lesions characteristics.
FFR OCT p value
151 lesions 102 lesions
Multivessel disease 27 (22.7%) 32 (39%) 0.018
Studied lesions 151 102 1
Single lesion studied 87 (57.6%) 66 (64.7%) 0.36
>1 lesion studied 64 (42.4%) 36 (35.3%)
Target lesion
LAD 93 (%) 64 (%)
LCX 25 (%) 10 (%) 0.02
RCA 28 (%) 20 (%)
Visual diameter stenosis (%) 51 ± 8 52 ± 8 0.19
Baseline findings according to technique of randomization
Resting Pd/Pa 0.95 ± 0.03 N/A
FFR 0.87 ± 0.05 N/A
MLA (mm2) N/A 3.74 ± 1.94
AS (%) N/A 53 ± 18
FFR, fractional flow reserve; OCT, optical coherence tomography; LAD, left anterior descending artery; LCX, left circumflex artery; RCA, right coronary artery; MLA, minimal lumen area; AS, area stenosis.

Bifurcation lesions were slightly more prevalent in the OCT arm, without significant differences in terms of prevalence and revascularization adopted strategy (single stent or double stents) (Table 3).

Table 3.Bifurcation Lesions and treatment FORZA trial.
FFR OCT p value
225 lesions 221 lesions
Bifurcation PCI (%) 17 (7.5) 24 (10.9) 0.24
Single stent treatment (%) 13 (5.8) 22 (9.9) 0.31
Double stent treatment (%) 4 (1.8) 2 (0.9) 0.08
FFR, fractional flow reserve; OCT, optical coherence tomography; PCI percutaneous coronary intervention.

Radioscopic time, dose area product (DAP), consumption of contrast medium and postprocedural length of stay were numerically, but not significantly, higher in OCT than in FFR group (Table 4).

Table 4.Overall procedural results.
FFR OCT p value
119 patients 82 patients
151 lesions 102 lesions
Radioscopic time (min) 13.1 ± 7 14.4 ± 23.6 0.58
DAP (mGy*cm2) 16127 ± 21387 19645 ± 24891 0.29
Contrast media (mL) 185 ± 90 202 ± 99 0.21
Post procedural length of stay (days) 2.5 ± 1.5 3.0 ± 3.8 0.21
FFR, fractional flow reserve; OCT, optical coherence tomography; DAP, dose area product.

The two groups had a similar value of frequency of angina at SAQ at enrolment and both groups improved similarly at 24 months follow-up (from 82 ± 21 to 98 ± 7 in FFR, p < 0.001 and from 87 ± 20 to 98 ± 5 in OCT, p < 0.001; delta SAQ in FFR 16 ± 20 vs delta SAQ in OCT 10 ± 22, p = 0.09) (Table 5). More importantly, the prevalence of persisting significant angina (defined as <90 in frequency scale of SAQ) was similar in FFR and OCT deferred patients (5% vs 7.3%, p = 0.55) (Table 5). Overall, after 24 months of follow up after the index procedure with eventual PCI deferral, the rate of patients managed with optimal medical therapy alone was still significantly higher in FFR group in comparison to OCT (60% vs 44.2%, p = 0.004) (Fig. 3). As shown in Fig. 4, 24-month MACE were numerically (albeit not statistically significant) higher in FFR arm (10.9% vs 6.1%). Not significant differences were observed in terms of individual endpoints between groups (TVR 7.5% FFR vs 2.4% OCT, p = 0.20, MI 2.5% FFR vs 0% OCT, p = 0.27, death 2.5% FFR vs 3.7% OCT, p = 0.68) (Figs. 4,5). Such additional events caused further hospitalizations and procedures during the 24 months follow-up so that costs (which were significantly lower at baseline with FFR) were not statistically significant different between the FFR and OCT deferred patients at 24 months (2904 ± 2028 vs 3387 ± 2092 euros, p = 0.10) (Fig. 6).

Fig. 3.

Rate of patients managed with optimal medical therapy alone. FFR, fractional flow reserve; OCT, optical coherence tomography.

