Tryptophan, IPA levels tied to lower mortality in coronary artery disease
02 Nov 2022
Levels of indole-3-propionic acid (IPA), a microbiota-produced tryptophan metabolite, and plasma tryptophan appear to contribute to a reduced risk of cardiovascular and all-cause mortality in patients with coronary artery disease (CAD), reveals a prospective study.
A group of researchers sought to determine whether plasma tryptophan and IPA levels correlated with a lower risk of death in 1,829 patients with CAD, whose metabolites were measured using ultra-high performance liquid chromatography.
The associations of tryptophan and IPA levels with the risks of cardiovascular and all-cause mortality were estimated using Cox proportional hazards regression models.
A total of 424 all-cause deaths occurred, with 272 cardiovascular deaths, during a median follow-up of 9.2 years. Plasma tryptophan and IPA levels were found to be significantly related to a lower risk of cardiovascular and all-cause mortality.
CAD patients in the highest quartiles of tryptophan and IPA levels showed multivariable-adjusted hazard ratios of 0.62 (95 percent confidence interval [CI], 0.43‒0.89) and 0.71 (95 percent CI, 0.50‒0.99) for cardiovascular death, respectively, and 0.67 (95 percent CI, 0.50‒0.90) and 0.75 (95 percent CI, 0.57‒0.99) for all-cause death, respectively, relative to those in the lowest quartile.
Multivariable adjustments further revealed that 1-standard deviation increments in the continuous plasma tryptophan and IPA levels correlated with 16-percent and 14-percent reductions in the risk of cardiovascular mortality, respectively, and with 13-percent and 14-percent decreases in the risk of all-cause mortality, respectively.
In addition, linear associations were observed between plasma tryptophan and IPA levels and cardiovascular and all-cause mortality among patients with CAD on restricted cubic splines.
“Further studies are needed to determine the clinical diagnostic and therapeutic values of tryptophan and IPA levels on the risks of mortality among patients with CAD,” the researchers said.