Usefulness of the Baseline Syntax Score to Predict 3-Year Outcome After Complete Revascularization by Percutaneous Coronary Intervention

Although we strive to achieve complete revascularization (CR) in those receiving percutaneous coronary intervention, it is uncertain which of these patients are at increased risk of clinical events. In this study, we aimed to investigate whether the baseline SYNTAX score (bSS) can predict adverse clinical events in patients receiving CR. From the Efficacy of Xience/Promus Versus Cypher in Reducing Late Loss After Stenting registry, the 3-year patient-oriented composite end point (POCE; all cause death, any myocardial infarction, and any revascularization) was compared according to bSS tertiles (1 ≤ low bSS < 6, 6 ≤ mid-bSS < 10, high bSS ≥ 10). Of the 5,088 patients, CR was achieved in 2,173 by percutaneous coronary intervention. The 3-year POCE increased significantly along with bSS tertile (7.3% vs 8.4% vs 14.8%, p <0.001). Multivariate analysis showed that, despite having the same residual SS of 0, the bSS was an independent predictor of 3-year POCE (hazard ratio 1.038, 95% confidence interval 1.018 to 1.058, p <0.001 per bSS point). In subgroup analysis, bSS was a predictor for 3-year POCE in multivessel diseases (hazard ratio 1.029, 95% confidence interval 1.004 to 1.054, p = 0.025 per bSS point), whereas in single-vessel diseases, the discriminative value of bSS was less significant. Also the clinical SYNTAX score, which added age, creatinine level, and ejection fraction to the bSS, was superior to the bSS in predicting 3-year POCE (area under the curve 0.595 vs 0.649, p = 0.008). In conclusion, the bSS was an independent predictor of long-term clinical outcomes in patients receiving CR, especially in those with multivessel coronary artery disease. Adding clinical factors to the bSS could increase the predictive power of clinical outcomes.

Abstract 65: Latrophilin-2 is a Specific Cell-surface Marker for Cardiac Progenitor Cells and Specifies Cardiac Lineage Commitment and Development

Backgrounds: The identification of a lineage-specific marker plays a pivotal role in understanding developmental process and is utilized to isolate a certain cell type with high purity for the therapeutic purpose. We here report a new cardiac-specific marker, and demonstrate its functional significance in the cardiac development.

Methods and Results: When mouse pluripotent stem cells (ES and iPS cells) were stimulated with BMP4, Activin A, bFGF and VEGF, they differentiated into cardiac cells. To screen cell-surface expressing molecules on cardiac progenitor cells compared to undifferentiated mouse iPS and ES cells, we isolated Flk1+/PDGFRa+ cells at differentiation day 4 and performed microarray analysis. Among candidates, we identified a new G protein-coupled receptor, Latrophilin-2 (LPHN2) whose signaling pathway and its effect on cardiac differentiation is unknown. In sorting experiments under cardiac differentiation condition, LPHN2+ cells derived from pluripotent stem cells strongly expressed cardiac-related genes (Mesp1, Nkx2.5, aMHC and cTnT) and exclusively gave rise to beating cardiomyocytes, as compared with LPHN2- cells. LPHN2-/- mice revealed embryonically lethal and huge defects in cardiac development. Interestingly, LPHN2+/- heterozygotes were alive and fertile. For the purpose of cardiac regeneration, we transplanted iPS-derived LPHN2+ cells into the infarcted heart of adult mice. LPHN2+ cells differentiated into cardiomyocytes, and systolic function of left ventricle was improved and infarct size was reduced. We confirmed LPHN2 expression on human iPS and ES cell-derived cardiac progenitor cells and human heart.

Conclusions: We demonstrate that LPHN2 is a functionally significant and cell-surface expressing marker for both mouse and human cardiac progenitor and cardiomyocytes. Our findings provide a valuable tool for isolating cardiac lineage cells from pluripotent stem cells and an insight into cardiac development and regeneration.

