Methods and devices providing transmyocardial blood flow to the arterial vascular system of the heart

Abstract

This invention relates to methods and devices providing transmyocardial blood flow or coronary revascularization for the treatment of coronary atherosclerosis and resulting myocardial ischemia by increasing the flow of blood from one or more oxygenated blood sources within the patient to one or more sites selected in the arterial vascular system of the heart using a channel for maintaining and regulating blood flow therebetween. A valved conduit or a self-maintained channel is created between the left ventricle reservoir of oxygenated blood and the coronary artery distal to an area of obstruction by surgical and percutaneous methods. Preferably, the conduit or self-maintained channel integrally regulates the flow of blood between the oxygenated blood source and the site selected in the arterial vascular system of the heart wherein an increase in blood flow is desired.

Description

FIELD OF THE INVENTION [0001] This invention relates to methods and devices providing transmyocardial blood flow or coronary revascularization for the treatment of coronary atherosclerosis and resulting myocardial ischemia. The invention increases the flow of blood from one or more oxygenated blood sources within the patient to one or more sites selected in the arterial vascular system of the heart using a channel for maintaining and regulating blood flow therebetween. More particularly, a valve is inserted into a channel created and maintained between, or a valved conduit is inserted between, the left ventricle reservoir of oxygenated blood and the coronary artery distal to an area of obstruction. BACKGROUND OF THE INVENTION [0002] Heart disease is a major medical ailment wherein arteries become narrowed or blocked with a build-up of atherosclerotic plaque or clot which reduces flow to tissues downstream or “distal” to the blockage. When this flow reduction becomes significant, a p...

AI Technical Summary

Benefits of technology

[0016] The present invention provides a method for increasing the flow of blood to a selected site in a patient's arterial vascular system of the heart. The method includes, the steps of: creating a channel for blood flow from an oxygenated blood source to the selected site in the arterial vascular system of the heart; maintaining the channel in an open position for blood flow through diastolic and systolic cycles of the heart; and regulating the blood flow in the channel to minimize blood flow from the coronary vascular system to the blood source during diastolic cycle of the heart.

[0017] The present invention also provides a method for performing a transmyocardial coronary revascularization procedure for the treatment of coronary atherosclerosis caused by an obstruction in the arterial vascular system. The method includes the steps of: creating a channel for blood flow from an oxygenated blood source to the arterial vascular system distal to the area of obstruction; maintaining the channel in an open position for blood flow through the diastole and systole cycles of the heart; and regulating the blood flow in the channel to minimize blood flow from the arterial vascular system to the blood source during the diastolic cycle of the heart.

[0018] A method for treating an obstruction in a patient's cardiovascular system using a non-expandable conduit made of biocompatible material is also provided by the present invention. The method includes the steps of: inserting the conduit completely through the myocardium of the patient's heart with one end of the conduit extending into the left ventricle and the other end of the conduit extending into the arterial vascular system distal to the area of obstruction; maintaining the conduit in an open position for blood flow through the diastolic and systolic cycles of the heart; and regulating the blood flow in the channel to minimize blood flow from the arterial vascular system to the left ventricle during the diastolic cycle of the heart.

[0019] Another method provided by the present invention increases the flow of blood to a selected site in a patient's arterial vascular system. The method includes the steps of: inserting one end of a conduit into the left ventricle; inserting the second end of the conduit into the arterial vascular system at the selected site; maintaining the conduit in an open position for blood flow through the diastolic and systolic cycles of the heart; and regulating the blood flow in the conduit to minimize blood flow from the arterial vascular system to the left ventricle during the systolic cycle of the heart.

Problems solved by technology

In fact, heart disease patients often die when coronary arteries become significantly blocked.

Although CABG surgery grafts have good long patency rates of about 60% to 90% over a ten year period, the isolation of the heart with the CPB and aortic cross-clamp carries a significant risk of mortality.

During prolonged periods on CPB, there is a greater chance for air and platelet embolization resulting from the artificial circuit.

For example, such debris can embolize into the neurovasculature and potentially cause a stroke.

It is believed that the inherent crushing force from a cross-clamp across the bridge of the muscular aortic arch may be associated with a high degree of tissue trauma and structural damage.

Additionally, blood clots formed at or adjacent to the cross clamp, perhaps in conjunction with the tissue trauma of clamping, may also be a source of unwanted complications.

In addition to the potential clinical complications associated with CABG surgery is also the cost of the time-consuming procedure.

Although these procedures are less traumatic than CABG surgery, the failure rate is often about 30-50% whereby the vessel narrows within a six month period and must be treated again.

The long-term artero-venous fistula that is created, however, has the potential for edema or other physiologic effects.

Unfortunately, most coronary arteries do not have adjacent cardiac veins and, thus, the disclosed approach may be limited in its ability to provide full revascularization.

Among the drawbacks in using the Wilk method is that the stent must be expandable and any valve therein must be integral with the stent.

The transluminal approach disclosed by Wilk can also have difficulty in delivering the expandable stent across coronary arteries which are substantially occluded.

Approximately 60% of CABG surgery procedures are performed on totally occluded vessels where percutaneous access would not be feasible.

However, these holes do not maintain a channel between the left ventricle and the native coronary circulation.

Also, these holes are not maintained in an open state once they are formed.

“First, any attempts to revascularize the wall of the left ventricle direct from the cavity of the ventricle are likely to be functional failures, even if technically successful . . . . In addition, there was a failure of myocardial contractility and a rise in left ventricular and diastolic pressure.

It was concluded that operations designed to revascularize the myocardium direct from the cavity of the left ventricle make the myocardium ischemic and are unlikely to succeed.”

While other attempts have been made to reduce the complications associated with “CABG” surgery through less-invasive, standard surgical approaches, they have been limited in their ability to fully revascularize the heart and provide a comparable degree of long-term success.

The prior art fails to disclose or fulfill the need for transmyocardial blood flow or coronary revascularization using a beating heart approach with either surgical or percutaneous techniques to create and maintain one or more regulated channels between the left ventricle and the arterial vascular system of the heart.

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