Storage-induced change in platelet transfusion response evaluated by serial transfusions from one donor to one patient.

BACKGROUND: Storage of platelet concentrates (PCs) results in storage lesions with possible detrimental effects on platelet recovery after transfusion, which might affect their ability to prevent or arrest bleeding. The aim of this study was to compare the quality of PCs stored for 1 to 3 or 5 to 7 days by assessing the corrected count increment (CCI) after transfusion. To isolate the effects of storage time, we studied serial transfusions of PCs obtained from one donor and one donation, and transfused to one single recipient after storage for 1 to 3 days and 5 to 7 days. STUDY DESIGN AND METHODS: Platelets were obtained from one donor by apheresis, divided into two units (>240 × 109 platelets/unit) and stored for 1 to 3 and 5 to 7 days, respectively, before transfusion. The PCs were transfused on normal indications to patients undergoing treatment at the hematology ward. Platelet count was measured before and after transfusion. RESULTS: Thirty patients concluded the study according to the protocol. The mean storage time was 2.4 ± 0.7 and 5.7 ± 0.8 days for platelets transfused on Days 1 to 3 and 5 to 7, respectively. Storage for 5 to 7 days decreased the 1-hour transfusion response as compared to platelets stored 1 to 3 days, from a CCI of 17 ± 7 to 13 ± 5. Despite this decrease, 86% of the 5 to 7 days stored PCs resulted in a CCI above the cutoff value for a successful transfusion of 7.5, which was not significantly different to PCs stored for 1 to 3 days. CONCLUSION: Storage of PCs for 5 to 7 days only slightly altered the transfusion response.

In vitro function of platelets treated with ultraviolet C light for pathogen inactivation: a comparative study with nonirradiated and gamma-irradiated platelets.

BACKGROUND: During storage of platelet concentrates (PCs) replication of contaminating pathogens might occur, which can be prevented by various pathogen inactivation (PI) methods using photoactive substances in combination with ultraviolet (UV) light. A new method uses only UVC light for PI without photoactive substances. This study evaluates the in vitro function, including hemostatic properties (clot formation and elasticity), of platelets (PLTs) treated with UVC light. STUDY DESIGN AND METHODS: A PC with 35% plasma and 65% PLT additive solution (SSP+) was prepared from five buffy coats. Three PCs were pooled and divided into 3 units. One unit was used as a nonirradiated control, the second was a gamma-irradiated control, and the third unit was treated with UVC light. In vitro variables including analysis of coagulation by free oscillation rheometry were analyzed on Days 1, 5, and 7 of storage. Ten units in each group were investigated. RESULTS: Swirling was well preserved, and the pH level was higher than the reference limit (6.4) during storage of PLTs in all groups. Glycolysis and PLT activation were higher for UVC-treated PLTs but the clot-forming capacity was unaffected. However, immediately after UVC treatment, the clot elastic properties were slightly affected. Hypotonic shock response decreased immediately after UVC treatment but recovered partly during the storage period. CONCLUSION: UVC treatment affected the in vitro properties, but PLT quality and storage stability were well preserved for up to 7 days, and the in vitro hemostatic capacity of UVC-treated PLTs was only minimally altered. The clinical relevance of these changes needs to be evaluated in controlled trials.

In vitro properties of platelets stored in a small container for pediatric transfusion.

BACKGROUND: The quality of a platelet (PLT) concentrate (PC) is affected by the number of PLTs in relation to the size and gas permeability of the container. This study evaluates the in vitro function, including hemostatic properties (clot formation and elasticity), of PLTs stored in a container of standard or small size. STUDY DESIGN AND METHODS: PCs with 30% plasma and 70% PLT additive solution were prepared from buffy coats. Two PCs were pooled and divided into the following containers: 1 unit and ½ a unit into a 1.8-L container (reference container) and ½ a unit into a 0.45-L container (test container). In a second set of experiments » of a unit was stored in the reference and test containers. Swirling, PLT count, blood gases, metabolic variables, PLT activation markers, hypotonic shock response (HSR), and coagulation by free oscillation rheometry were analyzed during 7 days of storage. RESULTS: Swirling was well preserved and pH was acceptable (6.4-7.4) during storage of PLTs in both containers. Glycolysis and PLT activation were higher when storing ½ and » of a unit in the reference container and storage of » of a unit in the reference container resulted in the largest decrease in HSR. The clotting time was similar whereas the clot elasticity was slightly lower for PLTs when stored as ½ and » of a unit in the reference container. CONCLUSION: Storage of a low number of PLTs benefits by storage in a small container in terms of better maintained in vitro properties.

