Robina Matyal

Continuous perioperative insulin infusion decreases major cardiovascular events in patients undergoing vascular surgery: a prospective, randomized trial.

Background:A growing body of evidence suggests that hyperglycemia is an independent predictor of increased cardiovascular risk. Aggressive glycemic control in the intensive care decreases mortality. The benefit of glycemic control in noncardiac surgery is unknown. Methods:In a single-center, prospective, unblinded, active-control study, 236 patients were randomly assigned to continuous insulin infusion (target glucose 100–150 mg/dl) or to a standard intermittent insulin bolus (treat glucose > 150 mg/dl) in patients undergoing peripheral vascular bypass, abdominal aortic aneurysm repair, or below- or above-knee amputation. The treatments began at the start of surgery and continued for 48 h. The primary endpoint was a composite of all-cause death, myocardial infarction, and acute congestive heart failure. The secondary endpoints were blood glucose concentrations, rates of hypoglycemia (< 60 mg/dl) and hyperglycemia (> 150 mg/dl), graft failure or reintervention, wound infection, acute renal insufficiency, and duration of stay. Results:The groups were well balanced for baseline characteristics, except for older age in the intervention group. There was a significant reduction in primary endpoint (3.5%) in the intervention group compared with the control group (12.3%) (relative risk, 0.29; 95% confidence interval, 0.10–0.83; P = 0.013). The secondary endpoints were similar. Hypoglycemia occurred in 8.8% of the intervention group compared with 4.1% of the control group (P = 0.14). Multivariate analysis demonstrated that continuous insulin infusion was a negative independent predictor (odds ratio, 0.28; 95% confidence interval, 0.09–0.87; P = 0.027), whereas previous coronary artery disease was a positive predictor of adverse events. Conclusion:Continuous insulin infusion reduces perioperative myocardial infarction after vascular surgery.

Utility of a transesophageal echocardiographic simulator as a teaching tool.

OBJECTIVE This study was designed to test the hypothesis that simulator-based transesophageal echocardiographic training was a more effective method of training anesthesia residents with no prior experience in echocardiography as compared with conventional methods of training (books, articles, and web-based resources). STUDY DESIGN A prospective randomized study. SETTING An academic medical center (teaching hospital). PARTICIPANTS The participants consisted of first-year anesthesia residents. INTERVENTION The study design was composed of 2 groups: a control group (group 1, conventional group) and a study group (group 2, simulator group). The residents belonging to group 2 (simulator group) received a 90-minute simulator-based teaching session moderated by a faculty experienced in transesophageal echocardiography. Residents belonging to group 1 (conventional group) were asked to review the guidelines of the comprehensive intraoperative transesophageal echocardiographic examination published by the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. They also were encouraged to use other learning resources (eg, textbooks, electronic media, and web-based resources) to understand the underlying concepts of echocardiography. Written pre- and post-test was administered to both groups. MEASUREMENTS AND MAIN RESULTS The groups were compared for the pretest scores by the nonparametric Mann-Whitney U test. Pre- and post-test scores were compared with a Wilcoxon paired test in the individual groups. The results showed a statistically significant difference between the scores of the 2 groups with better scores in the simulation group in the post-training test. CONCLUSION The simulator-based teaching model for transesophageal echocardiography is a better method of teaching the basic concepts of transesophageal echocardiography like anatomic correlation, structure identification, and image acquisition.

Perioperative diastolic dysfunction during vascular surgery and its association with postoperative outcome

OBJECTIVE To assess the association of perioperative cardiac dysfunction during elective vascular surgery with postoperative outcome. BACKGROUND Patients with normal systolic function can have isolated diastolic dysfunction. Routine preoperative evaluation of left ventricular (LV) function does not include an assessment of diastolic function for risk stratification. We hypothesized that perioperative assessment of both diastolic and systolic function with transesophageal echo (TEE) may improve our ability to predict postoperative outcome. METHODS Perioperative TEE examinations were carried out on patients undergoing elective vascular surgery under general anesthesia. Abnormal systolic function was defined as LV ejection fraction (LVEF) <40%. Left ventricular diastolic function was assessed using transmitral flow propagation velocity (Vp); Vp <45 cm/sec was considered abnormal. We determined the association between LV function and the primary outcome of postoperative adverse outcome, defined as one or more adverse events: myocardial infarction (MI), congestive heart failure (CHF), significant arrhythmia, prolonged intubation, renal failure, and death. RESULTS Three hundred thirteen patients undergoing vascular surgery were studied. We found that 8% (n = 24) of patients had isolated systolic dysfunction, 43% (n = 134) had isolated diastolic dysfunction, and 24% (n = 75) both systolic and diastolic dysfunction. The most common postoperative adverse outcome was CHF 20% (n = 62). By multivariate logistic regression, we found that patient age, Vp, type of surgery, female gender, and renal failure were predictive of postoperative adverse outcome. CONCLUSION The presence of perioperative diastolic dysfunction as assessed with Vp is an independent predictor of postoperative CHF and prolonged length of stay after major vascular surgery. Patient age, gender, type of surgery, and renal failure were also predictors of outcome. Perioperative systolic function was not a predictor of postoperative outcome in our patients.

