The chip formation mechanism during precision cutting of metallic glass (Zr55Cu30Ni5Al10 at%) was investigated around the glass transition temperature (673 K). Orthogonal cutting of metallic glass ...are conducted on a fly-cutting machine at various cutting speeds. The new surface of the chips was slightly shiny while the free surface exhibited lamellar slip structure. The cutting temperature was a proportional to the cutting ratio and chip shear angle. The surface integrity worsened with an increased flow of cutting chip due to an increase in the cutting speed. An increase in the cutting temperature caused the chips formation to change from flow type chips to discontinuous chips. When the cutting speed exceeded 300 m/min, the shear angle increased while the shear pitch of the chips decreased. It appears that when the cutting temperature exceeded the glass transition temperature, the strength of the metallic glass decreased and the ductility mode changed due to viscous flow.
ObjectiveThis study aims to investigate the time-dependent prognostic utility of two fibrosis markers representing organ fibrogenesis (N-terminal propeptide of procollagen III (PIIINP) and type IV ...collagen 7S (P4NP 7S)) in patients with acute heart failure (HF).Methods390 patients with acute HF were dichotomised based on the median value of fibrosis markers at discharge. The primary outcome measure was a composite of cardiac death and HF hospitalisation.ResultsP4NP 7S significantly declined during hospitalisation, whereas PIIINP did not. The cumulative 90-day and 365-day incidence of the primary outcome measure was 16.6% vs 16.0% (p=0.42) and 33.3% vs 28.4% (p=0.34) in the patients with high versus low PIIINP; 19.9% vs 13.0% (p=0.04) and 32.3% vs 29.0% (p=0.34) in the patients with high and low P4NP 7S, respectively. After adjusting for confounders, high P4NP 7S correlated with significant excess risk relative to low P4NP 7S for both 90-day and 365-day primary outcome measure (adjusted HR, 1.50; 95% CI, 1.02 to 2.21; p=0.04 and adjusted HR, 1.89; 95% CI, 1.11 to 3.26; p=0.02, respectively), which was driven by significant association of high P4NP 7S with higher incidence of HF hospitalisation. Furthermore, P4NP 7S exhibited an additive value to conventional prognostic factors for predicting 90-day outcome (p=0.038 for net reclassification improvement; p=0.0068 for integrated discrimination improvement). High PIIINP did not correlate with significant excess risk for both 90-day and 365-day outcome.ConclusionsThis study suggests a possible role of P4NP 7S in the risk stratification of patients with acute HF.
Two randomized control trials demonstrated that transcatheter aortic valve implantation was associated with 1–2 year clinical outcomes comparable or even superior to surgical aortic valve replacement ...(SAVR) in low surgical risk patients with severe aortic stenosis (AS). However, no previous study has reported the clinical outcomes after SAVR in Japanese patients with low surgical risk. From 3815 consecutive patients enrolled in the CURRENT AS registry, we retrieved 220 patients who underwent SAVR in reference to the inclusion and exclusion criteria of the PARTNER 3 trial. Age and surgical risk score in the current study population were comparable to those in the PARTNER 3 trial (Age: 75 years versus 74 years, and STS-PROM score: 2.3 versus 1.9). The cumulative incidence of a composite all-cause death or stroke was comparable between the current study population and the SAVR patients in the PARTNER 3 trial both at 30-day (2.3% versus 3.3%), and at 1-year (4.1% versus 4.9%). The clinical outcomes of SAVR in low surgical risk patients with severe AS selected from a real world Japanese registry according to the inclusion and exclusion criteria of the PARTNER 3 trial was favorable and numerically comparable to those of SAVR patients in the PARTNER 3 trial.
One-month duration of dual antiplatelet therapy (DAPT) has widely been adopted after bare-metal stent (BMS) implantation in the real clinical practice. However, it has not been adequately addressed ...yet whether DAPT for only 1-month could provide sufficient protection from ischemic events beyond 1-month after BMS implantation. We assessed the effects of short DAPT relative to prolonged DAPT on clinical outcomes with the landmark analysis at 2 month after BMS implantation. Among 13,058 consecutive patients enrolled in the CREDO-Kyoto registry cohort-2, this study population consisted of 4905 patients treated with BMS only in whom the information on the status of antiplatelet therapy was available at 2 month after stent implantation single-antiplatelet therapy (SAPT) group:
N
= 2575 (acute myocardial infarction (AMI):
N
= 1257, and non-AMI:
N
= 1318), and DAPT group:
N
= 2330 (AMI:
N
= 1304, and non-AMI:
N
= 1026). Cumulative 3-year incidence of the primary outcome measure (a composite of cardiovascular death, myocardial infarction, stroke, definite stent thrombosis, and GUSTO moderate/severe bleeding) was not significantly different between the SAPT and DAPT groups (9.8 versus 10.6 %,
P
= 0.34). After adjusting confounders, the risk of SAPT relative to DAPT for the primary outcome measure remained insignificant in the entire cohort (HR 0.97, 95 % CI 0.79–1.19,
P
= 0.77), and in both AMI and non-AMI strata without any significant interaction between clinical presentation (AMI versus non-AMI) and the effect of SAPT relative to DAPT (P interaction = 0.56). In conclusion, short DAPT <2 month after BMS implantation was as safe as prolonged DAPT ≥2-month in both AMI and non-AMI patients.
