Department of Cardiovascular Sciences

Clinical trials

REVAKI-001: How using a drug called Sildenafil might prevent kidney damage after cardiac surgery

A known medicine, Sildenafil (Revatio®), is now being studied as a potential preventive treatment for serious kidney complications after cardiac surgery. Sildenafil is already available in the United Kingdom to treat erectile dysfunction (impotence) and a lung condition called pulmonary arterial hypertension. In this study, the amount of Sildenafil in your blood stream, and the way your body removes it during and after heart surgery will be investigated. Other aims of this research study are to find out how safe this medicine is in patient’s receiving heart surgery and which side effects, if any, it causes.


The aim of the study was to establish whether a known medicine, Sildenafil (Revatio®), could prevent damage to the kidneys during cardiac surgery. Kidney damage is a common complication of cardiac surgery and there is no current treatment. Sildenafil is already available in the United Kingdom to treat erectile dysfunction (impotence) and a lung condition called pulmonary arterial hypertension. In a previous trial (the REVAKI-1 trial) we identified a dose of sildenafil that was safe and resulted in blood levels that are known to be effective for the treatment of these other conditions In the REVAKI-2 trial we now want to compare the level of kidney damage in patients receiving the dose of Sildenafil identified in the REVAKI-1 trial compared to those receiving a placebo (a test substance).  We recruited 129 participants into the trial and found that sildenafil did not have any protective effects when compared to a placebo.

REDWASH: Investigating the damaging side-effects of blood transfusion after cardiac surgery

Blood transfusion may have unwanted side-effects that increase the risk of complications after cardiac surgery. We believe that this may be due to the microscopic particles released by the blood cells into the blood bag during storage. Currently these microscopic particles are transfused to the patient along with the donor blood. We want to establish whether removing these particles by washing blood cells immediately prior to transfusion can reduce the side-effects attributed to blood transfusion in cardiac surgery patients.

MARACAS: Looking at what causes kidney complications after cardiac surgery and the possible effects of Diabetes

A proportion of patients who have cardiac surgery are at risk of developing kidney complications after the operation. This study is looking at biomarkers (certain indicator substances) that are involved in causing these kidney complications to see if we have an indication of these developing earlier. If these complications can be identified straight after heart surgery they may be able to be prevented or treated in the future. We will also be trying to find out if having diseases like Diabetes have an increased risk of developing kidney injury after heart surgery. Recruitment is complete and now in the analysis stage.

p-MiVAKI Study: Preventing kidney damage in children after cardiac surgery

Cardiac surgery can lead to damage to the kidneys in more than 50% of children, especially newborns or very ill children. If they develop a kidney injury, they are at risk of additional complications such as the need for dialysis. Our research identified specific particles in the blood of adult patients undergoing cardiac surgery that may serve as early diagnostic markers of kidney damage. These are small particles called microvesicles and microRNAs that are released within hours of injury, and before kidney damage is established. Our research considered whether these microvesicles could work as good diagnostic markers or even as potential targets for future treatments in children who are at risk of kidney damage. Professor Gavin Murphy and Mr Attilio Lotto led this "feasibility study” which means that it is a small study that will help the researchers in the design of a larger one with many other patients." Following closure of this study a paper was written and published. Read the paper.

Ob-Card Study

The aim of the study is to establish whether being overweight or obese causes changes in the expression of genes in the heart that protect the heart from damage during surgery. Heart damage is common following cardiac surgery and there is no effective treatment. It is well known that patients who are overweight or obese are much less likely to develop severe heart damage during surgery and have better survival rates afterwards. This has been called the Obesity Paradox. We do not know why this occurs but our previous research in the laboratory suggests that being overweight or obese causes changes in gene expression that alter how heart cells use energy sources such as fat or sugar. This protects the hearts from damage. Our laboratory research suggests that this is regulated by changes in gene expression. We now want to establish whether these changes occur in cardiac surgery patients.


Patients with obesity undergoing heart surgery have lower rates of complications during and after their surgery compared to normal and underweight patients. We think this may be related to high energy diets that result in weight gain and potentially beneficial genetic changes. The PRE-OP ENERGY Trial aims to find out if a high energy diet before heart surgery will reduce complications following surgery. The trial is currently in active recruitment.


Val-CARD aims to answer the question “Does the drug sodium valproate reduce complications affecting the heart and kidneys in patients having heart operations?” Sodium valproate is a drug commonly used in the treatment of epilepsy. Recently it has been shown to protect against heart and kidney damage in laboratory tests. This has led to studies evaluating whether it can prevent heart and kidney damage in patients. We wish to evaluate whether sodium valproate can reduce levels of organ damage following heart surgery. We think that sodium valproate works by making the heart and kidney more resistant to any injury that results from the use of the heart lung machine.

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