A guide catheter device comprising: an elongate catheter body comprising: a tubular member defining a lumen and an outer surface, the tubular member comprising a metallic helical coil (206a, 206b, 206c) defining a plurality of winds separated by gaps and a polymeric material (207a, 207b) disposed within the gaps, wherein the metallic helical coil (206a, 206b, 206c) includes a proximal coil portion and a distal coil portion, the distal coil portion (31 0) being positioned between the proximal coil portion and a distal end of the catheter body, the gaps in the distal coil portion each having a width in a range of 0.152 mm (0.006 inches) to 0.25 mm (0.010 inches), and the gaps in the proximal coil portion each having a width in a range of 0.013 mm (0.0005 inches) to 0.051 mm (0.002 inches); an inner liner extending through the lumen of the tubular member and defining an inner lumen of the catheter; and an outer tubular cover (108, 109, 208, 209) on the outer surface of the tubular member, wherein the tubular member comprises a proximal segment and a distal segment, wherein the proximal segment is stiffer than the distal segment, and wherein the polymeric material disposed within the gaps is different from the materials of the inner liner and the outer tubular cover, and wherein the catheter body has an inner diameter to wall thickness ratio of 16:1 to 24: 1. an elongate catheter body comprising: a tubular member defining a lumen and an outer surface, the tubular member comprising a metallic helical coil (206a, 206b, 206c) defining a plurality of winds separated by gaps and a polymeric material (207a, 207b) disposed within the gaps, wherein the metallic helical coil (206a, 206b, 206c) includes a proximal coil portion and a distal coil portion, the distal coil portion (31 0) being positioned between the proximal coil portion and a distal end of the catheter body, the gaps in the distal coil portion each having a width in a range of 0.152 mm (0.006 inches) to 0.25 mm (0.010 inches), and the gaps in the proximal coil portion each having a width in a range of 0.013 mm (0.0005 inches) to 0.051 mm (0.002 inches); an inner liner extending through the lumen of the tubular member and defining an inner lumen of the catheter; and an outer tubular cover (108, 109, 208, 209) on the outer surface of the tubular member, a tubular member defining a lumen and an outer surface, the tubular member comprising a metallic helical coil (206a, 206b, 206c) defining a plurality of winds separated by gaps and a polymeric material (207a, 207b) disposed within the gaps, wherein the metallic helical coil (206a, 206b, 206c) includes a proximal coil portion and a distal coil portion, the distal coil portion (31 0) being positioned between the proximal coil portion and a distal end of the catheter body, the gaps in the distal coil portion each having a width in a range of 0.152 mm (0.006 inches) to 0.25 mm (0.010 inches), and the gaps in the proximal coil portion each having a width in a range of 0.013 mm (0.0005 inches) to 0.051 mm (0.002 inches); an inner liner extending through the lumen of the tubular member and defining an inner lumen of the catheter; and an outer tubular cover (108, 109, 208, 209) on the outer surface of the tubular member, wherein the tubular member comprises a proximal segment and a distal segment, wherein the proximal segment is stiffer than the distal segment, and wherein the polymeric material disposed within the gaps is different from the materials of the inner liner and the outer tubular cover, and wherein the catheter body has an inner diameter to wall thickness ratio of 16:1 to 24: 1.