Lead Extraction-Indications, Procedure, and Future Directions.

Cardiac implantable electronic device (CIED) implantation has steadily increased in the United States owing to increased life expectancy, better access to health care, and the adoption of updated guidelines. Transvenous lead extraction (TLE) is an invasive technique for the removal of CIED devices, and the most common indications include device infections, lead failures, and venous occlusion. Although in-hospital and procedure-related deaths for patients undergoing TLE are low, the long-term mortality remains high with 10-year survival reported close to 50% after TLE. This is likely demonstrative of the increased burden of comorbidities with aging. There are guidelines provided by various professional societies, including the Heart Rhythm Society, regarding indications for lead extraction and management of these patients. In this paper, we will review the indications for CIED extraction, procedural considerations, and management of these patients based upon the latest guidelines.

Recurrent Spontaneous Coronary Artery Dissection: A Case of Triple Trouble.

SCAD (Spontaneous Coronary Artery Dissection) is a rare disorder which rarely recurs. It is increasingly diagnosed as a cause for acute coronary syndrome (ACS) with limited insight into its pathophysiology and treatment. Lack of randomized trials and consensus guidelines make this a unique and challenging disease to manage. We describe a complex case of recurrent idiopathic SCAD with prior history of NSTE-ACS (Non-ST elevation Acute Coronary Syndrome) and discuss its management based on current clinical practices.

The safety profile of COVID-19 vaccinations in the United States.

BACKGROUND/AIM: Pfizer-BioNTech, Moderna, and Johnson & Johnson's Janssen are the 3 COVID-19 vaccines authorized for emergency use in the United States. This study aims to analyze and compare adverse events following immunization associated with these COVID-19 vaccines based on Vaccine Adverse Effect Reporting System data. METHODS: We utilized Vaccine Adverse Effect Reporting System data from January 1, 2021 to April 30, 2021 to analyze and characterize adverse effects postvaccination with these authorized COVID-19 vaccines in the US population. RESULTS: A total of 141,208 individuals suffered at least one adverse events following immunization following 239.97 million doses of COVID-19 vaccination. The frequency of side effects was 0.04%, 0.06%, and 0.35% following administration of Pfizer-BioNTech, Moderna, and Johnson & Johnson's Janssen vaccines, respectively. Most of the patients had mild systemic side effects, the most common being headache (0.01%) and fever (0.01%). The frequency of serious side effects including anaphylaxis (0.0003%) and death (0.002%) was extremely low. CONCLUSIONS: The three COVID 19 vaccines have a wide safety profile with only minor and self-limiting adverse effects. However, continued monitoring and surveillance is required to review any unexpected serious adverse effects.

Thromboprophylaxis for deep vein thrombosis and pulmonary embolism after total joint arthroplasty in a low incidence population.

Postoperative venous thromboembolism is one of the most serious complications following total joint arthroplasty. Pharmacological and mechanical prophylaxis methods are used to reduce the risk of postoperative symptomatic deep vein thrombosis and pulmonary embolism. Use of pharmacological prophylaxis requires a fine balance between the efficacy of the drug in preventing deep vein thrombosis and the adverse effects associated with the use of these drugs. In regions with a low prevalence of deep vein thrombosis such as Korea, there might be a question whether the benefits of using pharmacological prophylaxis outweigh the risks involved. The current article reviews the need for thromboprophylaxis, guidelines, problems with the guidelines, pharmacological prophylaxis use, and the current scenario of deep vein thrombosis, and discusses whether the use of pharmacological prophylaxis should be mandatory in low incidence populations.

Is routine chemoprophylaxis necessary for prevention of venous thromboembolism following knee arthroplasty in a low incidence population?

BACKGROUND: Standard thromboprophylaxis guidelines have not been applied universally in regions with low incidence of deep-vein thrombosis (DVT) considering risks of chemoprophylaxis and low incidence itself. We evaluated the prevalence of DVT, efficacy and safety of chemoprophylaxis, and necessity of pharmacological prevention in a low DVT incidence population. METHODS: One hundred and forty-eight patients undergoing unilateral total knee arthroplasty (TKA) were prospectively randomized to receive either a placebo or 2.5 mg of fondaparinux once daily for 5 days. Doppler ultrasonography was performed preoperatively and 7 days after surgery. The primary efficacy outcome was prevalence of DVT up to day 7. Secondary efficacy outcome was prevalence of symptomatic venous thromboembolism (VTE) up to day 90. Primary and secondary safety outcomes were incidence of major and minor bleeding, respectively. RESULTS: The prevalence of total DVT was 25.7 % in placebo group and 6.8 % in fondaparinux group (p = 0.002) and the prevalence of proximal DVT was lower in both groups with no statistical difference. There was no symptomatic VTE in either group up to day 90. Although no major bleeding was developed, fondaparinux group had a significant increase of minor bleeding events (p < 0.001). CONCLUSIONS: There remains low incidence of VTE following TKA in East Asians even without chemoprophylaxis. Although short-term fondaparinux protocol could reduce the incidence of overall DVT, its routine use seems debatable due to extremely rare proximal DVT and symptomatic PE and drug-related bleeding complication. However, modified and selective use of chemoprophylaxis would be considerable in high risk patients.

