Trans-Stent FFR Gradient as a Modifiable Integrant in Predicting Long-Term Target Vessel Failure

Angiography-derived fractional flow reserve versus intravascular ultrasound to guide percutaneous coronary intervention in patients with coronary artery disease (FLAVOUR II): a multicentre, randomised, non-inferiority trial

BACKGROUND

Revascularisation decisions based on angiography-derived fractional flow reserve (FFR) or optimisation of stent implantation with intravascular ultrasound yield superior clinical outcomes compared with percutaneous coronary intervention (PCI) guided by angiography alone. However, the differences in outcomes when a single approach is used for both purposes remain unclear. We aimed to assess the non-inferiority of angiography-derived FFR versus intravascular ultrasound guidance in terms of clinical outcomes at 12 months in patients with angiographically significant stenosis.

METHODS

This investigator-initiated, open-label, multicentre, randomised, non-inferiority trial, which was done in 22 centres in China, enrolled patients aged 18 years or older with suspected ischaemic heart disease and with at least 50% stenosis in epicardial coronary arteries measuring at least 2·5 mm by visual estimation on coronary angiography. Patients were randomly assigned (1:1) to undergo PCI guided by either angiography-derived FFR or intravascular ultrasound, including revascularisation decisions and optimisation of the stent implantations based on prespecified PCI criteria and optimal PCI goals. Use of both modalities simultaneously was not permitted. Randomisation as performed using a web-based program and stratified based on the trial centre and the presence or absence of diabetes. The primary outcome was a composite of death, myocardial infarction, or revascularisation at 12 months in the intention-to-treat population, and the non-inferiority margin was 2·5 percentage points. This trial is registered with ClinicalTrials.gov, NCT04397211; long-term follow-up is ongoing.

FINDINGS

Between May 29, 2020, and Sept 20, 2023, 1872 patients were enrolled. After 33 patients withdrew, 923 patients were randomly assigned to the angiography-derived FFR group and 916 to the intravascular ultrasound group. Median age of the study population was 66·0 years (IQR 58·0-72·0), and 1248 (67·9%) patients were male and 591 (32·1%) were female. Revascularisation was performed in 688 (69·5%) of 990 target vessels in the angiography-derived FFR group and 797 (81·0%) of 984 target vessels in the intravascular ultrasound group. At a median follow-up of 12 months (IQR 12-12), the primary outcome event occurred in 56 patients in the angiography-derived FFR group and 54 patients in the intravascular ultrasound group (6·3% vs 6·0%, absolute difference 0·2 percentage points [upper boundary of one-sided 97·5% CI 2·4], pnon-inferiority=0·022; hazard ratio 1·04 [95% CI 0·71 to 1·51]). Mortality did not differ between the two groups (1·8% in the angiography-derived FFR group vs 1·3% in the intravascular ultrasound group, absolute difference 0·4 percentage points [95% CI -0·7 to 1·6]; hazard ratio 1·34 [0·63 to 2·83], p=0·45). The incidence of recurrent angina was low in both groups: 26 (2·8%) of 923 patients in the angiography-derived FFR group and 35 (3·8%) of 916 patients in the intravascular ultrasound group.

INTERPRETATION

The angiography-derived FFR-guided comprehensive PCI strategy, encompassing revascularisation decision making and stent optimisation, was non-inferior to intravascular ultrasound guidance. This finding might have implications for future guidelines on its role and application.

FUNDING

National Natural Science Foundation of China, The Key R & D Projects of Zhejiang Province, and the RCT Program from The Second Affiliated Hospital of Zhejiang University School of Medicine.

Prognostic implications of increased and final quantitative flow ratios in patients treated with drug-coated balloons physiological evaluation after DCB in de novo lesions

BACKGROUND

Few studies investigated the implications of post-PCI QFR and post-PCI ΔQFR (absolute increase of QFR) in de novo lesions of small coronary disease after drug-coated balloon (DCB).

