From surgery to recovery: Measuring success through quality of life and functional improvements after cardiac surgery

Abstract

Coronary artery disease and aortic valve stenosis are highly prevalent cardiovascular diseases worldwide, resulting in substantial morbidity and mortality. Surgical interventions, such as coronary artery bypass grafting and surgical aortic valve replacement, offer significant therapeutic benefits, including enhanced postoperative quality of life (QoL) and functional capacity, which are key indicators of surgical success. This editorial reviews recent studies on postoperative QoL and functional outcomes in patients undergoing cardiac surgery. Factors such as preoperative health, age, intensive care unit stay duration, surgical risk, and perioperative complications could influence these outcomes. Cardiac rehabilitation is pivotal in enhancing patient function, reducing frailty and improving long-term QoL.

Key Words: Quality of Life; Functional capacity; Cardiac surgery; Coronary artery bypass grafting; Surgical aortic valve replacement; Cardiac rehabilitation

Core Tip: Postoperative quality of life (QoL) and functional capacity are essential markers of successful cardiac surgery outcomes. This editorial reviews recent studies highlighting substantial postoperative improvements, particularly with the cardiac rehabilitation integration. Critical factors include preoperative health, age, length of intensive care unit stay, and perioperative complications. Standardized tools like Short Form Health Survey-36 and EuroQOL-5D are vital for evaluating these metrics and guiding patient recovery.

INTRODUCTION

Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality globally, accounting for ~17.9 million deaths annually[1]. Among these, coronary heart disease and aortic stenosis are particularly common and often require surgical interventions such as coronary artery bypass grafting (CABG) and surgical aortic valve replacement (SAVR)[2]. These procedures have been shown to improve survival rates and relieve symptoms. However, the ultimate success of cardiac surgery is increasingly measured by improvement in quality of life (QoL) and functional capacity[3,4]. Health-related QoL is a multidimensional concept that encompasses physical, emotional and social well-being[4]. Functional capacity is another important outcome that reflects the practical impact of surgery on a patient's daily life and overall independence[5]. Functional capacity refers to a patient’s ability to perform physical activities, including walking or climbing stairs, and is commonly assessed through tests like the 6-min walking test. QoL reflects a broader assessment of overall well-being, encompassing physical, emotional, and social dimensions. Together, these measures provide a comprehensive overview of the patient's recovery and long-term health status, especially among those with heart failure[6] or cardiomyopathy[7].

Postoperative QoL and functional capacity are influenced by various factors. Preoperative health, age, intensive care unit (ICU) stay, surgical risk, and perioperative complications all play important roles in determining outcomes[8]. Assessment of QoL and functional capacity is typically performed using standardized instruments. The Short Form Health Survey-36 (SF-36) is one of the most widely used and provides a comprehensive assessment across eight health domains[9,10]. Older patients undergoing cardiac surgery often present with multiple comorbidities, increasing their risk of complications, readmission, and mortality. Survival rates vary based on factors such as age, comorbid conditions, and length of ICU stay. Studies show that patients who required an ICU stay of ≥ 5 d post-surgery had a 1-year survival rate of 46.2%, while those who were discharged earlier had a 1-year survival rate of 72.4%[11]. Long-term data indicate an overall survival rate of 67.8% at 10 years after surgery[12]. However, survival decreases significantly with age. In patients over 75 years, the 10-year survival rate was 44.6%, compared to 74.6% in younger cohorts (P < 0.001).

The main risks associated with CABG include infection, bleeding, stroke, and graft failure. Long-term risks may include the need for revascularization procedures due to progression of atherosclerosis[13]. In addition, patients with diabetes, older age, or chronic kidney disease are at a higher risk. Similarly, SAVR carries risks such as infection, bleeding, stroke, and valve dysfunction[14]. Older patients and those with frailty or multiple comorbidities are particularly vulnerable to postoperative complications.

Cardiac rehabilitation (CR) programs play a critical role in improving postoperative outcomes. These multidisciplinary programs include supervised exercise training, education on heart-healthy living, and counseling to reduce stress and improve mental health. Studies have consistently shown that CR can significantly improve functional capacity, reduce morbidity and mortality, and improve QoL in patients with heart failure or undergoing cardiac surgery[15,16]. Therefore, the success of cardiac surgery should not only be measured by survival rates, but also by the extent to which it improves patients' QoL and functional capacity[17-19]. Understanding the factors that influence these outcomes and implementing comprehensive assessment tools are critical to optimizing patient care.

