A medical apparatus includes a guidewire and a fixator catheter. The fixator catheter comprises a tubular body with a distal portion and a proximal portion, and further includes a distal opening, a fixator secured to the distal portion, and a body opening arranged between the fixator and the proximal portion. The guidewire passes through the body opening and the distal opening of the fixator catheter. The fixator is movable between a compact configuration and an expanded configuration and, in the expanded condition, is capable of anchoring the guidewire and fixator catheter in a lumen of a blood vessel.