OBJECTIVES

We sought to investigate the prognostic implications of post-PCI QFR and post-PCI ΔQFR in patients who received DCB only.

METHODS

Patients were divided according to the optimal cutoff value of the post-PCI QFR and the post-PCI ΔQFR. The primary outcome was major adverse cardiovascular events (MACE), including target vessel revascularization (TVR), cardiac death, and myocardial infarction (MI).

RESULTS

The optimal cutoff values of QFR and ΔQFR for the MACE rate were 0.86 and 0.57, respectively. There were 175 patients (61.2%) with a high QFR (≥ 0.86) and 113 patients (39.5%) with a high ΔQFR (≥ 0.57) after PCI. The MACE rate was significantly higher in patients with a low QFR compared to a high QFR (5.7% vs. 27.0%, hazard ratio [HR]: 3.632, 95% confidence interval [CI]: 1.872 to 7.044, P < 0.001). The MACE rate was higher in patients with a low ΔQFR increase compared to those with high ΔQFR (4.4% vs. 20.2%, HR: 4.700, 95%CI: 2.430 to 9.089, P = 0.001). In multivariable model, a low post-PCI QFR and a low post-PCI ΔQFR was independent predictor of MACE (adjusted HR: 4.071, 95%CI: 2.037 to 8.135, P = 0.001).

CONCLUSIONS

After DCB in de novo lesions of small coronary disease, both post-PCI QFR and ΔQFR showed similar prognostic implications in MACE.

Angiographic Findings and Post-Percutaneous Coronary Intervention Fractional Flow Reserve

Importance

The associations between angiographic findings and post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) and their clinical relevance according to residual functional disease burden have not been thoroughly investigated.

Objectives

To evaluate the association of angiographic and physiologic parameters according to residual functional disease burden after drug-eluting stent implantation.

Design, Setting, and Participants

This cohort study population was from the International Post-PCI FFR registry, which incorporated 4 registries from Korea, China, and Japan. Patients who underwent angiographically successful second-generation drug-eluting stent implantation and post-PCI FFR measurement were included in the analysis. The patients were divided into 3 groups according to the residual disease burden (post-PCI FFR ≤0.80 [residual ischemia], 0.81-0.86 [suboptimal], and >0.86 [optimal]). The data were collected from August 23, 2018, to June 11, 2019, and the current analysis was performed from January 11, 2022, to October 7, 2023.

Exposures

Angiographic parameters and post-PCI FFR.

Main Outcomes and Measures

The primary outcome was target vessel failure (TVF), defined as a composite of cardiac death, target vessel-related myocardial infarction, and target vessel revascularization (TVR) at 2 years.

Results

In this cohort of 2147 patients, the mean (SD) age was 64.3 (10.0) years, and 1644 patients (76.6%) were men. Based on the post-PCI physiologic status, 269 patients (12.5%) had residual ischemia, 551 (25.7%) had suboptimal results, and 1327 (61.8%) had optimal results. Angiographic parameters had poor correlations with post-PCI FFR (r < 0.20). Post-PCI FFR was isolated from all angiographic parameters in the unsupervised hierarchical cluster analysis. Post-PCI FFR was associated with the occurrence of TVF (adjusted hazard ratio [AHR] per post-PCI FFR 0.01 increase, 0.94 [95% CI, 0.92-0.97]; P < .001), but angiographic parameters were not. The residual ischemia group had a significantly higher rate of TVF than the suboptimal group (AHR, 1.75 [95% CI, 1.08-2.83]; P = .02) and the optimal group (AHR, 2.94 [95% CI, 1.82-4.73]; P < .001). The TVR in the residual ischemia group was predominantly associated with TVR in the nonstented segment (14 [53.8%]), unlike the other 2 groups (3 [10.0%] in the suboptimal group and 13 [30.2%] in the optimal group).