Usefulness of combined intravascular ultrasound parameters to predict functional significance of coronary artery stenosis and determinants of mismatch

AIMS

Efficacy of combined intravascular ultrasound (IVUS) parameters in functional significance prediction and discrepancy between IVUS and fractional flow reserve (FFR) have not been well defined. This study therefore aimed to: 1) evaluate the diagnostic accuracy of combined IVUS parameters, namely minimal lumen area (MLA) and percent plaque burden (%PB), in functional significance prediction of coronary artery stenosis; and 2) define factors that affect the relation between FFR value and IVUS parameters.

METHODS AND RESULTS

At 11 international centres, IVUS and FFR measurements were concurrently performed in 945 major epicardial coronary artery lesions (886 patients). Functional significance was defined as FFR ≤0.8. MLA and FFR correlated weakly (r=0.289, p<0.001). Diagnostic accuracy of MLA ≤4.0 mm2, %PB >70% and their combination were 50%, 47% and 51%, respectively, with similar area under the curve (AUC) of 0.561, 0.511 and 0.516, respectively. The best cut-off values (BCV) were MLA ≤3.0 mm2 and %PB >75%, with accuracy of 60% for MLA, 50% for %PB and 56% for their combination, and AUC of 0.618, 0.511 and 0.533, respectively. MLA BCV ≤3.0 mm2 had higher predictive power than %PB BCV >75% or their combination. Independent predictors of functional significance were male gender (odds ratio 1.76 [95% confidence interval: 1.19-2.62]), left ventricular ejection fraction (LVEF, 0.98 [0.96-0.99]), LAD lesion (2.52 [1.73-3.67]), reference vessel diameter (0.60 [0.41-0.86]), lesion length (1.04 [1.02-1.06]) and MLA (0.79 [0.69-0.92]). False negative lesion incidence was 24.4% in association with race (for Asians, 0.391 [0.219-0.698]), LAD lesion (2.677 [1.709-4.191]) and LVEF (0.977 [0.957-0.997]). False positive lesion incidence was 17.0% in association with non-LAD lesion (2.444 [1.620-3.686]).

CONCLUSIONS

Combined IVUS parameters did not improve the accuracy of functional significance prediction. Discrepancy between IVUS and FFR, which was not rare, should be taken into account in clinical decision making.

Harmonizing Optimal Strategy for Treatment of coronary artery diseases--comparison of REDUCtion of prasugrEl dose or POLYmer TECHnology in ACS patients (HOST-REDUCE-POLYTECH-ACS RCT): study protocol for a randomized controlled trial

Background

Antiplatelet treatment is an important component in optimizing the clinical outcomes after percutaneous coronary intervention (PCI) especially in patients with acute coronary syndrome (ACS). Prasugrel, which is a new P2Y12 inhibitor, has been confirmed as efficacious in a large trial in Western countries, and a similar trial is also to be launched in Asian countries. Although a 60-mg loading dose of prasugrel followed by 10 mg per day should be acceptable, there have been no data regarding the optimal dose in Asian patients. Furthermore, serum levels of prasugrel and the rates of platelet inhibition are known to be higher in Asians than Caucasians with the same dose of the drug.

Polymer, a key component of drug-eluting stents (DES), has been suggested as the cause of inflammation leading to late complications, and has driven many companies to develop biodegradable-polymer DES. Currently, there are limited data regarding the head-to-head comparison between BP-BES and the biostable polymer CoCr-EES or the newest platinum-chromium everolimus-eluting stent (PtCr-EES). Furthermore, the polymer issue may be more important in ACS where there is ruptured thrombotic plaque where polymer-induced inflammation may affect the local milieu of the stented artery.

Therefore, the present study dedicated only to ACS patients, will offer important information on the optimal prasugrel dose in the Asian population by comparing a 10-mg versus a 5-mg maintenance dose beyond 1 month after PCI, as well as giving important insight into the polymer issue by comparing BP-BES versus biostable-polymer PtCr-EES.

