Frank W. Dupont

Real-Time Three-Dimensional Transesophageal Echocardiography in Valve Disease: Comparison With Surgical Findings and Evaluation of Prosthetic Valves

BACKGROUND Recently, a novel real-time 3-dimensional (3D) matrix-array transesophageal echocardiographic (3D-MTEE) probe was found to be highly effective in the evaluation of native mitral valves (MVs) and other intracardiac structures, including the interatrial septum and left atrial appendage. However, the ability to visualize prosthetic valves using this transducer has not been evaluated. Moreover, the diagnostic accuracy of this new technology has never been validated against surgical findings. This study was designed to (1) assess the quality of 3D-MTEE images of prosthetic valves and (2) determine the potential value of 3D-MTEE imaging in the preoperative assessment of valvular pathology by comparing images with surgical findings. METHODS Eighty-seven patients undergoing clinically indicated transesophageal echocardiography were studied. In 40 patients, 3D-MTEE images of prosthetic MVs, aortic valves (AVs), and tricuspid valves (TVs) were scored for the quality of visualization. For both MVs and AVs, mechanical and bioprosthetic valves, the rings and leaflets were scored individually. In 47 additional patients, intraoperative 3D-MTEE diagnoses of MV pathology obtained before initiating cardiopulmonary bypass were compared with surgical findings. RESULTS For the visualization of prosthetic MVs and annuloplasty rings, quality was superior compared with AV and TV prostheses. In addition, 3D-MTEE imaging had 96% agreement with surgical findings. CONCLUSIONS Three-dimensional matrix-array transesophageal echocardiographic imaging provides superb imaging and accurate presurgical evaluation of native MV pathology and prostheses. However, the current technology is less accurate for the clinical assessment of AVs and TVs. Fast acquisition and immediate online display will make this the modality of choice for MV surgical planning and postsurgical follow-up.

Changes in Regional Myocardial Function after Coronary Artery Bypass Graft Surgery Are Predicted by Intraoperative Low-dose Dobutamine Echocardiography

BACKGROUND Left ventricular dysfunction is often reversed after coronary artery bypass graft (CABG) surgery; however, this change is not easily predicted. The authors hypothesized that functional changes after a low dose of dobutamine (5 microgram. kg-1. min-1) intraoperatively would predict functional changes when complete revascularization was achieved. METHODS The authors analyzed 560 segments in 40 patients scheduled for elective CABG surgery for regional wall motion (1-5 scoring system) at four stages: baseline (after induction and intubation), with administration of low-dose dobutamine before cardiopulmonary bypass, after separation from cardiopulmonary bypass (early), and after administration of protamine (late). Two independent observers scored the myocardial regions according to a 16-segment model in multiple imaging planes. For each segment, the response to dobutamine was dichotomized as improved or not improved from baseline and analyzed with logistic regression. The influence of covariates (ejection fraction, myocardial infarction, diabetes mellitus, and beta blockers) was also determined with logistic regression models. P < 0.05 was considered significant. RESULTS Changes in myocardial function after low-dose dobutamine were highly predictive for early (P < 0.0001) and late (P < 0.0001) changes in myocardial function from baseline regional scores. The overall odds ratio for early and late improvement increased by 20.7 and 34.6, respectively, when improvement was observed after low-dose dobutamine was administered. The overall positive predictive value of improved regional wall motion after CABG did not vary with left ventricular ejection fraction, a history of myocardial infarction, or beta blocker use, and it varied little with diabetic status (range, 0.86-0.96) if regional wall motion improved with low-dose dobutamine before CABG. The overall negative predictive value was 0.70; however, the range varied with diabetic status (i.e., lowest in diabetic patients and highest in nondiabetic patients). CONCLUSION Intraoperative low-dose dobutamine is a reliable method to predict myocardial functional reserve and to determine functional recovery expected after coronary revascularization.

Methoxyisobutylisonitrile (MIBI) Tc 99m SPECT to establish a correlate to coronary flow reserve, the perfusion reserve, from global and regional myocardial uptake after exercise and rest

With99mTc-MIBI SPECT and a 4 h exercise (E; 150 MBq iv) and rest (R; 800 MBq iv) protocol global and regional left ventricular (LV) myocardial uptake was determined in 70 patients with angiographicall, confirmed coronary heart disease (CHD) and in 10 controls. The aim was to establish an E/R ratio as a correlate to coronary vascular reserve, representing perfusion reserve (PR). E/R ratios, obtained from total LV myocardium or from normal or impaired regions, were > 1.19 under all conditions, indicating the presence of higher flow during exercise than at rest (even in areas of low flow). Global PR separated (P<0.01) controls (1.63±0.21; mean ± SD) from severely diseased patients (1.29 ±0.14 in 2- or 3-vessel disease) only. Improved differential diagnosis was gained from calibrating the regional E/R ratio to regional differences (E minus R) of uptake. For the left ventricle regional PRs (RPR) for 25 ROIs of the target, framing the myocardium, were determined RPR at the regional maximum of99mTc-MIBI uptake was similar in both controls (1.66) and patients (1.63), indicating a high probability of meeting some areas with functionally normal perfusion in patients with CHD. RPR allowed sufficient separation (P<0.025) concerning the degree of coronary artery stenosis (RPR in occlusion, 0.26; stenosis >75%, 0.39; <75%, 0.56). In controls, the overall value for RPR was 1.14+0.28 (P< 0.001). LV global PR and RPR were useful in separating patients with CHD vs controls and in classifying the severity of vascular stenosis.

