Invasive investigations and revascularisation

Invasive investigation of coronary artery disease is relatively expensive, and carries risks including a mortality of approximately 1 in 2000. It would not be practical or appropriate to perform invasive investigation in all patients with a clinical diagnosis of coronary artery disease, still less in the large numbers with chest pain and possible angina. Clinicians will refer for invasive investigation those: (i) with a high level of angina, needing revascularisation on symptomatic grounds; and (ii) who are likely to have a poor prognosis with medical treatment, and thus likely to benefit from revascularisation. Not all of these patients will have a high level of symptoms. In the late 1950s and early 1960s, there were major advances in the treatment of coronary artery disease ‐ the techniques of external cardiac massage, electrical cardioversion, and the introduction of lignocaine transformed the approach to acute myocardial infarction and arrhythmias, and led to coronary care units. At the same time, Sones and Judkins introduced methods of selective coronary arteriography, a prerequisite for coronary artery surgery. In the mid- and late-1960s, early forms of exercise ECG testing (Masters step test) and of isotope myocardial perfusion imaging (with caesium) were developed to identify those with severe coronary disease likely to benefit from coronary arteriography and revascularisation. In the 1960s and 1970s, large registries charted the natural history of patients after their coronary artery disease had been defined by arteriography, and showed poor prognosis of those with triple vessel disease or left main stem disease. Randomised clinical trials of coronary artery surgery in the late 1970s and early 1980s showed that, for these groups of patients, surgery conferred prognostic benefit as well as symptomatic relief of angina. This established the value of coronary arteriography in deciding the correct treatment. Invasive investigation is now taken to mean ‘left heart catheterisation’, comprising selective coronary arteriography with multiple views to show all major coronary vessels clearly without overlap or foreshortening, and contrast left ventriculography to show left ventricular function and any regional wall motion abnormality. It is used to assess the prognosis and hence need for revascularisation, as well as the anatomical (technical) suitability of the vessels for grafting or for angioplasty. In special circumstances, it may be used simply to confirm or refute the diagnosis of coronary artery disease, for example in airline pilots.