ADVERTORIAL: Cath lab technologies for medicine in the precision age

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This advertorial is sponsored by Siemens Healthineers

In the modern cath lab, having a suite of tools to treat coronary artery disease all the way through the patient journey is key to optimising outcomes among an increasingly diverse population of patients.

In this advertorial, Cardiovascular News speaks to three interventional cardiologists—Daniel Duerschmied (University Hospital of Mannheim, Mannheim, Germany), Joost Daemen (Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands) and Francisco Fernández-Avilés (Hospital General Universitario Gregorio Marañón, Madrid, Spain)—all of whom offer different perspectives on how new technologies are shaping their approach to care in the modern age.

For Duerschmied, having access to non-invasive technologies for the diagnosis and risk-stratification of coronary artery disease patients is of paramount importance. “It is critical not to subject the patient to further risk that is not necessary,” he tells Cardiovascular News. “That is one of the primary goals of being a doctor: do what needs to be done but do not do harm.”

That is where technologies such as coronary computed tomography angiography (cCTA) have become a vital component in his practice. “At present, we use CT according to risk prediction,” he explains. “We either decide to have patients transferred to the cath lab for direct invasive coronary angiography followed by PCI [percutaneous coronary intervention], or have examination by a CT, non-invasively to exclude coronary artery disease.”

There are many cases in which cCTA is essential, he notes, including patients with chronic coronary symptoms, but there are limitations—including for example, when heavy calcification is present. “We see a lot of patients with calcifications, due to which we are not able to tell whether the degree of stenosis is severe or not significant and if this lesion needs to be further treated via by a PCI for example,” he says. “So, this of course, is a limitation.”

The presence of blooming artifacts when using CT in severely calcified vessels, which can distort the overall picture of the level of calcification, is a big challenge in clinical practice, Duerschmied says. He uses the example of a patient who may be typical of those he sees regularly in practice, describing a middle-aged male, who would be considered at high-risk due to being a smoker, presence of arterial hypertension and dyslipidaemia, with elevated LDL cholesterol.

“Imagine the patient coming to me and reporting his symptoms. I then transfer him to CT and then he comes back with an image with heavy calcification, [with] blooming artifacts. I cannot really tell whether his symptoms are really related to his coronary artery disease, and I would still need to perform coronary angiography to decide on whether medical treatment alone would be sufficient, or whether stenting would be more adequate.”

These are all examples, according to Duerschmied, where new technologies are turning the dial. Among these technologies is the Naeotom Alpha (Siemens Healthineers), the world’s first photon-counting CT system. As part of the interdisciplinary cardiovascular imaging center together with the Department of Radiology and Nuclear Medicine Duerschmied’s institution began using the system —which uses cadmium telluride crystals, converting X-ray photons directly into electrical signals to overcome the loss of information encountered in conventional CT—since early 2022. The introduction of the new technology has been “very exciting”, he tells Cardiovascular News.

“The huge step forward is in spatial resolution,” he explains. In addition, Naeotom Alpha is also a dual source system (two tubes, two detectors, quite unique to Siemens Healthineers) which offers fast temporal resolution (66 ms) and this is needed to freeze cardiac motion. “The heart is a beating organ, that also moves due to breathing. So we have really sharp images that are quite impressive to see and to discuss with the patient.”

This is one element where the photon-counting system offers a truly unique experience for the patient, Duerschmied adds. “Just today, I was looking at images from a patient that had a previous stent implanted, and reported new problems. This has been a major issue before, but with the Naeotom Alpha, it has been easier to exclude stent thrombosis or in-stent restenosis in this patient, and it was quite convincing to show the images to the patient.”

This example demonstrates how Naeotom Alpha has changed the decision-making process, Duerschmied comments, noting that previously he would have opted to send the patient to coronary angiography, rather than opting for CT. The ability to offer a solution that exposes the patient to less harmful radiation is a “clear step forward”, he says.

The new system also offers benefits when it comes to heavily calcified vessels, adds Duerschmied. He says: “I know that before I would have just seen blooming and not been able to tell if this is severe stenosis or just minor narrowing with heavily calcified, but mostly externalised plaque.” Because of the increased spatial resolution, the blooming is already reduced compared to conventional CT. In addition, Naeotom Alpha brings another unique feature, called PureLumen. This application identifies just the calcium in the coronary arteries and simply removes it, letting physicians see behind the curtain of calcium.

Importantly, Duerschmied says, the technology offers new opportunities for clinical research and to improve diagnostics for patients in future, as well as opening doors to work more closely with colleagues in radiology.

