Transesophageal echocardiography predicts successful withdrawal of ventricular assist devices.

Transesophageal echocardiography has been found to be an effective technique for the real-time assessment of myocardial and valvular function in postoperative patients. To determine the value of transesophageal echocardiography in patients with mechanical assist devices, we performed daily, bedside transesophageal echocardiography on 16 patients with right (n = 3), left (n = 1), or biventricular assist devices (n = 12). We obtained four-chamber and short-axis views in all patients. Valvular function and the presence of left-to-right shunts were evaluated by means of color flow Doppler imaging. During the echocardiographic study ventricular assist device flow was diminished to less than 1.5 L/min, and inotropic agents (dobutamine or epinephrine) were given to assess ventricular reserve. Changes in day-to-day ventricular function were assessed in comparisons made by two observers (one unaware of the study sequence) using a semiquantitative method for wall motion analysis. The left ventricular wall motion scores in the patients successfully weaned from left or biventricular assist devices (n = 5) improved (14.2 +/- 1.6 versus 8.2 +/- 1.5, p < 0.0001). The scores did not improve in patients who remained dependent on the devices (n = 8). Two patients with only right ventricular assist devices were successfully weaned after documentation of improvement of right ventricular function by transesophageal echocardiography. Transesophageal echocardiography documented a clot compressing the heart in three patients; intracavitary thrombi were seen in two other patients. Marked hemodynamic improvement occurred after surgical decompression. In conclusion, transesophageal echocardiography is a safe, effective method for the assessment of ventricular function of patients on ventricular assist device support. In addition, it allows one to assess valvular function and the presence or absence of impaired ventricular filling.     

Current status of mechanical circulatory assistance

Mechanical circulatory support has become an increasingly used management strategy for patients with both acute and chronic ventricular failure. This article briefly reviews the current state of mechanical circulatory support with a focus on indications, contraindications, and complications of currently available devices. Perioperative considerations for ventricular assist device implantation are discussed, including the decision-making process underlying the use of univentricular versus biventricular support, specific anesthetic considerations, and the role of transesophageal echocardiography where ventricular assist devices are concerned. The anesthetic considerations for the patient already supported by a ventricular assist device presenting for noncardiac surgery are also reviewed. The work concludes with a discussion of the rationale behind the next generation of continuous flow devices currently in human clinical trials.     

Timing of transesophageal echocardiography in diagnosing patent foramen ovale in patients supported with left ventricular assist device

Left ventricular assist devices unload the left ventricle and decrease left atrial pressure. This hemodynamic change may cause a right to left atrial shunt and hypoxemia in patients with patent foramen ovale. We prospectively studied the best time for performing diagnostic transesophageal echocardiography in left ventricular assist device patients. Intraoperative transesophageal echocardiography was performed in 14 patients before cardiopulmonary bypass was initiated and after left ventricular assist device was implanted. No patent foramen ovale was detected when transesophageal echocardiography was done before bypass, but a patent foramen ovale was found in 3 patients when transesophageal echocardiography was performed after left ventricular assist device was activated. Patent foramen ovale was confirmed by inspection in all three patients and surgically closed during the same procedure. There were no patent foramen ovale closure-related complications.     

Transesophageal echocardiography in the intensive care unit

Transesophageal echocardiography provides unique diagnostic capabilities, allowing for a very precise look at the structure and hemodynamics of the human heart. It is minimally invasive and portable, and quickly diagnoses sudden hemodynamic changes in intensive care patients. It provides invaluable and precise information about myocardial dysfunction and intracardiac volume status. It can diagnose dynamic left ventricular outflow obstruction, infrequent but serious complication of aortic valve replacement, septal myectomy, or mitral valve repair. Transesophageal echocardiography examination can exclude cardiac tamponade and intracardiac source of embolization, and it offers the ability to visualize native or prosthetic valves and assesses their function in the postoperative period. It is helpful in diagnosing endocarditis and the presence of intracardiac masses. In the diagnosis of blunt chest trauma, transesophageal echocardiography offers a fast and safe look at ascending and descending aorta and pericardial effusion, facilitating future decisions about patient management. In patients with postoperative hypoxia, it can exclude intracardiac shunt. Finally, in heart transplants or in managing patients with mechanical heart assist devices, transesophageal echocardiography is an invaluable tool in assessing progress of treatment and complications arising from the procedures. With the introduction of multiplane transesophageal echocardiography probes, technology, and experienced personnel, transesophageal echocardiography becomes the extension of the physical examination in the intensive care unit. This example is one of only a few whereby technology brings the physician closer to the patient.     