Conclusions and Relevance

In this cohort study of the International Post-PCI FFR registry, a low degree of associations were observed between angiographic and physiologic parameters after PCI. Post-PCI FFR, unlike angiographic parameters, was associated with clinical events and the distribution of clinical events. The current study supports the use of post-PCI FFR as a procedural quality metric and further prospective study is warranted.

Angiography-derived physiological assessment after percutaneous coronary intervention of chronic total occlusions

Scant data exploring potential suboptimal physiological results after angiographic successful percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) are available. Sixty cases of successful CTO-PCI were selected for this retrospective analysis. Post-CTO-PCI angiography-based fractional flow reserve was computed using the Murray-based fractional flow reserve (μFR) software. Vessel-specific μFR, residual trans-stent gradient (TSG) and corrected TSGstent were calculated. In physiological suboptimal results (μFR < 0.90), the virtual pullback pressure gradient (PPG) curves were analyzed to localize the main pressure drop-down and characterize the patterns of residual disease. The virtual pullback pressure gradient index (vPPGi) was then calculated to objectively characterize the predominant pattern of residual disease (diffuse vs focal). The physiological result was suboptimal in 28 cases (46.7%). The main pressure drop was localised proximal to the stent in 2 (7.1%), distal in 17 (60.7%) and intra-stent in 9 cases (32.2%). Intra-stent residual disease was diffuse in 7 cases and mixed in 2. Distal residual disease was characterised by a pure focal pattern in 12 cases, diffuse in 2 and mixed in 3. In the predominant diffuse phenotype (vPPGi < 0.65), we found a higher rate of TSG ≥ 0.04 (61.5% vs 20.0%, p = 0.025) and TSGstent ≥ 0.009 (46.2% vs 20.0%, p = 0.017) while in the dominant focal phenotype poor-quality distal vessel was constantly present. In our cohort, post-CTO-PCI suboptimal physiological result was frequent (46.7%). Predominant focal phenotype was constantly associated with poor-quality distal vessel, while in the predominant diffuse phenotype, the rate of TSG ≥ 0.04 and TSGstent ≥ 0.009 were significantly higher.

Prognostic Value of Poststenting Fractional Flow Reserve After Imaging-Guided Optimal Stenting

BACKGROUND

Prognostic value of poststenting fractional flow reserve (FFR) remains uncertain in patients undergoing an imaging-guided optimal stenting strategy.

OBJECTIVES

The authors evaluated the prognostic value of poststenting FFR according to the intracoronary imaging-guided lesion preparation, stent sizing, and postdilation (iPSP) strategy to optimize stent outcomes.

METHODS

Poststenting FFR assessment was performed in 1,108 lesions in 1,005 patients from the IRIS-FFR registry. The primary outcome was target vessel failure (TVF), a composite of cardiac death, target vessel myocardial infarction, and target vessel revascularization at 5 years.

RESULTS

At the index procedure, 326 lesions (29.4%) were treated using all 3 parts of the iPSP strategy. In the overall population, poststenting FFR was significantly associated with the risk of TVF at 5 years (per 0.01 increase of FFR, adjusted HR [aHR]: 0.94; 95% CI: 0.90-0.98; P = 0.004). Significant interaction was detected between poststenting FFR and the iPSP strategy on the risk of TVF at 5 years (P = 0.045 for interaction). In the iPSP group, poststenting FFR was not associated with the risk of TVF at 5 years (per 0.01 increase of FFR, aHR: 1.00; 95% CI: 0.96-1.05; P = 0.95), whereas a significant association between poststenting FFR and TVF at 5 years was observed in the no iPSP group (per 0.01 increase of FFR, aHR: 0.94; 95% CI: 0.90-0.99; P = 0.009).

CONCLUSIONS

Poststenting FFR showed a significant association with cardiac events. However, its prognostic value appeared to be limited after the application of an imaging-guided optimal stenting strategy.

