Randomized Comparison of FFR-Guided and Angiography-Guided Provisional Stenting of True Coronary Bifurcation Lesions: The DKCRUSH-VI Trial (Double Kissing Crush Versus Provisional Stenting Technique for Treatment of Coronary Bifurcation Lesions VI)

ObjectivesThis study sought to compare the outcomes of fractional flow reserve (FFR)–guided and angiography (Angio)–guided provisional side-branch (SB) stenting for true coronary bifurcation lesions.BackgroundAngio-guided provisional SB stenting after stenting of the main vessel provides favorable outcomes for the majority of coronary bifurcation lesions. Whether an FFR-guided provisional stenting approach is superior has not been studied.MethodsA total of 320 patients with single Medina 1,1,1 and 0,1,1 coronary bifurcation lesions undergoing stenting with a provisional SB approach were randomly assigned 1:1 to Angio-guided and FFR-guided groups. SB stenting was performed for Thrombolysis In Myocardial Infarction flow grade <3, ostial SB stenosis >70%, or greater than type A dissection after main vessel stenting in the Angio-guided group and for SB-FFR <0.80 in the FFR-guided group. The primary endpoint was the 1-year composite rate of major adverse cardiac events (cardiac death, myocardial infarction, and clinically driven target vessel revascularization).ResultsComparing the Angio-guided and FFR-guided groups, treatment of the SB (balloon or stenting) was performed in 63.1% and 56.3% of lesions respectively (p = 0.07); stenting of the SB was attempted in 38.1% and 25.9%, respectively (p = 0.01); and, when attempted, stenting was successful in 83.6% and 73.3% of SBs, respectively (p = 0.01). The 1-year composite major adverse cardiac event rate was 18.1% in both groups (hazard ratio: 0.91, 95% confidence interval: 0.48 to 1.88; p = 1.00). The 1-year target vessel revascularization and stent thrombosis rates were 6.9% and 5.6% (p = 0.82) and 1.3% and 0.6% (p = 0.56) in the Angio-guided and FFR-guided groups, respectively.ConclusionsIn this multicenter, randomized trial, angiographic and FFR guidance of provisional SB stenting of true coronary bifurcation lesions provided similar 1-year clinical outcomes. (Randomized Study on DK Crush Technique Versus Provisional Stenting Technique for Coronary Artery Bifurcation Lesions; ChiCTR-TRC-07000015)     

The Impact of Downstream Coronary Stenosis on Fractional Flow Reserve Assessment of Intermediate Left Main Coronary Artery Disease: Human Validation

ObjectivesThe aim of this study was to determine the impact of downstream coronary stenosis in the left anterior descending coronary artery (LAD) or left circumflex coronary artery (LCx) on the assessment of fractional flow reserve (FFR) across an intermediate left main coronary artery (LMCA) stenosis in humans with the pressure wire positioned in the nondiseased downstream vessel.BackgroundAccurate assessment of intermediate LMCA disease is critical for guiding decisions regarding revascularization. In theory, FFR across an intermediate LMCA stenosis will be affected by downstream disease, even if the pressure wire is positioned in the nondiseased downstream vessel.MethodsAfter percutaneous coronary intervention of the LAD, LCx, or both, an intermediate LMCA stenosis was created with a deflated balloon catheter. FFR was measured in the LAD and LCx coronary arteries before and after creation of downstream stenosis by inflating an angioplasty balloon within the newly placed stent. The true FFR (FFR_true) of the LMCA, measured in the nondiseased downstream vessel in the absence of stenosis in the other vessel, was compared with the apparent FFR (FFR_app) measured in the presence of stenosis.ResultsIn 25 patients, 91 pairs of measurements were made, 71 with LAD stenosis and 20 with LCx stenosis. FFR_true of the LMCA was significantly lower than FFR_app (0.81 ± 0.08 vs. 0.83 ± 0.08, p < 0.001), although the numerical difference was small. This difference correlated with the severity of the downstream disease (r = 0.35, p < 0.001). In all cases in which FFR_app was >0.85, FFR_true was >0.80.ConclusionsIn most cases, downstream disease does not have a clinically significant impact on the assessment of FFR across an intermediate LMCA stenosis with the pressure wire positioned in the nondiseased vessel.     

Intravascular Ultrasound-Derived Minimal Lumen Area Criteria for Functionally Significant Left Main Coronary Artery Stenosis

