Pilot Study for The Tight-K Study
Research type
Research Study
Full title
PILOT STUDY for The TIGHT-K STUDY. Arrhythmias on the cardiac intensive care unit - does maintenance of high-normal serum potassium levels matter?
IRAS ID
212350
Contact name
Ben O'Brien
Contact email
Sponsor organisation
Bart's Health
Duration of Study in the UK
0 years, 11 months, 30 days
Research summary
Heart rhythm problems are common after heart surgery. These may be dangerous and keep patients in hospital longer. Many doctors believe giving patients potassium helps prevent these rhythm problems. However, there is no scientific evidence that such treatments work and they can be expensive and unpleasant for patients to take, and expose patients to additional risk. Many patients tell us that potassium treatments were the worst memories of their time in hospital after their surgery.
We want to do a pilot study of 160 patients which will be used to show feasibility for a large randomised controlled trial (Tight K) with 1770 patients. Successful recruitment of 160 patients over 6 months will show that the main trial can be completed on time and that it is possible to collect the complete data set for the majority of patients. It will also highlight any major safety issues.
The aim of the main Tight K trial is to investigate whether it is necessary to administer additional potassium to prevent heart rhythm problems after heart surgery. Maintaining potassium levels at the high end of the normal range is the current standard care for these patients.
In both the pilot and the main Tight K trials, half of the patients will receive this standard of care treatment. The other half will only be administered potassium if their levels drop below normal.
The patients approached for this study will be having coronary artery bypass surgery (CABG). Patients will be approached by a clinician or a member of the research team when they attend clinic before their surgery. If they are happy to take part, they will be asked to sign a consent form at a clinic visit or when they are admitted for surgery.
Patients who have given consent will be randomly allocated using a computer to a strategy of either having their potassium levels controlled as per standard care (the ‘tight’ arm) or when they drop below normal levels (the ‘relaxed’ arm).
There will be no difference to the normal standard care leading up to the CABG procedure, or during the CABG procedure itself.
Immediately after their operation patients will be admitted to intensive care. The trial treatment period begins upon admission to intensive care. All patients will have their potassium levels monitored as usual. Patients in the ‘tight’ arm of the trial will have normal standard of care treatment. This will involve maintaining a level of potassium in the blood of at least 4.5mM/L. Patients in the ‘relaxed arm will only receive additional potassium if their potassium levels drop below the normal level, which is 3.6mM/L.
Local care teams will decide how to supplement potassium according to their normal local practice.
Patients will be monitored for episodes of rhythm problems in their heart. These rhythm problems are called atrial fibrillation (AF). Patients will wear a device (which weighs about 14 grams) called a holter monitor which will record their heart rhythm. It is attached to the patient’s chest using special stickers, similar to the ones used when having an ECG.
Any patient in the ‘relaxed’ arm of the trial that has an episode of AF lasting longer than 30 seconds will be treated according to standard care from that point onwards.
Following discharge, patients will be followed up by a member of the research team 28 days after their surgery.
REC name
London - Camden & Kings Cross Research Ethics Committee
REC reference
17/LO/0318
Date of REC Opinion
13 Mar 2017
REC opinion
Favourable Opinion