Expert opinion paper on cardiac imaging after ischemic stroke

Enhanced diagnostic workup increases pathological findings in patients with acute ischaemic stroke: results of the prospective HEBRAS study

BACKGROUND

Stroke aetiology remains cryptogenic in a relevant proportion of patients with acute ischaemic stroke (AIS). We assessed whether enhanced diagnostic workup after AIS yields a higher rate of prespecified pathological findings compared with routine diagnostic care in-hospital.

METHODS

Hospitalised patients with AIS were prospectively enrolled in the investigator-initiated observational HEart and BRain Interfaces in Acute Ischaemic Stroke (HEBRAS) study at the Charité, Berlin, Germany. Patients with AIS without known atrial fibrillation (AF) underwent cardiovascular MR imaging (CMR), MR-angiography of the aortic arch and prolonged Holter-ECG monitoring on top of routine diagnostic care.

RESULTS

Among 356 patients with AIS (mean age 66 years, 37.6% female), enhanced workup yielded a higher rate of prespecified pathological findings compared with routine care (17.7% vs 5.3%; p<0.001). Consequently, fewer patients were classified as cryptogenic after enhanced diagnostic workup (38.5% vs 45.5%, p<0.001). Routine care included echocardiography in 228 (64.0%) patients. CMR was successfully performed in 292 (82.0%) patients and revealed more often a prespecified pathological finding compared with routine echocardiography (16.1% vs 5.3%). Furthermore, study-related ECG monitoring (median duration 162 hours (IQR 98-210)) detected AF in 16 (4.5%) patients, while routine monitoring (median duration 51 hours (IQR 34-74)) detected AF in seven (2.0%) patients.

CONCLUSIONS

Enhanced diagnostic workup revealed a higher rate of prespecified pathological findings in patients with AIS compared with routine diagnostic care and significantly reduced the proportion of patients with cryptogenic stroke.

TRIAL REGISTRATION NUMBER

NCT02142413.

Etiologic subtypes of first and recurrent ischemic stroke in young patients using A-S-C-O and TOAST classification criteria: A retrospective follow-up study

INTRODUCTION

Scarce data exist on the etiology of recurrent ischemic strokes (ISs) among young adults. We analyzed the etiology of first-ever and recurrent events and the differences between them.

PATIENTS AND METHODS

Patients aged 15-49 years with a first-ever IS in 1994-2007 were included in the Helsinki Young Stroke Registry. In this retrospective cohort study, data on recurrent ISs were identified from Care Register for Health Care until the end of 2017 and Causes of Death Register and from patient records until the end of 2020. All first-ever and recurrent ISs were classified using Atherosclerosis-Small vessel disease-Cardioembolism-Other Cause (A-S-C-O) and Trial of Org 10172 in Acute Stroke Treatment (TOAST) classifications.

RESULTS

A total of 970 patients were included (median age at index IS 46 years, interquartile range 43-48, 33% women), of which 155 (16.0%) patients had recurrent IS, with 8 (5.2%) fatal cases and 5 (3.2%) unverifiable cases. The median follow-up was 17.4 (IQR 13.9-21.7) years. Median time from the index event to the first recurrent event was 4.5 (interquartile range [IQR] 1.6-10.2) years. Recurrence was more often due to definite cardioembolism (10.7% vs 18.0%, p = 0.013), while the proportion of other definite A-S-C-O subgroups remained the same. With TOAST classification, the proportion of true cryptogenic ISs decreased (16.7% vs 6.7%, p = 0.003), while those with incomplete evaluation increased (9.3% vs 19.3%, p = 0.015). Other TOAST phenotypes remained the same.

CONCLUSION

The proportion of definite cardioembolism increased at recurrence using the A-S-C-O classification and the number of cryptogenic ISs decreased using the TOAST classification, while cases with incomplete evaluation increased. Most etiologies remained the same.

Multimodal Cardiac Imaging in the Assessment of Patients Who Have Suffered a Cardioembolic Stroke: A Review

Cardioembolic strokes account for 20-25% of all ischaemic strokes, with their incidence increasing with age. Cardiac imaging plays a crucial role in identifying cardioembolic causes of stroke, with early and accurate identification affecting treatment, preventing recurrence, and reducing stroke incidence. Echocardiography serves as the mainstay of cardiac evaluation. Transthoracic echocardiography (TTE) is the first line in the basic evaluation of structural heart disorders, valvular disease, vegetations, and intraventricular thrombus. It can be used to measure chamber size and systolic/diastolic function. Trans-oesophageal echocardiography (TOE) yields better results in identifying potential cardioembolic sources of stroke and should be strongly considered, especially if TTE does not yield adequate results. Cardiac computed tomography and cardiac magnetic resonance imaging provide better soft tissue characterisation, high-grade anatomical information, spatial and temporal visualisation, and image reconstruction in multiple planes, especially with contrast. These techniques are useful in cases of inconclusive echocardiograms and can be used to detect and characterise valvular lesions, thrombi, fibrosis, cardiomyopathies, and aortic plaques. Nuclear imaging is not routinely used, but it can be used to assess left-ventricular perfusion, function, and dimensions and may be useful in cases of infective endocarditis. Its use should be considered on a case-by-case basis. The accuracy of each imaging modality depends on the likely source of cardioembolism, and the choice of imaging approach should be tailored to individual patients.

