Antithrombin III deficiency as a reflection of dynamic protein metabolism in patients undergoing vascular reconstruction

Venous thromboembolism in viral diseases: A comprehensive literature review

Venous thromboembolism (VTE) is known to be a common respiratory and/or cardiovascular complication in hospitalized patients with viral infections. Numerous studies have proven human immunodeficiency virus infection to be a prothrombotic condition. An elevated VTE risk has been observed in critically ill H1N1 influenza patients. VTE risk is remarkably higher in patients infected with the Hepatitis C virus in contrast to uninfected subjects. The elevation of D-dimer levels supported the association between Chikungunya and the Zika virus and the rise of clinical VTE risk. Varicella-zoster virus is a risk factor for both cellulitis and the consequent invasive bacterial disease which may take part in thrombotic initiation. Eventually, hospitalized patients infected with the coronavirus disease of 2019 (COVID-19), the cause of the ongoing worldwide pandemic, could mainly suffer from an anomalous risk of coagulation activation with enhanced venous thrombosis events and poor quality clinical course. Although the risk of VTE in nonhospitalized COVID-19 patients is not known yet, there are a large number of guidelines and studies on thromboprophylaxis administration for COVID-19 cases. This study aims to take a detailed look at the effect of viral diseases on VTE, the epidemiology of VTE in viral diseases, and the diagnosis and treatment of VTE.

Venous thromboembolism in people living with HIV infection (PWH)

The risk of venous thromboembolism (VTE) and of recurrent VTE remain elevated in people living with HIV compared to controls still with contemporary antiretroviral therapy (ART). The pathophysiology of VTE in HIV is multi factorial and includes an interplay among traditional risk factors, HIV-specific factors, behavioral factors, exposure to ART and other therapies, coinfections, and co-morbidities.

[Perioperative myocardial ischemia : Current aspects and concepts]

In the future an increasing number of older patients with significant comorbidities will have to undergo major surgical procedures. Perioperative cardiovascular events account for many major complications and even fatalities. While perioperative myocardial infarction (PMI) is a generally well-known and recognized complication, the less severe myocardial injury after non-cardiac surgery (MINS) has not gained widespread scientific attention until recently; however, two large observational trials (VISION 1 and VISION 2) have shown a significantly increased mortality after MINS with even subtle increases in troponin T being associated with an increased risk of death. This review summarizes the current knowledge pertaining to PMI and MINS and proposes a diagnostic and therapeutic framework for optimally guiding patients at risk through the perioperative period.

Radionuclide imaging of inflammation in atherosclerotic vascular disease among people living with HIV infection: current practice and future perspective

People living with human immunodeficiency virus (HIV) infection have twice the risk of atherosclerotic vascular disease compared with non-infected individuals. Inflammation plays a critical role in the development and progression of atherosclerotic vascular disease. Therapies targeting inflammation irrespective of serum lipid levels have been shown to be effective in preventing the occurrence of CVD. Radionuclide imaging is a viable method for evaluating arterial inflammation. This evaluation is useful in quantifying CVD risk and for assessing the effectiveness of anti-inflammatory treatment. The most tested radionuclide method for quantifying arterial inflammation among people living with HIV infection has been with F-18 FDG PET/CT. The level of arterial uptake of F-18 FDG correlates with vascular inflammation and with the risk of development and progression of atherosclerotic disease. Several limitations exist to the use of F-18 FDG for PET quantification of arterial inflammation. Many targets expressed on macrophage, a significant player in arterial inflammation, have the potential for use in evaluating arterial inflammation among people living with HIV infection. The review describes the clinical utility of F-18 FDG PET/CT in assessing arterial inflammation as a risk for atherosclerotic disease among people living with HIV infection. It also outlines potential newer probes that may quantify arterial inflammation in the HIV-infected population by targeting different proteins expressed on macrophages.