Relative importance of aneurysm diameter and body size for predicting abdominal aortic aneurysm rupture in men and women

OBJECTIVE Women have been shown to have up to a fourfold higher risk of abdominal aortic aneurysm (AAA) rupture at any given aneurysm diameter compared with men, leading to recommendations to offer repair to women at lower diameter thresholds. Although this higher risk of rupture may simply reflect greater relative aortic dilatation in women who have smaller aortas to begin with, this has never been quantified. Our objective was therefore to quantify the relationship between rupture and aneurysm diameter relative to body size and determine whether a differential association between aneurysm diameter, body size, and rupture risk exists for men and women. METHODS We performed a retrospective review of all patients in the Vascular Study Group of New England (VSGNE) database who underwent endovascular or open AAA repair. Height and weight were used to calculate each patients body mass index and body surface area (BSA). Next, indices of each measure of body size (height, weight, body mass index, BSA) relative to aneurysm diameter were calculated for each patient. To generate these indices, we divided aneurysm diameter (in cm) by the measure of body size; for example, aortic size index (ASI) = aneurysm diameter (cm)/BSA (m(2)). Along with other relevant clinical variables, we used these indices to construct different age-adjusted and multivariable-adjusted logistic regression models to determine predictors of ruptured repair vs elective repair. Models for men and women were developed separately, and different models were compared using the area under the curve. RESULTS We identified 4045 patients (78% male) who underwent AAA repair (53% endovascular aortic aneurysm repairs). Women had significantly smaller diameter aneurysms, lower BSA, and higher BSA indices than men. For men, the variable that increased the odds of rupture the most was aneurysm diameter (area under the curve = 0.82). Men exhibited an increased rupture risk with increasing aneurysm diameter (<5.5 cm: odds ratio [OR], 1.0; 5.5-6.4 cm: OR, 0.9; 95% confidence interval [CI], 0.5-1.7; P = .771; 6.5-7.4 cm: OR, 3.9; 95% CI, 1.9-1.0; P < .001; ≥ 7.5 cm: OR, 11.3; 95% CI, 4.9-25.8; P < .001). In contrast, the variable most predictive of rupture in women was ASI (area under the curve = 0.81), with higher odds of rupture at a higher ASI (ASI >3.5-3.9: OR, 6.4; 95% CI, 1.7-24.1; P = .006; ASI ≥ 4.0: OR, 9.5; 95% CI, 2.3-39.4; P = .002). For women, aneurysm diameter was not a significant predictor of rupture after adjusting for ASI. CONCLUSIONS Aneurysm diameter indexed to body size is the most important determinant of rupture for women, whereas aneurysm diameter alone is most predictive of rupture for men. Women with the largest diameter aneurysms and the smallest body sizes are at the greatest risk of rupture.

Presentation, treatment, and outcome differences between men and women undergoing revascularization or amputation for lower extremity peripheral arterial disease

OBJECTIVE Prior studies have suggested treatment and outcome disparities between men and women for lower extremity peripheral arterial disease after surgical bypass. Given the recent shift toward endovascular therapy, which has increasingly been used to treat claudication, we sought to analyze sex disparities in presentation, revascularization, amputation, and inpatient mortality. METHODS We identified individuals with intermittent claudication and critical limb ischemia (CLI) using International Classification of Diseases, Ninth Revision codes in the Nationwide Inpatient Sample from 1998 to 2009. We compared presentation at time of intervention (intermittent claudication vs CLI), procedure (open surgery vs percutaneous transluminal angioplasty or stenting vs major amputation), and in-hospital mortality for men and women. Regional and ambulatory trends were evaluated by performing a separate analysis of the State Inpatient and Ambulatory Surgery Databases from four geographically diverse states: California, Florida, Maryland, and New Jersey. RESULTS From the Nationwide Inpatient Sample, we identified 1,797,885 patients (56% male) with intermittent claudication (26%) and CLI (74%), who underwent 1,865,999 procedures (41% open surgery, 20% percutaneous transluminal angioplasty or stenting, and 24% amputation). Women were older at the time of intervention by 3.5 years on average and more likely to present with CLI (75.9% vs 72.3%; odds ratio [OR], 1.21; 95% confidence interval [CI], 1.21-1.23; P < .01). Women were more likely to undergo endovascular procedures for both intermittent claudication (47% vs 41%; OR, 1.27; 95% CI, 1.25-1.28; P < .01) and CLI (21% vs 19%; OR, 1.14; 95% CI, 1.13-1.15; P < .01). From 1998 to 2009, major amputations declined from 18 to 11 per 100,000 in men and 16 to 7 per 100,000 in women, predating an increase in total CLI revascularization procedures that was seen starting in 2005 for both men and women. In-hospital mortality was higher in women regardless of disease severity or procedure performed even after adjusting for age and baseline comorbidities (.5% vs .2% after percutaneous transluminal angioplasty or stenting for intermittent claudication; 1.0% vs .7% after open surgery for intermittent claudication; 2.3% vs 1.6% after percutaneous transluminal angioplasty or stenting for CLI; 2.7% vs 2.2% after open surgery for CLI; P < .01 for all comparisons). CONCLUSIONS There appears to be a preference to perform endovascular over surgical revascularization among women, who are older and have more advanced disease at presentation. Percutaneous transluminal angioplasty or stenting continues to be popular and is increasingly being performed in the outpatient setting. Amputation and in-hospital mortality rates have been declining, and women now have lower amputation but higher mortality rates than men. Recent improvements in outcomes are likely the result of a combination of improved medical management and risk factor reduction.