Advances in Cardiac Workup for Transient Ischemic Attack: Improving Diagnostic Yield and Reducing Recurrent Stroke Risk

Transient ischemic attack (TIA) is a warning sign for an impending stroke, with a 10-20% chance of a stroke occurring within 90 days of the initial event. Current clinical practice for cardiac workup in TIA includes cardiac enzymes, with 12-lead electrocardiogram, transthoracic echocardiography, and 24-hour Holter monitoring. However, the diagnostic yield of these investigations is variable, and there is a need for better diagnostic approaches to increase the detection of cardiac abnormalities in a cost-effective way. This review article examines the latest research on emerging diagnostic tools and strategies and discusses the potential benefits and challenges of using these advanced diagnostic approaches in clinical practice. Novel biomarkers, imaging techniques, and prolonged rhythm monitoring devices have shown great promise in enhancing the diagnostic yield of cardiac workup in TIA patients. Echocardiography, Transcranial Doppler ultrasound, cardiac MRI, and cardiac CT are among the promising diagnostic tools being studied. We conclude the article with a suggested diagnostic algorithm for cardiac workup in TIA. Further research is necessary to enhance their usefulness and to outline future directions for research and clinical practice in this field.

Extent of routine diagnostic cardiac work-up at certified German stroke units participating in the prospective MonDAFIS study

BACKGROUND

About 25% of all ischaemic strokes are related to cardio-embolism, most often due to atrial fibrillation (AF). Little is known about the extent and standardization of routine cardiac diagnostic work-up at certified stroke-units in Germany.

METHODS

The MonDAFIS study included non-AF patients with acute ischaemic stroke or transient ischaemic attack (TIA) at 38 certified stroke-units in Germany. Here, we analysed routine diagnostic work-up and disregarded study-related Holter-ECG monitoring. We compared duration of stroke-unit stay, number of 24-h Holter-ECGs, and echocardiography performed between university-based comprehensive stroke centres (UCSC, 12 hospitals, 1606 patients), non university-based comprehensive stroke centres (nUCSC, 14 hospitals, 892 patients), and primary stroke centres at non-university hospitals (PCS, 12 hospitals, 933 patients) using multivariable mixed regression analyses. Detection of a first AF episode in-hospital was also compared between hospitals of different stroke-unit levels.

RESULTS

In 3431 study patients (mean age 66.2 years, 39.5% female, median NIHSS = 2 on admission), median duration of the stroke-unit stay was 72 h (IQR 42-86). Stroke-unit stay was longer (categorised ≤ 24/ > 24- ≤ 72/ > 72 h) for patients with severe stroke (NIHSS score ≥ 5/ < 5: OR = 1.6, 95%CI 1.3-2.0) and for patients with ischaemic stroke vs. TIA (OR = 1.7, 95%CI 1.4-2.1). Overall, 2149/3396 (63.3%) patients underwent at least one additional 24-h Holter-ECG (median 1 [IQR 0-1], range 0-7). Holter-ECG rate was 47% in UCSC, 71% in nUCSC, and 84% in PCS. Compared to PCS, AF was less often detected in-hospital in UCSC (OR = 0.65, 95%CI 0.45-0.93) and nUCSC (OR = 0.69, 95%CI 0.46-1.04). Transoesophageal echocardiography (TEE) only was performed in 513/3391 (15.1%) study patients, transthoracic echocardiography (TTE) only in 1228/3391 (36.2%), and TEE combined with TTE in 1020/3391 (30.1%) patients. Patients younger than 60 years (vs. ≥ 60 years) underwent TEE more often than those older than 60 years (OR = 3.44, 95%CI 2.67-4.42). TEE (IQR 34-65%) and TTE rate (IQR 40-85%) varied substantially among study centres. Echocardiography rate (TTE and/or TEE) was 74.0% in UCSC, 85.4% in nUCSC, and 90.3% in PSC, respectively.

CONCLUSIONS

In the MonDAFIS study, the routine use of echocardiography and Holter-ECG monitoring varied in participating stroke centres and at stroke-unit level, if grouped according to stroke-unit certification grade and hospitals´ university status. Trial registration Clinical Trials, NCT02204267. Registered 30 July 2014, https://clinicaltrials.gov/ct2/show/NCT02204267 .

