Tag: heart valves

Categories : Cardiovascular Disease Implants and ProsthesesTags : Leave a comment

Mechanical Heart Valve Replacements have Better Long-term Survival

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Artificial heart valve. Credit: Scientific Animations CC4.0

Patients aged between 50 to 70 years with a mechanical heart valve replacement had better long-term survival compared to those with a biological valve, new research led by the University of Bristol has found. The study is published in the European Journal of Cardio-Thoracic Surgery.

The last two decades have seen an increase in the use of biological over mechanical heart valve replacements. However, while short-term clinical outcomes are known to be the same, long-term outcomes are still under debate.

Existing guidelines support the use of mechanical valves made of synthetic materials in patients below the age of 50, while biological valves made of animal tissue are favoured for those above the age of 65 or 70. The guidelines leave the choice to the decision of surgeons and patients who are 50 to 70 years old.

The research team wanted to find out the clinical outcomes for patients aged between 50 to 70 years undergoing elective and urgent heart valve replacement at the Bristol Heart Institute (BHI) over a 27 year period [1996 to 2023].

The researchers also sought to investigate trends, early outcomes and long-term survival rates, the incidence of repeat valve interventions and patient prosthesis mismatch (PPM).

A total of 1708 (61% male) patients with an average age of 63 years were included with 1191 (69.7%) receiving a biological valve replacement.

The research found there were no short-term differences when comparing patients receiving biological and mechanical valves. However, patients who received mechanical valves had better long-term survival up to 13 years after having surgery. 

Patients with a size 19mm biological valve replacement (a fairly small valve commonly used in females) had the worse long-term survival. Patients with a size 21mm mechanical valve had better survival compared to both size 19 and 21mm biological valves.  The study confirmed that severe PPM is a significant risk factor for poor long-term survival.

Gianni Angelini, BHF Professor of Cardiac Surgery at the Bristol Medical School: Translational Health Sciences (THS), Director of the Bristol Heart Institute and corresponding author, said: “Our study has implications for decision-making in surgical heart valve replacements for patients aged between 50 and 70 years old. The evidence supporting better long-term survival in patients receiving a mechanical heart valve suggests the current trend favouring biological valves in this age bracket should be urgently reconsidered. The survival benefit is especially clear in smaller sized valves.”

The research team recommends the evaluation of the long-term benefits associated with mechanical valves, especially in smaller sizes, despite long-term blood thinners not being needed with biological valves.

Study limitations

The single-institution design, retrospective collection of data, and absence of randomisation make the study open to bias. The lack of echocardiographic information could potentially underestimate the incidence of structural valve failure. In terms of repeat valve interventions, only patients who underwent re-do surgical aortic valve replacement or valve in valve transcatheter aortic valve implantation (TAVI) at the BHI were included.

As the BHI is a supra-regional centre, it is very unlikely that many patients might have undergone reintervention in other institutions. The cause of  death (cardiovascular/non cardiovascular) was not available.

Source: University of Bristol

Categories : Surgeries & ProceduresTags :

Earlier Valve Replacement Surgery Recommended in Aortic Stenosis

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Source: Pixabay CC0

Valve replacement surgery should be performed earlier than conventionally thought for people with aortic stenosis, as shown by new research published in the journal Open Heart.

Aortic stenosis is a common valvular disorder, especially in the elderly population, causing left ventricular outflow obstruction. Aetiologies include congenital (bicuspid/unicuspid), calcific, and rheumatic disease. Symptoms such as exertional dyspnoea or fatigue gradually develop after a long asymptomatic latent period of about 10 to 20 years. But many patients with aortic stenosis do not have symptoms even when they have severe narrowing of the valve and are thus not eligible for valve replacement.

The findings from this study show that these patients would benefit by undergoing a valve replacement – before they suffer irreversible heart muscle damage.

Lead researcher Prof Vassilios Vassiliou, from UEA’s Norwich Medical School, said: “The heart has four valves, which allow the blood to flow in one direction efficiently. With increasing age, one of the valves, the aortic valve, becomes increasingly narrowed or ‘stenosed’.

“A lot of patients with severe aortic stenosis do not have symptoms and therefore are not eligible for valve replacement according to the current guidelines.

“For these patients without symptoms, the guidelines suggest a ‘watchful waiting’ approach and intervention is recommended only when they show symptoms or develop pump failure.

“We wanted to know if it would be better to perform surgery and replace the valve sooner rather than later.”

In a systematic review, researchers compared early intervention versus conservative management in patients with asymptomatic severe aortic stenosis.

They then analysed data from all the available studies which involved a total of 3798 patients, out of which 302 were included in the two largest randomised controlled trials and 3496 in the observational studies.

Prof Vassiliou said: “We found that early intervention, before patients have symptoms, is associated with lower risk of death and hospitalisation for heart failure.

“By the time the patients develop symptoms, there has likely been irreversible damage to the muscle of the heart. This in turn may preclude a worse prognosis and adverse outcomes even after successful intervention.

“The timing of aortic valve intervention is crucial.

“We hope that our findings may herald the beginning of a change in the management of aortic stenosis patients, enabling the intervention to take place more commonly whilst the patients are asymptomatic.

“Ongoing trials investigating this high-risk population are anticipated to shed more light into the matter and in the identification of the optimal time of intervention,” he added.

Source: University of East Anglia