CC Cardiol Croat Cardiologia Croatica Cardiol. Croat. 1848-543X 1848-5448 Croatian Cardiac Society CC 2020 15_3-4_59 10.15836/ccar2020.59 Extended Abstract Assessment of platelet function during transcatheter aortic valve implantation https://orcid.org/0000-0003-1762-9270OstojićZvonimir* https://orcid.org/0000-0002-9346-6402SamardžićJure https://orcid.org/0000-0002-3705-0226PavasovićSaša https://orcid.org/0000-0002-5631-0353ŠipušDubravka https://orcid.org/0000-0003-4519-5940ŠafradinIvica https://orcid.org/0000-0002-4721-3236Rešković LukšićVlatka https://orcid.org/0000-0002-3437-6407Šeparović HanževačkiJadranka https://orcid.org/0000-0001-5979-2346SkorićBoško https://orcid.org/0000-0001-9101-1570MiličićDavor https://orcid.org/0000-0002-1482-6503BulumJoško University of Zagreb School of Medicine, University Hospital Centre Zagreb, Zagreb, Croatia ADDRESS FOR CORRESPONDENCE: Zvonimir Ostojić, KBC Zagreb, Kišpaticeva 12, HR-10000 Zagreb, Croatia. / Phone: +385-91-8980-702 / E-mail: ostojiczvonimir@gmail.com 032020 15 3-4 59 59 18022020 22022020 2020 Croatian Cardiac Society KEYWORDS: aortic stenosistranscatheter aortic valve implantationplatelet reactivityantiplatelet therapy

Introduction: Recent studies described changes in platelet reactivity (PR) in days following transcatheter aortic valve implantation (TAVI).1 However, precise time course and duration of these changes have not been fully investigated. Aim of the study was to investigate PR changes during and after TAVI.

Patients and Methods: Study included 40 consecutive patients with severe and symptomatic aortic stenosis undergoing transfemoral TAVI procedure. Patients’ clinical characteristics were collected from medical records. All patients who did not have chronic dual antiplatelet therapy received loading dose of aspirin and clopidogrel (300 mg) one day before the procedure followed by their standard maintenance doses. PR was measured in seven time points: before start of procedure (T1), after heparin administration (T2), 10 minutes after valve implantation (T3), at the end of procedure (T4), and on 3rd, 6th and 30th postoperative day (T5-7). PR was measured using impedance aggregometer in response to three platelet aggregation agonists using ASPI, ADP and TRAP test.

Results: Mean patient age was 82.7 years with majority of patients being male 60% (N=25). All patients underwent successful transfemoral TAVI procedure using either self-expandable (N=25, 62.5%) or balloon-expandable valve. Mean postimplantation gradient was 9.97±4.44 mmHg. More than mild paravalvular regurgitation persisted in 2 (5%) patients. Values of PR in each tested time point are presented in Table 1. There was no significant difference in PR between T1 and T2. After the valve implantation significant reduction of PR in all 3 tests was observed. PR continued to decline on consecutive measurements, with lowest values reached on 3rd post-TAVI day (T5). On T6, value of ASPI test were not significantly different to the ones measured on T1, while values of ADP and TRAP test remained significantly lower. By 30th post-TAVI day PR values reached levels not significantly different compared to T1.

Results of platelet reactivity test using ASPI, ADP and TRAP test in tested time points.
T1 T2 T3 T4 T5 T6 T7 P
ASPI 22.97±23.01 19.17±19.61 10.36±11.60 10.23±11.38 9.71±10.68 15.28±17.32 20.97±21.26 < 0.001
ADP 40.46±23.68 33.11±20.45 24.15±14.07 22.18±12.63 14.95±8.59 27.81±17.96 33.11±23.60 < 0.001
TRAP 91.69±32.50 93.42±27.71 69.31±26.57 64.05±24.20 40.97±17.71 69.09±29.08 88.06±35.51 < 0.001
Values are presented in Units (U)

Conclusions: Presented results indicate that transfemoral TAVI induces transient decrease in PR regardless of the platelet activation pathway. Significant reduction of PR is observed 10 minutes after valve implantation with continuous decrease until 3rd day post-TAVI after which it is gradually increasing to pre-TAVI values.