Prediction and impact of failure of transradial approach for primary percutaneous coronary intervention.

OBJECTIVES: To determine predictors of failure of transradial approach (TRA) in patients with ST elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI), and develop a novel score specific for this population. METHODS: Consecutive patients with STEMI undergoing primary PCI in a tertiary care high-volume radial centre were included. TRA-PCI failure was categorised as primary (primary transfemoral approach (TFA)) or crossover (from TRA to TFA). Multivariate analysis was performed to determine independent predictors of TRA-PCI failure, and an integer risk score was developed. Clinical outcomes up to 1 year were assessed. RESULTS: From January 2006 to January 2011, 2020 patients were studied. Primary TRA-PCI failure occurred in 111 (5%) patients and crossover to TFA in 44 (2.2%) patients. Independent predictors of TRA-PCI failure were: weight ≤65 kg (OR: 3.0; 95% CI 1.9 to 4.8, p<0.0001), physician with ≤5% TFA conversion (OR: 0.45; 95% CI 0.2 to 0.9, p=0.033), and physician with ≥10% conversion to TFA (OR: 2.2; 95% CI 1.2 to 3.7, p=0.005), intra-aortic balloon pump (OR: 2.0; 95% CI 0.9 to 4.3, p=0.066), cardiogenic shock (OR: 2.8; 95% CI 1.4 to 5.6, p=0.0035), endotracheal intubation (OR: 107; 95% CI 42 to 339, p<0.0001), creatinine >133 µmol/L (OR: 3.6; 95% CI 1.9 to 6.8, p<0.0001), age ≥75 (OR: 1.7; 95% CI 1.0 to 2.9, p=0.031), prior PCI (OR: 2.6; 95% CI 1.5 to 4.5, p=0.0009), hypertension (OR: 1.8; 95% CI 1.2 to 2.9, p=0.009). An integer risk score ranging from -1 to 12 was developed, and predicted TRA-PCI failure from 0% to 100% (c-statistic of 0.868; 95% CI 0.866 to 0.869). Mortality at 1 year remained significantly higher after TRA-PCI failure (adjusted OR 2.2; 95% CI 1.2 to 3.9, p=0.011). CONCLUSIONS: In a high-volume radial centre, the incidence of TRA-PCI failure is low and can be accurately predicted using a 9-variables risk score. Since outcomes after TRA-PCI failure remained inferior, further effort to maximise the use of radial approach for primary PCI should be investigated.

Changes in CYP2C19 enzyme activity evaluated by the [(13)C]-pantoprazole breath test after co-administration of clopidogrel and proton pump inhibitors following percutaneous coronary intervention and correlation to platelet reactivity.

Dual antiplatelet therapy (DAPT) with clopidogrel and aspirin is used for the prevention of cardiovascular events following percutaneous coronary intervention (PCI). These agents increase the risk of gastrointestinal bleeding. To prevent these events, proton pump inhibitors (PPI) are routinely prescribed. It has been reported that with the exception of pantoprazole and dexlanzoprazole, PPIs can impede conversion of clopidogrel by cytochrome P450 2C19 (CYP2C19) to its active metabolite, a critical step required for clopidogrel efficacy. Changes in CYP2C19 enzyme activity (phenotype) and its correlation with platelet reactivity following PPI therapy has not yet been fully described. In this study we attempted to determine if the [ (13)C]-pantoprazole breath test (Ptz-BT) can evaluate changes in CYP2C19 enzyme activity (phenoconversion) following the administration of PPI in coronary artery disease (CAD) patients treated with DAPT after PCI. Thirty (30) days after successful PCI with stent placement, 59 patients enrolled in the Evaluation of the Influence of Statins and Proton Pump Inhibitors on Clopidogrel Antiplatelet Effects (SPICE) trial (ClinicalTrials.gov Identifier: NCT00930670) were recruited to participate in this sub study. Patients were randomized to one of 4 antacid therapies (omeprazole, esomeprazole. pantoprazole or ranitidine). Subjects were administered the Ptz-BT and platelet function was evaluated by vasodilator-stimulated phosphoprotein (VASP) phosphorylation and light transmittance aggregometry before and 30 d after treatment with antacid therapy. Patients randomized to esomeprazole and omeprazole had greater high on-treatment platelet reactivity and lowering of CYP2C19 enzyme activity at Day 60 after 30 d of PPI therapy. Patients randomized to ranitidine and pantoprazole did not show any changes in platelet activity or CYP 2C19 enzyme activity. In patients treated with esomeprazole and omeprazole, changes in CYP2C19 enzyme activity (phenoconversion) correlated well with changes in platelet reactivity. Co-administration of omeprazole or esomeprazole in patients treated with clopidogrel results in lower CYP2C19 enzyme activity and increased platelet reactivity as measured by VASP phosphorylation test while patients given pantoprazole or ranitidine did not show any significant changes in CYP2C19 enzyme activity and platelet reactivity.