Method/Design

Harmonizing Optimal Strategy for Treatment of coronary artery diseases – comparison of REDUCtion of prasugrEl dose or POLYmer TECHnology in ACS patients (HOST-REDUCE-POLYTECH-ACS) trial is a multicenter, randomized and open-label clinical study with a 2 × 2 factorial design, according to the type of stent (PtCr-EES versus BP-BES) and prasugrel maintenance dose (5 mg versus 10 mg), to demonstrate non-inferiority of PtCr-EES relative to BP-BES or the reduced prasugrel dose relative to conventional dose in an Asian all-comers PCI population presenting with ACS. Approximately 3400 patients will undergo prospective, random assignment separately to either stent or prasugrel arm (1:1 ratio, respectively). When the patients have contraindications to prasugrel, they are categorized into an antiplatelet observation group after stent-randomization. The primary endpoint is the patient-oriented composite outcome, which is a composite of all-cause mortality, any myocardial infarction (MI), any repeat revascularization in the stent arm at 12 months after index PCI. In the prasugrel arm, primary endpoint is any major adverse cardiovascular event, which is a composite of all-cause mortality, any MI, any stent thrombosis (Academic Research Consortium (ARC)-defined), any repeat revascularization, stroke, or bleeding (BARC class ≥ 2).

Discussion

The HOST-REDUCE-POLYTECH-ACS RCT is the first study exploring the optimal maintenance dose of prasugrel beyond 1 month after PCI for ACS in Asian all-comers. In addition, this is the largest study dedicated only to ACS patients to evaluate the polymer issue in the situation of ACS by directly comparing biostable-polymer PtCr-EES versus BP-BES.

Trial registration

ClinicalTrials.gov (ID: NCT02193971, 13 July 2014).

Long-Term Patient-Related and Lesion-Related Outcomes After Real-World Fractional Flow Reserve Use

BACKGROUND

Long-term clinical outcomes of real-world use of fractional flow reserve (FFR), including the decisions against FFR, have not been fully evaluated in the era of drug-eluting stent (DES) implantation.

METHODS

A total of 1294 patients who underwent FFR measurement for de novo coronary lesions were included. FFR measured lesions (n = 1628) were divided into FFR-defer or FFR-stent lesions according to the treatment strategy selected after FFR measurement. Clinical outcomes were assessed by patient-related major adverse cardiac event (a composite of all-cause death, myocardial infarction, and any revascularization) and target-lesion related event (target-lesion related myocardial infarction and revascularization).

RESULTS

Mean FFR was 0.80 ± 0.12, and FFR was ≤0.8 in 728 lesions (44.7%). Five-year cumulative all-death rate was 6.3%, myocardial infarction rate was 1.5%, and rate of any revascularization was 12.5%. Among 797 deferred lesions, 105 lesions had FFR ≤0.8 and those lesions had a higher risk of 5-year target-lesion related events than the lesions with FFR >0.8 (21.2% vs 6.6%, respectively; P=.03). By multivariate analyses, the determinant for the 1-year target-lesion related events was the presence of diabetes (hazard ratio, 3.74; 95% confidence interval, 1.45-9.67; P=.01), while the determinant for delayed events at 1-5 years was FFR ≤0.8 (hazard ratio, 4.50; 95% confidence interval, 1.65-12.28; P=.01). Angiographic lesion severity was not an independent predictor for clinical events during follow-up among deferred lesions.

CONCLUSION

The deferral of stenting according to FFR was associated with favorable long-term outcomes. Presence of diabetes and low FFR (≤0.8) increased the risk of clinical events in deferred lesions.

Switching bipolar hepatic radiofrequency ablation using internally cooled wet electrodes: comparison with consecutive monopolar and switching monopolar modes

OBJECTIVE

To evaluate whether switching bipolar radiofrequency ablation (SB-RFA) using three internally cooled wet (ICW) electrodes can induce coagulations >5 cm in porcine livers with better efficiency than consecutive monopolar (CM) or switching monopolar (SM) modes.

