1-Deamino-8-D-arginine vasopressin (DDAVP) increases platelet membrane expression of glycoprotein Ib in patients with disorders of platelet function and after cardiopulmonary bypass

Effect of DDAVP on Platelet Activation and Platelet-Derived Microparticle Generation

BACKGROUND

 The way by which 1-deamino-8-D-arginine vasopressin (DDAVP) acts on platelets remains unclear. Data from the literature tend to show that there is no definite effect on platelet activation, but recent work has suggested that a subtype of platelets, activated by the combined action of collagen and thrombin, was triggered by DDAVP. Moreover, platelet microparticles (PMPs), which have been shown to be procoagulant, have rarely been studied in this context. The goal of this study was to analyze the effects of DDAVP on PMPs' release through platelet activation.

METHODS

 Fifteen out of 18 consecutive patients undergoing a therapeutic test with DDAVP were included. They were suffering from factor VIII deficiency or from von Willebrand disease. The expression of P-selectin and PAC-1 binding on platelets and the numbers of circulating PMPs were evaluated ex vivo before and after DDAVP infusion. Peripheral blood was collected on CTAD to limit artifactual platelet activation.

RESULTS

 DDAVP induced a significant decrease of platelet counts and volume. Only small changes of P-selectin expression and PAC-1 binding were observed. Considering PMPs, two populations of patients could be defined, respectively, with (120%, n = 6) or without (21%, n = 7) an increase of PMPs after DDAVP. The decrease in platelet counts and volume remained significant in the group of responders.

CONCLUSION

 This study shows that DDAVP induces the generation/release of PMPs in some patients with factor VIII deficiency and von Willebrand disease 1 hour after DDAVP infusion.

The effectiveness of low-dose desmopressin in improving hypothermia-induced impairment of primary haemostasis under influence of aspirin - a randomized controlled trial

BACKGROUND

Mild hypothermia (34-35 °C) increases perioperative blood loss. Our previous studies showed that desmopressin could have in vitro beneficial effects on hypothermia-induced primary haemostasis impairment. In this study, we investigate the in vitro effects of desmopressin on hypothermia-induced primary haemostasis impairment under the influence of aspirin in healthy volunteers.

METHODS

Sixty healthy volunteers were randomly allocated to taking aspirin 100 mg or placebo for three days. On the sixth day blood samples were taken before and after the injection of desmopressin (1.5 microgram or 5 microgram) or normal saline subcutaneously. Measurements including Platelet Function Analyzer (PFA-100®) closure times, plasma von Willebrand Factor antigen, haemoglobin and platelet levels were made at 32 °C and 37 °C respectively.

RESULTS

Collagen/epinephrine closure time (EPICT) was significantly prolonged by 21.13 % (95 %CI 2.34-39.74 %, p = 0.021) in aspirin group at 37 °C. While hypothermia alone prolonged both collagen/adenosine diphosphate (ADPCT) and EPICT by 17.63 % (95 %CI 13.5-20.85 %, p < 0.001) and 8.0 % (95 %CI 6.38-10.04 %, p = 0.024) respectively, addition of aspirin only further prolonged EPICT by 19.9 % (95 %CI 3.32-36.49 %, p = 0.013). In aspirin group, desmopressin 1.5 microgram and 5 microgram significantly reduced ADPCT to below baseline levels at 37 °C (p = 0.025 and <0.001 respectively), whereas reduction in EPICT was seen with desmopressin 5 microgram (p =0.008). The effect was less pronounced at 32 °C, with a significant reduction in EPICT obtained with a dosage of 5 microgram only (p = 0.011).

CONCLUSION

It was shown that aspirin could further potentiate the hypothermia-induced closure time prolongations. Low dose desmopressin (1.5 microgram) reduced PFA-100® closure times towards baseline. A higher dosage (5 microgram) further reduced the closure times below baseline. Therefore low dose desmopressin (1.5 microgram) might have the potential to correct hypothermia-induced primary haemostasis impairment under the influence of aspirin during the perioperative period.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01382134.

The use of DDAVP in children with bleeding disorders

Desmopressin (1-deamino-8-D-arginine vasopressin, DDAVP) has been used in children with von Willebrand disease (VWD) and Hemophilia A for almost 35 years. This treatment has substantially lowered the number of children exposed to human plasma derived products, with a good safety profile, and at very low cost. The response to DDAVP has been shown to be associated with age, baseline factor level, and genetic mutations. A DDAVP challenge test is recommended. DDAVP has also been used to prevent and treat bleeding episodes in children with platelet function defects and other disorders associated with bleeding tendency.