Interaction of chronic total occlusion and chronic kidney disease in patients undergoing primary percutaneous coronary intervention for acute ST-elevation myocardial infarction.

Chronic total occlusion (CTO) in a non-infarct-related artery and chronic kidney failure (CKD) are associated with worse outcomes after primary percutaneous coronary intervention (PCI). The aim of this study was to investigate the interaction of CTO and CKD in patients who underwent primary PCI for acute ST-segment elevation myocardial infarction (STEMI). Patients with STEMIs with or without CKD, defined as an estimated glomerular filtration rate <60 ml/min/1.73 m(2), were categorized into those with single-vessel disease and those with multivessel disease with or without CTO. The primary outcomes were the incidence of 30-day and 1-year mortality. Among 1,873 consecutive patients with STEMIs included between 2006 and 2011, 336 (18%) had CKD. The prevalence of CTO in a non-infarct-related artery was 13% in patients with CKD compared with 7% in those without CKD (p = 0.0003). There was a significant interaction between CKD and CTO on 30-day mortality (p = 0.018) and 1-year mortality (p = 0.013). Independent predictors of late mortality in patients with CKD were previous myocardial infarction (hazard ratio [HR] 1.71, 95% confidence interval [CI] 1.01 to 2.79), age >75 years (HR 1.86, 95% CI 1.19 to 2.95), a left ventricular ejection fraction after primary PCI <40% (HR 2.20, 95% CI 1.36 to 3.63), left main culprit artery (HR 4.46, 95% CI 1.64 to 10.25), and shock (HR 7.44, 95% CI 4.56 to 12.31), but multivessel disease with CTO was not a predictor. In contrast, multivessel disease with CTO was an independent predictor of mortality in patients without CKD (HR 3.30, 95% CI 1.70 to 6.17). In conclusion, in patients with STEMIs who underwent primary PCI, with preexisting CKD, the prevalence of CTO in a non-infarct-related artery was twice as great. In these patients, the clinical impact of CTO seems to be overshadowed by the presence of CKD.

Effect on door-to-balloon time of immediate transradial percutaneous coronary intervention on culprit lesion in ST-elevation myocardial infarction compared to diagnostic angiography followed by primary percutaneous coronary intervention.

Door-to-balloon (DTB) time is an important metric in primary percutaneous coronary intervention (PCI) for acute ST-segment elevation myocardial infarction to optimize clinical outcomes. The aim of this study was to compare the impact of immediate PCI on culprit lesions in patients with ST-segment elevation myocardial infarctions versus diagnostic angiography followed by PCI on DTB times and procedural data at a high-volume tertiary care radial center. All patients who underwent primary PCI <12 hours after symptom onset were studied. Procedural data and all-cause mortality were assessed in all patients. The primary outcome was DTB time. From January 2006 to June 2011, 1,900 patients were included and divided into 2 groups: 562 patients (30%) underwent primary PCI followed by contralateral diagnostic angiography, and 1,338 patients (70%) underwent diagnostic angiography before primary PCI. No significant differences were observed in baseline characteristics. Left anterior descending coronary artery-related ST-segment elevation myocardial infarctions were more often found in patients who underwent PCI first (54% vs 34%, p <0.0001). Overall, there was a reduction of 8 minutes in DTB time between patients who underwent PCI first and those who underwent angiography first (32 minutes [interquartile range 24 to 52] vs 40 minutes [interquartile range 30 to 69], respectively, p <0.0001). After adjustment, immediate PCI remained an independent predictor of DTB time ≤90 minutes (odds ratio 2.42, 95% confidence interval 1.70 to 3.52, p <0.0001). There were no differences in early and late clinical outcomes. In conclusion, a strategy of transradial direct PCI of the infarct-related artery in selected patients before complete coronary angiography was associated with a benefit of 8 minutes in DTB time. Further study is required to determine whether this strategy can favorably affect clinical outcomes.