ObjectivesThis study sought to evaluate the intravascular ultrasound (IVUS) minimal lumen area (MLA) for functionally significant left main coronary artery (LMCA) stenosis using fractional flow reserve (FFR) as the standard.BackgroundThe evaluation of significant LMCA stenosis remains challenging.MethodsWe identified 112 patients with isolated ostial and shaft intermediate LMCA stenosis (angiographic diameter stenosis of 30% to 80%) who underwent IVUS and FFR measurement.ResultsThe FFR was ≤0.80 in 66 LMCA lesions (59%); these exhibited smaller reference vessels, smaller minimal lumen diameter, greater diameter of stenosis, longer lesion length, smaller MLA, larger plaque burden, and more frequent plaque rupture. The independent factors of an FFR of ≤0.80 were plaque rupture (odds ratio [OR]: 4.47; 95% Confidence Interval (CI): 1.35 to 14.8; p = 0.014); body mass index (OR: 1.19; 95% CI: 1.00 to 1.41; p = 0.05), age (OR: 0.95; 95% CI: 0.90 to 1.00; p = 0.031), and IVUS MLA (OR: 0.37; 95% CI: 0.25 to 0.56; p < 0.001). The optimal IVUS MLA cutoff value for an FFR of ≤0.80 was 4.5 mm² (77% sensitivity, 82% specificity, 84% positive predictive value, 75% negative predictive value, area under the curve: 0.83, 95% CI: 0.76 to 0.96; p < 0.001) overall and 4.1 to 4.5 mm² in various subgroups. Adjustment for the body surface area, body mass index, and left ventricular mass did not improve the diagnostic accuracy of the IVUS MLA.ConclusionsIn patients with isolated ostial and shaft intermediate LMCA stenosis, an IVUS-derived MLA of ≤4.5 mm² is a useful index of an FFR of ≤0.80.     

Combining Baseline Distal-to-Aortic Pressure Ratio and Fractional Flow Reserve in the Assessment of Coronary Stenosis Severity

ObjectivesThis study sought to understand the physiological basis of baseline distal-to-aortic pressure ratio (Pd/Pa) and fractional flow reserve (FFR) agreement and discordance, using coronary flow reserve (CFR), stenosis resistance, and microcirculatory resistance measurements, and form there, to investigate the potential value of combining Pd/Pa with FFR in the diagnostic rationale.BackgroundPd/Pa is always available before FFR assessment, and emerging data supports the notion that baseline indices can determine the ischemic potential of coronary stenosis in selected subsets.MethodsA total of 467 stenosed vessels from 363 patients were investigated with pressure and flow sensors during baseline and hyperemia: 168 vessels (135 patients) with thermodilution-derived flow, and 299 vessels (228 patients) with Doppler-derived flow.ResultsPd/Pa correlated more strongly with CFR than FFR (ρ difference = 0.129; p for ρ comparison <0.001). Although Pd/Pa and FFR were closely correlated (ρ = 0.798; 95% confidence interval: 0.767 to 0.828), categorical discordance was observed in 19.3% of total vessels. Such discordance was associated with the patients’ clinical profile and was characterized by contrastive changes in stenosis resistance, microcirculatory resistance, and the underlying CFR. Notably, all stenosis with Pd/Pa ≤0.83 (n = 74, 15.8%) progressed to FFR ≤0.80, and although no Pd/Pa cutoff was able to exclude the development of FFR ≤0.80 in the high end of values, only 15 (10.1%) vessels with Pd/Pa ≥0.96 (n = 149, 31.9%) developed FFR ≤0.80, from which none had definite ischemia, as defined by CFR ≤1.74.ConclusionsCombining baseline Pd/Pa with FFR seems to provide a more comprehensive physiological examination of stenosed coronary arteries and a closer pressure-based appraisal of the flow reserve of the downstream myocardial bed.     

Fractional Flow Reserve and Coronary Bifurcation Anatomy: A Novel Quantitative Model to Assess and Report the Stenosis Severity of Bifurcation Lesions

ObjectivesThe aim of this study was to develop a new model for assessment of stenosis severity in a bifurcation lesion including its core. The diagnostic performance of this model, powered by 3-dimensional quantitative coronary angiography to predict the functional significance of obstructive bifurcation stenoses, was evaluated using fractional flow reserve (FFR) as the reference standard.BackgroundDevelopment of advanced quantitative models might help to establish a relationship between bifurcation anatomy and FFR.MethodsPatients who had undergone coronary angiography and interventions in 5 European cardiology centers were randomly selected and analyzed. Different bifurcation fractal laws, including Murray, Finet, and HK laws, were implemented in the bifurcation model, resulting in different degrees of stenosis severity.ResultsA total of 78 bifurcation lesions in 73 patients were analyzed. In 51 (65%) bifurcations, FFR was measured in the main vessel. A total of 34 (43.6%) interrogated vessels had an FFR ≤0.80. Correlation between FFR and diameter stenosis was poor by conventional straight analysis (ρ = −0.23, p < 0.001) but significantly improved by bifurcation analyses: the highest by the HK law (ρ = −0.50, p < 0.001), followed by the Finet law (ρ = −0.49, p < 0.001), and the Murray law (ρ = −0.41, p < 0.001). The area under the receiver-operating characteristics curve for predicting FFR ≤0.80 was significantly higher by bifurcation analysis compared with straight analysis: 0.72 (95% confidence interval: 0.61 to 0.82) versus 0.60 (95% confidence interval: 0.49 to 0.71; p = 0.001). Applying a threshold of ≥50% diameter stenosis, as assessed by the bifurcation model, to predict FFR ≤0.80 resulted in 23 true positives, 27 true negatives, 17 false positives, and 11 false negatives.ConclusionsThe new bifurcation model provides a comprehensive assessment of bifurcation anatomy. Compared with straight analysis, identification of lesions with preserved FFR values in obstructive bifurcation stenoses was improved. Nevertheless, accuracy was limited by using solely anatomical parameters.     

