NUCLEAR stress testing can be used to guide physicians when selecting the appropriate treatment course in patients with suspected heart disease. This is based on findings from the first large-scale study to assess the impact of stress testing on patient management in the full spectrum of individuals with varying degrees of myocardial ischaemia and heart function.
Lead author Alan Rozanski highlighted the importance of the study design: “There is keen interest in assessing how measurement of myocardial ischemia during stress testing can help shape physicians’ decision to refer patients for coronary revascularisation procedures, but this issue has not been well studied among patients who have underlying heart damage.” Rozanski added: “Our study, which evaluated a large number of patients with pre-existing heart damage who underwent cardiac stress testing, finally addresses this clinical void.”
The team analysed the records of more than 43,000 patients who underwent nuclear stress testing with suspected coronary artery disease between 1998 and 2017 at Cedars Sinai Medical Center, Los Angeles, California, USA. The median follow-up for morality or survival was 11 years. Patients were grouped according to their level of myocardial ischaemia during stress testing and also their left ventricular ejection fraction (LVEF). Low LVEF measurements are indicative of prior heart damage, potentially from scarring because of a previous heart attack.
This study showed that the frequency of myocardial ischaemia varies based on heart function. Less than 8% of the 39,883 patients classified as having normal heart function (LVEF >55%) were found to have ischaemia. Conversely, more than 40% of those with reduced heat function (LVEF <45%) also had myocardial ischaemia. The researchers also showed that the presence of myocardial ischaemia increases the risk of death in people with normal and reduced heart function. Interestingly, performing bypass procedures or percutaneous coronary interventions in patients with no or mild ischaemia during the stress test did not improve survival. However, among individuals with severe ischaemia, early revascularisation was associated with more than 30% reduction in mortality. This was the case in cases with and without heart damage.