Incidence and clinical impact of concurrent chronic total occlusion according to gender in ST-elevation myocardial infarction.

OBJECTIVES: To determine the prevalence of a concurrent CTO in men and women and to examine its impact on mortality. BACKGROUND: The impact of chronic total occlusion (CTO) in patients with ST-elevation myocardial infarction (STEMI) according to gender has not been assessed. METHODS: Patients referred with STEMI were categorized into single vessel disease (SVD), multivessel disease (MVD) without, with 1 or > 1 CTO. The primary end-point was the 1-year mortality. RESULTS: Among the 2020 STEMI patients included between 2006 and 2011, 24% were female. Women were older, had more hypertension and renal failure (P < 0.0001 for all). The prevalence of 1 or > 1 concurrent CTO was similar in both sexes, 7 and 1%, respectively. Early and late mortality was significantly higher in women compared with men (P < 0.0001). In women, the mortality was significantly worse in patients with > 1 CTO (100%) and with 1 CTO (36.4%) compared with those with MVD without CTO (18.4%) or with SVD (10.4%) (P < 0.0001). MVD with and without concurrent CTO were both independent predictors of 1-year mortality in women (HR 3.58; 95 % CI 1.69-7.18 and HR 2.76; 95 % CI 1.33-5.51) whereas only MVD with CTO was predictive in men (HR 2.19; 95% CI 1.20-3.97). CONCLUSIONS: Among unselected STEMI patients, the prevalence of CTO was equal in both sexes whereas early and late mortality remained significantly higher in women. Other factors than the presence of a concurrent CTO must be explored to explain differences in survival after STEMI between women and men.

Deadly association of cardiogenic shock and chronic total occlusion in acute ST-elevation myocardial infarction.

BACKGROUND: The association between cardiogenic shock and 1 or >1 chronic total occlusion (CTO) in unselected patients presenting with ST-elevation myocardial infarction (MI) (STEMI) has not been characterized. METHODS: Patients with STEMI referred with or without cardiogenic shock were categorized into no CTO, 1 CTO, and >1 CTO. The primary end point was the 30-day mortality. RESULTS: Between 2006 and 2011, 2,020 consecutive patients were included. A total of 141 patients (7%) presented with cardiogenic shock on admission. The prevalence of 1 CTO and >1 CTO in a non-infarct-related artery was 23% and 5%, respectively, among patients with shock compared with 6% and 0.5% in patients without shock (P < .0001). Independent predictors of cardiogenic shock included left main-related MI (odds ratio [OR] 6.55, 95% CI 1.39-26.82, P = .019), CTO (OR 4.20, 95% CI 2.64-6.57, P < .001), creatinine clearance <60 mL/min (OR 3.41, 95% CI 2.32-4.99, P < .0001), and left anterior descending-related MI (OR 2.20, 95% CI 1.51-3.23, P < .0001). Thirty-day mortality was 100% in shock patients with >1 CTO, 65.6% with 1 CTO, and 40.2% in patients without CTO (P < .0001). After adjustment for left ventricular ejection fraction and renal function, CTO remained an independent predictor for 30-day mortality (hazard ratio [HR] 1.83; 95% CI 1.10-3.01, P = .02). CONCLUSION: In patients with STEMI, CTO was strongly associated with cardiogenic shock on admission. In this setting, mortality was substantially higher in patients with 1 CTO and exceedingly high in those with >1 CTO. The presence of CTO was an independent predictor of early mortality.

Prevalence, predictors and clinical impact of unique and multiple chronic total occlusion in non-infarct-related artery in patients presenting with ST-elevation myocardial infarction.

