Hypercoagulable syndromes: evaluation and management strategies for acute limb ischemia

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

Role of Anticoagulation in Nonagenarian Patients with Acute Limb Ischemia

BACKGROUND

Preoperative anticoagulant therapy is known to have a positive impact on the prognosis of patients with acute limb ischemia (ALI). However, little is known about its efficacy in elderly patients. We aimed to investigate the potential effect of anticoagulation in nonagenarian patients managed for ALI.

METHODS

Between January 2015 and December 2021, we identified all nonagenarian patients managed for ALI at a single center. Long-term anticoagulation and hemostasis parameters (prothrombin rate, activated partial thromboplastin time [APTT], platelet count) measured on admission were reviewed. The primary end point was mortality at 30-day mortality (D30) in patients with or without long-term anticoagulation therapy. We also studied the effect of these factors on the occurrence of revascularization failure in operated patients (initial failure, ischemic recurrence during hospitalization, necrosis requiring major amputation).

RESULTS

A total of 68 nonagenarian patients were managed for ALI, with a mean age of 93.8 years (from 90-107 years), 76.5% of whom were women. Of these patients, 47 (69%) were managed surgically. Long-term anticoagulation therapy was associated with better survival at D30, both in nonoperated (P < 0.01) and operated (P < 0.05) patients. In operated patients, the absence of long-term anticoagulation therapy was associated with the occurrence of revascularization failure (P < 0.05). In operated patients, survival to D30 and successful revascularization were associated with a longer APTT (P < 0,05). We were able to observe the survival of 4 patients contraindicated for surgery and treated with a single medical therapy (intravenous unfractionated heparin).

CONCLUSIONS

Anticoagulation appears to have an impact on the survival and postoperative prognosis of nonagenarian patients with ALI. In addition, curative anticoagulation therapy may be an alternative treatment when surgery is contraindicated in this frail population.

A retrospective analysis of the investigative practices of acute limb ischaemia presenting with an unknown aetiology

BACKGROUND

Acute limb ischaemia (ALI) is a limb and life-threatening condition with significant morbidity. There are currently no consensus recommendations for the investigative practices to determine the aetiology of ALI presenting without a known aetiology. We undertook a detailed analysis of all investigations performed to identify an underlying precipitant in those with unexplained ALI and formulated a suggested diagnostic algorithm for the evaluation of unexplained ALI.

METHODS

ALI cases presenting to a tertiary referral centre over a 3-year period were reviewed, and known aetiologies, and investigations undertaken to determine the underlying aetiology of unexplained ALI were obtained.

RESULTS

Unexplained ALI was found in 27 of 222 patients (12%), of which 21 (78%) had a cause for ALI established after further investigations. Six patients had no cause identified despite extensive work-up. Most patients with unexplained ALI had a cardioembolic source identified as the underlying cause (62%), and this included atrial fibrillation, infective endocarditis, cardiac myxoma and intra-cardiac thrombus. Other causes of unexplained ALI were detected by computed tomography (CT) imaging and included newly diagnosed significant atherosclerotic disease (19%), embolism from isolated proximal large vessel thrombus (10%) and metastatic malignancy (10%). There were no cases attributed to inherited thrombophilias, myeloproliferative neoplasms or anti-phospholipid syndrome.

CONCLUSION

Among patients with unexplained ALI, the majority had a cardioembolic source highlighting the importance of comprehensive cardiac investigations. A subset of patients had alternative causes identified on CT imaging. These data support the use of a collaborative and integrative diagnostic algorithm in the evaluation of unexplained ALI.

Thrombin Generation Profile in Various Lymphoma Sub-Groups and Its Augmentation by Andexanet Alfa

The prevalence of thrombosis in lymphoma patients is reportedly high and ranges from 3-10%. Vascular malfunction and inflammatory processes further contribute to the thrombotic activation process in these patients. Andexanet alfa (AA) is an antidote for factor Xa inhibitors and its usage has been reported with thrombotic complications. This study was designed to compare the effect of AA on the thrombin generation (TG) potential. Blood samples from 78 patients with confirmed diagnosis of non-Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL) and Chronic lymphocytic leukemia (CLL) were collected from the University of Belgrade Clinic, Serbia. Normal human plasma (NHP) was used for referencing purposes. Individual samples were supplemented with AA at 100 ug/ml. TG studies were carried out using a commercially available fluorogenic substrate method. TG parameters such as peak thrombin (PT), lag time (LT) and area under the curve (AUC) were compiled. Cumulatively, lymphoma patients showed an increase in LT compared to NHP which decreases with AA. The PT and AUC levels were decreased compared to NHP and increases with AA. Upon sub-grouping of lymphoma patients, PT levels for all sub-groups were increased with AA. The AUC values increased for HL and NHL and decreased for CLL with AA. Variations in lag time were noted in all 3 sub-groups. Lymphoma represents a heterogenous group of patients where both the hypercoagulable state and inflammatory responses simultaneously occur. Increased thrombin generation in post AA supplemented samples suggest that the use of this agent may potentially be associated with thrombotic complications.

