A weekend with the VScan : Part 2

So it does what it says on the can, and from an ergonomic point of view the VScan is a joy; it’s light, small, intuitive and user friendly. With the possible exception of battery life there seems little reason not to take it on the round.

But, and it is a big but, what is the point? Is this really good use of my time? Does it just look cool but achieve nothing? In short, are my patients going to get a better outcome if I use hand held echocardiography? These are all big questions and to be fair there is no way that I can do much more than even begin to address them. This is a blog, which after all is just unreferenced and shameless anecdote…

We used the VScan on 4 patients on the acute cardiology round. A mixture of clinical problems. What did we find?

Image quality

My view here has to be subjective because I don’t have another handheld machine to compare to. Comparison with a full function ultrasound cart would be like comparing apples and oranges. This isn’t a $250 000 ultrasound cart, but that aside, the 2D image quality is fair.

We used the machine four times in the CCU and the ED and in the patients we tried it on, who weren’t particularly challenging from an ultrasonic point of view, it was pretty easy to acquire useful views of the left heart structures from at least one acoustic window. The images were certainly adequate for assessing overall left ventricular systolic function, but there are no means of anything more than subjective quantification. A simple assessment of left valve morphology also seems quite feasible and in one case we appropriately identified significant aortic valve degeneration.

The images, for me at least, are a little dark and although display brightness is one adjustable parameter it didn’t seem to have a great effect. The gain setting is automated which is a drawback. Getting the workspace adequately lit helps but may be challenging given that the machine is likely to be used in an ambulatory setting (we had trouble getting low light at 1030am on Saturday morning in the ED.

Clinical Correlation

Much better publications than this one are now emerging on this question, so the reader is directed to these below.

However, anecdotally we felt that the VScan helped us to answer a few relevant clinical questions. I was confident reassuring one of my interventional colleagues about the absence of haemodynamically, significant mitral regurgitation in a patient who had undergone primary PCI for a STEMI and identifying new left ventricular dysfunction and severe mitral regurgitation in an oncology patient who had a normal echocardiogram two months ago. Significant aortic valve degeneration was accurately identified in another patient and wall motion abnormalities excluded in a chest pain patient in the ED. This covers all four patients that we scanned and all findings were subsequently corroborated on a conventional transthoracic study within 48 hours.

Where to now

It is intriguing now to consider where this technology is leading us.

As you can read from my comments, I am left in little doubt that this is a real and usable technical advance but it still leaves a whole lot of unanswered questions. I was surprised to find that Nelson Schiller, highly respected echo cardiologist from San Francisco, had written an editorial in the Journal of the American College of Cardiology, as far back as 2001 on Hand-held echocardiography; revolution or hassle?‘. His points were well made then although to have described the hardware then as hand-held was stretching the definition somewhat and since then the technology has moved on considerably in terms of miniaturisation and in other respects.

In cardiology practice I don’t think that the use of the device will be able to replace too many formal echocardiographic examinations (it didn’t in any of our patients) given that the data that is missing is perhaps greater than that acquired. Nevertheless, as a bridge to a formal study, for use out of hours and in unconventional clinical settings there is little doubt that hand-held echo can now start to find its niche.

Perhaps the biggest questions that will remain will be by whom and on whom this sort of machine can be safely and effectively used. The very favourable price point of this device will undoubtedly place this machine in many more hands than currently have access to full function echocardiography equipment, but this could be a double edged sword.  We have to remember that this machine will be used to image sick patients, in unfavourable surroundings and (to be fair) provides suboptimal and limited data. Add to that mix an inexperienced or untrained operator and the rest is obvious. We must be careful not to fall for some of the marketing hype; just because this machine looks like an iPod and costs about $10 000 doesn’t necessarily mean that accurate, cost effective and safe echocardiography has suddenly become a whole lot easier to deliver.

Conclusion

Paris, September 2011

Well with those last comments I can hear the knives being sharpened – yes, just another protectionist cardiologist looking after his patch…etc etc etc.

I’m very excited about this. I hope, and actually believe, that this really is the beginning of hand held echocardiography. I just hope it finds a good home. And remember it took Laennec over twenty years to convince the community to accept the stethoscope.

Links to Further Reading

The use of pocket-size imaging devices: a position statement of the European Association of Echocardiography. 

Diagnostic accuracy of a hand-held ultrasound scanner in routine patients referred for echocardiography – Prinz and Voigt – Abstract

The Future of Echocardiography – Tom Marwick

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