Perioperative echocardiographic examination for ventricular assist device implantation

Ventricular assist devices (VADs) are systems for mechanical circulatory support of the patient with severe heart failure. Perioperative transesophageal echocardiography is a major component of patient management, and important for surgical and anesthetic decision making. In this review we present the rationale and available data for a comprehensive echocardiographic assessment of patients receiving a VAD. In addition to the standard examination, device-specific pre-, intra-, and postoperative considerations are essential to the echocardiographic evaluation. These include: (a) the pre-VAD insertion examination of the heart and large vessels to exclude significant aortic regurgitation, tricuspid regurgitation, mitral stenosis, patent foramen ovale, or other cardiac abnormality that could lead to right-to-left shunt after left VAD placement, intracardiac thrombi, ventricular scars, pulmonic regurgitation, pulmonary hypertension, pulmonary embolism, and atherosclerotic disease in the ascending aorta; and to assess right ventricular function; and (b) the post-VAD insertion examination of the device and reassessment of the heart and large vessels. The examination of the device aims to confirm completeness of device and heart deairing, cannulas alignment and patency, and competency of device valves using two-dimensional, and color, continuous and pulsed wave Doppler modalities. The goal for the heart examination after implantation should be to exclude aortic regurgitation, or an uncovered right-to-left shunt; and to assess right ventricular function, left ventricular unloading, and the effect of device settings on global heart function. The variety of VAD models with different basic and operation principles requires specific echocardiographic assessment targeted to the characteristics of the implanted device.     

Circulatory support for fulminant myocarditis: consideration for implantation, weaning and explantation.

OBJECTIVE: Fulminant myocarditis (FM) is an uncommon but life-threatening condition for which a mechanical circulatory support (MCS) device can be life-saving. However, device selection, weaning and explantation procedures remain poorly defined. METHODS: Four patients were bridged to recovery using the Thoratec biventricular support device. All four were in a state of cardiogenic shock with rapid deterioration of their clinical status despite increasing doses of inotropes. Three patients required mechanical respiratory support, three were anuric and one was dialyzed. Echocardiography showed a mean ejection fraction of 12+/-8%. RESULTS: Each Thoratec implantation was performed on cardiopulmonary bypass with a beating heart. Three patients underwent biventricular cannulation. The fourth patient underwent left ventricular and right atrial cannulation. All patients manifested evidence of moderate to severe end organ dysfunction after device implantation. However, by explantation, end organ function had recovered in all patients. After a mean duration of 17+/-10 days, all the patients showed evidence of myocardial recovery. Recovery was confirmed on echocardiography which showed opening of the aortic valve and contraction of both ventricles. The weaning process was performed in 2-5 days by setting the device in a fixed mode and increasing the rate. Device explantation was uneventful in the four patients. At the 6 months echocardiography follow-up, all had normal systolic function. CONCLUSION: In patients with FM, biventricular support allows full circulatory support and unloads both ventricles until recovery occurs. In this set of patients, weaning and removal procedures are straight-forward. These results suggest an aggressive stance toward implantation of MCS in patients with FM.     

Current Strategy for Severe Heart Failure with Mechanical Circulatory Support

Abstract: In the last 10 years, 37 patients received assisted circulation or a ventricular assist device after open-heart operations at the Heart Institute of Japan. After cardiovascular surgery, 12 patients underwent venoarte-rial bypass (VAB), 13 had biventricular bypass (BVB), 8 had left ventricular bypass (LVB), and the remaining 4 received a left ventricular assist device (LVAD). Weaning and discharge rates of the patients by type of circulatory supports were 41.7 and 25.0% with VAB, 69.3 and 46.2% with BVB, 87.5 and 37.5% with LVB, 75.0 and 50.0% with LVAD, and 44.4 and 11.1% with PCPS, respectively. Concerning complications of postcardiotomy circulatory support, hemorrhage and ventricular arrhythmia postcardiotomy circulatory support, hemorrhage, and ventricular arrhythmia (immature weaning) decreased with low-heparinized isolated left ventricular supports (i.e., LVB, LVAD). However, profound biventricular failure, infection, and multiple organ failure remain as possible complications with any type of assisted circulation. These results suggest that early application of circulatory support and appropriate selection of the mode of support and devices used are important for successful circulatory support.     