Fig. 4.

Prevalence of different endpoints and Kaplan Meier curves for MACE. MACE, major cardiovascular events; SAQ, Seattle Angina Questionnaire; FFR, fractional flow reserve; OCT, optical coherence tomography.

Fig. 5.

Kaplan Meier curves for Death, myocardial infarction (MI) and Target vessel revascularization (TVR). Panel A (Death), Panel B (MI) and Panel C (TVR).

Fig. 6.

Costs for patients managed with FFR and OCT at baseline and at 24-month follow-up (in euros). FFR, fractional flow reserve; OCT, optical coherence tomography.

Table 5.Overall endpoints results.
Event FFR (N = 119) OCT (n = 82) p value
Death 3 (2.5%) 3 (3.7%) 0.68
Myocardial infarction 3 (2.5%) 0 (0%) 0.27
Death/MI 6 (5%) 2 (2.4%) 0.48
TVR 9 (7.5) 2 (2.4%) 0.20
MACE 13 (10.9%) 5 (6.1%) 0.32
TVF 11 (9.2%) 4 (4.9%) 0.29
SAQ<90 6 (5%) 6 (7.3%) 0.55
MACE + angina 19 (16%) 10 (12.1%) 0.54
Optimal Medical Therapy (% of the starting population)
Baseline 119 (67.6%) 82 (47.1%) <0.001
13 months 110 (62.5%) 80 (46.0%) <0.001
24 months 106 (60.2%) 77 (44.2%) 0.0038
Cost at baseline 2356 ± 762 3230 ± 1903 <0.001
Cost at follow up 2904 ± 2028 3387 ± 2092 0.10
FFR, fractional flow reserve; OCT, optical coherence tomography; MI, myocardial infarction; TVR, target vessel revascularization; MACE, major cardiovascular events; TVF, target vessel failure; SAQ, Seattle Angina Questionnaire.
4. Discussion

A strategy of safe deferral of revascularization is possible only when spontaneous cardiovascular events are lower than the predicted events due to the procedure. A large body of evidence supports the safety of PCI deferral in case of FFR >0.80 [1] and current guidelines on PCI recommend the use of FFR (or instantaneous wave-free ratio) to assess the hemodynamic relevance of intermediate-grade coronary stenoses. On the contrary, data on clinical outcomes associated with deferral of PCI based on OCT findings are scarce and no standard anatomic references are described to evaluate the relevance of intermediate stenoses. Thus, we performed a novel analysis of the FORZA trial after an extended follow-up time of 24 months, comparing the subgroup of patients in which PCI was originally deferred based on FFR or OCT.

So far, we observed that FFR was associated with lower costs and higher medical management rate while OCT reduced the composite endpoint of major adverse cardiac events (MACE) or significant angina at 13-month [9, 10].

At 24-month of follow up FFR was still associated with a larger number of conservatively treated lesions translating into a larger and significantly higher number of medically managed patients. The high medical management rate and the overall low number of events confirmed FFR as the best and safe strategy to defer PCI.

On the other hand, the higher rate of performed PCI in the OCT arm was in line with the old previous studies, showing that visual assessment at the angiography [2], as well anatomical findings obtained by IVUS, were constantly associated with a higher rate of anatomically significant stenosis in comparison to functionally significant stenosis according to FFR.

Differently from what initially assumed in the main paper regarding the safety of “conservative” OCT criteria, a non-significant difference of MACE between the functional and imaging deferred arms was documented, with numerically less events in the OCT group.

In details, a similar death rate and a less rate of MI and TVR in OCT patients were detected underling the ability of imaging evaluation to characterize the natural history of coronary lesions, excluding the presence of high-risk features of untreated plaques and resulting a safe technique to defer PCI without impact on patient’s prognosis. On the other hand, the non-significant increase in TVR and hospitalizations in FFR arm affected total costs, which became not more statistically different at extended follow up of 24 months.

