The role of the pulmonary circulation in the regulation of coagulation and fibrinolysis in relation to major surgery

The Bone Cement Hypercoagulation Syndrome: Pathophysiology, Mortality, and Prevention

Since Charnley introduced acrylic cement to seal metallic hip prostheses in the 1950s, reports of perioperative fatal cardiorespiratory and vascular dysfunctions have been published. Studies on humans and animals have shown neurogenic stimulation and substantial local and systemic activation of coagulation are caused by surgical bone marrow damage and chemical cell destruction by toxic monomeric methyl methacrylate from the implanted cement and other tissue-released substances. Venous blood-borne cell fragments and conjugates of activated cells from the surgical site are sequestered and trapped in the pulmonary microcirculation. A substantial hypercoagulation occurs in the lung circulation. Hypercoagulable blood is passed over to the arterial side and may cause vessel obliteration and organ damage. This process may affect the brain, heart, and kidneys and, through the release of vasoactive substances, introduce hemodynamic imbalances that can lead to fatal outcomes in susceptible populations such as elderly patients with hip fractures. The main underlying pathophysiologic processes leading to these occasionally devastating outcomes are a substantial activation of coagulation and cell destruction caused by the toxic substance released by curing bone cement and several vasoactive substances.

Orthostatic Challenge-Induced Coagulation Activation in Young and Older Persons

The incidence of thrombosis increases with aging. We investigated the coagulatory/haemostatic system across the ages and tested the hypothesis that older persons have a hypercoagulable state compared to younger persons at rest, and that standing up (orthostasis) leads to greater changes in coagulation in older persons. In total, 22 older and 20 young participants performed a 6 min sit-to-stand test (orthostatic challenge). Blood was collected prior to and at the end of standing and haemostatic profiling was performed via thrombelastometry (TEM), calibrated automated thrombogram (CAT) and standard coagulation assays. At baseline, three CAT-derived values indicated enhanced capability to generate thrombin in older participants. However, other measured parameters did not suggest a hypercoagulable state in older participants: prolonged TEM-derived coagulation times (295 vs. 209 s, medians, p = 0.0025) and prothrombin times (103 vs. 114%, medians, p = 0.0087), as well as lower TF levels (440 vs. 672 pg/mL, medians, p = 0.0245) and higher t-PA levels (7.3 vs. 3.8 ng/mL, medians, p = 0.0002), indicative of enhanced fibrinolytic capability, were seen. Younger participants were more sensitive to the orthostatic challenge: CAT-derived endogenous thrombin potentials (ETPs) were only increased in the young (1337 to 1350 nM.min, medians, p = 0.0264) and shortening of PTs was significantly higher in the young vs. older participants (p = 0.0242). Our data suggest that the increased thrombosis propensity in older persons is not primarily attributable to a hyperactive coagulation cascade but may be due to other pathologies associated with aging.

First Comparative Study of the Effectiveness of the Use of Tranexamic Acid against ε-Aminocapróic Acid via the Oral Route for the Reduction of Postoperative Bleeding in TKA: A Clinical Trial

Total primary knee replacement results in significant postoperative bleeding. There are reports that 20 to 50% of the patients require a blood transfusion, which has been related to many complications, resulting in the search for strategies to reduce bleeding. The use of oral antifibrinolytics is becoming a low cost and safe way of achieving this goal. The hypothesis of this study was that the use of oral aminocaproic acid could provide similar results to the use of oral tranexamic acid (TXA). The purpose was to compare the effects of oral aminocaproic acid as a hemostatic agent versus the use of oral TXA administered in multiple doses pre and postsurgery in patients undergoing total primary knee replacement. We enrolled 92 patients that were randomly divided into two groups: received three doses of aminocaproic acid (2,000 mg per dose) or three doses of oral TXA (1,300 mg per dose). The drugs were administered according to the following schedule: 2 hours before surgery and 6 and 12 hours after surgery. The variables that were analyzed to compare the effectiveness of the hemostatic agents were total blood loss; hidden blood loss; external blood loss; transfusion rate; intraoperative blood loss; decreases in hemoglobin and hematocrit values; surgical drainage output; visual analogue scale; and surgical complications. There were no significant differences between any of the study variables for the group receiving oral aminocaproic acid and the group receiving oral TXA (p > 0.05), with the exception of patients who received TXA, who presented with more adverse events (p = 0.04). Our study showed that the use of oral aminocaproic acid was similar to its counterpart TXA regarding the evaluated parameters. Although patients who received TXA presented an average of 140 mL less blood loss than patients in the ε-ACA group, the difference did not appear to be clinically important, the transfusion rate was very low, and there were no between-group differences in postoperative complications.