Issues in the Diagnosis and Management of Hereditary Antithrombin Deficiency

Objective: To review insights gained in the past several years about hereditary antithrombin (AT) deficiency and to outline approaches to the management of patients with AT deficiency in the acute and chronic settings. Data Sources: An extensive literature search of Scopus (January 2008-April 2016) was performed for the terms congenital antithrombin deficiency, inherited antithrombin deficiency, or hereditary antithrombin deficiency. Additional references were identified by reviewing literature citations. Study Selection: All relevant English-language case reports, reviews, clinical studies, meeting abstracts, and book chapters assessing hereditary AT deficiency were included. Data Synthesis: AT deficiency significantly increases the risk of venous thromboembolism (VTE). The risk of VTE is particularly high during pregnancy, the postpartum period, and following major surgery. Effective clinical management includes determination of the appropriate type and duration of antithrombotic therapy (ie, AT replacement for acute situations) while minimizing the risk of bleeding. For persons newly diagnosed with AT deficiency, age, lifestyle, concurrent medical conditions, family history, and personal treatment preferences can be used to individualize patient management. Patients should be informed of the risks associated with hormonal therapy, pregnancy, surgical procedures, and immobility, which further increase the risk of VTE in patients with AT deficiency. Conclusion: AT deficiency poses the highest risk for VTE among the hereditary thrombophilias, often requiring long-term anticoagulation. Undertaking an evaluation for hereditary thrombophilia is controversial; however, a diagnosis of VTE in association with AT deficiency can have management implications. An important treatment option for patients with this disorder in high-risk situations is AT concentrate.

Paroxysmal nocturnal hemoglobinuria: a red clot syndrome

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, nonmalignant disorder of hematopoietic stem cells characterized by hemolysis, diminished hematopoiesis, and thrombophilia. We describe a 65-year-old woman with known PNH and peripheral arterial disease who presented with critical limb ischemia and a nonhealing left foot ulcer. She underwent surgical bypass of a diffusely diseased left superficial femoral artery with autologous reversed saphenous vein graft. Her postoperative course was complicated by wound sepsis and PNH exacerbation with resultant graft thrombosis requiring an above-knee amputation. This case highlights several key concepts relevant to the management of vascular surgery patients with PNH: (1) their predisposition for arterial and venous thrombosis; (2) hypercoagulability despite standard anticoagulation regimens; (3) the role of eculizumab (a monoclonal antibody that inhibits complement activation used to treat PNH) in reducing thrombotic complications and hemolysis; and (4) complications associated with the immunosuppressive effects of eculizumab. We recommend careful monitoring of hemolysis and immunosuppression, aggressive anticoagulation, frequent graft surveillance, and early consultation with hematology.

Vascular graft thrombosis secondary to activated protein C resistance: a case report and literature review

Hypercoagulability is a well-documented and prominent risk factor for venous thromboembolism. The role of thrombophilia in arterial thrombotic events is less well defined. A 52-year-old male patient with multiple atherogenic risk factors was admitted for non-healing pedal ulcer and absent distal pulses. Based on the clinical presentation, Doppler ultrasound and angiography findings, the patient underwent elective in situ bypass arterial reconstruction. The saphenous vein graft was of satisfactory quality and the procedure went routinely. Acute graft thrombosis on postoperative day 0 was recognized immediately and prompted an emergent surgical revision. No technical errors or anatomical/mechanical causes for failed reconstruction were found and the graft was successfully thrombectomized using a Fogarty balloon-catheter. Graft rethrombosis, however, ensued after several hours. Considering the absence of threatening limb ischemia and the idiopathic recurrent thrombosis, raising suspicion of prothrombotic state, conservative treatment was pursued. Postoperative thrombophilia testing proved positive for activated protein C resistance, mandating introduction of chronic oral anticoagulation. Six months later, the operated extremity is viable. Inexplicable vascular graft thrombosis, particularly if early and recurrent, should raise suspicion of underlying thrombophilia. If confirmed by laboratory testing, long-term secondary antithrombotic prophylaxis may be required.

