Cardiovascular disease continues to be the world’s leading cause of death according to the World Health Organization. This has troubled the medical community and industry for decades. In an effort to improve the chances of survival, research investment has been focused on new technologies, diagnostic tools and therapies.
In 1977, Dr Andreas Grüntzig began a revolution in the treatment of coronary artery disease. He constructed the first balloon angioplasty device, which enabled a procedure known as ‘percutaneous coronary intervention’ (PCI). In this procedure, a balloon is inserted into the patient’s coronary artery and is inflated to clear a blockage: a stent is then placed to keep the artery open and help restore blood flow. PCI is now a routine part of treating coronary heart disease.
However, there are technical limitations to this procedure. “The intervention is performed under X-ray imaging guidance, which unfortunately presents geometrical limitations as it provides a two-dimensional picture of 3D coronary vessels”, says Egon Wülfert, Clinical Director EMEAI of Volcano Corporation, experts in the field of medical imaging and therapy.
Another problem is failures can lead to very serious problems: “The downside is that stent failures are associated with various negative clinical consequences, such as stent thrombosis”, says Wülfert. “Results from the largest prospective registry to date support the evidence that the use of intravascular ultrasound (IVUS), an imaging technology that is complementary to X-ray guidance in stent placements, could significantly influence clinical practice and were associated with a change in procedure strategy nearly three-fourths of the time for the benefits of the patients through better outcomes [Am J Cardiol 2014 Apr 15;113(8):1338-47].”
Average penetration of FFR and IVUS in Western countries
In light of this, Volcano has been developing its own technologies that may help alleviate some of these shortcomings. “Volcano is dedicated to developing diagnostic tools to enhance precision-guided therapy to overcome the shortcomings of the X-ray (angiogram) image and provide a holistic picture of the vessel that requires treatment”, explains Wülfert. “This has mainly been done through two complementary approaches: the fractional flow reserve (FFR) and intravascular imaging ultrasound modalities.”
These techniques are allowing the interventional medical community to obtain more detailed information than traditional angiogram images can provide. Wülfert explains: “In case the angiogram is showing unclear resolution, or haziness of a particular lesion in a single vessel or multiple coronary vessels, the FFR procedure can be used like a stress test applied directly on the catheterisation table. The miniaturised pressure sensor is mounted on a standard 0.014-inch wire and can be placed easily distal to the interrogated lesion. The measurement is performed under maximum hyperaemia to replicate an exercise stress test conducted through an injection of a vasodilator agent. There is a clear, validated, cut-off value, which indicates when the lesion should be treated or deferred.”
The IVUS technique gives physicians an incredibly detailed insight into plaque build-up in coronary arteries that was impossible to achieve with traditional methods. “The IVUS modality is camera-mounted on a catheter support with a diameter of less than 1.5mm. It provides a precise anatomical perspective from inside the coronary artery, with a 360° view. In addition to the traditional, high-resolution, grey-scale IVUS image, the virtual histology feature provides colour-coded information to characterise the nature of the plaque; it is thus possible to recognise a stable plaque or a risk of plaque rupture.”
Slow take up
Wülfert says the advantages of these techniques for physicians are many, but neither has seen the sort of adoption within the medical profession that will transform the industry: “The FFR is a surrogate for a stress test and is routinely used to confirm the appropriateness of the treatment of choice. IVUS is complementary as it provides anatomical information to guide the stent implantation through accurate vessel measurement.
Despite the large documentation of clinical evidence and known benefits of these two diagnostic tools, their adoption remains limited, with around six percent penetration on average in European countries.
“The FAME I (2009) [N Engl J Med 2009 Jan 15;360(3):213-24] and FAME II (2012) [N Engl J Med 2012 Sep 13;367(11):991-1001] studies have shown FFR-guided procedures provide superior clinical results, and are also cost-effective compared to angiogram guidance alone [Circulation 2013 Sep 17;128(12):1335-40]. Based on these two strong studies, the European Society of Cardiology has upgraded FFR as a technique in its clinical practice guidelines to the highest possible recommendation level to evaluate intermediate lesion and IVUS is recommended to guide the stent implantation.” Uptake has also increased in the US, where the procedures are being used to mitigate the risk of over-stenting.
Both FFR and IVUS offer attractive cost savings, says Wülfert: “At first glance there is an immediate additional cost for the FFR and IVUS devices, but if you take into consideration the mid and long term, most of the comparison studies show a clear clinical benefit and cost reduction in favour of FFR and IVUS. This is mainly due to the reduced need for re-intervention and risk of stent failure compared to the angiogram-only strategy.”
The ability to avoid such invasive surgery is attractive as it dramatically reduces the risks placed on a patient. “For a patient presenting three-vessel disease, FFR is associated with less stent implantation and may potentially save the patient from open-heart bypass surgery, which can impact irremediably on their quality of life.”
Getting healthcare systems to actually pay for the method is another matter. While some countries in Europe are willing to pay for IVUS and FFR devices, the lack of a unified healthcare system within the EU means some people are unable to access the treatment. “Some countries offer various methods and levels of reimbursement as they have recognised these benefits for the patient and the healthcare system. There is, unfortunately, no homogenous reimbursement policy across all the European countries, but we are seeing a slow but positive trend, with more consideration given to adopting a specific reimbursement for FFR and IVUS.”
Wülfert says Volcano is determined to keep innovating, while at the same time partnering with physicians who rigorously assess their products: “Volcano has a proven history of innovation through partnership with physicians to develop new tools to facilitate therapy guidance and make image interpretation simpler. The company offers the broadest physiology and imaging portfolio, designed to be used for daily clinical practice and research studies.”
Volcano has recently launched a new product that combines angiogram recordings with IVUS images: SyncVision, an online image processing workstation for coronary vessels that allows physicians to simultaneously navigate on both an angiogram and an IVUS image in a single correlated view. SyncVision is designed to combine the functionality of the angiographic road map with the precision of the intra-vessel IVUS image and simplify the procedure for interventionalists.
Moreover, Volcano also developed a new index known as the iFR (instant wave Free Ratio) Modality: an innovative technique designed to measure heart performance. It has been studied in more than 4,000 patients, cleared by the FDA, and installed in over 700 hospitals worldwide and 275 in Europe. “iFR avoids the use of a vasodilator agent, which simplifies the method of assessing the heart and facilitates a larger adoption of physiology assessment”, Wülfert explains. All this research is being done while making sure every new product is clinically trialled multiple times by a number of expert physicians.
With heart disease proving such a huge medical burden all over the world, it is encouraging that companies such as Volcano continue to innovate and make breakthroughs in the treatment of coronary heart disease. Ultimately, their work will help to improve the lives of patients around the world.