Vrijednost testova agregacije trombocita u procjeni paravalvularne regurgitacije nakon transkateterske ugradnje aortnog zaliska [Validity of platelet aggregation tests in the assessment of paravalvular regurgitation after transcatheter aortic valve implantation]

Ostojić, Zvonimir (2019) Vrijednost testova agregacije trombocita u procjeni paravalvularne regurgitacije nakon transkateterske ugradnje aortnog zaliska [Validity of platelet aggregation tests in the assessment of paravalvular regurgitation after transcatheter aortic valve implantation]. PhD thesis, Sveučilište u Zagrebu.

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Abstract

Transcatheter aortic valve implantation (TAVI) is a globally approved treatment method for patients with severe aortic stenosis (AS). Due to increased shear stress, these patients have disturbed platelet reactivity (PR). The aim of the research is to investigate whether successful TAVI corrects PR. The hypothesis is that there will be no change in PR in case of significant paravalvular regurgitation (PVR), due to persistent shear stress. The study included 40 patients with severe AS who underwent successful TAVI. PR was measured at 5 time points (2 before and 3 after the implantation) using Multiplate® analyser in response to three platelet aggregation agonists. The degree of PVR was determined using transesophageal echocardiography. Significant PVR was observed in 25% of the cases after initial implantation, and in 5% at the end of the procedure. Consecutive measurements of PR, revealed a significant reduction in PR in all three tests, 10 minutes after initial implantation, with continuous reduction in subsequent measurements. The lowest PR values were reached on the 3rd day after TAVI. The results indicate that a successful TAVI induces a decrease in PR, regardless of the platelet activation pathway. However, no association between PVR and PR has been observed, which is why PR cannot be used to asses PVR. These findings add new insights and new knowledge to understanding complex relations in intravascular milieu, following TAVI.

Abstract in Croatian

Transkateterska ugradnja aortne valvule (TAVI) priznata je metoda liječenja bolesnika s teškom aortnom stenozom (AS). Zbog turbulentnog toka krvi bolesnici s teškim AS-om imaju poremećenu agregaciju trombocita (AT). Cilj je ovog istraživanja ispitati dovodi li uspješan TAVI-zahvat do korekcije AT-a. Hipoteza istraživanja jest da neće doći do promjene AT-a ako nakon zahvata zaostane značajna paravalvularna regurgitacija (PVR) zbog i dalje prisutnog retrogradnog turbulentnog toka krvi. U istraživanje je uključeno 40 bolesnika s teškim AS-om kojima je uspješno učinjen TAVI-zahvat. AT je određivan u pet vremenskih točaka (dvije prije i tri nakon zahvata) koristeći tri agonista agregacije na uređaju Multiplate® analyzer. Stupanj PVR-a određen je pomoću transezofagusne ehokardiografije. Značajni PVR ustanovljen je u 25% slučajeva nakon inicijalne ugradnje, odnosno 5% na kraju procedure. Uzastopnim određivanjima AT-a utvrđena je značajna redukcija AT-a u svim trima korištenim testovima 10 minuta nakon inicijalne implantacije s tendencijom smanjivanja u naknadnim mjerenjima. Najniže vrijednosti AT-a dostignute su trećeg dana nakon TAVI-zahvata. Rezultati ukazuju na to da uspješan TAVI-zahvat uzrokuje smanjenje AT-a neovisno o putu aktivacije trombocita. Međutim, na opisane promjene ne utječe značajni PVR zaostao nakon TAVI-zahvata, zbog čega se testovi AT-a ne mogu koristiti za njegovu procjenu. Rezultati pružaju nov uvid i nova znanja potrebna za razumijevanje kompleksnosti intravaskularne okoline za vrijeme TAVI-zahvata.

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