Heparin-induced thrombocytopenia

Type II Heparin-Induced Thrombocytopenia: An Underrecognized Cause of Dialysis Catheter Dysfunction - A Case Report

Heparin-induced thrombocytopenia (HIT) is categorized into type 1 and type 2. It causes a decrease in platelet count during or shortly after exposure to heparin. Type 1 is mild and has a non-immune mechanism. Type 2 is a hypercoagulable state resulting from anti-heparin platelet factor 4 (PF4) IgG antibodies. These antibodies cause the activation of endothelium and thrombin generation. Type 2 HIT is complicated by life-threatening thromboembolic events such as deep venous thrombosis, pulmonary embolism, and myocardial infarction. HIT remains an under-recognized cause of dialysis catheter dysfunction and thrombosis. We present a case of a 66-year-old male with recurrent dialysis catheter thrombosis secondary to Type 2 HIT. Avoiding heparin-based dialysis or switching to non-heparin-based anticoagulation or peritoneal dialysis are the possible management strategies for such patients.

Construction of an Antithrombotic and Anti-Inflammatory Polyethersulfone Membrane

In addition to being the core factor in thrombosis, thrombin is involved in various inflammatory disease responses, but few studies have examined whether and how it is involved in membrane-related inflammation. In this study, the thrombin inhibitor dabigatran is used to modify a polyethersulfone dialysis membrane. The modified membrane shows good hydrophilic properties and dialysis performance. It reduces the thrombin level in a targeted manner, thereby significantly inhibiting coagulation factor activation (based on the prothrombin time, international normalized ratio, activated partial thromboplastin time and thrombin time) and reducing the fibrinogen level and platelet adhesion. On thromboelastography, it shows excellent dynamic antithrombotic capacity. The modified membrane inhibited membrane-related inflammation by inhibiting the production of the inflammatory mediators C-reactive protein (CRP), interleukin-6 (IL-6), and interleukin-1β (IL-1β) via the thrombin/complement C5a pathway. Moreover, it is found to be safe in an in vivo study. Thus, the dabigatran-modified polyethersulfone membrane may reduce dialysis-related complications through its dual antithrombotic and anti-inflammatory effects.

Dilemmas in the Choice of Adequate Therapeutic Treatment in Patients with Acute Pulmonary Embolism—From Modern Recommendations to Clinical Application

Pulmonary thromboembolism is a very common cardiovascular disease, with a high mortality rate. Despite the clear guidelines, this disease still represents a great challenge both in diagnosis and treatment. The heterogeneous clinical picture, often without pathognomonic signs and symptoms, represents a huge differential diagnostic problem even for experienced doctors. The decisions surrounding this therapeutic regimen also represent a major dilemma in the group of patients who are hemodynamically stable at initial presentation and have signs of right ventricular (RV) dysfunction proven by echocardiography and positive biomarker values (pulmonary embolism of intermediate–high risk). Studies have shown conflicting results about the benefit of using fibrinolytic therapy in this group of patients until hemodynamic decompensation, due to the risk of major bleeding. The latest recommendations give preference to new oral anticoagulants (NOACs) compared to vitamin K antagonists (VKA), except for certain categories of patients (patients with antiphospholipid syndrome, mechanical valves, pregnancy). When using oral anticoagulant therapy, special attention should be paid to drug–drug interactions, which can lead to many complications, even to the death of the patient. Special population groups such as pregnant women, obese patients, patients with antiphospholipid syndrome and the incidence of cancer represent a great therapeutic challenge in the application of anticoagulant therapy. In these patients, not only must the effectiveness of the drugs be taken into account, but great attention must be paid to their safety and possible side effects, which is why a multidisciplinary approach is emphasized in order to provide the best therapeutic option.

Acetylation Modification, Characterization, and Anticomplementary Activity of Polysaccharides from Rhododendron dauricum Leaves