Intraoperative assessment of cardiac function with transesophageal echocardiography during the Batista operation

We experienced anesthetic management for six cases of the Batista operation and measured cardiac function before and after cardiopulmonary bypass (CPB) with transesophageal echocardiography. In the successful three patients, left ventricle ejection fraction and ejection time were maintained over 25% and 200 msec after CPB, respectively. In the other three resulting in implantation of left ventricular assist device, ejection fraction remained below 20% and ejection time under 200 msec after CPB. Intraoperative transesophageal echocardiography may be useful not only for monitoring of cardiac function but also for the prediction of prognosis.     

Transesophageal echocardiography in renal cell carcinoma: an accurate diagnostic technique for intracaval neoplastic extension

Between 4 and 10% of patients with renal cell carcinoma have tumor involving the inferior vena cava and many of these patients have suprahepatic extension. In patients with intracaval neoplastic extension precise definition of the superior aspect of the tumor thrombus is critical. Transabdominal ultrasonography, computerized tomography (CT), magnetic resonance imaging (MRI) and inferior venacavography are all currently used to evaluate the inferior vena cava in these patients. Intraoperative transesophageal echocardiography was used to image the inferior vena cava in 5 patients with renal cell carcinoma and intracaval neoplastic extension. In each patient transesophageal echocardiography correctly revealed the superior extent of tumor thrombus. In 3 patients tumor thrombus was found at a higher level by transesophageal echocardiography than by CT, MRI and inferior venacavography. In all patients tumor imaging by transesophageal echocardiography correlated well with the gross appearance and extent of tumor found at operation. Echocardiography also documented the absence of residual gross tumor after resection. Transesophageal echocardiography was also useful to assess left ventricular function. Although each of these patients had a pulmonary artery catheter as well transesophageal echocardiography can be useful in situations when right atrial tumor thrombus prevents right heart catheterization. This small series demonstrates that intraoperative transesophageal echocardiography can accurately evaluate the extent of tumor thrombus and provides a means to assess myocardial function complementary to the pulmonary artery catheter.     

经食管超声心动图在心脏手术心肺转流停机困难中的应用进展

由于结构性或功能性心脏异常、血管麻痹综合征或心室功能障碍,心脏外科患者会出现心肺转流（CPB）停机困难。在这些情况下,需要迅速做出决策才能成功停机。自上世纪90年代中期以来,经食管超声心动图（TEE）为评估手术的完整性、识别异常循环状况和指导外科决策提供了帮助。本文分别从心室功能障碍、心脏结构异常、心脏通道功能异常、血管麻痹综合征四个方面分别阐述TEE指导CPB停机困难的应用进展。     

Mechanical circulatory support for the treatment of children with acute fulminant myocarditis

BACKGROUND: Viral myocarditis may follow a rapidly progressive and fatal course in children. Mechanical circulatory support may be a life-saving measure by allowing an interval for return of native ventricular function in the majority of these patients or by providing a bridge to transplantation in the remainder. METHODS: A retrospective chart review of 15 children with viral myocarditis supported with extracorporeal membrane oxygenation (12 patients) or ventricular assist devices (3 patients) was performed. RESULTS: All patients had histories and clinical findings consistent with acute myocarditis. The median age was 4.6 years (range 1 day-13.6 years) with a median duration of mechanical circulatory support of 140 hours (range 48-400 hours). Myocardial biopsy tissue demonstrated inflammatory infiltrates or necrosis, or both, in 8 (67%) of the 12 patients who had biopsies. Overall survival was 12 (80%) of 15 patients, with 10 (83%) survivors of extracorporeal membrane oxygenation and 2 (67%) survivors of ventricular assist device support. Nine (60%) of the 15 patients were weaned from support, with 7 (78%) survivors; the remaining 6 patients were successfully bridged to transplantation, with 5 (83%) survivors. All survivors not undergoing transplantation are currently alive with normal ventricular function after a median follow-up of 1.1 years (range 0.9-5.3 years). CONCLUSION: Eighty-percent of the children who required mechanical circulatory support for acute myocarditis survived in this series. Recovery of native ventricular function to allow weaning from support can be anticipated in many of these patients with excellent prospects for eventual recovery of full myocardial function.     

Bridge to durable left ventricular assist device for refractory cardiogenic shock

Objective

The role of short-term mechanical circulatory support has increased in patients with refractory cardiogenic shock. However, limited data exist on the outcomes of a bridge to a durable left ventricular assist device strategy using short-term mechanical circulatory support.

