Outcome of Stroke Patients with Cancer and Nonbacterial Thrombotic Endocarditis

Cancer patients and ischemic stroke

Patients with cancer have an increased risk of ischemic stroke compared to the general population. Additionally, these patients have a worse prognosis compared to stroke patients without cancer. Activation of coagulation appears to play a key role in the pathophysiology of ischemic stroke in patients with cancer. However, the underlying mechanisms remain unknown. Moreover, we do not have a way to identify cancer patients with a high risk of stroke and cannot develop prevention strategies. Therefore, there is an urgent need for neurologists and oncologists to develop screening and prevention strategies for stroke in patients with cancer. In this review, we summarize the characteristics of cancer patients at a high risk of stroke, the predictors for the development of stroke and survival in cancer patients, and possible treatments.

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.

Ischemic Stroke in Cancer: Mechanisms, Biomarkers, and Implications for Treatment

Ischemic stroke is an important cause of morbidity and mortality in cancer patients. The underlying mechanisms linking cancer and stroke are not completely understood. Long-standing and more recent evidence suggests that cancer-associated prothrombotic states, along with treatment-related vascular toxicity, such as with chemotherapy and immunotherapy, contribute to an increased risk of ischemic stroke in cancer patients. Novel biomarkers, including coagulation, platelet and endothelial markers, cell-free DNA, and extracellular vesicles are being investigated for their potential to improve risk stratification and patient selection for clinical trials and to help guide personalized antithrombotic strategies. Treatment of cancer-related stroke poses unique challenges, including the need to balance the risk of recurrent stroke and other thromboembolic events with that of bleeding associated with antithrombotic therapy. In addition, how and when to restart cancer treatment after stroke remains unclear. In this review, we summarize current knowledge on the mechanisms underlying ischemic stroke in cancer, propose an etiological classification system unique to cancer-related stroke to help guide patient characterization, provide an overview of promising biomarkers and their clinical utility, and discuss the current state of evidence-based management strategies for cancer-related stroke. Ultimately, a personalized approach to stroke prevention and treatment is required in cancer patients, considering both the underlying cancer biology and the individual patient's risk profile.

Coagulation Factor Expression and Composition of Arterial Thrombi in Cancer-Associated Stroke

BACKGROUND

Cancer is associated with an increased risk of stroke. Tumor cells activate platelets, induce a coagulation cascade, and generate thrombin. The composition of thrombi may reflect the mechanism of thrombosis, aiding the determination of the treatment strategy. Here, we investigated the composition and expression of coagulation factors in the thrombi of patients with cancer-associated stroke.

METHODS

Patients with stroke who underwent endovascular thrombectomy between September 2014 and June 2020 and whose cerebral thrombi were obtained were divided into those with cancer-associated stroke (cancer group) and propensity score-matched patients without cancer (control group), using 1:1 matching based on age and sex. Immunohistochemistry was performed of the thrombi, and the composition and expression of coagulation factors were compared between groups.

RESULTS

Among the 320 patients who underwent endovascular thrombectomy and who had thrombi obtained, this study included 23 patients with cancer and 23 matched controls. In both groups, the median age was 65 years, and 12 patients (52.2%) were men. Platelet composition was significantly higher in the cancer group than in the control group (median [interquartile range], 51.3% [28.0%-61.4%] versus 9.5% [4.8%-14.0%]; P<0.001). Among coagulation factors, thrombin (26.2% [16.2%-52.7%] versus 4.5% [1.3%-7.2%]; P<0.001) and tissue factors (0.60% [0.34%-2.06%] versus 0.37% [0.22%-0.60%]; P=0.024) were higher and factor X was lower (1.25% [0.39%-3.60%] versus 2.33% [1.67%-4.48%]; P=0.034) in the cancer group. There was a positive correlation between thrombin and platelets in the cancer group (r=0.666; P=0.001) but not in the control group (r=-0.167; P=0.627).

CONCLUSIONS

Cerebral thrombi in patients with cancer-associated stroke showed higher proportions of platelets, thrombin, and tissue factors, suggesting their key roles in arterial thrombosis in cancer and providing a therapeutic perspective for preventing stroke in patients with cancer-associated stroke.

Quadrivalvular nonbacterial thrombotic endocarditis in a patient with clear cell cervical cancer

Nonbacterial thrombotic endocarditis (NBTE) is a rare finding, which is mostly associated with malignant diseases leading to hypercoagulability. We report the case of a severe quadruple valve nonbacterial thrombotic endocarditis in a patient with clear cell cervical cancer.

Patent foramen ovale and risks of recurrence in stroke of determined etiology

OBJECTIVE

Patent foramen ovale (PFO) is often found in stroke patients with determined etiologies. PFO may be the actual cause of stroke in some of them. We determined whether the risk of recurrent ischemic stroke differs with PFO status in stroke patients with determined etiologies.

METHODS

This study included consecutive patients with stroke of determined etiology who underwent transesophageal echocardiography. We compared the rates of recurrent cerebral infarction in patients with versus without PFO, and according to PFO-Associated Stroke Causal Likelihood (PASCAL) classification.