Effects of desmopressin on platelet function under conditions of hypothermia and acidosis: an in vitro study using multiple electrode aggregometry*

SUMMARY

Hypothermia and acidosis lead to an impairment of coagulation. It has been demonstrated that desmopressin improves platelet function under hypothermia. We tested platelet function ex vivo during hypothermia and acidosis. Blood samples were taken from 12 healthy subjects and assigned as follows: normal pH, pH 7.2, and pH 7.0, each with and without incubation with desmopressin. Platelet aggregation was assessed by multiple electrode aggregometry. Baseline was normal pH and 36 degrees C. The other samples were incubated for 30 min and measured at 32 degrees C. Acidosis significantly impaired aggregation. Desmopressin significantly increased aggregability during hypothermia and acidosis regardless of pH, but did not return it to normal values at low pH. During acidosis and hypothermia, acidosis should be corrected first; desmopressin can then be administered to improve platelet function as a bridge until normothermia can be achieved.

Hämostyptika

Desmopressin (DDAVP) wurde 1966 als Abkömmling des antidiuretischen Hypophysenhormons Arginin-Vasopressin synthetisch hergestellt. Zu den antidiuretischen Indikationen zählen Diabetes insipidus und Enuresis nocturna, zudem wird es in Tests zur Bestimmung der Nierenkonzentrationsfähigkeit verwendet

A point-of-care assessment of the effects of desmopressin on impaired platelet function using multiple electrode whole-blood aggregometry in patients after cardiac surgery

BACKGROUND

Blood loss after cardiac surgery can be caused by acquired platelet dysfunction after cardiopulmonary bypass. Monitoring of platelet function is clinically important for the identification of patients experiencing such platelet dysfunction. 1-Deamino-8-D-arginine vasopressin (desmopressin acetate, DDAVP) has been shown to augment platelet function and to reduce blood loss in patients with platelet dysfunction. In this study, we examined the feasibility of whole blood multiple electrode aggregometry (MEA) for the detection of cardiopulmonary bypass-induced platelet dysfunction and investigated its ability to monitor DDAVP treatment.

METHODS

Fifty-eight consecutive patients with blood loss exceeding 150 mL/h in the first 2 consecutive hours after cardiac surgery were screened for suspected isolated platelet dysfunction. Twenty-two patients had suspected isolated platelet dysfunction and were enrolled in the study. Platelet dysfunction was assumed if conventional coagulation analyses (platelet count, activated partial thromboplastin time, international normalized ratio, and fibrinogen) did not show abnormal values as defined for transfusion of allogenic blood products, and no surgical cause of bleeding was suspected. Eleven patients received 0.3 microg/kg DDAVP, and 11 patients received no therapy in a nonrandomized manner. MEA was performed after stimulation with thrombin receptor-activating peptide (TRAPtest, 32 microM), adenosine diphosphate (ADPtest, 6.4 microM), and arachidonic acid (ASPItest, 0.5 mM) before and 2 hours after intervention. Conventional laboratory variables were recorded. The Mann-Whitney test was used to detect differences between the groups, and the Wilcoxon test was used to detect differences before and after intervention.

RESULTS

All enrolled patients showed platelet dysfunction that manifested as impaired platelet aggregation in MEA before intervention. After the intervention, platelet function improved in the DDAVP group (49 U [30/72 U], median [25th/75th percentile] postintervention vs 15 U [8/21 U] preintervention for the ASPItest [P < 0.001]; 35 U [24/54 U] vs 14 U [7/28 U] for the ADPtest [P = 0.002]; and 85 U [66/115 U] vs 64 U [26/88 U] for the TRAPtest [P = 0.007]). In contrast, MEA remained unchanged in the control group (22 U [10/50 U] postintervention vs 33 U [14/57 U] preintervention for the ASPItest [P = 0.175]; 17 U [12/20 U] vs 14 U [10/28 U] for the ADPtest [P = 0.147]; and 65 U [41/89 U] vs 57 U [30/91 U] for the TRAPtest [P = 0.123]).

CONCLUSIONS

Impaired platelet function after cardiac surgery can be assessed at the bedside using MEA. The effect of DDAVP on impaired platelet function can also be detected as significant improvement in platelet aggregation to all activators. This device might be helpful for the identification of patients who may benefit from DDAVP therapy.