Repeatability of Fractional Flow Reserve Despite Variations in Systemic and Coronary Hemodynamics

ObjectivesThis study classified and quantified the variation in fractional flow reserve (FFR) due to fluctuations in systemic and coronary hemodynamics during intravenous adenosine infusion.BackgroundAlthough FFR has become a key invasive tool to guide treatment, questions remain regarding its repeatability and stability during intravenous adenosine infusion because of systemic effects that can alter driving pressure and heart rate.MethodsWe reanalyzed data from the VERIFY (VERification of Instantaneous Wave-Free Ratio and Fractional Flow Reserve for the Assessment of Coronary Artery Stenosis Severity in EverydaY Practice) study, which enrolled consecutive patients who were infused with intravenous adenosine at 140 μg/kg/min and measured FFR twice. Raw phasic pressure tracings from the aorta (Pa) and distal coronary artery (Pd) were transformed into moving averages of Pd/Pa. Visual analysis grouped Pd/Pa curves into patterns of similar response. Quantitative analysis of the Pd/Pa curves identified the “smart minimum” FFR using a novel algorithm, which was compared with human core laboratory analysis.ResultsA total of 190 complete pairs came from 206 patients after exclusions. Visual analysis revealed 3 Pd/Pa patterns: “classic” (sigmoid) in 57%, “humped” (sigmoid with superimposed bumps of varying height) in 39%, and “unusual” (no pattern) in 4%. The Pd/Pa pattern repeated itself in 67% of patient pairs. Despite variability of Pd/Pa during the hyperemic period, the “smart minimum” FFR demonstrated excellent repeatability (bias −0.001, SD 0.018, paired p = 0.93, r² = 98.2%, coefficient of variation = 2.5%). Our algorithm produced FFR values not significantly different from human core laboratory analysis (paired p = 0.43 vs. VERIFY; p = 0.34 vs. RESOLVE).ConclusionsIntravenous adenosine produced 3 general patterns of Pd/Pa response, with associated variability in aortic and coronary pressure and heart rate during the hyperemic period. Nevertheless, FFR – when chosen appropriately – proved to be a highly reproducible value. Therefore, operators can confidently select the “smart minimum” FFR for patient care. Our results suggest that this selection process can be automated, yet comparable to human core laboratory analysis.     

Diagnostic and Prognostic Implications of Coronary Flow Capacity: A Comprehensive Cross-Modality Physiological Concept in Ischemic Heart Disease

ObjectivesThe purpose of this study is to evaluate whether coronary flow capacity (CFC) improves discrimination of patients at risk for major adverse cardiac events (MACE) compared with coronary flow reserve (CFR) alone, and to study the diagnostic and prognostic implications of CFC in relation to contemporary diagnostic tests for ischemic heart disease (IHD), including fractional flow reserve (FFR).BackgroundAlthough IHD results from a combination of focal obstructive, diffuse, and microcirculatory involvement of the coronary circulation, its diagnosis remains focused on focal obstructive causes. CFC comprehensively documents flow impairment in IHD, regardless of its origin, by interpreting CFR in relation to maximal flow (hyperemic average peak flow velocity [hAPV]), and overcomes the limitations of using CFR alone. This is governed by the understanding that ischemia occurs in vascular beds with substantially reduced hAPV and CFR, whereas ischemia is unlikely when hAPV or CFR is high.MethodsIntracoronary pressure and flow were measured in 299 vessels (228 patients), where revascularization was deferred in 154. Vessels were stratified as having normal, mildly reduced, moderately reduced, or severely reduced CFC using CFR thresholds derived from published data and corresponding hAPV percentiles. The occurrence of MACE after deferral of revascularization was recorded during 11.9 years of follow-up (quartile 1: 10.0 years, quartile 3: 13.4 years).ResultsCombining CFR and hAPV improved the prediction of MACE over CFR alone (p = 0.01). After stratification in CFC, MACE rates throughout follow-up were strongly associated with advancing impairment of CFC (p = 0.002). After multivariate adjustment, mildly and moderately reduced CFC were associated with a 2.1-fold (95% confidence interval: 1.1 to 4.0; p = 0.017), and 7.1-fold (95% confidence interval: 2.9 to 17.1; p < 0.001) increase in MACE hazard, respectively, compared with normal CFC. Severely reduced CFC was identified by FFR ≤0.80 in 90% of cases, although ≥40% of vessels with normal or mildly reduced CFC still had an FFR ≤0.80.ConclusionsCFC provides a cross-modality platform for the diagnosis and risk-stratification of IHD and enriches the interpretation of contemporary diagnostic tests in IHD.     

