Viability and function of platelet concentrates stored in CPD-adenine (CPDA-1)

The effective use of CPDA-1 as an anticoagulant in routine blood banking practice requires demonstration that platelet concentrates prepared in this solution meet both in vitro quality control standards and maintain posttransfusion viability and function after storage. In this study of 138 units of CPDA-1 platelet concentrates, the average platelet count was 8.0 +/− 0.2 × 10(10) with 81 per cent of the units having greater than 5.5 × 10(10) platelets. The mean poststorage pH was 6.68 +/− 0.03 and only four of the units had a pH of less than 6.0 (3%). Residual plasma volume averaged 75 +/− 1 ml. Platelet viability was determined in 16 normal volunteers by measuring survival of 51Cr- labeled autologous platelets after storage for 72 hours at 22 +/− 2 C. Platelet recovery averaged 50 +/− 4 per cent, while survival was 7.3 +/− 0.4 days for the 15 units with a pH above 6.0. Measurements of posttransfusion platelet viability and function were made in 12 paients with thrombocytopenia secondary to marrow failure. Their mean pretransfusion platelet count was 17,000 +/− 2,000/microliter, and their standardized template bleeding times were all greater than 30 minutes. Platelet recovery averaged 44 +/− 5 per cent and survival 3.3 +/− 0.5 days. In seven of the patients with the best posttransfusion increments, bleeding time was improved. Five patients with poor posttranfusion platelet increments showed no improvement in bleeding time with CPDA-1; two of these patients were also transfused with CPD platelets and had no response. Our studies indicate that platelet concentrates prepared in CPDA-1 meet in vitro quality control standards and after transfusion, maintain viability and function comparable to that of CPD collected platelets.     

Platelets photochemically treated with amotosalen HCl and ultraviolet A light correct prolonged bleeding times in patients with thrombocytopenia

BACKGROUND: Photochemical treatment (PCT) with amotosalen HCl with ultraviolet A illumination inactivates pathogens and white blood cells in platelet (PLT) concentrates. STUDY DESIGN AND METHODS: In a Phase II crossover study, 32 patients with thrombocytopenia received one transfusion of PCT and/or one transfusion of untreated (reference) apheresis PLTs. Hemostatic efficacy was assessed with the cutaneous template bleeding time and clinical observations. RESULTS: Paired bleeding time data for PCT and reference transfusions were available for 10 patients. Mean pretransfusion bleeding times were 29.2 +/- 1.6 minutes in the PCT group and 28.7 +/- 2.5 minutes in the reference group. After transfusion of a dose of PLTs of at least 6.0 x 10(11), mean 1-hour posttransfusion template bleeding times corrected to 19.3 +/- 9.5 minutes in the PCT group and 14.3 +/- 6.5 minutes in the reference group (p = 0.25). In 29 patients receiving paired PCT and reference transfusions, mean 1-hour posttransfusion PLT count increments were 41.9 x 10(9) +/- 20.8 x 10(9) and 52.3 x 10(9) +/- 18.3 x 10(9) per L for PCT and reference, respectively (p = 0.007), and mean 1-hour posttransfusion PLT corrected count increments (CCIs) were 10.4 x 10(3) +/- 4.9 x 10(3) and 13.6 x 10(3) +/- 4.3 x 10(3) for PCT and reference, respectively (p < 0.001). The time to next PLT transfusion was 2.9 +/- 1.2 days after PCT transfusions versus 3.4 +/- 1.3 days after reference transfusions (p = 0.18). Clinical hemostasis was not significantly different after PCT and reference transfusions. CONCLUSION: PCT PLTs provided correction of prolonged bleeding times and transfusion intervals not significantly different than reference PLTs despite significantly lower PLT count increments and CCIs.     