Spectral cardiac CT in acute stroke patients

Cardiac CT obtained in acute ischemic stroke patients can facilitate timely detection of cardiac sources of embolism and guide secondary prevention strategies. Spectral CT exploiting the simultaneous acquisition of separate higher-energy and lower-energy photon spectrum datasets has the potential to improve contrast between thrombi and cardiac structures. This study aimed to investigate the diagnostic value of spectral cardiac CT compared to conventional CT for the detection of cardiac thrombi in acute stroke patients. Patients with acute ischemic stroke undergoing spectral cardiac CT were retrospectively included. Conventional CT images, virtual 55 keV monoenergetic (monoE55), z-effective (zeff), and iodine density images were evaluated for the presence of thrombi. Diagnostic certainty was rated on a 5-point Likert scale. Contrast ratios were calculated for all reconstructions. 63 patients with 20 thrombi were included. Four thrombi were missed on conventional images but detected on spectral reconstructions. MonoE55 achieved the highest scores for diagnostic certainty. Contrast ratios were highest on iodine density images, followed by monoE55, conventional and zeff (p < 0.005). Spectral cardiac CT adds diagnostic benefit for the detection of intra-cardiac thrombi in acute ischemic stroke patients compared to conventional CT.

Imaging in atrial fibrillation: A way to assess atrial fibrosis and remodeling to assist decision-making

The 2020 ESC atrial fibrillation (AF) guidelines suggest the novel 4S-AF scheme for the characterization of AF. Imaging techniques could be helpful for this objective in everyday clinical practice, and information derived from these techniques reflects basic aspects of the pathophysiology of AF, which may facilitate treatment decision-making, and optimal management of AF patients. The aim of this review is to provide an overview of the mechanisms associated with atrial fibrosis and to describe imaging techniques that may help the management of AF patients in clinical practice. Transthoracic echocardiography is the most common procedure given its versatility, safety, and simplicity. Transesophageal echocardiography provides higher resolution exploration, and speckle tracking echocardiography can provide incremental functional and prognostic information over conventional echocardiographic parameters. In addition, LA deformation imaging, including LA strain and strain rate, are related to the extent of fibrosis. On the other hand, multidetector-row computed tomography and cardiac magnetic resonance provide higher resolution data and more accurate assessment of the dimensions, structure, and spatial relationships of the LA. Imaging is central when deciding on catheter ablation or cardioversion, and helps in selecting those patients who will really benefit from these procedures. Moreover, imaging enhances the understanding of the underlying mechanisms of atrial remodeling and might assists in refining the risk of stroke, which help to select the best medical therapies/interventions. In summary, evaluation of LA enlargement, LA remodeling and fibrosis with imaging techniques adds clinical and prognostic information and should be assessed as a part of routine comprehensive AF evaluation.

Echocardiography in acute stroke patients: a nationwide analysis in departments with certified stroke units in Germany

BACKGROUND

Echocardiography is highly relevant in patients with ischemic stroke or TIA. Utilization of routine echocardiographic examinations [transthoracic (TTE) or transesophageal (TEE)] on stroke units remains however unknown. To representatively examine echocardiographic rates on stroke units in Germany and to evaluate structural factors that may influence the decision to conduct echocardiography.

METHODS

A nationwide analysis was performed by using certification audit data of all primary and comprehensive stroke centers (pSC and cSC) in Germany.

RESULTS

Structural and organizational requirements of 310 departments (cSCs: 42.6%) were extracted. Median TTE rate was 63.3% (IQR 39.3-80.8), median TEE rate 21.3% (IQR 16.4-29.5). A cardiological department on site was present in 74.2%, and they were associated with higher TEE rates. TTE rates decreased with increasing numbers of patients (p = 0.026). Likewise, TEE rates decreased with increasing numbers of patients (p = 0.006), mediated by departments with cSCs (p = 0.008 for cSCs vs p = 0.230 for pSCs). TTE rates were far more inhomogeneously distributed than TEE rates and higher in pSCs (p = 0.011). Overall, 12.9% of centers did not perform any echocardiographic examination in at least 50% of all stroke patients.

CONCLUSION

More detailed recommendations regarding echocardiography should be included in future guidelines. Moreover, evaluating the impact of echocardiographic examinations on long-term prognosis in stroke patients should be focus of further evaluations.

[Patent foramen ovale as the cause of recurrent embolic strokes. Case report]

А clinical case of a young patient with recurrent ischemic strokes is presented. The problems of diagnostic embolic strokes are discussed. We set out the algorithm for identifying patients, in whom patent foramen ovale is the most probable cause of embolic stroke. Detailed consideration of imaging diagnostic methods possibility is included. Hypothesis of probable source of cardioembolism from patent foramen ovale is presented. Recommendations for the secondary prevention of recurrent ischemic stroke, associated with patent foramen ovale, are provided. We also considered the issues of antithrombotic treatment.

Atrial Cardiomyopathy: Pathophysiology and Clinical Consequences

Around the world there are 33.5 million patients suffering from atrial fibrillation (AF) with an annual increase of 5 million cases. Most AF patients have an established form of an atrial cardiomyopathy. The concept of atrial cardiomyopathy was introduced in 2016. Thus, therapy of underlying diseases and atrial tissue changes appear as a cornerstone of AF therapy. Furthermore, therapy or prevention of atrial endocardial changes has the potential to reduce atrial thrombogenesis and thereby cerebral stroke. The present manuscript will summarize the underlying pathophysiology and remodeling processes observed in the development of an atrial cardiomyopathy, thrombogenesis, and atrial fibrillation. In particular, the impact of oxidative stress, inflammation, diabetes, and obesity will be addressed.