QOL AND FUNCTIONAL CAPACITY AFTER CARDIAC SURGERY

QoL is a crucial outcome indicator after cardiac surgery as it encompasses the physical, emotional, and social well-being of patients. Cardiac surgery such as CABG and SAVR aims not only to prolong life but also to improve QoL of patients suffering from severe coronary artery disease and aortic stenosis. Several factors influence QoL postoperatively. Preoperative health, including the presence of comorbidities, such as diabetes, hypertension, or chronic kidney disease, has a significant impact on the recovery course[20,21]. Age is another crucial factor; older patients often recover more slowly and may face additional challenges such as reduced mobility and increased dependence on caregivers, which can negatively affect QoL[22]. Length of stay in the ICU is also crucial; longer ICU stays are associated with a higher risk of complications, which may hinder recovery and affect QoL[22]. Perioperative complications, including infection, bleeding, and cardiac arrhythmia, can negatively affect QoL by prolonging recovery time and increasing physical and emotional burden on patients[23]. In addition, the type of surgical procedure and the associated surgical risk play a significant role. For example, minimally invasive techniques can offer faster recovery times and better QoL outcomes compared to traditional open-heart surgery[24-26]. These instruments, such as the SF-36 and the EuroQOL-5D, measure various health domains, including physical functioning, mental health, social functioning, and general health perception. Studies using these instruments have consistently shown that patients undergoing CABG or SAVR report significant improvements in both physical and mental health domains postoperatively[27].

In addition, a Mediterranean diet, rich in fruits, vegetables, whole grains, lean proteins, and healthy fats, has also been associated with better cardiovascular health and recovery after surgery[28]. We recommend avoiding foods high in saturated fats, salt, and sugar. A diet that includes omega-3 fatty acids (found in fish like salmon) and antioxidants (from fruits like berries) may help reduce inflammation and support cardiovascular health[28].

Functional capacity, defined as the ability to perform activities of daily living, is another critical measure of recovery and overall health after cardiac surgery. It reflects the practical impact of surgical interventions on a patient's daily life and independence. Improved functional capacity after surgery is indicative of successful recovery and improved cardiac function[29]. For example, airway abnormalities are common after cardiac surgery and are often due to prolonged intubation and mechanical ventilation. These problems can significantly affect functional capacity by reducing exercise tolerance and overall physical endurance[30]. Reduced muscle strength, particularly of the respiratory and peripheral muscles, further contributes to reduced functional capacity[31].

Various assessment tools are used to evaluate functional capacity. The cardiopulmonary exercise test (CPET) provides a comprehensive assessment of cardiovascular and pulmonary responses to exercise, making it a gold standard for assessing functional capacity[32]. The Duke Activity Status Index (DASI) is another valuable tool that assesses functional capacity based on the patient's ability to perform specific activities and provides insight into their daily functional status[33]. The 6-min walking test and the Barthel Index are also commonly used to assess functional capacity and physical endurance[34].

INTERPLAY OF FACTORS INFLUENCING POSTOPERATIVE OUTCOME

Factors influencing QoL and functional capacity could interact with each other. Age is a vital factor influencing postoperative recovery. However, age could interact with other variables such as comorbidities, including diabetes, hypertension, and chronic kidney disease, compounding these effects[35]. For instance, older patients with diabetes may have delayed wound healing, raising the risk of infections and further hindering physical recovery. Mental health also plays a crucial role, as depression and anxiety are common after cardiac surgery and are linked to reduced physical activity and poor adherence to rehabilitation[36]. Psychological conditions can either motivate or impede recovery, underscoring the importance of integrated mental health support in CR programs. Malnutrition and sarcopenia, prevalent in older patients with prolonged hospital stays, exacerbate muscle loss, lower immune function, and increase susceptibility to complications, further delaying recovery[37]. Social support is another critical factor -patients with strong family or caregiver networks are more likely to follow rehabilitation plans, reducing the risk of depression and improving QoL[38]. Understanding these interactions requires multidimensional assessment models that concurrently evaluate physical, psychological, nutritional, and social domains. Tools like the Kansas City Cardiomyopathy Questionnaire and the DASI could provide valuable insights into these interrelated factors[39]. Emerging technologies, including machine learning and big data analytics, are also aiding in the identification of interaction patterns, paving the way for more personalized CR approaches.

IMPACT OF PERIOPERATIVE COMPLICATIONS ON LONG-TERM OUTCOMES

Perioperative complications significantly influence long-term outcomes in cardiac surgery patients[40-42]. Stroke, occurring in 1%-5% of cases, is among the most serious complications, leading to lasting deficits in mobility, speech, and cognition. This reduces functional capacity, impairs CR effectiveness, and lowers overall QoL[43]. Postoperative stroke patients may have up to a 30% lower 5-year survival rate compared to those without stroke. Infections, including surgical site infections (SSIs), mediastinitis, and pneumonia, are common and can delay recovery by weeks or months. Bleeding is another significant complication. Despite advances in point-of-care coagulation monitoring and newer hemostatic therapies, blood transfusion rates remain high (≥ 50%) in high-risk patients, contributing to increased morbidity and mortality[44]. Acute kidney injury, occurring in 20%-30% of patients post-CABG, is closely linked to higher mortality and recurrent cardiovascular events[45,46]. Even mild renal dysfunction can impair physical function, prolong recovery, and negatively impact QoL. Addressing these complications through early intervention and targeted rehabilitation is crucial for improving long-term outcomes.

PROTOCOL AND IMPACT OF CR

CR plays an essential role in the postoperative recovery and has significant impacts on both QoL and functional capacity[47,48]. CR programs are comprehensive and include supervised exercise training, patient education, and psychosocial support, all aimed at promoting cardiovascular health and improving physical and mental well-being[49]. These programs are tailored to the individual patient needs, facilitate a gradual return to normal activities, and reduce the risk of subsequent cardiac events[50].