A practical concept for preoperative management of patients with impaired primary hemostasis

In a prospective study, 254 of 5649 unselected patients scheduled for surgery at our hospital were identified preoperatively as having either acquired (n=182) or inherited (n=72) impaired primary hemostasis (platelet dysfunction including von Willebrand disease). All patients were initially pretreated with desmopressin (DDAVP). Response to DDAVP or subsequent treatment(s) was defined as correction of any one of the abnormal PFA-100 platelet function tests. The non-responders were additionally treated with tranexamic acid or aprotinin; those with von Willebrand disease (vWD) received factor VIII concentrates with von Willebrand factor (vWF). Those still unresponsive to therapy received conjugated estrogens and, as a last attempt, a platelet transfusion. The administration of DDAVP led to a correction of platelet dysfunction in 229 of the 254 patients treated (90.2%). Tranexamic acid was effective in 12 of 16, aprotinin in 3 of 5, and factor VIII concentrates with vWF in all 4 patients with unresponsive to DDAVP. The remaining 6 patients were pretreated with conjugated estrogens, and 2 of these patients were additionally treated with platelet transfusion. The frequency of blood transfusion was lower, but not statistically significant (9.4% vs. 12.2%: p = 0.202) in preoperatively treated patients with impaired hemostasis than in patients without impaired hemostasis. In a retrospective group, the frequency of blood transfusion was statistically significant higher (89.3% vs. 11.3%: p < 0.001) in patients without preoperative correction of impaired hemostasis than in patients without impaired hemostasis. Preoperative correction of impaired primary hemostasis is possible in nearly all patients affected, and results in a reduction of homologous blood transfusions.

DDAVP normalized the bleeding time in patients with congenital platelet TxA2 receptor abnormality

BACKGROUND

An Arg60-to-Leu mutation was found in the first cytoplasmic loop of the PLT TxA2 receptor as a new congenital PLT disorder characterized by impaired responsiveness to TxA2. However, it has not been clarified whether DDAVP is effective in correcting the bleeding time (BT) in this PLT disorder.

STUDY DESIGN AND METHODS

DDAVP (0.4 microg/kg) was intravenously administered over 20 minutes in five patients with this PLT disorder, and template BT, PLT retention to glass beads, PLT aggregation, and a coagulation study were performed before and after the infusion of DDAVP. PLT TxA2 synthesis defects (cyclo-oxygenase deficiency, volunteers taking aspirin), thrombasthenia, and Bernard-Soulier syndrome were also included in this study.

RESULTS

The normalization of BT was found in all patients with this PLT disorder, and one of the patients successfully underwent oral surgical procedures with DDAVP as the only hemostatic agent. DDAVP was also efficacious in the TxA2 synthesis defect but not in other disorders. FVIII coagulation activity, vWF antigen, and ristocetin cofactor significantly increased in all patients after DDAVP, but no changes were seen in the PLT retention rate and PLT aggregation study after DDAVP infusion.

CONCLUSION

DDAVP was effective in correcting BT in patients with impaired responsiveness to TxA2 as well as impaired production of TxA2.

Depression is associated with an increase in the expression of the platelet adhesion receptor glycoprotein Ib

There is a significant association between cardiovascular disease and depression. Previous studies have documented changes in platelets in depression. It is unknown if depression causes functional changes in platelet surface receptors. Therefore, we analyzed (1) the surface expression of glycoprotein (GP)Ib and the integrin receptor alpha(IIb)beta(IIIa), receptors involved in platelet adhesion and aggregation, (2) CD62 (P-selectin) and CD63, integral granule proteins translocated during platelet activation, (3) platelet aggregation in response to ADP and (4) plasma levels of glycocalicin and von Willebrand factor (vWF), in depressed patients compared to healthy volunteers. Fifteen depressed patients with a Hamilton depression score of at least 22 and fifteen control subjects were studied. Platelets were assessed for surface expression levels of GPIb, alpha(IIb)beta(IIIa), CD62 and CD63 by flow cytometry. Genomic DNA was isolated to investigate a recently described polymorphism in the 5' untranslated region of the GPIbalpha gene. The number of GPIb receptors was significantly increased on the surface of platelets from patients with depression compared to control subjects. Surface expression of CD62 was also significantly increased in the depressed patients versus control subjects. There was no significant difference between depressed patients and healthy volunteers in the surface expression of alpha(IIb)beta(IIIa) or CD63, or in glycocalicin or vWF plasma concentration, or ADP-induced aggregation. There was no difference in allele frequency of the Kozak region polymorphism of the GPIbalpha gene, which can affect GPIb expression. The results of this study demonstrate that the number of GPIb receptors on platelets are increased in depression and suggest a novel risk factor for thrombosis in patients with depression.

