DEVELOPMENT AND INNOVATION IN CARDIOVASCULAR MEDICINE - Innovation in the Biopharmaceutical Industry - page 34

within the body. More recently, intravascular ultrasound methods have been devel-
oped using transducers mounted on the end of flexible catheters that can be inserted
percutaneously into coronary arteries to assess disease prior to and following inter-
vention (Tobis et al. , 1989). Thus, we again see a remarkable diagnostic invention
that reaches its full potential through several innovations and refinements.
X-ray imaging
Coronary heart disease has been the greatest challenge to cardiovascular medicine.
Successes in preventing and treating this disease have contributed most to the reduc-
tion in cardiovascular disease mortality. Long-term prognosis in individual patients
is related to the extent of atheromatous deposits within the coronary arteries (Mock
et al. , 1982). Imaging of coronary arteries is beyond the resolution of current ultra-
sound techniques, and still relies on an innovation of one of the earliest imaging
techniques, X-rays. Coronary angiography involves the introduction of a flexible
catheter through a small skin puncture, which can be advanced to the orifice of the
coronary arteries. Transient injections of contrast media allow visualisation of the
vessel lumen during X-ray examination.
The introduction of coronary angiography is a typical example of the incremen-
tal nature of medical advances and of the combination of serendipity and vision
that often underpins it. During a routine cardiac catheterisation, when aortography
was done to assess the patency of the aortic valve, the catheter inadvertently slipped
into the right coronary ostium, and a selective coronary angiogram was performed
(Hurst, 1985). This unexpected event led to the introduction of routine diagnostic
coronary angiography. The basic principles of angiography are unchanged, but sev-
eral refinements and innovations have enhanced its image quality and ease of use.
Initially recorded on cine film and later on videotape, modern systems rely on dig-
ital storage coupled with image enhancement. Together, these innovations provide
images of much better quality and with greatly reduced exposure of patients and
operators to radiation. Coronary stenoses (narrowings) can be assessed in terms of
their severity, distribution, and number, providing accurate prognostic information
and an essential guide to treatment. In this way, innovations that improved the effi-
ciency, diagnostic power, and safety of angiography have led to its routine use, and
underpinned the widespread introduction of coronary artery bypass surgery (Ryan,
2002). The development of coronary angioplasty and stenting can also be traced
through an innovative line from the technique of angiography. Catheters used for
angiography have undergone multi-step innovative developments in their design
fabrication and construction. One innovation in catheter design involved mount-
ing an inflatable balloon close to the catheter tip, which could be deployed within
coronary arteries to dilate a stenosis (Gruentzig et al. , 1979). Angioplasty was soon