In vitro properties of platelets stored in three different additive solutions.

BACKGROUND: New platelet (PLT) additive solutions (PASs) contain compounds that might improve the storage conditions for PLTs. This study compares the in vitro function, including hemostatic properties (clot formation and elasticity), of PLTs in T-Sol, Composol, or SSP+ during storage for 5 days. STUDY DESIGN AND METHODS: Fifteen buffy coats were pooled and divided into three parts. PLT concentrates (PCs) with 30% plasma and 70% PAS (T-Sol, Composol, or SSP+) were prepared (n = 10). Swirling, PLT count, blood gases, metabolic variables, PLT activation markers, and coagulation by free oscillation rheometry (FOR) were analyzed on Days 1 and 5. RESULTS: Swirling was well preserved and pH acceptable (6.4-7.4) during storage for all PASs. Storage of PLTs in T-Sol led to a decrease in PLT count whereas the number of PLTs was unchanged in Composol or SSP+ PCs. PLTs in T-Sol showed higher glucose metabolism than PLTs in Composol or in SSP+. At the end of storage PLTs in T-Sol had higher spontaneous activation and lower ability to respond to an agonist than PLTs in Composol or SSP+. PLTs in all the PASs had a similar ability to promote clot formation and clot elasticity. CONCLUSION: Storage of PLTs in Composol or in SSP+ improved the quality of PCs in terms of better maintained PLT count, lower glucose metabolism, lower spontaneous activation, and improved response to a PLT agonist compared to PLTs in T-Sol. PLTs stored in the various PASs had similar hemostatic properties. These findings make Composol and SSP+ interesting alternatives as PASs.

Autologous platelets have no effect on the healing of human achilles tendon ruptures: a randomized single-blind study.

BACKGROUND: Animal studies have shown that local application of platelet-rich plasma (PRP) stimulates tendon repair. Preliminary results from a retrospective case series have shown faster return to sports. HYPOTHESIS: Autologous PRP stimulates healing of acute Achilles tendon ruptures. STUDY DESIGN: Randomized controlled trial; Level of evidence, 2. METHODS: Thirty patients were recruited consecutively. During surgery, tantalum beads were implanted in the Achilles tendon proximal and distal to the rupture. Before skin suture, randomization was performed, and 16 patients were injected with 10 mL PRP (10 times higher platelet concentration than peripheral blood) whereas 14 were not. With 3-dimensional radiographs (roentgen stereophotogrammetric analysis; RSA), the distance between the beads was measured at 7, 19, and 52 weeks while the patient resisted different dorsal flexion moments over the ankle joint, thereby estimating tendon strain per load. An estimate of elasticity modulus was calculated using callus dimensions from computed tomography. At 1 year, functional outcome was evaluated, including the heel raise index and Achilles Tendon Total Rupture Score. The primary effect variables were elasticity modulus at 7 weeks and heel raise index at 1 year. RESULTS: The mechanical variables showed a large degree of variation between patients that could not be explained by measuring error. No significant group differences in elasticity modulus could be shown. There was no significant difference in heel raise index. The Achilles Tendon Total Rupture Score was lower in the PRP group, suggesting a detrimental effect. There was a correlation between the elasticity modulus at 7 and 19 weeks and the heel raise index at 52 weeks. CONCLUSION: The results suggest that PRP is not useful for treatment of Achilles tendon ruptures. The variation in elasticity modulus provides biologically relevant information, although it is unclear how early biomechanics is connected to late clinical results.

Platelet quality after washing: the effect of storage time before washing.