OBJECTIVES: To investigate the predictors and impact on long-term survival of one chronic total occlusion (CTO) or multiple CTOs in patients presenting with ST-elevation myocardial infarction (STEMI). DESIGN: Single-centre retrospective observational study. SETTING: University-based tertiary referral centre. PATIENTS: Between 2006 and 2011, a total of 2020 consecutive patients referred with STEMI were categorised into single vessel disease, multivessel disease (MVD) without CTO, with one CTO or with multiple CTOs. INTERVENTION: Primary percutaneous coronary intervention. MAIN OUTCOME MEASURE: The primary end-point was the 1-year mortality. RESULTS: The prevalence of single vessel disease, MVD without CTO, with one CTO or with multiple CTOs was 70%, 22%, 7.2% and 0.8%, respectively. Independent clinical predictors for the presence of CTO were cardiogenic shock (OR 5.05; 95% CI 3.29 to 7.64), prior myocardial infarction (OR 2.06; 95% CI 1.35 to 3.09), age >65 years (OR 1.94; 95% CI 1.40 to 2.71) and history of angina (OR 1.94; 95% CI 1.29 to 2.87). Mortality was worse in patients with multiple CTOs (76.5%) compared with those with one CTO (28.1%) or without CTO (7.3%) (p<0.0001). After adjustment for left ventricular ejection fraction and renal function, MVD was an independent predictor for 1-year mortality (HR: 1.81; 95% CI 1.18 to 2.77, p=0.007), but CTO was not (HR: 1.07; 95% CI 0.66 to 1.73, p=0.78). CONCLUSIONS: Simple clinical factors are associated with the presence of CTO in non-infarct-related artery in patients presenting with STEMI. In these patients, long-term survival was independently associated with MVD, left ventricular ejection fraction and renal function, but not with CTO per se.

A glycine-arginine domain in control of the human MRE11 DNA repair protein.

Human MRE11 is a key enzyme in DNA double-strand break repair and genome stability. Human MRE11 bears a glycine-arginine-rich (GAR) motif that is conserved among multicellular eukaryotic species. We investigated how this motif influences MRE11 function. Human MRE11 alone or a complex of MRE11, RAD50, and NBS1 (MRN) was methylated in insect cells, suggesting that this modification is conserved during evolution. We demonstrate that PRMT1 interacts with MRE11 but not with the MRN complex, suggesting that MRE11 arginine methylation occurs prior to the binding of NBS1 and RAD50. Moreover, the first six methylated arginines are essential for the regulation of MRE11 DNA binding and nuclease activity. The inhibition of arginine methylation leads to a reduction in MRE11 and RAD51 focus formation on a unique double-strand break in vivo. Furthermore, the MRE11-methylated GAR domain is sufficient for its targeting to DNA damage foci and colocalization with gamma-H2AX. These studies highlight an important role for the GAR domain in regulating MRE11 function at the biochemical and cellular levels during DNA double-strand break repair.

PARP1-dependent kinetics of recruitment of MRE11 and NBS1 proteins to multiple DNA damage sites.

Poly(ADP-ribose) polymerase 1 (PARP1) is a nuclear enzyme that is rapidly activated by DNA strand breaks and signals the presence of DNA lesions by attaching ADP-ribose units to chromatin-associated proteins. The therapeutic applications of PARP inhibitors in potentiating the killing action of ionizing radiation have been well documented and are attracting increasing interest as a cancer treatment. However, the initial kinetics underlying the recognition of multiple DNA lesions by PARP1 and how inhibition of PARP potentiates the activity of DNA-damaging agents are unknown. Here we report the spatiotemporal dynamics of PARP1 recruitment to DNA damage induced by laser microirradiation in single living cells. We provide direct evidence that PARP1 is able to accumulate at a locally induced DNA double strand break. Most importantly, we observed that the rapid accumulation of MRE11 and NBS1 at sites of DNA damage requires PARP1. By determining the kinetics of protein assembly following DNA damage, our study reveals the cooperation between PARP1 and the double strand break sensors MRE11 and NBS1 in the close vicinity of a DNA lesion. This may explain the sensitivity of cancer cells to PARP inhibitors.

Stimulation of fission yeast and mouse Hop2-Mnd1 of the Dmc1 and Rad51 recombinases.

Genetic analysis of fission yeast suggests a role for the spHop2-Mnd1 proteins in the Rad51 and Dmc1-dependent meiotic recombination pathways. In order to gain biochemical insights into this process, we purified Schizosaccharomyces pombe Hop2-Mnd1 to homogeneity. spHop2 and spMnd1 interact by co-immunoprecipitation and two-hybrid analysis. Electron microscopy reveals that S. pombe Hop2-Mnd1 binds single-strand DNA ends of 3'-tailed DNA. Interestingly, spHop2-Mnd1 promotes the renaturation of complementary single-strand DNA and catalyses strand exchange reactions with short oligonucleotides. Importantly, we show that spHop2-Mnd1 stimulates spDmc1-dependent strand exchange and strand invasion. Ca(2+) alleviate the requirement for the order of addition of the proteins on DNA. We also demonstrate that while spHop2-Mnd1 affects spDmc1 specifically, mHop2 or mHop2-Mnd1 stimulates both the hRad51 and hDmc1 recombinases in strand exchange assays. Thus, our results suggest a crucial role for S. pombe and mouse Hop2-Mnd1 in homologous pairing and strand exchange and reveal evolutionary divergence in their specificity for the Dmc1 and Rad51 recombinases.

