Sensors for catheter pumps
Sensors for catheter pumps are disclosed herein. The catheter pump can include a catheter assembly comprising a catheter and a cannula coupled to a distal portion of the catheter. The cannula can have a proximal port for permitting the flow of blood therethrough. The catheter assembly can include a sensor to be disposed near the proximal port. A processing unit can be programmed to process a signal detected by the sensor. The processing unit can comprise a computer-readable set of rules to evaluate the signal to determine a position of the cannula relative to an aortic valve of a patient.
1. A method of pumping blood through a patient, the method comprising:
inserting a catheter pump into the patient, the catheter pump comprising a catheter body, a cannula coupled with the catheter body, an impeller within the cannula, a sensor assembly near the impeller, and a sheath disposed about the catheter body;
providing relative motion between the sheath and the sensor assembly to expose the sensor assembly to the blood;
rotating the impeller; and
measuring a pressure of the blood with the exposed sensor assembly.
2. The method of claim 1 , wherein providing relative motion comprises sliding the sheath proximally relative to the cannula and the sensor assembly.
3. The method of claim 2 , wherein the cannula and impeller expand to deployed configurations upon sliding the sheath proximally.
4. The method of claim 1 , wherein the sensor assembly is disposed proximal the impeller, the method comprising sliding the sheath until a sensor element is exposed through a window of the catheter pump.
5. The method of claim 1 , wherein the sensor assembly is disposed on a wall of the cannula, the method comprising sliding the sheath until a sensor element is exposed to the blood.
6. The method of claim 1 , wherein the sensor assembly is disposed in a central lumen of the catheter pump that extends distal the impeller, the method comprising sliding the sheath until a sensor element is exposed through an opening or window in the central lumen.
7. A method of pumping blood through a patient, the method comprising:
advancing an impeller assembly through a vascular system of the patient to a left ventricle of the patient, the impeller assembly comprising an impeller and a sensor, the sensor configured to measure a pressure of blood flowing through one or more inlets of the impeller assembly;
activating the impeller to pump blood through an aorta of the patient at a flow rate of at least about 2 liters per minute (Lpm); and
maintaining an average pressure of less than about 15 mmHg in the left ventricle of the patient.
8. The method of claim 7 , wherein activating the impeller comprises activating the impeller to pump blood through the aorta at a flow rate of at least about 4 Lpm.
9. The method of claim 7 , wherein activating the impeller comprises activating the impeller to pump blood through the aorta at a flow rate of at least about 5 Lpm.
10. The method of claim 7 , wherein activating the impeller comprises activating the impeller to pump blood through the aorta at a flow rate in a range of about 4 Lpm to about 5.5 Lpm.
11. The method of claim 7 , wherein activating the impeller comprises activating the impeller to pump blood through the aorta in a range of about 4.5 Lpm to about 5.5 Lpm.
12. The method of claim 7 , wherein maintaining the average pressure comprises maintaining an average pressure of less than about 10 mmHg in the left ventricle of the patient.
13. The method of claim 12 , wherein maintaining the average pressure comprises maintaining an average pressure of less than about 5 mmHg in the left ventricle of the patient.
14. The method of claim 12 , wherein maintaining the average pressure comprises maintaining a pressure in a range of about 2 mmHg to about 8 mmHg.
15. The method of claim 14 , wherein maintaining the pressure comprises maintaining a pressure in a range of about 3 mmHg to about 6 mmHg.
16. The method of claim 15 , wherein maintaining the pressure comprises maintaining a pressure in a range of about 4 mmHg to about 5 mmHg.
17. The method of claim 7 , wherein advancing the impeller assembly comprises advancing a distal portion of the impeller assembly past the aortic valve until the inlet(s) of the cannula are distal the aortic valve by a distance in a range of about 0.5 cm to about 4 cm.
18. The method of claim 17 , wherein advancing the impeller assembly comprises advancing the distal portion of the impeller assembly past the aortic valve until the inlet(s) of the cannula are distal the aortic valve by a distance in a range of about 1.5 cm to about 3 cm.