This study focuses on the acetylation modification of polysaccharides from Rhododendron dauricum leaves (RDPs) with a high degree of substitution (DS) and then discusses their characterization and biological activity. The optimum acetylation conditions of RDPs were optimized by response surface methodology, which were reaction time 3 h, reaction temperature 50 °C, and the liquid-solid ratio 16 mL/g. Under the optima schemes, two eco-friendly acetylated polysaccharides from R. dauricum leaves (AcRDP-1 with DS of 0.439 ± 0.025 and AcRDP-2 with DS of 0.445 ± 0.022) were prepared. The results of structural characterization showed that the AcRDP-1 (9.3525 × 10³ kDa) and AcRDP-2 (4.7016 × 10³ kDa) were composed of mannose, glucose, galactose, and arabinose with molar ratios of 1.00:5.01:1.17:0.15 and 1.00:4.47:2.39:0.88, respectively. Compared with unmodified polysaccharides, the arabinose content and molecular weight of the two acetylated polysaccharides decreased, and their triple helix conformation disappeared, and further improved their anticomplementary activity. The two acetylated polysaccharides showed stronger a complement inhibition effect than the positive drug by blocking C2, C3, C4, C5, C9, and factor B targets in the classical and alternative pathways. This research indicated that acetylation modification could effectively enhance the anticomplementary activity of RDPs, which is beneficial for the development and utilization of R. dauricum leaves.

Monitoring coagulation-fibrinolysis activation prompted timely diagnosis of hemophagocytic lymphohistiocytosis-related disseminated intravascular coagulation

Background

Timely diagnosis of disseminated intravascular coagulation (DIC) in hemophagocytic lymphohistiocytosis (HLH) patients is crucial but challenging, as HLH interferes with the results of the laboratory tests included in the DIC score system.

Case presentation

Here, we reported a case of lymphoma-associated HLH, in which coagulation-fibrinolysis activation /inhibition markers (TAT, tPAIC, and PIC), prompted timely diagnosis of early stage DIC (initial phase of microvascular thrombosis, yet non-overt), prior to the development of organ failures and/or bleedings.

Conclusions

This report highlights the importance of the implementation of new biomarkers (such as TAT, tPAIC, and PIC), into the diagnostic work-up for coagulation disorders. These biomarkers are directly suggestive of microthrombus formation, therefore they can be of paramount importance in diagnosing DIC with complicated etiologies, such as hematological diseases-related DIC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00338-y.

Survey of Practice Pattern in Patients With Heparin-Induced Thrombocytopenia Requiring Cardiopulmonary Bypass

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse reaction to heparin. Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) are routinely anticoagulated with heparin before the initiation of bypass. Heparin is contraindicated, however, in patients with acute HIT, and alternatives to routine practice are often used. While guidelines have recently been published addressing this topic 10, there remains variance between institutions in how these cases are treated. Our goal was to better delineate practice trends in the diagnosis and management of HIT patients requiring CPB.

METHODS

We surveyed members of the Society of Cardiovascular Anesthesiologists (SCA) and the American Society for Extracorporeal Technology (AmSECT) using an online survey tool.

RESULTS

We received 304 completed surveys (5.8% response rate), 75% completed by an anesthesiologist, and 24% by a perfusionist. The majority of respondents used clinical history and/or antibody testing (71% and 63%, respectively) to diagnose HIT. Seventy-five percent of respondents reported using an institutional protocol for HIT-CPB cases. Most respondents (89%) reported having at least 1 case in the last 3 years, with a total case experience of at least 785 cases (785 = the minimum number of cases in each case volume category × the number of respondents choosing that category). The strategy recommended in published guidelines, bivalirudin, was the most commonly reported alternative anticoagulation strategy (75%) used by respondents in HIT cases, with most (83%) using the activated clotting time (ACT) to monitor anticoagulation.

CONCLUSIONS

Most responding SCA and AmSECT members reported that their institution used a protocol or guideline for HIT/CPB cases, and most guidelines directed the use of bivalirudin as an alternative anticoagulant. Various other methods such as plasmapheresis are also being used with success in this patient population. Further research, including comparison studies of alternative anticoagulant strategies, is required to elucidate the best approach to these difficult cases.

Dabigatran Use after Argatroban for Heparin-induced Thrombocytopenia with Thrombosis: A Case Series and Literature Review

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is immune-mediated thrombotic thrombocytopenia following the use of heparin, which contributes to a high limb-amputation rate and mortality if not appropriately handled. There is growing evidence suggesting that novel oral anticoagulants (NOACs) may be effective for treating HIT.

METHODS

We described five rare cases of patients with HIT associated with deep vein thrombosis treated with dabigatran, a member of NOACs. We also reviewed representative cases and literature investigating the use of NOACs to treat patients with HIT to further discuss the efficacy and safety.

