A Patent of Selection for a Jacketed Cardiac Stent

February 9, 2009 at 3:49 pm 1 comment

Hi, this is Rabbi, Dr. Yosef Freedland, Surgeon, and Patent Attorney on Medical Devices at Appelfeld Zer Fisher.

Let’s get down to some specific medical devices, for example cardiac stents, and how to write a patent on an invention in crowded terrain.

Before continuing, I must apologize to Ze’ev Fisher, of Appelfeld Zer Fisher, for writing this Blog in several posts; which is not the way Ze’ev Fisher prefers. However, this is the only way to go, in my humble opinion, in order to provide appropriate background related to the heart.

C’mon Ze’ev, have a heart.

Stent Background

Everybody, besides people in Kazakhstan like Borat Sagdiyev, are aware about stents.

For the sake of Borat, we will examine a bit about stents and specifically Cardiac Stents.

A stent is a mesh in a tubular configuration that is expanded in a hollow passage to open up an area that is blocked, usually by tissue. Cardiac stents are expanded in a heart artery to open up a partially blocked area of the artery.

The expanded stent forms a conduit through the blocked area of the artery so that blood flows relatively unimpeded.

There are two major types of cardiac stents as of this post: bare metal stents and jacketed stents.


Bare metal stents have a tendency to allow tissue to grow between the holes in the metal mesh. When there is a lot of tissue growing “up through the cracks”, meaning through the holes in the stent, the blood vessel may become blocked again; referred to as restenosis.

Jacketed stents include a tubular stent frame covered by a jacket. The jacket often comprises a dense mesh of polymer fibers which prevents tissue from growing between the large holes in the stent frame.

Jacketed stents usually prevent restenosis but result in other problems.

Any stent, whether bare metal or jacketed, gets coated on the inside surface with a flat layer of tissue cells soon after installation.

These tissue cells, referred to as endothelial cells, can break away from the polymer fibers. Mobilized endothelial cells attract platelets, and form a large clump of dangerous cells, referred to as an embolism.

An embolism is a very nasty creature that can lodge in a blood vessel that feeds an organ with nourishment from blood and cause a portion of organ tissue to die.

Up to 2% of all jacketed stents eventually result in necrosis of vital organs as a result of mobilized endothelial cells that have formed into an embolism.

It is not very good to have dead tissue in an organ, particularly in the brain where the dead tissue causes a stroke. Then again, an embolism isn’t very good when it lodges in the heart, kidneys, or lungs, either. So the best idea is to stay away from things that can cause an embolism.

No Good Options

And this doesn’t leave a stent recipient with many good options: If you opt for a bare metal stent, you can get a re-blockage of the vessel.

If you opt for a jacketed stent, you can end up with a stroke (or worse). Come on guys what to do?

OK, so this is Rabbi, Dr. Yosef Freedland, Surgeon, and Patent Attorney signing off just before we finish explaining how bad the problem is that YOU are going to solve.


Entry filed under: Medical Device Patents, Patent Drafting Lessons. Tags: , , , , .

Basic Principles of Patent Drafting – Summary Jacketed Cardiac Stent – Suggested Invention

1 Comment Add your own

  • 1. cardiac bypass surgery  |  December 1, 2009 at 10:13 pm

    here are two main coronary arteries supplying blood to the heart, the left coronary artery and the right coronary artery. The left main coronary artery, which splits into two further branches known as the left anterior descending artery and the left circumflex artery, supplies most of the heart with blood; thus if it is diseased, can cause major problems. The right coronary artery supplies blood to the right side of the heart and the lower part of the left side of the heart.

    Most people with angina Temporary chest pain or feeling of pressure that occurs because the heart is not getting enough oxygen due to the diminished blood flow. have blockages in one or more of these arteries and/or their branches. A cardiologist (heart specialist) will perform various tests to determine the location and extent of the blockage.


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