“A discovery is said to be an accident meeting a prepared mind.” - Albert Szent-Gyorgyi

Fruits bore by cardiac patients today is result of years of perseverance, dedication, research by many geniuses. The wide spectrum of interventional cardiology today may not have foreseen by them. History of interventional cardiology has moved from diagnostic to various therapeutic procedures. Innovations, discoveries happened either by chance or intuition or by perseverance.

Evolution of diagnostic angiography
Diagnostic cardiac catheterization in horse dates back to 1711 when Stephen Hale’s first cardiac catheterization of a horse performed using brass pipes, a glass tube and the trachea of a goose. He measured blood pressure invasively first time. It was French physiologist Claude Bernard who coined the term “cardiac catheterization” and used catheters to record intracardiac pressures in animals in 1844.

The first documented cardiac cathterisation was performed by young surgeon Dr. Wener Forssman on himself in 1929, Eberswald, Germany. Forssman’s goal was to find a safe way to inject drugs and contrast material into the right atrium for cardiac resuscitation. He did venous cutdown on himself with assistance of a nurse and passed catheter till right atrium, and then walked down to X-ray room to document it with X-ray. He later on performed the same procedure 27 times. He was so much criticized for this that he had to leave the hospital. In 1941, Andre Cournand and Dickinson Richards at Columbia University and Bellevue Hospital in New York began the systematic exploration of normal and abnormal haemodynamics.They recorded intracardiac pressures and cardiac output in normal subjects and in patients with many forms of congenital and acquired heart disease. These investigators established cardiac catheterization as the basis for defining normal and disordered function of the cardiac pump and as a premier diagnostic technique in cardiology. Cope, Ross and Zimmerman disclosed the left heart during the following decade, and in 1956 Forssman, Cournard and Richards were awarded the Noble Prize for their studies on the heart. Cournand states in his acceptance speech “the cardiac catheter was...the key in the lock.”

While conducting an imaging procedure in which dye was to be injected into the aortic valve of a patient with valvular disease, Dr. Mason Sones a paediatric cardiologist at The Cleveland Clinic discovered that the catheter had accidentally entered the patient’s right coronary artery and, before it could be removed, 30 ml of contrast dye had been released. He expected the heart to fibrillate, but it did not and Sones discovered that the coronary arteries could tolerate contrast dye. Sones recalled, “I knew that night that we finally had a tool that would define the anatomic nature of coronary artery disease.”

Sones went on to perfect a revolutionary new technique for producing high quality diagnostic images of the coronaries using specially designed catheters. This breakthrough would make possible, for the first time, accurate diagnosis of coronary disease and set the stage for future therapeutic interventions, such as bypass surgery and, later on, coronary angioplasty.

No history of the development of coronary arteriography would be complete without acknowledging the important contributions of Drs Judkins and Amplatz. Both of these radiologists used the Seldinger percutaneous technique to gain access to the femoral artery. Independently, they designed preformed catheters, the conformity of which sought out the ostia of either the left or right coronary artery as well as facilitating access to the left ventricle. It was these preformed catheters that made successful engagement of the coronary ostia a much easier process that required far less training than the Sones’ technique, which required much more time to become skillful.

Evolution of Angioplasty
The development of percutaneous techniques on peripheral arteries also demonstrate the strict relationship between scientific method, clinical intuition, and the casualness of an accidental observation. While performing a routine peripheral angiography, Charles Dotter unintentionally introduced a guide and a catheter through a stenosis in the iliac artery, thus achieving the recanalization of the vessel (1963). In 1964, after a series of preliminary studies on cadavers, Dotter performed the first mechanical dilation of a peripheral artery in a living person

Dotter’s accidental catheter recanalization of a peripheral artery ushered in the era of intervention, crowned by Gruentzig’s balloon angioplasty in 1977. This achievement appears to be the result of a long process. For many years Gruentzig had been trying to solve the problem of uncontrolled dilations of the latex balloons available until then, but it was only in 1974 that he was able to prepare the first balloon catheter made polyvinylchloride, an instrument with which, from 1974 to 1977, he was able to perform many dilations of the stenoses of peripheral arteries. During the same period he practiced on an animal model (dog) to increase his experience with the dilation of coronary arteries using his miniaturized instruments, and published his famous 1976 poster presented at the Annual Scientific Meeting of the American Heart Association in Circulation. However, the international scientific community was not yet prepared for his revolutionary technique, and the paper prompted widespread skepticism among physicians. Only Gruentzig’s great determination led him to his achievements.

