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Objective:It remains controversial whether patients with fractional flow reserve (FFR) values of 0.75–0.80 (gray-zone) should be treated with percutaneous coronary intervention (PCI). This study aimed to evaluate the prediction of high-sensitivity C-reactive protein (hs-CRP) levels to guide treatment selection in gray-zone patients.Methods:This prospective interventional trial was conducted between January 2015 and March 2016. A total of 785 patients with stable angina and single-vessel stenosis with moderate coronary lesions were admitted to hospital in this period. After measurement of hs-CRP levels, coronary angiography, and FFR, gray-zone patients (n=308) were included in the study and were divided into four groups on the basis of a cutoff hs-CRP level of 3 mg/L and then on the basis of whether they underwent PCI or not. Patients in groups I (≥3 mg/L, n=70) and III (<3 mg/L, n=84) underwent PCI, whereas those in groups II (≥3 mg/L, n=70) and IV (<3 mg/L, n=84) were administered only drugs. Major adverse clinical events (MACEs) included cardiac death, nonfatal myocardial infarction (MI), target vessel revascularization (TVR), and PCI or coronary artery bypass grafting (CABG). These parameters were also evaluated during follow-up.Results:The total Kaplan-Meier curves showed macrodistribution differences among the four groups (p<0.05). There was a significantly increased MACE incidence in group II compared with group I or IV (p=0.039 or 0.006, respectively), and an increased incidence in group I compared with group III (p=0.028). However, there were no differences in MACE incidence between groups III and IV (p=0.095) despite the fact that these patients received different treatments.Conclusion:Among FFR gray-zone patients, hs-CRP level was a predictor of MACE and risk stratification could guide treatment selection. Increased hs-CRP levels (≥3 mg/L) are an indication for urgent PCI whereas normal levels (<3 mg/L) are an indication for delayed PCI treatment. Patients with identical FFR values could require different treatment.

As a new solid-state welding process, friction stir welding (FSW) has been successfully used for joining low melting point materials such as aluminum and magnesium alloys, but the FSW of high melting point materials such as steels and titanium alloys is still difficult to carry out because of their strict requirements for the FSW tool. Especially for the FSW of titanium alloys, some key technological issues need to solve further. In order to accomplish the FSW of titanium alloys, a specially designed tool system was made. The system was composed of W-Re pin tool, liquid cooling holder and shielding gas shroud. Prior to FSW, the Ti-6Al-4V alloy plates were thermo-hydrogen processed to reduce the deformation resistance and tool wear during the FSW. Based on this, the thermo-hydrogen processed Ti-6Al-4V alloy with different hydrogen content was friction stir welded, and the microstructural characterizations and mechanical properties of the joints were studied. Experimental results showed that the designed tool system can fulfill the requirements of the FSW of titanium alloys, and excellent weld formation and high-strength joint have been obtained from the titanium alloy plates.