Comparison of plateletpheresis with a standard and an improved collection device

A blood cell separator with a specialized separation chamber ([TNX-6]CS- 3000 Plus) was developed for the collection of platelet concentrates with higher platelet yields and lower white cell contamination than obtained with the standard blood cell separator (CS-3000). To compare these devices, normal donors were scheduled for paired plateletpheresis procedures spaced 4 weeks apart, with one procedure using the CS-3000 Plus and the other using the CS-3000. Overall, the platelet yield per unit (mean +/− SEM) was 4.3 +/− 0.1 × 10(11) with the CS-3000 Plus versus 3.7 +/− 0.1 × 10(11) with the CS-3000 (p < 0.001), and the white cell contamination per unit (mean +/− SEM) with the former was 2.4 +/− 0.7 × 10(6) versus 84.1 +/− 21.1 × 10(6) with the latter (p < 0.001). The sequence of procedures (i.e., the order in which the devices were paired) was selected randomly, and similar results were found regardless of sequence. When donors with predonation platelet counts of > or = 200 × 10(9) per L (n = 21) were studied separately, 76 percent of the collections by the CS-3000 Plus contained > or = 4 × 10(11) platelets versus 34 percent of those by the CS-3000 (p < 0.01), and 93 percent of the collections by the former contained < 5 × 10(6) white cells (69% contained < 1 × 10(6)) versus 0 percent of those by the latter (p < 0.01). Thus, platelet collections with the TNX-6 chamber consistently demonstrated high platelet yields and strikingly low white cell contamination–qualities that justify converting standard devices to devices with a TNX-6 chamber.     

Effect of storage time on clinical efficacy of single-donor platelet units

Decrements in platelet function and recovery are known to accumulate during the 5-day storage period, and the clinical response to platelets transfused after several days' storage has been suggested by some researchers to be less than that seen with platelets stored for shorter periods. The clinical response to single-donor platelet (SDP) units (as measured by corrected count increments [CCIs] and intertransfusion intervals) was investigated in autologous bone marrow transplant patients. Twenty-seven consecutive autologous bone marrow transplant patients with a variety of hematologic and solid organ malignancies were evaluated for posttransfusion CCIs after 419 SDP transfusions of units stored for 1 to 5 days. Patients were not excluded from the study because of clinical condition, such as fever or sepsis. The mean 15- minute posttransfusion CCI for SDP units stored for only 1 day (11,006 +/− 5,157) was no different than that for units stored for 5 days (10,225 +/− 4,481; p > 0.05); 24-hour posttransfusion CCIs were also not different if the SDP unit had been stored for 1 day or 5 days (6229 +/− 4489 vs. 4786 +/− 2759; p > 0.05) or for any intermediate period. Nor were intertransfusion intervals affected by storage time. While platelets may exhibit a progressive lesion during the 5-day storage period, these changes do not result in a decreased clinical response.     

Recovery, lifespan, and function of CPD-Adenine (CPDA-1) platelet concentrates stored for up to 72 hours at 4 C

We studied the in vivo recovery, lifespan, and hemostatic effectiveness of CPDA-1 platelet concentrates stored for up to 72 hours at 4 C. A total of 120 CPDA-1 concentrates containing an average (+/− 1 S.D.) of 6.6 +/− 2.0 × 10(10) platelets were prepared. The pH of the units following storage at 4 C was 6.8 +/− 0.2; no unit had a pH below 6.3. Autologous transfusion of six normal volunteers showed that platelets stored at 4 C for 72 hours had an in vivo recovery of 40 +/− 18 per cent and a lifespan of 5.1 +/− 1.5 days. The hemostatic effectiveness of CPDA-1 platelets was determined by platelet counts and template bleeding time measurements in 10 thrombocytopenic patients. Patients receiving 48-hour-stored platelets had a four- to six-hour posttranfusion corrected platelet increment averaging 15,300 +/− 3,200/microliter which was 67 +/− 34 per cent of expected recovery. Four of the five patients transfused with this preparation showed an improved bleeding time. In contrast, three patients receiving 72-hour- stored platelets had a four- to six-hour posttransfusion increment of 5,800 +/− 2,400/microliter that was only 26 +/− 13 per cent of the expected recovery; furthermore, only one of these patients showed any correction of the bleeding time. These data indicate that CPDA-1 platelets are hemostatically effective when stored at 4 C for up to 48 hours.     

