Immune checkpoint inhibitors are powerful cancer treatments that help the body's immune system fight tumors. However, in some patients, these drugs can cause the immune system to attack the heart, leading to a condition called immune checkpoint inhibitor-related myocarditis (ICI-M). This heart inflammation can be serious, so doctors need reliable ways to diagnose it early.
A new meta-analysis combined data from 3,568 patients across multiple studies to see which tests work best for detecting ICI-M. The results show that cardiac magnetic resonance imaging (CMR) is very helpful. About 63% of patients with ICI-M had abnormal CMR findings, and 65% showed a specific pattern called late gadolinium enhancement (LGE). Patients with LGE had about 5 times higher odds of having ICI-M compared to those without it. Another CMR finding, myo- or pericardial oedema (swelling of the heart muscle or lining), was seen in 16% of patients and also suggested higher odds of ICI-M, though this result was not statistically significant.
Blood tests also play an important role. Elevated cardiac troponins (cTn) and brain natriuretic peptides (BNP) were both significantly higher in patients with ICI-M. These markers indicate heart muscle damage or stress. Additionally, echocardiography (ultrasound of the heart) showed that about 36% of patients with ICI-M had a decreased left ventricular ejection fraction (LVEF), meaning the heart's pumping ability was reduced. Having a low LVEF increased the odds of ICI-M by about 5 times.
Importantly, the study also looked at which tests could predict major adverse cardiovascular events (MACE), such as heart failure or death. Both reduced LVEF and elevated troponin I were strong predictors. Patients with low LVEF had about 5 times higher odds of MACE, and those with high troponin I had even higher odds.
The takeaway is that no single test can diagnose ICI-M on its own. Instead, doctors should use a combination of heart MRI, blood tests, and echocardiography to get a complete picture. This multimodal approach helps catch heart inflammation early and manage it properly. The study is based on pooled data from many observational studies, so the results are estimates, not absolute truths. Patients and doctors should work together to interpret these tests in the context of each individual's situation.