Is Global Longitudinal Strain (GLS) needed in cancer monitoring when Ejection Fraction (EF) is reduced?

From the Guidelines

Global Longitudinal Strain (GLS) is still valuable in cancer monitoring even when Ejection Fraction (EF) is already reduced. While a reduced EF clearly indicates cardiac dysfunction, GLS provides complementary information that can detect subtle changes in heart function before further EF deterioration occurs. GLS measures the heart muscle's deformation during contraction and is more sensitive to early myocardial damage from cardiotoxic cancer therapies like anthracyclines and trastuzumab.

Key Points to Consider

• In cancer patients with reduced EF, monitoring GLS can help assess treatment response to cardioprotective medications (such as beta-blockers, ACE inhibitors, or ARBs), determine if cancer therapy modifications are needed, and predict further cardiac deterioration.
• The standard approach involves obtaining baseline GLS before cancer treatment, then regular follow-up measurements during and after therapy, with a relative reduction of >15% from baseline considered clinically significant, as suggested by 1.
• GLS monitoring in these patients allows for earlier intervention and potentially prevents irreversible cardiac damage, even when EF impairment is already established.
• Studies have shown that early elevation in cardiac biomarkers such as troponin or changes in cardiac strain during cancer-directed therapy precede changes in LVEF, as assessed by two-dimensional echocardiography 1.
• The American Society of Echocardiography (ASE) and European Association of Cardiovascular Imaging (EACVI) consensus suggested a practical approach for GLS use in patients undergoing chemotherapy, with a GLS reduction <8% from baseline not meaningful, but >15% from baseline very likely abnormal 1.

Clinical Application

• GLS should be used in conjunction with other echocardiographic parameters, such as diastolic function and tissue Doppler measures, to provide a comprehensive assessment of cardiac function during and after completion of cancer-directed therapy 1.
• Imaging should adhere to established imaging standards, relying on consistent imaging technologies to limit technical variability.
• Other imaging modalities such as cardiac MRI or MUGA may be considered if an echocardiogram is not available or technically feasible.

From the Research

Importance of GLS in Cancer Monitoring

• Global Longitudinal Strain (GLS) is a significant parameter in monitoring cancer patients, especially when Ejection Fraction (EF) is reduced 2, 3.
• GLS can detect subclinical myocardial dysfunction, which may not be apparent with EF measurements alone 4, 5.
• Studies have shown that a reduction in GLS can be an early indicator of cardiotoxicity, even when EF is within normal limits 2, 3.

Comparison of GLS with EF

• GLS has been found to be more sensitive than EF in detecting cardiotoxicity in patients undergoing chemotherapy 4, 3.
• EF may not always accurately reflect the extent of myocardial damage, whereas GLS can provide a more detailed assessment of myocardial function 6, 5.
• The use of GLS in conjunction with EF can provide a more comprehensive understanding of cardiac function in cancer patients 2, 3.

Clinical Implications

• The early detection of cardiotoxicity using GLS can prompt timely intervention and potentially prevent long-term cardiac damage 2, 4.
• GLS can be used to monitor patients undergoing cardiotoxic chemotherapy and to assess the effectiveness of cardioprotective therapies 6, 3.
• The use of GLS in clinical practice can improve patient outcomes and reduce the risk of cardiotoxicity in cancer patients 2, 5.