A statistical model for estimating donor postdonation platelet counts after plateletpheresis

BACKGROUND: To avoid the need, in serial apheresis donors, either to delay plateletpheresis until a predonation platelet count is completed or to obtain a postdonation count after each procedure, a statistical model has been developed to predict the postdonation platelet count from the donor predonation platelet count, weight, and hematocrit. STUDY DESIGN AND METHODS: Predonation and postdonation platelet counts were measured in two groups of approximately 100 consecutive donors (Group A to test the model and Group B to validate it), and the postdonation counts were calculated with the model. Using stepwise multiple linear regression from donor data, estimated postdonation platelet counts were found to be comparable to the postdonation platelet counts actually measured. RESULTS: Estimated postdonation platelet counts × 10(9) per L (mean +/− SD) for each group, respectively, were Group A, 195 +/− 35, versus actual platelet counts of 195 +/− 39 (p = 0.43), and Group B, 183 +/− 36, versus actual platelet counts of 189 +/− 34 (p = 0.14). Sensitivity and specificity, respectively, were Group A, 57 and 99 percent and Group B, 62 and 99 percent. CONCLUSION: For most serial apheresis donors, application of this predictor model should preclude the need to obtain an extra postdonation platelet count.     

Longitudinal management with crossmatch‐compatible platelets for refractory patients: alloimmunization,response to transfusion,and clinical outcomes (CME)

BACKGROUND: The use of crossmatch‐compatible platelets (PLTs) improves posttransfusion corrected count increments (CCIs) in patients with alloimmune PLT refractoriness. However, few reports address the efficacy of utilizing this strategy for patients requiring intensive PLT transfusion therapy lasting several weeks to months. STUDY DESIGN AND METHODS: Medical records of patients with two or more PLT crossmatch assays performed between 2002 and 2010 were reviewed. All patients were refractory to random single‐donor apheresis PLT units, defined as two consecutive 1‐hour posttransfusion CCIs of less than 7500. A commercial solid‐phase adherence assay was used for crossmatching. RESULTS: Seventy‐one patients were included. A median of four crossmatch assays were performed per patient (range, 2‐17). Mean percent reactivity in initial (58.6%) versus last (55.3%) crossmatch assay for each patient demonstrated no trend toward progressive alloimmunization (p = NS). A total of 738 crossmatched PLT units were administered with a mean ± standard deviation CCI of 7000 ± 7900 (n = 443 units with adequate 1‐hr posttransfusion counts), a significant improvement over random PLTs (p < 0.001). Patients with an initial crossmatch reactivity of greater than 66% were significantly more likely to demonstrate at least one panreactive crossmatch assay, impacting the availability of compatible PLTs for optimum transfusion support. One patient (1.4%) developed WHO Grade IV bleeding. CONCLUSIONS: Progressive alloimmunization to mismatched antigens does not impact medium‐term transfusion support with crossmatched PLTs. Increased reactivity in the initial crossmatch assay can serve as a trigger to initiate workup for HLA‐matched PLTs as a second‐line approach. However, for most patients, medium‐term transfusion support with crossmatched PLTs offers an effective and rapid first‐line approach to management of PLT transfusion refractoriness.     

