Long-term Outcomes After Real-World Fractional Flow Reserve Use
Long-term Outcomes After Real-World Fractional Flow Reserve Use
In this long-term outcome study after real-world use of FFR in the DES era, it was found that: (1) the deferral of stenting according to FFR was associated with favorable long-term outcomes; (2) the determinants of early and delayed events in deferred lesions were the presence of diabetes mellitus and FFR ≤0.8, respectively; and (3) angiographic lesion severity was not an independent predictor for clinical events during follow-up among deferred lesions.
Several studies proved the clinical benefit of an FFR-guided revascularization strategy. However, long-term comprehensive patient-level and lesion-level outcomes after real-world use of FFR are not yet clearly defined in the DES era. In our registry, which included all patients in whom FFR was measured in at least one de novo lesion located in a major epicardial vessel, 5-year MACE rate was 14.8% in all patients, and 5-year target-lesion related event rate in FFR-guided deferred lesions (FFR>0.8 and defer) was 6.5%. These results are consistent with previous studies which showed favorable outcomes for an FFR-guided revascularization strategy. In 2-year follow-up results of the FAME study, the rates of TLR and MI in FFR-guided deferred lesions were 3.2% and 0.2%, respectively. In the DEFER study, 5-year target vessel revascularization rate of deferred lesions with FFR ≥0.75 was 8.9%.
Residual stenosis after revascularization and the presence of coronary plaque are reported to be associated with increased risk of cardiovascular events. Moses et al reported favorable outcomes after DES implantation without physiologic assessment in patients with intermediate stenosis. Therefore, some operators might believe that stenting functionally insignificant lesions with DES can improve patient outcomes. In the DEFER study, performed in the bare-metal stent era, there was no difference in 5-year event-free survival rate between defer and revascularization for functionally insignificant lesions (FFR ≥0.75). In our study, there was no difference in long-term target-lesion related outcomes between deferred and stented lesions among lesions with FFR >0.8 and angiographic lesion severity was not an independent predictor for clinical events in deferred lesions. These results suggest that the lesson learned from the DEFER study still applies in the DES era.
It is well known that coronary events can occur at the site of angiographically or functionally insignificant stenoses. In our study, predictors of target-lesion related events among deferred lesions were the presence of diabetes for 1-year events and FFR ≤0.8 for delayed events. However, angiographic lesion severity was not an independent predictor for clinical events during follow-up among deferred lesions. This result is in agreement with the FAME II study and suggests that leaving the functionally significant stenosis, and not angiographically significant stenosis, is associated with higher risk of target-lesion related events during long-term follow-up. The different time interval from the FFR measurement and clinical event between the FAME II study and ours may be due to the difference in the degree of clinical and angiographic severity in deferred functionally significant stenosis. In our study, clinically indicated severe stenosis was treated without FFR measurement, reflective of real-world clinical practice.
The outcomes of medical treatment and revascularization may differ between Westerners and Asians due to the difference in body and vessel size, risk factor profile, and regional differences in medical practice patterns and health-care policies. However, our study revealed that the results of previous FFR studies can be applied to all patients with coronary artery disease, regardless of ethnicity.
Our study has several limitations. First, this is a non-randomized study and therefore cannot overcome all limitations inherent in a registry study. Second, plaque vulnerability was not assessed in our study. Third, the frequency of FFR non-compliance in our study was 19% and higher than previous studies (17% in a study by Legalery et al and 5% in a study by Muller et al). The main reason for this non-compliant strategy was frequent use of intravascular ultrasound (IVUS). Among 208 lesions with FFR >0.8 and stenting, a total of 82 lesions (39%) were stented due to the IVUS findings. Our study results again showed that an IVUS-guided strategy might result in more stent implantations without improvement in patient outcomes.
Discussion
In this long-term outcome study after real-world use of FFR in the DES era, it was found that: (1) the deferral of stenting according to FFR was associated with favorable long-term outcomes; (2) the determinants of early and delayed events in deferred lesions were the presence of diabetes mellitus and FFR ≤0.8, respectively; and (3) angiographic lesion severity was not an independent predictor for clinical events during follow-up among deferred lesions.
Several studies proved the clinical benefit of an FFR-guided revascularization strategy. However, long-term comprehensive patient-level and lesion-level outcomes after real-world use of FFR are not yet clearly defined in the DES era. In our registry, which included all patients in whom FFR was measured in at least one de novo lesion located in a major epicardial vessel, 5-year MACE rate was 14.8% in all patients, and 5-year target-lesion related event rate in FFR-guided deferred lesions (FFR>0.8 and defer) was 6.5%. These results are consistent with previous studies which showed favorable outcomes for an FFR-guided revascularization strategy. In 2-year follow-up results of the FAME study, the rates of TLR and MI in FFR-guided deferred lesions were 3.2% and 0.2%, respectively. In the DEFER study, 5-year target vessel revascularization rate of deferred lesions with FFR ≥0.75 was 8.9%.
Residual stenosis after revascularization and the presence of coronary plaque are reported to be associated with increased risk of cardiovascular events. Moses et al reported favorable outcomes after DES implantation without physiologic assessment in patients with intermediate stenosis. Therefore, some operators might believe that stenting functionally insignificant lesions with DES can improve patient outcomes. In the DEFER study, performed in the bare-metal stent era, there was no difference in 5-year event-free survival rate between defer and revascularization for functionally insignificant lesions (FFR ≥0.75). In our study, there was no difference in long-term target-lesion related outcomes between deferred and stented lesions among lesions with FFR >0.8 and angiographic lesion severity was not an independent predictor for clinical events in deferred lesions. These results suggest that the lesson learned from the DEFER study still applies in the DES era.
It is well known that coronary events can occur at the site of angiographically or functionally insignificant stenoses. In our study, predictors of target-lesion related events among deferred lesions were the presence of diabetes for 1-year events and FFR ≤0.8 for delayed events. However, angiographic lesion severity was not an independent predictor for clinical events during follow-up among deferred lesions. This result is in agreement with the FAME II study and suggests that leaving the functionally significant stenosis, and not angiographically significant stenosis, is associated with higher risk of target-lesion related events during long-term follow-up. The different time interval from the FFR measurement and clinical event between the FAME II study and ours may be due to the difference in the degree of clinical and angiographic severity in deferred functionally significant stenosis. In our study, clinically indicated severe stenosis was treated without FFR measurement, reflective of real-world clinical practice.
The outcomes of medical treatment and revascularization may differ between Westerners and Asians due to the difference in body and vessel size, risk factor profile, and regional differences in medical practice patterns and health-care policies. However, our study revealed that the results of previous FFR studies can be applied to all patients with coronary artery disease, regardless of ethnicity.
Study Limitations
Our study has several limitations. First, this is a non-randomized study and therefore cannot overcome all limitations inherent in a registry study. Second, plaque vulnerability was not assessed in our study. Third, the frequency of FFR non-compliance in our study was 19% and higher than previous studies (17% in a study by Legalery et al and 5% in a study by Muller et al). The main reason for this non-compliant strategy was frequent use of intravascular ultrasound (IVUS). Among 208 lesions with FFR >0.8 and stenting, a total of 82 lesions (39%) were stented due to the IVUS findings. Our study results again showed that an IVUS-guided strategy might result in more stent implantations without improvement in patient outcomes.
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