RESULTS AND CONCLUSIONS

Following the treatment of dabigatran after argatroban, the platelet count of patients with HIT gradually elevated and reached the normal range eventually. There was no incidence of new symptomatic, objectively-confirmed arteriovenous thromboembolism observed within the 90-day-period follow up. The patient in case 3 presented with gastric bleeding after dabigatran treatment and died in the end. The results suggested that dabigatran use after argatroban may be effective in the treatment of patients with HIT. However, safety should be reconsidered since severe complications were observed in case 3.

Oral Factor Xa (FXa) Inhibitors for Treatment of Heparin-induced Thrombocytopenia (HIT)

Background::

Heparin is the most commonly used injectable anticoagulant for many indications, ranging from the treatment of atrial fibrillation to the prevention of clotting in patients undergoing surgery. Currently, only argatroban and bivalirudin are FDA approved for the management of heparin induced thrombocytopenia (HIT) in the United States, both of which are direct thrombin inhibitors. The agents being reviewed, apixaban and rivaroxaban, are oral direct factor Xa (FXa) inhibitors. Currently, neither has FDA approval for use in HIT. The objective of this review is to summarize the current evidence available regarding the use of oral factor Xa inhibitors for the treatment of HIT.

Methods::

A literature search was conducted using Medline and Ovid Embase. Search terms included heparin-induced thrombocytopenia, HIT, apixaban, rivaroxaban, Xa Inhibitor, direct thrombin inhibitor, NOAC, and DOAC. Studies and case reports were included if they evaluated the efficacy and safety of oral FXa inhibitors for the treatment of HIT. Additional literature and case reports were found through bibliographic review.

Results and Discussion:

Currently, available literature includes an in vitro study with apixaban, case reports, and retrospective and prospective cohort studies. The in vitro study evaluated the interaction between apixaban and platelets in the presence of HIT antibodies, which assessed its potential for use in HIT management. Fourteen case reports and one case series were also identified, of which six described treatment with apixaban and eight with rivaroxaban. Lastly, four cohort studies were published evaluating the use of direct acting oral anticoagulants (DOACs), including oral factor Xa inhibitors in patients with HIT. Although there are no published randomized control trials evaluating the use of FXa inhibitors in the management of HIT, there are several findings that may guide clinicians on the use of these agents in practice.

Conclusion::

As indicated by the case reports, case series and cohort studies detailing clinical use and described in this manuscript, there are data and positive patient outcomes that support the potential use of these agents for HIT, and are an impetus for future studies.

Heparin-induced thrombocytopenia in renal insufficiency undergoing dialysis and percutaneous coronary intervention after acute myocardial infarction: A case report

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is a rare complication of heparin therapy, and is characterized by arteriovenous thrombosis and bleeding events. The incidence of HIT after percutaneous coronary intervention (PCI) in patients with myocardial infarction complicated with renal failure is rarely reported.

CASE SUMMARY

We report a 73-year-old man with acute myocardial infarction and renal failure who underwent hemodialysis and PCI, and developed a progressive decline in platelets and subcutaneous hemorrhage of both upper limbs after heparin treatment. In addition to a gradual decrease in platelets, the patient’s 4T's score was 7, and HIT antibody was positive, confirming the diagnosis of HIT.

CONCLUSION

Patients receiving heparin combined with antiplatelet therapy should be monitored closely, especially for their platelet count. In the case of thrombo-cytopenia, HIT should be highly suspected. When the diagnosis of HIT is confirmed, timely individualized treatment should be delivered.

Electrophysiological Procedures in Patients With Coagulation Disorders - A Systemic Review

Catheter ablation (CA) is considered first-line treatment for many patients with symptomatic arrhythmias. Indications for CA are constantly increasing, as is the number of procedures. Although CA is nowadays regarded a safe procedure, there is a risk of complications, including both bleeding- and thrombosis-related events. Several factors contribute to periprocedural risk; of these, patient coagulation status is of considerable clinical relevance. In this context, even a simple procedure poses a considerable challenge in a patient with coagulation disorder. However, the level of evidence regarding CA in patients with coagulation disorders is very low. Neither experts' recommendations nor clinical guidelines have been presented so far. The aim of this article is to analyze potential procedure-related risks and provide clinicians with useful information and practical suggestions regarding optimization of procedural safety in patients with coagulation disorders.