METHODS

A total of 60 coagulations were made in 15 in vivo porcine livers using three 17-gauge ICW electrodes and a multichannel radiofrequency (RF) generator. RF energy (approximately 200 W) was applied in CM mode (Group A, n = 20) for 24 min, SM mode for 12 min (Group B, n = 20) or switching bipolar (SB) mode for 12 min (Group C, n = 20) in in vivo porcine livers. Thereafter, the delivered RFA energy, as well as the shape and dimension of coagulations were compared among the groups.

RESULTS

Spherical- or oval-shaped ablations were created in 30% (6/20), 85% (17/20) and 90% (18/20) of coagulations in the CM, SM and SB groups, respectively (p = 0.003). SB-RFA created ablations >5 cm in minimum diameter (Dmin) in 65% (13/20) of porcine livers, whereas SM- or CM-RFA created ablations >5 cm in only 25% (5/20) and 20% (4/20) of porcine livers, respectively (p = 0.03). The mean Dmin of coagulations was significantly larger in Group C than in Groups A and B (5.1 ± 0.9, 3.9 ± 1.2 and 4.4 ± 1.0 cm, respectively, p = 0.002) at a lower delivered RF energy level (76.8 ± 14.3, 120.9 ± 24.5 and 114.2 ± 18.3 kJ, respectively, p < 0.001).

CONCLUSION

SB-RFA using three ICW electrodes can create coagulations >5 cm in diameter with better efficiency than do SM- or CM-RFA.

ADVANCES IN KNOWLEDGE

SB-RFA can create large, regular ablation zones with better time-energy efficiency than do CM- or SM-RFA.

Comparison among drug-eluting balloon, drug-eluting stent, and plain balloon angioplasty for the treatment of in-stent restenosis: a network meta-analysis of 11 randomized, controlled trials

OBJECTIVES

A Bayesian network meta-analysis was performed comparing the efficacy and safety of drug-eluting balloons (DEB), drug-eluting stents (DES), or plain old balloon angioplasty (POBA) for treatment of in-stent restenosis (ISR).

BACKGROUND

Optimal treatment options for ISR have not been well established.

METHODS

Randomized, controlled trials comparing DEB, DES, and POBA for the treatment of ISR after percutaneous coronary intervention with bare metal stent or DES were included. The primary outcome was target lesion revascularization (TLR). The pairwise posterior median odds ratio (OR) with 95% credible interval (CrI) was the effect measure.

RESULTS

This analysis included 2,059 patients from 11 RCTs. The risk of TLR was markedly lower in patients treated with DEB (OR: 0.22, 95% CrI: 0.10 to 0.42) or DES (OR: 0.24, 95% CrI: 0.11 to 0.47) than in those treated with POBA in a random-effects model. In a comparison of DEB and DES, the risk of TLR (OR: 0.92, 95% CrI: 0.43 to 1.90) was similar. The risk of MI or all-cause mortality was lowest in the DEB group compared with the DES and POBA groups, which did not meet statistical significance. The risk of major adverse cardiac events, which was mainly driven by TLR, was also significantly lower in the DEB or and DES group (OR: 0.28, 95% CrI: 0.14 to 0.53) than in the POBA group, but it was similar between the DEB and DES groups (OR: 0.84, 95% CrI: 0.45 to 1.50). The probability of being ranked as the best treatment was 59.9% (DEB), 40.1% (DES), and 0.1% (POBA) in terms of TLR, whereas it was 63.0% (DEB), 35.3% (POBA), and 1.7% (DES) in terms of MI.

CONCLUSIONS

Local drug delivery by DEB or DES for ISR lesions was markedly better than POBA in preventing TLR, but not for MI or mortality. Among the 2 different strategies of drug delivery for ISR lesions, treatment with DEB showed a trend of less development of MI than did treatment with DES.