Is there a long-term predictive value of intraoperative low-dose dobutamine echocardiography in patients who have coronary artery bypass graft surgery with cardiopulmonary bypass?

UNLABELLED In patients with coronary artery disease, chronic regional left ventricular systolic dysfunction at rest may be caused by hibernating or by infarcted myocardium. Intraoperative low-dose dobutamine (LDD) echocardiography reliably predicts the immediate recovery of regional myocardial function after coronary artery bypass graft (CABG) surgery. We sought to determine whether intraoperative LDD echocardiography would also predict recovery of regional function after 1 yr. Twenty-five patients with coronary artery disease who underwent CABG surgery with intraoperative LDD echocardiography were evaluated 1 yr later with a follow-up transthoracic echocardiogram. The covariates of left ventricular ejection fraction, old myocardial infarction, and diabetes mellitus were considered in an analysis of regional wall motion (RWM). A 16-segment model and a 1-5-point scoring system were used to evaluate 350 myocardial segments. Multiple logistic regression analysis was performed to determine whether response to intraoperative LDD echocardiography (5 microg. kg(-1). min(-1)) predicted changes in regional function at 1 yr. A segment was defined as stunned if the RWM score obtained during LDD infusion deteriorated after cardiopulmonary bypass but recovered in the 1-yr follow-up echocardiogram. A response to intraoperative LDD predicted changes in regional function at 1 yr. The overall odds of improvement in regional function were 2.22 times greater (95% confidence interval = 1.29, 3.82; P = 0.0039) with a positive response to intraoperative LDD. The positive predictive value of intraoperative LDD echocardiography for improvement in myocardial function was 0.81 and the negative predictive value was 0.34. The predictive values did not vary with the examined covariates. Of segments with unexpected deterioration of RWM immediately after cardiopulmonary bypass, 87% recovered at the time of the 1-yr follow-up echocardiogram. Contractile reserve demonstrated by intraoperative LDD echocardiography predicts regional function at 1 yr; however, the test cannot predict which segment will not recover. Most of unexpected regional ventricular systolic dysfunction immediately after CABG surgery can be attributed to myocardial stunning. IMPLICATIONS In patients undergoing coronary artery bypass graft surgery, intraoperative low-dose dobutamine echocardiography has only limited value for the prediction of regional myocardial function at 1 yr. Small-dose dobutamine echocardiography predicts regional myocardial function at 1 yr when baseline regional wall motion abnormalities improve with dobutamine; however, the test cannot be used to predict which segment will not recover at 1 yr.

Anesthesia for Esophageal Surgery

Esophageal surgery comprises a variety of procedures of differing complexity to treat functional and structural disorders of the esophagus. Local disease extension, surgical repair technique, and physical status of the patient primarily dictate anesthetic management of patients with esophageal pathology. Because the esophagus is in close proximity to vital organs and structures, a specific knowledge of the anatomy is essential to realize how esophageal pathology can compromise elemental physiological functions. A com prehensive anesthetic plan requires a detailed under standing of the surgical procedure in terms of approach, the extent of the operation, and associated complica tions. Consideration of comorbid conditions is equally important, as esophageal surgery is frequently per formed in debilitated and polytraumatized patients. The following article will review clinical manifestation, surgi cal therapy, and perioperative anesthetic management of the most commonly encountered esophageal disor ders. Specifically, anesthetic considerations in gastro esophageal reflux disease, esophageal carcinoma, esophageal perforation, and a variety of other esopha geal disorders will be discussed.

CASE 2—2016 Complete Failure of Mechanical Mitral Valve Opening on Weaning From Cardiopulmonary Bypass

From the *Department of Anesthesiology, Rush University Medical Center, Chicago, IL; †Department of Anesthesia and Critical Care, University of Chicago Medical Center, Chicago, IL; ‡Hospital of the University of Pennsylvania, Philadelphia, PA; and §Department of Anesthesiology Montefiore Medical Center, Bronx, NY. Address reprint requests to Kimberly L. Kesner, MD, Department of Anesthesiology, Rush University Medical Center, 1653 W. Congress Parkway, #739, Chicago, IL 60637. E-mail: kim.taub@gmail.com