β-blockers and risk of all-cause mortality in non-cardiac surgery

Myocardial ischemia is a frequent complication in patients undergoing non-cardiac surgery and β-blockers may exert a protective effect. The main benefit of β-blockers in perioperative cardiovascular morbidity and mortality is believed to be linked to specific effects on myocardial oxygen supply and demand. β-blockers may exert anti-inflammatory and anti-arrhythmic effects. Randomized clinical trials which evaluated the effects of β-blockers on all-cause mortality in patients undergoing non-cardiac surgery have yielded conflicting results. In 9 trials, 10,544 patients with non-cardiac surgery were randomized to β-blockers (n = 5274) or placebo (n = 5270) and there were a total of 304 deaths. Patients randomized to β-blockers group showed a 19% increased risk of all-cause mortality (odds ratio [OR] 1.19, 95% confidence interval (CI) 0.95-1.50; p = 0.135). However, trials included in the meta-analysis differed in several aspects, and a significant degree of heterogeneity (I 2 = 46.5%) was noted. A recent analysis showed that the surgical risk category had a substantial influence on the overall estimate of the effect of β-blockers. Compared with patients in the intermediate-high-surgical-risk category, those in the high-risk category showed a 73% reduction in the risk of total mortality with β-blockers compared with placebo (OR 0.27, 95% CI 0.10-0.71, p = 0.016). These data suggest that perioperative β-blockers confer a benefit which is mostly limited to patients undergoing high-risk surgery.

[Thrombophilias and peripheral arterial occlusive disease]

Peripheral arterial occlusive disease is a frequent disease due to the classical vascular risk factors such as smoking, diabetes mellitus, dyslipidemia, and hypertension. Despite these risk factors, many thrombophilias (physiological inhibitors defects, Factor V Leiden and 20210A prothrombin gene variant, antiphospholipid antibodies, mild hyperhomocysteinemia 15-30micromol/l) can be evoked in some clinical forms of peripheral arterial occlusive disease. This paper provides a synthesis of the published data about this topic. Screening for these thrombophilias is justified in patients with venous thromboembolic disease, or signs of antiphospholipid syndrome and possibly in different situations such as premature atheroma of lower limbs, chronic ischaemia, evolutive disease despite adapted treatment and revascularisation failures without evident technical explanation. Except for the antiphospholipid syndrome, there is currently no consensus for systematic screening of thrombophilia and treatment in patients with peripheral arterial occlusive disease.

The prevalence of thrombophilia in patients with symptomatic peripheral vascular disease

Background

The aim of this prospective study was to establish the prevalence of thrombophilia and hyperhomocysteinaemia using a comprehensive screen in patients with peripheral vascular disease.

Methods

A total of 150 patients with peripheral vascular disease (with an ankle brachial pressure index of less than 0·8) underwent thrombophilia screening (protein C and protein S, antithrombin, lupus anticoagulant, activated protein C resistance and factor V Leiden and prothrombin mutations). Fasting homocysteine assays were also performed.

Results

A thrombophilia defect was found in 41 patients (27·3 per cent). The commonest was protein S deficiency, found in 17 patients (11·3 per cent). Others included factor V Leiden mutation, found in 10 (6·7 per cent) and protein C deficiency, found in six (4·0 per cent). Lupus anticoagulant and prothrombin mutation were both found in six (4·0 per cent). One patient had an antithrombin deficiency. Only the presence of critical ischaemia was associated with a positive thrombophilia screen on single variable analysis (P = 0·03). Hyperhomocysteinaemia was present in over a third of the study group (37·3 per cent): 45 defined as moderate and 11 as intermediate.

Conclusion

A quarter of patients with peripheral vascular disease had evidence of thrombophilia, and a third had hyperhomocysteinaemia.

