Pulmonary vein stent and method for use

Abstract

Ablation of the pulmonary veins causes damage to the tissue which may affect the viability of the tissue. By placing a stent, a vascular endoprosthesis, within a target pulmonary vein it is possible to protect the functionality of the veins after the ablation procedure. Placement of a stent, endoprosthesis or mere circuit interrupting structure into a target pulmonary vein, without ablation, prevents aberrant electrical activity in the pulmonary veins from interfering with the electrical activity of the left atrium. The stent, endoprosthesis or circuit interrupting structure may also be coated or comprised of a drug-eluting compound, loaded with a drug which inhibits arrhythmia.

Description

[0001] Related Patent Application[0002] This patent application is a continuation of U.S. app. Ser. No. 09 / 687,776, now U.S. Pat. No. 6,______, which claims priority to provisional patent application 60 / 159,343, filed Sep. 13, 1999.FIELD OF THE INVENTIONS[0003] The inventions described below relate to the field of implantable medical devices. Specifically the invention relates to endoluminally placed prosthesis known as stents. More specifically, the invention relates to the placement of stents in the pulmonary veins which have advantages for the treatment of atrial fibrillation.BACKGROUND OF THE INVENTIONS[0004] Atrial fibrillation (AF) is a form of heart disease that afflicts millions of people. It is a condition in which the normal contraction of the heart is interrupted, primarily by abnormal and uncontrolled action of the atria of the heart. The heart has four chambers: the right atrium, right ventricle, the left ventricle, and the left atrium. The right atrium pumps de-oxygena...

AI Technical Summary

Benefits of technology

The patent text describes a method for treating atrial fibrillation, a heart condition that causes blood flow disruptions and can lead to stroke and death. The method involves placing a stent in the pulmonary veins, which are the vessels that carry blood from the lungs. The stent placement is done endoluminally, meaning it is done through a vein in the lung. The technical effect of this method is that it reduces the risk of inducing ventricular fibrillation, a potentially life-threatening arrhythmia, and avoids the need for a large amount of drugs to be injected in the blood stream. This reduces the risk of side effects on all other organs in the body.

Problems solved by technology

When the left atrium or the right atrium fails to contract, contracts out of sequence, or contracts ineffectively, blood flow within the heart is disrupted.

The arrhythmia, known as atrial fibrillation, can cause weakness of the heart due to reduced ventricular filling and reduced cardiac output, stroke due to clot formation in a poorly contracting atria, which may lead to brain damage and death, and even life threatening ventricular arrhythmias.

Electrical defibrillation has two major problems: the therapy causes substantial pain, and has the potential to initiate a life threatening ventricular arrhythmias.

The pain associated with the electrical shock is severe and unacceptable for many patients.

The potential for inappropriate induction of ventricular fibrillation by the shock intended to defibrillate the atrium exists.

The induction of ventricular fibrillation has great potential to result in death in just a few minutes if no intervening therapy is provided.

Even with careful algorithms to deliver shocks to the periods in the ventricular contraction cycle when the heart is not susceptible to shock induced ventricular fibrillation, the risk of setting off a ventricular fibrillation remains substantial.

While the drugs are in the blood stream, they are available throughout the body to cause side effects on all other organs.

There are several disadvantages to the transient introduction of systemic drug levels by an implantable device.

Systemic effects resulting from such delivery may result in detrimental effects to ventricular cardiac conduction.

These detrimental effects could be life threatening, and several studies suggest that use of these drugs actually leads to higher mortality.

The large amount of drugs required for systemic delivery of therapeutic doses demands a larger, less comfortable device than smaller dosages would allow.

The large quantity of drug in the implantable reservoir of such a system is potentially more dangerous if it develops a leak or is ruptured.

Lastly, the large quantity of drugs required to obtain therapeutic levels in the entire body may cost substantially more than that required to treat a specific site within the heart.

Focal ablation of the region within or adjacent to the pulmonary vein to terminate atrial fibrillation with different energy transfer techniques such as cryoablation, RF ablation, laser ablation, ultrasound ablation, and microwave ablation causes damage to the tissue which may affect the viability of the tissue.

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