Cardiologists Can Perform Stroke Thrombectomy to Fill 'Unmet Need'

April 15, 2021

Cardiologists experienced in cardiac interventions can competently perform stroke thrombectomy after a short period of training, with comparable outcomes to those achieved by neuroradiology centers, a new study suggests.

"Using interventional cardiologists in this way will help address the huge unmet need for stroke thrombectomy that currently exists," senior author Petr Widimsky, MD, told Medscape Medical News.

Although this may be a feasible way forward in Europe, there is strong opposition to such a proposal from US neuro-interventionalists.  

The study, published in the April 12 issue of JACC: Cardiovascular Interventions, describes the establishment of a stroke thrombectomy program in University Hospital Kralovske Vinohrady, a large tertiary hospital in Prague, Czech Republic.

The hospital did not have a neuro-interventional program until 2012 when a joint program was started involving an experienced team of cardiologists, angiologists, and one interventional radiologist who trained the cardiologists on the thrombectomy procedure.

The current paper reports on the outcomes of the 333 patients with large vessel occlusion stroke treated under this program between October 2012 and December 2019.

The decision to perform catheter-based thrombectomy was made by a neurologist and was based on acute stroke clinical symptoms and CT angiographic findings.

Results show that functional clinical outcomes, assessed using the Modified Rankin Scale (mRS) score at 3 months, did not vary significantly across years 2012 to 2019, with a favorable outcome (mRS 0 to 2) achieved in 47.9% of patients.

Symptomatic intracerebral hemorrhage occurred in 19 patients (5.7%) and embolization in a new vascular territory occurred in 6 patients (1.8%), outcomes similar to those of neuroradiology centers.

The desired clinical results were achieved from the onset of the program, without any signs of a learning curve effect, they report.

"These findings support the potential role of interventional cardiac cath labs in the treatment of acute stroke in regions where this therapy is not readily available due to the lack of neuro-interventionalists," the authors conclude.

"Our main message is that our results were excellent from the beginning," Widimsky said. "When centers prepare properly, they can achieve excellent results from the beginning with cardiologists who are experienced in interventional procedures and who have spent sufficient time learning about the brain."  

The authors note that despite thrombectomy being an extremely beneficial treatment for severe stroke, many eligible patients remain untreated, largely because of a lack of neuro-interventionalists in many regions worldwide. They estimate that about 15% of all stroke patients are eligible for thrombectomy but only around 2% of stroke patients in Europe actually receive such treatment.

Widimsky, an interventional cardiologist himself, first thought of the idea of using cardiologists to perform stroke thrombectomies after a good friend and colleague suffered a severe stroke in 2010.

"This made us realize that our hospital needed to be more active in the stroke field," he said. "We decided that we needed to start doing stroke interventions."

But the major problem was the lack of neuro-interventionalists.

"There are not enough neuro-interventionalists in Europe. Interventional cardiologists can perform thousands of procedures every year whereas a neuro-interventionalist will at best perform hundreds a year. It is quicker and simpler to train the cardiologist to do it," Widimsky said.  

They hired one neuro-interventionalist to lead the program. "He was our tutor, he taught us his skills," Widimsky commented. "The cath lab is open 24/7, but if we only have one neuro-interventionalist we cannot offer a 24/7 service for stroke thrombectomy. But if we merge with cardiology then we can," he added.

Their hospital is a very busy center for myocardial infarction, percutaneous coronary intervention, and carotid stenting, he noted. "It is not difficult to make the step from that to stroke thrombectomy. Interventional cardiologists are used to performing carotid and coronary artery stenting. Stroke thrombectomy is a similar technique. The thrombectomy procedure is different to coronary angioplasty but it is not more difficult.  Actually, I think coronary angioplasty can be more difficult."  

Widimsky explained that cardiologists need to learn about the brain anatomy and physiology and learn the stroke imaging techniques. "I spent 1 month in the US learning stroke interventions working with simulators," he said. "I think interventional cardiologists can learn what they need to know in about 6 months. I would recommend they should watch about 50 procedures and perform at least 25 under supervision."