Prevalence and Risk of Thrombophilia Defects in Vascular Patients

This paper reviews the available data on the prevalence of thrombophilia defects in patients with peripheral vascular disease (PVD) and attempts to delineate the risk of failure of vascular intervention in these patients. The prevalence of thrombophilia in stable claudicants is 25% and increases to 40% in those requiring revascularisation, compared to only 11% in the control group. The overall prevalence of thrombophilia defects in patients with premature atherosclerosis appears to be between 15 and 30%. The prevalence in the typical cohort of patients with PVD appears to be similar. All these studies have recruited patients with symptoms significant enough to warrant intervention. The overall prevalence of thrombophilia calculated from these trials, therefore, may not be truly indicative of the general vascular population who may not even present primary or secondary healthcare. The risk of thrombotic occlusion following arterial revascularisation in patients with an identified thrombophilia defect appears to be almost three times that of patients with no evidence of a thrombophilia defect. The best management of these patients has not been determined and needs to be evaluated by prospective randomized trials.

The antithrombin III-saving effect of reduced systemic heparinization and heparin-coated circuits

OBJECTIVE

To investigate the perioperative changes of antithrombin III (AT-III) activity using reduced systemic heparinization and the possible role of AT-III in determining a better postoperative outcome.

DESIGN

Prospective randomized study.

SETTING

University hospital.

PARTICIPANTS

Patients undergoing elective coronary revascularization with cardiopulmonary bypass (n = 90).

INTERVENTIONS

Of patients, 30 were treated with heparin-coated circuits and reduced systemic heparinization; 30, with heparin-coated circuits and full systemic heparinization; 30, with conventional circuits and full systemic heparinization.

MEASUREMENTS AND MAIN RESULTS

Heparin-coated circuits with full systemic heparinization did not exert any effect on coagulation parameters. Low systemic heparinization resulted in a significantly (p < 0.01) higher hematocrit value on arrival in the intensive care unit and in significantly higher values of AT-III activity during cardiopulmonary bypass (66 +/- 12% v 57.4 +/- 13% and 59.1 +/- 12% in the full systemic heparinization groups; p < 0.05), on arrival in the intensive care unit (69.7 +/- 13% v 60.7 +/- 13% and 60.8 +/- 11% in the full systemic heparinization groups; p < 0.01), and on the first postoperative day (81.3 +/- 15% v 67.4 +/- 13% and 70.2 +/- 12% in the full systemic heparinization groups; p < 0.01). No differences were observed in the clinical outcome.

CONCLUSION

Reducing systemic heparinization determines an AT-III-saving effect that could be responsible for the decrease in thromboembolic complications already observed by other authors. It induces higher hematocrit levels immediately after the operation, probably reducing the unmeasurable intraoperative blood loss.

Antithrombin levels related to infections and outcome

Antithrombin (AT) was measured in the plasma of 59 trauma patients at Detroit Receiving Hospital from July 1987 through December 1992 to determine how well low AT levels correlated with the outcome and development of later infections. The average lowest AT measured was 74 +/- 14% (SD) (normal = 75 to 120%). The mean lowest AT of the 11 trauma patients who developed sepsis (45 +/- 13%) was significantly lower than that of the 15 who developed an infection without sepsis (66 +/- 12%) (p < 0.001) and of the 33 who did not develop an infection (87 +/- 15%) (p <0.001). No patient with an AT always > or = 70% became septic or died, and no patient with an AT always > or = 90% developed an infection. In the 33 patients who did not develop infections, the mean AT levels rose progressively from 75 +/- 17% during the first 48 hours after admission to 91 +/- 11% during the next 48 hours. In contrast, the mean AT levels in the 26 patients who later developed infections were significantly lower (48 +/- 24%) during the first 48 hours and 60 +/- 16% during the next 48 hours (p < 0.016 and p <0.001). Of 10 patients with an AT < 60% in the first 96 hours, 9 (90%) developed an infection later. Low levels of AT, thus, may be of help in predicting infection, outcome, or both in severely injured patients.

