Does it still make sense to publish papers on valve bioprostheses with a short-term follow-up?

The publication of the scientific results on the performance of bioprostheses is always susceptible to 2 potential sources of bias, partly linked to each other. First of all, there is a legitimate enthusiasm of scholars who ‘fall in love’ with the products they use and remain focused on the strengths of their new product in use. Second, scholars are driven by a desire to publish their results as soon as possible to attract the attention of the scientific community—often coupled with the need for an academic career. Obviously, to respond to and protect from the ‘attacks’ of the peer-review process and to get these data published, the positive results are highlighted while less favourable ones are ignored, such as the lack of long-term follow-up. An article with too many limitations would be rated ‘low priority’ by the reviewers, preventing the authors from reaching their central goal, i.e. to inform the scientific community of their study results so that the new device can also be used by others and benefit patients or, on the contrary, to warn or caution due to suboptimal, or at least not yet fully known, results.

With this consideration, we come to the second point: bioprosthetic valve devices are commercial products for which both the manufacturer and the buyer have interests. It goes without saying that the publication of negative results on a new device, for which huge economic, human and time resources have been invested for development and marketing, rarely if not never occurs in the scientific literature. This legitimate prudence of the initial evaluation of a product from multidisciplinary professionals—from the biological/veterinary to the bioengineering field—should not, however, deviate excessively from the opposite side in the advertising field; above all because these products are intended for human use and malfunctions are potentially life-threatening for the subject who is scheduled to receive the new device.

A new design, bio-material, chemical treatment, or implant system is labelled as ‘the revolution that has solved the problem’. Often, also, the article titles lead us to misinterpretations: ‘long-term follow-up’ should not be reported in articles where almost all patients reached 2–3 years of follow-up, less than a half 5 years of follow-up and only 2 or 3 patients 9 or 10 years of follow-up, maybe by telephone interview.

Finally, a publication that compares different devices for the same use enters a very ‘delicate’ area: it means enhancing one product over another if the results support it, and given the existence of tenders in the hospital environment based on these data, it results in a major scientific impact but also in an economic health issue.

In this context, the recent article by Werner et al. [1], which bravely compared 2 prosthetic models with different implant design and technique, ‘takes sides’ showing results that clearly demonstrate the advantage of one of these 2 models. Based on what was previously known—e.g. the negative results with the use of devices with leaflets mounted outside the stent, or the positive results recorded by the biological component of one of the 2 models using a ‘classic’ implant procedure, without a ‘rapid deployment’ implant system—the authors could simply meet expectations. Instead, we want to underline that if the authors had limited the analysis of their results to 2 or even 5 years of follow-up, no differences would have been found between the 2 prosthetic models.

It should therefore be emphasized that pre-clinical and clinical studies leading to the marketing of a new valve device are very rigorous and accurate but, by definition, they cannot promise anything either in the field of efficacy or, even more unfortunately, in the field of safety. Anyway, this is the price to pay for development: it is what has allowed, for example to enter the era of transcatheter aortic valve implantation that otherwise today we would not have and could not guarantee therapy to patients who, up to only a few years ago, were deemed inoperable and to be palliated by medical therapy.

It is therefore necessary to be resilient to the instinct to write that a new valve design, a new tissue or implant technique are the ‘final solution’ to the problem of structural valve degeneration, a subject on which scholars, academics and pharmaceutical companies have been studying and working for decades.

Therefore, regardless of advertising pressures, the average life expectancy of the Western world, to which we are referring for these considerations, is such that a biological valve device, before being defined as ‘revolutionary’ or at least better than the others, must guarantee as a primary objective better long-term durability. This does not mean delaying the marketing of a product, which would be impossible for industrial reasons, but the scientific community should be more prudent in publishing case series in which all patients do not have at least 5 years of follow-up. Will we be able to become more patient in the interest of our patients?

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