Long-Term Clinical Outcomes of Final Kissing Ballooning in Coronary Bifurcation Lesions Treated With the 1-Stent Technique: Results From the COBIS II Registry (Korean Coronary Bifurcation Stenting Registry)

ObjectivesThis study investigated the impact of final kissing ballooning (FKB) after main vessel (MV) stenting on outcomes in patients with coronary bifurcation lesions after application of the 1-stent technique.BackgroundAlthough FKB has been established as the standard method for bifurcation lesions treated with a 2-stent strategy, its efficacy in a 1-stent approach is highly controversial.MethodsThis study enrolled 1,901 patients with a bifurcation lesion with a side branch diameter ≥2.3 mm, treated solely with the 1-stent technique using a drug-eluting stent from 18 centers in Korea between January 1, 2003 and December 31, 2009. The primary outcome was major adverse cardiac events (MACE)—cardiac death, myocardial infarction, or target lesion revascularization. Propensity score-matching analysis was also performed.ResultsFKB was performed in 620 patients and the post minimal lumen diameter of the MV and side branch was larger in the FKB group than in the non-FKB group. During follow-up (median 36 months), the incidence of MACE (adjusted hazard ratio [HR]: 0.68, 95% confidence interval [CI]: 0.46 to 0.99; p = 0.048) was lower in the FKB group than the non-FKB group. After propensity score matching (545 pairs), the FKB group had a lower incidence of MACE (adjusted HR: 0.50, 95% CI: 0.30 to 0.85; p = 0.01), and target lesion revascularization in the MV (adjusted HR: 0.51, 95% CI: 0.28 to 0.93; p = 0.03) and both vessels (adjusted HR: 0.47, 95% CI: 0.25 to 0.90; p = 0.02) than in the non-FKB group.ConclusionsIn coronary bifurcation lesions, we demonstrated that the 1-stent technique with FKB was associated with a favorable long-term clinical outcome, mainly driven by the reduction of target lesion revascularization in the MV or both vessels as a result of an increase in minimal lumen diameter. (Korean Coronary Bifurcation Stenting Registry II [COBIS II]: NCT01642992)     

Prospective Assessment of the Diagnostic Accuracy of Instantaneous Wave-Free Ratio to Assess Coronary Stenosis Relevance: Results of ADVISE II International,Multicenter Study (ADenosine Vasodilator Independent Stenosis Evaluation II)

ObjectivesThe purpose of this study was to assess the diagnostic accuracy of the instantaneous wave-free ratio (iFR) to characterize, outside of a pre-specified range of values, stenosis severity, as defined by fractional flow reserve (FFR) ≤0.80, in a prospective, independent, controlled, core laboratory–based environment.BackgroundStudies with methodological heterogeneity have reported some discrepancies in the classification agreement between iFR and FFR. The ADVISE II (ADenosine Vasodilator Independent Stenosis Evaluation II) study was designed to overcome limitations of previous iFR versus FFR comparisons.MethodsA total of 919 intermediate coronary stenoses were investigated during baseline and hyperemia. From these, 690 pressure recordings (n = 598 patients) met core laboratory physiology criteria and are included in this report.ResultsThe pre-specified iFR cut-off of 0.89 was optimal for the study and correctly classified 82.5% of the stenoses, with a sensitivity of 73.0% and specificity of 87.8% (C statistic: 0.90 [95% confidence interval (CI): 0.88 to 0.92, p < 0.001]). The proportion of stenoses properly classified by iFR outside of the pre-specified treatment (≤0.85) and deferral (≥0.94) values was 91.6% (95% CI: 88.8% to 93.9%). When combined with FFR use within these cut-offs, the percent of stenoses properly classified by such a pre-specified hybrid iFR-FFR approach was 94.2% (95% CI: 92.2% to 95.8%). The hybrid iFR-FFR approach obviated vasodilators from 65.1% (95% CI: 61.1% to 68.9%) of patients and 69.1% (95% CI: 65.5% to 72.6%) of stenoses.ConclusionsThe ADVISE II study supports, on the basis rigorous methodology, the diagnostic value of iFR in establishing the functional significance of coronary stenoses, and highlights its complementariness with FFR when used in a hybrid iFR-FFR approach. (ADenosine Vasodilator Independent Stenosis Evaluation II–ADVISE II; NCT01740895)     

Long-Term Survival Benefit of Revascularization Compared With Medical Therapy in Patients With Coronary Chronic Total Occlusion and Well-Developed Collateral Circulation

