Quality of Life in Patients Aged 60–65 Years Receiving Mechanical versus Bioprosthetic Aortic Valve Replacement

For patients with aortic valve disease, whether characterised by stenosis or regurgitation, aortic valve replacement (AVR) remains the primary treatment.^1,2 Surgical management options largely involve two primary prosthesis types – mechanical or bioprosthetic valves – each with distinct advantages and disadvantages. Mechanical valves, traditionally favoured for their durability, necessitate lifelong anticoagulation therapy, which can introduce bleeding risks and impose lifestyle restrictions. Bioprosthetic valves, in contrast, often spare patients the burden of continuous anticoagulation, but may have a higher likelihood of structural valve degeneration over time, potentially leading to repeat interventions.^3,4 Due to the distinct features of mechanical and bioprosthetic valves, the choice between the two has been a subject of debate for several decades. The durability and haemodynamic performance of the prosthesis significantly affect long-term outcomes.

Choosing between these prostheses can be particularly complex for patients aged 60–65 years, a demographic that bridges the conventional guidelines recommending mechanical valves for younger adults and bioprosthetic valves for older individuals.⁵ As life expectancy continues to rise, understanding how each valve type impacts longevity and long-term quality of life (QOL) has become an essential component of shared decision-making.

While clinical outcomes, such as survival and major adverse events, have been well-studied, there is comparatively less consensus on the subjective wellbeing and lifestyle implications following mechanical versus bioprosthetic AVR in this age group. Factors, such as the need for anticoagulation, the effective orifice area, valve noise and the potential for reoperation, can significantly affect a patient’s daily life. With advancements in bioprosthetic valve design and the increasing use of transcatheter valve-in-valve implantation, tissue valves are gaining popularity.⁶ However, it remains unclear whether they offer superior QOL compared with mechanical valves, particularly for patients who are suitable candidates for both types. In this study, we conducted a retrospective analysis of postoperative QOL in a borderline cohort for both valve types.

Methods

The study was approved by the Institutional Review Board of Beijing Anzhen Hospital. This was a single-centre retrospective study. We retrospectively reviewed patients who underwent isolated surgical AVR at our centre between January 2002 and March 2022. Patients aged 60–65 years at the time of surgery were selected for inclusion in the QOL analysis. We selected this age bracket because individuals in this group are typically considered candidates for both mechanical and bioprosthetic valve options during preoperative consultation. Baseline characteristics, echocardiographic variables and prosthesis-related information were collected through a detailed chart review. The size, type and brand of prostheses were extracted from operative notes or other available documentation. Additionally, prosthesis size was standardised according to body surface area. Only patients who underwent isolated AVR were included in the study, and those lost to follow-up were excluded.

The QOL was assessed using a cross-sectional telephone interview based on the 36-item Short Form Health Survey (SF-36). The original English version of the survey was translated into plain, simple Chinese and administered to patients in a standard Mandarin accent. During the survey, additional information regarding cardiovascular reintervention and cerebrovascular accidents was also collected. The telephone interviews were conducted by trained staff specialists from our institute’s Centre of Follow-Up. SF-36 scores were calculated following the method provided on the RAND website (https://www.rand.org/health-care/surveys_tools/mos/36-item-short-form/scoring.html).

Continuous data were expressed as medians with interquartile ranges and compared using the Mann–Whitney U-test, or as means ± SDs and analysed with an independent t-test. Categorical data are presented as frequencies and percentages, and compared using the χ² test. The effective orifice area was obtained from the manufacturer’s data or published literature. Subsequently, the effective orifice area index (EOAi) was calculated by dividing the EOA by the patient’s body surface area. For multivariable analysis of the total SF-36 score, we employed a linear regression model using the enter method to assess all relevant variables. Statistical analyses were performed using GraphPad Prism 8.0 (GraphPad Software) or IBM SPSS Statistics 25 (IBM).

Results

A total of 731 patients who underwent AVR between the ages of 60 and 65 years were followed, of whom 92 had died. As illustrated in Figure 1, there was no significant difference in long-term survival between patients with mechanical prostheses and those with bioprostheses (p=0.280). Of the 639 surviving patients contacted for the telephone survey, 11 declined participation. Therefore, 628 valid survey responses were collected, including 353 patients with mechanical valves and 275 with bioprosthetic valves. The mean follow-up duration was 7.3 ± 3.9 years. All patients were aged between 60 and 65 years at the time of surgery, with a mean age of 62.5 ± 1.7 years; 363 (57.8%) were men. Baseline characteristics are detailed in Table 1. Patients receiving mechanical valves were slightly younger and had smaller prostheses. Notably, the mean time of mechanical AVR occurred approximately 2 years earlier than bioprosthetic AVR.

