Drug free technology to bring safer diagnosis for heart patients

The new Instantaneous Wave Free Ratio or iFR technique is used on patients with coronary artery disease to determine whether lesions or obstructions in their heart’s arteries are causing blockages to blood flow. Because iFR is drug-free, it is better tolerated by the patient compared with other methods used to diagnose cardiac problems.

TPCH Cardiology Director Professor Darren Walters says that a person with severe coronary artery disease may have several narrowing areas in their arteries, which block blood flow to the heart.

“If left untreated, this condition can result in a heart attack and potentially be fatal. iFR may help us determine whether narrowings in a patient’s coronary artery are actually causing significant blockages to blood flow,” Professor Walters says.

Not all patients with narrowed arteries will experience problems with blood flow to their heart, so accurate diagnosis is vital. The iFR method uses a pressure wire and a novel software algorithm that targets a specific point in a person’s cardiac cycle called the wave free period. The pressure wire is inserted via catheter in the wrist or groin.

“By determining the wave free period in a person’s cardiac cycle, the iFR can tell us whether the narrowings are causing blockages to the heart’s blood flow. Knowing if a patient’s coronary narrowings are causing blockages to blood flow, will determine what form of treatment is best,” Professor Walters says.

Some patients may be treated with drug therapy whereas others may require a coronary balloon and stent to physically open the artery. The trial aimed to validate iFR as equally accurate to other diagnosis methods without the need for drug therapy.

“If we can do this, this may lead to iFR becoming a standard clinical practice in treating patients with coronary artery disease. It will give us an effective
diagnostic tool for diagnosing and treating coronary artery disease and mean safer and more comfortable treatment for our patients,” Professor Walters says.

“The simple test can tells us which blockages really need stenting and which are best managed with medication alone. The technique is faster, safer and less expensive than other strategies to date. This is a significant advance in how we manage a common heart condition.”

The results of the trial, which recruited almost 2500 patients worldwide, found iFR to be excellent for determining management of moderate coronary
narrowings. They were presented at the American College of Cardiology meeting in 2017 and published in the New England Journal of Medicine.