Historically, the assessment of myocardial ischemia has been a useful tool in clinical cardiology for risk stratification and decision-making. For this assessment, in the field of nuclear cardiology, Hachamovitch and colleagues, in their large-scale observational study, determined that an ischemic burden (IB) exceeding 10% of ventricular mass, in the absence of extensive myocardial necrosis, identified patients who benefited from an invasive strategy and early revascularization compared with medical therapy in terms of survival. (1)
Over the years, both medical treatment and revascularization techniques have improved significantly. This led to the conduct of randomized trials to identify which subgroups benefited from an initial invasive strategy (2-4). Among these was the ISCHEMIA trial, which demonstrated that, in patients with moderate-to-severe ischemia, both initial medical therapy and invasive therapy reduce major cardiovascular events and mortality without significant differences. (5) However, it is important to note that this study used the performance of a coronary angiography (via CT angiography) as an initial evaluation criterion to rule out severe left main coronary artery disease or non-obstructive coronary artery disease, thereby excluding these patients from the study.
In light of the bibliographic references presented thus far, it is evident that the study titled “Evaluation of the Clinical Management and Follow-up of Patients with Severe Myocardial Ischemia Detected by Triggered SPECT” (6) provides an interesting update on these topics within the context of a public hospital in our country. Of primary relevance is the selection of patients with IB greater than or equal to 10% on a myocardial perfusion scan. The study evaluates the therapeutic approach (invasive versus conservative) adopted by treating physicians in this group upon finding these results of severe myocardial ischemia.
This observational, retrospective, single-center study by Herrero et al. provides valuable insights, as it demonstrates that treating physicians were significantly more likely to order an initial invasive study in the cohort of patients with a IB of 16% or higher. Furthermore, this subgroup of patients had the highest percentage of revascularization. This could be the starting point for reconsidering the value of IB in guiding therapeutic management.
This study had limitations, such as the considerable number of follow-up losses and the short median duration of longitudinal evaluation (18 months). However, it demonstrated a higher number of major cardiovascular events in revascularized patients, with a significant number occurring within the first month after the procedure. Given this finding, longer-term follow-up could be valuable to assess the performance of the medical treatment arm, considering that adherence may decline over time.
In conclusion, this is a valuable observational study that provides evidence to inform decision-making in real-world medical practice.