Hemodynamic disturbance in heart failure (HF) induces extra-cardiac organ injury. Atrial fibrillation (AF) is common in patients with HF. The relationship between AF and organ injury in HF remains ...unclear. We investigated the relationship between AF and the liver fibrosis marker, type IV collagen 7S (P4NP 7S) in patients with HF.
From a pooled dataset of 3 observational cohorts of hospitalized HF, 720 patients in whom P4NP 7S was measured before discharge were included. Median P4NP 7S were 5.1, 5.3, and 6.2 ng/mL in the sinus rhythm (SR) (n = 368), paroxysmal AF (n = 67), and persistent AF (n = 285) groups, respectively (P < 0.001). In the multiple linear regression analysis, the significant association with P4NP 7S was found for persistent AF (P < 0.001). The cumulative 1-year incidence of the primary composite endpoint of cardiac death and HF hospitalization were 27.6, 24.1, and 34.5% in the SR, paroxysmal AF, and persistent AF groups, respectively (Log-rank P = 0.07) and 25.3 and 34.5% in the low (below median) and high P4NP 7S groups, respectively (Log-rank P = 0.005). The adjusted risks of persistent AF versus SR and high P4NP 7S versus low P4NP 7S for the primary endpoint were 1.38 (95% confidence interval 1.02–1.89) and 1.52 (1.14–2.03), respectively. When patients were divided based on a combination of AF and P4NP 7S, concomitant persistent AF and high P4NP 7S portended a dismal prognosis.
AF is associated with an increase in the liver fibrosis marker. Co-presence of persistent AF and P4NP 7S may portend adverse clinical outcomes.
•Persistent atrial fibrillation (AF) was associated with an increased liver fibrosis.•Both persistent AF and high type IV collagen 7S (P4NP 7S) portends adverse outcomes.•Concomitant high P4NP 7S and persistent AF portends very poor prognosis.•P4NP 7S may facilitate the risk stratification of patients with persistent AF.
Due to serious concerns on very late stent thrombosis (VLST), extended use of dual antiplatelet therapy (DAPT) beyond 1 year after DES implantation has become a common clinical practice despite ...apparent lack of evidence suggesting its efficacy in reducing VLST. The study population consisted of 12812 patients in the j-Cypher registry who were treated with at least one sirolimus-eluting stent (SES). We assessed the relation between duration of thienopyridine therapy and clinical outcomes with a landmark analysis at 1 year after SES implantation. Among 11713 patients without myocardial infarction (MI), stent thrombosis and stroke at 1 year who were eligible for the landmark analysis, 7414 patients (63 %) were maintained on thienopyridine at 1-year landmark point, while 4299 patients (37 %) had discontinued thienopyridine before 1-year landmark point. Patients in the on-thienopyridine group had more complex characteristics than patients in the off-thienopyridine group. Cumulative incidence of and the risk for definite VLST in the on-thienopyridine group relative to the off-thienopyridine group favored prolonged DAPT, but were not significant 0.9 and 1.2 %,
P
= 0.1, and adjusted HR (95 % CI): 0.71 (0.47–1.06),
P
= 0.11. Cumulative incidence of and the risk for a composite of death, MI, or stroke in the on-thienopyridine group relative to the off-thienopyridine group were also not significant 15.3 and 14.3 %,
P
= 0.15, and adjusted HR (95 % CI): 0.99 (0.89–1.11),
P
= 0.89. Prolonged use of thienopyridine beyond 1 year after SES implantation was not associated with significant decrease in the risks for VLST or for serious cardiovascular events including death, MI or stroke.