On September 14th, 1977, the coronary angiography performed by Gruentzig in a 38-year-old male patient revealed a high-grade stenosis of the proximal left anterior descending coronary artery just proximal to the first large diagonal branch. Two days later, the first coronary angioplasty procedure was performed without complications; in 2000, 23 years later, the same patient underwent a new control coronary angiography. Unfortunately, Gruentzig could not follow the destiny of his first human patient, since he died in an airplane crash in 1985

With the introduction of angioplasty, problems associated with it, that of acute closure due to dissection and long term restenosis were soon recognized. The concept of the stent grew directly out of interventional cardiologists’ experience with angioplasty balloons in the first decade of use (1977-87). Sometimes the wall of the coronary artery became dissected after balloon dilatation. Although the artery would be opened successfully using a balloon, in a small percentage of cases, the artery would collapse after the balloon was deflated — sometimes this might not happen until the patient had been moved to the recovery room. Since there was no interventional “fix” available, the only option for this patient was emergency bypass graft surgery to repair the problem. A second problem soon became evident as well. Approximately 30% of all coronary arteries began to close up again after balloon angioplasty. By the mid-80’s various radiologists and cardiologists were working on solutions to these problems, designing new devices in hopes they would provide more safety and durability to the procedures. Lasers, tiny “shavers”, rotational “polishers” — many tools were miniaturized to be delivered via catheter. One such device was the stent — a metal tube or “scaffold” that was inserted after balloon angioplasty. The first use of the word “stent” to indicate a device useful in reshaping an anatomical structure was in 1916, in the field of odontology. The word derives from the name of an English dentist, Charles Stent, who in 1856 invented a dental impression compound known as “Stent’s material”.

The stent itself was mounted on a balloon and could be opened once inside the coronary artery. Julio Palmaz and Richard Schatz were working on such a stent in the United States; others in Europe were developing their own designs. In 1986, working in Toulouse, France, Jacques Puel and Ulrich Sigwart inserted the first stent into a human coronary artery. In 1994 the first Palmaz-Schatz stent was approved for use in the United States. Over the next decade, several generations of bare metal stents were developed, with each succeeding one being more flexible and easier to deliver to the narrowing.

Introduction stents led to exponential rise in number of angioplasties world wide. Almost two million angioplasties were performed worldwide in 2001, with an estimated increase of 8% annually. It became the commonest medical intervention performed worldwide. But while stents virtually eliminated many of the complications of abrupt artery closure, restenosis persisted. Although the rates were somewhat lower, bare metal stents still experienced reblocking (typically at six-months) in about 25% of cases, necessitating a repeat procedure. The interventional cardiology community also learned that restenosis, rather than being a recurrence of coronary artery disease, actually was the body’s response to what Andreas Gruentzig called the “controlled injury” of angioplasty and was characterized by growth of smooth muscle cells — roughly analogous to a scar forming over an injury.

Problem of restenosis seemed to be resolved with introduction of the Cypher, first drug eluting stent from Cordis. This was polymer based sirolimus eluting stent. Sometimes referred to as a “coated” or “medicated” stent, a drug-eluting stent is a normal metal stent that has been coated with a pharmacologic agent (drug) that is known to interfere with the process of restenosis (reblocking). Restenosis has a number of causes; it is a very complex process and the solution to its prevention is equally complex. However, in the data gathered so far, the drug-eluting stent has been extremely successful in reducing restenosis from the 20-30% range to single digits. There are three major components to a drug-eluting stent:

• Type of stent that carries the drug coating
• Method by which the drug is delivered (eluted) by the coating to the arterial wall (polymeric or other)
• The drug itself – how does it act in the body to prevent restenosis?

Drug eluting stents have led to major revolution in the field of cardiology. With problem of restenosis seemingly conquered, it has become an alternative to CABG.

References

1. Mueller RL, Sanborn TA. The history of interventional cardiology: cardiac catheterization, angioplasty, and related interventions. Am Heart J 1995; 129 : 146-72.
2. Eugene Braunwald, Cardiology: the past, the present, and the future. JACC 2003.08.025. J Am Coll Cardiol 2003; 42 : 2031-41.
3. Thomas J Ryan. Medicine Over Five Decades The Coronary Angiogram and Its Seminal Contributions to Cardiovascular. Circulation 2002; 106 : 752-6.
4. Angioplasty From Bench to Bedside to Bench Spencer B King. Circulation 1996; 93 : 1621-29.