Myocardial stress perfusion in asymptomatic patients: the silent ischemia makes the loudest sound.
According to T. Pezel et al.’s multivariate analysis, silent ischemia and unrecognised myocardial infarction are strongly associated with increased risk of major adverse cardiovascular events (MACE). These conditions, detectable by cardiovascular magnetic resonance imaging (MRI), are thus valuable long-term predictors for MACE’s incidence in asymptomatic patients with no prior cardiovascular events.
Further, Pezel et al.’s study of an asymptomatic cohort noted a 2.2% annualized MACE rate, an event rate close to that of MR-INFORM, which exclusively enrolled high-risk patients suffering from angina. This increased annual event rate can be explained by the cohort’s high number of inconclusive stress tests. Inconclusive stress tests are in themselves a marker of elevated risk of cardiovascular events.
As stated by JR Weir-McCall and SP Hoole, in the era of precision medicine, detailed phenotyping with imaging could result in more effective targeting of expensive emerging therapies. Better risk stratification with imaging may help better identify patients with most to gain. MRI-guided precision medicine will have to prove its mettle against cardiac computed tomography.
Take-home message: The high spatial and temporal resolution of MRI makes it crucial to the apprehension of cardiovascular risk in asymptomatic patients without prior cardiovascular events. MRI is invaluable to MACE risk estimation due to its accuracy in the detection of myocardial infarction and perfusion defects (silent ischemia). These are both long-term predictors of MACE incidence.