A similar value of frequency of angina at SAQ and, more importantly, a similar prevalence of persisting significant angina was noted between two arms. These data disclosed the ability of the “conservative” OCT criteria to be associated with hemodynamic significance of lesions and to predict stenosis-related myocardial ischemia in a way like FFR. We suggested a new role of pre-PCI OCT: not only to characterize coronary lesions and correctly select PCI materials in a “imaging-guided PCI” but also as an acceptable alternative for deferral angioplasty in intermediate lesions.

This study represents the first evidence that an anatomical guidance using OCT imaging, applying the simple FORZA criteria, could be an acceptable alternative to the physiological reference standard also for deferral of AICLs.

5. Future Directions

These are the first data supporting the use of OCT to safely defer treatment of AICL taking FFR as the gold standard. Despite the quite limited number of patients enrolled in this sub-analysis of the FORZA trial could limit the ability to draw definitive conclusions about safety of OCT to safely defer treatment of AICL, the numerically lower rate of event seen in comparison to FFR seems quite reassuring. We believe that an imaging evaluation of intermediate coronary lesions could be a comparable strategy to defer PCI like FFR, and at the same time we suppose a possible link between morphologic plaque assessment and hemodynamic significance of lesions in order to predict stenosis-related myocardial ischemia. We strongly support further investigations in this field, in particular more data are needed to assess the correlation between anatomical and functional indexes in order to predict MACE and myocardial ischemia.

6. Limitations

Our data derived from a single centre study, with a small sample size and the result should be regarded as hypotheses generating. It was conducted locally without either a structured clinical research organization or an independent clinical events committee. The use of unconventional OCT criteria has to be acknowledged in light of the lack of clear data at the time of design of the trial [7]. However, after initiation of the study, these criteria were validated in comparison to FFR in a retrospective cohort of patients assessed with both FFR and OCT [11] and a recent randomized trial showed a safe profile of the OCT criteria to defer or perform PCI [12]. FFR assessment was made in according to the best clinical practise, however a clear definition of diffuse versus focal disease was not available because of the absence of new tools (PPG index) [13] at the start of the study. However, pullback manoeuvres were performed both in the pre and post PCI phase to assess the pressure drop distribution along the vessel. Total procedural time was not recorded but we evaluated the “procedural radioscopic time” as a surrogate, less dependent by logistic or procedural confounders.

7. Conclusions

The 24-months follow-up results of the FORZA trial, the first prospective randomized trial comparing OCT and FFR to guide PCI decision and performance in AICLs, showed that deferral of PCI based on OCT is clinically safe as compared with the (contemporary gold-standard) FFR-guided approach. Over 2 years, FFR-guidance warranted higher rate of optimal medical therapy management alone as compared with OCT-guidance.

Author Contributions

AML and FBur—conception and design, analysis and interpretation of data, drafting, and revising critically the manuscript for important intellectual content; CA and DG—analysis of data and drafting of the manuscript; GZ, AZ, FDG, FBia and RV—collection, analysis, and interpretation of data; CT and FC—important intellectual contribution; All authors contributed to the article and approved the submitted version.

Ethics Approval and Consent to Participate

The studies involving human participants were reviewed and approved by Comitato Etico del Policlinico Gemelli di Roma (number 6261/13). The patients/participants provided their written informed consent to participate in this study.


We would like to express our gratitude to the peer reviewers for their opinions and suggestions, and to all those who helped us with writing of this manuscript.


The FORZA TRIAL was funded by internal Academic Grants (Bando Linea D. 1105536). The authors also thank the Italian Ministry of Health for the funding within the “Ricerca corrente 2021” project.

Conflict of Interest

A.M.L. received speaking honoraria from Abbott, Medtronic, Abiomed and from Bracco Imaging, F.B, C.T and C.A received speaker’s fees from Abbott, Medtronic, and Abiomed. G.Z., A.Z., D.G., F.D.G., F.B., R.V. and F.C have no conflicts of interest. Antonio Maria Leone is serving as one of the Editorial Board members of this journal. We declare that Antonio Maria Leone had no involvement in the peer review of this article and has no access to information regarding its peer review. Full responsibility for the editorial process for this article was delegated to Manuel Martínez-Sellés, Grigorios Tsigkas, Athanasios Moulias and Anastasios Apostolos.