The SF-36 survey scores are presented in Table 2. There were no significant differences in any of the QOL subitems between patients with mechanical valves and those with bioprosthetic valves. Accordingly, the weighted total SF-36 score was also comparable between the two groups. To account for potential confounding factors influencing QOL, a multivariable regression analysis was conducted. As shown in Table 3, BMI (β=−0.109; 95% CI [−0.854, −0.098]; p=0.014) and postoperative time (β=−0.251; 95% CI [−1.426, −0.683]; p<0.001) were the only independent predictors of QOL, after adjusting for age at operation, sex, ejection fraction, type of prosthesis, body mass index and effective orifice area index.

Since structural valve degeneration in bioprostheses typically manifests approximately 10 years post-AVR, we conducted a subgroup analysis including patients who underwent AVR 12 years earlier. As detailed in Table 4, there was a trend indicating superior performance of mechanical valves compared with tissue valves.

Other complications associated with the type of prosthesis were also evaluated. As shown in Table 5, no significant differences were observed in the incidence of cerebrovascular accidents, including ischaemic and haemorrhagic strokes, between the two groups. Additionally, there was no difference in the rates of cardiovascular reintervention, including redo AVR and transcatheter AVR. When adjusted for follow-up duration, the rates of stroke and cardiovascular reintervention per patient-year remained comparable between patients with mechanical and bioprosthetic valves.

Discussion

In this study, we investigated QOL following isolated surgical AVR in patients aged 60–65 years. No significant differences were found in survival or QOL between those receiving bioprosthetic valves and those with mechanical valves. Additionally, long-term complications, including cardiovascular reinterventions and cerebrovascular accidents, were comparable between the two groups.

These findings offer important insights for clinicians and patients when selecting an aortic valve prosthesis. These highlight several important considerations for patients aged 60–65 years undergoing AVR. While mechanical valves have traditionally been favoured in younger patients due to their durability and lower likelihood of structural valve degeneration, the trade-off involves the need for lifelong anticoagulation with warfarin. This requirement can lead to fluctuations in international normalised ratio, increased risk of bleeding and potential lifestyle restrictions – all factors that may adversely affect certain domains of QOL. Conversely, bioprosthetic valves, which do not typically require long-term anticoagulation, may afford patients greater freedom regarding diet and activity level. However, their limited lifespan, with potential valve deterioration over 10–15 years, can pose concerns about the need for reoperation or transcatheter interventions in the future.

Over the past decades, there have been significant advancements in bioprosthetic valves; however, their impact on long-term outcomes remains a topic of debate. Among these outcomes, survival is of paramount importance. Goldstone et al. reported that the relative risk of mortality following mechanical AVR and tissue AVR appeared to be similar for patients aged 60–65 years.⁵ Conversely, a recent study from the Mayo Clinic indicated that the long-term survival advantage associated with mechanical prostheses persisted until the age of 70 years.⁷

With the rapid development of transcatheter aortic valve implantation, the application of bioprosthetic valves in clinical practice has increased. For patients with specific indications for either mechanical or bioprosthetic valves – such as younger age and high bleeding risk – making a decision is often straightforward. However, for patients eligible for both types of valves, as in the current cohort, QOL following surgery may be the most critical factor in their decision-making process.

A small study involving sexagenarian patients demonstrated that those receiving bioprosthetic valves reported better QOL, as measured by the SF-36 questionnaire and the cardiac anxiety questionnaire.⁸ In younger patients undergoing mechanical AVR or the Ross procedure, health-related QOL was comparable between the two approaches, with mechanical valves not compromising QOL in comparison with homografts.⁹ This finding aligns with another study that indicated physical and mental performance after native valve-preserving surgery was comparable to that following prosthetic AVR.¹⁰

Another study examining patients younger than 65 years found no significant differences between bioprosthetic and mechanical valves regarding survival, clinical outcomes or QOL. In patients aged <60 years, although QOL was not inferior to that of healthy controls, the use of bioprosthetic valves was associated with a significantly higher incidence of reinterventions and major adverse cardiac and cerebrovascular events.¹¹

Lifetime use of anticoagulants following mechanical AVR and concerns regarding the durability of bioprostheses are major determinants of survival and QOL. Numerous studies have indicated that warfarin use is associated with reduced QOL, primarily due to various factors, such as fear of bruising and heavy menstrual bleeding.^12,13 Additionally, inadequate management of warfarin therapy can exacerbate these issues. Similarly, concerns about the potential need for redo AVR in patients receiving bioprosthetic valves may lead to increased anxiety and a subsequent decline in QOL. However, the advent of transcatheter valve-in-valve implantation may alleviate concerns related to the durability of bioprosthetic valves.

