Devices and methods for cardiovascular reflex control via coupled electrodes

Abstract

Devices, systems and methods are disclosed by which the blood pressure, nervous system activity, and neurohormonal activity may be selectively and controllably reduced by activating baroreceptors. A baroreceptor activation device is positioned near a baroreceptor, preferably a baroreceptor located in the carotid sinus. A control system may be used to modulate the baroreceptor activation device. The control system may utilize an algorithm defining a stimulus regimen which promotes long term efficacy and reduces power requirements / consumption. The baroreceptor activation device may utilize RF-coupled or other electrodes to activate the baroreceptors. The electrodes may be adapted for connection to the carotid arteries at or near the carotid sinus, and may be designed to minimize extraneous tissue stimulation.

Description

[0001]This application is a continuation of U.S. application Ser. No. 10 / 402,393, filed Mar. 27, 2003. This application also claims the benefit of provisional application No. 60 / 368,222, filed on Mar. 27, 2002. This application is also a continuation-in-part of U.S. application Ser. No. 09 / 964,079, filed on Sep. 26, 2001, now U.S. Pat. No. 6,985,774, which was a continuation-in-part of U.S. application Ser. No. 09 / 671,850, filed on Sep. 27, 2000, now U.S. Pat. No. 6,522,926, the full disclosures of which are incorporated herein by reference.1. FIELD OF THE INVENTION[0002]The present invention generally relates to medical devices and methods of use for the treatment and / or management of cardiovascular and renal disorders. Specifically, the present invention relates to devices and methods for controlling the baroreflex system for the treatment and / or management of cardiovascular and renal disorders and their underlying causes and conditions.[0003]Cardiovascular disease is a major cont...

AI Technical Summary

Benefits of technology

[0013]To address hypertension, heart failure and their associated cardiovascular and nervous system disorders, the present invention provides a number of devices, systems and methods by which the blood pressure, nervous system activity, and neurohormonal activity may be selectively and controllably regulated by activating baroreceptors. By selectively and controllably activating baroreceptors, the present invention reduces excessive blood pressure, sympathetic nervous system activation and neurohormonal activation, thereby minimizing their deleterious effects on the heart, vasculature and other organs and tissues.

[0016]In a particular aspect of the present invention, systems for inducing a baroreceptor signal to effect a change in the baroreflex system of a patient comprise a baroreceptor activation device and a control system. The baroreceptor activation device is positionable in, or in come cases on, a blood vessel, e.g., in a vascular lumen or over an outer surface of the blood vessel proximate a baroreceptor so that activation of the device can induce a baroreceptor signal in the baroreceptor. The control system is coupled to the baroreceptor activation device and includes a processor and a memory. The memory includes software defining a stimulus or activation regimen which can generate a control signal as a function of the regimen. The coupling between the baroreceptor activation device and the control system includes at least one wireless link between the device and the control system, the link usually but not necessarily being provided across a vascular wall. Alternately, direct wireless linkage between an implanted controller and an implanted activation device is sometimes preferred to reduce the need for tunneling to implant cables. The activation device typically comprises an antenna, coil, or the like, implanted in a blood vessel, adjacent a baroreceptor, and the control system typically comprises an antenna, coil, or the like, implantable at a site in the patient's body remote from the activation device, typically being located in a venous lumen adjacent to the arterial or venous implantation site of the activation device. Venous sites for coil or antenna implantation will usually be preferred.

Problems solved by technology

Cardiovascular disease is a major contributor to patient illness and mortality.

Hypertension is a leading cause of heart failure and stroke.

It is the primary cause of death in over 42,000 patients per year and is listed as a primary or contributing cause of death in over 200,000 patients per year in the U.S. Accordingly, hypertension is a serious health problem demanding significant research and development for the treatment thereof.

Hypertension occurs when the body's smaller blood vessels (arterioles) constrict, causing an increase in blood pressure.

Because the blood vessels constrict, the heart must work harder to maintain blood flow at the higher pressures.

Although the body may tolerate short periods of increased blood pressure, sustained hypertension may eventually result in damage to multiple body organs, including the kidneys, brain, eyes and other tissues, causing a variety of maladies associated therewith.

The elevated blood pressure may also damage the lining of the blood vessels, accelerating the process of atherosclerosis and increasing the likelihood that a blood clot may develop.

This could lead to a heart attack and / or stroke.

Sustained high blood pressure may eventually result in an enlarged and damaged heart (hypertrophy), which may lead to heart failure.

It is characterized by an inability of the heart to pump enough blood to meet the body's needs and results in fatigue, reduced exercise capacity and poor survival.

It has been reported that the cost of treating heart failure in the United States exceeds $20 billion annually.

Accordingly, heart failure is also a serious health problem demanding significant research and development for the treatment and / or management thereof.

Heart failure results in the activation of a number of body systems to compensate for the heart's inability to pump sufficient blood.

The cardiac, renal and vascular responses increase the workload of the heart, further accelerating myocardial damage and exacerbating the heart failure state.

Although each of these alternative approaches is beneficial in some ways, each of the therapies has its own disadvantages.

For example, drug therapy is often incompletely effective.

Some patients may be unresponsive (refractory) to medical therapy.

Drugs often have unwanted side effects and may need to be given in complex regimens.

These and other factors contribute to poor patient compliance with medical therapy.

Drug therapy may also be expensive, adding to the health care costs associated with these disorders.

Likewise, surgical approaches are very costly, may be associated with significant patient morbidity and mortality and may not alter the natural history of the disease.

Baropacing also has not gained acceptance.

These include the invasiveness of the surgical procedure to implant the nerve electrodes, and postoperative pain in the jaw, throat, face and head during stimulation.

In addition, it has been noted that high voltages sometimes required for nerve stimulation may damage the carotid sinus nerves.

Energizing the implanted electrode structure, however, presents a number of difficulties.

In particular, it is undesirable to run leads to the electrode structure through the arterial lumen and / or through an arterial or to a lesser extent venous wall.

Such connection is particularly challenging if the target baroreceptors or other receptors are at or near the carotid sinus.

This is a particular problem with fully implanted systems which have a limited battery or other power source.

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