Publications

OBJECTIVE: To demonstrate the clinical feasibility of accurately measuring tricuspid annular area by 3-dimensional (3D) transesophageal echocardiography (TEE) and to assess the geometric differences based on the presence of tricuspid regurgitation (TR). Also, the shape of the tricuspid annulus was compared with previous descriptions in the literature.

DESIGN: Prospective.

SETTING: Tertiary care university hospital.

INTERVENTIONS: Three-dimensional TEE.

PARTICIPANTS: Patients undergoing cardiac surgery.

MEASUREMENTS AND MAIN RESULTS: Volumetric data sets from 20 patients were acquired by 3D TEE and prospectively analyzed. Comparisons in annular geometry were made between groups based on the presence of TR. The QLab (Philips Medical Systems, Andover, MA) software package was used to calculate tricuspid annular area by both linear elliptical dimensions and planimetry. Further analyses were performed in the 4D Cardio-View (TomTec Corporation GmBH, Munich, Germany) and MATLAB (Natick, MA) software environments to accurately assess annular shape. It was found that patients with greater TR had an eccentrically dilated annulus with a larger annular area. Also, the area as measured by the linear ellipse method was overestimated as compared to the planimetry method. Furthermore, the irregular saddle-shaped geometry of the tricuspid annulus was confirmed through the mathematic model developed by the authors.

CONCLUSIONS: Three-dimensional TEE can be used to measure the tricuspid annular area in a clinically feasible fashion, with an eccentric dilation seen in patients with TR. The tricuspid annulus shape is complex, with annular high and low points, and annular area calculation based on linear measurements significantly overestimates 3D planimetered area.

With the resurgence in popularity of aortic valve (AV) repair, detailed anatomical information of the AV has become invaluable for surgical decision making as well as for evaluation of success postrepair. Perioperative 3-dimensional echocardiography is optimally suited to assist in repair planning. The volumetric nature of the 3-dimensional data allows accurate derivation of qualitative and quantitative measurements. A uniform approach to imaging and description of echocardiographic AV anatomy is essential to facilitate communication across specialties.

PURPOSE: The purpose of this review was to evaluate new computer software available for 3-dimensional right ventricular (RV) volume estimation.

DESCRIPTION: Based on 2-dimensional echocardiography, various algorithms have been used for RV volume estimation. These are complex, time-consuming techniques and are prone to significant error. The current clinical paradigm of RV volume assessment is based on the visual quantitative assessment of chamber size and the use of tricuspid annular and RV internal diameters as a surrogate measure of RV volume. Hence, there is a need for a practical method for the intraoperative assessment of RV volume.

EVALUATION: The evaluation consists of an objective review of the capabilities of this software and its potential application in the operating room. The authors also performed a detailed review of the potential limitations and possible improvements.

CONCLUSIONS: This new software has the potential to be incorporated into the existing workflow environment of the ultrasound systems in the future, making it clinically feasible to perform perioperative RV volume analysis.

OBJECTIVE: To highlight the limitations of traditional 2-dimensional (2D) echocardiographic mitral valve (MV) examination methodologies, which do not account for patient-specific transesophageal echocardiographic (TEE) probe adjustments made during an actual clinical perioperative TEE examination.

DESIGN: Institutional quality-improvement project.

SETTING: Tertiary care hospital.

PARTICIPANTS: Attending anesthesiologists certified by the National Board of Echocardiography.

INTERVENTION: Using the technique of multiplanar reformatting with 3-dimensional (3D) data, ambiguous 2D images of the MV were generated, which resembled standard midesophageal 2D views. Based on the 3D image, the MV scallops visualized in each 2D image were recognized exactly by the position of the scan plane. Twenty-three such 2D MV images were created in a presentation from the 3D datasets. Anesthesia staff members (n = 13) were invited to view the presentation based on the 2D images only and asked to identify the MV scallops. Their responses were scored as correct or incorrect based on the 3D image.

METHODS AND MAIN RESULTS: The overall accuracy was 30.4% in identifying the MV scallops. The transcommissural view was identified correctly >90% of the time. The accuracy of the identification of A1, A3, P1, and P3 scallops was <50%. The accuracy of the identification of A2P2 scallops was ≥50%.

CONCLUSION: In the absence of information on TEE probe adjustments performed to acquire a specific MV image, it is possible to misidentify the scallops.