BACKGROUND: Patients who have experienced anaphylactic transfusion reactions receive washed platelet (PLT) concentrates (PCs) where the plasma has been substituted with a PLT additive solution. This study compares the in vitro quality of PCs washed at the beginning of the storage period (Day 1) to PCs washed at the end of storage (Day 7). STUDY DESIGN AND METHODS: PLTs were prepared by the buffy coat procedure. Two concentrates were pooled and then split to obtain an identical pair of PCs. One of the PCs was washed with T-Sol on Day 1 and the other on Day 7 of storage. Swirling, blood gases, and metabolic variables were analyzed before washing. Analyses of surface expression of CD62P and coagulation by free oscillation rheometry (FOR) were performed before and after washing. RESULTS: pH was acceptable in all PCs. Washing on Days 1 and 7 increased the CD62P surface expression. The FOR variables clotting time and clot retraction were not influenced by washing on either day. Washing resulted in a decrease in the number of PLTs and the decrease was larger on Day 7 compared to Day 1. CONCLUSIONS: PLTs washed on Days 1 and 7 of storage are effected by washing in a similar manner. However, a larger loss of PLTs occurred during washing on Day 7.

The effect of gamma irradiation on the quality of apheresis platelets during storage for 7 days.

BACKGROUND: This study compares the quality of gamma-irradiated versus nonirradiated platelet (PLT) concentrates (PCs) during storage for 7 days as assessed by various in vitro methods. A new technique, free oscillation rheometry (FOR), which measures clotting time and coagulum elasticity, was also used to evaluate the PLT function. STUDY DESIGN AND METHODS: Single-donor PLTs were collected by apheresis technique (n = 20). The PLTs from each donor were divided into two PCs, one gamma-irradiated with 25 Gy and the other used as a nonirradiated control. Blood gases, metabolic variables, and swirling were analyzed from Day 0. Samples taken on Days 1, 5, and 7 were also analyzed for hypotonic shock response (HSR), P-selectin, and glycoprotein (GP)Ib expression by flow cytometry and coagulation by FOR. RESULTS: Swirling, HSR, and the percentage of GPIb-expressing cells were well maintained for 7 days of storage. pH was always within accepted range (6.4-7.4). Glucose decreased and lactate increased during the storage period (p < 0.05). P-selectin expression increased during storage (p < 0.05). The FOR clotting time remained constant, whereas the build-up of elasticity was slower after storage (p < 0.05). No difference was found between irradiated and nonirradiated PCs. CONCLUSION: The results indicate a well-preserved quality of gamma-irradiated apheresis PLTs during storage for 7 days as assessed by in vitro methods, with no difference compared to nonirradiated PLTs.

The quality of platelet concentrates produced by COBE Spectra and Trima Accel cell separators during storage for 7 days as assessed by in vitro methods.

BACKGROUND: The quality of platelet (PLT) concentrates (PCs) can be evaluated with various in vitro methods. A new technique, free oscillation rheometry (FOR), can be used to monitor coagulation properties of PCs and gives information on clotting time and coagulum elasticity. This study compared the quality of apheresis PCs produced by the COBE Spectra and Trima Accel cell separators (both Gambro BCT) during storage for 7 days with in vitro tests including FOR. STUDY DESIGN AND METHODS: Apheresis PCs were collected with the COBE Spectra (n = 10) and Trima Accel (n = 10) cell separators. Swirling, blood gases, and metabolic variables were analyzed on Day 0. Samples taken on Days 1, 5, and 7 were also analyzed for hypotonic shock response (HSR), P-selectin, and glycoprotein (GP)Ib expression and evaluation of coagulation by FOR. RESULTS: Swirling, HSR, and percent GPIb-expressing PLTs were well maintained for 7 days, whereas glucose decreased and lactate increased significantly during storage for both Spectra and Trima PCs. Percent P-selectin-expressing cells increased to the same extent in both types of PCs during storage. pH increased between Day 0 and Day 1 but then decreased. The clotting time remained constant throughout the storage period whereas the development of elasticity was reduced on Days 5 and 7 compared to Day 1 (p < 0.05) for both types of PCs. CONCLUSION: The results indicate that the PLT quality after storage for 7 days is well preserved, although activation of PLTs occurs during storage as assessed by in vitro tests. No difference in PLT quality was observed between Spectra- and Trima-produced PCs.