Kyung-Jin Kim

Clinical implications of three-vessel fractional flow reserve measurement in patients with coronary artery disease

AimsnThere are limited data on the clinical implications of total physiologic atherosclerotic burden assessed by invasive physiologic studies in patients with coronary artery disease. We investigated the prognostic implications of total physiologic atherosclerotic burden assessed by total sum of fractional flow reserve (FFR) in three vessels (3V-FFR).nnnMethods and resultsnA total of 1136 patients underwent FFR measurement in three vessels (3V FFR-FRIENDS study, NCT01621438). The patients were classified into high and low 3V-FFR groups according to the median value of 3V-FFR (2.72). The primary endpoint was major adverse cardiac events (MACE, a composite of cardiac death, myocardial infarction and ischaemia-driven revascularization) at 2u2009years. Mean angiographic percent diameter stenosis and FFR were 43.7u2009±u200919.3% and 0.90u2009±u20090.08, respectively. There was a negative correlation between 3V-FFR and estimated 2-year MACE rate (Pu2009<u20090.001). The patients in low 3V-FFR group showed a higher risk of 2-year MACE than those in the high 3V-FFR group [(7.1% vs. 3.8%, hazard ratio (HR) 2.205, 95% confidence interval (CI) 1.201-4.048, Pu2009=u20090.011]. The higher 2-year MACE rate was mainly driven by the higher rate of ischaemia-driven revascularization in the low 3V-FFR group (6.2% vs. 2.7%, HR 2.568, 95% CI 1.283-5.140, Pu2009=u20090.008). In a multivariable adjusted model, low 3V-FFR was an independent predictor of MACE (HR 2.031, 95% CI 1.078-3.830, Pu2009=u20090.029).nnnConclusionnPatients with high total physiologic atherosclerotic burden assessed by 3V-FFR showed higher risk of 2-year clinical events than those with low total physiologic atherosclerotic burden. The difference was mainly driven by ischaemia-driven revascularization for both functionally significant and insignificant lesions at baseline. Three-vessel FFR might be used as a prognostic indicator in patients with coronary artery disease.nnnClinical trial registrationn3V FFR-FRIENDS study (https://clinicaltrials.gov/ct2/show/NCT01621438, NCT01621438).

Percutaneous Coronary Intervention at Centers With and Without On-Site Surgical Backup: An Updated Meta-Analysis of 23 Studies.

Background— Emergency coronary artery bypass grafting for unsuccessful percutaneous coronary intervention (PCI) is now rare. We aimed to evaluate the current safety and outcomes of primary PCI and nonprimary PCI at centers with and without on-site surgical backup. Methods and Results— We performed an updated systematic review and meta-analysis by using mixed-effects models. We included 23 high-quality studies that compared clinical outcomes and complication rates of 1 101 123 patients after PCI at centers with or without on-site surgery. For primary PCI for ST-segment–elevation myocardial infarction (133 574 patients), all-cause mortality (without on-site surgery versus with on-site surgery: observed rates, 4.8% versus 7.2%; pooled odds ratio [OR], 0.99; 95% confidence interval, 0.91–1.07; P=0.729; I2=3.4%) or emergency coronary artery bypass grafting rates (observed rates, 1.5% versus 2.4%; pooled OR, 0.76; 95% confidence interval, 0.56–1.01; P=0.062; I2=42.5%) did not differ by presence of on-site surgery. For nonprimary PCI (967 549 patients), all-cause mortality (observed rates, 1.6% versus 2.1%; pooled OR, 1.15; 95% confidence interval, 0.94–1.41; P=0.172; I2=67.5%) and emergency coronary artery bypass grafting rates (observed rates, 0.5% versus 0.8%; pooled OR, 1.14; 95% confidence interval, 0.62–2.13; P=0.669; I2=81.7%) were not significantly different. PCI complication rates (cardiogenic shock, stroke, aortic dissection, tamponade, recurrent infarction) also did not differ by on-site surgical capability. Cumulative meta-analysis of nonprimary PCI showed a temporal decrease of the effect size (OR) for all-cause mortality after 2007. Conclusions— Clinical outcomes and complication rates of PCI at centers without on-site surgery did not differ from those with on-site surgery, for both primary and nonprimary PCI. Temporal trends indicated improving clinical outcomes in nonprimary PCI at centers without on-site surgery.

