Can a normal ejection fraction (EF) pre-operatively become mildly reduced post-operatively following cardiac surgery for valve repair?

From the Guidelines

Yes, it is normal and often temporary to experience a mildly reduced ejection fraction following cardiac valve repair surgery. After cardiac surgery, the heart may temporarily function at a lower capacity due to several factors including the effects of cardiopulmonary bypass, myocardial stunning from surgical manipulation, inflammatory responses, and the heart's adaptation to the newly repaired valve. This reduction in ejection fraction typically resolves within weeks to months as the heart recovers from the surgical trauma and adjusts to the improved hemodynamics, as noted in the 2008 ACC/AHA guidelines for the management of patients with valvular heart disease 1.

Some key points to consider in this context include:

• The importance of close follow-up after surgery to evaluate prosthetic valve function and assess left ventricular (LV) function, with an echocardiogram performed soon after surgery to serve as a baseline for subsequent comparisons 1.
• The potential for little change in LV systolic function within the first few weeks of surgery, with ejection fraction possibly deteriorating compared to preoperative values due to reduced preload 1.
• The significance of reduction in LV end-diastolic dimension as a marker of the functional success of valve replacement, which declines significantly within the first week or two after surgery and correlates with the magnitude of increase in ejection fraction 1.

During the recovery period, patients are usually monitored with follow-up echocardiograms to track improvement in cardiac function. Medications that may be prescribed during this recovery phase include beta-blockers, ACE inhibitors, or ARBs to support heart function and manage blood pressure. Patients should follow their cardiologist's recommendations for activity levels, medication adherence, and follow-up appointments to ensure optimal recovery. Most patients will see gradual improvement in their ejection fraction as the heart muscle recovers and adapts to the repaired valve's function.

From the Research

Ejection Fraction Changes After Cardiac Surgery

• A decrease in ejection fraction after cardiac surgery for valve repair is a common phenomenon, as observed in a study published in 2, which found a significant decrease in left ventricular ejection fraction (mean, -8.8) at early echocardiography (mean, 5 days postoperatively).
• The magnitude of the early decline in ejection fraction was similar in patients who had mitral valve repair and replacement, suggesting that the type of surgery may not be a significant factor in this decrease 2.
• Factors independently associated with a lower postoperative ejection fraction include a lower preoperative ejection fraction, the presence of atrial fibrillation, advanced New York Heart Association functional class, greater left ventricular end-diastolic and end-systolic dimensions, and larger left atrial size 2.

Recovery of Left Ventricular Function

• Recovery of ventricular function after surgical correction of mitral regurgitation is often incomplete, but factors such as valve repair (vs replacement), freedom from preoperative myocardial infarction, operation in the 1990s, greater preoperative ejection fraction, and smaller left ventricular dimensions are associated with higher ejection fraction at follow-up 3.
• Patients with an ejection fraction of less than 50% at discharge are less likely to recover normal ejection fraction during long-term follow-up, highlighting the importance of early intervention and optimal surgical timing 3.
• A study published in 4 found that patients with heart valve disease and low LVEF can benefit from heart valve surgery, which can significantly improve left ventricular reverse remodeling and cardiac function.

Heart Failure with Mildly Reduced Ejection Fraction

• Heart failure with mildly reduced ejection fraction (HFmrEF) is a emerging frontier in clinical characteristics, prognosis, and treatment, with recent studies indicating that patients with HFmrEF may benefit from similar therapies to those with LVEF ≤40% 5.
• A study published in 6 found that heart failure with preserved ejection fraction (HFpEF) after left-sided valve surgery is prevalent and associated with unfavorable outcomes, but rarely recognized, highlighting the need for increased awareness and diagnosis of HFpEF in patients after valve surgery.