Transesophageal Echocardiography Simulator: A New Learning Tool

RANSESOPHAGEAL ECHOCARDIOGRAPHY (TEE)is a minimally invasive monitoring modality. The initialuse of TEE was limited to the acquisition of images in patientswith suboptimal echo windows during transthoracic echocar-diography. Its role has exponentially expanded to become al-most a standard of care during cardiac surgery and a valuableprocedural adjunct.

Transesophageal Echocardiography and Noncardiac Surgery

The use of transesophageal echocardiography (TEE) for monitoring during cardiac and noncardiac surgery has increased exponentially over the past few decades. TEE has evolved from a diagnostic tool to a monitoring device and a procedural adjunct. The close proximity of the TEE transducer to the heart generates high-quality images of the intracardiac structures and their spatial orientation. The use of TEE in noncardiac and critical care settings is not well studied, and the evidence of the benefits of its use in these settings is lacking. Despite the widespread availability of TEE equipment in US hospitals, less than 30% of anesthesiologists are formally trained in the use of perioperative TEE. In this review, the safety and indications of TEE are reviewed and detailed analysis of the best available evidence in this regard is presented. Landmark trials evaluating the use of TEE and its therapeutic impact in noncardiac surgical setting are critically reviewed. This article details recommendations to familiarize anesthesiologists with TEE technology to exploit it to its fullest potential to achieve better patient monitoring standards and eventually improve outcome. Training of greater numbers of anesthesiologists in TEE is needed to increase awareness of the indications and contraindications. Until relatively inexpensive TEE equipment is available, the initial cost of equipment acquisition remains a significant prohibitive factor limiting its widespread use.

Three-Dimensional Printing of Mitral Valve Using Echocardiographic Data

Three-dimensional (3D) printing has steadily gained traction as a clinical tool. Current applications include developing patient-specific implants, prostheses, and realistic anatomic models for surgical education and planning [(1,2)][1]. In cardiac surgery, patient-specific 3D models of hearts with

Dynamic 3-Dimensional Echocardiographic Assessment of Mitral Annular Geometry in Patients With Functional Mitral Regurgitation

BACKGROUND Mitral valve (MV) annular dynamics have been well described in animal models of functional mitral regurgitation (FMR). Despite this, little if any data exist regarding the dynamic MV annular geometry in humans with FMR. In the current study we hypothesized that 3-dimensional (3D) echocardiography, in conjunction with commercially available software, could be used to quantify the dynamic changes in MV annular geometry associated with FMR. METHODS Intraoperative 3D transesophageal echocardiographic data obtained from 34 patients with FMR and 15 controls undergoing cardiac operations were dynamically analyzed for differences in mitral annular geometry with TomTec 4D MV Assessment 2.0 software (TomTec Imaging Systems GmbH, Munich, Germany). RESULTS In patients with FMR, the mean mitral annular area (14.6 cm(2) versus 9.6 cm(2)), circumference (14.1 cm versus 11.4 cm), anteroposterior (4.0 cm versus 3.0 cm) and anterolateral-posteromedial (4.3 cm versus 3.6 cm) diameters, tenting volume (6.2 mm(3) versus 3.5 mm(3)) and nonplanarity angle (NPA) (154 degrees ± 15 versus 136 degrees ± 11) were greater at all points during systole compared with controls (p < 0.01). Vertical mitral annular displacement (5.8 mm versus 8.3 mm) was reduced in FMR compared with controls (p < 0.01). CONCLUSIONS There are significant differences in dynamic mitral annular geometry between patients with FMR and those without. We were able to analyze these changes in a clinically feasible fashion. Ready availability of this information has the potential to aid comprehensive quantification of mitral annular function and possibly assist in both clinical decision making and annuloplasty ring selection.

Perioperative assessment of diastolic dysfunction.

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.