**6. Conclusions**

The potent toll to halt inflammatory response has been given to rheumatologists and immunologists. So far, JAK inhibitors showed a high level of efficacy and satisfactorily level of safety. As with all novel compounds many questions arise regarding the safety profile and potential influence of these drugs on the functioning of vitally important internal organs, including the cardiovascular system. With the small synthetic compounds, we may block many cytokines belonging to several families, which exert both pro- and anti-inflammatory potentials. Parallel to this, we may change the expression of hundreds of related genes, creating a new environment for our patients. At the current level of knowledge, the direct influence of JAK inhibitors on the cardiovascular system is neutral or slightly beneficial. As we still accumulate knowledge on this impact, currently available data regarding this influence are not yet conclusive and more studies in this field are required. At this moment, it is still unclear which mechanisms may drive thromboembolic risk and this is the main concern regarding the administration of JAK inhibitors in patients with RA.

**Author Contributions:** Conceived and designed: P.J.K. and M.A.I.; wrote the original draft: P.J.K.; edited, critically reviewed, and revised the manuscript: M.A.I. and M.E.; drew figures: M.A.I. All authors have read and agreed to the published version of the manuscript.

**Funding:** This paper was funded by Medical University of Silesia, Katowice Poland.

**Conflicts of Interest:** The authors declare no conflict of interest.
