Ann Thorac Surg 2001;71:1353-1354
© 2001 The Society of Thoracic Surgeons
Case report
Transmitral diagnostic cardioscopy in a coronary artery bypass graft patient
Dumbor L. Ngaage, FRCSa,
Alexander R.J. Cale, FRCSa
a Cardiothoracic Centre, Castle Hill Hospital, Cottingham, East Yorkshire, United Kingdom
Accepted for publication April 12, 2000.
Address reprint requests to Dr Cale, Cardiothoracic Centre, Castle Hill Hospital, Cottingham, East Yorkshire HU16 5JQ, United Kingdom
e-mail: arjcale{at}aol.com
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Abstract
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A 69-year-old man with unstable angina and impaired left ventricular function who was admitted for emergency coronary artery bypass grafting had echocardiographic findings suggestive of a left ventricular thrombus. A transmital cardioscopy was successfully performed at surgery, without video assistance, to confirm the diagnosis. We discuss our approach and the advantages.
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Introduction
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A left ventricular (LV) thrombus in a patient undergoing coronary artery bypass grafting (CABG) needs to be removed at the time of surgery. Sometimes preoperative investigations can be inconclusive and a peroperative procedure is required to resolve the uncertainty. Diagnostic left ventriculotomy should be avoided, if possible, because of its potential complications [1], especially in patients with severely impaired left ventricular function. Diagnostic cardioscopy through the aorta (transaortic cardioscopy) can be performed either by direct insertion of the cardioscope or remotely through the common femoral artery [2–4]. Special endoscopes and equipment for video projection are usually required [2–6]. A transmitral approach has only been mentioned as a possibility [3]. We describe a transmitral diagnostic cardioscopy in a 69-year-old man undergoing emergency CABG.
A 69-year-old man was referred for emergency CABG with unstable angina of 2 weeks duration. He had had two episodes of myocardial infarction 10 and 6 years previously and had fully recovered functionally from a recent left-sided cerebrovascular accident. He was in atrial fibrillation with a ventricular response rate of 82/min, and blood pressure of 140/70 mm Hg. His jugular venous pressure was not raised and cardiac auscultation revealed normal heart sounds. Coronary angiography demonstrated a significant triple vessel disease and an impaired LV function (ejection fraction of 35%). His ventriculogram and transthoracic echocardiography (TTE) were suggestive of LV thrombus.
He was taken to the operating theater within 6 hours of admission. A transesophageal echocardiography preliminary to surgery was inconclusive of a LV thrombus. His chest was opened by median sternotomy, the left internal mammary artery harvested, and he was put on cardiopulmonary bypass. After applying aortic cross-clamp and achieving cardioplegic arrest, a transmitral cardioscopy was performed. A stab incision was made through a 4-0 Prolene pursestring on the right superior pulmonary vein and an LV vent was introduced. The cardioplegia cannula was also used as an aortic root vent. The LV vent was then replaced with a forward viewing Fujinon EG 401 HR fiberoptic endoscope (x1.5 magnification and 120-degree field of view) (Fuji Photo Optical Company Ltd, Tokyo, Japan). The interior of the left atrium was inspected before advancing the endoscope through a normal mitral valve into the left ventricle. This presented an excellent view of the entire LV chamber. There was an area of apical scarring, but no thrombus was seen. The endoscope was withdrawn and the pursestring tied off. Triple CABG was accomplished with two vein conduits to the posterior descending and obtuse marginal arteries, and LIMA to the left anterior descending artery. He was then weaned from cardiopulmonary bypass. He recovered satisfactorily from the operation and was discharged home on postoperative day 7. He was reviewed in the outpatient clinic 3 months after surgery with a check TTE. His TTE findings were similar to those before surgery and he is currently doing well.
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Comment
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The use of video-assisted cardioscopy for diagnosis and treatment of LV pathology has been reported [2, 4, 5]. This spares the patient a left ventriculotomy and its consequent functional disturbance [1]. Additionally cardioscopy provides a better anatomical view of intracardiac structures. Special endoscopes, both rigid and flexible, have been devised for this procedure [3] but they are not commonly available. As a result different types of endoscopes have been used for cardioscopy [2, 5]. The flexible endoscope is less likely than the rigid to cause intracardiac injury, so it is preferred for diagnostic exploration of the heart. The Fujinon EG 401HR fiberoptic endoscope was readily available for use in our patient, and it provided an excellent view of the LV chamber sufficient to exclude the presence of a thrombus. Cardioscopy described in the literature is video-assisted [2–6] and one of its advantages is the visualization of fine details of the LV chamber [4, 6]. When gross pathology is suspected in the LV chamber, as in this patient, unavailability of equipment for video projection should not discourage the procedure. Without video projection, visualization of the LV cavity is adequate to confirm or exclude an LV thrombus. Setting up for video-assisted cardioscopy (which was an adjunctive procedure) in an emergency situation such as this might have delayed and prolonged the operation.
Transaortic cardioscopy is the only endoscopic method of exploring the LV chamber described in the literature. We devised a transmitral approach because it has many advantages. First, it is prograde to blood flow and the direction in which the heart valve opens, and is therefore physiologic. Second, the annulus of the mitral valve is larger than the aortic valve so it can admit an endoscope with less likelihood of injury. Also, the port of insertion of the endoscope in the open technique of transaortic cardioscopy leaves a hole that is bigger than normally required for a top-end anastomosis. In our technique the closure of the port of entry of the endoscope is no different from that of a normal LV vent. Importantly, by avoiding the aorta in patients who are likely to have atherosclerotic plaques, the risk of embolic stroke is reduced. Finally, intracardiac structures are visualized in their anatomical dispositions with transmitral cardioscopy.
In conclusion, cardioscopy can be used to confirm or exclude the presence of LV thrombus in a CABG patient when preoperative investigations are inconclusive. The unavailability of special cardioscopes and video assistance does not preclude adequate visualization. Transmitral cardioscopy is a more physiological method of endoscopic evaluation of the left ventricle than diagnostic transaortic cardioscopy.
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References
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Abstract
Introduction