Efficacy of short-term high-dose statin pretreatment in prevention of contrast-induced acute kidney injury: updated study-level meta-analysis of 13 randomized controlled trials

BACKGROUND

There have been conflicting results across the trials that evaluated prophylactic efficacy of short-term high-dose statin pre-treatment for prevention of contrast-induced acute kidney injury (CIAKI) in patients undergoing coronary angiography (CAG). The aim of the study was to perform an up-to-date meta-analysis regarding the efficacy of high-dose statin pre-treatment in preventing CIAKI.

METHODS AND RESULTS

Randomized-controlled trials comparing high-dose statin versus low-dose statin or placebo pre-treatment for prevention of CIAKI in patients undergoing CAG were included. The primary endpoint was the incidence of CIAKI within 2-5 days after CAG. The relative risk (RR) with 95% CI was the effect measure. This analysis included 13 RCTs with 5,825 total patients; about half of them (n = 2,889) were pre-treated with high-dose statin (at least 40 mg of atorvastatin) before CAG, and the remainders (n = 2,936) pretreated with low-dose statin or placebo. In random-effects model, high-dose statin pre-treatment significantly reduced the incidence of CIAKI (RR 0.45, 95% CI 0.35-0.57, p<0.001, I(2)= 8.2%, NNT 16), compared with low-dose statin or placebo. The benefit of high-dose statin was consistent in both comparisons with low-dose statin (RR 0.47, 95% CI 0.34-0.65, p<0.001, I(2) = 28.4%, NNT 19) or placebo (RR 0.34, 95% CI 0.21-0.58, p<0.001, I(2)= 0.0%, NNT 16). In addition, high-dose statin showed significant reduction of CIAKI across various subgroups of chronic kidney disease, acute coronary syndrome, and old age (≥ 60 years), regardless of osmolality of contrast or administration of N-acetylcystein.

CONCLUSIONS

High-dose statin pre-treatment significantly reduced overall incidence of CIAKI in patients undergoing CAG, and emerges as an effective prophylactic measure to prevent CIAKI.

Three-year patient-related and stent-related outcomes of second-generation everolimus-eluting Xience V stents versus zotarolimus-eluting resolute stents in real-world practice (from the Multicenter Prospective EXCELLENT and RESOLUTE-Korea Registries)

Long-term outcomes are imperative to confirm safety of drug-eluting stents. There have been 2 randomized controlled trials comparing everolimus-eluting stents (EESs) and Resolute zotarolimus-eluting stents (ZES-Rs). To date, long-term clinical outcomes of these stents were limited to only 1 report, which has recently reported 4-year comparisons of these stents. Therefore, more evidence is needed regarding long-term clinical outcomes of the second-generation stents. This study compared the long-term clinical outcomes of EES with ZES-R in "all-comer" cohorts up to 3-year follow-up. The EXCELLENT and RESOLUTE-Korea registries prospectively enrolled 3,056 patients treated with EES and 1,998 with ZES-R, respectively, without exclusions. Stent-related composite outcomes (target lesion failure) and patient-related composite events up to 3-year follow-up were compared in crude and propensity score-matched analyses. Of 5,054 patients, 3,830 patients (75.8%) had off-label indication (2,217 treated with EES and 1,613 treated with ZES-R). The stent-related outcome (189 [6.2%] vs 127 [6.4%], p = 0.812) and the patient-related outcome (420 [13.7%] vs 250 [12.5%], p = 0.581) did not differ between EES and ZES-R, respectively, at 3 years, which was corroborated by similar results from the propensity score-matched cohort (hazard ratio [HR] 0.92, 95% confidence interval [CI] 0.70 to 1.20, p = 0.523 and 0.85, 95% CI 0.70 to 1.02, p = 0.081, for stent- and patient-related outcomes, respectively). The rate of definite or probable stent thrombosis up to 3 years (22 [0.7%] vs 10 [0.5%], p = 0.370) was also similar. The rate of very late definite or probable stent thrombosis was very low and comparable between the 2 stents (3 [0.1%] vs 1 [0.1%], p = 0.657). In multivariate analysis, chronic renal failure (adjusted HR 3.615, 95% CI 2.440 to 5.354, p <0.001) and off-label indication (adjusted HR 1.782, 95% CI 1.169 to 2.718, p = 0.007) were the strongest predictors of target lesion failure at 3 years. In conclusion, both stents showed comparable safety and efficacy at 3-year follow-up in this robust real-world registry with unrestricted use of EES and ZES-R. Overall incidences of target lesion failure and definite stent thrombosis, including very late stent thrombosis, were low, even in the patients with off-label indications, suggesting excellent long-term safety and sustained efficacy of both types of second-generation drug-eluting stents.

