Abstract: A catheter for use in vasculature or other lumens within body structures includes a shaft formed from an elongated polymeric flexible tube. A thin polymeric sleeve is placed over a proximal portion of the catheter shaft. A hub structure is injection molded over the sleeve with a polymer of the same type as the polymeric sleeve. The heat from the injection molded polymer of the hub body is sufficient to heat the polymeric sleeve, causing the polymeric sleeve to bond the hub body to the sleeve, and the sleeve to the catheter shaft. In this way, the injection molded polymeric hub structure is fused to the catheter shaft, with a unified polymeric bond, and without the use of adhesive. The plastic sleeve is sufficiently thick to protect the catheter shaft from the heat of the injection molded molten polymer while still allowing the catheter shaft and sleeve to bond to the shaft.