Coronary Physiology Guidance vs Conventional Angiography for Optimization of Percutaneous Coronary Intervention: The AQVA-II Trial

BACKGROUND

The debate surrounding the efficacy of coronary physiological guidance compared with conventional angiography in achieving optimal post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) values persists.

OBJECTIVES

The primary aim of this study was to demonstrate the superiority of physiology-guided PCI, using either angiography or microcatheter-derived FFR, over conventional angiography-based PCI in complex high-risk indicated procedures (CHIPs). The secondary aim was to establish the noninferiority of angiography-derived FFR guidance compared with microcatheter-derived FFR guidance.

METHODS

Patients with obstructive coronary lesions and meeting CHIP criteria were randomized 2:1 to receive undergo physiology- or angiography-based PCI. Those assigned to the former were randomly allocated to angiography- or microcatheter-derived FFR guidance. CHIP criteria were long lesion (>28 mm), tandem lesions, severe calcifications, severe tortuosity, true bifurcation, in-stent restenosis, and left main stem disease. The primary outcome was invasive post-PCI FFR value. The optimal post-PCI FFR value was defined as >0.86.

RESULTS

A total of 305 patients (331 study vessels) were enrolled in the study (101 undergoing conventional angiography-based PCI and 204 physiology-based PCI). Optimal post-PCI FFR values were more frequent in the physiology-based PCI group compared with the conventional angiography-based PCI group (77% vs 54%; absolute difference 23%, relative difference 30%; P < 0.0001). The occurrence of the primary outcome did not differ between the 2 physiology-based PCI subgroups, demonstrating the noninferiority of angiography- vs microcatheter-derived FFR (P < 0.01).

CONCLUSIONS

In CHIP patients, procedural planning and guidance on the basis of physiology (through either angiography- or microcatheter-derived FFR) are superior to conventional angiography for achieving optimal post-PCI FFR values. (Physiology Optimized Versus Angio-Guided PCI [AQVA-II]; NCT05658952).

Preprocedural physiological assessment of coronary disease patterns to predict haemodynamic outcomes post-PCI

BACKGROUND

Even with intracoronary imaging-guided stent optimisation, suboptimal haemodynamic outcomes post-percutaneous coronary intervention (PCI) can be related to residual lesions in non-stented segments. Preprocedural assessment of pathophysiological coronary artery disease (CAD) patterns could help predict the physiological response to PCI.

AIMS

The aim of this study was to assess the relationship between preprocedural pathophysiological haemodynamic patterns and intracoronary imaging findings, as well as their association with physiological outcomes immediately post-PCI.

METHODS

Data from 206 patients with chronic coronary syndrome enrolled in the ASET-JAPAN study were analysed. Pathophysiological CAD patterns were characterised using Murray law-based quantitative flow ratio (μQFR)-derived indices acquired from pre-PCI angiograms. The diffuseness of CAD was defined by the pullback pressure gradient (PPG) index. Intracoronary imaging in stented segments after stent optimisation was also analysed.

RESULTS

In the multivariable analysis, diffuse disease - defined by the pre-PCI μQFR-PPG index - was an independent factor for predicting a post-PCI μQFR <0.91 (per 0.1 decrease of PPG index, odds ratio 1.57, 95% confidence interval: 1.07-2.34; p=0.022), whereas the stent expansion index (EI) was not associated with a suboptimal post-PCI μQFR. Among vessels with an EI ≥80% and post-PCI μQFR <0.91, 84.0% of those vessels had a diffuse pattern preprocedure. There was no significant difference in EI between vessels with diffuse disease and those with focal disease. The average plaque burden in the stented segment was significantly larger in vessels with a preprocedural diffuse CAD pattern.

CONCLUSIONS

A physiological diffuse pattern preprocedure was an independent factor in predicting unfavourable immediate haemodynamic outcomes post-PCI, even after stent optimisation using intracoronary imaging. Preprocedural assessment of CAD patterns could identify patients who are likely to exhibit superior immediate haemodynamic outcomes following PCI.