[CME:Heparin-Induced Thrombocytopenia]

CME:Heparin-Induced Thrombocytopenia Abstract. Heparin-induced thrombocytopenia (HIT) is a dangerous, potentially fatal, immunologically mediated side effect of heparin. Typically, five to ten days after heparin exposure there is a decrease in platelet count with a mean of 60 x 109/l. Due to an activation of thrombocytes by HIT antibodies, venous or more rarely arterial thromboses may occur. The diagnosis of HIT includes the calculation of the probability of a HIT using the 4T Score and the laboratory detection of HIT antibodies. The HIT therapy represents the immediate discontinuation of the heparin therapy as well as the beginning of an alternative therapeutic anticoagulation.

Common inflammatory markers after cardiac surgery in infants and their relation to blood stream sepsis

Background

Limited information exists on trends of common inflammatory markers after infant heart surgery and their role in identifying post-operative sepsis.

Methods

275 consecutive infants undergoing cardiac surgery (231 with and 44 without Cardiopulmonary Bypass) were studied prospectively. Daily trends (0-4 day post-operative) of leucocyte counts, platelet counts and C-reactive protein were recorded. Association of these trends with early post-operative bloodstream sepsis, Cardiopulmonary Bypass and surgical outcomes were studied.

Observations

Trends of these inflammatory markers were noted. While off-Cardiopulmonary Bypass Surgery, and sepsis were associated with a statisticaly insignificant rise in total leucocyte count peaking on first post-operative day, Cardiopulmonary Bypass exposure was associated with significant decline (p = 0.002), more pronounced with Cardiopulmonary Bypass-exposure exceeding 150 min. Percentage of neutrophils showed a rise (maximum on first post-operative day) but no significant association with sepsis or Cardiopulmonary Bypass.Platelet counts significantly declined after surgery, with nadir on 2^nd POD (p < 0.001), the drop being more marked in patients operated on Cardiopulmonary Bypass (p < 0.005). Counts were significantly lower in patients exposed to >150 min Cardiopulmonary Bypass compared to those with shorter Cardiopulmonary Bypass. Septic patients had significantly lower platelet counts than uninfected patients, decline >2 SD from mean pre-operative level strongly associated with sepsis (p < 0.001).C-Reactive Protein levels rose markedly after surgery, peaking on 2^nd POD; levels were significantly higher if operated on Cardiopulmonary Bypass. Cardiopulmonary Bypass >150 min was associated with lower mean C-Reactive Protein on first post-operative day, but significantly higher values on third and fourth post-operative days, as compared to Cardiopulmonary Bypass <150 min. Comparison of infected versus non-infected patients showed significantly higher mean C-Reactive Protein in the former group.

Conclusion

While leucocyte count, platelet count and C-Reactive Protein emerged as useful markers of post-operative inflammatory response and reaction to Cardiopulmonary Bypass, they proved unsatisfactory predictors of early post-operative sepsis.

Evaluation of the Activity of Heparin Injected into the Fully Implantable Catheter for Chemotherapy (Portocath) between Two Moments of Use

BACKGROUND

The aim of this study is to analyze whether heparin, used as a lock in fully implantable catheter for chemotherapy (portocath), maintains its activity even if it remains in the catheter for a long period of time.

METHODS

According to the institutional protocol, all catheters routinely use the lock solution with 3 mL of heparinized solution after chemotherapy and the time interval between each change as lock in the catheters studied ranged from 7 to 30 days. A total of 25 blood samples from 22 patients with 6 types of neoplasia on chemotherapy or not were collected according to routine, and the 10 mL of liquid contained in the first aspirated reservoir/catheter (corresponding to the lock of the last section), were sent for laboratory analysis for prospectively studied with the following tests: anti-Xa, partially activated thromboplastin time (APTT), thrombin time (TT), reptilase, and thromboelastogram.

RESULTS

Heparin activity was found in 96% of the anti-Xa and APTT tests. In relation to TT, 92% presented activity. The reptilase test was performed on 24 samples with significant time reduction in all of them. In the INTEM stage, the thromboelastometry test showed activity in 92% of samples and in the HEPTEM phase there was reduction in time in all samples. In all samples, the heparin activity was found to be independent of the time of use.

CONCLUSIONS

We can conclude that lock of heparinized solution used in our service in fully implantable central venous catheters for chemotherapy was maintained with active heparin even after a long period of time (up to 30 days), demonstrating that the half-life of the substance within the catheter is greater than its plasma half-life.