Pretransfusion incubation of apheresis platelets at 37 degrees C improves posttransfusion recovery

The effect of brief 37 degrees C pretransfusion incubation of apheresis platelets (n = 25) was studied in 14 allogenic bone marrow transplant recipients (5 children, 9 adults). Apheresis platelets were collected on a cell separator, divided in two aliquots, and stored 1 to 5 days at 22 degrees C during agitation. One aliquot was incubated at 37 degrees C for 1 hour before transfusion, and the other was transfused as a paired control. When the patient's peripheral platelet count fell below 30 x 10(9) per L, one aliquot was transfused. The other aliquot was transfused the following day. Each patient received the two aliquots in random order. Corrected count increment (CCI) at 1 hour after transfusion of 37 degrees C incubated platelets was 12.2 +/- 9.5 (mean +/- SD) compared to 7.5 +/- 5.4 for paired control platelets (p < 0.05). CCIs the next day were 4.4 +/- 6.1 and 2.4 +/- 2.7, respectively (not significant). It can be concluded that 37 degrees C incubation of apheresis platelets improves posttransfusion CCI.     

Large-volume leukapheresis for collection of mononuclear cells for hematopoietic rescue in Hodgkin's disease

BACKGROUND: Peripheral blood mononuclear cells (MNCs) collected by leukapheresis contain hematopoietic stem and progenitor cells that provide autologous hematopoietic rescue after high-dose chemotherapy, an approach that offers a significant benefit to patients with recurrent Hodgkin's disease. However, patients with low MNC counts may require 10 or more standard leukapheresis procedures for the collection of sufficient cells for hematopoietic rescue. STUDY DESIGN AND METHODS: The effectiveness of steady-state large-volume leukapheresis (LVL; 15- 35 L blood processed) was evaluated as a method for collecting MNCs for hematopoietic rescue in seven patients with recurrent Hodgkin's disease. LVL was performed on 2 consecutive days per week to collect 7 × 10(8) MNCs per kg. The circulating MNC counts on the first day of LVL and the total numbers of LVL, of MNCs collected, and of liters of blood processed were determined per patient. After high-dose chemotherapy and MNC transfusion, days to granulocyte and platelet engraftment were recorded. RESULTS: On the first day of LVL, patients had median circulating MNCs of 1536 (range, 504–3950) × 10(6) per L. The median number of LVL procedures per patient was four (range, 1.25-6), and the median L per kg of blood processed was 1.57 (range, 0.38-4.03). Simple regression analysis plotting L per kg against initial MNCs gave a curve with the equation y = e(1.42-(6.31 × 10E-4)x) (correlation coefficient = -0.97, R2 = 0.95, exponential fit). Without posttransfusion growth- factor support, median days to granulocyte engraftment were 19 (range, 12–26) and those to platelet transfusion independence were 34.5 (range, 10–57). CONCLUSION: LVL provides a useful method of collecting MNCs for hematopoietic rescue in patients with Hodgkin's disease. The patient's baseline MNC count provides a useful estimate of the volume required for LVL.     

Preparation and storage of platelet concentrates

A technique of platelet concentrate preparation and storage is presented which permits the maximum number of viable and functional platelets to be preserved for periods of 72 hours. Although the storage conditions must be followed precisely, the method is nevertheless simple to perform and does not require specialized expensive equipment. Critical factors include: 1) preparation of the platelet concentrates with an initial centrifugation of 1000 × g for 9 minutes and a second centrifugation of 3000 × g for 20 minutes (86%+/− 1 platelet yield), 2) a storage bag composed of either Fenwal's PL-146 or McGaw plastic, 3) constant gentle mixing, 4) a 70 ml residual plasma volume, and 5) room temperature storage (22 C +/− 2). In Vivo platelet recovery after 72 hours of storage at room temperature averaged 46 per cent +/− 3 and survival was 7.9 days +/− 0.3 (81% of fresh platelet viability). The function of these platelets as measured by the correlation between bleeding time and platelet count after transfusion of pooled platelets into unimmunized, aplastic thrombocytopenic recipients was as good as that of fresh platelets. Both viability and function of concentrated platelets stored at 4 C are severely compromised.     