Effect of age on the functioning of hemostasis system during hip joint endoprosthesis

The study was performed on 109 osteoarthritis patients who underwent hip joint endoprosthetics; the effect of age on changes in hemostasis system, blood loss level and deep veins thrombosis development in the background of standard prevention with low-molecular heparins were studied. Before the surgery, it was determined that 56 elderly patients (60.3 ± 6.4 years) compared to 53 middle-aged patients (41.8 ± 6.8 years) had a significantly higher initial and postoperative endothelial dysfunction, higher fibrin formation and lower anticoagulant potential; however, it was found that on the background of pharmacological anticoagulant therapy the changes in the hemostasis functioning in elderly patients did not lead to an increase of either blood loss or the number of thromboses.

Comparison of 3 Routes of Administration of Tranexamic Acid on Primary Unilateral Total Knee Arthroplasty: A Prospective, Randomized, Controlled Study

BACKGROUND

The mode of administration for tranexamic acid (TXA) to significantly reduce the decrease in hemoglobin (Hb), number of transfusions, relevant costs, and side effects in patients undergoing primary unilateral total knee arthroplasty (TKA) has not been resolved.

METHODS

A total of 560 patients undergoing primary unilateral TKA were randomized into 4 groups: intravenous group (140 patients receiving 2 doses of 20 mg/kg intravenous TXA), topical group (140 patients administered 3.0 g topical TXA), oral group (140 patients given 2 doses of 20 mg/kg oral TXA), and a control group (140 patients not given TXA). The primary outcomes included postoperative 48-hour Hb loss and drainage volume, number of transfusions, transfusion and TXA costs, and thromboembolic complications. Secondary outcomes were postoperative inpatient time and wound healing 3 weeks after TKA.

RESULTS

Baseline data among the 4 groups were similar. The 48-hour Hb loss and drainage volume in the intravenous, topical, and oral groups were significantly less (P < .05) than those in the control group, and the latter had significantly more transfusions and transfusion costs than the other 3 groups (P < .05). The TXA cost was lowest in the oral group compared with that in the topical and intravenous groups (P < .05). No differences in thromboembolic complications, postoperative inpatient time, or wound healing were observed among the groups. However, wound dehiscence and continuous wound discharge occurred in the topical group.

CONCLUSION

All the 3 modes of TXA administration significantly reduced postoperative Hb loss, the number of transfusions, and transfusion costs compared with those in the control group. No pulmonary embolism or infection was observed. Oral TXA is recommended because it provided a similar clinical benefit and resulted in the lowest TXA cost compared with the other 2 modes of TXA administration.

Does tranexamic acid reduce blood loss during head and neck cancer surgery?

Background and Aims:

Transfusion of blood and blood products poses several hazards. Antifibrinolytic agents are used to reduce perioperative blood loss. We decided to assess the effect of tranexamic acid (TA) on blood loss and the need for transfusion in head and neck cancer surgery.

Methods:

After Institutional Review Board approval, 240 patients undergoing supramajor head and neck cancer surgeries were prospectively randomised to either TA (10 mg/kg) group or placebo (P) group. After induction, the drug was infused by the anaesthesiologist, who was blinded to allocation, over 20 min. The dose was repeated every 3 h. Perioperative (up to 24 h) blood loss, need for transfusion and fluid therapy was recorded. Thromboelastography (TEG) was performed at fixed intervals in the first 100 patients. Patients were watched for post-operative complications.

Results:

Two hundred and nineteen records were evaluable. We found no difference in intraoperative blood loss (TA - 750 [600–1000] ml vs. P - 780 [150–2600] ml, P = 0.22). Post-operative blood loss was significantly more in the placebo group at 24 h (P - 200 [120–250] ml vs. TA - 250 [50–1050] ml, P = 0.009), but this did not result in higher number of patients needing transfusions (TA - 22/108 and P - 27/111 patients, P = 0.51). TEG revealed faster clot formation and minimal fibrinolysis. Two patients died of causes unrelated to study drug. Incidence of wound complications and deep venous thrombosis was similar.

Conclusion:

In head and neck cancer surgery, TA did not reduce intraoperative blood loss or need for transfusions. Perioperative TEG variables were similar. This may be attributed to pre-existing hypercoagulable state and minimal fibrinolysis in cancer patients.

Intravenous versus intra-articular tranexamic acid in total knee arthroplasty: A double-blinded randomised controlled noninferiority trial

BACKGROUND

Despite the proven efficacy of both intravenous (IV) and intra-articular (IA) tranexamic acid (TXA) in reducing blood loss during total knee arthroplasty (TKA), the ideal route of administration remained debatable. This study aimed to compare the effect of IV versus IA TXA on transfusion incidences, perioperative blood loss and postoperative lower limb swelling during TKA.

METHODS

One hundred patients were prospectively randomised into two groups: 1) IV TXA; and 2) IA TXA. In both groups, TXA was administered intraoperatively after cementing the prostheses. The perioperative blood loss was calculated using the haemoglobin balance method. The thigh, suprapatellar, and calf girths were measured preoperatively and on postoperative day (POD) 4.

