A system and apparatus comprising a multisensor guidewire for use in interventional cardiology, e.g. for Transcatheter Valve Therapies (TVT), comprises a plurality of optical sensors for direct measurement of cardiovascular parameters, e.g. transvalvular blood pressure gradients and flow. A conventional outer coil contains a shaped core wire having a cross-section defining helical grooves extending along its length, which accommodate optical fibers and optical sensors within a diameter Dcore of the core wire. Advantageously, the diameter and material of the core wire provides the guidewire with sufficient stiffness for use as a support guidewire for valve replacement, e.g. Transcatheter Aortic Valve Implantation (TAVI), while accommodating multiple sensors and optical fibers within a guidewire of outside diameter ≦0.89 mm. An optical connector couples the guidewire to a control system. Optionally, the guidewire includes a contact force sensor a pre-formed tip and/or a separable micro-connector for proximal mounting of over-the-guidewire components.