Comparison of COBE white cell-reduction and standard plateletpheresis protocols in the same donors

BACKGROUND: It is necessary to protect patients from white cell (WBC)- caused side effects of platelet transfusion by reducing the WBC contamination in single-donor platelets. STUDY DESIGN AND METHODS: A new COBE Spectra WBC (leuko)-reduction system (LRS) was compared to the COBE standard plateletpheresis (standard) procedure. Each of 62 donors underwent plateletpheresis under the two protocols (LRS and standard). The collection efficiency and WBC contamination in the components collected using the techniques were compared. Platelets were counted in a cell counter and WBCs were counted using two full grids of a Nageotte chamber. RESULTS: The preseparation and postseparation numbers for red cells, WBCs, and platelets as well as the number of collected platelets were not different in the two techniques. Collection efficiency in the LRS procedures was 96.2 +/− 13.0 percent of that in the standard procedures. Median WBC contamination in the platelet components was 10,160 per LRS procedure and 56,500 per standard procedure. The purity of the LRS components was significantly improved (p = 0.001), as seen in a comparison of the WBC numbers in components per procedure after log10 transformation (LRS: 0.096 +/− 0.195 × 10(6); standard: 0.390 +/− 1.075 × 10(6)). CONCLUSION: These data suggest that the LRS procedure produces platelet concentrates with a collection efficiency that is comparable to that obtained with the standard technique and with a residual WBC content that satisfies even the most stringent criteria for filtered platelets. As this purity can be achieved without platelet loss or alteration, conventional fiber filtration no longer seems necessary or useful in this type of single-donor platelet component.     

Platelet transfusions administered to patients with splenomegaly

It is generally felt that increments in platelet counts following platelet transfusions to patients with splenomegaly are severely reduced as a result of splenic sequestration. The results of 631 random-donor platelet transfusions administered to 66 thrombocytopenic patients with palpable splenomegaly were analyzed. Increasing splenomegaly had a significant effect on corrected count increments (CCIs), with the greatest deterioration occurring in patients whose spleens were palpable greater than 2.0 cm below the left costal margin. A similar trend was noted when the percentage of transfusions with satisfactory CCIs was compared, although it should be noted that 42 percent of the transfusions produced CCIs greater than 7500, and a large proportion produced clinically helpful absolute increments. Splenomegaly also had an effect on platelet survival: in patients with CCIs greater than 7500, the mean ratio of 24-hour CCIs to 1-hour CCIs was 0.29 to 0.47 in patients with various degrees of splenomegaly, as compared to an expected value of 0.6 to 0.7. Sixteen patients, most with spleens palpable less than 5.0 cm below the left costal margin, consistently had CCIs greater than 7500. A significant fraction of patients with splenomegaly can benefit from platelet transfusion, and thus splenomegaly should not preclude intensive therapeutic approaches.     

Cryopreservation of hematopoietic progenitor cells with 5-percent dimethyl sulfoxide at −80 degrees C without rate-controlled freezing

BACKGROUND: Cryopreservation of hematopoietic cells with the rate- controlled method is used in the majority of centers. In recent years, there has been a trend toward the simplification of the process. STUDY DESIGN AND METHODS: A simplified method for cryopreservation was developed with 5-percent dimethyl sulfoxide (DMSO) as the sole cryoprotectant without rate-controlled freezing. Experiments were done with progressive concentrations of DMSO, ranging from 0 to 10 percent. With DMSO concentrations from 5- to 10-percent, the best recovery and viability for hematopoietic progenitor cells were observed. Hematopoietic progenitor cells with plasma and 5-percent DMSO were frozen and stored in a -80 degrees C mechanical freezer. Ten patients with solid and hematologic malignancies underwent transplantation with autologous hematopoietic progenitor cells. RESULTS: The median number of transfused mononuclear cells and CD34+ cells was 3.70 (3.1-8.2) × 10(8) per kg and 1.70 (0.8-6.5) × 10(6) per kg, respectively. The median number of transfused colony-forming units-granulocyte-macrophage was 12.45 (3.4-55.3) × 10(4) per kg. All patients showed rapid and sustained engraftment. The mean times to reach a neutrophil count of 0.5 × 10(9) per L and a platelet count of 50 × 10(9) per L were 11.50 +/− 1.70 and 13.90 +/− 3.98 days, respectively. All patients are alive and without transfusion requirements in complete remission 2 to 8 months after transplantation. CONCLUSION: This simplified cryopreservation technique will be useful for institutions without rate- controlled freezing facilities. Moreover, this method diminishes the amount of DMSO infused to patients, as well as its toxicity.     

