I came across a Facebook post to
this research by the Department of Cardiac Surgery, Montreal
this is the so called "PROACT Trial"
As they say: " The ideal aortic valve substitute for young adults remains elusive "
it does
I have the following issues with it:
Problem 0: what is the point?
- No rational was listed on what problem was being solved? Nothing.
- No argument was made as to what possible benefits lay in being INR = 1.5 vs INR = 2.0
A loose argument is formulated: "
However, the impact of new bileaflet mechanical prostheses on the safety of lowering anticoagulation targets remains uncertain." ... Well except for the GELIA study done decades earlier ... just to name one.
The reader is left to speculate on this or there is an implicit "worry" about the monsters which are implied by this drive.
1:
Due to their durability, mechanical prostheses are more frequently used in young adults. However, these valves are thrombogenic, requiring lifelong anticoagulation which is mostly responsible for valve-related morbidity and mortality following mechanical AVR
this will not change by having a lower INR level and indeed if you're on 1.5 and miss a dose you have less safety margin (oh, but that doesn't fit our agenda, so lets not mention that)
2:
The Prospective Randomized On-X Valve Anticoagulation Clinical Trial (PROACT) aimed to evaluate the safety of lower anticoagulation (target INR 1.5–2.0) after implantation of the ON-X prosthesis in patients at high risk of thromboembolic events
but instead lets evaluate the safety of patients in LOW risk of thromboembolic events because apart from having a mech valve we'll exclude the others
3:
Concomitantly, all patients received aspirin 80 mg and were monitored using home INR testing.
so if you're going to use that protocol you'll need to be taking 80mg and monitoring at home.
4:
The mean follow-up was 3.8 years
whoopdie do ... that's not very long
5:
In terms of findings, the composite of major and minor bleeding, TE and thrombosis events was significantly lower in the test group (5.63%/pt-yr in the test group versus 8.47%/pt-yr in the standard group,
p = 0.046) (
Table 1).
which really isn't a significant amount with all the variables and I was unable to find what the INR was on those patients who had events when they had those events
they later go on to say: "
Interestingly, when comparing the composite of outcomes while excluding minor events, there was no statistically significant difference between the 2 arms ..."
6:
Five-year freedom from major or minor bleeding events in the test group (blue) versus the standard group (black) in the PROACT trial (from Puskas et al.8).
so 5 year freedom on a mean 3.8 year follow up ... sure ... no projections there
7:
The investigators concluded that, with the On-X prosthesis, a target INR between 1.5 and 2 translates into a lower incidence of bleeding events without a significant increase in TE events.
well of course it will reduce bleeding events but if the best they can say is in such a short term there was no significant increase (
note they do not say there was a significant decrease which they earlier mentioned in Point 5 above but must have decided to walk back as I observed in ) then whoopdi - do
so basically the protocol provides nothing except likelihood that in short term you may not have problems
8:
Secondly, as part of the study protocol, patients were provided a home INR monitoring kit and were closely followed up. This translated into the fact that out of >53,000 measurements, more than 60% of the measured INRs were within the desired range, with 96% of patients having at least one test per month.
wow ... 60% in range ... (facepalm-uck me)
9: they go on to distort the truth again
However, home INR testing is not widely adopted in the wider population because of availability and cost issues, and patient compliance with testing is overall lower in a real world setting15, which results in patients being off range a significant proportion of time.
so
- not widely adopted in the USA because of being allowed to type availability issues
- cost because of not being supported in the USA or people being short term minded
- patient compliance which yet again rears its head that the problem is the patients don't look after themselves
so like I normally say (and occasionally get slammed for it) ... if you are youner, want to have the best operational outcomes and are the sort of person who wants to take an active hand in it then get a mechanical valve and do your best with monitoring and testing and drug compliance.
if you're a bozo then get a tissue valve and join the reop shuffle over in the other room across the corridor
10:
Thirdly, while there was a reduction in anticoagulation-related complications in the low INR group, rates of major bleeding and neurological events (1.48%/patient-year and 1.98%/patient-year, respectively) remain comparable to previously published cohort studies examining long-term outcomes following mechanical AVR
so while they want to make a point that there is stuff all difference they want to make it clear that there was no significant long-term outcome benefits. "remain comparbel to previously published studies (like GELIA)
whatever floats your marketing boat I guess