Direct Conversion of Adult Skin Fibroblasts to Endothelial Cells by Defined Factors

Background—

Cell-based therapies to augment endothelial cells (ECs) hold great therapeutic promise. Here, we report a novel approach to generate functional ECs directly from adult fibroblasts.

Methods and Results—

Eleven candidate genes that are key regulators of endothelial development were selected. Green fluorescent protein (GFP)–negative skin fibroblasts were prepared from Tie2-GFP mice and infected with lentiviruses allowing simultaneous overexpression of all 11 factors. Tie2-GFP + cells (0.9%), representing Tie2 gene activation, were detected by flow cytometry. Serial stepwise screening revealed 5 key factors (Foxo1, Er71, Klf2, Tal1, and Lmo2) that were required for efficient reprogramming of skin fibroblasts into Tie2-GFP + cells (4%). This reprogramming strategy did not involve pluripotency induction because neither Oct4 nor Nanog was expressed after 5 key factor transduction. Tie2-GFP + cells were isolated using fluorescence-activated cell sorting and designated as induced ECs (iECs). iECs exhibited endothelium-like cobblestone morphology and expressed EC molecular markers. iECs possessed endothelial functions such as Bandeiraea simplicifolia -1 lectin binding, acetylated low-density lipoprotein uptake, capillary formation on Matrigel, and nitric oxide production. The epigenetic profile of iECs was similar to that of authentic ECs because the promoters of VE-cadherin and Tie2 genes were demethylated. mRNA profiling showed clustering of iECs with authentic ECs and highly enriched endothelial genes in iECs. In a murine model of hind-limb ischemia, iEC implantation increased capillary density and enhanced limb perfusion, demonstrating the in vivo viability and functionality of iECs.

Conclusions—

We demonstrated the first direct conversion of adult fibroblasts to functional ECs. These results suggest a novel therapeutic modality for cell therapy in ischemic vascular disease.

Activated platelet supernatant can augment the angiogenic potential of human peripheral blood stem cells mobilized from bone marrow by G-CSF

Platelets not only play a role in hemostasis, but they also promote angiogenesis and tissue recovery by releasing various cytokines and making an angiogenic milieu. Here, we examined autologous 'activated platelet supernatant (APS)' as a priming agent for stem cells; thereby enhance their pro-angiogenic potential and efficacy of stem cell-based therapy for ischemic diseases. The mobilized peripheral blood stem cells ((mob)PBSCs) were isolated from healthy volunteers after subcutaneous injection of granulocyte-colony stimulating factor. APS was collected separately from the platelet rich plasma after activation by thrombin. (mob)PBSCs were primed for 6h before analysis. Compared to naive platelet supernatants, APS had a higher level of various cytokines, such as IL8, IL17, PDGF and VEGF. APS-priming for 6h induced (mob)PBSCs to express key angiogenic factors, surface markers (i.e. CD34, CD31, and CXCR4) and integrins (integrins α5, β1 and β2). Also (mob)PBSCs were polarized toward CD14(++)/CD16(+) pro-angiogenic monocytes. The priming effect was reproduced by an in vitro reconstruction of APS. Through this phenotype, APS-priming increased cell-cell adhesion and cell-extracellular matrix adhesion. The culture supernatant of APS-primed (mob)PBSCs contained high levels of IL8, IL10, IL17 and TNFα, and augmented proliferation and capillary network formation of human umbilical vein endothelial cells. In vivo transplantation of APS-primed (mob)PBSCs into athymic mice ischemic hindlimbs and Matrigel plugs elicited vessel differentiation and tissue repair. In safety analysis, platelet activity increased after mixing with (mob)PBSCs regardless of priming, which was normalized by aspirin treatment. Collectively, our data identify that APS-priming can enhance the angiogenic potential of (mob)PBSCs, which can be used as an adjunctive strategy to improve the efficacy of cell therapy for ischemic diseases.