ObjectivesThe purpose of this study was to compare the long-term clinical outcomes of patients with chronic total occlusion (CTO) and well-developed collateral circulation treated with revascularization versus medical therapy.BackgroundLittle is known about the clinical outcomes and optimal treatment strategies of CTO with well-developed collateral circulation.MethodsWe screened 2,024 consecutive patients with at least 1 CTO detected on coronary angiogram. Of these, we analyzed data from 738 patients with Rentrop 3 grade collateral circulation who were treated with medical therapy alone (n = 236), coronary artery bypass grafting (n = 170) or percutaneous coronary intervention (n = 332; 80.1% successful). Patients who underwent revascularization and medical therapy (revascularization group, n = 502) were compared with those who underwent medical therapy alone (medication group, n = 236) in terms of cardiac death and major adverse cardiac events (MACE), defined as the composite of cardiac death, myocardial infarction, and repeat revascularization.ResultsDuring a median follow-up duration of 42 months, multivariate analysis revealed a significantly lower incidence of cardiac death (hazard ratio [HR]: 0.29; 95% confidence interval [CI]: 0.15 to 0.58; p < 0.01) and MACE (HR: 0.32; 95% CI: 0.21 to 0.49; p < 0.01) in the revascularization group compared with the medication group. After propensity score matching, the incidence of cardiac death (HR: 0.27; 95% CI: 0.09 to 0.80; p = 0.02) and MACE (HR: 0.44; 95% CI: 0.23 to 0.82; p = 0.01) were still significantly lower in the revascularization group than in the medication group.ConclusionsIn patients with coronary CTO and well-developed collateral circulation, aggressive revascularization may reduce the risk of cardiac mortality and MACE.     

Comparative Analysis of Sequential Proximal Optimizing Technique Versus Kissing Balloon Inflation Technique in Provisional Bifurcation Stenting: Fractal Coronary Bifurcation Bench Test

ObjectivesThis study used a fractal bifurcation bench model to compare 6 optimization sequences for coronary bifurcation provisional stenting, including 1 novel sequence without kissing balloon inflation (KBI), comprising initial proximal optimizing technique (POT) + side-branch inflation (SBI) + final POT, called “re-POT.”BackgroundIn provisional bifurcation stenting, KBI fails to improve the rate of major adverse cardiac events. Proximal geometric deformation increases the rate of in-stent restenosis and target lesion revascularization.MethodsA bifurcation bench model was used to compare KBI alone, KBI after POT, KBI with asymmetric inflation pressure after POT, and 2 sequences without KBI: initial POT plus SBI, and initial POT plus SBI with final POT (called “re-POT”). For each protocol, 5 stents were tested using 2 different drug-eluting stent designs: that is, a total of 60 tests.ResultsCompared with the classic KBI-only sequence and those associating POT with modified KBI, the re-POT sequence gave significantly (p < 0.05) better geometric results: it reduced SB ostium stent-strut obstruction from 23.2 ± 6.0% to 5.6 ± 8.3%, provided perfect proximal stent apposition with almost perfect circularity (ellipticity index reduced from 1.23 ± 0.02 to 1.04 ± 0.01), reduced proximal area overstretch from 24.2 ± 7.6% to 8.0 ± 0.4%, and reduced global strut malapposition from 40 ± 6.2% to 2.6 ± 1.4%.ConclusionsIn comparison with 5 other techniques, the re-POT sequence significantly optimized the final result of provisional coronary bifurcation stenting, maintaining circular geometry while significantly reducing SB ostium strut obstruction and global strut malapposition. These experimental findings confirm that provisional stenting may be optimized more effectively without KBI using re-POT.     

Outcomes of Spot Stenting Versus Long Stenting After Intentional Subintimal Approach for Long Chronic Total Occlusions of the Femoropopliteal Artery

ObjectivesThis study sought to compare the outcomes of spot stenting versus long stenting after intentional subintimal approach for long femoropopliteal chronic total occlusions (CTO).BackgroundThe optimal stenting strategy following the subintimal recanalization of long femoropopliteal chronic total occlusions has not been investigated.MethodsA total of 196 limbs in 163 patients, implanted with bare nitinol stents after subintimal approach in long femoropopliteal occlusions (lesion length 25 ± 8 cm), were retrospectively analyzed. The primary patency was compared between spot stenting (n = 129) and long stenting (n = 67).ResultsBaseline characteristics and immediate procedural results were similar between groups. Adjusted-primary patency (47% vs. 77%, p < 0.001) and adjusted-freedom from target lesion revascularization (52% vs. 84%, p < 0.001) at 2 years were significantly lower in the long stenting group than in the spot stenting group. The incidence of stent fracture, fracture type, and restenosis pattern did not differ between groups. Long stenting was an independent predictor of restenosis (hazard ratio [HR]: 2.0) along with other risk factors such as nonuse of clopidogrel (HR: 3.3) or cilostazol (HR: 2.2), small stent diameter (HR: 0.6), poor run-off (HR: 1.9), and post-procedural ankle-brachial index (HR: 0.1). Compared with spot stenting after adjustment using inverse probability of treatment weighting, long stenting, especially involving the P2 or P3 segment of the popliteal artery, was independently associated with 7.5-fold increases in restenosis risk (p < 0.001).ConclusionsThe primary patency was significantly higher with spot stenting than with long stenting following subintimal approach for long femoropopliteal chronic total occlusions. The risk of restenosis was especially higher when long stenting was extended to the distal popliteal artery.     

