Therapeutic efficacy of heparin and direct factor Xa inhibitors in cancer-associated cryptogenic ischemic stroke with venous thromboembolism

Cancer-Associated Stroke: Thrombosis Mechanism, Diagnosis, Outcome, and Therapeutic Strategies

Cancer can induce hypercoagulability, which may lead to stroke. This occurs when tumor cells activate platelets as part of their growth and metastasis. Tumor cells activate platelets by generating thrombin and expressing tissue factor, resulting in tumor cell-induced platelet aggregation. Histopathological studies of thrombi obtained during endovascular thrombectomy in patients with acute stroke and active cancer have shown a high proportion of platelets and thrombin. This underscores the crucial roles of platelets and thrombin in cancer-associated thrombosis. Cancer-associated stroke typically occurs in patients with active cancer and is characterized by distinctive features. These features include multiple infarctions across multiple vascular territories, markedly elevated blood D-dimer levels, and metastasis. The presence of cardiac vegetations on echocardiography is a robust indicator of cancer-associated stroke. Suspicion of cancer-associated stroke during endovascular thrombectomy arises when white thrombi are detected, particularly in patients with active cancer. Cancer-associated stroke is almost certain when histopathological examination of thrombi shows a very high platelet and a very low erythrocyte composition. Patients with cancer-associated stroke have high risks of mortality and recurrent stroke. However, limited data are available on the optimal treatment regimen for stroke prevention in these patients. Thrombosis mechanism in cancer is well understood, and distinct therapeutic targets involving thrombin and platelets have been identified. Therefore, direct thrombin inhibitors and/or antiplatelet agents may effectively prevent stroke recurrence. Additionally, this strategy has potential benefits in cancer treatment as accumulating evidence suggests that aspirin use reduces cancer progression, metastasis, and cancer-related mortality. However, clinical trials are necessary to assess the efficacy of this strategy involving the use of direct thrombin inhibitors and/or antiplatelet therapies.

Development of an algorithm for identifying paraneoplastic ischemic stroke in association with lung, pancreatic, and colorectal cancer

Background

Paraneoplastic ischemic stroke has a poor prognosis. We have recently reported an algorithm based on the number of ischemic territories, C-reactive protein (CRP), lactate dehydrogenase (LDH), and granulocytosis to predict the underlying active cancer in a case-control setting. However, co-occurrence of cancer and stroke might also be merely incidental.

Objective

To detect cancer-associated ischemic stroke in a large, unselected cohort of consecutive stroke patients by detailed analysis of ischemic stroke associated with specific cancer subtypes and comparison to patients with bacterial endocarditis.

Methods

Retrospective single-center cohort study of consecutive 1612 ischemic strokes with magnetic resonance imaging, CRP, LDH, and relative granulocytosis data was performed, including identification of active cancers, history of now inactive cancers, and the diagnosis of endocarditis. The previously developed algorithm to detect paraneoplastic cancer was applied. Tumor types associated with paraneoplastic stroke were used to optimize the diagnostic algorithm.

Results

Ischemic strokes associated with active cancer, but also endocarditis, were associated with more ischemic territories as well as higher CRP and LDH levels. Our previous algorithm identified active cancer-associated strokes with a specificity of 83% and sensitivity of 52%. Ischemic strokes associated with lung, pancreatic, and colorectal (LPC) cancers but not with breast and prostate cancers showed more frequent and prominent characteristics of paraneoplastic stroke. A multiple logistic regression model optimized to identify LPC cancers detected active cancer with a sensitivity of 77.8% and specificity of 81.4%. The positive predictive value (PPV) for all active cancers was 13.1%.

Conclusion

Standard clinical examinations can be employed to identify suspect paraneoplastic stroke with an adequate sensitivity, specificity, and PPV when it is considered that the association of ischemic stroke with breast and prostate cancers in the stroke-prone elderly population might be largely incidental.

