Rheumatic heart disease is a global problem affecting over 40 million individuals worldwide, causing over 300,000 deaths each year—outnumbering infectious diseases like HIV. This devastating disease primarily impacts young people, leading to 10.7 million years of life lost due to disability. Group A streptococcal infection ranks fifth in mortality among contagious diseases, with half of these deaths resulting from cardiac involvement. The REMEDY study indicates that 20% of cases were previously undiagnosed for rheumatic fever, up to 40% presented with advanced heart failure at diagnosis, and one in five patients died within two years of diagnosis. Rheumatic heart disease has a latency period of 10–15 years from pharyngeal infection to cardiac impact, so data likely reflect only severe cases, potentially underestimating the full scope due to undiagnosed subclinical cases.

Today’s study demonstrates that rheumatic valvulopathy remains significant, even in developed regions. Here, the authors aim to compare the long-term outcomes of mechanical and biological mitral prostheses in patients who underwent surgery for rheumatic mitral valve disease. Data from Taiwan’s national health system database (2000–2013) were analyzed, focusing on all-cause mortality and the need for reintervention as primary outcomes. Propensity score matching was employed to achieve homogeneous cohorts. Patients under 20 (15 cases), those with incomplete demographic data (4 cases), and those with mitral valvulopathy of other etiologies were excluded. The hypothesis was that mechanical prostheses would be used in younger patients, while biological ones would be chosen for older, comorbid patients. The authors were interested in determining the age threshold favoring one prosthesis over the other.

The study identified 3,638 patients with mitral valve replacement due to rheumatic disease. About 30% (1,075 patients) received a biological prosthesis, and 70% (2,563 patients) a mechanical one. Propensity matching yielded 788 homogeneous pairs. In-hospital mortality showed no significant differences. However, long-term outcomes favored mechanical mitral prostheses: 10-year actuarial mortality estimates were 50.6% for biological prostheses versus 45.5% for mechanical prostheses (HR 1.19, p < .05); reintervention rates were 8.9% for biological prostheses versus 0.93% for mechanical prostheses (HR 4.56, p < .01). Notably, mechanical prostheses showed a slightly higher stroke rate, though not statistically significant (28% vs. 29.4%). The survival advantage of mechanical prostheses was most pronounced in younger patients and remained evident in those up to 65 years old.

The authors conclude that, for patients with rheumatic mitral valve disease, mechanical prostheses are associated with favorable long-term outcomes in patients younger than 65 years.

COMMENTARY:

Choosing between biological and mechanical prostheses for either aortic or mitral positions is never a trivial decision. At the extremes of adulthood, the choice is straightforward: mechanical prostheses are advised for patients under 50, while biological prostheses are preferred for those over 70. The decision becomes more complex for the large patient cohort between 50 and 70 years of age. Here, life expectancy is a determining factor, heavily influenced by age and comorbidities. However, lifestyle considerations, adherence factors, and potential anticoagulation complications are also crucial. In fact, patient preference is key in prosthesis choice at any age.

In an era promoting patient empowerment, surgeons are responsible for providing the most current information to help patients clarify their preferences. A shared decision-making approach is recommended, discussing not only durability, anticoagulation regimens, reintervention rates (surgical or percutaneous), thromboembolism, bleeding, endocarditis, pannus formation, etc., but also lifestyle changes, pregnancy concerns for women of childbearing age, follow-up visits, and even the sound of the mechanical prosthesis. Innovations such as new-generation anticoagulants, On-X mechanical valves, and results from the PROACT and PROACT Xa studies must be mentioned. Physicians are responsible for guiding patients through an overwhelming information landscape to make a decision aligned with their needs.

Just as with different prostheses, this study has limitations as it relies on administrative data, lacking access to detailed clinical or surgical data, which prevents adjusting for rheumatic severity. Potential coding errors and the absence of echocardiographic follow-up data limit our understanding of bioprosthesis structural deterioration in reintervention contexts.

In conclusion, Chen et al.’s study supports the latest European and American guidelines regarding mitral prosthesis choice. Yet, the final decision must be individualized, as José Ortega y Gasset (a Spanish philosopher) said: “I am myself and my circumstances, and if I do not save them, I cannot save myself.”

REFERENCE:

Chen CY, Chan YH, Wu VC, Liu KS, Cheng YT, et al. Bioprosthetic versus mechanical mitral valve replacements in patients with rheumatic heart disease. J Thorac Cardiovasc Surg. 2021 Mar 18(21)00512-2. doi:10.1016/j.jtcvs.2021.03.033