RESULTS

Of 2314 included patients, 827 (35.7%) had PFO. During a median follow-up of 4.4 years, cerebral infarction recurred in 202 (8.7%). In multivariate modified Cox regression analyses, recurrence of infarction did not significantly differ between patients with PFO and those without PFO (hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.64-1.17; P = 0.339). Interaction analysis showed a significant effect of PFO in patients < 65 years (adjusted P for interaction = 0.090). PFO was independently associated with a decreased risk of recurrent infarction in patients younger than 65 years (HR, 0.41; 95% CI, 0.20-0.85; adjusted P = 0.016). Patients with probable PFO-associated stroke on the PASCAL classification had a significantly lower risk of recurrent infarction than those without PFO (HR 0.31; 95% CI 0.10-0.97; P=0.044).

INTERPRETATION

Considering the generally low risk of recurrence in PFO-associated stroke, PFO may be the actual cause of stroke in some patients with determined etiologies, especially younger patients or those with PFO features of probable PFO-associated stroke. This article is protected by copyright. All rights reserved.

Stroke of Other Determined Etiology: Results From the Nationwide Multicenter Stroke Registry

BACKGROUND:

Stroke of other determined etiology (OE) includes patients with an uncommon cause of stroke. We described the general characteristics, management, and outcomes of stroke in OE and its subgroups.

METHODS:

This study is a retrospective analysis of a prospective, multicenter, nationwide registry, the Clinical Research Center for Stroke-Korea-National Institutes of Health registry. We classified OE strokes into 10 subgroups according to the literature and their properties. Each OE subgroup was compared according to clinical characteristics, sex, age strata, lesion locations, and management. Moreover, 1-year composites of stroke and all-cause mortality were investigated according to the OE subgroups.

RESULTS:

In total, 2119 patients with ischemic stroke with OE types (mean age, 55.6±16.2 years; male, 58%) were analyzed. In the Clinical Research Center for Stroke-Korea-National Institutes of Health registry, patients with OE accounted for 2.8% of all patients with stroke. The most common subtypes were arterial dissection (39.1%), cancer-related coagulopathy (17.3%), and intrinsic diseases of the arterial wall (16.7%). Overall, strokes of OE were more common in men than in women (58% versus 42%). Arterial dissection, intrinsic diseases of the arterial wall and stroke associated with migraine and drugs were more likely to occur at a young age, while disorders of platelets and the hemostatic system, cancer-related coagulopathy, infectious diseases, and hypoperfusion syndromes were more frequent at an old age. The composite of stroke and all-cause mortality within 1 year most frequently occurred in cancer-related coagulopathy, with an event rate of 71.8%, but least frequently occurred in stroke associated with migraine and drugs and arterial dissection, with event rates of 0% and 7.2%, respectively.

CONCLUSIONS:

This study presents the different characteristics, demographic findings, lesion locations, and outcomes of OE and its subtypes. It is characterized by a high proportion of arterial dissection, high mortality risk in cancer-related coagulopathy and an increasing annual frequency of cancer-related coagulopathy in patients with stroke of OE.

Heart-Brain Relationship in Stroke

The patient presenting with stroke often has cardiac-related risk factors which may be involved in the mechanism of the stroke. The diagnostic assessment is predicated on recognition of this potential relationship. Naturally, an accurate history is of utmost importance in discerning a possible cause and effect relationship. The EKG is obviously an important clue as well as it allows immediate assessment for possible cardiac arrhythmia, such as atrial fibrillation, for possible acute ischemic changes reflective of myocardial ischemia, or there may be indirect factors such as the presence of left ventricular hypertrophy, typically seen with longstanding hypertension, which could be indicative of a hypertensive mechanism for a patient presenting with intracerebral hemorrhage. For all presentations in the emergency room, the vital signs are important. An elevated body temperature in a patient presenting with acute stroke raises concern about possible infective endocarditis. An irregular-irregular pulse is an indicator of atrial fibrillation. A markedly elevated blood pressure is not uncommon in both the acute ischemic and acute hemorrhagic stroke setting. One tends to focus on possible cardioembolic stroke if there is the sudden onset of maximum neurological deficit versus the stepwise progression more characteristic of thrombotic stroke. Because of the more sudden loss of vascular supply with embolic occlusion, seizure or syncope at onset tends to be supportive of this mechanism. Different vascular territory involvement on neuroimaging is also a potential indicator of cardioembolic stroke. Identification of a cardiogenic source of embolus in such a setting certainly elevates this mechanism in the differential. There have been major advances in management of acute cerebrovascular disease in recent decades, such as thrombolytic therapy and endovascular thrombectomy, which have somewhat paralleled the advances made in cardiovascular disease. Unfortunately, the successful limitation of myocardial damage in acute coronary syndrome, with intervention, does not necessarily mirror a similar salutary effect on functional outcome with cerebral infarction. The heart can also affect the brain from a cerebral perfusion standpoint. Transient arrhythmias can result in syncope, while cardiac arrest can result in hypoxic-ischemic encephalopathy. Cardiogenic dementia has been identified as a mechanism of cognitive impairment associated with severe cardiac failure. Structural cardiac abnormalities can also play a role in brain insult, and this can include tumors, such as atrial myxoma, patent foramen ovale, with the potential for paradoxical cerebral embolism, and cardiomyopathies, such as Takotsubo, can be associated with precipitous cardioembolic events.

Immediate and Long-Term Outcomes of Reperfusion Therapy in Patients With Cancer

[Figure: see text].