I’m learning about time-dependent coefficients in R using the material below.
https://cran.r-project.org/web/packages/survival/vignettes/timedep.pdf

In 3.4 PBC data, the code below correctly assumes the hazard associated with changing bili and protime values.

fit2 <- coxph(Surv(tstart, tstop, death==2) ~ log(bili) + log(protime), pbc2)

My question is, how can you expand this analysis to predict survival after liver transplant using pre-transplant bilirubin and protime values?
(Not comparing transplant vs no transplant (medical treatment) as explained in the YouTube video: https://www.youtube.com/watch?v=Lbqdvn7YHh4)

This is not compatible with pbc/pbcseq database, but assume all patients who died in pbc/pbcseq database receive liver transplant at death date (status = 0 or 1 only), and we also have post-liver transplant survival data, as in jasa dataset depicted in 3.3.

Is it possible with R?