Cancer-Associated Stroke and Acute Endovascular Reperfusion Therapy

Since stroke is often associated with cancer, acute stroke patients with cancer undergoing endovascular therapy (EVT) are not uncommon. Reportedly, the proportion of such cases is approximately 6%-7% of all stroke EVT cases. Ischemic stroke in patients with active cancer (cancer-associated stroke) includes not only strokes caused by cancer-related hypercoagulability but also coincident strokes due to common etiologies, strokes associated with tumor emboli, direct tumor invasion of blood vessels, and strokes associated with cancer therapy. Stroke caused by cancer-related hypercoagulability itself encompasses various entities, including paradoxical embolism, stroke due to nonbacterial thrombotic endocarditis, and in situ arterial occlusion due to disseminated intravascular coagulation or thrombotic microangiopathy. Thus, diverse mechanisms contribute to cancer-associated stroke, emphasizing the need to consider individualized treatment strategies for acute cases involving large vessel occlusion. Observational studies have shown that EVT for cancer-associated stroke results in poorer clinical outcomes, but with comparable rates of successful reperfusion and symptomatic intracranial hemorrhage when compared with stroke patients without cancer. This suggests that denying patients EVT solely on the basis of comorbid active cancer is inappropriate, and decision-making should be shared with the patients and their families, preferably through a multidisciplinary team approach. Thrombi retrieved from patients with stroke caused by cancer-related hypercoagulability have unique characteristics, being predominantly platelet rich and difficult to retrieve. Preprocedural imaging and serum biomarkers, including the hyperdense vessel sign on non-contrast CT, susceptibility vessel sign on T2* or susceptibility-weighted MRI, three-territory sign on MRI, and D-dimer levels, are valuable in evaluating the stroke subtype and thrombus features. Thrombectomy techniques, such as contact aspiration and stent retriever monotherapy, have shown varying degrees of effectiveness for stroke caused by cancer-related hypercoagulability, warranting further study. After reperfusion therapy, appropriate treatment for the prevention of stroke recurrence should be initiated, considering the specific stroke subtypes. In conclusion, cancer-associated stroke encompasses diverse subtypes, and thrombi associated with stroke caused by cancer-related hypercoagulability present various challenges for thrombectomy. Individualized treatment approaches based on underlying mechanisms are essential for improving outcomes in acute stroke patients with active cancer. Optimization of preprocedural diagnosis, EVT techniques, and secondary prevention of stroke caused by cancer-related hypercoagulability will lead to better management of these patients and enhance their quality of life.

Cancer-related cryptogenic stroke involving the bilateral anterior and the posterior circulations: Diagnostic value of clinical and imaging characteristics

Objectives

This study analyzed the clinical and imaging characteristics of patients with cancer-related cryptogenic stroke (CCS) involving the bilateral anterior and the posterior circulations (three circulations) and evaluate the diagnostic value of clinical and imaging features for patients with cryptogenic stroke involving three circulations (CST).

Methods

Of the 12,580 patients with acute ischemic stroke, 148 patients with CST from May 2017 to November 2021 were divided into the cancer group (n = 81) and the non-cancer group (n = 67). Cardiovascular risk factors, diffusion-weighted imaging patterns of cryptogenic stroke, blood routine, coagulation routine, and biochemical routine were compared between the two groups. Multivariable logistic regression and receiver operating characteristic (ROC) curve analysis were used to determine associations between the two groups.

Results

Compared with the non-cancer group, the cancer group exhibited higher D-dimer levels (P < 0.001), fibrin degradation product (FDP, P < 0.001), international normalized ratio (INR, P = 0.014), neutrophil to lymphocyte ratio (NLR, P < 0.001), platelets to lymphocyte ratio (PLR, P = 0.001), activated partial thromboplastin time (APTT, P = 0.039), more frequent multiple lesions in three circulations (P < 0.001) and lower lymphocytes (P < 0.001), red blood cells (P < 0.001), and thrombin time (TT, P = 0.034). Furthermore, D-dimer [area under the curve (AUC) = 0.915, P < 0.001)], FDP (AUC = 0.923, P < 0.001), INR (AUC = 0.617, P = 0.014), NLR (AUC = 0.700, P < 0.001), PLR (AUC = 0.658, P = 0.001), and multiple lesions in three circulations (AUC = 0.786, P < 0.001) had potential diagnostic value in cryptogenic stroke. When combining these 6 parameters, the predictive power was improved (AUC = 0.949, P < 0.001).