Clinical Outcomes According to Fractional Flow Reserve or Instantaneous Wave-Free Ratio in Deferred Lesions

OBJECTIVESnThe authors investigated 2-year clinical outcomes according to fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) values in deferred lesions.nnnBACKGROUNDnInvasive physiological indices such as FFR or iFR are used in clinical practice to select ischemia-causing stenosis and to guide the treatment strategy for patients with coronary artery disease.nnnMETHODSnFrom the 3V FFR-FRIENDS (3-Vessel Fractional Flow Reserve for the Assessment of Total Stenosis Burden and Its Clinical Impact in Patients With Coronary Artery Disease) study, 821 deferred lesions (n = 374) with both FFR and iFR available were included in this study. The primary outcome was major adverse cardiac events (MACE) (a composite of cardiac death, myocardial infarction, and ischemia-driven revascularization) at 2 years. The lesions were classified according to FFR and iFR cutpoints into concordant normal (Group 1: FFR >0.80 and iFR >0.89), high FFR and low iFR (Group 2: FFR >0.80 and iFRxa0≤0.89), low FFR and high iFR (Group 3: FFRxa0≤0.80 and iFR >0.89), and concordant abnormal (Group 4: FFRxa0≤0.80 and iFRxa0≤0.89).nnnRESULTSnDeferred lesions with low FFR (≤0.80) or low iFR (≤0.89) showed significantly higher rates of 2-year MACE, compared with high FFR (>0.80) or high iFR (>0.89), respectively (7.2% in low FFR vs. 2.4% in high FFR; pxa0< 0.001; 8.1% in low iFR vs. 2.4% in high iFR; pxa0< 0.001). Both FFR and iFR showed significant association with occurrence of MACE as continuous values (hazard ratio [HR] of FFR: 0.570, 95% confidence interval [CI]: 0.337 to 0.963; pxa0< 0.001; HR of iFR: 0.350, 95% CI: 0.217 to 0.567; pxa0< 0.001). When comparing the discriminant ability between FFR and iFR, the c-index was comparable between FFR and iFR (c-index 0.677 vs. 0.685; pxa0= 0.857). Among 4 groups classified according to FFR and iFR levels, only Group 4 with concordant abnormal results showed significantly higher risk of MACE, compared with group 1 (HR: 7.708, 95% CI: 2.621 to 22.667; pxa0< 0.001).nnnCONCLUSIONSnBoth FFR and iFR showed significant association with future risk of MACE in deferred lesions. The discordant results between FFR and iFR were not associated with the increased risk of MACE. The risk of MACE wasxa0significantly increased only in lesions with abnormal results of both FFR and iFR.

Identification of High-Risk Plaques Destined to Cause Acute Coronary Syndrome Using Coronary Computed Tomographic Angiography and Computational Fluid Dynamics