“There are a number of completely new applications that this new technology brings to the table. For the first time, for example, we are thinking of using different contrast agents in one CT examination,” Duerschmied describes. “With photon-counting CT, we can part from the iodine-based contrast agents and also use gadolinium, which we usually only use for magnetic resonance tomography.”

Overall, the technology “will enable a huge step forward in research of coronary or cardiological imaging of the heart,” Duerschmied concludes.

vFFR: Making lesion assessment easier and faster*

When the decision is made that the patient should be transferred to the cath lab, this new cutting-edge technology on making lesion assessment easier and faster comes into play. Measuring fractional flow reserve (FFR)—evaluating the haemodynamic relevance of a coronary stenosis by determining the ratio between the maximum achievable blood flow in the diseased segment and the theoretical maximum flow under normal conditions—is one such step.

Traditional, invasive FFR includes the usage of a guidewire to measure pressure differences across a coronary stenosis. Drawbacks of this technique can include length of the procedure as well as potential discomfort to patients due to the administration of hyperaemic agents.

“There is a growing interest in physiological lesion assessment, however people refrain from doing it because of technical limitations and a perceived increase in cost,” says Daemen, principal investigator in the FAST (Fast assessment of stenosis severity) study programme, investigating the use of vFFR—a non-invasive, angiography-based method for calculating FFR values.

It is hoped that vFFR, which is derived from routine coronary angiography, could eliminate some of the drawbacks inherent in invasive FFR, as well as being a cost-saving, simpler approach. The technology requires two orthogonal angiographic projections that allow a 3D reconstruction of the vessel, combined with an input boundary condition for the pressure, which in this case is the aortic root pressure. Taken together these provide an instantaneous calculation of the vFFR over the specific segment of interest based on simplified computational fluid dynamics embedded in the algorithm.

The technology was validated first in the FAST I and FAST EXTEND clinical studies—retrospective single centre studies in which investigators demonstrated a positive correlation to invasive, pressure wire-based physiology, then in the prospective, multicentre FAST II study, comparing core lab-based vFFR assessment to invasive FFR.

“With FAST II we concluded that there was a very good correlation between vFFR and FFR as well as an excellent diagnostic accuracy in identifying lesions with an FFR below 0.80,” says Daemen. “We were able to report positive and negative predictive values, and sensitivity and specificity figures of 90%, 90%, 81% and 95% respectively.”

“Though FAST II adds to the growing body of evidence validating vFFR, there is still work to do to drive adoption of angiography-based FFR in the cath lab,” comments Daemen, who says there are three important components needed to change this picture. “One is the need for dedicated trials showing the superiority of angiography-driven physiology versus angiography-guided PCI, as well as studies that demonstrate the non-inferiority of angiography-derived FFR to conventional FFR or iFR.”

A second requirement is a need for consensus on the cost efficacy of the technology, and its impact on reimbursement models. Finally, says Daemen, the most important requirement is seamless connectivity between the angio-based FFR and fluoroscopy systems. “I think there is a huge interest in having everything seamlessly integrated, but the fact of the matter is that a lot of the technologies we use are third-party solutions,” he adds, noting that this is where the partnership between Siemens Healthineers and Pie Medical Imaging, developer of the vFFR software, bears fruit, allowing speedier integration into cath lab systems. The two companies together took a first step by launching QuantWeb vFFR, which offers vFFR integrated in the application software of the newest Siemens Healthineers imaging platform ARTIS icono.

The next step in the FAST study chain is the multicentre randomised outcome trial FAST III. Enrolment began in November 2021 involving 35 sites in The Netherlands, Ireland, UK, Germany, Italy, Spain and France, with an aim to include 2,228 coronary artery disease patients randomised 1:1 to either vFFR-guided revascularisation, or an FFR-guided strategy. Primary endpoints include a composite of all-cause death, any myocardial infarction, or any revascularisation at one year.

“The trial was set up as a non-inferiority trial, in which we hope to show non-inferiority of a vFFR versus an FFR-guided treatment strategy,” says Daemen. However, he adds, the interesting part of the study will be in the secondary endpoints, in which investigators will assess procedure times and cost.

“We notice that doing vFFR really makes the physiological lesion assessment easier and faster as compared to a hyperaemic, physiologically-guided invasive approach,” he comments. “We hope that the procedures will become shorter, and it could also be that we find differences in contrast usage and fluoroscopy time, because of the shorter procedures.”