Less blood loss under concomitant administration of tranexamic acid and indirect factor Xa inhibitor following total knee arthroplasty: a prospective randomized controlled trial.

PURPOSE: The objective of this prospective randomized controlled trial was to assess the efficacy and safety of simultaneous application of tranexamic acid and indirect factor Xa inhibitor following total knee arthroplasty (TKA). METHODS: Seventy-two primary osteoarthritis patients undergoing unilateral TKA using fondaparinux as a basic thromboprophylaxis were randomized to receive either placebo (36 patients) or tranexamic acid (36 patients). Prophylaxis against venous thromboembolism in all patients was administered with subcutaneous doses of 2.5 mg fondaparinux for 5 days post-operatively. Post-operative retransfusion volume, allogenic transfusion volumes and drain amount were recorded for each patient. Level of haemoglobin, prothrombin time, activated partial thromboplastin time and D-dimer were also assessed. Doppler ultrasonography was performed preoperatively and 7 days after surgery. RESULTS: The rate of transfusion was lower in the tranexamic acid group than in the placebo group (p = 0.007). The drained blood volume during the initial 24 h and until drain removal was smaller in the tranexamic acid group than in the placebo group (p < 0.001). However, the haematologic laboratory results did not show any significant differences between the two groups. The prevalence of deep-vein thrombosis (DVT) was 4 (11.1 %) in the placebo group and 3 (8.3 %) in the tranexamic acid group (p = n.s.). There was no proximal DVT and no symptomatic pulmonary embolism in either group. CONCLUSION: The use of tranexamic acid could reduce acute blood loss significantly without any adverse effect resulted from drug interaction with concomitant use of indirect factor Xa inhibitor following TKA. Therefore, simple combination of these drugs can be recommended to reduce post-operative blood loss as well as to reduce DVT following TKA.

Recent Korean perspective of deep vein thrombosis after total knee arthroplasty.

This prospective study was performed on 311 consecutive knees in 227 patients for total knee arthroplasty. The aim was to assess the recent incidence of deep vein thrombosis (DVT) after total knee arthroplasty without chemoprophylaxis in Koreans, the efficacy of plasma d-dimer levels as a screening test, and the associated risk factors. Deep vein thrombosis was found in 79 knees (26.60%). There were 9 cases (3.03%) of proximal DVT, 70 cases (23.57%) of distal DVT, and no symptomatic pulmonary embolism. Although this cohort had limited number of patients by a single surgeon, there is still low incidence of proximal DVT in Koreans with rare pulmonary embolism occurrence compared with those of the Western. High postoperative d-dimer levels were correlative, but no appropriate cutoff value was found. Obesity was a significant associated risk factor.

MHC class II tetramers containing influenza hemagglutinin and EBV EBNA1 epitopes detect reliably specific CD4(+) T cells in healthy volunteers.

Tracking antigen specific T cells with major histocompatibility complex (MHC) tetramers has provided us with insights into the dynamics of the adaptive immune system and holds great promise to aid in patient management and drug and vaccine development. Progress has been made primarily using MHC class I tetramers to monitor CD8(+) T cells, whereas corresponding efforts to stain CD4(+) T cells with class II tetramers have not been as successful. Two major reasons have been proposed for this lack of progress: (1). The frequency of antigen-specific CD4(+) T cells is lower than the frequency of CD8(+) T cells and (2). some, but not all, antigen- specific CD4(+) T cells can bind tetramer because of low functional avidity. In this study, we asked if CD4(+) T cells specific for common human viruses (e.g., influenza and Epstein-Barr) can be detected in healthy individuals previously exposed to them. We were able to clearly detect specific CD4(+) T cells in all donors after in vitro expansion of peripheral blood mononuclear cells. Furthermore, we observe a clear separation of tetramer negative and tetramer positive CD4(+) T cells in most samples similar to patterns commonly seen with class I tetramers. The data indicate that MHC class II tetramers can be used reliably for the identification of CD4(+) T cells specific for ubiquitous infectious agents in normal donors.