Chronic total occlusion crossing devices with imaging

1. An occlusion crossing device comprising:

a rotatable hollow flexible shaft having a central longitudinal axis and an imaging window therein;

an optical fiber extending within the rotatable hollow flexible shaft substantially along the central longitudinal axis of the hollow flexible shaft, a distal tip of the optical fiber aligned with the imaging window so as to transfer an optical coherence tomography signal through the imaging window; and

a cutter attached to a distal end of the hollow flexible shaft.

2. The occlusion crossing device of claim 1 , wherein the optical fiber extends substantially along the central longitudinal axis of the hollow flexible shaft for the entire length of the optical fiber.

3. The occlusion crossing device of claim 1 , further comprising an outer sheath extending around the hollow flexible shaft.

4. The occlusion crossing device of claim 3 , further comprising a monorail guidewire lumen attached to the outer sheath.

5. The occlusion crossing device of claim 3 , wherein the rotatable hollow flexible shaft is configured to rotate within the outer sheath.

6. The occlusion crossing device of claim 3 , wherein the outer sheath is attached to the rotatable hollow flexible shaft.

7. The occlusion crossing device of claim 1 , wherein the cutter further includes a slanted proximal end and a mirror attached to the slanted proximal end, the mirror configured to reflect light from the optical fiber into adjacent tissue.

8. The occlusion crossing device of claim 1 , wherein the optical fiber is attached to the hollow flexible shaft and configured to rotate therewith.

9. The occlusion crossing device of claim 1 , further comprising a handle attached to the rotatable hollow flexible shaft configured to rotate the hollow flexible shaft at speeds of greater than 1,000 rpm.

10. The occlusion crossing device of claim 1 , wherein the occlusion crossing device is less than 0.1 inches in diameter.

11. The occlusion crossing device of claim 1 , wherein the cutter includes a fluted distal end.

12. A method of crossing an occlusion in a blood vessel, the method comprising:

inserting an occlusion crossing device into the blood vessel, the occlusion crossing device including a hollow flexible shaft having a central longitudinal axis and an imaging window therein, an optical fiber extending within the hollow flexible shaft substantially along the central longitudinal axis of the hollow flexible shaft to transfer an optical coherence tomography signal, and a cutter attached to a distal end of the hollow flexible shaft;

rotating the hollow flexible shaft and the cutter so as to separate tissue of the occlusion;

collecting images of the blood vessel through the imaging window with the optical fiber; and

passing the cutter through the occlusion.

13. The method of claim 12 , wherein rotating the hollow flexible shaft and the cutter comprises rotating at speeds of greater than 1,000 rpm.

14. The method of claim 12 , wherein collecting images of the blood vessel comprises collecting the images at rates of greater than 10 frames per minute.

15. The method of claim 12 , further comprising rotating the optical fiber with the hollow flexible shaft.

16. The method of claim 12 , wherein the occlusion crossing device further comprises an outer sheath, and wherein rotating the hollow flexible shaft and the cutter comprises rotating within the outer sheath.

17. The method of claim 12 , wherein the blood vessel is a coronary artery.

18. The method of claim 12 , wherein the blood vessel is a peripheral artery.