Pharmacologically induced angiogenesis could be a promising option in clinical situations with diffuse inoperable coronary artery disease e.g. metabolic syndrome and diabetes mellitus. The failure of focused cytokine, stem cell and gene therapies to achieve both perfusion and functional improvement in clinical trials suggests a more centralized control mechanism. Neuropeptide-Y (NPY) is one such natural neurotransmitter that is known to exert a multifaceted role during neo-angiogenesis and can possibly act as the central control. To date, the ability to harness the 'master switch' nature of NPY in a specific experimental model of metabolic syndrome and chronic myocardial ischemia has not been conclusively demonstrated. We hypothesized that infiltration of NPY into an area of chronic ischemia in a metabolic syndrome swine model would induce angiogenesis and improve myocardial perfusion and function. An osmotic pump was inserted three weeks after surgical induction of focal myocardial ischemia. We delivered either NPY or placebo for five weeks, after which the myocardial tissue was harvested for analysis. Assessments of myocardial perfusion and function were performed at each stage of the experiment. Local infiltration of NPY significantly improved collateral vessel formation, blood flow and myocardial function. We believe activation of NPY receptors may be a potential target therapy for patients with diffuse coronary artery disease.

OBJECTIVES: To investigate the effects of acute elevation in afterload on global (systolic and diastolic) myocardial function by performing serial intraoperative transesophageal echocardiograms during and after cross-clamp application on patients undergoing elective abdominal aortic aneurysm (AAA) surgery.

DESIGN: A prospective observational study.

SETTING: A tertiary care university hospital.

PARTICIPANTS: Patients undergoing elective AAA repair under general anesthesia (GA).

INTERVENTION: The use of perioperative transesophageal echocardiography to calculate a tissue Doppler-derived myocardial performance index (MPI) during different stages of the surgery.

MEASUREMENT AND RESULTS: Twenty consecutive patients scheduled for suprarenal AAA repair under GA were included in the study. Perioperative transesophageal echocardiography was performed after the induction of GA. MPI was calculated with Doppler tissue imaging as the sum of isovolumetric contraction and relaxation times divided by the ejection time before cross-clamping of the aorta and then 2, 10, and 20 minutes after cross-clamp application. A final MPI was measured after unclamping of the aorta. As compared with baseline, cross-clamp application initially worsened MPI within 2 minutes and then MPI improved to baseline after 10 minutes of cross-clamp application. The MPI improved significantly after unclamping of the aorta.

CONCLUSIONS: The authors observed a temporal variation in global myocardial function after the application of a cross-clamp in the suprarenal position. There was transient deterioration of global myocardial function (the prolongation of MPI) 2 minutes after cross-clamp application, which improved within 10 minutes. Myocardial function returned to baseline after unclamping the aorta.

The Doppler assessment of diastolic dysfunction (DD) is not part of a standard comprehensive intraoperative echocardiographic examination. Although the reasons may be many, the lack of a simplified algorithm for the assessment of DD specific to the perioperative arena, the implications of this diagnosis on clinical care, and the absence of therapeutic options are some of the commonly cited reasons. In this article, the authors address these possible reasons for the lack of routine application of Doppler indices to assess perioperative DD. The authors have chosen to highlight some of the most common conceptual questions, which often have been raised by anesthesiologists, and attempted to suggest answers. Drawing from their experience and data, the authors propose a simplified algorithm for the application of Doppler to assess and diagnose DD with an individualized and a mechanistic approach. The proposed algorithm is from within the premise of the published guidelines and attempts to simplify the perioperative approach. The authors hope this approach will be simple enough for routine application to affect therapy and a tangible change in outcome. The authors suggest that knowledge of left atrial size is valuable as a marker for persistently increased left ventricular end-diastolic pressure and its possible role in risk stratification.

Assessment of diastolic function should be a component of a comprehensive perioperative transesophageal echocardiographic examination. Abnormal diastolic function exists in >50% of patients presenting for cardiac and high-risk noncardiac surgery, and has been shown to be an independent predictor of adverse postoperative outcome. Normalcy of systolic function in 50% of patients with congestive heart failure implicates diastolic dysfunction as the probable etiology. Comprehensive evaluation of diastolic function requires the use of various, load-dependent Doppler techniques This is further complicated by the additional effects of dehydration and anesthetic drugs on myocardial relaxation and compliance as assessed by these Doppler measures. The availability of more sophisticated Doppler techniques, e.g., Doppler tissue imaging and flow propagation velocity, makes it possible to interrogate left ventricular diastolic function with greater precision, analyze specific stages of diastole, and to differentiate abnormalities of relaxation from compliance. Additionally, various Doppler-derived ratios can be used to estimate left ventricular filling pressures. The varying hemodynamic environment of the operating room mandates modification of the diagnostic algorithms used for ambulatory cardiac patients when left ventricular diastolic function is evaluated with transesophageal echocardiography in anesthetized surgical patients.