@cherfenn welcome to connect and I am happy that you found us! I also have small vessel heart disease along with widespread Fibromuscular dysplasia, and it is a difficult to road to navigate. I have tried long acting nitro to help control the chest pain with no relief. Nitro sublingual helped the best. My experience is a bit different, I have FMD, but I also have Median Arcuate Ligament syndrome (MALS) that I have had surgical intervention for twice. After my surgery this second time around my chest pain has been under control and I have not needed to take the Nitro, however I have it on hand at all times. Out of curiousity have you been checked fro MALS?