Without doubt, atrial fibrillation after cardiac surgery is the most common complication in 24.36% of our study population. This is definitely lower than in our previous study2 that reported an incidence rate of 28.7%. Nonetheless, this current study is still ongoing and the results will definitely change. What we anticipate even more eagerly is whether our prophylactic intervention using Tocovid, a tocotrienol-rich compound, would reduce the incidence of AF in the study arm.
It is also noteworthy that the increase in mortality rate and the length of stay in the intensive care unit and the total hospital stay, apart from the increased rate of reintubation, have remained almost unchanged over the years., This is despite advancement in post-operative care of cardiac patients. Consequently, in trying to alleviate this situation by providing a possible solution via prophylactic means, our project is intriguing. While we are unsure if our intervention would work, the scientific theory propelling our endeavour cannot be doubted. As Danish physicist Niels Bohr aptly puts it, “It’s very difficult to make predictions, especially about the future.”
We mentioned about the pathogenesis of POAF which is now thought to be due to oxidative stress and inflammation. Cardiac surgery itself inflicts a trauma on the heart, and the use of cardiopulmonary bypass produces ischaemic injury. Reperfusion injury that happens after an artery is grafted leads to oxidative stress and the production of pro-inflammatory molecules, resulting in leucocyte activation and the production of nitrous oxide and reactive oxygen species.60, It has also been demonstrated in human studies that a correlation exists between systemic inflammation and oxidative stress and the development of POAF., Guided by all this information, we ventured into this research project. If our hypothesis is proven correct, we would be able to reduce the morbidity and mortality associated with POAF together with the total time spent in ICU and the overall hospital stay – this alone would reduce the cost in patient management and lessen the strain on the healthcare system.
Research has shown that POAF was correlated with longer and costlier lengths of stay both in the ICU and also the total hospital stay, besides the rate of readmission.70,71, In the USA, these outcomes translate into a substantial financial impact amounting to approximately USD 2 billion per year39 out of a total expenditure of more than USD 6 billion related to AF care in the country.39,,, Despite the absence of any data either at the IJN of Kuala Lumpur or elsewhere countrywide regarding the total cost incurred in managing patients with this type of complication, it is predicted that the total costs would be huge if not monstrous. Hence, it is undeniable that improving the health condition of patients would have a positive effect on their economic activity, and subsequently, the national economy itself.
In devising ways to contend with this issue, we are fully cognizant of the fact that several non-drugs or non-pharmacological compounds have been used in the research to prevent POAF – namely polyunsaturated fatty acids (PUFAs), vitamin C, or a combination of vitamins C and E. While focusing on the non-pharmacological compounds, we noticed that as a known dietary antioxidant, PUFAs have been shown to confer potential benefits in reducing cardiovascular morbidity in animal models despite limited evidence for their use as prophylaxis for POAF. However, a very recent paper by Rubanenko O and Rubanenko A shows that patients treated with PUFAs had less activation of inflammation and oxidative stress after CABG, with a significant decrease in the prevalence of POAF after CABG. A 2017 meta-analysis of 19 randomised controlled trials (RCTs) found a reduction in POAF. Similarly, a 2018 meta-analysis that included 14 RCTs also showed a significant reduction of POAF with PUFAs as compared to controls, although this effect was found only in CABG, not valve surgery. It is very promising that an antioxidant had been shown to have an effect in preventing POAF, especially when our hypothesis is built upon a similar promise that tocotrienol-rich Tocovid, itself a powerful anti-oxidant, could ameliorate and prevent the occurrence of POAF.
Another compound which has been studied quite extensively is vitamin C, a compound known to reduce oxidative stress. In a 2016 meta-analysis of 7 RCTs, the incidence of POAF was found to be reduced as compared to controls. However, a more recent RCT involving 314 on-pump patients found to have no difference in POAF, ICU stay and the total hospital stay, and to date, there are still no guidelines referring its use for POAF prophylaxis. However, when we look at a combined antioxidants use where vitamin C is combined with vitamin E and PUFAs, a 2013 study showed that there was a significant reduction in the incidence of POAF among patients receiving antioxidants as compared to controls. It was therefore not surprising then when the authors recommended the use of a combination of these antioxidants as an effective, safe and cheap prophylaxis against the onset of POAF. However, until today, no guidelines reference of such a protocol is available.
Based on all the above-mentioned studies, it is highly likely that a powerful antioxidant and anti-inflammatory agent such as Tocovid might be able to mitigate the occurrence of POAF; this is exactly where this study might be able to pave the way in finding such a solution. While it is still too early to make any conclusion, the scientific basis to pursue such a study is well established and it will take a few more months before this study is concluded and the study groups unblinded.