Gastrointestinal Bleeding After LVAD Implantation: Is It Predictable?

Abstract

Purpose Non-surgical bleeding (NSB) is one of the major clinical complications in patients under continuous-flow left ventricular assist device (LVAD) support. Previous studies showed an altered platelet receptor composition in response to increased shear stress and bleeding events in LVAD patients. We investigated if the platelet receptor composition of patients with bleeding complications differs from patients without bleeding complications prior to LVAD implantation. Methods Blood samples were obtained prior to LVAD implantation and at regular follow up-visits after LVAD implantation. The bleeder group consisted of 18 consecutive LVAD patients with postoperative NSB that were matched by age and gender with LVAD patients without NSB (non-bleeder group, n=18). Platelet receptor expression of GPIbα, GPIIb/IIIa, P-selectin and CD63 as well as intra-platelet oxidative stress levels were quantified by flow cytometry. Further we documented clinical characteristics, aggregation capacity and von Willebrand factor (vWF) diagnostic of all patients. Results Bleeders and non-bleeders were comparable regarding their age at study begin, gender, LVAD type, vWF antigen, vWF activity, vWF collagen-binding activity, and the aggregation capacity before and after LVAD implantation (p>0.05). LVAD patients in the bleeder group suffered from gastrointestinal bleeding (44%; n=8), epistaxis (28%; n=5), hematuria (28%; n=5), and from cerebral bleeding (11%; n=2). The analysis of platelet receptor expression showed that the percentage of P-selectin-positive platelets and the relative quantity of GPIIb/IIIa molecules on platelets were decreased in bleeders (GPIIb/IIIa: 26.900 ± 13.608 U; P-selectin: 7.2 ± 2.6%) compared to non-bleeders (GPIIb/IIIa: 36.259 ± 9.914 U; p = 0.024; P-selectin: 12.4 ± 8.1%; p = 0.016) prior to LVAD implantation. Conclusion In this pilot study, we observed a restricted surface expression of the two platelet receptors P-selectin and GPIIb/IIIa prior to LVAD implantation in patients who suffer from NSB during LVAD support. We hypothesized that P-selectin and GPIIb/IIIa may be suitable markers to identify patients at risk for LVAD-related NSB prior to LVAD implantation. Non-surgical bleeding (NSB) is one of the major clinical complications in patients under continuous-flow left ventricular assist device (LVAD) support. Previous studies showed an altered platelet receptor composition in response to increased shear stress and bleeding events in LVAD patients. We investigated if the platelet receptor composition of patients with bleeding complications differs from patients without bleeding complications prior to LVAD implantation. Blood samples were obtained prior to LVAD implantation and at regular follow up-visits after LVAD implantation. The bleeder group consisted of 18 consecutive LVAD patients with postoperative NSB that were matched by age and gender with LVAD patients without NSB (non-bleeder group, n=18). Platelet receptor expression of GPIbα, GPIIb/IIIa, P-selectin and CD63 as well as intra-platelet oxidative stress levels were quantified by flow cytometry. Further we documented clinical characteristics, aggregation capacity and von Willebrand factor (vWF) diagnostic of all patients. Bleeders and non-bleeders were comparable regarding their age at study begin, gender, LVAD type, vWF antigen, vWF activity, vWF collagen-binding activity, and the aggregation capacity before and after LVAD implantation (p>0.05). LVAD patients in the bleeder group suffered from gastrointestinal bleeding (44%; n=8), epistaxis (28%; n=5), hematuria (28%; n=5), and from cerebral bleeding (11%; n=2). The analysis of platelet receptor expression showed that the percentage of P-selectin-positive platelets and the relative quantity of GPIIb/IIIa molecules on platelets were decreased in bleeders (GPIIb/IIIa: 26.900 ± 13.608 U; P-selectin: 7.2 ± 2.6%) compared to non-bleeders (GPIIb/IIIa: 36.259 ± 9.914 U; p = 0.024; P-selectin: 12.4 ± 8.1%; p = 0.016) prior to LVAD implantation. In this pilot study, we observed a restricted surface expression of the two platelet receptors P-selectin and GPIIb/IIIa prior to LVAD implantation in patients who suffer from NSB during LVAD support. We hypothesized that P-selectin and GPIIb/IIIa may be suitable markers to identify patients at risk for LVAD-related NSB prior to LVAD implantation.