Fondaparinux in a critically Ill patient with heparin-induced thrombocytopenia: A case report

RATIONALE

Fondaparinux, as a factor Xa-inhibitor, is used off label to manage heparin-induced thrombocytopenia (HIT), but little experience with HIT patients has been reported in the literature. Moreover, the use of fondaparinux for full anticoagulation in critically ill patients with HIT and renal insufficiency is limited.

PATIENT CONCERNS

A trauma patient, who had received low molecular weight heparin (LMWH) and heparin to treat venous thromboembolism, developed thrombocytopenia and multiple organ dysfunction in the intensive care unit (ICU). Also, her deep venous thromboembolism (DVT) continued to progress.

DIAGNOSIS

The final diagnosis was HIT.

INTERVENTIONS

Fondaparinux was temporarily used for anticoagulation treatment of DVT for 7 days when another anticoagulant (argatroban) was unavailable. Although the patient had kidney dysfunction, a full therapeutic dose of 7.5 mg fondaparinux was administered every morning through subcutaneous injection for consecutive 7 days.

OUTCOMES

The patient's thrombocytopenia and thrombosis were successfully treated without bleeding complications during therapeutic fondaparinux administration.

LESSONS

This is the first case reporting the successful use of fondaparinux for full anticoagulation for DVT in a critically ill patient with HIT and renal insufficiency. Our experience suggests that fondaparinux might be an alternative for anticoagulation treatment in patients with HIT and kidney dysfunction if another anticoagulant (argatroban) is unavailable.

Synthesis and biocompatibility of an argatroban-modified polysulfone membrane that directly inhibits thrombosis

Anticoagulation therapy plays a vital role in the prevention of blood clot formation during hemodialysis and hemofiltration, especially for critical care patients. Here, we synthesized a novel argatroban (Arg)-modified polysulfone (PSf) membrane for anticoagulation. Arg was grafted onto the PSF membrane via chemical modification to increase membrane hydrophilicity. Protein adsorption, coagulation, as well as activation of platelets and complement systems were greatly reduced on the Arg-modified PSf membrane. Thus, the recalcification time and the activated partial thrombin time (APTT) were increased after the modification. In comparison with the pristine PSf membrane, the Arg-modified PSf membrane showed better hemocompatibility and anticoagulation properties, indicating its potential for applications in hemodialysis and hemofiltration. Modification of the PSf membrane has been investigated in attempts to further enhance the anticoagulation properties of the hemodialysis membranes, including a heparin-modified PSf membrane. However, heparin can inhibit plasma-free thrombin, and cause the occurrence of heparin-induced thrombocytopenia (HIT), which increases the risk of bleeding during dialysis in critical care patients. To address this problem, we modified PSf membrane with as a novel direct thrombin inhibitors, argatroban (Arg). It can reversibly bind to thrombin, inhibiting not only the plasma-free thrombin in the blood, but also clot-bound thrombin.

Heparin-Induced Thrombocytopenia: A Comprehensive Clinical Review

Heparin-induced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to low-molecular weight heparin. In this comprehensive review, the authors highlight heparin-induced thrombocytopenia's risk factors, clinical presentation, pathophysiology, diagnostic principles, and treatment. The authors place special emphasis on the management of patients requiring procedures using cardiopulmonary bypass or interventions in the catheterization laboratory. Clinical vigilance of this disease process is important to ensure its recognition, diagnosis, and treatment. Misdiagnosis of the syndrome, as well as misunderstanding of the disease process, continues to contribute to its morbidity and mortality.

Coagulation disorders and their cutaneous presentations: Pathophysiology

Hypercoagulable states are inherited or acquired predispositions to venous or arterial thromboses that are best understood in the context of the coagulation cascade. Dermatologists can play a critical role in diagnosing and treating patients with hypercoagulable states because cutaneous symptoms may be a presenting manifestation, thereby reducing morbidity and mortality related to these conditions. This review focuses on the epidemiology and pathophysiology of hypercoagulable states, while the accompanying article iterates the basic clinical features, diagnostic testing, and management of patients who have these conditions.

Increased prevalence of heparin-induced thrombocytopenia in patients with Budd-Chiari syndrome: a retrospective analysis

BACKGROUND

Budd-Chiari syndrome (BCS) is a rare, potentially fatal disease characterized by hepatic venous outflow tract obstruction. Heparin-induced thrombocytopenia (HIT) is an immune-mediated complication of heparin therapy, with mortality approaching 10%. The reported prevalence of HIT in adults is 0.2-5.2%. Expert consensus through case reports is the only existing evidence of HIT in BCS. To our knowledge, this is the first study to formalize this anecdotal evidence.