OBJECTIVESnThe authors investigated the utility of noninvasive hemodynamic assessment in the identification of high-risk plaques that caused subsequent acute coronary syndrome (ACS).nnnBACKGROUNDnACS is a critical event that impacts the prognosis of patients with coronary artery disease. However, the role of hemodynamic factors in the development of ACS is not well-known.nnnMETHODSnSeventy-two patients with clearly documented ACS and available coronary computed tomographic angiography (CTA) acquired between 1 month and 2 years before the development of ACS were included. In 66 culprit and 150 nonculprit lesions as a case-control design, the presence of adverse plaque characteristics (APC) was assessed and hemodynamic parameters (fractional flow reserve derived by coronary computed tomographic angiography [FFRCT], change in FFRCT across the lesion [△FFRCT], wall shear stress [WSS], and axial plaque stress) were analyzed using computational fluid dynamics. The best cut-off values for FFRCT, △FFRCT, WSS, and axial plaque stress were used to define the presence of adverse hemodynamic characteristics (AHC). The incremental discriminant and reclassification abilities for ACS prediction were compared among 3 models (model 1: percent diameter stenosis [%DS] and lesion length, model 2: model 1xa0+ APC, and model 3: model 2xa0+ AHC).nnnRESULTSnThe culprit lesions showed higher %DS (55.5 ± 15.4% vs. 43.1 ± 15.0%; pxa0< 0.001) and higher prevalence of APC (80.3% vs. 42.0%; pxa0< 0.001) than nonculprit lesions. Regarding hemodynamic parameters, culprit lesions showed lower FFRCT and higher △FFRCT, WSS, and axial plaque stress than nonculprit lesions (all p valuesxa0<0.01). Among the 3 models, model 3, which included hemodynamic parameters, showed the highest c-index, and better discrimination (concordance statistic [c-index] 0.789 vs. 0.747; pxa0= 0.014) and reclassification abilities (category-free net reclassification index 0.287; pxa0= 0.047; relative integrated discrimination improvement 0.368; pxa0< 0.001) than model 2. Lesions with both APC and AHC showed significantly higher risk of the culprit for subsequent ACS than those with no APC/AHC (hazard ratio: 11.75; 95% confidence interval: 2.85 to 48.51; pxa0= 0.001) and with either APC or AHC (hazard ratio: 3.22; 95% confidence interval: 1.86 to 5.55; pxa0< 0.001).nnnCONCLUSIONSnNoninvasive hemodynamic assessment enhanced the identification of high-risk plaques that subsequently caused ACS. The integration of noninvasive hemodynamic assessments may improve the identification of culprit lesions for future ACS. (Exploring the Mechanism of Plaque Rupture in Acute Coronary Syndrome Using Coronary CT Angiography and Computational Fluid Dynamic [EMERALD]; NCT02374775).

Discrepancy between fractional flow reserve and instantaneous wave-free ratio: Clinical and angiographic characteristics

BACKGROUNDnThe invasive physiologic index such as fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) is used in clinical practice to identify ischemia-causing stenosis and to guide treatment strategy. We investigated clinical and angiographic characteristics of lesions with discrepancy between FFR and iFR.nnnMETHODSnFrom the 3V FFR-FRIENDS study, 975 vessels (393 patients) with available pre-intervention FFR and iFR were included in this study. The vessels were classified according to FFR and iFR into: concordant normal (Group 1 [n=724]: FFR>0.80 and iFR≥0.90); high FFR and low iFR (Group 2 [n=33]: FFR>0.80 and iFR<0.90); low FFR and high iFR (Group 3 [n=82]: FFR≤0.80 and iFR≥0.90); and concordant abnormal (Group 4 [n=136]: FFR≤0.80 and iFR<0.90).nnnRESULTSnAngiographic stenosis severity assessed by percent diameter stenosis, minimum lumen diameter and lesion length was increased from Group 1 to Group 4 (all p<0.001). SYNTAX score increased and FFR decreased proportionally from Group 1 to Group 4 (all p<0.001). In multivariable GEE model, female, diabetes mellitus, smaller reference vessel diameter, and higher %DS were significantly associated with low iFR among high FFR groups (Group 2 discordance). Conversely, males, absence of diabetes mellitus and lower %DS were significantly associated with high iFR among low FFR groups (Group 3 discordance).nnnCONCLUSIONSnFour groups classified according to FFR and iFR were different in clinical and angiographic characteristics, SYNTAX score, and predictors of discordance. The lesions with discordant FFR and iFR may need to be interpreted as a different clinical entity.