Progress in perioperative echocardiography: focus on safety, clinical outcomes, 3-dimensional imaging, and education

Gastric decompression with an orogastric tube after anesthetic induction does not appear to enhance image quality for routine cases. The insertion of a transesophageal echocardiographic (TEE) probe can cause significant upper-airway trauma, which can be minimized with rigid laryngoscopy. Limited TEE imaging without transgastric views appears to be safe and clinically adequate in patients with advanced liver disease and esophageal varices. Although esophagogastric perforation because of transesophageal echocardiography is rare, the risk is significantly higher with advanced age and female sex. The echocardiographic assessment of right ventricular function and left ventricular diastolic function can improve the prediction of atrial arrhythmias after elective lung resection. Furthermore, asymptomatic left ventricular systolic or diastolic dysfunction is an independent predictor of cardiovascular mortality and morbidity after open vascular surgery. Advances in 3D echocardiography have shown that hypertrophic cardiomyopathy frequently is associated with changes in the mitral valve complex that predispose to left ventricular outflow tract obstruction. Furthermore, 3D imaging of the mitral apparatus has highlighted the importance of the annular saddle shape and the anatomic variability in ischemic mitral regurgitation. Education in perioperative echocardiography is experiencing high demand that can be satisfied partially with simulators and Internet-based educational activities. These modalities will aid in the dissemination of echocardiography through perioperative practice.     

Reference values for left ventricular function in subjects under general anaesthesia and controlled ventilation assessed by two-dimensional transoesophageal echocardiography

BACKGROUND AND OBJECTIVE: Transoesophageal echocardiography is increasingly used for evaluation and monitoring of left ventricular function in anaesthetized patients. However, the only available reference values for transoesophageal echocardiography were derived from studies in awake subjects. METHODS: We determined left ventricular dimensions and systolic function in 45 patients without clinical evidence of heart disease who voluntarily underwent transesophageal echocardiography under conditions of balanced general anaesthesia, controlled fluid administration, supine position, muscle relaxation and controlled ventilation. RESULTS: The left ventricular dimensions obtained during these conditions were lower than the published normal values in awake subjects. The indices of global left ventricular function, however, were similar to the normal values obtained by either awake transesophageal echocardiography or transthoracic echocardiography. CONCLUSION: We propose using the values obtained in our study as reference values for evaluation of left ventricular function in patients under general anaesthesia and controlled ventilation.     

Mechanical Circulatory Support for Postcardiotomy Ventricular Failure: The Heart Institute of Japan Experience 1984–1992

Abstract: In the last 9 years, 30 patients received assisted circulation or a ventricular assist device after open-heart operations at the Heart Institute of Japan. After cardiovascular surgery, 9 of those patients underwent venoarterial bypass, 10 had biventricular bypass, 7 had left ventricular bypass, and the remaining 4 received a left ventricular assist device. Of the first 15 patients, only 3 (20%) were discharged from the hospital. In contrast, 7 (46.7%) of the last 15 patients were discharged without major complications. With respect to complications, bleeding and ventricular arrhythmia (immature weaning) decreased with low-heparinized isolated left ventricular supports. However, profound biventricular failure, infection, and multiple organ failure remain as possible complications with any type of assisted circulation. These results suggest that early application of circulatory support and appropriate selection of the mode of support and devices used are important for successful circulatory support.     

Improved Results for Postcardiotomy Cardiogenic Shock With the Use of Implantable Left Ventricular Assist Devices

Background. Over the past decade, the use of mechanical circulatory support in patients with postcardiotomy cardiogenic shock has resulted in hospital discharge rates of 25% to 40%. In an attempt to improve patient survival, we initiated a program of early insertion of an implantable Thermocardiosystems Incorporated Heartmate left ventricular assist device in patients who have circulatory failure after having undergone high-risk cardiac operations.

Methods. Between April 1993 and February 1997, 12 patients underwent insertion of an implantable left ventricular assist device for postcardiotomy cardiogenic shock after coronary artery bypass grafting. Indications for insertion included postoperative cardiogenic shock (7 patients), postoperative cardiac arrest (3 patients), and failure to wean from cardiopulmonary bypass (2 patients).

Results. The median time to device insertion was 3.5 days. The mean duration of left ventricular assist device support was 103 ± 19 days (range, 2 to 225 days). Nine of 11 patients (82%) survived to undergo either transplantation (8 patients) or explantation (1 patient), with successful hospital discharge of all 9 patients. The major complication was device-related infection (42%). A single thromboembolism occurred in a patient with an infection.

