Signs of malnutrition and inflammation may help predict complications in microvascular flap surgery

Anaesthesiologist and intensive care physician Rihards Pēteris Ročāns, in his doctoral thesis “Biomarkers for predicting complications in microvascular flap surgery” focused on how routinely available laboratory indicators can help identify the risk of complications in patients after complex reconstructive microsurgery. The idea for the study arose from the observation that blood test data already collected during treatment are often not used in a sufficiently targeted way – especially in situations where timely risk recognition can be crucial for treatment outcomes.

From routine tests to more accurate prediction of complications

Free flap microsurgery, or the transplantation of tissue flaps, is one of the most complex methods in reconstructive surgery. It is used in patients who have extensive tissue defects following trauma, oncological surgery, infections or other health conditions. During the operation, tissue together with its blood vessels is moved from one part of the body to another and connected to a new blood supply with microscopic precision.

Although microsurgical technologies have advanced significantly in recent decades, complications remain a serious problem. In the most severe cases, the transplanted flap may lose its blood supply and fail. Even seemingly minor complications can cause infections, require additional surgery and considerably prolong recovery time.

This is why the aim of Ročāns’ research was to determine whether data from routine laboratory tests can help predict the risk of complications before surgery and enable doctors to act in good time.

Four clinical studies to understand signs of complication risk

The research was carried out in several consecutive stages. First, Ročāns conducted an extensive literature review, analysing 80 international scientific studies. This made it possible to identify areas that could be particularly important for further research into the prediction of complications: the patient’s nutritional status, inflammatory processes and blood coagulation indicators.

The literature review was followed by four prospective clinical studies, in which several hundred patients who had undergone microvascular tissue transfer surgery were analysed. In each study, the researcher assessed a different group of biomarkers and their association with postoperative complications or the risk of loss of the transplanted tissue.

In the first study, which assessed nutritional status, the CONUT index was used and 72 patients were included. In the second study, the researcher analysed the fibrinogen-to-albumin ratio, or FAR, in 130 patients, while the third study assessed von Willebrand factor antigen (vWF:Ag), which is associated with blood coagulation processes, in 88 patients. The fourth study, involving 173 patients, focused on transforming growth factor beta-1 (TGF-β1), which can be used in postoperative risk assessment.

A particular value of the research is that many of the biomarkers analysed in the study had previously been investigated very little, or not at all, in microvascular flap surgery.

Nutritional, inflammatory and coagulation indicators as a basis for predicting complications

The results of the study suggest that some complications could potentially be prevented even before surgery. If laboratory indicators point to malnutrition or chronic inflammation, doctors would have the opportunity to provide nutritional therapy, adjust treatment and monitor patients more closely in good time.

Importantly, some of the biomarkers used are already available in routine laboratory tests. “It does not actually cost anything extra, because these tests are already performed for the patient,” the researcher emphasises, referring to the use of routine blood tests to predict complications.

One of the most striking findings was the importance of nutritional status. The results showed that patients with signs of malnutrition were more likely to develop postoperative complications. “Malnutrition is a known risk factor in surgery, but we still cannot fully explain why its impact is so pronounced in this case,” says Ročāns.

The results regarding the fibrinogen-to-albumin ratio were equally interesting. It emerged that the risk of complications increases not only when this indicator is too high, but also when it is too low. This means that what matters for the patient is not the absolute level of a single indicator, but the balance between the two. Von Willebrand factor antigen, in turn, helped to identify more accurately patients with an increased risk of thrombosis. The researcher found that higher levels of this biomarker were associated with more pronounced inflammation and a greater likelihood of flap loss.

TGF-β1 also proved particularly promising. It is measured after surgery, and an elevated level may signal emerging blood circulation problems even before clinical symptoms appear.

Although the doctoral thesis has produced several practically significant results, the author himself considers it only a beginning. He hopes that future studies will help to better understand the mechanisms of the identified biomarkers and find even more effective ways to prevent complications. “I think we have moved the field forward. Doctors will now have more information on what to look for in blood tests and to what extent,” says Ročāns.

The doctoral thesis is closely related to predicting complications in reconstructive microsurgery; however, Ročāns notes that his own clinical specialty is anaesthesiology, in which he also wishes to continue his professional work.

Summary of Rihards Pēteris Ročāns' doctoral thesis in the RSU e-resource repository