Surgical thrombectomy versus conservative treatment in cases of acute limb ischemia with COVID-19 pneumonia

COVID-19 infection is a major cause for acute respiratory distress syndrome, multi-organ dysfunction, coagulopathy, and intravascular thrombosis; therefore, it is the main causative factor for acute limb ischemia.

Aim. To compare the treatment outcome of two limb ischemic groups post COVID-19 infection in a single center and detect at least which is better for the patients in the period of COVID-19 pandemic.

Material and methods. Here, in this study, we collect 26 patients and divided them into two groups, G1 (14) patients treated conservatively and G2 (12) patients treated with surgical thrombectomy. Data were analyzed to look for the outcome of groups after 24 hours and 30 days.

Results. The successful rate of conservative treatment was 85,72% in G1, while it was 75% in G2. There were two amputations below the knee joint in each group. Three patients died in both groups.

Conclusion. In conclusion, both conservative treatment and surgical thrombectomy have a comparable successful rate in the selected group of COVID-19 patients.

The Impact of COVID-19 on Vascular Surgery Practice: A Systematic Review

BACKGROUND

COVID-19 is characterized by a pulmonary interstitial compromise which can require intensive care unit (ICU) and mechanical ventilation. Covid patients develop a wide range of pathologies. This study aims to identify the impact of COVID-19 in diseases commonly treated by vascular surgeons.

METHODS

Four conditions were selected: venous thromboembolism (VTE), pulmonary embolism (PE), peripheral arterial disease (PAD), and microangiopathy. A systematic review of the literature using PRISMA guidelines was.

RESULTS

Out of 1195 papers reviewed for conditions in COVID-19 patients relevant to routine vascular surgery practice, 43 papers were included and analyzed. Venous thrombosis was found to be the most common COVID-19 associated pathology with a cumulative incidence of 25% at 7 days and 48% at 14 days. Additionally, D-dimer levels proved to be a good predictor, even in the early stages of the disease with a sensitivity of 85%, specificity of 88.5% and a negative predictive value of 94.7%. Patients in the ICU demonstrated a significantly higher risk of developing VTE, even when receiving pharmacologic thromboprophylaxis. Although evidence of arterial thrombosis was less common (1% to 16.3%), its consequences were typically more serious, including limb loss and death even in young individuals (OR = 25, 95% CI). Finally, microangiopathy has a wide spectrum of clinical presentations from retinal microangiopathy to other more severe manifestations such as myocardial injury, pulmonary compromise and potential multiple organ dysfunction syndrome.

CONCLUSIONS

Although the pathophysiological pathway by which COVID-19 produces thrombosis is not completely clear, the incidence of both arterial and venous thrombosis is increased. D-dimer screening should be done in all COVID-19 patients, as a predictor of thrombotic complications.

Acute limb ischemia in patients with COVID-19 pneumonia

Objective

The aim of our study was to determine the incidence, characteristics, and clinical outcomes of patients with the novel coronavirus (COVID-19) infection who had presented with and been treated for acute limb ischemia (ALI) during the 2020 coronavirus pandemic.

Methods

We performed a single-center, observational cohort study. The data from all patients who had tested positive for COVID-19 and had presented with ALI requiring urgent operative treatment were collected in a prospectively maintained database. For the present series, successful revascularization of the treated arterial segment was defined as the absence of early (<30 days) re-occlusion or major amputation or death within 24 hours. The primary outcomes were successful revascularization, early (≤30 days) and late (≥30 days) survival, postoperative (≤30 days) complications, and limb salvage.

Results

We evaluated the data from 20 patients with ALI who were positive for COVID-19. For the period from January to March, the incidence rate of patients presenting with ALI in 2020 was significantly greater than that for the same months in 2019 (23 of 141 [16.3%] vs 3 of 163 [1.8%]; P < .001)]. Of the 20 included patients, 18 were men (90%) and two were women (10%). Their mean age was 75 ± 9 years (range, 62-95 years). All 20 patients already had a diagnosis of COVID-19 pneumonia. Operative treatment was performed in 17 patients (85%). Revascularization was successful in 12 of the 17 (70.6%). Although successful revascularization was not significantly associated with the postoperative use of intravenous heparin (64.7% vs 83.3%; P = .622), no patient who had received intravenous heparin required reintervention. Of the 20 patients, eight (40%) had died in the hospital. The patients who had died were significantly older (81 ± 10 years vs 71 ± 5 years; P = .008). The use of continuous postoperative systemic heparin infusion was significantly associated with survival (0% vs 57.1%; P = .042).