RESULTS

Two patients in the IV group and one patient in the IA group required blood transfusion (p=0.500). The median and interquartile range (IQR) of perioperative blood loss on POD1 and POD4 was 530 (IQR 386,704) and 730 (IQR 523,925) ml for the IV group, compared with 613 (IQR 506,703) and 799 (IQR 563,1067) ml for the IA group (p=0.090 and p=0.232 respectively). The median increment in thigh, suprapatellar, and calf girths were 1.5 (IQR 0, 3.0), 2.0 (IQR 0.5, 4.0) and 0 (IQR 0, 1.0) cm for the IV group, compared to 2.0 (IQR 1.0, 4.0), 2.0 (IQR 0, 4.5) and 0 (IQR 0, 1.5) cm for the IA group (p=0.246, p=0.562, and p=0.937 respectively).

CONCLUSIONS

Both IV and IA TXA had comparable effect on transfusion incidences, perioperative blood loss, and postoperative lower limb swelling during TKA. IA TXA is an alternative to IV TXA.

LEVEL OF EVIDENCE

I.

Intra-articular administration of tranexamic acid in total hip arthroplasty

PURPOSE

To evaluate the effectiveness of intraarticular tranexamic acid (TXA) in reducing blood loss and the need for blood transfusion during total hip arthroplasty (THA).

METHODS

Records of 19 men and 31 women aged 46 to 83 (mean, 62) years who underwent primary THA with intra-articular administration of TXA were reviewed. They were compared with a matched cohort of 17 men and 33 women aged 40 to 87 (mean, 62) years who underwent the same procedure by the same surgeon without use of TXA. Postoperatively, a standard thromboembolic prophylaxis protocol was followed. A serum haemoglobin level of <80 g/l was the trigger for blood transfusion.

RESULTS

The 2 groups were comparable in terms of age, gender, body mass index, side involved, and anaesthesia method. No patient developed infection, wound haematoma, symptomatic deep vein thrombosis, or pulmonary embolism within 30 days. Compared with controls, patients in the TXA group had a higher median postoperative serum haemoglobin level (103 vs. 112 g/l, p=0.013), lower median drop in serum haemoglobin level (31 vs. 20 g/l, p<0.001), lower median total blood loss (900 vs. 575 ml, p<0.001), and lower transfusion rate (32% vs. 10%, p=0.007). The TXA treatment cost S$19.50 per patient, whereas one unit of allogenic blood cost S$123 per patient. Respectively in the control and TXA groups, the mean cost per patient was S$39.36 and S$31.80, indicating a 19% difference.

CONCLUSION

Intra-articular administration of TXA is a cost-effective and safe means to reduce blood loss and the need for blood transfusion during THA, without increasing the risk of thromboembolic events.

Does tranexamic acid alter the risk of thromboembolism after total hip arthroplasty in the absence of routine chemical thromboprophylaxis?

Tranexamic acid (TXA) has been used to reduce blood loss during total hip arthroplasty (THA), but its use could increase the risk of venous thromboembolic disease (VTE). Several studies have reported that TXA does not increase the prevalence of deep vein thrombosis (DVT), but most of those used routine chemical thromboprophylaxis, thereby masking the potential increased risk of TXA on VTE. We wished to ascertain whether TXA increases the prevalence of VTE in patients undergoing THA without routine chemical thromboprophylaxis. We carried out a retrospective case-control study in 254 patients who underwent a primary THA, 127 of whom received TXA (1 g given pre-operatively) and a control group of 127 who did not. All patients had mechanical but no chemical thomboprophylaxis. Each patient was examined for DVT by bilateral ultrasonography pre-operatively and on post-operative days 1 and 7. TXA was found to statistically significantly increase the incidence of total DVT on post-operative day 7 compared with the control group (24 (18.9%) and 12 (9.4%), respectively; p < 0.05) but most cases of DVT were isolated distal DVT, with the exception of one patient with proximal DVT in each group. One patient in the control group developed a non-fatal symptomatic pulmonary embolism (PE). The use of TXA did not appear to affect the prevalence of either proximal DVT or PE.

Cite this article: Bone Joint J 2015; 97-B:458–62.

Topical application of tranexamic acid in primary total hip arthroplasty: a randomized double-blind controlled trial

So far, studies of topical tranexamic acid (TXA) in total hip arthroplasty (THA) were still lacking and controversial. We conducted this randomized double-blind controlled trial which included 101 patients to assess the effect of a high-dose 3g topical TXA in THA. The results showed that 3g topical TXA could significantly reduce transfusions from 22.4% to 5.7% (P<0.05) without increasing the risk of deep vein thrombosis (DVT), pulmonary embolism (PE) and other complications. In addition, topical TXA significantly reduced total blood loss, reduced drain blood loss, and the drops of HB and HCT in topical TXA group were lower than control group. We concluded that 3g topical TXA was effective and safe in reducing bleeding and transfusions in THA.