Frequency and functional relevance of genetic threonine145/methionine145 dimorphism in platelet glycoprotein Ib alpha in an Italian population

BACKGROUND: Threonine145/methionine145 dimorphism in platelet glycoprotein (GP) Ib alpha defines the human platelet antigen (HPA)-2 system that has been implicated in refractoriness to HLA-matched platelet transfusion and in neonatal immune thrombocytopenic purpura. STUDY DESIGN AND METHODS: The occurrence of this amino acid dimorphism was investigated in 379 Italian blood donors by studying their genomic DNA. Two oligonucleotide primers, Ib alpha-3 (5'-GGACGTCTCCTTCAACCGGC- 3') and Ib alpha-4 (5'-GCTTTGGTGGGGAACTTGAC-3'), were used in a polymerase chain reaction to generate a 591-base pair fragment that was digested with the restriction enzyme Acy I. To investigate whether this dimorphism is involved in the binding of von Willebrand factor (vWF) to GPlb, the binding of vWF to the GPlb/IX complex was measured in two Met145/Met145 and two Thr145/Thr145 subjects. RESULTS: The genotypic frequencies are 78.9% for Thr/Thr, 19.8% for Thr/Met), and 1.3% for Met/Met; the allelic frequencies are 88.8% for Thr145 and 11.2% for Met145. Estimates for binding of subunit molecules per platelet at saturation and inhibition constant in mol per L, respectively, follow. In the presence of ristocetin (0.5 mg/mL), they are 11,460 +/− 2,040 and 1.26 +/− 0.44 × 10(-8) for normals and 11,230 +/− 2,330 and 1.29 +/− 0.48 × 10(-8) for patients. In the presence of botrocetin (2.5 micrograms/mL), they are 64,260 +/− 7,760 and 2.99 +/− 0.96 × 10(-8) for normals and 65,770 +/− 11,570 and 2.47 +/− 0.22 × 10(-8) for patients. Platelet aggregation responses obtained using platelet-rich plasma from donors with Met145/Met145 or Thr145/Thr145 genotype were within normal limits. CONCLUSION: Genotypic and phenotypic frequencies in the HPA-2 system in this population are consistent with those reported among the white population. Furthermore, the HPA-2 system is not involved in the binding of vWF to GPlb.     

Evaluation of platelet concentrates prepared from buffy coats and stored in a glucose-free crystalloid medium

Comparison was made between platelet concentrates prepared from pools of buffy coats removed from standard blood donations and stored in a glucose-free, commercially available crystalloid solution (BC-PCs) and standard platelet concentrates prepared from platelet-rich plasma (PRP-PCs). Platelet yield in BC-PCs and PRP-PCs was 59 and 75 percent of donated platelets, respectively. The number of total white cells in 1 BC-PC unit, prepared from a pool of 7 buffy coats, was 21 x 10(6), i.e., 50 times lower than that of 7 units of PRP-PCs. The in vitro values of adequate platelet quality were maintained for 10 days in BC-PCs stored in 1000-mL polyolefin bags. Prolonged bleeding times were reduced or corrected in three of three thrombocytopenic leukemic patients evaluated before and after transfusion of stored BC-PCs. Pretransfusion and 1- and 24-hour posttransfusion median platelet counts in 57 leukemic recipients during 4 months of routine transfusion of BC-PCs (n = 93) were 14, 35, and 27 x 10(9) per L, while those of PRP-PCs (n = 246) were 13, 37, and 31 x 10(9) per L, respectively. No reactions to BC-PCs were reported, but a 1.3 percent rate of reaction to PRP-PC transfusions was reported. This study indicates that BC-PCs are a good alternative to PRP-PCs for platelet support of thrombocytopenic patients.     

