Systems and methods for selectively occluding the superior vena cava for treating heart conditions
Systems and methods and devices are provided for treating conditions such as heart failure and/or pulmonary hypertension by at least partially occluding flow through the superior vena cava for an interval spanning multiple cardiac cycles. A catheter with an occlusion device is provided along with a controller that actuates a drive mechanism to provide at least partial occlusion of the patient's superior vena cava, which reduces cardiac filling pressures, and induces a favorable shift in the patient's Frank-Starling curve towards healthy heart functionality and improved cardiac performance. The occlusion device may include a lumen obstructed by a relief valve that may permit fluid flow through the occlusion device to release an excessive build-up of pressure.
1. A method for unloading of cardiac preload and afterload, the method comprising:
pumping blood within a patient using a cardiac assist device to reduce cardiac afterload;
positioning a flow limiting element at a superior vena cava (SVC) of the patient; and
at least partially occluding the SVC via the flow limiting element over multiple cardiac cycles to reduce cardiac preload.
2. The method of claim 1 , wherein positioning the flow limiting element comprises intravascularly positioning the flow limiting element disposed on a catheter within the SVC, and
wherein the at least partially occluding the SVC comprises expanding the flow limiting element.
3. The method of claim 2 , further comprising contracting the flow limiting element within the SVC, the expanding and the contracting reducing the cardiac preload.
4. The method of claim 3 , further comprising repeating the expanding and the contracting over a course of a treatment.
5. The method of claim 1 , wherein the at least partially occluding the SVC via the flow limiting element comprises fully occluding the SVC via the flow limiting element.
6. The method of claim 1 , wherein the cardiac assist device is a ventricular assist device (VAD).
7. The method of claim 6 , wherein the VAD is a left ventricular assist device (LVAD).
8. The method of claim 1 , wherein the cardiac assist device is an intra-aortic balloon pump (IABP).
9. The method of claim 3 , wherein expanding the flow limiting element comprises expanding the flow limiting element to at least partially occlude the SVC for a first predetermined time interval and the contracting comprises contracting the flow limiting element for a second predetermined time interval over multiple cardiac cycles.
10. The method of claim 9 , wherein the first predetermined time interval is at least five times greater than the second predetermined time interval.
11. The method of claim 9 , wherein the first predetermined time interval is 5-20 minutes and the second predetermined time interval is 10-100 seconds.
12. The method of claim 1 , wherein the SVC is at least partially occluded for up to 95% of an hour.
13. The method of claim 1 , wherein the at least partially occluding further reduces the patient's diastolic volume and improves cardiac performance as measured by at least one of: reduced cardiac filling pressures, increased left ventricular relaxation, increased left ventricular capacitance, increased left ventricular stroke volume, increased lusitropy, reduced left ventricular stiffness or reduced cardiac strain.
14. The method of claim 1 , wherein the at least partially occluding creates a negative pressure sink in a right atrium of the patient, accelerating flow from a renal vein, thereby enhancing renal decongestion and promoting blood flow across a kidney of the patient.
15. The method of claim 1 , further comprising monitoring pressure differential across the flow limiting element in the SVC indicative of an amount or degree of occlusion in the SVC.
16. The method of claim 1 , further comprising:
outputting a first pressure signal via a first pressure sensor disposed proximal to the flow limiting element;
outputting a second pressure signal via a second pressure sensor disposed distal to the flow limiting element; and
determining pressure in the SVC based on the first pressure signal or the second pressure signal or both.
17. The method of claim 1 , further comprising determining pressure in the SVC.
18. The method of claim 3 , wherein the expanding and the contracting are caused by a controller operatively coupled to the flow limiting element.
19. The method of claim 18 , further comprising implanting the controller.
20. The method of claim 1 , wherein the flow limiting element is a balloon.
21. The method of claim 1 , further comprising transitioning a relief valve coupled to the flow limiting element from a closed position to an open position to permit fluid to flow through the SVC to a right atrium of the patient.
22. The method of claim 21 , wherein transitioning the relief valve from the closed position to the open position comprises transitioning the relief valve from the closed position to the open position at a pressure between 30-60 mmHg.