Mechanism of edge restenosis after drug-eluting stent implantation. Angulation at the edge and mechanical properties of the stent

BACKGROUND

Edge restenosis is not an unusual finding after implantation of drug-eluting stents (DES). We hypothesized that mechanical stress imposed on the stent edge would cause vessel wall injury and inflammation, which may consequently lead to edge restenosis.

METHODS AND RESULTS

In total, 1,496 patients were implanted with a sirolimus-eluting stent (SES), paclitaxel-eluting stent (PES) or zotarolimus-eluting stent (ZES) in Seoul National University Hospital between 2007 and 2009. Binary restenosis occurred in 161 lesions in 119 patients. We retrospectively compared the 3 DES with regard to the percentage of edge stent restenosis among all cases of restenosis. We also evaluated the maximal, minimal, and Δ (maximal angle-minimal angle) angles. The percentage of edge restenosis was higher for SES than for ZES (37.5% vs. 16.7%, P=0.017). Maximal angle at the proximal edge was 64.82°±33.46° for 26 stents with proximal edge restenosis compared with 31.84°±31.51° for 89 stents without proximal edge restenosis (P=0.001). The Δ angle was also significantly different between the 2 groups (14.81°±15.98° vs. 7.60°±8.86°, P=0.035). Similar findings were observed for distal edge restenosis. Both the maximal angle (39.09°±21.04° vs. 22.71°±22.83°, P=0.010) and Δ angle (20.23°±15.39° vs. 9.18°±9.66°, P=0.016) at the distal edge were significantly different between the 2 groups.

CONCLUSIONS

Physical stress determined by angulation at the stent edge segment and biomechanical properties of the DES can be considered as one of the plausible mechanisms for edge stent restenosis.

Paraoxonase 1 gene polymorphism does not affect clopidogrel response variability but is associated with clinical outcome after PCI

Background

Paraoxonase (PON) is a high-density-lipoprotein (HDL) associated enzyme with antioxidative and anti-atherogenic property. Its function is associated with coronary artery disease and its activity genetically controlled. We evaluated whether genetic variation of PON-1 is associated with clinical outcome in a large cohort of Korean patients with drug-eluting stents implantation.

Methods

A total of 1676 patients with drug-eluting stent implantation were enrolled in the prospective CROSS-VERIFY cohort from June 2006 to June 2010. We genotyped the PON1-Q192R gene, measured clopidogrel on-treatment platelet reactivity (OPR), and analyzed lipid profiles. The primary endpoint was the composite of cardiac death, myocardial infarction, and stent thrombosis at 12 months.

Results

PON-1 genotyping data were available in 1336 patients. Since the Q-allele is associated with decreased PON-activity, we analyzed the outcome between patients with QQ/QR (815 patients, 61%) and those with RR-genotype (521 patients, 39%). After adjustment for common cardiac risk factors, the QQ/QR-genotype was an independent predictor of the primary thrombotic endpoint with an 11-fold increased risk (HR 11.6, 95% CI: 1.55–87.0), but not repeat revascularization (HR 1.12, 95% CI: 0.78–1.61). The QQ/QR-genotype was not associated with OPR (QQ/QR: 231±86 PRU vs. RR 236±82 PRU, p = 0.342) but higher small-dense LDL levels (1.20±0.12 mg/dL vs. 0.76±0.15 mg/dL, p = 0.027). The increased risk of thrombotic outcomes was more profound in acute coronary syndrome (ACS) patients compared with non-ACS patients.

Conclusion

PON1 Q-allele is an independent predictor of worse cardiovascular outcome independent of platelet function and is associated with significantly higher levels of small dense LDL-C.