The effect of tranexamic acid on transfusion rate in primary total hip arthroplasty

Total hip arthroplasty (THA) may produce blood loss requiring allogenic blood transfusion. Recently several authors have reported success decreasing their transfusion rate with tranexamic acid (TXA). We retrospectively reviewed our last 1595 primary THA in 1494 patients looking at whether the patients received TXA via IV infusion, topical application, or neither, and the need for a blood transfusion. Infusion of TXA acid produced a statistically significant difference in transfusion rate (p<0.001) while topical TXA failed to reach statistical significance (P=0.15). The transfusion rate without TXA was 19.86%, 4.39% with TXA infusion (odds ratio=5.36), and 12.86% (odds ratio=1.67) with topical TXA.

Biochemical lung, liver and kidney markers and early death among elderly following hip fracture

INTRODUCTION

In the elderly, hip fracture is a common injury associated with high early mortality dominated by cardiorespiratory and thromboembolic events. Identification of risk factors that can be modified by treatment has caught attention over the last years. This study was conducted to assess biological markers on perioperative organ dysfunction and its association with early mortality within 3 months after surgery.

METHOD

Blood samples were collected before, during and until 4 days after surgery. Analyses on PaO(2), alanine aminotransaminase (ALAT), gamma-glutamyl transpeptidase (g-GT) and creatinine were performed and used as markers on lung, liver and kidney functions.

PATIENTS

Three hundred and two patients over 75 years of age with acute dislocated hip fracture were consecutively enrolled from two hospitals in Norway.

RESULTS

We found a positive correlation between the plasma levels of ALAT, creatinine and death, and an inverse relationship between PaO(2) and death. After controlling for confounding factors such as sex, age and comorbidity, ALAT and creatinine levels were shown to be significantly and independently related to risk for fatal outcome.

CONCLUSION

Our results provide data on clinically important biomarkers in patients undergoing hip fracture surgery. We suggest a stronger emphasis on monitoring and correcting these biomarkers when possible.

Markers of thrombin generation during resurfacing and noncemented total hip arthroplasty: a pilot study

BACKGROUND

Hip resurfacing arthroplasty (HRA) could be associated with an increased risk of deep vein thrombosis (DVT) compared to traditional noncemented THA because it involves greater dissection, increased kinking and distortion of the femoral vessels, takes longer to perform, and involves insertion of some cement into the femur.

QUESTIONS/PURPOSES

Does HRA lead to greater risk of thromboembolism compared with noncemented THA?

METHODS

We prospectively studied 20 patients receiving HRA and 20 receiving THA. All patients were younger than 67 years old and were similar in height, weight, American Society of Anesthesiologists status, and gender mix. Patients undergoing HRA were younger (mean, 50 versus 59 years), their surgery was longer (mean, 87 versus 65 minutes), and they required more crystalloid during surgery (mean, 2160 versus 1662 mL). Radial artery blood samples were taken at six events during surgery and assayed for prothrombin fragment F1 + 2 and thrombin-antithrombin III complex (TAT) using enzyme-linked immunosorbent assays.

RESULTS

We observed no differences in the intraoperative increases in F1 + 2 and TAT between the two groups and no differences in surgical events.

CONCLUSION

Based on these data, HRA and THA should have similar risk of thromboembolism as THA based on the parameters we measured.

LEVEL OF EVIDENCE

Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

The effect of an intravenous bolus of tranexamic acid on blood loss in total hip replacement

Tranexamic acid is a fibrinolytic inhibitor which reduces blood loss in total knee replacement. We examined the effect on blood loss of a standardised intravenous bolus dose of 1 g of tranexamic acid, given at the induction of anaesthesia in patients undergoing total hip replacement and tested the potential prothrombotic effect by undertaking routine venography. In all, 36 patients received 1 g of tranexamic acid, and 37 no tranexamic acid. Blood loss was measured directly per-operatively and indirectly post-operatively.

Tranexamic acid reduced the early post-operative blood loss and total blood loss (p = 0.03 and p = 0.008, respectively) but not the intraoperative blood loss. The tranexamic acid group required fewer transfusions (p = 0.03) and had no increased incidence of deep-vein thrombosis. The reduction in early post-operative blood loss was more marked in women (p = 0.05), in whom this effect was dose-related (r = −0.793).

Our study showed that the administration of a standardised pre-operative bolus of 1 g of tranexamic acid was cost-effective in reducing the blood loss and transfusion requirements after total hip replacement, especially in women.

Delayed presentation of pulmonary polymethylmethacrylate emboli after percutaneous vertebroplasty

STUDY DESIGN

Literature review concerning pulmonary embolism of polymethylmethacrylate (PMMA) material following percutaneous vertebroplasty and a report on 2 new cases.

OBJECTIVE

To inform clinicians about delayed clinical manifestation of pulmonary embolism of polymethylmethacrylate material after percutaneous vertebroplasty, pathophysiology, precautions, and therapeutic management of this complication.

SUMMARY OF BACKGROUND DATA

Percutaneous vertebroplasty is a minimal invasive intervention used to treat vertebral fractures, which yields good therapeutic results and rarely produces complications. Nevertheless, serious complications may occur. Pulmonary PMMA embolism, which has been recently reported in some cases, is one of these.