Use of point-of-care test in identification of patients who can benefit from desmopressin during cardiac surgery: a randomised controlled trial

BACKGROUND

Platelet dysfunction is a major cause of excessive microvascular bleeding after cardiac surgery. A new point-of-care test (hemoSTATUS) can identify patients at risk of excessive bleeding. We aimed to find out whether patients who can benefit from desmopressin during cardiac surgery can be identified by this test.

METHODS

We enrolled 203 patients scheduled for elective cardiac surgery in a prospective, double-blind, placebo-controlled trial. Patients with abnormal hemoSTATUS clot-ratio results (<60% of maximum in channel 5) after discontinuation of cardiopulmonary bypass were randomly assigned desmopressin (n=50) or placebo (n=51). Patients with normal clot ratios were included in an untreated control group (n=72).

FINDINGS

Intraoperative platelet counts and clot ratios were significantly higher in the untreated control group than in the study-drug groups. In intensive care, clot ratios in patients who received desmopressin were similar to those in the untreated control group, despite significantly lower platelet counts, but were lower in the placebo group than in the other two groups (p=0.0001). Compared with the placebo group, patients who received desmopressin had less blood loss in 24 h (mean 624 [SD 209] vs 1028 mL [682] p=0.0004) and required less transfusion of red blood cells (1.1 [022] vs 2.2 U [0.32] p=0.009), platelets (0.1 [0.04] vs 1.9 U [4.5] p=0.0001), and fresh-frozen plasma (0.1 [0.07] vs 0.75 U [0.21] p=0.0008), and had less total blood-donor exposures (1.56 [0.31] vs 5.2 [0.8] p=0.0001). Placebo patients also had substantially higher blood loss and transfusion requirements than untreated control patients.

INTERPRETATION

Patients identified with hemoSTATUS as being at increased risk of excessive bleeding after cardiac surgery can benefit from administration of desmopressin. Further studies are, however, needed to confirm these findings as well as to identify the mechanism of action and safety of desmopressin in the clinical setting.

Monitoring of hemostasis in cardiac surgical patients: impact of point-of-care testing on blood loss and transfusion outcomes

Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) are at increased risk for excessive perioperative blood loss requiring transfusion of blood products. Strategies to optimize administration of heparin and protamine and the assessment of their effects on coagulation are evolving in cardiac surgical patients. Two recent evaluations have focused on the use of multiple point-of-care (POC) coagulation assays for patient-specific adjustment of heparin and protamine dosage. These studies indicate that blood loss and transfusion requirements in cardiac surgical patients may be reduced with more accurate control of heparin anticoagulation and its reversal. Blood component administration in patients with excessive post-CPB bleeding is generally empiric in part, related to turnaround times of laboratory-based tests. Methods are now available for rapid, POC assessment of coagulation to allow appropriate, targeted therapy for acquired hemostatic abnormalities. Recent studies indicate that a rapid evaluation of thrombocytopenia and coagulation factor deficiencies with POC tests can facilitate the optimal administration of pharmacologic and transfusion-based therapy in patients who exhibit excessive bleeding after CPB. POC tests that assess platelet function have been developed, and their use may facilitate identification of which patients at risk for excessive blood loss may respond to pharmacologic interventions such as desmopressin acetate or antifibrinolytic agents.

Relationship between leukocyte count and patient risk for excessive blood loss after cardiac surgery

OBJECTIVE

To evaluate the relationship between leukocyte counts and risk for excessive blood loss after cardiac surgery when including numerous demographic, operative, and laboratory factors in the comparison.

DESIGN

A prospective, clinical evaluation.

SETTING

A point-of-care laboratory and the cardiac surgical unit of a university-affiliated tertiary center.