Simultaneous collection of platelets and cryoprecipitate by plasma- exchange donation

To increase cost efficiency, the simultaneous collection of platelets during plasma-exchange donation of cryoprecipitate was investigated. Sixteen desmopressin (DDAVP)-stimulated donors underwent 90 simultaneous donations. Permanent donor plasma loss for each donation averaged 150 ml in cryoprecipitate and 151 ml in platelet concentrates. Mean factor VIII (FVIII) yield was 4699 +/- 2754 IU per donation. The mean yield in the platelet products was 4.63 X 10(11) platelets; aggregation properties and posttransfusion increments were satisfactory. White cell contamination averaged 4.05 X 10(9) but could be lowered by a secondary centrifugation. The direct cost for a single-donor platelet transfusion produced in this way is estimated at $102.19 and that for FVIII at $0.055 per IU. Simultaneous donation is technically feasible and safe for donors, and it provides functional products that are more cost-effective than apheresis platelets or cryoprecipitate donated separately.     

Transfusion of ABO-nonidentical platelets is not associated with adverse clinical outcomes in cardiovascular surgery patients

BACKGROUND: Current blood transfusion standards in Canada and the United States permit transfusion of ABO-nonidentical platelets when ABO-identical platelets are not available. This practice increases the availability of platelets, a component in chronic shortage in Ontario, Canada because of the 5-day shelf-life. The impact of transfusing ABO-nonidentical platelets on patient outcomes is unknown. STUDY DESIGN AND METHODS. A retrospective review of 1721 patients who had cardiovascular surgery between November 1989 and December 1999 and who had also received a platelet transfusion perioperatively was conducted. The impact of platelet and plasma incompatibility on clinical outcomes was analyzed. RESULTS: The analysis included 1691 patients who were divided into two groups according to the compatibility of the first platelet transfusion received: ABO-identical platelet transfusion (n = 1008) and ABO-nonidentical platelet transfusion (n = 683). The only difference in baseline characteristics between the two groups was that there were more urgent cases in the ABO-identical platelet transfusion group (p = 0.04). There were no significant differences in mortality at 30 days (10% for both groups, p = NS) or in postoperative length of stay (median, 7.0 days for both groups, p = NS). No significant differences were found with respect to the use of blood components, indices of bleeding, incidence of infection, or platelet CCIs. CONCLUSION: Transfusion of ABO-nonidentical platelets in patients undergoing cardiovascular surgery is not associated with an adverse impact on patient outcome.     

Reactions and platelet increments after transfusion of platelet concentrates in plasma or an additive solution: a prospective, randomized study