Abstract Background Current guidelines generally recommend watchful waiting until symptoms emerge for aortic valve replacement (AVR) in asymptomatic patients with severe aortic stenosis (AS). ...Objectives The study sought to compare the long-term outcomes of initial AVR versus conservative strategies following the diagnosis of asymptomatic severe AS. Methods We used data from a large multicenter registry enrolling 3,815 consecutive patients with severe AS (peak aortic jet velocity >4.0 m/s, or mean aortic pressure gradient >40 mm Hg, or aortic valve area <1.0 cm2 ) between January 2003 and December 2011. Among 1,808 asymptomatic patients, the initial AVR and conservative strategies were chosen in 291 patients, and 1,517 patients, respectively. Median follow-up was 1,361 days with 90% follow-up rate at 2 years. The propensity score–matched cohort of 582 patients (n = 291 in each group) was developed as the main analysis set for the current report. Results Baseline characteristics of the propensity score–matched cohort were largely comparable, except for the slightly younger age and the greater AS severity in the initial AVR group. In the conservative group, AVR was performed in 41% of patients during follow-up. The cumulative 5-year incidences of all-cause death and heart failure hospitalization were significantly lower in the initial AVR group than in the conservative group (15.4% vs. 26.4%, p = 0.009; 3.8% vs. 19.9%, p < 0.001, respectively). Conclusions The long-term outcome of asymptomatic patients with severe AS was dismal when managed conservatively in this real-world analysis and might be substantially improved by an initial AVR strategy. (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis Registry; UMIN000012140 )
The benefits of long-term oral β-blocker therapy in patients with ST-segment elevation myocardial infarction (STEMI) with mildly reduced left ventricular ejection fraction (LVEF; ≥40%) are still ...unknown. We sought to evaluate the efficacy of β-blocker therapy in patients with STEMI with mildly reduced LVEF. In the CAPITAL-RCT (Carvedilol Post-Intervention Long-Term Administration in Large-Scale Randomized Controlled Trial), patients with STEMI with successful percutaneous coronary intervention with an LVEF of ≥40% were randomly assigned to carvedilol or no β-blocker therapy. Among 794 patients, 280 patients had an LVEF of <55% at baseline (mildly reduced LVEF stratum), whereas 514 patients had an LVEF of ≥55% at baseline (normal LVEF stratum). The primary end point was a composite of all-cause death, myocardial infarction, hospitalization for acute coronary syndrome, and hospitalization for heart failure, and the secondary end point was a cardiac composite outcome: a composite of cardiac death, myocardial infarction, and hospitalization for heart failure. The median follow-up period was 3.7 years. The lower risk of carvedilol therapy relative to no β-blocker therapy was not significant for the primary end point in either the mildly reduced or normal LVEF strata. However, it was significant for the cardiac composite end point in the mildly reduced LVEF stratum (0.82/100 person-years vs 2.59/100 person-years, hazard ratio 0.32 0.10 to 0.99, p = 0.047) but not in the normal LVEF stratum (1.48/100 person-years vs 1.06/100 person-years, hazard ratio 1.39 0.62 to 3.13, p = 0.43, p for interaction = 0.04). In conclusion, long-term carvedilol therapy in patients with STEMI with primary percutaneous coronary intervention might be beneficial for preventing cardiac-related events in those with a mildly reduced LVEF.
Clopidogrel monotherapy after short dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) has not yet been fully investigated in patients with acute coronary syndrome (ACS).
...To test the hypothesis of noninferiority of 1 to 2 months of DAPT compared with 12 months of DAPT for a composite end point of cardiovascular and bleeding events in patients with ACS.
This multicenter, open-label, randomized clinical trial enrolled 4169 patients with ACS who underwent successful PCI using cobalt-chromium everolimus-eluting stents at 96 centers in Japan from December 2015 through June 2020. These data were analyzed from June to July 2021.
Patients were randomized either to 1 to 2 months of DAPT followed by clopidogrel monotherapy (n = 2078) or to 12 months of DAPT with aspirin and clopidogrel (n = 2091).
The primary end point was a composite of cardiovascular (cardiovascular death, myocardial infarction MI, any stroke, or definite stent thrombosis) or bleeding (Thrombolysis in MI major or minor bleeding) events at 12 months, with a noninferiority margin of 50% on the hazard ratio (HR) scale. The major secondary end points were cardiovascular and bleeding components of the primary end point.
Among 4169 randomized patients, 33 withdrew consent. Of the 4136 included patients, the mean (SD) age was 66.8 (11.9) years, and 856 (21%) were women, 2324 (56%) had ST-segment elevation MI, and 826 (20%) had non-ST-segment elevation MI. A total of 4107 patients (99.3%) completed the 1-year follow-up in June 2021. One to 2 months of DAPT was not noninferior to 12 months of DAPT for the primary end point, which occurred in 65 of 2058 patients (3.2%) in the 1- to 2-month DAPT group and in 58 of 2057 patients (2.8%) in the 12-month DAPT group (absolute difference, 0.37% 95% CI, -0.68% to 1.42%; HR, 1.14 95% CI, 0.80-1.62; P for noninferiority = .06). The major secondary cardiovascular end point occurred in 56 patients (2.8%) in the 1- to 2-month DAPT group and in 38 patients (1.9%) in the 12-month DAPT group (absolute difference, 0.90% 95% CI, -0.02% to 1.82%; HR, 1.50 95% CI, 0.99-2.26). The major secondary bleeding end point occurred in 11 patients (0.5%) in the 1- to 2-month DAPT group and 24 patients (1.2%) in the 12-month DAPT group (absolute difference, -0.63% 95% CI, -1.20% to -0.06%; HR, 0.46 95% CI, 0.23-0.94).
In patients with ACS with successful PCI, clopidogrel monotherapy after 1 to 2 months of DAPT failed to attest noninferiority to standard 12 months of DAPT for the net clinical benefit with a numerical increase in cardiovascular events despite reduction in bleeding events. The directionally different efficacy and safety outcomes indicate the need for further clinical trials.
ClinicalTrials.gov Identifiers: NCT02619760 and NCT03462498.
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