A device for the excision of a heart valve via a percutaneous route having a proximal and distal end, comprising: - a radially expandable cutting instrument, ECI, (50, 50') capable of radial expansion from a closed to an open configuration, - wherein the open configuration provides a receptacle with a void having an aperture at one end, the distal edge of the aperture forming a cutting edge for excision of the heart valve, which receptacle is configured to receive and contain the excised heart valve, - wherein the ECI in the closed configuration, is configured for passage through the lumen of a delivery catheter, - wherein the ECI is at least partly conical in the open configuration, and - wherein the receptacle is configured to compact and store the excised heart valve by contraction of the ECI from the open to the closed configuration; - an expandable cutting block, ECB, capable of expansion from a closed to an open configuration, disposed adjacent to the cutting edge, - wherein the ECB in the open configuration provides a support surface to support the heart valve under excision by the ECI, - wherein the ECB in the closed configuration, is configured for passage through the lumen of the delivery catheter; and - a displacement mechanism (5, 6) for adjusting the distance between the cutting edge and the ECB characterised in that the ECI comprises an expandable cone formed from a sheet of material in the geometric shape of an annulus segment. - a radially expandable cutting instrument, ECI, (50, 50') capable of radial expansion from a closed to an open configuration, - wherein the open configuration provides a receptacle with a void having an aperture at one end, the distal edge of the aperture forming a cutting edge for excision of the heart valve, which receptacle is configured to receive and contain the excised heart valve, - wherein the ECI in the closed configuration, is configured for passage through the lumen of a delivery catheter, - wherein the ECI is at least partly conical in the open configuration, and - wherein the receptacle is configured to compact and store the excised heart valve by contraction of the ECI from the open to the closed configuration; - wherein the open configuration provides a receptacle with a void having an aperture at one end, the distal edge of the aperture forming a cutting edge for excision of the heart valve, which receptacle is configured to receive and contain the excised heart valve, the distal edge of the aperture forming a cutting edge for excision of the heart valve, which receptacle is configured to receive and contain the excised heart valve, - wherein the ECI in the closed configuration, is configured for passage through the lumen of a delivery catheter, - wherein the ECI is at least partly conical in the open configuration, and - wherein the receptacle is configured to compact and store the excised heart valve by contraction of the ECI from the open to the closed configuration; - an expandable cutting block, ECB, capable of expansion from a closed to an open configuration, disposed adjacent to the cutting edge, - wherein the ECB in the open configuration provides a support surface to support the heart valve under excision by the ECI, - wherein the ECB in the closed configuration, is configured for passage through the lumen of the delivery catheter; and - wherein the ECB in the open configuration provides a support surface to support the heart valve under excision by the ECI, - wherein the ECB in the closed configuration, is configured for passage through the lumen of the delivery catheter; - a displacement mechanism (5, 6) for adjusting the distance between the cutting edge and the ECB