Minimally invasive atrio-ventricular valve treatment by chordae adjustment

{
  "publication_number": "US2017290663A1",
  "country": "US",
  "kind": "A1",
  "title": "Minimally invasive atrio-ventricular valve treatment by chordae adjustment",
  "abstract": "Minimally invasive catheters and methods are provided for adjusting the chordae associated with an atrio-ventricular valve. The catheter is adapted to engage a selected chord and draw it into a pair of transversely spaced, receptive clamps at the distal end of the catheter in readiness to be clamped The clamps are part of a prosthetic cord assembly that includes the clamps and a cord attached to each of the clamps. The effective length of a natural chord can be increased by employing a long prosthetic cord and clamping and severing the natural chord between the clamps. The effective length of a chord can be decreased by drawing the natural chord into the distal end of the catheter to a hairpin shape and clamping the legs of the hairpin-restrained chord. The chord need not be severed when its effective length is being reduced.",
  "claims": [
    "1. A catheter for selectively adjusting the length of a chord of the chordae tendineae associated with an atrio-ventricular valve, comprising: an elongate catheter shaft having proximal and distal ends and a longitudinally extending axis; a pair of clamps releasably carried at the distal end of the catheter shaft, the clamps being disposed in transversely spaced relation, each clamp having distally facing portions adapted to receive a chord disposed transversely of the catheter axis, the clamps being closeable to securely grip a chord received within the clamps at spaced locations along the chord; a chordal snare movable in an axial direction between the spaced clamps between an extended position beyond the distal end of the shaft and a retracted position within the shaft, the snare being configured to selectively engage a chord, the snare being retractable into the distal end of the catheter to draw an engaged chord into the receptive clamps; and a prosthetic cord segment attached to each of the clamps, the clamps being operable to close and clamp the chord at spaced locations. 2. A catheter as defined in claim 1 adapted to increase the effective length of the chord further comprising: a severing element moveable longitudinally between the clamps and engageable with the clamped chord to sever the selected chord while that chord is clamped; the length of the prosthetic cord being such that when released from the catheter the effective length of the chord will have been increased. 3. A catheter as defined in claim 2 further comprising: the cutting element is moveable longitudinally within a guiding channel formed through the chordal snare. 4. A catheter as defined in claim 3 wherein the cutting element is arranged to sever the chord between the clamps. 5. A catheter as defined in claim 1 adapted to decrease the effective length of the chord further comprising: the snare being moveable into the distal end of the catheter to draw an engaged chord into a hairpin shape having a pair of legs and a bight, with portions of the chord adjacent the distal ends of the legs being drawn into the receptive clamps; the length of the prosthetic cord being less than the length of the hairpin portion of the chord so that when released from the catheter the effective length of the chord will have been decreased. 6. A catheter as defined in claim 1 further comprising: the clamps being formed to be inherently resilient and biased toward a closed position; a removable restraining member associated with each of the clamps to maintain each clamp in an open configuration receptive to a chord; whereby when a chord is contained in the receptive clamps, the restraining member can be removed and the clamps will close to grip the chord at spaced locations. 7. A catheter as defined in claim 1 further comprising: the clamps being formed to be malleable and maintained on the catheter to be open and receptive to a chord; the clamps being disposed in sockets formed on diametrically opposite sides of the catheter, the clamps being slidable proximally in the sockets, the sockets being tapered in a proximal direction; whereby when a chord is contained in the receptive clamps, the clamps can be drawn proximally in their respective slots to enable the tapering portions of the sockets to deform the clamps to grip the chord at spaced locations. 8. A method for selectively increasing the effective length of a chord of the chordae tendineae associated with an atrio-ventricular valve, comprising: constraining a segment of a selected chord; providing a prosthetic cord assembly including a pair of clamps connected to each other by a prosthetic cord; applying the clamps to the chord at two locations; and severing the chord at a location between the clamps, whereby the effective length of the chord is determined by the length of the prosthetic cord assembly. 9. A method for selectively shortening the effective length of a chord of the chordae tendineae associated with an atrio-ventricular valve, comprising: constraining a segment of a selected chord into a hairpin-shaped loop having a pair of distally extending legs and a bight; providing a prosthetic cord assembly including a pair of clamps connected to each other by a prosthetic cord; applying the clamps to the chord at locations adjacent the distal ends of the legs of the loop; and the prosthetic cord being shorter than the length of the constrained segment of the chord, whereby the effective length of the chord is shortened."
  ],
  "description_excerpt": "The invention relates generally to minimally invasive devices and techniques for adjusting the closing positions of the leaflets of a malfunctioning atrio-ventricular (A-V) valve by selectively adjusting the length of one or more chordae associated with the valve.\n\nThe heart has a left side and a right side, each side including an atrium and a ventricle. The atria receive blood returning through veins to the heart and the ventricles pump blood away from the heart, through arteries, to circulate blood through the body. The blood returns to the right side of the heart through the venous system. The heart also includes four one-way valves (aortic, pulmonary, mitral and tricuspid) that function to maintain unidirectional blood flow as the heart contracts in a pumping stroke (systole) and then relaxes and expands to fill the ventricles (diastole). Each side has an A-V valve (the tricuspid and mitral valves) that controls flow from its atrium to its associated ventricle, and each ventricle has an output valve (the pulmonary valve and aortic valve). When the heart muscle contracts (systole) blood is pumped from both ventricles through their respective output valves. Oxygenated blood from the left ventricle is pumped through the aortic valve to the aorta and branching arteries while blood from the right ventricle is pumped through the pulmonary valve to the lungs where it is oxygenated. The oxygenated blood from the lungs is returned to the heart and is received in the left atrium. The right atrium receives return blood via the venous system.",
  "cpc": [
    "A61F 2/2457",
    "A61F 2/2466"
  ],
  "ipc": [
    "A61F 2/24"
  ],
  "inventors": [
    "Lars Erickson",
    "Wayne Boucher"
  ],
  "filing_date": "2016-04-12",
  "publication_date": "2017-10-12",
  "priority_date": "2016-04-12",
  "application_number": "US-201615097181-A",
  "family_id": "59999060",
  "cited_by_count": 11,
  "citations": [
    "US5964758A",
    "US20070270643A1",
    "US20090143639A1",
    "US20140114404A1",
    "US20150150634A1",
    "US20160015410A1"
  ]
}