Percutaneous Coronary Intervention at Centers With and Without On-Site Surgical BackupClinical Perspective: An Updated Meta-Analysis of 23 Studies

Background— Emergency coronary artery bypass grafting for unsuccessful percutaneous coronary intervention (PCI) is now rare. We aimed to evaluate the current safety and outcomes of primary PCI and nonprimary PCI at centers with and without on-site surgical backup. Methods and Results— We performed an updated systematic review and meta-analysis by using mixed-effects models. We included 23 high-quality studies that compared clinical outcomes and complication rates of 1 101 123 patients after PCI at centers with or without on-site surgery. For primary PCI for ST-segment–elevation myocardial infarction (133 574 patients), all-cause mortality (without on-site surgery versus with on-site surgery: observed rates, 4.8% versus 7.2%; pooled odds ratio [OR], 0.99; 95% confidence interval, 0.91–1.07; P=0.729; I2=3.4%) or emergency coronary artery bypass grafting rates (observed rates, 1.5% versus 2.4%; pooled OR, 0.76; 95% confidence interval, 0.56–1.01; P=0.062; I2=42.5%) did not differ by presence of on-site surgery. For nonprimary PCI (967 549 patients), all-cause mortality (observed rates, 1.6% versus 2.1%; pooled OR, 1.15; 95% confidence interval, 0.94–1.41; P=0.172; I2=67.5%) and emergency coronary artery bypass grafting rates (observed rates, 0.5% versus 0.8%; pooled OR, 1.14; 95% confidence interval, 0.62–2.13; P=0.669; I2=81.7%) were not significantly different. PCI complication rates (cardiogenic shock, stroke, aortic dissection, tamponade, recurrent infarction) also did not differ by on-site surgical capability. Cumulative meta-analysis of nonprimary PCI showed a temporal decrease of the effect size (OR) for all-cause mortality after 2007. Conclusions— Clinical outcomes and complication rates of PCI at centers without on-site surgery did not differ from those with on-site surgery, for both primary and nonprimary PCI. Temporal trends indicated improving clinical outcomes in nonprimary PCI at centers without on-site surgery.

Percutaneous Coronary Intervention at Centers With and Without On-Site Surgical BackupClinical Perspective

Background— Emergency coronary artery bypass grafting for unsuccessful percutaneous coronary intervention (PCI) is now rare. We aimed to evaluate the current safety and outcomes of primary PCI and nonprimary PCI at centers with and without on-site surgical backup. Methods and Results— We performed an updated systematic review and meta-analysis by using mixed-effects models. We included 23 high-quality studies that compared clinical outcomes and complication rates of 1 101 123 patients after PCI at centers with or without on-site surgery. For primary PCI for ST-segment–elevation myocardial infarction (133 574 patients), all-cause mortality (without on-site surgery versus with on-site surgery: observed rates, 4.8% versus 7.2%; pooled odds ratio [OR], 0.99; 95% confidence interval, 0.91–1.07; P=0.729; I2=3.4%) or emergency coronary artery bypass grafting rates (observed rates, 1.5% versus 2.4%; pooled OR, 0.76; 95% confidence interval, 0.56–1.01; P=0.062; I2=42.5%) did not differ by presence of on-site surgery. For nonprimary PCI (967 549 patients), all-cause mortality (observed rates, 1.6% versus 2.1%; pooled OR, 1.15; 95% confidence interval, 0.94–1.41; P=0.172; I2=67.5%) and emergency coronary artery bypass grafting rates (observed rates, 0.5% versus 0.8%; pooled OR, 1.14; 95% confidence interval, 0.62–2.13; P=0.669; I2=81.7%) were not significantly different. PCI complication rates (cardiogenic shock, stroke, aortic dissection, tamponade, recurrent infarction) also did not differ by on-site surgical capability. Cumulative meta-analysis of nonprimary PCI showed a temporal decrease of the effect size (OR) for all-cause mortality after 2007. Conclusions— Clinical outcomes and complication rates of PCI at centers without on-site surgery did not differ from those with on-site surgery, for both primary and nonprimary PCI. Temporal trends indicated improving clinical outcomes in nonprimary PCI at centers without on-site surgery.