He believes this model is the way forward and hopes it will become routine. Thrombectomy is "tremendously effective" in improving outcomes in severe strokes, with a number needed to treat (NNT) of just 2.6 to prevent long-term disability in one patient, he said, while other procedures can have NNTs of 50 or more.  

"But millions of patients with acute severe stroke are not getting this life-changing treatment," he added. "We must do everything we can to make this service available to as many patients as possible."

Widimsky acknowledges that there has been opposition to this idea from the neuro-interventionalist professional bodies but this has lessened recently, at least in Europe. And a program that allows interventionalists with experience in extracranial carotid and vertebral endovascular procedures to "fast-track" technical training has now been proposed.

"There is an enormous unmet need for stroke thrombectomy in Europe, with some countries needing to increase the number of procedures done by 10 or 20 times. These include the UK, Sweden, Italy, Spain, and Portugal. This cannot be done without cardiology," Widimsky said.  

Editorial Strongly Supportive

An accompanying editorial, published alongside the current study, strongly endorses the idea of using interdisciplinary teams to deliver high standard stroke care.

Marius Hornung, MD, and Horst Sievert, MD, from CardioVascular Center Frankfurt, Frankfurt, Germany, point out that many experienced cardiologists are also trained in performing carotid artery interventions and are therefore experienced in accessing the supra-aortic arteries.

"To be able to guarantee optimized stroke therapy as soon as possible, disputes over competence among the individual medical societies involved must be ended," they write.

They advocate for the creation of interdisciplinary teams, with diagnostics, patient selection, and follow-up care remaining the core competencies and tasks of neurology; in addition, they call for appropriately trained and experienced physicians — regardless of their specialties — performing acute stroke interventions and endovascular thrombectomy.  

"Such a network must be installed as soon as possible to fulfill the mantra 'time is brain'…and not losing unnecessary time to patient transfer, or continuing to offer only the second-best therapy," they conclude.

Opposition in the US

Widimsky explained that this proposal may not be so applicable to the US, where the need for more clinicians capable of performing stroke thrombectomies does not appear to be as critical, possibly because vascular neurosurgeons as well as neuroradiologists are qualified to undertake these procedures.

Commenting for Medscape Medical News, J Mocco, MD, who is director of the cerebrovascular center, department of neurological surgery at Mount Sinai Health System, New York City, confirmed that this was the case.

"There is no legitimate data to support the claim that there is a lack of an adequate workforce to provide stroke thrombectomy, at least in the US," he said, adding that, rather, the primary limitation to patient access is a lack of adequate systems of care. "We should learn from the trauma model, which is strongly evidence based, and provide emergency stroke care in a similarly regionalized manner."

Mocco, who is also vice president of the Society of NeuroInterventional Surgery, was not impressed with the current study.

"This paper is a retrospective, single-center, unadjudicated, non-independent assessor case series and therefore, as the authors acknowledge in the limitations section of their paper, it is invalid to compare these data to the results from high-quality, prospective, core-lab, and independent assessor adjudicated randomized trials," he said. "The supposition that this trial provides evidence that the reported model should be widely considered lacks scientific rigor."  

Furthermore, "the interventional cardiology literature is replete with data regarding the importance of technical expertise and content knowledge," he added. "Why would that community now propose that such expertise and knowledge is not necessary for the brain?"

Mocco argues that the concept that interventional cardiologists should be fast-tracked to perform stroke interventions because they use similar tools, navigate blood vessels, and are comfortable working in critical situations, does not hold up.

"Liver surgeons and brain surgeons are both familiar with tissue manipulation, are used to operating in critical situations, and use cautery, scissors and scalpels; but no one would argue that a brain surgeon should be fast-tracked to perform liver surgery, or vice versa." 

He added: "Stroke patients do not have the luxury of choosing the physician who provides their thrombectomy. We should do everything reasonable to ensure that our systems of care are organized so that these vulnerable patients are treated by physicians who have appropriate knowledge and expertise." 

This study was supported by the Charles University Research program. The authors and editorialists have disclosed no relevant financial relationships.

 J Am Coll Cardiol Intv. Published online April 5, 2021. Abstract, Editorial

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