LVRS survival curves

Kaplan-Meier estimates of the cumulative probability of death as a function of years after randomization to LVRS (red line) or medical treatment (blue line) for (A) all patients in the National Emphysema Treatment Trial and (B-D) non-high-risk and upper-lobe-predominant emphysema subgroups of patients:
(A) All patients (n = 1218).
(B) Non-high-risk patients (n = 1078).
(C) Upper-lobe-predominant and low baseline exercise capacity (n = 290).
(D) Upper-lobe-predominant and high exercise capacity (n = 419).
The p value is from the Fisher exact test for difference in the proportions of patients who died during the 4.3 years (median) of follow-up.