A pressure sensing guidewire, comprising: a) a coiled single filar or multi-filar guidewire forming a lumen, wherein the coil of the guidewire comprises: i) a first coiled frequency providing first openings of a first width between adjacent winds of the coiled single filar or the multi-filars; and ii) at least one second coiled frequency that is less than the first coiled frequency, the second coiled frequency providing at least one second opening of a second width, greater than the first width, between adjacent winds of the coiled single filar or the multi-filars; and b) a fiber optic wire extending through the lumen of the coiled guidewire, the fiber optic wire comprising: a) a fiber core providing an effective refractive index to light having a specific wavelength; b) a first pressure-sensing fiber Bragg grating, FBG, at a first location on the fiber core of the fiber optic wire, wherein the first pressure-sensing FBG is laterally aligned with the at least one second opening of the second width of the coiled single filar or the multi-filars so that the first pressure-sensing FBG is configured for 360° of direct exposure to environmental pressures adjacent thereto. a) a coiled single filar or multi-filar guidewire forming a lumen, wherein the coil of the guidewire comprises: i) a first coiled frequency providing first openings of a first width between adjacent winds of the coiled single filar or the multi-filars; and ii) at least one second coiled frequency that is less than the first coiled frequency, the second coiled frequency providing at least one second opening of a second width, greater than the first width, between adjacent winds of the coiled single filar or the multi-filars; and i) a first coiled frequency providing first openings of a first width between adjacent winds of the coiled single filar or the multi-filars; and ii) at least one second coiled frequency that is less than the first coiled frequency, the second coiled frequency providing at least one second opening of a second width, greater than the first width, between adjacent winds of the coiled single filar or the multi-filars; and b) a fiber optic wire extending through the lumen of the coiled guidewire, the fiber optic wire comprising: a) a fiber core providing an effective refractive index to light having a specific wavelength; b) a first pressure-sensing fiber Bragg grating, FBG, at a first location on the fiber core of the fiber optic wire, wherein the first pressure-sensing FBG is laterally aligned with the at least one second opening of the second width of the coiled single filar or the multi-filars so that the first pressure-sensing FBG is configured for 360° of direct exposure to environmental pressures adjacent thereto. a) a fiber core providing an effective refractive index to light having a specific wavelength; b) a first pressure-sensing fiber Bragg grating, FBG, at a first location on the fiber core of the fiber optic wire, wherein the first pressure-sensing FBG is laterally aligned with the at least one second opening of the second width of the coiled single filar or the multi-filars so that the first pressure-sensing FBG is configured for 360° of direct exposure to environmental pressures adjacent thereto.