METHODS

A retrospective analysis was carried out of patients presenting at a tertiary liver centre with acute liver failure because of BCS or BCS as the primary indication for liver transplantation between 2000 and 2013. The prevalence of HIT in the study group was compared with the highest reported prevalence in adult medical patients receiving heparin (5.2%). Mortality, length of stay and liver transplantation rates were also studied.

RESULTS

Of 32 BCS patients, 9 (28.1%) developed HIT, significantly higher than the previously reported prevalence of HIT in medical patients (5.2%) (P<0.0001). There was no difference in mortality (P=0.66), length of stay (P=0.58) and liver transplantation rate (P=0.39) between HIT-positive and HIT-negative patients.

CONCLUSION

The prevalence of HIT (28.1%) in our cohort of BCS patients is significantly higher than that in the general population (0.2-5.2%). Although this study was not powered to detect outcome differences, as heparin is the mainstay of acute BCS treatment, this represents a significant risk. We recommend a high index of suspicion for HIT in patients with BCS and thrombocytopenia, an appropriate HIT-testing strategy and consideration of direct thrombin inhibitors.

A case report of sudden thrombocytopenia detected only by in vitro analysis

We experienced an unexpected thrombocytopenia detected only in vitro during radical prostatectomy for a 66-year-old patient. Thrombocytopenia with platelet aggregation was observed in a blood sample obtained using a heparinized syringe (not by ethylene diamine tetra-acetic acid tube). Although we could not exclude platelet agglutination in vivo, no thrombosis or coagulation disorder was observed. We changed the anti-coagulant in the arterial catheter carrier fluid (saline) from heparin to argatroban, and continued with the operation. No embolic complications were observed during the perioperative period. Although pseudothrombocytopenia or heparin-induced thrombocytopenia was highly suspected in the present case, we were not able to confirm which of the two developed. Multi-directional attention and care may be required for perioperative unexpected thrombocytopenia.

Apixaban used for the management of heparin-induced thrombocytopenia in a 72-year-old woman with lung cancer

Heparin‐induced thrombocytopenia (HIT) is a serious adverse reaction to heparin treatment with a high risk of thrombosis. Heparin must be discontinued immediately and replaced with alternative anticoagulants that do not interact with HIT antibodies. In this case, a lung cancer patient, diagnosed with HIT was successfully treated with apixaban.

Flushing and Locking of Venous Catheters: Available Evidence and Evidence Deficit

Flushing and locking of intravenous catheters are thought to be essential in the prevention of occlusion. The clinical sign of an occlusion is catheter malfunction and flushing is strongly recommended to ensure a well-functioning catheter. Therefore fluid dynamics, flushing techniques, and sufficient flushing volumes are important matters in adequate flushing in all catheter types. If a catheter is not in use, it is locked. For years, it has been thought that the catheter has to be filled with an anticoagulant to prevent catheter occlusion. Heparin has played a key role in locking venous catheters. However, the high number of risks associated with heparin forces us to look for alternatives. A long time ago, 0.9% sodium chloride was already introduced as locking solution in peripheral cannulas. More recently, a 0.9% sodium chloride lock has also been investigated in other types of catheters. Thrombolytic agents have also been studied as a locking solution because their antithrombotic effect was suggested as superior to heparin. Other catheter lock solutions focus on the anti-infective properties of the locks such as antibiotics and chelating agents. Still, the most effective locking solution will depend on the catheter type and the patient's condition.

Hypersensitivity reactions to modern antiplatelet and anticoagulant drugs

Anticoagulation and antiplatelet drugs are among the most commonly used medical drugs. In addition to the long-established heparins, hirudins, coumarins and antiplatelet drugs such as acetylsalicylic acid, numerous novel and predominantly synthetic pharmacologic agents have come onto the market in recent years. These new agents act at various sites in coagulation and have significantly broadened treatment options. Whilst immunological hypersensitivity reactions are on the whole rare, they have a considerable impact on patient management when they do occur. The present overview discusses the currently known hypersensitivity reactions to anticoagulant and antiplatelet agents, with particular attention to the newer substance classes including P2Y₁₂ inhibitors, glycoprotein IIb/IIIb receptor antagonists, direct factor Xa inhibitors and direct thrombin inhibitors.