METHODS AND RESULTS

We report on 2 cases of pulmonary embolism of PMMA material after percutaneous vertebroplasty. In the case of a 45-year-old female patient, symptoms of pulmonary embolism arose with a delay of 3 days following percutaneous vertebroplasty. A therapy with low-molecular-weight heparin, Enoxaparin, enabled recovery from pulmonary failure. The second case occurred without detection of any cement leakage into the paravertebral venous system, neither intraoperatively nor perioperatively. The existence of PMMA in pulmonary vessels was detected 1 year later and remained asymptomatic.

CONCLUSION

These 2 cases allow us to conclude that the risk of pulmonary embolism of PMMA might be underestimated. We propose routine chest radiograph following every vertebroplasty, in order to detect pulmonary PMMA embolism and thereby prevent serious delayed cardiopulmonary failures.

Tranexamic acid reduces postoperative blood loss in cementless total hip arthroplasty

BACKGROUND

Tranexamic acid, an inhibitor of fibrinolysis that blocks the lysine-binding site of plasminogen to fibrin, has been reported to reduce intraoperative and postoperative blood loss in patients undergoing total hip arthroplasty with cement. However, there have been few reports describing the effects of tranexamic acid on blood loss during and following total hip arthroplasty without cement.

METHODS

We investigated the effects of tranexamic acid in twenty-one patients who underwent staged bilateral total hip arthroplasty without cement for the treatment of osteoarthritis of the hip. The average interval between the two procedures was 16 +/- 16 months. On one side, 1000 mg of tranexamic acid was administered intravenously five minutes before the skin incision. On the other side, tranexamic acid was not administered. Baseline hemoglobin and hematocrit values were obtained three weeks before each arthroplasty. The volume of postoperative blood loss was recorded at two-hour intervals for the first twelve hours and then again at twenty-four hours, and the values were compared between the two groups.

RESULTS

The total intraoperative blood loss in the tranexamic acid group (607 +/- 298 mL) was similar to that in the control group (633 +/- 220 mL). The postoperative blood loss in the tranexamic acid group was significantly lower than that in the control group at all time-points during the first twenty-four hours (p < 0.001 for all comparisons). The greatest reduction in blood loss was observed during the first four hours after surgery in the tranexamic acid group (p < 0.01).

CONCLUSIONS

In patients undergoing total hip arthroplasty without cement, preoperative administration of tranexamic acid is associated with decreased postoperative blood loss during the first twenty-four hours, especially during the first four hours after surgery.

The procoagulant potential of environmental particles (PM10)

BACKGROUND AND AIMS

Epidemiology studies have shown that cardiovascular (CV) disease is primarily responsible for the mortality associated with increased pulmonary environmental particle (PM10) exposure. The mechanisms involved in PM10 mediated CV effects are unknown although changes in plasma viscosity and in the homoeostasis of blood coagulation have been implicated. It was hypothesised that PM10 exposure would result in an inflammatory response and enhance the activation of the extrinsic coagulation mechanisms in pulmonary and vascular cells in culture.

METHODS

Primary human monocyte derived macrophages and human umbilical cord vein endothelial, human alveolar type II epithelial (A549), and human bronchial epithelial (16HBE) cells were tested for their inflammatory and procoagulant response to PM10 exposure. IL-8, tissue factor (TF), and tissue plasminogen activator (tPA) gene expression and protein release, and coagulation enhancing ability of culture media were determined 6 and 24 hours following exposure.

RESULTS

The culture media from macrophages and 16HBE bronchial epithelial cells, but not A549 cells, exposed to PM10 had an enhanced ability to cause clotting. Furthermore, H2O2 also increased the clotting activity. Apoptosis was significantly increased in macrophages exposed to PM10 and LPS as shown by annexin V binding. TF gene expression was enhanced in macrophages exposed to PM10, and HUVEC tissue factor and tPA gene and protein expression were inhibited.

CONCLUSIONS

These data indicate that PM10 has the ability to alter macrophage, epithelial, and endothelial cell function to favour blood coagulation via activation of the extrinsic pathway and inhibition of fibrinolysis pathways.

Relationship between intraoperative transoesophageal echocardiography findings and perfusion lung scintigraphy results on first postoperative day

BACKGROUND

Although intraoperative transoesophageal echocardiography (TOE) has been used to detect the occurrence of echogenic macro- and/or microembolic phenomena during total hip arthroplasty (THA), no direct correlation between macroembolism and the formation of pulmonary embolism (PE) has been conclusively determined in early postoperative periods after THA.

METHODS

Sixty-two patients scheduled for primary THA were enrolled in this study. Intraoperative TOE images were continuously recorded on videotape and the echogenic events were evaluated throughout surgery. Perfusion lung scintigraphy was performed on the first postoperative day (POD1).