Fractional Flow Reserve in the Transradial Era: Will Hand Vein Adenosine Infusion Suffice?: A Comparative Study of the Extent,Rapidity, and Stability of Hyperemia From Hand and Femoral Venous Routes of Adenosine Administration

ObjectivesThe aim of this study was to assess adenosine infusion via a cannula in the back of the hand compared with central venous access to achieve peak hyperemia during fractional flow reserve (FFR).BackgroundAdenosine is often used to induce maximal hyperemia when measuring FFR. The gold standard is continuous infusion via a large central vein; however, the increasing use of the transradial route for angiography makes it desirable to have an alternative route for adenosine. Peripheral venous access is frequently obtained in the hand, but concern exists as to whether adenosine delivery from this site can achieve adequate vasodilation for accurate FFR measurement. Our aim was to address this.MethodsSubjects were selected from patients presenting for coronary angiography/intervention who required a pressure-wire study. Subjects received intravenous adenosine infusion sequentially via 2 routes: first, via a 20-gauge hand cannula, and then, after a washout period, via a 5- or 6-F femoral venous sheath. Adenosine was administered at 140 μg/kg/min from each site. Data interpretation was blinded. Minimal FFR achieved with intravenous adenosine from each infusion site was recorded as was the time to peak hyperemia.ResultsPaired (hand and femoral adenosine) recordings taken from 84 vessels in 61 patients were suitable for blinded analysis. The mean FFR measured using adenosine administered via hand and femoral routes was 0.85 with an SD of 0.08 (intraclass correlation = 0.986). Time to peak hyperemia was longer on average with hand-administered adenosine compared with femoral adenosine administration (63 s vs. 43 s; mean difference, 22 s with a 95% confidence interval: 18 s to 27 s; p < 0.0001). Formal comparison of FFR stability using Mann-Whitney analysis (2 tailed) gives p = 0.43, indicating no significant evidence of a difference in stability between the 2 routes.ConclusionsHand vein adenosine infusion produced FFR values very similar to those obtained using central femoral vein adenosine administration, with no systematic bias toward higher or lower reading from 1 site. This has important practical implications for radial access cases involving pressure-wire studies.     

The 24-Month Prognosis of Patients With Positive or Intermediate Results in the Intracoronary Ergonovine Provocation Test

ObjectivesThis study was an observational, multicenter registry to determine clinical characteristics and 24-month prognosis of patients who underwent intracoronary ergonovine provocation tests.BackgroundThe clinical characteristics and prognosis of patients who underwent the ergonovine provocation for vasospastic angina were not fully elucidated.MethodsA total of 2,129 patients in the VA-KOREA (Vasospastic Angina in Korea) registry were classified into positive (n = 454), intermediate (n = 982), and negative (n = 693) groups by intracoronary ergonovine provocation tests. The 24-month incidences of cardiac death, new-onset arrhythmia, and acute coronary syndrome were determined (mean 26.7 ± 8.8 months).ResultsThe number of smokers, frequency of angina before angiography, high-sensitivity C-reactive protein, and triglyceride were higher in the positive group than in other groups. The clinical characteristics of the intermediate and the negative groups were very similar. In the positive group, the incidences of diffuse, focal, and mixed spasm were 65.9%, 23.6%, and 10.6%. Coronary spasm was more frequently provoked on atherosclerotic segments. The 24-month incidences of cardiac death, arrhythmia, and acute coronary syndrome were low (0.9%, 1.6%, and 1.9%, respectively) in the positive group, and there was no cardiac death in the intermediate group (p = 0.02). In the positive group, frequent angina, current smoking, and multivessel spasm were independent predictors for adverse events.ConclusionsThe 24-month prognosis of the positive group in the intracoronary ergonovine provocation test was relatively worse than that of the intermediate group. More intensive clinical attention should be paid to vasospastic angina patients with high-risk factors including frequent angina before angiography, current smoking, and multivessel spasm.     

Outcomes After Percutaneous Coronary Intervention With Stents in Patients Treated With Thoracic External Beam Radiation for Cancer

ObjectivesThe aim of this study was to assess outcomes after percutaneous coronary intervention (PCI) with stents in patients treated with thoracic external beam radiation therapy (EBRT).BackgroundThoracic EBRT for cancer is associated with long-term cardiotoxic sequelae. The impact of EBRT on patients requiring coronary stents is unclear.MethodsWe analyzed outcomes after PCI in cancer survivors treated with curative thoracic EBRT before and after stenting between 1998 and 2012. Reference groups were propensity-matched cohorts with stenting but no EBRT. Primary endpoint was target lesion revascularization (TLR), a clinical surrogate for restenosis. Secondary endpoints included myocardial infarction (MI) and cardiac and overall mortality.ResultsWe identified 115 patients treated with EBRT a median 3.6 years after stenting (group A) and 45 patients treated with EBRT a median 2.2 years before stenting (group B). Long-term mean TLR rates in group A (3.2 vs. 6.6%; hazard ratio: 0.6; 95% confidence interval: 0.2 to 1.6; p = 0.31) and group B (9.2 vs. 9.7%; hazard ratio: 1.2; 95% confidence interval: 0.4 to 3.4; p = 0.79) were similar to rates in corresponding control patients (group A: 1,390 control patients; group B: 439 control patients). Three years post-PCI, group A had higher overall mortality (48.6% vs. 13.9%; p < 0.001) but not MI (4.8% vs. 4.3%; p = 0.93) or cardiac mortality (2.3% vs. 3.6%; p = 0.66) rates versus control patients. There were no significant differences in MI, cardiac, or overall mortality rates in group B.ConclusionsThoracic EBRT is not associated with increased stent failure rates when used before or after PCI. A history of PCI should not preclude the use of curative thoracic EBRT in cancer patients or vice versa. Optimal treatment of cancer should be the goal.     

