Biomedical subjects
Stanton K Shernan
Publications and source records attributed to Stanton K Shernan.
Usefulness of intraoperative epiaortic echocardiography to resolve discrepancy between transthoracic and transesophageal measurements of aortic valve gradient - a case report.
PURPOSE: Intraoperative measurement of the aortic valve (AV) gradient in patients undergoing cardiac surgery is routinely performed using transesophageal echocardiography (TEE). In patients with severe aortic stenosis (AS), TEE Doppler beam alignment with the blood flow through the stenotic valve may be inaccurate, resulting in an underestimation of the AV gradient. We describe here the use of epiaortic echocardiography as an alternative to TEE for the intraoperative evaluation of AS. CLINICAL FEATURES: A patient diagnosed with severe AS (peak pressure gradient by transthoracic echocardiography: 108 mmHg) was undergoing AV replacement. In contrast, intraoperative TEE examination performed prior to bypass showed only a mild pressure gradient across the AV (peak pressure gradient: 38 mmHg). In order to resolve the conflicting information, epiaortic echocardiography was used to measure the AV gradient, confirming severe AS (peak pressure gradient: 98 mmHg). Most likely, Doppler beam alignment through the stenotic valve was more parallel to blood flow using epiaortic echocardiography, thus revealing the true pressure gradient. CONCLUSION: Intraoperative epiaortic measurement of AV gradients can be successfully performed in patients where TEE may be inaccurate due to difficulty in aligning a Doppler beam with the transvalvular blood flow.
Images in anesthesia: Detection of a defect pulmonary artery catheter balloon by transesophageal echocardiography.
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Epicardial echocardiography: diagnostic utility for evaluating aortic valve disease during coronary surgery.
Intraoperative epicardial echocardiography is commonly used to evaluate the ascending aorta for atheromatous disease before cannulation and cross clamping. In addition, it may serve as a cardiac imaging technique in patients where placement of a transesophageal echocardiography (TEE) probe is contraindicated, probe advancement is difficult, or a TEE probe is not available. We report a patient who was taken to the OR for coronary artery bypass grafting. Intraoperative TEE was planned to evaluate aortic valve function. However, attempts to place a TEE probe were abandoned due to high resistance on probe insertion. Epicardial echocardiography revealed previously undiagnosed aortic valve disease resulting in replacement of this valve.
A practical approach to a comprehensive epicardial and epiaortic echocardiographic examination.
OBJECTIVE: More than a decade before the introduction of intraoperative transesophageal echocardiography (TEE), epicardial echocardiography was already in use as a diagnostic imaging modality to assist cardiac surgeons and anesthesiologists with clinical decision making. Although TEE has since become increasingly more popular, epicardial echocardiography may be the most convenient intraoperative imaging technique when TEE probe placement cannot be performed or is contraindicated. The authors developed a comprehensive examination protocol for the intraoperative interrogation of cardiac structures using an epicardial/epiaortic echocardiographic approach. DESIGN: Retrospective analysis of patient's medical records. SETTING: Single-center academic tertiary care hospital. PARTICIPANTS: Patients undergoing cardiac surgery. INTERVENTIONS: A total of 10 echocardiographic views were obtained for imaging cardiac structures, the ascending aorta, and proximal aortic arch. The described imaging planes permit the evaluation of ventricular performance, valvular function, cardiac structural abnormalities, and aortic disease. MEASUREMENTS AND MAIN RESULTS: A comprehensive epicardial/epiaortic echocardiographic examination was performed in 20 patients undergoing cardiac surgery requiring a full sternotomy. The described imaging planes were obtained in all patients in less than 8 minutes (range, 3.5-8 minutes; mean, 5.5 minutes). CONCLUSION: The present manuscript delineates a protocol for performing a comprehensive, intraoperative epicardial/epiaortic echocardiographic examination. Echocardiographic imaging planes of cardiac and aortic anatomy are described. This protocol may be useful for cardiac surgeons and anesthesiologists seeking to use this technique as a cardiac imaging modality that is complementary to TEE.
Echocardiographic evidence of right ventricular remodeling after transplantation.
Right ventricular (RV) failure is a significant source of mortality after cardiac transplantation. The use of RV assist devices (RVAD) as a bridge to recovery has been reported. However, early changes of RV structure and anatomy after RVAD implantation have yet to be described. We report a case of RV failure after transplantation requiring RVAD implantation. After 3 weeks of gradual weaning of inotropic and RVAD support, the device was explanted successfully. Transesophageal echocardiography documents RV hypertrophy and remodeling between RVAD implantation and removal, suggesting a rapid adaptive response of the right ventricle in the presence of pulmonary hypertension.
Intraoperative transesophageal echocardiography to assess septic coronary embolism.
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