RESULTS

Perfusion lung scintigraphy revealed the existence of PE in nine (15%) of the 62 patients who underwent THA: five (25%) of 20 patients with cemented THA and four (10%) of 42 patients with non-cemented THA. The grading score of intraoperative TOE findings, including the amount of echogenic particles in right atrium, the longest time of echogenesis and the diameter of the largest echogenic particles, did not differ between the groups with and without PE. The sensitivity, specificity, and positive and negative predictive values for the detection of echogenic macroemboli for the prediction of the development of PE on POD1 were 0.78, 0.60, 0.25 and 0.94, respectively.

CONCLUSION

Intraoperative TOE monitoring did not predict the occurrence of PE on POD1.

Tranexamic acid reduces blood loss after cementless total hip arthroplasty-prospective randomized study in 40 cases

We investigated the effects of tranexamic acid in 40 patients who had received cementless total hip arthroplasty (THA) in a prospective, randomized study. In 20 patients, 1000 mg of whole-body tranexamic acid was administered intravenously 5 min before the operation started. The other 20 patients served as a control group and were operated on without tranexamic acid. Perioperative blood loss was similar in the tranexamic acid group and in the control group. Postoperative blood loss of the tranexamic acid group was significantly less than that of the control group at 2, 4, 6, 8, 10, and 12 h. Regarding time-related changes of postoperative blood loss, significant reduction was observed during the first 2 h after surgery in the tranexamic acid group ( P<0.001). After the first 2 h, there was no significant difference between the tranexamic acid group and the control group. Preoperative administration of tranexamic acid decreased postoperative blood loss until 12 h and total bleeding in cementless THA by reduction of blood loss during the first 2 h after surgery.

Platelet activation after in vitro contact with seven acrylic bone cements

Seven acrylic bone cements were evaluated: Cemex Rx (Tecres S.p.a., Italy), Cemex Isoplastic (Tecres S.p.a., Italy), Zimmer Low Viscosity Cement (L.V.C., Zimmer, IN, USA), Zimmer bone cement - dough type (Zimmer, IN, USA), CMW (DePuy International Ltd., UK), Cerim LT (Cremascoli S.r.l., Italy), and Palacos (Merck, Wehreim, Germany). The cements after polymerization were put in contact in vitro with platelet-rich plasma. Plasma in contact only with siliconated glass was used as the negative control. After contact, platelet number, beta-thromboglobulin (beta-TG), and transforming growth factor-beta1 (TGF-beta1) were determined. The Wilcoxon signed rank test showed Palacos R and L.V.C. induced a significant decrease of platelet number compared with the negative control. All cements determined a significant increase in beta-TG. CMW 3, Palacos, L.V.C., and Zimmer dough type determined a significant increase in TGF-beta1 compared with the negative control.

Thrombomodulin expression in endothelial cells after contact with bone cement

The expression of thrombomodulin after contact with CMW 1 bone cement extracts was studied in human umbilical vein endothelial cells. Cement extracts after 1 h and 7-day curing induced no significant variations in thrombomodulin antigen levels and in mRNA expression. Significant increase of thrombomodulin was observed when endothelial cells were treated with all-trans retinoic acid (ATRA). ATRA induced the increase of thrombomodulin also in cells incubated with cement extracts. These results suggest that CMW 1 bone cement does not impair the expression of thrombomodulin in endothelial cells.

Platelet release of transforming growth factor-beta and beta-thromboglobulin after in vitro contact with acrylic bone cements

Three methacrylate-based bone cements used for the fixation of joint prostheses were evaluated: Sulfix-60 (Sulzer Orthopedic Inc., Baar, Switzerland). CMW1 (DePuy International Ltd., England). and CMW2 (DePuy International Ltd., England). The cements after polymerization were put in contact in vitro with platelet-rich plasma. Plasma, in contact only with siliconized glass, was used as a negative control. After contact, platelet number. beta-thromboglobulin (beta-TG), and transforming growth factor-beta1 (TGF-beta1) were determined. The Student's paired t test showed that the ccments induced no significant modifications of platelet number. CMWI and Sulfix-60 determined a significant increase in beta-TG compared with the negative control. All cements determined a significant increase in TGF-beta1. Significant differences were also seen in the levels of beta-TG and TGF-beta1 between cements with a content of benzoyl peroxide < 1 (Sulfix-60) and those with a content > 1 (CMW1 and CMW2). The cement with zirconium dioxide (Sulfix-60) produced higher levels of beta-TG and TGF-beta1, compared to those with barium sulphate (CMW1 and CMW2). In conclusion, all the cements induced the secretion of TGF-beta1 CMW1 and Sulfix-60 determined also a significant release of beta-TG. Platelet activation induced by the cements from one side could contribute to the pathogenesis of deep venous thrombosis, that often occurs after prosthetic implant and is caused also by other factors, including surgical trauma and venous stasis. From the other side, activated platelets can release growth factors favoring bone formation.

Pathophysiology of venous thromboembolism

Venous thromboembolism remains an important cause of morbidity and mortality for surgical and non-surgical patients, and its pathophysiology in acutely ill, non-surgical patients is not well understood. The clinically silent nature of thromboembolism makes it a significant threat to hospital patients.

