|Year : 2019 | Volume
| Issue : 2 | Page : 53-56
Transesophageal echocardiography in patients of acute ischemic stroke
Rahul Mehrotra, Raj Kumar, Showkat Hussain Bhat, Bharat Bansal, Mohit Bhagwati
Non Invasive Cardiology, Max Super Specialty Hospital, New Delhi, India
|Date of Web Publication||29-Aug-2019|
Max Super Speciality Hospital, 2, Press Enclave Road, Saket, New Delhi - 110 017
Source of Support: None, Conflict of Interest: None
Background: Approximtely one third of cases of acute ischemic stroke are of undetermined etiology (cryptogenic). Among these cases, cardio embolic tend to be more severe than other causes. Transthoracic echocardiography is used as a standard imaging modality to study structural aspects of heart, however, transesophageal echocardiography (TEE) is a better and much more yielding modality. The present study was carried out in a tertiary care multispecialty hospital to enumerate the findings on TEE in the patients undergoing TEE for “cryptogenic stroke.” Methods: This retrospective observational study was done at our echo lab based on the TEE data of the last 10 years. Sixty-one consecutive adult patients admitted under department of neurology with a diagnosis of acute ischemic stroke and referred for TEE were included in the study. Results: Sixty one consecutive patients of cryptogenic acute ischemic stroke undergoing TEE were studied. Overall, 33% patients had grossly normal TEE findings. Patent foramen ovale (PFO) was the commonest abnormal finding present in 36%, atrial septal aneurysm (ASA) in 18% and both PFO and ASA were present in 18%. No statistical difference was noted between young (0-50 years) and elderly patients (>50 years) with respect to inter atrial septum abnormalities.Twenty eight percent had atheroma in descending aorta. Left atrial appendage clot or spontaneous echo contrast was present in 5% and vegetation was present in 5%. Conclusion: Dilated left atrium was present in 16% and left ventricular dysfunction was present in 18% of the patients. Our results reinforce the idea of a TEE examination in all patients of ischemic stroke which are not explained by routine clinical evaluation and transthoracic echo.
Keywords: Atrial septal aneurysm, patent foramen ovale, stroke, transesophageal echo, transthoracic echo
|How to cite this article:|
Mehrotra R, Kumar R, Bhat SH, Bansal B, Bhagwati M. Transesophageal echocardiography in patients of acute ischemic stroke. J Indian Acad Echocardiogr Cardiovasc Imaging 2019;3:53-6
|How to cite this URL:|
Mehrotra R, Kumar R, Bhat SH, Bansal B, Bhagwati M. Transesophageal echocardiography in patients of acute ischemic stroke. J Indian Acad Echocardiogr Cardiovasc Imaging [serial online] 2019 [cited 2020 Jul 10];3:53-6. Available from: http://www.jiaecho.org/text.asp?2019/3/2/53/265759
| Introduction|| |
Stroke is an acute neurological injury due to brain ischemia or brain hemorrhage. Acute ischemic stroke can further be classified as – thrombotic, embolic, or due to hypoperfusion of the brain tissue. Approximately one-third of acute ischemic strokes do not have any attributable cause and are of undetermined etiology. This subset of ischemic strokes is termed as “Cryptogenic Stroke” in medical literature worldwide. However, it has been recently recognized that this variety of strokes can be further investigated and majority of them have an underlying recognizable etiology. The Trial of Org 10172 in Acute Stroke Treatment classification system also defines stroke of undetermined etiology as those subtypes with two or more potential causes identified, those with a negative evaluation, and those with an incomplete evaluation. In the Atherosclerosis, Small vessel disease, Cardiac source, Other Cause classification, phenotypic subtyping of stroke is done, and the cause is unknown when subtyping does not confer to atherosclerosis (A), small vessel disease (S), cardiac disease (C), or other cause (O). In 2014, the cryptogenic shock/embolic stroke of undetermined source (ESUS) international working group coined the term ESUS for this entity.
