[A prospective study on the safety and efficacy of excimer laser coronary angioplasty for the treatment of degenerated great saphenous vein graft]

Objective: To explore the safety and efficacy of excimer laser coronary angioplasty (ELCA) for the treatment of degenerated great saphenous vein graft (SVG). Methods: This is a single-center, prospective, single-arm study. Patients, who were admitted to the Geriatric Cardiovascular Center of Beijing Anzhen Hospital from January 2022 to June 2022, were consecutively enrolled. Inclusion criteria were recurrent chest pain after coronary artery bypass surgery (CABG), and coronary angiography confirmed that the SVG stenosis was more than 70% but not completely occluded, and interventional treatment for SVG lesions was planned. Before balloon dilation and stent placement, ELCA was used to pretreat the lesions. Optical coherence tomography (OCT) examination was performed and postoperative index of microcirculation resistance (IMR) were assessed after stent implantation. The technique success rate and operation success rate were calculated. The technique success was defined as the successful passage of the ELCA system through the lesion. Operation success was defined as the successful placement of a stent at the lesion. The primary evaluation index of the study was IMR immediately after PCI. Secondary evaluation indexes included thrombolysis in myocardial infarction (TIMI) flow grade, corrected TIMI frame count (cTFC), minimal stent area and stent expansion measured by OCT after PCI, and procedural complications (Ⅳa myocardial infarction, no reflow, perforation). Results: A total of 19 patients aged (66.0±5.6) years were enrolled, including 18 males (94.7%). The age of SVG was 8 (6, 11) years. The length of the lesions was greater than 20 mm, and they were all SVG body lesions. The median stenosis degree was 95% (80%, 99%), and the length of the implanted stent was (41.7±16.3)mm. The operation time was 119 (101, 166) minutes, and the cumulative dose was 2 089 (1 378, 3 011)mGy. The diameter of the laser catheter was 1.4 mm, the maximum energy was 60 mJ, and the maximum frequency was 40 Hz. The technique success and the operation success rate were both 100% (19/19). The IMR after stent implantation was 29.22±5.95. The TIMI flow grade of patients after ELCA and stent implantation was significantly improved (all P>0.05), and the TIMI flow grade of all patients after stent implantation was Grade Ⅲ. The cTFC decreased significantly after ELCA (33.2±7.8) and after stent placement (22.8±7.1) than preoperative level (49.7±13.0) (both P<0.001). The minimum stent area was (5.53±1.36)mm², and the stent expansion rate was (90.0±4.3)%. Perforation, no reflow, type Ⅳa myocardial infarction and other complications were not observed. However, postoperative high-sensitivity troponin level was significantly increased ((67.937±33.839)ng/L vs. (5.316±3.105)ng/L, P<0.001). Conclusion: ELCA is safe and effective in the treatment of SVG lesions and could improve microcirculation and ensure full expansion of stent.

[Relationship between plasma miR-126 and coronary slow flow phenomenon]

Objective: To investigate the relationship between miR-126 in plasma and coronary slow flow (CSF) phenomenon. Methods: A total of 109 patients without coronary artery disease who underwent coronary angiography at Beijing Anzhen Hospital Affiliated to Capital Medical University from August 2016 to March 2018 were enrolled. The patients were divided into CSF groups (53 cases) and the control group (56 cases) according to CSF existing or not. Clinical data and blood samples of the participants in two groups were collected. Real-time quantitative PCR (RT-qPCR) was used to determine the expression of miR-126 in plasma, and the relationship between miR-126 and CSF and its predictive effect were analyzed. Results: Mean TIMI frame counts (34±4 vs 20±3), left anterior descending TIMI frame counts (35±5 vs 21±3), left gyroscopic TIMI frame counts (36±5 vs 20±3), right coronary TIMI frame counts (34±5 vs 20±35) and expression level of hypersensitive C-reactive protein (hs-CRP, (3.0±1.2) mg/L vs (2.1±0.9) mg/L) and plasma miR-126 (0.25±0.09 vs 0.19±0.10) of the CSF group were significantly higher than those of the control group (P<0.05). Correlation analysis showed that miR-126 and hs-CRP levels were significantly correlated with mean TIMI frame count (r=0.367, P<0.05), and miR-126 was also significantly associated with the hs-CRP level (r=0.388, P<0.05). Logistic regression analysis showed that miR-126 (OR=2.513) and hs-CRP (OR=1.568) were independent risk factors for coronary slow flow. The area under the ROC curve of miR-126 predicting for CSF was 0.661. When the cutoff value was set at 0.225, the Youden index reached the maximum with a sensitivity of 0.660 and a specificity of 0.714. Conclusion: The expression level of miR-126 in plasma is significantly correlated with CSF, and miR-126 can be used as a predictor of coronary slow flow phenomenon.

Focus on phosphohistidine

Phosphohistidine has been identified as an enzymic intermediate in numerous biochemical reactions and plays a functional role in many regulatory pathways. Unlike the phosphoester bond of its cousins (phosphoserine, phosphothreonine and phosphotyrosine), the phosphoramidate (P-N) bond of phosphohistidine has a high DeltaG degrees of hydrolysis and is unstable under acidic conditions. This acid-lability has meant that the study of protein histidine phosphorylation and the associated protein kinases has been slower to progress than other protein phosphorylation studies. Histidine phosphorylation is a crucial component of cell signalling in prokaryotes and lower eukaryotes. It is also now becoming widely reported in mammalian signalling pathways and implicated in certain human disease states. This review covers the chemistry of phosphohistidine in terms of its isomeric forms and chemical derivatives, how they can be synthesized, purified, identified and the relative stabilities of each of these forms. Furthermore, we highlight how this chemistry relates to the role of phosphohistidine in its various biological functions.