Conclusions

In our preliminary experience, the incidence of ALI has significantly increased during the COVID-19 pandemic in the Italian Lombardy region. Successful revascularization was lower than expected, which we believed was due to a virus-related hypercoagulable state. The use of prolonged systemic heparin might improve surgical treatment efficacy, limb salvage, and overall survival.

Isquemia arterial aguda de las extremidades: ¿cómo abordarla?

La isquemia arterial aguda de las extremidades se define como la interrupción abrupta del flujo sanguíneo a determinado tejido, lo cual afecta la integridad, la viabilidad de la extremidad, o ambas. Las causas son múltiples y pueden resumirse en dos procesos fisiopatológicos, trombóticos o embólicos, con lo que se puede establecer el pronóstico y el tratamiento según su causa. El cuadro sindrómico es variable, y típicamente, se identifica con las cinco “P” de Pratt (pain, pallor, pulselessness, paralysis and paresthesia); se cuenta con múltiples ayudas diagnósticas, pero la arteriografía sigue siendo el método estándar para el diagnóstico. Con el advenimiento de los avances tecnológicos y los procedimientos vasculares, el salvamento de las extremidades ha venido en aumento y ha disminuido la extensión de las amputaciones, lo cual conlleva una mayor tasa de rehabilitación y de reincorporación a la vida social.

Combined presence of coagulation factor XIII V34L and plasminogen activator inhibitor 1 4G/5G gene polymorphisms significantly contribute to recurrent pregnancy loss in Serbian population

Background

Recurrent pregnancy loss (RPL) is a heterogeneous condition affecting up to 5% of women of reproductive age. Inherited thrombophilia have been postulated as one of the causes of RPL. Here we examined the prevalence of nine thrombophilic gene polymorphisms among women with history of recurrent miscarriages and fertile controls.

Methods

The study included 70 women with history of at least three early pregnancy losses and 31 fertile controls with no miscarriages. We investigated mutations in genes responsible for clotting and fibrinolysis, including factor V (FV) Leiden, FV H1299R, factor II (FII) G20210A, methylene tetrahydrofolate reductase (MTHFR) C677T and A1298C, factor XIII (FXIII) V34L, plasminogen activator inhibitor-1 (PAI-1) 4G/5G and endothelial protein C receptor (EPCR) H1 and H3 haplotypes using reverse polymerase chain reaction ViennaLab cardiovascular disease StrippAssays.

Results

Our results showed no significant increase in prevalence of tested polymorphisms in women with RPL. However, relative risk for PRL among women heterozygous for FXIII V34L was 2.81 times increased (OR 2.81, 95% CI 1.15-6.87, P=0.023). Haplotype analysis showed that combined presence of high-risk genotypes for FXIII and PAI-1 significantly increases risk for RPL (OR 13.98, CI 95% 1.11-17.46, P=0.044).

Conclusions

This is the first study in Serbian population that investigated prevalence of FVR2, A1298C, FXIII V34L and EPCR gene variants. Compound heterozygosity for FXIII V34L and PAI-1 4G is significant risk factor for recurrent miscarriage. Our results should be viewed in context of small case-control study, so further large prospective studies are need for confirmation of our findings.

[Occurrence of Venous Thromboembolism in Patients with Lung Cancer and Its Anticoagulant Therapy]

目前，肺癌的发病率和死亡率在全世界范围内居首位。静脉血栓栓塞症（venous thromboembolism, VTE）是一种公认的肺癌并发症，也是肺癌患者的主要死因之一。癌症自身因素、患者自身因素以及治疗相关因素都是导致肺癌患者发生VTE的主要原因。肿瘤细胞可产生组织因子（tissue factor, TF）、癌性促凝物质（cancer procoagulant, CP）、炎症因子和细胞因子，从而直接激活凝血；其中TF过度表达是肿瘤患者血栓形成的主要机制之一。2016年美国胸外科医师协会（American College of Chest Physicians, ACCP）发布的第10版肿瘤患者VTE防治指南（AT-10）指出，抗凝治疗是肺癌患者合并VTE的基本治疗措施；其中低分子肝素（low molecular-weight-heparin, LWMH）被认为是首选的抗凝药物，但要注意出血风险。

