Severe heart failure occurs when the heart muscle is weakened and cannot pump enough blood to meet the body’s needs. For patients nearing the end stage of this condition, a heart transplant may offer the best chance for long-term survival and an improved quality of life. The extensive evaluation process relies on objective measures to assess the severity of heart function. One important metric used to gauge the heart’s pumping strength and determine initial eligibility is the Ejection Fraction (EF).
Understanding Ejection Fraction
Ejection Fraction quantifies the efficiency of the heart’s main pumping chamber, the left ventricle. It calculates the percentage of blood pushed out of the left ventricle with each contraction, or heartbeat. For example, an EF of 60% means that 60% of the blood volume is ejected into the body’s circulation during a single pump.
The measurement is obtained using an echocardiogram, a non-invasive imaging test that utilizes sound waves to create moving pictures of the heart. A normal Ejection Fraction falls within the range of 50% to 70% for healthy adults. A reading between 41% and 49% is considered mildly reduced, suggesting possible heart damage. An EF under 40% indicates heart failure with reduced ejection fraction (HFrEF), meaning the heart muscle is not contracting effectively enough to circulate blood.
The Ejection Fraction Threshold for Consideration
A very low Ejection Fraction is a nearly universal requirement for a patient to be considered a heart transplant candidate. The specific threshold that signals end-stage heart failure is often cited as a left ventricular Ejection Fraction (LVEF) below 30%. Some transplant centers utilize an even stricter criterion, looking for an LVEF of 20% or less to move forward with a full evaluation.
An extremely low EF indicates severe impairment of the heart’s systolic function, classified as Stage D heart failure. At this stage, conventional medical therapies are often insufficient to manage symptoms or prevent premature death. While a severely reduced EF is a necessary marker of disease severity, it is not the sole qualification for listing. The EF identifies patients who are sick enough to warrant the aggressive evaluation required for transplant candidacy.
Comprehensive Criteria for Heart Transplant Listing
Listing a patient for a heart transplant requires a comprehensive assessment beyond the Ejection Fraction, focusing on the patient’s overall medical picture and prognosis. A primary criterion is that the heart failure must be refractory, meaning it remains severe despite maximal medical and device therapies. These patients typically exhibit severe symptoms, classified as New York Heart Association (NYHA) Class III or IV, even while on optimal medications.
Objective measures of functional capacity are heavily relied upon, such as the peak oxygen consumption (VO2 max) during a cardiopulmonary exercise test. A VO2 max of less than 12 to 14 mL/kg/min indicates poor functional status and a high risk of death within one year without a transplant. Patients must also be free of significant co-morbidities that could compromise the success of the surgery and the long-term survival of the new heart.
Absolute contraindications often include irreversible pulmonary hypertension, which would prevent the new heart from pumping effectively against high resistance in the lungs. Other issues that disqualify a patient are:
- Active infections.
- Recent cancer diagnoses.
- Severe and irreversible dysfunction of other major organs like the liver or kidneys.
- Evidence of substance abuse.
Finally, a psychosocial evaluation ensures the patient has the necessary support and willingness to adhere to the complex, lifelong medication and lifestyle regimen required after transplantation.