Fibrin monomer could be a useful predictor of pulmonary embolism after total hip arthroplasty: preliminary report

We examined 17 total hip arthroplasty patients in order to develop a method for the predictive diagnosis of pulmonary embolism (PE) after joint arthroplasty. Scintigraphy revealed the presence of PE in 4 patients. Prothrombin time (PT), activated partial thromboplastin time (aPTT), antithrombin III (ATIII), and thrombin-AT III complex (TAT) did not show significant differences between patients with and without PE. D-dimer 7 days after surgery showed significant differences between patients with and without PE. Fibrin monomer (FM) increased sharply after surgery, and it was significantly different between the patients with and without PE immediately after surgery and 2 days after surgery. Our findings suggest the importance of FM in the predictive diagnosis of pulmonary embolism after total hip arthroplasty, and 40 microg/ml or higher levels with our measurement method could represent a high-risk condition.

Thrombotic complications in beating heart operations

BACKGROUND

Off-pump coronary artery operations have recently gained popularity among the community of cardiac surgeons. Because the use of cardiopulmonary bypass is avoided, full anticoagulation is generally not sought to decrease perioperative blood loss and transfusion needs. Traditionally, patients undergoing coronary artery bypass operations with cardiopulmonary bypass are not considered at risk of having venous or arterial thromboembolic complications, and prophylaxis is generally not recommended.

METHODS AND RESULTS

We have reviewed our experience with off-pump coronary bypass operations, focusing on thromboembolic complications with clinical manifestations, and compared these findings with our experience with cardiopulmonary bypass operations. In our series of 500 off-pump cases, thromboembolic complications occurred in 1%, causing death in 1 patient, whereas in a contemporary cohort of 1476 patients operated on with cardiopulmonary bypass, thromboembolic complications resulted in stroke in 0.5% of the cases. This difference did not reach statistical significance.

CONCLUSIONS

Thromboembolic complications in off-pump coronary bypass operations are comparable with those in cardiopulmonary bypass operations. Although the prevalence of this complication remains low, the associated morbidity should lead to reconsideration of prophylactic measures.

Preoperative platelet-rich plasmapheresis and hemodilution with an autotransfusion device in total hip replacement surgery

The effectiveness of both preoperative autologous donation (PAD) and intraoperative autotransfusion (IAT) with an autotransfusion device has recently been questioned. Preoperative apheresis, with separation of concentrated platelet rich-plasma (c-PRP) and erythrocyte concentrate (ERC), represents an aggressive use of the autotransfusion device. Can such a procedure replace PAD in total hip replacement surgery (THR)? Eighty patients undergoing THR were investigated in a prospective and randomized study. Forty patients underwent PAD, and 2 units of ERC + plasma were retrieved within 4 weeks preoperatively. Another 40 patients underwent an immediately preoperative apheresis with a concomitant hemodilution with 4% albumin, retrieving c-PRP (30% of the platelet pool) and 2 units of ERC. Both groups used IAT up to 2 hours postoperatively, with 3% dextran-60 as a plasma substitute according to our standard of care. There were no differences in blood loss, B-hemoglobin or allogeneic transfusions between the groups: 85% of the patients did not receive allogeneic blood. Both apheresis and reinfusion of c-PRP had minor impact on the coagulation parameters. Platelet count increased slightly but significantly (P<0.05) from 154 to 179 x 10(9)/L after the c-PRP at wound closure. Preoperative apheresis with an autotransfusion device, separating platelet-rich plasma and erythrocyte concentrate, is a useful alternative for patients who are unable to utilize the PAD technique for either religious or practical reasons.

Thromboelastography for monitoring prolonged hypercoagulability after major abdominal surgery

Despite clinical and laboratory evidence of perioperative hypercoagulability, there are no consistent data evaluating the extent, duration, and specific contribution of platelets and procoagulatory proteins by in vitro testing. We tested the hypothesis that the parallel use of standard and abciximab-cytochalasin D-modified thromboelastography (TEG) can assess 7 days' postoperative hypercoagulability and can estimate the independent contribution of procoagulatory proteins and platelets. Thromboelastograms were performed before surgery, at the end of surgery, 6 h after surgery, and on postoperative days 1, 2, 3, and 7; they were analyzed for the reaction time and the maximal amplitude (MA). We calculated the elastic shear modulus of standard MA (G(t)) and modified MA (G(c)), which reflect total clot strength and procoagulatory protein component, respectively. The difference was an estimate of the platelet component (G(p)). There was a 10% perioperative increase of standard MA, corresponding to a 50% increase of G(t) (P < 0.0001) and an 86%-90% contribution of the calculated G(p) to G(t). We conclude that serial standard and modified thromboelastography may reveal prolonged postoperative hypercoagulability and the independent contribution of platelets and procoagulatory proteins to clot strength.

