02 Nov 2016
Latest company-backed trial finds superior outcomes when OCT imaging used in stent placement.St Jude Medical have confirmed the potential importance of OCT as a means to guide surgeons carrying out percutaneous coronary intervention (PCI) procedures, a widening of coronary arteries that have been narrowed by heart disease in which the artery is dilated from within.
Results from the Ilumien III trial were presented at this week's Transcatheter Cardiovascular Therapeutics Conference (TCT) in Washington DC. The study is said to be the first multicenter controlled comparison between OCT-guided PCT and alternative diagnostic imaging methods used by surgeons to assess key aspects of stent sizing and artery expansion.
Of particular importance was the ability of OCT to indicate the extent of stent expansion post-intervention. Increasing the minimal stent area (MSA) is a key factor in reducing stent failure, as well as ensuring appropriate stent expansion to restore blood flow.
In the trial, OCT was compared with two other techniques: the use of intravascular ultrasound (IVUS), which employs a specially designed catheter as an ultrasonic probe to image the tissues; and also with traditional angiography, the X-ray imaging of arteries after introduction of suitable radio-opaque contrast agents.
The study found that procedures guided by OCT resulted in comparable MSA to IVUS-guided PCI, and significantly better MSA than procedures using angiography. OCT also proved better than IVUS at detecting predictors of major adverse events such as stent malapposition, when the stent separates from the arterial wall.
Important imaging option
"Minimal stent area is widely considered the most important factor for circumventing both early and late major cardiovascular events," commented Ziad Ali of Columbia University Medical Center, principal investigator of the Ilumien III study.
"Now we know that OCT-guided PCI achieves similar MSA results to IVUS-guided PCI and results in significantly greater stent expansion compared to angiography."
Ilumien III employed St Jude Medical's Optis Integrated and Ilumien Optis PCI Optimization systems, alongside the company's Dragonfly imaging catheters. The Ilumien Optis platform combines intravascular OCT imaging with measurement of fractional flow reserve, or FFR, a guide wire-based method to measure blood pressure and flow through a specific part of the coronary artery.
When used together, FFR and OCT offer physicians a physiological and anatomical view of the coronary blood vessels to better diagnose and treat coronary artery disease, according to the company.
St Jude Medical launched the platform in 2012, having acquired LightLab Imaging - the company co-founded by OCT pioneer Jim Fujimoto - in 2010 for $90 million. St Jude was itself acquired by healthcare giant Abbott in a $25-billion deal announced in April 2016.
"These results demonstrate that OCT is an important imaging option to achieve optimal stent deployment to advance the care of patients with coronary artery disease," said Philip Ebeling, CTO at St Jude Medical, about the latest trials. "OCT has a superior resolution to detect predictors that can contribute to major adverse events and thus can facilitate the treatment of those conditions, if necessary, to minimize the likelihood of their occurrence."
Ilumien III follows two previous St Jude Medical-sponsored trials: Ilumien I was engaged with defining and evaluating OCT stent guidance parameters and determining the impact on physicians' decision making, while Ilumien II made a specific comparison between OCT and IVUS for assessing stent expansion.
The next trial to be supported by the company, Ilumien IV, is currently under development, and will involve a global multicenter evaluation of long term outcomes in patients randomized to angiography-guided PCI alone versus the use of angiography and OCT-guided PCI.