Lower limb ischaemia in primary antiphospholipid syndrome

Primary antiphospholipid syndrome (PAPS) is an autoimmune disorder manifested by recurrent thrombosis in the venous and arterial system. We report a group of seven patients with lower limb ischaemia associated with PAPS. Four were male patients and three were females, with a mean age of 37 years. All had a previous deep vein thrombosis and the majority, five out of seven, had a prior cerebrovascular accident (CVA). Prolonged activated thromboplastin time was demonstrated in all our patients and PAPS was established by positive thromboplastin titration index, circulating anticoagulant index and increased anticardiolipin levels. Symptoms included claudication in three, rest pain in four and gangrene in five patients. Angiography demonstrated thrombosis of various segments of the arterial tree including: aorta, iliac, femoral and popliteal arteries. Two patients were treated conservatively and one by percutaneous transluminal angioplasty (PTA) of the distal aorta. A total of eleven vascular surgical procedures were performed in four patients resulting in early postoperative thrombosis (2h-30 days) in 10 cases. Only one graft remained patent, when full heparinisation (1000 units/h) was used perioperatively. We conclude that PAPS patients are at high risk for graft thrombosis and should only be operated upon on full anticoagulation, starting at operation and proceeding indefinitely.

Greenfield filter instead of heparin as primary treatment for deep venous thrombosis or pulmonary embolism in patients with cancer

BACKGROUND AND METHOD

During the last 5 years, the authors placed Greenfield filters as primary therapy in 41 patients with cancer with deep venous thrombosis (DVT) and/or pulmonary embolism (PE) instead of administering heparin.

RESULTS

There were no operative deaths. Complications included erythema of the incision in one patient, recurrent PE in one patient, and chronic filter prong penetration of the inferior vena caval wall in one patient. Follow-up was complete for 90% (37 of 41) of the patients. Forty-six percent of the patients died of their cancer early in the study. In follow-up, leg swelling improved completely or partially in 74.5% of patients and was unchanged in 22% of patients. The condition of one patient worsened secondary to recurrent DVT. The patients with improved symptoms also had improved functional ability, whereas those whose condition did not change were mostly bedridden, many with end-stage advanced metastatic disease.

CONCLUSIONS

These results indicate that Greenfield filter insertion is safe and effective as primary therapy in patients with cancer with DVT and/or PE.

Review of hypercoagulability syndromes: what the interventionalist needs to know

Although none of these syndromes are very common, they are nevertheless of sufficient prevalence to be identified on occasion in the practice of the busy interventionalist or surgeon. Furthermore, it is anticipated that many more specific hypercoagulability disorders will be identified in the future. Therefore, it is necessary for the nonhematologist practitioner to be aware of their existence and to know when to seek hematology consultation to appropriately evaluate suspected individuals. Several clinical indicators should raise one's index of suspicion. One should be concerned about the patient with a strong family history of recurrent arterial and/or venous thrombosis or a history of previous arterial and/or venous thromboemboli without predisposing factors. Laboratory screening should be initiated for the patient who has had thrombotic events occurring at unusual sites, such as the upper extremity or mesenteric venous circulations, or in young patients presenting with thrombotic events. Patients with chronic arteriosclerotic disease at a young age, with evidence of rapidly progressive atherosclerotic lesions, and especially those who experience early occlusion after uncomplicated surgical or endovascular procedures warrant evaluation. Furthermore, patients manifesting a resistance to therapeutic anticoagulation with conventional agents may also be affected by one of these disorders. Identification of an underlying hypercoagulability disorder will not only influence the decision to proceed with a therapeutic intervention for noncritical arterial insufficiency but will also dictate appropriate pharmacologic management of the hypercoagulable patient to reduce potential thrombotic complications when vascular interventions are performed.