Patients’ selection
We retrospectively studied consecutive 150 long-persistent or persistent AF patients who required to undergoing the cryoMaze procedures combined with valve-surgery at the department of cardiovascular surgery, General Hospital of Northern Theatre Command, from 2015 to 2018. Exclusion criteria were (1) emergency surgery; (2) combined with CABG or any other heart procedures; (3) previous cardiovascular surgery; (4) primary pulmonary hypertension; (5) EF<0.40, and (6) history of cerebral hemorrhage or brain stoke within 3 months. Of these, 122 (81.3%) had baseline complete blood counts necessary for the inflammatory indexes and all clinical data available and were considered fully evaluable for this post hoc analysis.
This study was approved by the General Hospital of Northern Theatre Command’s Ethics committee. All procedures were performed by the Declaration of Helsinki and its later amendments or comparable ethical standards.
Surgical procedure, ablation procedure, post-operative management, and follow-up
Surgical procedure, ablation procedure, post-operative management and follow-up have been described before.[5] Briefly, after cardioplegic arrest and aortic cross-clamping, the left lesion sets and concomitant operations were performed. The lesion sets of the CryoMaze were created using cryothermia based on Nitrous Oxide (Atricure CRYO2 Cryosurgical probe, –60°C, 2min). The detail of lesion sets and ablation procedure could be found before.[5]
Heart rhythm was monitored continuously throughout the hospital stay, and temporary epicardial wires were used for ventricular pacing as needed in all the patients after the surgery. Amiodarone was given intravenously from 20 to 40 mg/h, followed by oral amiodarone at 200 mg twice a day and then 200 mg/day until 3 months after discharge. According to the 24-hour Holter results at 3 months, amiodarone was withdrawn for patients restore to sinus rhythm. Amiodarone was continually administered in AF patients. Electrical cardioversion was applied in patients when oral amiodarone failed to maintain sinus rhythm. After discharge, patients were followed up at outpatient clinic at 1,3, 6, and 12 months. Heart rhythm was verified with 24-hour Holter monitoring and echocardiography were evaluated by 2-dimensional echocardiographic analysis and Doppler color flow imaging (Philips iE33 ultrasound machine; Philips Healthcare, Andover, Mass) at each visit.[5] The definition of atrial tachyarrhythmia recurrence was any documented AF, atrial flutter, or atrial tachyarrhythmia lasting ≥30 seconds after three months blanking period.[15]
Post hoc analysis variable definitions
For this post hoc analysis, the inflammatory indexes were determined based on values of monocytes (M), neutrophils (N), lymphocytes (L), and/or platelets (P) in patients received surgical ablation at indicated data: SII defined as P×N/L, NLR defined as N/L, platelet-lymphocyte ratio (PLR) defined as P/L, lymphocyte to monocyte ratio (LMR) defined as L/M, monocytes-NLR (MNLR) defined as M×N/L, monocytes-PLR (MPLR) defined as M×P/L .[14, 16, 17]
Statistical analysis
The IBM SPSS.24.0 software was used for all dates analyzed. Continuous variables were presented as Mean± SD or medians (range). And the categorical variables were described as frequencies and percentages. To compare the differences between two groups, the independent student’s t text and mann-whitney U text were used. chi-squared test or Fisher’s exact test were used for categorical variables. Risk factors that p <0.05 were included in the Univariate logistic regression analysis. p <0.05 was considered significant in all comparisons.