Cryptogenic stroke is responsible for 10%–40% of all ischemic strokes. Among all the causes of acute ischemic strokes, cardioembolic stroke has attracted maximal interest in recent years. Cardiac source of embolism can be seen in 15%–40% of all strokes. The reason for interest into the source of emboli can be due to the fact that cardiac embolism causes more severe strokes than any other ischemic stroke subtype  and also because with the range of antiarrhythmics, anticoagulants, antihypertensive, and lipid-lowering drugs, we can prevent recurrence of strokes in these high-risk patients. The common risk factors causing cardioembolic stroke are enumerated in [Table 1]. Importantly, almost all major causes of cardioembolic stroke can be diagnosed by two key investigations – electrocardiogram (ECG) and echocardiography. The most commonly used initial echocardiography modality for this purpose is transthoracic echocardiography (TTE). However, it is not possible to rule out all causes of cardioembolic stroke with TTE alone, and transesophageal echocardiography (TEE) has to be resorted to. TEE provides high-quality images of the patent foramen ovale (PFO), interatrial septum, left atrium (LA), left atrial appendage (LAA), and arch of the aorta, which is not achieved optimally by TTE. For this reason, compared to TTE, TEE is considered superior for identifying a cardiac source of embolism  and in stroke patients with no known cardiac disease; TEE identifies a cardiac source of embolism more frequently than does TTE. Besides, TEE findings also guide in the therapeutic decision-making regarding anticoagulation. This prompted the American Society of Echocardiography (ASE) in 2016 to come up with guidelines for the use of echocardiography in the evaluation of cardiac source of embolism. They advocated the use of TEE as an initial or supplemental test in evaluation of cardiovascular source of embolism in ischemic stroke patients with no identified noncardiac source.
The present study was carried out in a tertiary care multispecialty hospital to enumerate the findings on TEE in the patients undergoing TEE for “cryptogenic stroke.”
| Methods|| |
This retrospective observational study was done at our echo lab based on the TEE data of the last 1½ years. Sixty-one consecutive adult patients admitted under department of neurology with a diagnosis of acute ischemic stroke and referred for TEE were included in the study. Patients with hemorrhagic stroke and patients with previous history of stroke were excluded. A 12-lead ECG was done in all patients and evaluated by a cardiologist. All patients underwent TEE after obtaining informed consent. Comprehensive TEE examination was done using a standard protocol for stroke including the injection of agitated saline contrast  using a 5 MHz multiplane TEE transducer of Philips Epiq 7 system. All chamber dimensions were taken as per the ASE 2015 guidelines update for chamber quantification. LA size was measured by TTE by measuring maximum anteroposterior diameter perpendicular to aortic root axis at the level of aortic sinuses in parasternal long axis view using two-dimensional or M mode. The digitally stored images and test results were accessed and evaluated for the study. TEE was done by an expert cardiologist, and all results were interpreted after consultation with more than one cardiologist. Data were entered in Microsoft (MS) Excel worksheet, and then, computation was done using calculation tool in MS Excel. SPSS 2.0 software (SPSS version 20, IBM) was used to calculate P values.
| Results|| |
Out of the total 61 patients included in the study, 34 were male and 27 were female patients [Table 2]. The mean age of presentation was 52 years.
|Table 2: Prevalence of abnormalities on transesophageal echocardiography|
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Atrial fibrillation (AF) was seen in 23% of the patients in the 12-lead ECG. Twenty (33%) patients had a completely normal TEE examination with no abnormality being detected. Among abnormalities on TEE, PFO was the most common finding (seen in 36% of the patients). Aneurysmal interatrial septum (ASA) was found in 18% of the patients while 18% of the patients had both PFO and ASA. Twelve patients (43%) in the age group of 0–50 years had either PFO or ASA and 10 patients (30%) in the age group >50 years had either PFO or ASA [Table 3]. No statistical difference was noted between young and elderly patients with respect to interatrial septum abnormalities, i.e., PFO or ASA (P = 0.30, Z = 1.01). In total, 28% of patients had atheroma in the descending thoracic aorta. LAA clot or spontaneous echo contrast (SEC) was seen in 5% of the patients and vegetations suggestive of infective etiology were seen in 5% of the patients. LA was found to be dilated in 16% of the patients, and 18% of patients had left ventricular systolic dysfunction with decreased ejection fraction but without clot in the left ventricle (LV).
