Silent Myocardial Infarction and Subsequent Ischemic Stroke in the Cardiovascular Health Study

Silent Myocardial Infarction and Risk of Stroke Recurrence: A Post Hoc Analysis of the IRIS Trial

BACKGROUND

Unrecognized or silent myocardial infarction (MI) detected on an ECG is associated with first-ever stroke, but the impact on stroke recurrence is unknown. We aimed to determine the association of silent MI with stroke recurrence in patients with a recent ischemic stroke.

METHODS AND RESULTS

Subjects from the IRIS (Insulin Resistance Intervention After Stroke) trial with an available ECG were included. Clinical MI was defined as a history of hospitalization for MI. Silent MI was defined as ECG evidence of MI in the absence of clinical MI. The primary outcome was recurrent stroke. Ischemic stroke and subtype were assessed as secondary outcomes. Multivariable Cox regression analysis adjusted for demographics, pioglitazone, and vascular risk factors was used to examine the association between MI and stroke recurrence. A total of 2282 participants met the inclusion criteria. Clinical and silent MI were identified in 161 (7.1%) and 94 (4.1%) subjects, respectively. Over the study period, 209 recurrent strokes occurred, with 191 classified as ischemic. In the fully adjusted model, silent MI was significantly associated with any stroke (hazard ratio [HR], 2.29 [95% CI, 1.34-3.90]) and ischemic stroke (HR, 2.09 [95% CI, 1.18-3.70]) recurrence. Clinical MI was associated with stroke recurrence in the unadjusted analysis but not in the fully adjusted model (HR, 1.31 [95% CI, 0.81-2.11]). Silent MI was not associated with potential cardioembolic subtypes (HR, 1.50 [95% CI, 0.70-3.22]).

CONCLUSIONS

Among patients with a recent ischemic stroke, silent MI was associated with stroke recurrence. Tailored prevention strategies in this population warrant future investigation.

REGISTRATION

URL: https://clinicaltrials.gov. Unique Identifier: NCT00091949.

Cardiac CT in Large Vessel Occlusion Stroke for the Evaluation of Non-Thrombotic and Non-Atrial-Fibrillation-Related Embolic Causes

Background: The purpose of this study is the evaluation of imaging findings of acute-phase cardiac CT (cCT) in stroke patients with large vessel occlusion (LVO) to identify potential cardioembolic sources (CES) in patients without intracardiac thrombi and atrial fibrillation (AF). Material and Methods: This retrospective study included 315 patients with LVO who underwent cCT imaging in the acute stroke setting. The images were analysed for 15 imaging findings following the established minor and major cardioembolic risk factors. The final stroke aetiology was determined using the TOAST classification through interdisciplinary consensus following a thorough clinical evaluation. Multivariate regression analysis was performed to identify imaging findings associated with CES. Results: A cardioembolic aetiology was identified on cardiac CT in 211 cases (70%). After adjustment for AF and intracardiac thrombi, the multivariate regression analysis revealed significant associations with left ventricular dilation (adjusted odds-ratio (AOR) 32.4; 95% CI 3.0-349; p = 0.004), visible interatrial right-to-left shunt (AOR 30.8; 95% CI 2.7-341.3; p = 0.006), valve implants (AOR 24.5; 95% CI 2.2-270.9; p = 0.009), aortic arch atheroma grade > II (AOR 6.9; 95% CI 1.5-32.8; p = 0.015) and post-ischaemic myocardial scars (AOR 6.3, 95% CI 1.2-34.1; p = 0.032) as independent risk factors for a cardioembolic aetiology. The combined model achieved an area under the ROC curve of 0.83. Conclusions: In patients with LVO without AF and intracardiac thrombi as a cause, the presence of left ventricular dilatation, interatrial right-to-left shunts, valve implants, post-ischaemic myocardial scarring and advanced aortic arch atheroma (grade > 2) in particular is significantly associated with a cardioembolic cause of stroke and should be add-on evaluated in acute-phase cCT. Further investigations are warranted to confirm these associations.