CYP3A4 genetic status may be associated with increased vulnerability to the inhibitory effect of calcium-channel blockers on clopidogrel

BACKGROUND

Calcium-channel blockers (CCBs) inhibit the CYP3A4 enzyme, which is involved in clopidogrel activation. Studies have shown conflicting results regarding the effect of concomitant CCB administration on clopidogrel response. We investigated the relationship between CYP3A4 genotype and the inhibitory effect of CCBs on clopidogrel response.

METHODS AND RESULTS

Clopidogrel on-treatment platelet reactivity (OPR) was measured and CYP3A4 (IVS10+12G>A) genotyped in 1,247 consecutive patients with drug-eluting stent implantation. The mean OPR was 231±83 (P2Y12 reaction units: PRU). In total, 332 (26.6%) CCB users had higher OPR compared with 915 (73.4%) non-CCB users (245±84 vs. 227±83 PRU, P=0.001). The distribution of CYP3A4 (IVS10+12G>A) genotype was 63.6%, 32.6% and 3.8% for GG, GA and AA genotypes, respectively. After adjustment for possible confounding factors, the number of A-alleles was associated with increased vulnerability to CCB use (effect of CCB use ΔPRU: +8 PRU, P=0.210, +24 PRU, P=0.012, +50 PRU, P=0.025, for patients with 0, 1, and 2 A-alleles, respectively, +24 PRU, P=0.005 for GA/AA genotypes). Furthermore, only in the GA/AA-genotype did CCB use result in a significantly increased risk for high-OPR (odds ratio 1.84, 95% confidence interval 1.15-2.92, P=0.010).

CONCLUSIONS

CCB use is associated with increased OPR. The number of CYP3A4 (IVS10+12G>A) A-alleles may be associated with an increased vulnerability to the effects of CCBs on clopidogrel response variation. 

Genetic determinants of clopidogrel responsiveness in Koreans treated with drug-eluting stents

BACKGROUND

Variations of genes encoding cytochrome enzymes, drug transporters, and paraoxonase have recently been reported to be associated with clopidogrel response variability besides the well-known CYP2C19 loss-of-function (LOF) alleles. We determined whether newly reported genetic variations are associated with clopidogrel on-treatment platelet reactivity (OPR) in Korean patients.

METHODS

OPR was measured in 1264 consecutive patients who underwent percutaneous coronary intervention using the VerifyNowP2Y12 assay system and genotyping of PON-1 Q192R, ABCB1 C3435T, CYP1A2*1F, CYP2B6*6, CYP2C19*2, CYP2C19*3, CYP2C19*17, CYP3A4 (IVS10+12G>A), and CYP3A5*3 was performed. We applied two different cutoffs, i.e. 240 P2Y12 reaction units (PRU) and 253 PRU, to define high OPR.

RESULTS

Mean OPR of the entire population was 231±83 PRU. Genetic variations of ABCB1 and PON-1 genes as well as that of CYP1A2, 2B6, 3A4, and 3A5 were not associated with clopidogrel response variability. As for CYP2C19, patients were classified into 4 metabolism genotypes: 0.6% ultrarapid (UM), 40.3% extensive (EM), 48.8% intermediate (IM), and 10.3% poor metabolizers (PM). After adjustment for possible confounders, CYP2C19 metabolism genotype was associated with a significant increase in OPR: effect on OPR-difference: +27 PRU, p=0.015 for EM, +53 PRU, p<0.001 for IM, and +74 PRU, p=0.006 for PM compared with UM. In multivariable analysis, the CYP2C19 genotype was the only independent predictor of high-OPR among genetic variations using two different cutoffs.

CONCLUSIONS

Among genes postulated to be involved in clopidogrel metabolism, only the CYP2C19 genotype is associated with response variability and emerged as an independent predictor of high-OPR using two different cutoffs. PON-1 and ABCB1 genetic variants do not affect clopidogrel OPR in Korean patients.