A tortuous aorta indicates the vessel is abnormally twisted, bent, etc. rather than a good open channel that does not hinder the blood flow. There would be some obstruction to blood flow, and depending on the degree of resistance the heart pumps against would be the factor for seriousness.
If serious, there can be reduced blood flow to the system, increased blood pressure, enlarged heart chambers. Tortuous aorta has also been implicated in some cases of pain caused by a displaced esophagus, as the twistings of the vessel can actually push the esophagus out of position.
Unless the condition causes issues there may not be of much significance. However, if there are symptoms present, it is more likely that the tortuous aorta is harmful and your physician may recommend surgery to correct the abnormality.