CR typically involves a progressive exercise program tailored to individual patients. For instance, low-intensity aerobic exercises like walking or cycling are often prescribed in the early stages, and as the patient progresses, strength training and high-intensity interval training may be included[51-53]. The intensity, frequency, and duration should be based on the patient’s fitness level and surgical recovery. In addition, many patients face mental health challenges after cardiac surgery, such as depression and anxiety. Including psychological support in CR programs, like cognitive-behavioral therapy or relaxation techniques, can significantly improve emotional well-being and recovery. Studies have shown that psychological interventions can enhance adherence to rehabilitation programs and improve outcomes. Furthermore, a heart-healthy diet plays a crucial role in the recovery process. Nutritional guidance should include advice on reducing saturated fats, increasing fiber intake, and promoting a Mediterranean-style diet rich in vegetables, whole grains, and lean proteins.

CR protocols differ significantly depending on the type of cardiac surgery performed. Patients undergoing CABG typically require comprehensive rehabilitation that targets cardiovascular endurance, wound healing, and prevention of graft occlusion[54]. The primary goals are to enhance functional capacity, reduce the risk of recurrent ischemic events, and manage risk factors such as hypertension and hyperlipidemia. However, patients undergoing SAVR, especially older individuals, often require more cautious and gradual rehabilitation protocols[55]. The primary focus is on improving lung function, preventing valve-related complications, and enhancing physical endurance.

The appropriate exercise dose in CR is guided by individual tolerance and clinical efficacy, with CPET and echocardiography used for risk stratification and assessment[6]. CR programs vary in intensity (50%-95% of peak heart rate or exercise capacity), duration (20-80 min per session), and modality, including cycling, treadmill walking, and circuit training. For older patients with reduced exercise tolerance, CR begins with low-impact activities such as chair exercises or short walks, gradually increasing in intensity as tolerated. Patients with comorbidities like diabetes or hypertension require CR programs focused on blood sugar and blood pressure management, with continuous monitoring during exercise and dietary adjustments. Additionally, the complexity of surgery influences CR timelines - patients undergoing complex procedures, such as SAVR with complications, benefit from prolonged supervised rehabilitation and closer follow-up compared to those with simpler surgeries. These strategies ensure CR is personalized, enhancing safety and long-term outcomes across diverse patient populations

Studies have consistently shown that patients participating in CR programs experience significant improvements in functional capacity, as evidenced by increased exercise tolerance and higher levels of physical activity. In addition, CR has been associated with significant improvements in QoL, including better mental health and reduced symptoms of depression and anxiety[56-58]. Participation in CR also correlates with lower rehospitalization and mortality rates, highlighting its importance for long-term postoperative care[59,60]. By incorporating lifestyle changes and stress management techniques, CR programs enable patients to take an active role in their recovery, resulting in sustainable health benefits and improved long-term outcomes.

Cardiac shock wave therapy (CSWT) has been explored as a therapeutic option to enhance recovery after cardiac surgery. It involves noninvasive treatment using acoustic waves to stimulate tissue healing, reduce pain, and improve blood flow[61]. Some studies have suggested that CSWT helps alleviate postoperative pain, improves mobility, enhances cardiac function, and potentially improves QoL[62]. The combination of CSWT with standard medical treatments has been shown to significantly reduce the risk of rehospitalization, thereby improving long-term patient outcomes[62]. By integrating CSWT into the rehabilitation process, healthcare providers can offer a more comprehensive approach to managing severe coronary artery disease, leading to better patient recovery and reduced healthcare costs.

FUTURE RESEARCH DIRECTIONS

Future research should focus on how big data and artificial intelligence (AI) can predict patient recovery and rehabilitation outcomes[63,64]. AI models can analyze large datasets, including patient demographics, surgical types, comorbidities, and recovery metrics, to identify patterns and personalize CR programs. Additionally, exploring the role of telemedicine in enhancing patient adherence and engagement is essential. Research could investigate the use of remote vital sign monitoring, virtual consultations, and digital platforms that guide patients through rehabilitation exercises at home[65,66]. These innovations have the potential to improve accessibility, monitor progress in real-time, and enhance long-term outcomes for diverse patient populations, especially those with heart failure[67-69].

CONCLUSION

Several challenges remain in optimizing postoperative outcomes. Variations in accessibility and adherence rates of CR programs may impact the consistency of observed benefits across different patient populations. In addition, personalized CR approaches considering individual patient characteristics and comorbidities are critical to maximizing the effectiveness of these programs. Future research should focus on identifying biomarkers that predict response to CR, developing more targeted interventions, and exploring the integration of technology such as telemedicine and wearable devices to improve patient engagement and adherence. Expanding CR access and tailoring programs to the diverse needs of cardiac surgery patients, including those from underserved populations, will be critical to improving long-term health outcomes. In summary, CR is an important component of postoperative care and significantly improves QoL and functional capacity. Continued research and innovation in CR delivery and personalization will be critical to further improve long-term outcomes for cardiac surgery patients.