Abstract: A vascular interventional device may be introduced over a guidewire into a vessel of the cardiovascular system of a patient. This device includes a hollow, flexible tube having a proximal end and a distal end that is adapted to selectively engage a target vessel of the cardiovascular system of the patient. This tube also includes a lumen that is continuous from the proximal to the distal end, and has an end hole in the distal end that is in fluid communication with the lumen. A plurality of side holes are provided near the distal end of the tube, each of which is in continuous fluid communication with the lumen. The device also includes a hollow vessel dilator that is adapted for insertion into and through the tube and over the guidewire. The dilator has an inside diameter that is slightly larger than the guidewire and an outside diameter that is slightly smaller than the diameter of the lumen of the tube.