|Table 3: Agewise distribution of patent foramen ovale or atrial septal aneurysm in stroke patients|
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| Discussion|| |
In this study, we found that routine use of TEE in patients presenting with acute ischemic stroke identifies positive cardiac findings in a significant number of cases. There have been several studies done with TEE in acute ischemic stroke in the past; however, no major study has been done so far in India. The mean age of presentation in our patients was 52 years, and 42% of the patient populations were females. This is consistent with similar studies across the world [Table 4]. In our study, 23% of the patients had AF, a known risk factor for stroke. These patients were referred to us by neurologists to look for the presence of thrombus in the LAA or for other sources of cardioembolic stroke and were therefore included in the study. PFO and ASA have been the most common findings on TEE for stroke patients. Similar results have been seen in our study as well. The most commonly reported finding on TEE was PFO (36%). Our results were consistent with other published data as shown in [Table 4] and [Table 5]. The association of PFO and ischemic stroke however is not established. Case–control studies have reported a positive association; however, the population-based cohort studies report an uncertain association. Likewise, ASA was present in 18% of the stroke patients in our study, and the result is consistent with similar studies done elsewhere. ASA is very frequently associated with PFO. Approximately 56%–84% of the stroke patients, who have an ASA, also have a PFO., In our study also, 18% patients had both PFO and ASA and the incidence of PFO and ASA among the patients of acute stroke was more in younger patients when compared to older patients [Table 3]. This trend in the age-related variation in the incidence of PFO and ASA is consistent with the available literature for agewise incidence of interatrial septum abnormalities in stroke patients., Aortic atheromas of all grades were present in 28% of our patients. These results were comparable to the study done by Dawn et al. where 22% of the patients had aortic atheroma. The diagnosis of aortic atheroma becomes important as the incidence of perioperative stroke during cardiopulmonary bypass surgery is six times higher when aortic arch atheromas are detected on TEE. The incidence of stroke is about 7-fold higher in patients with atheromatous plaques >4 mm in the aortic arch compared to those with plaques in the descending aorta. LA thrombus/SEC was present in 5% of the patients in our study despite the presence of AF in 23% of the patients. This result is comparable to few studies and is in disagreement with others [Table 5]. TEE has 100% sensitivity and 99% specificity in detecting LA thrombus. Therefore, we may attribute this inconsistent result to selection bias or the low number of AF patients in our study group. TTE and TEE have diagnostic sensitivity of 63% and 94%, specificity of 98% and 100%, positive predictive value of 92% and 95%, and negative predictive value of 91% and 100%, respectively., Valvular vegetations were found in 5% patients of our study group; it was less than one of the similar studies. Hence, TEE was found to be very helpful in our study to find cardiac source of embolus in ischemic stroke.
|Table 5: Prevalence of cardiac findings on routine transesophageal echocardiography,,,,|
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| Conclusions|| |
Our study aimed to evaluate patients of ischemic stroke to find a cardiac source of embolus using TEE. Our results reinforce the idea of a TEE examination in all patients of ischemic stroke which are not explained by routine clinical evaluation and transthoracic echo. TEE is a simple semi-invasive test which can be done easily, even at bedside, with minimal danger to the patient. This not only guides us to the source of embolism but also helps us undertake corrective therapeutic interventions to prevent recurrent ischemic strokes. With newer medical therapy of thrombolysis and mechanical removal of thrombus in acute ischemic stroke, the morbidity and mortality of stroke has been decreased over the years; however, deciphering etiology of the ischemic stroke shall further improve the standard of care of this otherwise paralyzing disease.
Of the several limitations of our study, small sample size is one of the major ones. A larger sample size would have given us more clarity on the subject of etiology. Second, there was selection bias, as the study participants were the patients referred by the neurologists for a TEE examination. This may not be a true representative sample of all the patients with cryptogenic stroke. Furthermore, there are problems inherent in retrospective data collection which limits the accuracy of the conclusions being drawn.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]