By Johannes Kaesmacher MD, University Institute of Diagnostic and Interventional Neuroradiology, University Hospital Bern, Switzerland
Complex interactions of the heart and the brain are not confined to everyday life decisions. In acute ischemic stroke, a new research avenue has emerged focusing on the manifold interactions of the heart-brain axis before, during and after an acute ischemic event. Although mechanistically intuitive, the causal association of structural or functional abnormalities of the heart and the etiology of ischemic stroke remains an important field of research.
While echocardiography is the primary imaging modality for cardiac work-up after an acute ischemic stroke, hyperacute cardiac CT imaging offers the unique opportunity to avoid the inherent temporal dissociation of the potentially acute cardio-embolic event, and its diagnostic work-up (usually performed with a delay of 1-3 days). Furthermore, cardiac CT imaging may provide useful information regarding the presence and degree of coronary artery disease, prompting changes concerning the prevention management, and helps to inform treatment decisions in acute ischemic stroke patients with raised Troponin.
However, while promising results of hyperacute cardiac CT scans in acute ischemic stroke have been reported by several research groups (see further reading), many unknowns remain to be resolved. These range from technical consideration and diagnostic yield oriented questions (i.e. mode of electrocardiogram gating), over patient selection, to the overall feasibility of this technique in the acute clinical situation. Several ongoing prospective studies aim at answering some of these important questions.
Let’s take a quick look at some of these studies.
The Mind the Heart cohort study will include 407 consecutive IVT/EVT eligible acute ischemic stroke patients undergoing electrocardiogram-gated CTA of the entire heart brain axis. All of these patients are envisaged to receive transthoracic echocardiography as standard of care, thus allowing for adequate diagnostic accuracy comparisons. The VASCU trial will randomize 260 stroke or transient ischemic attack patients to receive either “routine imaging assessment” or a low-dose, whole-body angiography (including electrocardiogram-gated cardiac CT). The latter can be followed by routine imaging assessments if required. In this trial, the primary outcome will be a compound endpoint defined as the detection of at least one pathology requiring specific treatment/change in management. In the CCT Stroke trial, which is a single group assignment open label trial, a cardiac CT scan will supplement the initial CT angiography of the cerebral and cervical arteries in 400 patients, to assess the prevalence of cardiac thrombus on the cardiac CT scan in the first hours after a cerebral infarction.
While being partially complementary, there are significant differences regarding CT protocols and patient population in the aforementioned trials warranting detailed analysis of the eagerly awaited results.
When interviewing Imogen Cunningham about her favorite photograph she answered “The one I am going to take tomorrow”. We may find out soon whether, in patients with acute ischemic stroke, tomorrow remains the favorite time point for the work-up of cardiac pathologies and echocardiography remains the best-suited camera.
Camen S, Haeusler KG, Schnabel RB. Cardiac Imaging After Ischemic Stroke or Transient Ischemic Attack. Curr. Neurol. Neurosci. Rep. 2020;20:36.
Hur J, Choi BW. Ischemic Stroke: The Role of Cardiac CT. 2019. p. 635–645.
Groeneveld N-S, Guglielmi V, Leeflang MMG, Matthijs Boekholdt S, Nils Planken R, Roos YBWEM, Majoie CBLM, Coutinho JM. CT angiography vs echocardiography for detection of cardiac thrombi in ischemic stroke: a systematic review and meta-analysis. J. Neurol. 2020;267:1793–1801.
Ongoing cohort studies:
VASCU – https://clinicaltrials.gov/ct2/show/NCT02662751?term=cardiac+CT&cond=Stroke&draw=3&rank=17
CCT Stroke – https://clinicaltrials.gov/ct2/show/NCT04261257?term=cardiac+CT&cond=Stroke&draw=2&rank=1
Mind The Heart – Poster available at: https://www.morressier.com/article/mind-heart-cardiac-ctangiography-acute-phase-ischemic-stroke/5b9a8cf9dbd47e000fbf555e
Published emergent cardiac CT together with initial stroke etiologic work-up studies (This list is not intended to be exhaustive):
Popkirov S, Schlegel U, Weber W, Kleffner I, Altenbernd J. Cardiac Imaging Within Emergency CT Angiography for Acute Stroke Can Detect Atrial Clots. Front. Neurol. 2019;10.
Guglielmi V, Planken RN, Mihl C, Niesen S, Staals J, Coutinho JM, Postma AA. Non-gated cardiac CT angiography for detection of cardio-aortic sources of embolism in the acute phase of ischaemic stroke. J. Neurol. Neurosurg. Psychiatry. 2020;91:442–443.
Furtado AD, Adraktas DD, Brasic N, Cheng S-C, Ordovas K, Smith WS, Lewin MR, Chun K, Chien JD, Schaeffer S, et al. The Triple Rule-Out for Acute Ischemic Stroke: Imaging the Brain, Carotid Arteries, Aorta, and Heart. Am. J. Neuroradiol. 2010;31:1290–1296.
Yeo LLL, Holmin S, Andersson T, Lundström E, Gopinathan A, Lim EL, Leong BSH, Kuan W Sen, Ting E, Tan BYQ, et al. Nongated Cardiac Computed Tomographic Angiograms for Detection of Embolic Sources in Acute Ischemic Stroke. Stroke. 2017;48:1256–1261.
Boussel L, Cakmak S, Wintermark M, Nighoghossian N, Loffroy R, Coulon P, Derex L, Cho TH, Douek PC. Ischemic Stroke: Etiologic Work-up with Multidetector CT of Heart and Extra- and Intracranial Arteries. Radiology. 2011;258:206–212.