19. The method of claim 7 further comprising:
monitoring the pressure in the left ventricle of the patient based at least in part on a signal representative of the pressure; and
moving the impeller assembly relative to the aortic valve of the patient to substantially smooth out spikes in the signal.
20. The method of claim 7 , wherein maintaining the average pressure comprises maintaining an average pressure of less than about 135% of the normal human average ventricular pressure.
21. The method of claim 20 , wherein maintaining the average pressure comprises maintaining an average pressure of less than about 125% of the normal human average ventricular pressure.
22. The method of claim 21 , wherein maintaining the average pressure comprises maintaining an average pressure of less than about 115% of the normal human average ventricular pressure.
23. The method of claim 22 , wherein maintaining the average pressure comprises maintaining an average pressure of less than about 105% of the normal human average ventricular pressure.
24. The method of claim 7 , wherein the sensor is positioned near the one or more inlets of the impeller assembly.
25. The method of claim 7 , wherein the sensor is positioned near a proximal portion of the impeller.
26. A catheter pump comprising:
an impeller assembly comprising an impeller and one or more inlets; and
a sensor configured to measure a pressure of blood flowing through the inlet(s) of the impeller assembly,
wherein the impeller assembly is configured such that the inlet(s) can be positioned in a left ventricle of the patient during a treatment procedure, the impeller assembly also configured to pump blood into an aorta of the patient at a flow rate of at least about 2 liters per minute (Lpm) and to maintain an average pressure of less than about 15 mmHg in the left ventricle of the patient.
27. The catheter pump of claim 26 , further comprising a processing unit programmed to process a signal detected by the sensor, the processing unit comprising a computer-readable set of rules to evaluate the signal to determine a pressure of blood in the left ventricle of the patient.
28. The catheter pump of claim 26 , wherein the impeller assembly is configured to pump blood through the aorta at a flow rate of at least about 4 Lpm.
29. The catheter pump of claim 26 , wherein the impeller assembly is configured to pump blood through the aorta at a flow rate in a range of about 4 Lpm to about 5.5 Lpm.
30. The catheter pump of claim 29 , wherein the impeller assembly is configured to pump blood through the aorta in a range of about 4.5 Lpm to about 5.5 Lpm.
31. The catheter pump of claim 26 , wherein the impeller assembly is configured to maintain an average pressure of less than about 10 mmHg in the left ventricle of the patient.
32. The catheter pump of 24 , wherein the impeller assembly is configured to maintain a pressure in a range of about 2 mmHg to about 8 mmHg.
33. The catheter pump of claim 32 , wherein the impeller assembly is configured to maintain a pressure in a range of about 3 mmHg to about 6 mmHg.
34. The catheter pump of claim 33 , wherein the impeller assembly is configured to maintain a pressure in a range of about 4 mmHg to about 5 mmHg.
35. The catheter pump of claim 26 , wherein the sensor is positioned near the inlet(s) of the impeller assembly.
36. The catheter pump of claim 26 , wherein the sensor is positioned near a proximal portion of the impeller.
37. A method of pumping blood through a patient, the method comprising:
advancing an impeller assembly through a vascular system of the patient to a left ventricle of the patient, the impeller assembly comprising an impeller and a sensor configured to measure a pressure of blood flowing through one or more inlets of the impeller assembly;
activating the impeller to pump blood through an aorta of the patient at a flow rate of at least about 2 liters per minute (Lpm); and
maintaining an average pressure in the left ventricle of the patient of less than about 135% of the normal human average ventricular pressure.
38. The method of claim 37 , wherein maintaining the average pressure comprises maintaining an average pressure of less than about 125% of the normal human average ventricular pressure.
39. The method of claim 38 , wherein maintaining the average pressure comprises maintaining an average pressure of less than about 115% of the normal human average ventricular pressure.
40. The method of claim 39 , wherein maintaining the average pressure comprises maintaining an average pressure of less than about 105% of the normal human average ventricular pressure.
41. The method of claim 37 , wherein the sensor is positioned near the one or more inlets of the impeller assembly.
42. The method of claim 37 , wherein the sensor is positioned near a proximal portion of the impeller.