Using wave intensity analysis to benefit patients with advanced heart failure
Novel and Emerging Technologies (NET) Grant – Dr Sern Lim, Queen Elizabeth Hospital Birmingham
Summary: This project will demonstrate whether a technique called ‘wave intensity analysis’ (WIA) can be used to assess the function of the right side of the heart. WIA may benefit patients with a range of heart diseases and be particularly useful in selecting those suitable for a mechanical heart pump, or for diagnosing and treating right heart failure.
Left ventricular assist devices (LVADs) are mechanical heart pumps that are designed to support a weak and failing left side of the heart. However, the right side of the heart must work well for LVADs to work successfully. Techniques that are currently used to assess the right side of the heart are inadequate which means it is difficult for doctors to select patients who would do well with an LVAD, or diagnose and treat right heart failure before it is too late.
When the heart beats, it generates a wave that propels blood into the bloods vessels. Wave intensity analysis (WIA) is a technique that measures the pressure and flow characteristics of these waves. By analysing these waves, we can work out how well the heart is pumping and how the heart interacts with the blood vessels. This project will show whether WIA can be used to assess the right side of the heart.
This project will include 20 patients with heart failure who are being assessed for heart transplantation or LVAD. As part of the routine assessment, patients will undergo a right heart catheter study to measure blood pressure in the lungs and right side of the heart, using a flexible plastic tube inserted into a vein. During the procedure, the researchers will insert a wire that can simultaneously measure pressure and blood flow to collect data for WIA. Patients with high pressure in the lungs will be treated with drugs to see if the pressures can be lowered.
The first part of the study will show whether WIA can detect changes in heart function and blood flow due to the drug treatment in patients with advanced heart failure before LVAD implantation. The second part of the study will assess the effect of changing LVAD pump speed on the right side of the heart. High pump speeds can worsen right heart function, and pump speeds that are too low may not be sufficient to support the left side of the heart. They will see whether WIA can be used to identify the best LVAD pump speed for each patient.
WIA can provide direct, high definition and almost real time assessment of the interaction between the right side of the heart and the blood vessels in the lungs. Better assessment of the right side of the heart would benefit patients with a range of heart diseases. For example, early deaths after heart transplantation are often related to failure of the (donor) right heart. In complex heart valve surgery and in patients with high pressures in the lungs, right heart failure is often very difficult to assess and manage, and a major cause of death. WIA may also have wider uses for monitoring heart function and treatment in very sick patients.