Surveying the landscape of interventional cardiology today, one sees a mature discipline using sophisticated technology and techniques that are backed by the findings of rigorous clinical trials. Many advancements have occurred in the field since the first angioplasty performed by Andreas Gruentzig in 1977. What began as a technique to treat a focal stenosis in patients with stable angina by physicians who performed diagnostic cardiac catheterizations has progressed to complex percutaneous interventions in unstable patients by highly trained and experienced operators. The work in coronary interventions also served as a catalyst for the development of therapies and technology to treat valvular heart disease with percutaneous valve replacement and repair. Understanding the history and development of interventional cardiology provides important insight and perspective to appreciate current practices as well as provide inspiration for future advancement of the field.

Many individual achievements provided the foundation for the development of interventional cardiology (Fig. 1-1). Werner Forssmann is credited as performing the first human cardiac catheterization in 1929 while working in Eberswalde, Germany.¹ He was inspired by the works of French physiologists Bernard, Chauveau, and Marey, who measured the intracardiac pressures in horses by directly inserting catheters into the heart. He hypothesized that accessing the heart directly with a catheter would provide a safer mechanism to deliver therapeutic drugs. Unfortunately, he did not have the support of his department chief, who thought such a procedure was reckless and likely fatal. Despite his chief’s disapproval, he was unrelenting in his pursuit and decided to perform the procedure on himself. With the help of a unsuspecting nurse, he cut down to his left brachial vein and inserted a urinary catheter as far as it would go.

He then traveled with the nurse to the basement where the x-ray machine was located and documented the catheter location in the right atrium. His self-experimentation resulted in disciplinary action, and as a result, Forssmann was not able to pursue any further study on the subject.²

Much of the development of right heart catheterization and hemodynamic assessment is credited to the work of Andre Cournand and Dickinson Richards at Bellevue Hospital in New York, which resulted in a 1956 Nobel Prize in Medicine that was shared with Forssmann.

Refinements in right heart catheterization over the next 2 decades eventually led to the desire to better understand left heart hemodynamics and valvular function through catheterization. After working out much of the details of accessing the left ventricle in a canine model, Henry Zimmerman performed the first left heart catheterization on a human in 1950 via a radial artery approach in Cleveland, Ohio.³ Early left heart catheterizations consisted of hemodynamic assessments and injection of contrast into the ventricle and aorta to assess left ventricular function and valvular disease. The coronary arteries were indirectly assessed by these methods but were not adequate for diagnostic quality.⁴ The concern was that the contrast media would cause ischemia and ventricular fibrillation. The need to obtain diagnostic assessment of coronary blockages, however, was becoming more important with the advent of coronary artery bypass surgery.

Interestingly, the first direct coronary angiography occurred by mistake in 1958. While performing a routine left heart catheterization at the Cleveland Clinic, Mason Sones pulled back across the aortic valve and prepared for an aortogram. As the injection started, Dr. Sones noted the catheter tip was directly engaged in the right coronary artery and filled the vessel with viscous diatrizoic acid (Hypaque) contrast media before the catheter was able to be removed. Fortunately, the patient did not develop ventricular fibrillation but rather asystole, which was converted to sinus rhythm by having the patient cough 3 or 4 times. Despite this near-fatal complication, Dr. Sones saw the potential need for diagnostic angiography and was instrumental in developing techniques to access and visualize coronary arteries.^5,6

Up to this point in the mid-20th century, advancements in invasive cardiology had been diagnostic, which still left therapies for coronary artery and valvular disease in the hands of the surgeons while cardiologists watched. This relationship, however, would soon change thanks to a determined and somewhat controversial figure, Charles Dotter. A radiologist by training, Dotter was well published in the field of angiocardiography and, by age 32, was professor and chairman of the radiology department at University of Oregon Medical School. He entered into the field of interventional radiology by coincidence while attempting an abdominal aortogram for an assessment of renal artery stenosis in 1963. Dotter advanced his catheter through a stenotic right iliac artery in order to reach the aorta and, in the process, recanalized the artery. He presented his findings at the Czechoslovak Radiologic Conference in June 1963 to a very receptive audience, where he concluded “the angiographic catheter can be more than a tool for passive means for diagnostic observation.”⁷

He would return to the United States to further refine his technique of “Dottering” stenotic vessels with Melvin Judkins by designing specialized catheters to serially dilate stenotic lesions. His methods were not well received by surgeons in the United States despite successfully treating many patients and saving them from limb amputation. Even though Dotter had little support back home, his techniques were championed by Werner Porstmann in Berlin and Eberhard Zeitler in Engelskirchen, Germany. Zeitler would later teach Andreas Gruentzig this technique, who would go on to adapt the concept to coronary arteries.^8,9

Andreas Gruentzig’s initial training after medical school was in the field of epidemiology, but he soon became interested in peripheral vascular disease while studying at the Ratchow Clinic in Darmstadt, Germany. During his training, he became interested in Dotter’s technique in treating stenotic vessels. Gruentzig then moved to Zurich, Switzerland, to accept a position in the angiology department at the University Hospital. He quickly set out to begin the Dotter technique and invited Zeitler to Zurich to help perform his first dilation.