Randomized Comparisons Between Different Stenting Approaches for Bifurcation Coronary Lesions With or Without Side Branch Stenosis

ObjectivesThis study sought to evaluate the optimal percutaneous coronary intervention techniques using drug-eluting stents for bifurcation coronary lesions.BackgroundThe optimal bifurcation stenting technique needs to be evaluated.MethodsThe trial included 2 randomization studies separated by the presence of side branch (SB) stenosis for patients having non–left main bifurcation lesions. For 306 patients without SB stenosis, the routine final kissing balloon or leave-alone approaches were compared. Another randomization study compared the crush or single-stent approaches for 419 patients with SB stenosis.ResultsBetween the routine final kissing balloon and leave-alone groups for nondiseased SB lesions, angiographic restenosis occurred in 17.9% versus 9.3% (p = 0.064), comprising 15.1% versus 3.7% for the main branch (p = 0.004) and 2.8% versus 5.6% for the SB (p = 0.50) from 214 patients (69.9%) receiving 8-month angiographic follow-up. Incidence of major adverse cardiac events including death, myocardial infarction, or target vessel revascularization over 1 year was 14.0% versus 11.6% between the routine final kissing balloon and leave-alone groups (p = 0.57). In another randomization study for diseased SB lesions, 28.2% in the single-stent group received SB stents. From 300 patients (71.6%) receiving angiographic follow-up, between the crush and single-stent groups, angiographic restenosis rate was 8.4% versus 11.0% (p = 0.44), comprising 5.2% versus 4.8% for the main branch (p = 0.90) and 3.9% versus 8.3% for the SB (p = 0.12). One-year major adverse cardiac events rate between the crush and single-stent groups was 17.9% versus 18.5% (p = 0.84).ConclusionsAngiographic and clinical outcomes were excellent after percutaneous coronary intervention using drug-eluting stents with any stent technique for non–left main bifurcation lesions once the procedure was performed successfully.     

Diagnostic Accuracy of Myocardial Magnetic Resonance Perfusion to Diagnose Ischemic Stenosis With Fractional Flow Reserve as Reference: Systematic Review and Meta-Analysis

ObjectivesThis paper systematically analyzed the performance of magnetic resonance (MR) perfusion to diagnose coronary artery disease (CAD) with fractional flow reserve (FFR) as the reference standard.BackgroundMyocardial MR perfusion has passed the stage of a research technique and has demonstrated the ability to detect functional or ischemic stenosis of coronary arteries. However, the evidence is limited to single-center studies and small sample sizes.MethodsWe searched PubMed and Embase databases for all published studies that evaluated the accuracy of MR perfusion to diagnose CAD versus FFR. We used an exact binomial rendition of the bivariate mixed-effects regression model with test type as a random-effects covariate to synthesize the available data. Based on Bayes’ theorem, the post-test probability was calculated to guide MR perfusion’s clinical utility.ResultsWe identified 14 studies evaluating 1,073 arteries and 650 patients. The pooled sensitivity and specificity were 0.90 (95% confidence interval [CI]: 0.86 to 0.93) and 0.87 (95% CI: 0.82 to 0.90) at the patient level and 0.89 (95% CI: 0.83 to 0.92) and 0.86 (95% CI: 0.77 to 0.92) at the artery and territory levels, respectively. The area under the summary receiver-operating characteristic at the patient level was 0.95 (95% CI: 0.92 to 0.96) and 0.93 (95% CI: 0.91 to 0.95) at the artery and territory levels, respectively. MR perfusion could increase the post-test probability of CAD >80% in patients with a pre-test probability of >37% and can decrease post-test probability of CAD <20% with a pre-test probability of <72%.ConclusionsWith FFR as the reference standard, the diagnostic ability of MR perfusion to detect ischemic CAD is high.     

