In the human body, various organs contain fluids both in liquid and gaseous forms within tissue layers or cavities formed by tissue. These liquids may or may not be contained under pressure. The tissue walls around these cavities are normally designed to confine these liquids to specific areas of the body. Blood as in the heart and vasculature in order to preserve its volume and transport oxygen to tissue, gastric and intestinal fluids as in the stomach and intestines in order to transport remains of digestion out of the body after nutrients are absorbed, urine in the bladder in order to expel liquid waste from the body, fluid within the eye to maintain its shape and passage of light, are examples of such tissue fluid-confining systems. During medical procedures within these cavities it is of extreme importance to control the fluid within. The most common example is cardiopulmonary bypass during open heart surgery, although, in all procedures associated with the systems above emphasis is placed on control of the fluid within these cavities or organs. For this control, extra space often is required to conduct these interventions; therefore, highly invasive procedures may be required for surgery within these cavities, especially while maintaining organ function. The most complex example of these interventions is beating heart surgery, involving procedures that are conducted “off pump.” For less invasive procedures, especially those within the vascular system, access ports or conduits which allow for fluid communication, control, and tissue closure within the organ being repaired are therefore required.
Because of the importance of heart function and the complexities associated with this pressurized system, some of the most complex procedures associated with bodily fluids are performed on this organ. Several of these procedures would benefit from an access port or conduit that can be connected to the heart while maintaining a fluid tight seal with tissue surfaces.
One procedure that would benefit from an improved fluid tight access port or conduit into the heart would be the implantation of a ventricular assist device (VAD), such as a left ventricular assist device (LVAD) between the left ventricle and the aorta, or a right ventricular assist device (RVAD) between the right ventricle and the pulmonary artery. The LVAD includes a mechanical pump that assists a failing heart by circulating blood through an alternative conduit from the left ventricle to the aorta. According to current techniques for LVAD implantation, which typically are performed on-pump, a hole is formed in the apex of the left ventricle and a conduit is secured within the hole via sutures. The RVAD similarly includes a mechanical pump that assists a failing heart by circulating blood through an alternative conduit from the right ventricle to the pulmonary artery. RVAD implantation techniques, which also tend to be performed on-pump, involve forming a hole in the lateral wall of the right ventricle and securing a conduit within the hole via sutures. After establishing a fluid tight connection between the conduit and the ventricular wall, an inlet tube of the VAD is attached to the conduit, which allows blood to flow from the ventricle to the pump. Due to the substantial risks of cardiopulmonary bypass, particularly for patients with advanced heart failure, it would be highly desirable to implant the VAD during an off-pump procedure. However, due to challenges in forming a hole in the ventricle of an active heart and then securely suturing a traditional conduit in place, on-pump techniques remain the standard for VAD implantation.
Another procedure that would benefit from an improved fluid tight access port or conduit into the heart would be heart valve replacement, which is the most common open heart cardiovascular surgery procedure. Currently, most heart valve repair or replacement surgeries are conducted on a heart at rest under cardiopulmonary bypass through a large median sternotomy. This surgery is highly invasive, and therefore, the population that may survive such a procedure is limited to those who are strong surgical candidates. In recent years, valves for minimally invasive deployment through the femoral artery or apex of the heart have been developed. These valves may be used in patients that would under other conditions be deemed non-candidates. The use of these valves may also in the future reduce complications associated with cardiopulmonary bypass and large incisions in surgical candidates. For those procedures through the apex of the heart, it has been shown that bleeding complications are directly associated with 50% increased mortality, and thus an access port or conduit that would reduce bleeding complications, decrease incision size, and simplify closure would be of great benefit.
Yet another procedure that would benefit from an improved fluid tight access port or conduit into the heart would be the construction of an alternative conduit between the left ventricle and the aorta (an apicoaortic conduit, or AAC). This procedure creates a double-outlet left ventricle (LV) to treat a variety of complex congenital LV outflow obstruction (fibrous tunnel obstruction, aortic annular hypoplasia, tubular hypoplasia of the ascending aorta, and patients with diffuse septal thickening, severe LV hypertrophy, and a small LV cavity) as well as adult-onset aortic stenosis in patients with complicating preoperative conditions (previous failed annular augmentation procedures, previous infection, previous CABG with patent anterior internal mammary artery grafts, and a porcelain ascending aorta). However, the AAC insertion procedure has been poorly accepted, with or without cardiopulmonary bypass, and has not been as technically straightforward as direct aortic valve replacement. Nonetheless, several studies have demonstrated that AAC insertion successfully lessens the LV-aortic pressure gradient, preserves or improves ventricular function, and maintains normally distributed blood flow through the systemic and coronary circulation.
While there have been several techniques described, the most commonly employed method is the lateral thoracotomy approach with placement of the AAC to the descending aorta or a median sternotomy. The current techniques and technology available to perform AAC insertion were originally designed to be performed on-pump, either with an arrested or fibrillating heart, and are therefore, highly invasive. Although off-pump cases have been described, they can be technically difficult due to the shortcomings of presently available conduits and systems for installing such conduits. For example, because existing conduits require the use of sutures to reliably secure the conduits in place, it is often difficult for surgeons or other clinicians to insert such sutures reliably in active cardiac and/or vascular tissue.
The various devices and systems described herein may be utilized as an accompaniment with any number of surgical procedures to gain access through a variety of possible tissues. For example, the devices and systems may be utilized to provide fluid access across a tissue wall for various procedures, such as, but not limited to, implantation of a VAD, establishing an AAC, establishing a port for inter-ventricular repairs (e.g., valve repair, valve replacement, or ablation procedures, etc.), establishing valved and/or open conduits (including bypass conduits) to augment native blood vessels in order to treat a variety of vascular conditions (e.g., aortic valvular disease, congestive heart failure, left ventricle outflow tract obstructions (LVOTO), peripheral arterial obstructions, small vessel obstructions, etc.), providing a conduit across a urinary bladder wall, providing a conduit across a gall bladder wall, providing a conduit into a thoracic cavity, providing a conduit into an abdominal cavity, providing a conduit into a cecal cavity, providing access into the cornea or eye walls, or providing access across or into any other tissue wall structures. Accordingly, the devices and systems described herein may be utilized with any of the aforementioned procedures and/or to gain access through any of the aforementioned tissue walls.
Certain related devices, systems, and methods have been previously described, such as those described in U.S. Pat. No. 7,846,123, PCT Patent Publication WO 2012/103546, and PCT Patent Publication WO 2012/106422, which are hereby incorporated by reference herein in their entirety. However, improved devices, systems, and methods for implanting and using a connector in a tissue wall are desirable, which may be used to establish, maintain, control, and close a fluid communication between opposing surfaces of the tissue wall.
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