IMPLICATIONS

Postoperative hypercoagulability, occurring for at least 1 wk after major abdominal surgery, may be demonstrated by standard and modified thromboelastography. This hypercoagulability is not reflected by standard coagulation monitoring and seems to be predominantly caused by increased platelet reactivity.

No effect of methacrylate-based bone cement CMW 1 on the plasmatic phase of coagulation, red blood cells and endothelial cells in vitro

The compatibility of a methacrylate-based bone cement (CMW 1, DePuy International Ltd, England) used for the fixation of joint prostheses was evaluated on plasma, an erythrocyte suspension and cultured human endothelial cells. The extract of the cement was tested, following 1 hour and 7 days of curing. After the contact in vitro of the extract with plasma, activated partial thromboplastin time, antithrombin III, thrombin-antithrombin complexes and fibrin degradation products were assayed. Hemolytic activity was tested by adding the cement extracts to a suspension of erythrocytes. After 4 hours of incubation at 37 degrees C, the hemoglobin concentration was determined on the supernatants by the colorimetric method. The effect of the cement on tissue factor and thrombomodulin production was evaluated on human umbilical vein endothelial cell cultures. Tissue factor was determined in cell lysates by enzyme immunoassay, following 4 hours' incubation of cultures with the cement extract. Thrombomodulin was assayed in cell lysates by enzyme immuno assay, after 24 hours' incubation with the cement extract. The response to all trans-retinoic acid (ATRA) was tested. The cement caused no significant modifications of the coagulation tests, had no hemolytic activity, did not determine tissue factor production and did not modify thrombomodulin, compared to the negative control. The response to stimulation with ATRA was similar to that of the negative control. We conclude that the cement extract does not affect the plasmatic phase of coagulation, has no effect on erythrocytes, does not induce the expression of procoagulant activity by endothelial cells and does not impair their antithrombotic property, within the limits of the tests performed.

Tranexamic acid reduces blood loss in total hip replacement surgery

Intraoperatively administered, tranexamic acid (TA) does not reduce bleeding in total hip replacement (THR). Therefore, its prophylactic use was attempted in the present study because this has been shown to be more effective in cardiac surgery. We investigated 40 patients undergoing THR in a prospective, randomized, double-blinded study. Twenty patients received TA given in two bolus doses of 10 mg/kg each, the first just before surgical incision and the second 3 h later. In addition, a continuous infusion of TA, 1.0 mg. kg(-1). h(-1) for 10 h, was given after the first bolus dose. The remaining 20 patients formed a control group. Both groups used preoperative autologous blood donation and intraoperative autotransfusion. Intraoperative bleeding was significantly less (P: = 0.001) in the TA group compared with the control group (630 +/- 220 mL vs 850 +/- 260 mL). Postoperative drainage bleeding was correspondingly less (P: = 0.001) (520 +/- 280 vs 920 +/- 410 mL). Up to 10 h postoperatively, plasma D-dimer concentration was halved in the TA group compared with the control group. One patient in each group had an ultrasound-verified late deep vein thrombosis. In conclusion, we found TA, administrated before surgical incision, to be efficient in reducing bleeding during THR.

IMPLICATIONS

In a prospective, double-blinded study of 40 patients undergoing total hip replacement, the preoperative administration of tranexamic acid reduced bleeding by 35%, probably by decreasing induced fibrinolysis. Whether tranexamic acid therapy can replace predonation of autologous blood or intraoperative autotransfusion requires further study.

Markers of activated hemostasis and fibrinolysis in patients with pulmonary malignancies: comparison of plasma levels in central venous and pulmonary venous blood

Malignancy frequently is accompanied by activated coagulation and fibrinolysis indicating a hypercoagulable state. The purpose of our study was to estimate the contribution of local tumor-induced mechanisms to the activation of hemostasis and fibrinolysis. In a prospective study, we compared the plasma levels of thrombin-antithrombin complexes, prothrombin fragment 1+2, and D-dimers in blood samples that simultaneously were drawn from the superior vena cava and the pulmonary vein of a tumor-bearing pulmonary lobe. Samples from the superior vena cava were drawn before operation and served as controls. After thoracotomy, a second group of samples was simultaneously taken from the pulmonary veins of the tumor-bearing lobe and the superior vena cava. Forty-five patients with pulmonary malignancies were included (25 adenocarcinomas and 20 squamous cell carcinomas). There were no significant differences of thrombin-antithrombin complexes, prothrombin fragment 1+2, and D-dimers levels in patients suffering from adenocarcinoma and from squamous cell carcinoma. Intraoperatively, prothrombin fragment 1+2 and D-dimers levels were markedly increased when compared with the preoperative values (p<0.0001). There was no increase of thrombin-antithrombin complexes levels due to the operative traumatization. Prothrombin fragment 1+2, thrombin-antithrombin complexes, and D-dimers plasma levels were significantly higher in the pulmonary venous blood than in the blood simultaneously drawn from the superior vena cava (p<0.0001). Our findings indicate that malignant lung tumors directly contribute to the activation of hemostasis and fibrinolysis in these clinical settings.