Effect of Intensive Blood Pressure Lowering on the Risk of Incident Silent Myocardial Infarction: A Post Hoc Analysis of a Randomized Controlled Trial

BACKGROUND

Silent myocardial infarction (SMI) frequently goes undetected, yet it is associated with increased cardiovascular morbidity and mortality. The impact of intensive systolic blood pressure (SBP) lowering on the risk of SMI in those with hypertension remains uncertain.

METHODS

In this post hoc analysis of the Systolic Blood Pressure Intervention Trial (SPRINT), participants with serial electrocardiograms (ECGs) during the trial were included. SPRINT investigated the benefit of intensive SBP lowering, aiming for < 120 mmHg compared to the standard SBP goal of < 140 mmHg. Incident SMI was defined as evidence of new MI on an ECG without adjudicated recognized myocardial infarction (RMI).

RESULTS

During a median follow-up of 3.9 years, a total of 234 MI events (55 SMI and 179 RMI) occurred. Intensive, compared to standard, SBP lowering resulted in a lower rate of SMI (incidence rate 1.1 vs. 2.3 cases per 1000 person-years, respectively; HR [95% CI]: 0.48 [0.27-0.84]). Similarly, intensive, compared to standard, BP lowering reduced the risk of RMI (incidence rate 4.6 vs. 6.5 cases per 1000 person-years, respectively; HR [95% CI]: 0.71 [0.52-0.95]). No significant differences were noted between the strength of the association of intensive BP control on lowering the risk of SMI and RMI (p-value for HR differences = 0.23).

CONCLUSIONS

This study shows that in adults with hypertension, the benefits of intensive SBP lowering, compared with standard BP lowering, go beyond the prevention of RMI to include the prevention of SMI.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01206062.

Adherence to Dietary Approaches to Stop Hypertension (DASH) Diet as a Protective Factor for Ischemic Stroke and Its Influence on Disability Level: A Case-Control Study in Lebanon

BACKGROUND

Hypertension is a major risk factor for ischemic stroke. An important strategy in controlling hypertension is dietary modification. The present study evaluates the effect of Dietary Approaches to Stop Hypertension (DASH) diet on the risk of ischemic stroke.

METHODS

A case-control study was carried out, including 214 ischemic stroke cases recruited within the first 48 h of diagnosis and 214 controls, divided equally into hospitalized and non-hospitalized participants. Controls were matched to cases based on age and gender. Socio-demographic characteristics were assessed, in addition to adherence to the DASH diet, which was measured using a preconstructed DASH diet index (ranging from 0 (lowest) to 11 (highest)). For stroke patients, Modified Rankin Score (mRS) was measured to assess disability.

RESULTS

Smoking, hypertension, hyperlipidemia, atrial fibrillation, and myocardial infarction were significantly associated with ischemic stroke (p < 0.001). Higher adherence to the DASH diet was correlated to lower rates of stroke, where cases scored 5.042 ± 1.486 compared to 6.654 ± 1.471 for controls (p < 0.001). Eating more grains, vegetables, fruits, dairy products, nuts, seeds, and beans, and lower levels of fat, fewer sweets, and less sodium were associated with lower rates of ischemic stroke (p = 0.038 for sweets and p < 0.001 for all the remaining), while meat, poultry, and fish did not have any significant effect (p = 0.46). A multivariate analysis showed that lower adherence to the DASH diet (p < 0.001, OR: 0.526, CI95% 0.428-0.645) was associated with a higher incidence of ischemic stroke and an increased likelihood of having high disability levels (mRS 5-6) (p = 0.041, OR: 2.49 × 10-8, CI95% 0-2.49 × 10-8).

CONCLUSIONS

The relation between the DASH diet and risk of stroke highlights the necessity for strict adherence to dietary restrictions, suggesting a protective role for the DASH diet in stroke pathogenesis and prognosis.