Patients may experience an improvement in QOL following AVR due to enhanced cardiac function. In individuals with aortic valve stenosis, this improvement is achieved through an increase in the aortic valve orifice area. However, in some patients post-AVR, a reduced effective orifice area may lead to prosthesis–patient mismatch. While some studies suggest that mild or moderate prosthesis–patient mismatch does not significantly impact QOL, other research has demonstrated a contrasting finding.^14,15 Studies have shown that a smaller indexed effective orifice area is significantly associated with impaired postoperative health-related QOL.^16,17 These findings highlight the importance of ensuring adequate valve sizing during aortic valve replacement to optimise long-term functional outcomes and patient wellbeing.

In the present study, we did not find a correlation between EOAi and QOL. This may be explained by the selection bias in this retrospective cohort. Generally, mechanical valves exhibit larger EOAs than bioprosthetic valves of the same size, which is particularly important in patients with small aortic annuli. In patients with small aortic annuli, mechanical valves are more frequently implanted, as evidenced by the prosthetic sizes reported in Table 1. This selection bias may counterbalance the effect of EOAi in the present study.

Additionally, our findings indicate that a higher BMI is associated with reduced QOL, potentially reflecting a lower EOAi. However, mechanical valves are also associated with some drawbacks, including operational noise. Several small studies have indicated that valve noise significantly affects QOL following mechanical valve replacement.^18–20 Interestingly, different mechanical valves produce varying sounds, which also significantly impacts postoperative QOL.^21,22 This aspect should be communicated to patients during preoperative consultations.

In the present study, postoperative time emerged as the only independent determinant of QOL in the multivariate analysis. Patients may experience a continuous deterioration in QOL following an initial improvement. A prior multicentre study indicated that older patients are at a higher risk of experiencing this decline.²³ Additionally, another prospective study found that functional decline or lack of improvement is common among older adults with severe frailty undergoing either surgical or transcatheter AVR.²⁴ This suggests that valve replacement is not a definitive solution as previously expected. Therefore, postoperative rehabilitation and ongoing cardiac care are essential for maintaining functional capacity and improving QOL after AVR.

In addition, adequate social support and general self-efficacy significantly influence long-term QOL.²⁵ It is essential to manage non-medical factors effectively to enhance overall QOL. Structural valve degeneration may also contribute to these findings in some patients. In the subgroup analysis presented in Table 4, the difference in QOL between mechanical and tissue valves becomes both apparent and statistically significant. Therefore, for patients with a longer life expectancy, discussions regarding long-term QOL following bioprosthetic valve implantation should be prioritised, despite the initially favourable performance of these valves.

This study is subject to several limitations. As a single-centre investigation with a finite sample size, the generalisability of our findings may be constrained, and longer follow-up is necessary to better evaluate both clinical outcomes and QOL trajectories over a more extended period. Patients in the present study were at varying postoperative times during follow-up, which could influence QOL outcomes, as indicated by the analysis. Furthermore, bioprosthetic valves were implanted approximately 2 years later than mechanical valves. This heterogeneity and imbalance in timing may have unknown effects on the results. Future research should also incorporate cost analyses and explore the impact of newer anticoagulants or advanced monitoring methods that may reduce the QOL burden traditionally associated with mechanical valves.

The follow-up period was relatively limited, potentially failing to capture QOL differences emerging >10 years after AVR, when bioprosthetic valves typically begin to exhibit structural degeneration. Notwithstanding these limitations, our results underscore the nuanced and multifactorial nature of the choice between mechanical and bioprosthetic AVR in patients aged 60–65 years. The interplay between clinical outcomes, patient preferences and evolving transcatheter solutions will continue to shape valve selection and, ultimately, patient quality of life.

Conclusion

In patients aged 60–65 years undergoing isolated aortic valve replacement, there is no significant difference in postoperative quality of life between mechanical and bioprosthetic valves.