Figure 2.

Forest plot of the relative risk (RR) of perioperative mortality after robotic vs. conventional mitral valve surgery. The estimate of the RR of each trial corresponds to the middle of the squares, and the horizontal line shows the 95% confidence interval (CI). On each line, the numbers of events as a fraction of the total number randomized are shown for both treatment groups. For each subgroup, the sum of the statistics, along with the summary RR, is represented by the middle of the solid diamonds. A test of heterogeneity between the trials is given below the summary statistics.