Identification of key biomarkers for predicting CAD progression in inflammatory bowel disease via machine-learning and bioinformatics strategies

The study aimed to identify the biomarkers for predicting coronary atherosclerotic lesions progression in patients with inflammatory bowel disease (IBD). Related transcriptome datasets were seized from Gene Expression Omnibus database. IBD-related modules were identified via Weighted Gene Co-expression Network Analysis. The 'Limma' was applied to screen differentially expressed genes between stable coronary artery disease (CAD) and acute myocardial infarction (AMI). Subsequently, we employed protein-protein interaction (PPI) network and three machine-learning strategies to further screen for candidate hub genes. Application of the receiver operating characteristics curve to quantitatively evaluate candidates to determine key diagnostic biomarkers, followed by a nomogram construction. Ultimately, we performed immune landscape analysis, single-gene GSEA and prediction of target-drugs. 3227 IBD-related module genes and 570 DEGs accounting for AMI were recognized. Intersection yielded 85 shared genes and mostly enriched in immune and inflammatory pathways. After filtering through PPI network and multi-machine learning algorithms, five candidate genes generated. Upon validation, CTSD, CEBPD, CYP27A1 were identified as key diagnostic biomarkers with a superior sensitivity and specificity (AUC > 0.8). Furthermore, all three genes were negatively correlated with CD4+ T cells and positively correlated with neutrophils. Single-gene GSEA highlighted the importance of pathogen invasion, metabolism, immune and inflammation responses during the pathogenesis of AMI. Ten target-drugs were predicted. The discovery of three peripheral blood biomarkers capable of predicting the risk of CAD proceeding into AMI in IBD patients. These identified biomarkers were negatively correlated with CD4+ T cells and positively correlated with neutrophils, indicating a latent therapeutic target.

Role of cardiac computed tomography in hyperacute stroke assessment

BACKGROUND

Incorporating cardiac CT with hyperacute stroke imaging may increase the yield for cardioembolic sources. It is not clarified whether stroke severity influences on rates of intracardiac thrombus. We aimed to investigate a National Institutes of Health Stroke Scale (NIHSS) threshold below which acute cardiac CT was unnecessary.

METHODS

Consecutive patients with suspected stroke who underwent multimodal brain imaging and concurrent non-gated cardiac CT with delayed timing were prospectively recruited from 1st December 2020 to 30th November 2021. We performed receiver operating characteristics analysis of the NIHSS and intracardiac thrombus on hyperacute cardiac CT.

RESULTS

A total of 314 patients were assessed (median age 69 years, 61% male). Final diagnoses were ischemic stroke (n=205; 132 etiology-confirmed stroke, independent of cardiac CT and 73 cryptogenic), transient ischemic attack (TIA) (n=21) and stroke-mimic syndromes (n=88). The total yield of cardiac CT was 8 intracardiac thrombus and 1 dissection. Cardiac CT identified an intracardiac thrombus in 6 (4.5%) with etiology-confirmed stroke, 2 (2.7%) with cryptogenic stroke, and none in patients with TIA or stroke-mimic. All of those with intracardiac thrombus had NIHSS ≥4 and this was the threshold below which hyperacute cardiac CT was not justified (sensitivity 100%, specificity 38%, positive predictive value 4.0%, negative predictive value 100%).

CONCLUSIONS

A cutoff NIHSS ≥4 may be useful to stratify patients for cardiac CT in the hyperacute stroke setting to optimize its diagnostic yield and reduce additional radiation exposure.

Chronic Low Back Pain and Incident Transient Ischemic Attack and Stroke in General Practices in Germany

The aim was to investigate the association between chronic low back pain (CLBP) and incident transient ischemic attack (TIA) and stroke in Germany. The present retrospective cohort study included adults aged ≥18 years who were diagnosed for the first time with CLBP in one of 1198 general practices in Germany in 2005-2019 (index date). Patients without CLBP were matched to those with CLBP (1:1) using a propensity score based on age, sex, the index year, the number of medical consultations per year during the follow-up, and the number of years of follow-up. In patients without CLBP, the index date was a randomly selected visit date. Both groups were followed for up to 10 years. There were 159,440 patients included in the study (mean (SD) age: 52.1 (16.5) years; 51.5% women). Within 10 years of the index date, 6.5% and 5.9% of patients with and without CLBP were diagnosed with TIA or stroke, respectively (log-rank p-value < 0.001). The Cox regression analysis corroborated these results, as there was a significant association between CLBP and incident TIA or stroke (HR = 1.28, 95% CI = 1.22-1.35). CLBP was positively and significantly associated with incident TIA and stroke in Germany. More research is warranted to better understand this relationship.

