What is the management plan for a patient with abnormal left ventricular (LV) strain of -15%?

Management of Abnormal Left Ventricular Strain of -15%

A left ventricular (LV) strain of -15% indicates abnormal myocardial function requiring cardioprotective therapy and close monitoring, even if ejection fraction is preserved. This value falls below the normal range (normal being more negative than -18%) and represents subclinical LV dysfunction that requires intervention 1.

Understanding LV Strain and Its Significance

LV global longitudinal strain (GLS) is a sensitive marker of myocardial function that can detect subclinical dysfunction before changes in ejection fraction become apparent. The normal range for LV GLS is:

• Normal: -18% or lower (more negative)
• Borderline: -16% to -18%
• Abnormal: -16% or higher (less negative) 1

A value of -15% is therefore clearly abnormal and indicates impaired longitudinal function of the left ventricle.

Management Approach

1. Initial Evaluation

• Assess for symptoms of heart failure
• Determine underlying etiology (cardiomyopathy, valvular disease, cardiotoxic therapy, etc.)
• Evaluate other cardiac parameters (ejection fraction, chamber dimensions, diastolic function)

2. Cardioprotective Treatment

• Initiate cardioprotective therapy with ACE inhibitors or ARBs with or without beta-blockers 2
• This recommendation is particularly strong for patients with abnormal strain but preserved ejection fraction (Stage B heart failure)
• These medications can prevent further deterioration of LV function

3. Monitoring Protocol

• Repeat LV ejection fraction and strain measurements every 3 months 2
• Perform more frequent assessments if cardiac symptoms develop
• Consider measuring cardiac biomarkers (troponin and BNP/NT-proBNP) based on clinical context and risk of cardiac toxicity 2

4. Special Considerations for Different Clinical Scenarios

For Cancer Patients Receiving Cardiotoxic Therapy:

• If the patient is receiving cardiotoxic cancer therapy with normal LVEF but abnormal strain:
  • Continue life-saving cancer treatment (treatment should not be altered solely based on changes in LV strain) 2
  • Initiate cardioprotective medications (ACE-I/ARB ± beta-blockers)
  • Consider cardio-oncology consultation 2

For Patients with Suspected Cardiomyopathy:

• An LV strain of -15% may be suggestive of pathologic LV hypertrophy, particularly in the gray zone of hypertrophic cardiomyopathy (HCM) 2
• Further imaging with cardiac MRI may be warranted to evaluate for late gadolinium enhancement, which would support a diagnosis of HCM 2

For Patients with Heart Failure:

• LV GLS ≤10% indicates significantly worse prognosis in heart failure patients 3
• At -15%, while concerning, the patient has not yet reached this more severe threshold
• Early intervention with guideline-directed medical therapy is crucial

Prognostic Implications

The prognostic significance of abnormal LV strain is well-established:

• In heart failure patients, baseline LV GLS is independently associated with long-term outcomes, including worsening heart failure and all-cause mortality 3
• Improvement in LV GLS over time is associated with better outcomes 4

Common Pitfalls to Avoid

1. Focusing only on ejection fraction: Normal ejection fraction does not rule out significant myocardial dysfunction. Strain imaging provides incremental prognostic information.

2. Delaying treatment: Do not wait for symptoms or ejection fraction decline before initiating therapy for abnormal strain.

3. Inconsistent follow-up: Regular monitoring is essential as LV dysfunction may progress silently.

4. Ignoring age-related changes: LV strain decreases with age, body weight, central obesity, and relative wall thickness 5, so interpretation should consider these factors.

By implementing early cardioprotective therapy and establishing a regular monitoring protocol, you can potentially prevent progression to more severe LV dysfunction and improve long-term outcomes for patients with abnormal LV strain.