BACKGROUND: Reactions after platelet transfusions are rather common and frequently are caused by plasma constituents. In recent developments, the preparation and storage of platelet concentrates (PCs) in a platelet additive solution (PAS-2) have been shown to result in acceptable storage conditions. A major drawback of the use of these PCs is the progressive increase of P-selectin-positive platelets during storage. The clinical benefit of transfusions of PCs in PAS-2 was studied. STUDY DESIGN AND METHODS: PCs prepared from buffy coats were suspended in either plasma or PAS-2 and stored for up to 5 days. Clinical responses were evaluated in a prospective study in 21 patients treated with intensive chemotherapy for hematologic malignancies. Eligible patients were randomly assigned to receive prophylactic transfusions of PCs prepared in either plasma or PAS-2. Reactions and CCIs were recorded after each transfusion. RESULTS: The incidence of reactions in 12 patients given PCs in plasma (n = 192) was 12 percent. Transfusions to 9 patients of PCs in PAS-2 (n = 132) showed a reduction in the incidence of reactions to 5.3 percent (p<0.05). The average 1-hour and 20-hour CCIs after transfusion of PCs in plasma were 20.7 +/- 8. 5 and 11.5 +/- 8.0, respectively. CCIs after transfusion of PCs in PAS-2 were significantly lower: the average 1-hour CCI was 17.1 +/- 6.6 (p<0.001) and the average 20-hour CCI was 9.5 +/- 7.0 (p<0.05). Storage conditions of PCs were optimal: in each group, average 1-hour CCIs of both fresh and stored PCs were similar. The 20-hour CCIs after the transfusion of fresh and stored PCs in PAS-2 also were similar. CONCLUSION: Transfusion of PCs in PAS-2 significantly reduces the incidence of reactions. The 1-hour and 20-hour CCIs after transfusion of PCs in PAS-2 were significantly lower than the CCIs after transfusion of PCs in plasma. Because storage conditions of both PCs were found to be optimal, the decrease in CCIs after transfusion of PCs prepared in PAS-2 may be caused by rapid elimination of a subpopulation of P-selectin-positive platelets from the circulation.     

Engraftment with peripheral blood stem cells collected by large-volume leukapheresis for patients with lymphoma

Seven patients with refractory lymphomas underwent marrow reconstitution with peripheral blood stem cells (PBSCs) harvested by large-volume leukapheresis (LVL). PBSCs were collected from all patients more than 1 month after the last cycle of chemotherapy, and no patient received growth factors. The median number of LVL procedures performed per patient was 4.5, with a mean volume of 24.5 L of blood processed per procedure to obtain 7 x 10(8) mononuclear cells per kg. Autologous PBSCs and platelets were frozen at a controlled rate in plasma and 10-percent dimethyl sulfoxide and stored in the vapor phase of liquid nitrogen. This group of patients was compared to a control group (n = 18) who received medullary marrow (MM) transplants for the same diagnoses under the same protocols during the same period. Posttransplant days to white cell engraftment (PBSC = 17, MM = 15.5) were no different. Days to platelet independence were significantly longer in the LVL PBSC group (PBSC = 33, MM = 16; p < 0.05). This pattern of engraftment is typical of patients treated in this manner. Although Day 0 platelet counts (PBSC = 75.5 x 10(9)/L, MM = 85 x 10(9)/L) and total single-donor unit platelet use (PBSC = 8, MM = 9) were no different, Day 1 platelet counts (PBSC = 128 x 10(9)/L, MM = 61.5 x 10(9)/L; p < 0.05) and Day 14 platelet use (PBSC = 5, MM = 8; p < 0.05) were significantly different, because of the transfusion of cryopreserved autologous platelets with PBSCs on Day 0.     

Effectiveness of Platelet Transfusion in Leukemia and Aplastic Anemia

Hemorrhage resulting from thrombocytopenia in patients with acute leukemia and aplastic anemia can be controlled by platelet transfusions. Severe gross hemorrhage was rarely observed when platelet counts were higher than 20,000 per cu. mm. Transfusion of 1 × 10¹¹ platelets produced an average increment of 12–14,000 platelets per cu. mm./square meter (m²) of body surface in acute leukemia. One unit of platelet rich plasma (PRP) contains an average of 1 × 10¹¹ platelets and 4 PRP/m² twice weekly will maintain the platelets above 20,000 per cu. mm. most of the time. When very large doses of platelets are required in a small volume then platelet concentrates (PC), prepared by centrifuging PRP and removing most of the plasma, are used. PC are 80 to 90 per cent as effective as PRP in elevating the platelet count if prepared from plasma with a p H of 6.8 or less, achieved by the addition of citric acid.
The major hazard of platelet transfusion is posttransfusion hepatitis. This can be minimized by the use of plasmapheresis thus using the same donors repeatedly. In the presence of anemia platelets can be given effectively in fresh whole blood transfusions until the patient's hematocrit is raised.