Diagnosis and Management of Cardioembolic Stroke

OBJECTIVE

Cardioembolic stroke accounts for nearly 30% of ischemic strokes. Prompt diagnosis of the underlying mechanism may improve secondary prevention strategies. This article reviews recent randomized trials, observational studies, case reports, and guidelines on the diagnosis and treatment of cardioembolic stroke.

LATEST DEVELOPMENTS

Several pathologies can lead to cardioembolic stroke, including atrial fibrillation, aortic arch atheroma, patent foramen ovale, left ventricular dysfunction, and many others. Secondary stroke prevention strategies differ across these heterogeneous mechanisms. In addition to medical treatment advances such as the use of direct oral anticoagulants in patients with atrial fibrillation, surgical treatments such as closure of patent foramen ovale have been shown to reduce the risk of recurrent stroke in select patients. Furthermore, left atrial appendage occlusion is a promising strategy for patients with atrial fibrillation who are candidates for short-term oral anticoagulation therapy but not long-term oral anticoagulation therapy.

ESSENTIAL POINTS

A thorough diagnostic evaluation is essential to determine cardioembolic causes of stroke. In addition to risk factor management and lifestyle modifications, identification and targeting of the underlying cardioembolic stroke mechanisms will lead to improved stroke prevention strategies in patients with cardioembolic stroke.

Large vessel occlusions requiring repeated mechanical thrombectomy caused by silent myocardial infarction in a young adult

OBJECTIVES

Silent myocardial ischemia, defined as objective evidence of myocardial ischemia without symptoms, is associated with ischemic stroke. Nevertheless, silent myocardial infarction is a rare cause of ischemic stroke, especially in young adults with no medical history.

MATERIALS AND METHODS

Herein, we report a young adult patient with acute ischemic stroke treated with repeated mechanical thrombectomy for recurrent large vessel occlusions caused by left ventricular thrombus following a silent myocardial infarction.

RESULTS

A 40-year-old man was transferred by ambulance to our hospital because of a generalized seizure. He was diagnosed with cerebral infarction and left middle cerebral artery occlusion. We performed intravenous thrombolysis and mechanical thrombectomy. Recanalization was achieved and his symptoms gradually improved. However, the day after treatment he developed bilateral cerebellar infarction and basilar artery occlusion. We performed a second mechanical thrombectomy and recanalization was achieved. Transthoracic echocardiography revealed a mobile left ventricular thrombus. Although he had no previous chest symptomatic episodes, cardiac examination confirmed myocardial infarction of unknown onset. He was diagnosed with acute ischemic stroke with large vessel occlusions caused by left ventricular thrombus following a silent myocardial infarction. Anticoagulation therapy reduced the amount of thrombus. At 1-year follow-up, he had not experienced any recurrences or symptoms.

CONCLUSIONS

Silent myocardial infarction should be considered a cause of ischemic stroke in young adults, even without any vascular risk factors. Recurrent large vessel occlusion may occur in patients with left ventricular thrombus, and repeated mechanical thrombectomy should be considered for treatment.

Advances in Recurrent Stroke Prevention: Focus on Antithrombotic Therapies

The past decade has seen significant advances in stroke prevention. These advances include new antithrombotic agents, new options for dyslipidemia treatment, and novel techniques for surgical stroke prevention. In addition, there is greater recognition of the benefits of multifaceted interventions, including the role of physical activity and dietary modification. Despite these advances, the aging of the population and the high prevalence of key vascular risk factors pose challenges to reducing the burden of stroke. Using a cause-based framework, current approaches to prevention of cardioembolic, cryptogenic, atherosclerotic, and small vessel disease stroke are outlined in this paper. Special emphasis is given to recent trials of antithrombotic agents, including studies that have tested combination treatments and responses according to genetic factors.