Robotics: Medicine in the precision era

The combination of precision imaging, like the ARTIS icono imaging system, and new technologies, like the CorPath GRX Vascular Robotic System, is a symbol of the modern era of medicine, which is described by Fernández-Avilés. Not only does this offer healthcare providers with the opportunity to streamline the delivery of PCI procedures, but there are huge benefits in terms of the health and wellbeing of the cath lab team in adopting these technologies, he explains. “We are now in a precision medicine era, and in this era robotic management is particularly important in general medicine, cardiovascular medicine and in PCI,” Fernández-Avilés tells Cardiovascular News, adding that “high-quality imaging and the robotic precision, protection, and automation are essential for the treatment of our patients”.

According to Fernández-Avilés, robotic-assisted PCI presents a “clear opportunity” due to the structure of the coronary arteries. Since creating a robotic PCI programme in his own institution, which has been running since mid-2021, he comments that the safety features offered in terms of potential reduction in radiation exposure for the cath lab team, as well as the precision when stenting in combination with the integrated automated movements increase efficiency and prove to be very beneficial. “We realised that, in principle, there are no lesions which are not amenable to be treated with robotics, and that the benefits on the reduction of injuries derived from radiation are very clear,” he comments.

“Everybody knows that the cath lab is a dangerous workplace because of the deleterious effects of radiation. Young interventionalists in particular are facing a very long period of strong exposure to radiation with a clear risk of injuries which could include different types of tumours, degenerative diseases like cataracts, and also orthopaedic problems derived from the use of protective lead to avoid radiation,” Fernández-Avilés explains. “The possibility to perform robotic intervention in a remote way is one of the reasons why we decided to start the programme.”

Reflecting on his own experience of implementing a robotics programme in his practice, Fernández-Avilés comments that buy-in from the team, including interventional cardiologists, and also nursing staff, is the most important component, even before choosing the technology platform.

“In robotic PCI, the most important thing, the key of success, is the commitment of the team. Physicians need to realise the benefits of the change,” he explains, adding that nurses also play an important role.

“We started training a few doctors and nurses, first with simulators, then with animal models and then with patients, with the support of expert proctors,” he reflects. “This started with a small number of people and two nurses, each performing 10 procedures, and then we were certified and able to train the rest of the group. Now we have seven interventionalists able to perform complex robotic procedures, and we have all the nurses of the group, at least 15, able to assist.”

The CorPath GRX platform is intuitive and straightforward to use, according to Fernández-Avilés, who explains that, in his eyes, compatibility between the robotic unit and the angiographic imaging system are the fundamental elements of success in robotic PCI. The angiographic system should be a high-quality imaging system and should be capable of being manipulated outside the operating room in combination with the robot, he says.

“You can manipulate the guiding catheter and the guidewire, which is the most important part of the procedure, and you can advance different types of devices, including balloons, stents and other devices, by the manipulation of the three controls you have at the workstation,” Fernández-Avilés explains, describing the operation of the platform.

“These controls can be manipulated manually, or can be helped by automatic movements. There are five different automatic movements that help you with guidewire navigation, lesion crossing or anatomy measurement inside the coronary tree, and can help to navigate complex anatomies and severe lesions.”

Recent research by Campbell et al has shown that more than 60% of coronary lesions lengths are inaccurately estimated leading to suboptimal stenting and bad prognosis. A further strength of the robotic system is the accuracy of measurement that the platform enables, allowing the operator to precisely measure the length of the diseased anatomy and then to select exactly the length of the stent that this particular lesion needs, according to Fernández-Avilés. “This is very important because it reduces the number of stents you will need,” he says. Wiring assistance also helps to save time and resources during a PCI procedure, he says.

When you are pushing the controls of the robot, you can move your stent with a constant speed that you are not able to do manually, he adds. “This allows you to position the stent precisely in landing zone, exactly where you want, what is extremely important in complex situations, like ostial lesions or bifurcations.”

Though Hospital General Universitario Gregorio Marañón is a high-volume centre, performing more than 2,000 manual PCI procedures per year, Fernández-Avilés believes that there are benefits to be found in lower volume centres employing a robotic system. He explains: “In our experience, we need no more than five cases to be familiar with the robot. No more. I think that you can really improve efficiency by using the robot.”

Asked if he sees robotics as the future of PCI, Fernández-Avilés tells Cardiovascular News: “I think that you should not avoid robotic PCI if you have the possibility to do it.”

*Cases which can be assessed with vFFR are stable coronary syndrome and non-ST elevation acute coronary syndrome.

The statements by Siemens Healthineers customers described herein are based on results that were achieved in the customer’s unique setting. There can be no guarantee that other customers will achieve the same results.


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