Publisher’s Note: IMR Press stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Neumann F, Sousa-Uva M, Ahlsson A, Alfonso F, Banning AP, Benedetto U, et al. 2018 ESC/EACTS Guidelines on myocardial revascularization. EuroIntervention. 2019; 14: 1435–1534.
Van Nunen LX, Zimmermann FM, Tonino PAL, Barbato E, Baumbach A, Engstrom T, et al. Fractional flow reserve versus angiography for guidance of PCI in patients with multivessel coronary artery disease (FAME): 5‐year follow‐up of a andomized controlled trial. Lancet. 2015; 386: 1853–1860.
Xaplanteris P, Fournier S, Pijls NHJ, Fearon WF, Barbato E, Tonino PAL, et al. Five‐year outcomes with PCI guided by fractional flow reserve. The New England Journal of Medicine. 2018; 379: 250–259.
Imola F, Mallus M, Ramazzotti V, Manzoli A, Pappalardo A, Di Giorgio A, et al. Safety and feasibility of frequency domain optical coherence tomography to guide decision making in percutaneous coronary intervention. EuroIntervention. 2010; 6: 575–581.
Meneveau N, Souteyrand G, Motreff P, Caussin C, Amabile N, Ohlmann P, et al. Optical Coherence Tomography to Optimize Results of Percutaneous Coronary Intervention in Patients with Non–ST-Elevation Acute Coronary Syndrome. Circulation. 2016; 134: 906–917.
Jones DA, Rathod KS, Koganti S, Hamshere S, Astroulakis Z, Lim P, et al. Angiography alone versus angiography plus optical coherence tomography to guide percutaneous coronary intervention: outcomes from the Pan‐London PCI Cohort. JACC Cardiovascular Interventions. 2018; 11: 1313–1321.
Burzotta F, Leone AM, De Maria GL, Niccoli G, Coluccia V, Pirozzolo G, et al. Fractional flow reserve or optical coherence tomography guidance to revascularize intermediate coronary stenosis using angioplasty (FORZA) trial: study protocol for a randomized controlled trial. Trials. 2014; 15: 140.
Tearney GJ, Regar E, Akasaka T, Adriaenssens T, Barlis P, Bezerra HG, et al. Consensus standards for acquisition, measurement, and reporting of intravascular optical coherence tomography studies: a report from the International Working Group for Intravascular Optical Coherence Tomography Standardization and Validation. Journal of the American College of Cardiology. 2010; 59: 1058–1072.
Burzotta F, Leone AM, Aurigemma C, Zambrano A, Zimbardo G, Arioti M, et al. Fractional Flow Reserve or Optical Coherence Tomography to Guide Management of Angiographically Intermediate Coronary Stenosis. JACC: Cardiovascular Interventions. 2020; 13: 49–58.
Leone AM, Burzotta F, Aurigemma C, De Maria GL, Zambrano A, Zimbardo G, et al. Prospective Randomized Comparison of Fractional Flow Reserve Versus Optical Coherence Tomography to Guide Revascularization of Intermediate Coronary Stenoses: one-Month Results. Journal of the American Heart Association. 2019; 8: e012772.
Burzotta F, Nerla R, Hill J, Paraggio L, Leone AM, Byrne J, et al. Correlation between frequency-domain optical coherence tomography and fractional flow reserve in angiographically-intermediate coronary lesions. International Journal of Cardiology. 2018; 253: 55–60.
Khurwolah MR, Meng H, Wang Y, Wang L, Kong X. Safety and efficacy of frequency-domain optical coherence tomography in evaluating and treating intermediate coronary lesions. World Journal of Cardiology. 2018; 10: 222–233.
Collet C, Sonck J, Vandeloo B, Mizukami T, Roosens B, Lochy S, et al. Measurement of Hyperemic Pullback Pressure Gradients to Characterize Patterns of Coronary Atherosclerosis. Journal of the American College of Cardiology. 2019; 74: 1772–1784.
Back to top