Correlation between ACT anD APTT during Transcatheter Aortic Valve Implantation and Chronic Total Occlusion Percutaneous Coronary Interventions

The choice of antithrombotic regimen during TAVI and CTO PCI includes the use
of unfractionated heparin. Heparin is the preferred anticoagulant drug in these
percutaneous cardiac interventions aiming for an ACT > 200sec or 250seconds
depending on the procedure.(1) Heparin has a short half-life time and can be
neutralized by protamine.(2)
Monitoring the use of unfractionated heparin during TAVI and PCI can be
performed with several measurements, like the ACT and aPTT. To measure ACT, an
activator is mixed with whole blood to provide a timing of haemostasis. aPTT is
a plasma test in which a surface activator is used to measure the time it takes
to form a fibrin clot.(2) In nearly every center ACT is the preferred method
(3) because of its ease of use and the assumed reliability.(4) ACT-guided
heparin regime during TAVI seems effective in minimizing major bleeding
events.(5)
There are limited studies focussing on the difference between ACT- and aPTT
measurements. The studies which investigated this difference are merely done in
patients with continuous heparin infusions, for example in the setting of
extracorporeal membrane oxygenation(ECMO). These studies suggest that there is
a better correlation between aPTT and dosage heparin than between ACT and
heparin. Also, the correlation between ACT and aPTT seems poor.(2, 6)
The accuracy and correlation of ACT with a point-of-care aPTT test for
monitoring the anticoagulation effect of unfractionated heparin has so far not
been done in the setting of percutaneous interventions. TAVI requires large
bore arterial access and is associated with a relevant frequency of access site
related bleeding and vascular complications.(7) CTO procedures often require
dual arterial access and the use of different strategies with multiple wires
which increases the prevalence of vascular complications, including pericardial
effusion.(8, 9)
Precise knowledge of actual anticoagulation during an invasive procedure and at
the time of access site closure may affect the incidence of TAVI and CTO PCI
related bleeding and vascular complications.
Therefore, the aim of the present study is 1) to compare point-of-care ACT with
point-of-care aPTT test and conventional aPTT test and 2) to correlate the
measured ACT, and point-of-care aPTT with any bleeding and vascular
complications during TAVI and CTO PCI.

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Primary Objective:
The aim of the present study is to find which point-of-care test (ACT or aPTT)
is superior in predicting bleeding complications within 24h after both TAVI
(Cohort A) and CTO PCI (Cohort B) procedure.

Secondary Objective(s):
The secondary objective is to find the correlation between the activity of
unfractioned heparin, the point-of-care ACT test and the point-of-care aPTT
test. The laboratory APTT test and factor anti-Xa assessment will be used to
further evaluate the activity of unfractioned heparin.

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A Single-center, prospective, observational study which will be performed in
two cohorts with their own challenges: Cohort A includes patients undergoing a
TAVI procedure and Cohort B consist of patients undergoing a CTO PCI.

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According to the Dutch Federation of University Medical Centers (NFU) the risk
for patients involved in this trial is very limited. Patients participating in
this trial only give an extra, small, amount of blood (2.7mL) from an already
available intravenous access. The intravenous access is standard of care during
both the TAVI and the CTO PCI procedure. Also, the use of heparin is standard
of care and the doses of heparin will not be changed due to this study.

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