Conclusions. Long-term outcome after postcardiotomy cardiogenic shock is improved substantially with the use of an implantable left ventricular assist device early in the postoperative course. Access to such a device is an important consideration before undertaking a high-risk cardiac operation, and early implantation of the device is a critical factor in ensuring long-term survival.     

Intraoperative transesophageal echocardiography during surgery for congenital heart defects

OBJECTIVE: This study was undertaken to further define the impact of intraoperative transesophageal echocardiography during surgery for congenital heart disease and to determine appropriate indications. METHODS: The impact of transesophageal echocardiography on patient care was assessed in 1002 patients who underwent this procedure during surgery for congenital heart defects. It had major impact when new information altered the planned procedure or led to a revision of the initial repair. The safety of intraoperative transesophageal echocardiography was evaluated by review of the prospective data sheets and the medical record. A simple relative cost analysis was also performed. RESULTS: Patient median age was 9.9 years (range 2 days to 85 years). Transesophageal echocardiography had prebypass or postbypass major impact in 13.8% of cases (n = 138/1002). Major impact was more frequent during reoperations (P <.03). Procedures that benefited most from the additional information were valve repairs (aortic or atrioventricular) and complex outflow tract reconstructions. Partial anomalous pulmonary venous connection, tricuspid valve repair (other than of Ebstein anomaly), simple atrioventricular discordance, aortic arch anomalies, and secundum atrial septal defects had major impact rates less than 5%. No major complications occurred. Minor complications occurred in 1% of patients and were most often observed in infants smaller than 4 kg. Routine use of transesophageal echocardiography for all patients with congenital heart defects proved cost-effective. CONCLUSIONS: On the combined basis of the observed rates of major impact, the minimal complications, and the relative cost advantage, we believe that routine use of transesophageal echocardiography during most intracardiac repairs of congenital heart defects is justified, particularly for patients undergoing repeat operations for congenital cardiac malformations.     

Assessment of myocardial recovery in a patient with acute myocarditis supported with a left ventricular assist device: a case report.

Acute myocarditis may present with profound hemodynamic compromise; however, spontaneous resolution of the inflammatory process may occur in up to half of such patients. In patients with fulminant myocarditis, mechanical circulatory support may serve as a bridge to myocardial recovery. In this report we describe a 35-year-old man with acute myocarditis who required left ventricular assist device support as a bridge to recovery, and suggest a method for determining the suitability and timing of device explantation. A combination of echocardiography, right heart catheterization, exercise testing and serial endomyocardial biopsies was used to determine the resolution of myocarditis, recovery of myocardial function and timing for device explantation. Successful device explantation was performed after 37 days of device support. Further study is required to assess the role of ventricular assist devices in combination with immunosuppressive therapy in the management of fulminant myocarditis.     

Anesthetic management of thrombectomy for left ventricular huge mobile thrombus

A 45 year-old male underwent thrombectomy for huge mobile thrombus and aneurysmectomy in the left ventricle. Despite of the patient's preoperative poor cardiac function and difficulties in weaning from cardiopulmonary bypass, he could recover with the aid of left ventricular bypass for 6 days without complications such as thromboembolism. Intraoperative transesophageal echocardiography was useful in observation of thrombus, decision making in the adaptation and type-selection of mechanical ventricular support, and evaluation of its efficacy.     

Anesthetic management for pneumonectomy in a patient with cardiac amyloidosis

Cardiac amyloidosis may cause restrictive cardiomyopathy associated with heart failure, conduction disorder and ischemic heart disease. Therefore, patients with amyloidosis require careful hemodynamic monitoring in perioperative period. A 63-year-old man with cardiac amyloidosis was scheduled for pneumonectomy. His transthoracic echocardiography assessment showed a hypertrophic interventricular septum and slight decreased ejection fraction of 55%, but left ventricular (LV) diastolic function was decreased. Pulse Doppler for mitral valve inflow showed that the early peak velocity/atrial peak velocity (E/A) ratio was 0.9, the deceleration time (DT) was 163 msec and the early diastolic mitral annular tissue velocity (E') was 4 cm x sec(-1). These data suggested a pseudonormalization state. We performed careful monitoring using arterial pressure-based cardiac output (APCO), central venous oxygen saturation (ScvO2) and transesophageal echocardiography. There were no severe complications such as circulatory collapse and arrhythmia in the perioperative period.