Technical FAQ: Anticoagulants, 12s Campagnolo cranks on 11s drivetrain

In this week's Technical FAQ, Lennard Zinn discusses riding while on anticoagulants.

Photo: Getty Images

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Dear Lennard,

For my 60th birthday, I was handed a DVT and “multiple” PEs, which got me a slow trip through the ER, and now a lifetime on anticoagulant. The symptoms were identical to ones I had experienced multiple times before but had passed off as a muscle tear in my left calf, and I’d been diagnosed (on history) with exercise-induced asthma. The asthma drugs never did much, and when I finally got a spirometer, I saw no decrease in peak flow even when I was hyperventilating up hills. I’d never bruised visibly much or bled much when cut. I had never put two and two together until I had the hyperventilation and the muscle tear, and then my lower calf and foot swelled up. Then it was all too obvious.

I’m on Xarelto, and I’ve both read the entire package insert and a bunch of the papers that have emanated from its use. It’s taken once a day with the evening meal. It is absorbed more effectively with food. It binds Factor Xa, a key protein in the fibrin net which forms at sites of damage and gives a scaffold for blood cells to bind to, forming the clot. Inhibit the fibrin net and inhibit the clot. The peak Factor Xa saturation occurs four to eight hours after the drug is taken, and by 12hrs there’s no free drug left in circulation. Since this is an equilibrium binding system, as the free drug is eliminated, the bound drug is also coming off its protein target, so at that 12hr point, a good deal of the bound drug has come free and been eliminated. So, by the time I get going in the morning, the risk of a bleeding injury is greatly reduced. In three years, I’ve not noticed any greater tendency to bruise or bleed, but I don’t tend to bash or cut myself between my evening meal and breakfast. But sometimes it does make me wonder if the drug is working well.

I used to race both bikes and cross-country skis but have ceased to do either. I still ride and ski plenty, but with the aim of enjoying the experience without getting too fit. And here’s the thing- the reason for taking the drug in the evening is that the window of peak effect takes you through the night, which is when heart rates are the lowest, which is the condition of greatest risk of clot. I have always had a low heart rate (max and resting) and racing and training for racing will bring my resting HR down near 40 (sitting) and who knows what in the middle of the night. That gap between heartbeats, as it extends, is when blood flow pauses and clotting can nucleate (it’s actually much more complicated than that because we’re actually forming and losing micro-clots all the time). I’ve been unable to find anyone qualified to give me professional advice on this, but I decided to try to keep my resting HR at 50 or above. It’s not that easy. There’s so much lovely snow right now, and so many pairs of racing skis in the basement. I think that being as informed as possible about the drug you are on gives you the tools to make an educated assessment of how to do the most with the least risk, or at least decide how much risk one is prepared to tolerate.

A lot of people know about “Economy Class Syndrome”, and might assume it’s an equal-opportunity malady, but that would be wrong. Apparently, 80-something percent of people who get it are classified as “athletic” or “fit”. And a surprisingly large percentage of those people are on their way to or from an athletic event. And that makes perfect sense- a population of people who keep their resting HRs low and have then pushed them even lower by “peaking,” then tapering, then getting on a plane. Or later, having raced and exhausted oneself, then spending a day or two in the host city and then getting back on the plane with the lowest resting HR you’ve ever had.

And I know compression socks are good, but calf sleeves…. The compression stops at the ankle, leaving blood free (or maybe even encouraged) to pool in the feet. It seems like a bad idea.

— Mike

Dear Mike,

The one time I had (multiple bilateral) PE (Pulmonary Embolisms) was from a DVT (Deep Vein Thrombosis) clot in my lower right leg or foot that moved to my lungs and created a constellation of small clots all around in them. It happened after the removal of a tight wrap around my right knee following surgery to clean out an antibiotic-resistant infection in it. The wrap had been on for a week or so due to the tendency for my knee to fill with fluid and swell up the instant it was removed.

I, too, have a low heart rate and low blood pressure, leaving me more susceptible. When I went to bed a few hours after the tight wrap had been removed, I couldn’t breathe. I was diagnosed with PE in the ER and had to spend the night in the hospital, where I was given an injection in the belly to dissolve the blood clots.

I was put on first Eliquis and then on Xarelto, both of which seem to work the same way. Here’s the third in a string of posts answering questions about it with links back to the previous ones. The bleeding dangers are real. Nobody told me to take it at night, and I would have felt more confident about not having a bad brain bleed in a bike crash if I had known the methodology of taking it with the evening meal that you describe. Maybe I should have read the long instructions that came with it…

On intercontinental flights, I wear full-length compression socks, from my toes to the tops of my thighs. I have plenty of them left over from numerous surgeries I’ve had. I also try to fly business class with the fully reclining beds going to Europe, as the flight is overnight, and I tend to be sleeping. I generally fly economy class coming back from Europe, as it’s daytime the entire time, and I tend to be awake and moving around.

― Lennard

Dear Lennard,

I just read your comment on VeloNews about Campagnolo 11-speed and 12-speed compatibility, particularly crankset compatibility.

Well since spring of this year, and with about 10,000 kilometers under my legs, I’ve used a 12-speed Super Record 53 x 39 / 175mm crankset on an 11-speed Super Record EPS system mounted on my Eddy Merckx Stockeu 69 (aka Ridley Helium SLX) and I’ve had no problems/issues at all. And that’s from a guy who has used Campy non-stop since 1974, with all its products’ ups and downs.

It’s interesting that your article’s photo uses a five-arm Campy crankset. When I (that’s me personally, not some “smart ass bike mechanic”) built up a C60 with SR EPS using the 5-arm crankset, it was quite common for the front derailleur to throw the chain off the 53 chainring. The 11-speed four-arm crankset solved that problem, and the 12-speed crankset follows in that it works great.

Needless to say, in my opinion, Campagnolo’s comments on such things as forward / backward compatibility, need to be taken with a grain of salt on occasion.

— Ted

Dear Jim,

I used Campagnolo pretty exclusively for about 25 years starting in 1995. As I aged and different standards came about (from 8 to 9 and so on to 12 and 52/42 through 53/39, compact and sub compact), I used many different configurations. The most recent of these were two different bikes with 11-speed Chorus groups (one road, one gravel) that I used with 12-speed Chorus 48/32 cranks. All worked well, as did a couple of different bikes in the past with 11-speed cranks on 10-speed groups.

— Lennard

Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder and purveyor of non-custom huge bikes , a former U.S. national team rider, co-author of “The Haywire Heart,” and author of many bicycle books including “Zinn and the Art of Road Bike Maintenance,” “DVD, as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”
He holds a bachelor’s in physics from Colorado College.

Follow @lennardzinn on Twitter

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