Conclusion

Cryptogenic stroke involving three circulations with cancer has unique clinical features, and these potential diagnostic indicators could help patients identify CCS earlier.

Cancer-related stroke: Exploring personalized therapy strategies

BACKGROUND

Cancer and ischemic stroke are two common diseases that threaten human health and have become the main causes of death in the world. It is estimated that one-in-ten patients with ischemic stroke have concomitant cancer, and this incidence is expected to increase as improvements in medical technology extends the life expectancy of cancer patients.

DISCUSSION

Cancer-related stroke (CRS) refers to unexplained ischemic stroke in patients with active cancer that cannot be explained by current stroke mechanisms. Available evidence suggests that CRS accounts for 5-10% of embolic stroke of undetermined source (ESUS). Although the incidence of CRS is gradually increasing, its underlying pathogenesis remains unclear. Also, there is no consensus on acute treatment and secondary prevention of stroke.

CONCLUSION

In this review, we retrospectively analyzed the incidence, mechanisms of CRS, its potential as a new stroke subtype, options for acute treatment, secondary prevention strategies, and disease progression, with the aim of attempting to explore personalized therapy strategies.

Pharmacokinetic, Hemostatic, and Anticancer Properties of a Low-Anticoagulant Bovine Heparin

Heparin is a centennial anticoagulant drug broadly employed for treatment and prophylaxis of thromboembolic conditions. Although unfractionated heparin (UFH) has already been shown to have remarkable pharmacological potential for treating a variety of diseases unrelated with thromboembolism, including cancer, atherosclerosis, inflammation, and virus infections, its high anticoagulant potency makes the doses necessary to exert non-hemostatic effects unsafe due to an elevated bleeding risk. Our group recently developed a new low-anticoagulant bovine heparin (LABH) bearing the same disaccharide building blocks of the UFH gold standard sourced from porcine mucosa (HPI) but with anticoagulant potency approximately 85% lower (approximately 25 and 180 Heparin International Units [IU]/mg). In the present work, we investigated the pharmacokinetics profile, bleeding potential, and anticancer properties of LABH administered subcutaneous into mice. LABH showed pharmacokinetics profile similar to HPI but different from the low-molecular weight heparin (LMWH) enoxaparin and diminished bleeding potential, even at high doses. Subcutaneous treatment with LABH delays the early progression of Lewis lung carcinoma, improves survival, and brings beneficial health outcomes to the mice, without the advent of adverse effects (hemorrhage/mortality) seen in the animals treated with HPI. These results demonstrate that LABH is a promising candidate for prospecting new therapeutic uses for UFH.

Pharmacokinetic, hemostatic and anticancer properties of a low-anticoagulant bovine heparin

Heparin is a centennial anticoagulant drug broadly employed for treatment and prophylaxis of thromboembolic conditions. Although unfractionated heparin (UFH) has already been shown to have remarkable pharmacological potential for treating a variety of diseases unrelated with thromboembolism, including cancer, atherosclerosis, inflammation, and virus infections, its high anticoagulant potency makes the doses necessary to exert non-hemostatic effects unsafe due to an elevated bleeding risk. Our group recently developed a new low-anticoagulant bovine heparin (LABH) bearing the same disaccharide building blocks of the UFH gold standard sourced from porcine mucosa (HPI) but with anticoagulant potency approximately 85% lower (approximately 25 and 180 Heparin International Units [IU]/mg). In the present work, we investigated the pharmacokinetics profile, bleeding potential, and anticancer properties of LABH administered subcutaneous into mice. LABH showed pharmacokinetics profile similar to HPI but different from the low-molecular weight heparin (LMWH) enoxaparin and diminished bleeding potential, even at high doses. Subcutaneous treatment with LABH delays the early progression of Lewis lung carcinoma, improves survival, and brings beneficial health outcomes to the mice, without the advent of adverse effects (hemorrhage/mortality) seen in the animals treated with HPI. These results demonstrate that LABH is a promising candidate for prospecting new therapeutic uses for UFH.

A Review of Potential Mechanisms of Cryptogenic Stroke and a Recommended Approach to Diagnosis

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