Effect of Sex Differences on Invasive Measures of Coronary Microvascular Dysfunction in Patients With Angina in the Absence of Obstructive Coronary Artery Disease

ObjectivesThis study investigated sex differences in coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR) in patients with angina in the absence of obstructive coronary artery disease.BackgroundCoronary microvascular dysfunction is associated with worse long-term outcomes, especially in women. Coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR) are 2 methods of assessing the coronary microcirculation.MethodsWe prospectively enrolled 117 women and 40 men with angina in the absence of obstructive coronary artery disease. We performed CFR, IMR, fractional flow reserve, and quantitative coronary angiography in the left anterior descending artery. Coronary flow was assessed with a thermodilution method by obtaining mean transit time (T_mn) (an inverse correlate to absolute flow) at rest and hyperemia.ResultsAll patients had minimal atherosclerosis by quantitative coronary angiography (% diameter stenosis: 23.2 ± 12.3%), and epicardial disease was milder in women (fractional flow reserve: 0.88 ± 0.04 vs. 0.87 ± 0.04; p = 0.04). IMR was similar between the sexes (20.7 ± 9.8 vs. 19.1 ± 8.0; p = 0.45), but CFR was lower in women (3.8 ± 1.6 vs. 4.8 ± 1.9; p = 0.004). This was primarily due to a shorter resting T_mn in women (p = 0.005), suggesting increased resting coronary flow, whereas hyperemic T_mn was identical (p = 0.79). In multivariable analysis, female sex was an independent predictor of lower CFR and shorter resting T_mn.ConclusionsDespite similar microvascular function in women and men by IMR, CFR is lower in women. This discrepancy appears to be due to differences in resting coronary flow between the sexes. The effect of sex differences should be considered in interpretation of physiological indexes using resting coronary flow.     

Pre-Angioplasty Instantaneous Wave-Free Ratio Pullback Provides Virtual Intervention and Predicts Hemodynamic Outcome for Serial Lesions and Diffuse Coronary Artery Disease

ObjectivesThe aim of this study was to perform hemodynamic mapping of the entire vessel using motorized pullback of a pressure guidewire with continuous instantaneous wave-free ratio (iFR) measurement.BackgroundSerial stenoses or diffuse vessel narrowing hamper pressure wire–guided management of coronary stenoses. Characterization of functional relevance of individual stenoses or narrowed segments constitutes an unmet need in ischemia-driven percutaneous revascularization.MethodsThe study was performed in 32 coronary arteries with tandem and/or diffusely diseased vessels. An automated iFR physiological map, integrating pullback speed and physiological information, was built using dedicated software to calculate physiological stenosis severity, length, and intensity (ΔiFR/mm). This map was used to predict the best-case post–percutaneous coronary intervention (PCI) iFR (iFR_exp) according to the stented location, and this was compared with the observed iFR post-PCI (iFR_obs).ResultsAfter successful PCI, the mean difference between iFR_exp and iFR_obs was small (mean difference: 0.016 ± 0.004) with a strong relationship between ΔiFR_exp and ΔiFR_obs (r = 0.97, p < 0.001). By identifying differing iFR intensities, it was possible to identify functional stenosis length and quantify the contribution of each individual stenosis or narrowed segment to overall vessel stenotic burden. Physiological lesion length was shorter than anatomic length (12.6 ± 1.5 vs. 23.3 ± 1.3, p < 0.001), and targeting regions with the highest iFR intensity predicted significant improvement post-PCI (r = 0.86, p < 0.001).ConclusionsiFR measurements during continuous resting pressure wire pullback provide a physiological map of the entire coronary vessel. Before a PCI, the iFR pullback can predict the hemodynamic consequences of stenting specific stenoses and thereby may facilitate the intervention and stenting strategy.     

Stent Thrombosis in Drug-Eluting or Bare-Metal Stents in Patients Receiving Dual Antiplatelet Therapy

ObjectivesThis study sought to compare rates of stent thrombosis and major adverse cardiac and cerebrovascular events (MACCE) (composite of death, myocardial infarction, or stroke) after coronary stenting with drug-eluting stents (DES) versus bare-metal stents (BMS) in patients who participated in the DAPT (Dual Antiplatelet Therapy) study, an international multicenter randomized trial comparing 30 versus 12 months of dual antiplatelet therapy in subjects undergoing coronary stenting with either DES or BMS.BackgroundDespite antirestenotic efficacy of coronary DES compared with BMS, the relative risk of stent thrombosis and adverse cardiovascular events is unclear. Many clinicians perceive BMS to be associated with fewer adverse ischemic events and to require shorter-duration dual antiplatelet therapy than DES.MethodsProspective propensity-matched analysis of subjects enrolled into a randomized trial of dual antiplatelet therapy duration was performed. DES- and BMS-treated subjects were propensity-score matched in a many-to-one fashion. The study design was observational for all subjects 0 to 12 months following stenting. A subset of eligible subjects without major ischemic or bleeding events were randomized at 12 months to continued thienopyridine versus placebo; all subjects were followed through 33 months.ResultsAmong 10,026 propensity-matched subjects, DES-treated subjects (n = 8,308) had a lower rate of stent thrombosis through 33 months compared with BMS-treated subjects (n = 1,718, 1.7% vs. 2.6%; weighted risk difference −1.1%, p = 0.01) and a noninferior rate of MACCE (11.4% vs. 13.2%, respectively, weighted risk difference −1.8%, p = 0.053, noninferiority p < 0.001).ConclusionsDES-treated subjects have long-term rates of stent thrombosis that are lower than BMS-treated subjects. (The Dual Antiplatelet Therapy Study [DAPT study]; NCT00977938)