Despite embolizing plaque to the distal leg and obstructing flow, Gruentzig remained convinced of the promise of the procedure to treat atherosclerosis not only in the peripheral arteries but also in the heart. He recognized that the coronary arteries posed a much different challenge than the large and relatively straight peripheral vessels and that another technique besides serially dilating with a catheter was needed. Gruentzig’s answer to this challenge was a slender, steerable balloon-tipped catheter that could be inflated to expand the lesion.

He set out to design his catheter with his assistant Maria Schlumpf. Early attempts to construct the catheter took place at his kitchen table with the help of Maria’s husband, Walter, and Gruentzig’s wife, Michaela. He soon consulted with Dr. Hoph, a professor of chemistry at University of Zurich, who advised Gruentzig to use polyvinyl chloride to construct his balloon in order to maintain its desired shape and size. After some initial homemade prototypes, Gruentzig partnered with Schneider Needle Company to manufacture his balloon catheter. He tested his catheter in a dog model where the discrete stenosis in the artery was created with silk ligature. Gruentzig was able to use his catheter to cross the stenosis and perform a balloon dilation to successfully treat the stenosis. He presented this proof of concept at the 1976 American Heart Association meeting to a lackluster response¹⁰ (Fig. 1-2).

Undeterred, Gruentzig was determined to use his technique to treat heart disease in humans and tried unsuccessfully to convince surgeons in Zurich to allow him to try his balloon angioplasty technique on patients undergoing bypass surgery. He eventually partnered with a cardiologist, Richard Myler, in San Francisco at St. Mary’s Hospital, who persuaded the cardiac surgeon, Elias Hanna, to test his procedure. After successfully performing the procedure in humans, Gruentzig returned to Zurich to treat patients in hopes of avoiding bypass surgery. His initial attempt was on a patient with complex disease, as well as severe peripheral vascular disease, which his catheter was not able to navigate, and the procedure was aborted. This setback illustrated the need for better lesion and patient selection to ensure success of this new procedure, and thus, Gruentzig started looking for lower risk patients without complex disease.

He soon found his next patient—a 38-year-old man with severe angina and a proximal discrete lesion. After discussing the experimental nature of the procedure with the patient and getting his consent, Gruentzig successfully performed his first balloon angioplasty procedure on September 16, 1977. The patient’s angina was successfully treated, and the patient did well after his procedure. The patient even underwent a follow-up heart catheterization in 1987 that demonstrated a patent vessel free of residual stenosis. Gruentzig successfully performed 4 more balloon angioplasties and presented his case series at the 1977 American Heart Association meeting. This meeting was a much different experience than the 1976 meeting; he presented to packed house and received a standing ovation. He would publish his early findings in The Lancet as a Letter to the Editor in February 1978.¹¹

The success of Gruentzig’s balloon angioplasty technique ushered in a paradigm shift in approaching coronary disease, and cardiologists and radiologists from around the world came to Zurich to learn the technique. Gruentzig knew that in order for his idea to remain successful that his technique must be properly taught to skilled operators rather than disseminated to the masses. He was worried that if careless physicians performed his procedure then fatal outcomes would doom his idea. Thus, Gruentzig established his first teaching course in 1978, where 28 physicians traveled to Zurich to watch him perform cases. While at the course, physicians learned how to perform the procedure, but just as important, they also were educated on the complications, pitfalls, and tricks to rescue a procedure. Gruentzig continued his teaching courses in Zurich, until he was recruited to come to Emory University, where his courses were continued until his untimely death in 1985 and beyond. Many other courses were also created to train the early adaptors of angioplasty. The first balloon angioplasties in the United States occurred simultaneously in San Francisco by Richard Myler and in New York by Simon Stertzer, so that neither individual would be the first to perform the procedure.¹²

As more physicians were taught balloon angioplasty and brought the technique to their practice, the equipment and techniques began to evolve to overcome some of the limitations of the procedure. Tortuous vessels and the inability to recross a lesion that had shut down during inflation led to the development of over-the-wire systems. John Simpson took this idea further by first crossing the lesion with a wire and then advancing the balloon over the wire. This allowed for the development of lower profile balloons and expanded the technique to stenosis in distal segments. As the technology and operator experience advanced, so did the success of the procedure as well as its ability to challenge bypass surgery. However, there had not been any definitive evidence to compare angioplasty to bypass surgery, a proven therapy. All the evidence for angioplasty consisted of an international registry established by the National Heart, Lung, and Blood Institute (NHLBI). To better understand the optimal treatment of coronary disease, the NHLBI awarded the first randomized controlled trial comparing angioplasty to bypass surgery in 1987.¹³