PATIENTS

Patient-related and hematologic variables were measured, using blood specimens obtained from 89 hospitalized patients who underwent cardiac surgery involving cardiopulmonary bypass.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographic, operative, and transfusion-related data were recorded for each patient. Routinely obtained measurements of laboratory-based prothrombin time, partial thromboplastin time, complete blood count, and bleeding time were recorded. Hemoglobin concentration, platelet count, and red and white blood cell counts were measured with an on-site instrument before initiation (pre-cardiopulmonary bypass) and before discontinuation (end-cardiopulmonary bypass) of cardiopulmonary bypass. Hematocrit was calculated using recorded variables, and white blood cell percent change values were calculated using white blood cell counts from both periods, using the following formula: [(end-cardiopulmonary bypass - pre-cardiopulmonary bypass)/pre-cardiopulmonary bypass] x 100. When we excluded four patients who had a surgical source of post-cardiopulmonary bypass bleeding, significant (p < .0001) relationships were observed between white blood cell count (r2 = .46) and white blood cell percent change values (r2 = .71) and cumulative mediastinal chest tube drainage in the first 4 postoperative hours in 85 patients. Bayes theorem was used to evaluate the predictive ability of hematologic measurements in identifying patients with excessive bleeding (n = 24), defined as >1000 mL of cumulative chest tube drainage in the first 24 postoperative hours, when compared with patients without excessive bleeding (n = 61). Demographic and operative variables were similar between these patients except that patients with excessive bleeding required more red blood cell, platelet, and plasma transfusions during the postoperative interval. Significantly (p < .0001) greater white blood cell percent change values were obtained in the excessive bleeding cohort (119 +/- 93 percent change) when compared with patients without excessive bleeding (28 +/- 36 percent change).

CONCLUSIONS

On-site measurements of white blood cell count, as an index of the inflammatory response to extracorporeal circulation, may be useful in identifying patients at increased risk for excessive bleeding. Further studies are needed to examine whether white blood cell counts during multiple cardiopulmonary bypass periods may identify patients with an exaggerated inflammatory response to extracorporeal circulation. By using this information, physicians may be able to intervene with anti-inflammatory medications and blood preservation techniques.

Strategies to reduce the need for peri-operative blood transfusion

Therapeutic regimens involving the transfusion of blood components are a matter of debate, not only with regard to patients' safety, but also with regard to cost-effectiveness. The following different measures to reduce the use of blood components and their efficacy are discussed: autologous transfusion, including predonation, isovolaemic haemodilution and peri-operative retransfusion; toleration of a lower haematocrit; and measures to reduce blood loss. In particular, a combination of these methods may be most effective at reducing transfusion needs.

Reduction in requirements for allogeneic blood products: pharmacologic methods

BACKGROUND

Numerous articles describe the reduction of perioperative bleeding by the therapeutic or prophylactic administration of drugs such as prostacyclin, desmopressin, and natural or synthetic antifibrinolytics.

METHODS

A review of the literature was carried out to help the reader define the indications of these drugs during cardiopulmonary bypass operations, highlight the questions that remain concerning their indications and modes of action, and suggest future studies to answer these remaining questions.

RESULTS

Prostacyclin reduces platelet trauma induced by extracorporeal circulation but does not effectively reduce postoperative bleeding and transfusion requirements. Desmopressin acts as a "glue," improving platelet adhesion, and may be effective when postoperative bleeding is excessive, but its routine use in cardiac operations cannot be recommended. Natural and synthetic antifibrinolytics inhibit plasmin and plasmin-induced platelet dysfunction. These agents have been shown to decrease bleeding and the need for allogeneic transfusions after open heart operations. However, with antifibrinolytic drugs, the risk of thromboembolic phenomena cannot be neglected. With aprotinin, this risk appears to be minimal when the drug is used at concentrations high enough to inhibit plasma kallikrein also.

CONCLUSIONS

Prophylactic antifibrinolytics are efficacious, but their routine use remains controversial, both for economic reasons and for fear of thromboembolic complications.

Treatment of excessive mediastinal bleeding after cardiopulmonary bypass

BACKGROUND

Excessive mediastinal bleeding after cardiopulmonary bypass is one of the most frequently reported complications of cardiac operations. Appropriate treatment requires a rapid and effective diagnostic work-up, based on the knowledge of the pathophysiology induced by cardiopulmonary bypass.

METHODS

Possible causes, diagnostic methods available, and therapeutic approaches are reviewed in the light of the literature published on excessive bleeding after cardiac operations.

RESULTS

When bleeding is massive (> 250 to 300 mL/h for the first 2 hours, > 150 mL/h thereafter), immediate surgical reexploration is mandatory. When bleeding is less important (50 to 150 mL/h), the decision to reoperate should be based on the presence of hemodynamic compromise or a suspected surgical cause. Otherwise, coagulation testing should allow the correction of hemostatic defects as appropriate with protamine, platelet concentrates, fresh frozen plasma, desmopressin, or antifibrinolytics. Hypothermia and hypotension should be corrected and a trial of positive end-expiratory pressure may be considered if diffuse mediastinal oozing (especially from the bed of the mammary artery) is suspected.

CONCLUSIONS

A protocol is suggested to guide treatment, taking into account the rapidity of blood loss and the suspected underlying cause.