The hypercoagulable states in anaesthesia and critical care

Hypercoagulable disorders are now diagnosed more frequently than before. These patients are, usually, managed with multiple anticoagulant and antiplatelet medications. Left unmonitored and unevaluated, there can be disastrous haemorrhagic or thrombotic complications. Appropriate perioperative and anaesthetic management of these patients will invite an aetiological diagnosis, severity analysis and the on-going treatment review. Different assays, thromboelastography and molecular cytogenetics have helped to diagnose these conditions precisely and thus guide the long-term management. Besides this, there are varieties of clinical conditions that will predispose to the hypercoagulability. These need to be defined and classified in order to offer a suitable therapeutic option. Pregnancy is one such important condition and can have more than one responsible factor favouring hypercoagulability. With such diverse kinds of disorders, it would be essential to note the anaesthetic implications, to avoid adverse perioperative outcomes. Available evidence based guidelines will help to make the therapeutic approach more precise. Selection of the appropriate technique of anaesthesia, offering the appropriate anticoagulation bridging as necessary and defining an appropriate interval and time for the intervention will help to minimise the complications.

Cancer-associated thrombosis

Thrombosis is a common complication in patients with cancer and it is estimated that about 20% of patients with cancer experience venous thromboembolism (VTE). This complication is associated with high rate of morbidity and mortality and is sometimes the first manifestation of an occult cancer. The risk profiles and markers involved in cancerassociated thrombosis share similarities with inflammation-induced atherosclerosis and thrombosis. The type of cancer, chemotherapy, surgery, central venous catheters, pre-chemotherapy platelet and leukocyte count are associated with high risk of VTE in cancer patients. Landmark studies demonstrated that effective prophylaxis and treatment of VTE reduced morbidity and increased survival. Low-molecular-weight heparin (LMWH) is preferred as an effective and safe means for prophylaxis and treatment of VTE. It has largely replaced unfractionated heparin and vitamin K antagonists. The advantages of LMWH include increased survival and quality of life, decreased rate of VTE, low incidence of thrombocytopenia. New guidelines for prophylaxis and treatment are now available and prophylaxis is recommended in hospitalized cancer patients and patients undergoing major surgery. Treatment with LMWH should be considered as the first line of therapy for established VTE and to prevent recurrent thrombosis in patients with cancer.

Cancer and thrombosis: mechanisms and treatment

Standard venous thromboembolic event (VTE) treatment practices including the use of intravenous unfractionated heparin (UFH) for initial anticoagulation, oral warfarin for chronic anticoagulation, and the prescription of only 3 to 6 months total therapy may not be optimal in the setting of active cancer and ongoing anti-cancer therapy. Challenges of VTE management in cancer patients include heparin resistance due to excess circulating acute-phase proteins, increased recurrence rates during and following standard-intensity warfarin therapy, limited venous access to support therapeutic monitoring, and anticoagulation intensity-independent increased bleeding rates during anticoagulation. Bleeding during anticoagulation is of particular concern in the treatment of cancer patients with disease- or chemotherapy-related thrombocytopenia, central nervous system involvement, or recent invasive procedures. Low-molecular weight heparins (LMWH) have been shown to be at least as effective and safe for initial anticoagulation compared with UFH in persons with acute VTE and have gained popularity in the setting of VTE in cancer. LMWHs have the advantage of less non-specific protein binding, subcutaneous weight-based dosing without the need for monitoring in most cases, and probably less heparin-induced thrombocytopenia. Recent trials have demonstrated efficacy superiority of select LMWHs in place of oral warfarin for long-term anticoagulation in the cancer patient. The potential for anti-tumor effects and a survival advantage associated with select classes of anticoagulant agents is actively being investigated.

Hypercoagulable state testing and malignancy screening following venous thromboembolic events

Mounting interest in hypercoagulability, increased availability of hypercoagulable state test 'panels' and enhanced ability to identify abnormalities in tested patients have prompted widespread testing. Testing for acquired and inherited hypercoagulable states uncovers an abnormality in over 50% of patients presenting with an initial venous thromboembolic event (VTE) but may have minimal actual impact on management in most of these patients. Such laboratory screening should be reserved for patients in whom the results of individual tests will significantly impact the choice of anticoagulant agent, intensity of anticoagulant therapy, therapeutic monitoring, family screening, family planning, prognosis determination, and most of all duration of therapy. Testing 'just to know' is neither cost-effective nor clinically appropriate. The most important testing in patients following acute VTE may be age- and gender-specific cancer screening. Cancer screening following VTE seems most prudent in older individuals and in those with idiopathic VTE and no laboratory evidence for an inherited hypercoagulable state. Cancer screening should focus on identification of treatable cancers and those where diagnosis in an early stage favorably impacts patient survival. Extensive searches for occult malignancy employing whole-body computed tomography and serum tumor markers may identify more cancers but without affecting patient outcome. We advocate that physicians should focus their attention more on VTE prophylaxis and proper treatment and less on costly and, at times, invasive testing of questionable value.