Twists and turns in the function of DNA damage signaling and repair proteins by post-translational modifications.

When the human genome was sequenced, it was surprising to find that it contains approximately 30,000 genes and not 100,000 as most textbooks had predicted. Since then, it became clear that evolution has favored the existence of only a limited number of genes with inducible functions over multiple genes each having specific roles. Many genes products can be modified by post-translational modifications therefore fine-tuning the roles of the corresponding proteins. DNA damage signaling and repair proteins are not an exception to this rule, and they are subject to a wide range of post-translational modifications to orchestrate the DNA damage response. In this review, we will give a comprehensive view of the recent sophisticated mechanisms of DNA damage signal modifications at the nexus of double-strand break DNA damage signaling and repair.

The transcriptional histone acetyltransferase cofactor TRRAP associates with the MRN repair complex and plays a role in DNA double-strand break repair.

Transactivation-transformation domain-associated protein (TRRAP) is a component of several multiprotein histone acetyltransferase (HAT) complexes implicated in transcriptional regulation. TRRAP was shown to be required for the mitotic checkpoint and normal cell cycle progression. MRE11, RAD50, and NBS1 (product of the Nijmegan breakage syndrome gene) form the MRN complex that is involved in the detection, signaling, and repair of DNA double-strand breaks (DSBs). By using double immunopurification, mass spectrometry, and gel filtration, we describe the stable association of TRRAP with the MRN complex. The TRRAP-MRN complex is not associated with any detectable HAT activity, while the isolated other TRRAP complexes, containing either GCN5 or TIP60, are. TRRAP-depleted extracts show a reduced nonhomologous DNA end-joining activity in vitro. Importantly, small interfering RNA knockdown of TRRAP in HeLa cells or TRRAP knockout in mouse embryonic stem cells inhibit the DSB end-joining efficiency and the precise nonhomologous end-joining process, further suggesting a functional involvement of TRRAP in the DSB repair processes. Thus, TRRAP may function as a molecular link between DSB signaling, repair, and chromatin remodeling.

Arginine methylation of MRE11 by PRMT1 is required for DNA damage checkpoint control.

The role of protein arginine methylation in the DNA damage checkpoint response and DNA repair is largely unknown. Herein we show that the MRE11 checkpoint protein is arginine methylated by PRMT1. Mutation of the arginines within MRE11 severely impaired the exonuclease activity of MRE11 but did not influence its ability to form complexes with RAD50 and NBS1. Cells containing hypomethylated MRE11 displayed intra-S-phase DNA damage checkpoint defects that were significantly rescued with the MRE11-RAD50-NBS1 complex. Our results suggest that arginine methylation regulates the activity of MRE11-RAD50-NBS1 complex during the intra-S-phase DNA damage checkpoint response.

Stomach regional specification requires Hoxa5-driven mesenchymal-epithelial signaling.

The genetic control of gut regionalization relies on a hierarchy of molecular events in which the Hox gene family of transcription factors is suspected to be key participant. We have examined the role of Hox genes in gut patterning using the Hoxa5(-/-) mice as a model. Hoxa5 is expressed in a dynamic fashion in the mesenchymal component of the developing gut. Its loss of function results in gastric enzymatic anomalies in Hoxa5(-/-) surviving mutants that are due to perturbed cell specification during stomach development. Histological, biochemical and molecular characterization of the mutant stomach phenotype may be compatible with a homeotic transformation of the gastric mucosa. As the loss of mesenchymal Hoxa5 function leads to gastric epithelial defects, Hoxa5 should exert its action by controlling molecules involved in mesenchymal-epithelial signaling. Indeed, in the absence of Hoxa5 function, the expression of genes encoding for signaling molecules such as sonic hedgehog, Indian hedgehog, transforming growth factor beta family members and fibroblast growth factor 10, is altered. These findings provide insight into the molecular controls of patterning events of the stomach, supporting the notion that Hoxa5 acts in regionalization and specification of the stomach by setting up the proper domains of expression of signaling molecules.