2.2. Literature Search and Study Selection
An initial scoping search and a systematic literature search were performed by a medical librarian to identify RCTs and observational studies that compared concomitant Cox-Maze and PVI in patients who underwent MV surgery. Medline, EMBASE databases, and the Cochrane Library were searched from 1987 up to 15th of March 2022 using the following search terms: Maze surgery, Maze procedure, Maze technique, maze or Cox-Maze vs. pulmonary vein isolation, ablation surgery, ablation procedure, surgical ablation. Details of the search strategy are provided in the Supplement.
We defined 12-month mortality and recurrence of AF postoperatively as outcomes of interest. We expected that variety of outcomes illustrating efficacy/safety would be reported, but they were not reported consistently over the studies.
After deduplication, study eligibility was assessed independently by two investigators. Any discrepancies were resolved by discussion between the 3 investigators. The studies were selected through the following two levels of screening: in the first step studies were independently screened based on titles and abstracts, and in the second step, full-text reports were evaluated based on predefined criteria. Studies were eligible if they compared outcomes in patients with AF undergoing MV surgery and concomitant Cox-Maze procedure or PVI and met the following inclusion criteria:
1. Population: adults or adolescents (12 years or older)
2. Comparator: Cox-Maze vs PVI
3. Provided outcomes: death, recurrence of AF at 12-month follow-up
4. Design: RCT or non-randomized studies of interventions (NRSI) with at least 20 patients per treatment of interest
5. Published in English language.
Studies were ineligible if they had follow-up shorter than 12 months and if they were duplicates. For studies reported in more than one publication, or when institutions reported subsequent studies with accumulating numbers of patients or increased lengths of follow-up, only the most complete reports (in terms of reported outcomes and control of confounding) were included.