Echocardiographic Assessment of the Mitral Valve for Suitability of Repair: An Intraoperative Approach From a Mitral Center

Intraoperative echocardiography of the mitral valve in the precardiopulmonary bypass period is an integral part of the surgical decision-making process for assessment of suitability for repair. Although there are comprehensive reviews in the literature regarding echocardiographic examination of the mitral valve, the authors present a practical stepwise algorithmic workflow to make objective recommendations. Advances in echocardiography allow for quantitative geometric analyses of the mitral valve, along with precise assessment of the valvular apparatus with three-dimensional echocardiography. In the precardiopulmonary bypass period, echocardiographers are required to diagnose and quantify valvular dysfunction, assess suitability for repair, assist in annuloplasty ring sizing, and determine the success or failure of the surgical procedure. In this manuscript the authors outline an algorithmic approach to intraoperative echocardiography examination using two-dimensional and three-dimensional modalities to objectively analyze mitral valve function and assist in surgical decision-making.

Three-Dimensional Transesophageal Echocardiography Simulator: New Learning Tool for Advanced Imaging Techniques

The use of intraoperative three-dimensional (3D) transesophageal echocardiography (TEE) has grown exponentially in recent years. Three-dimensional TEE technology has evolved to allow for real-time display of 3D images and, thus, has become the standard of care for the evaluation of cardiac anatomy and function. Its use has provided a new dimension of clinical insight when managing patients for cardiac surgery or structural heart interventions. While the intraoperative utility of 3D TEE has expanded, there has been a slower advancement in the area of training and, specifically, simulator-based training in 3D TEE. This training is essential, as the skill set involved in acquiring 3D data sets differs from that of two-dimensional (2D) TEE and requires users to be able to appreciate how 3D anatomic display differs from that of tomographic cross-sectional 2D imaging. This added skill set requires mental reconstruction and spatial reorientation to appreciate the added elevational dimension in frustum-based imaging and is best achieved in a simulation environment rather than the busy operating room. In this review article, the authors evaluate the functionality of a 3D TEE simulator and how simulators such as this can establish preclinical proficiency in novices in the expanding area of advanced 3D TEE imaging.

Enhanced Post-Operative Recovery with Continuous Peripheral Nerve Block After Lower Extremity Amputation

BACKGROUND

Despite progress in perioperative care standards, there has not been a significant risk reduction in morbidity and mortality rates of lower extremity amputations, an intermediate risk surgery performed on high risk patients. The single-shot peripheral nerve block has shown equivocal impact on postoperative course following lower extremity amputation. Hence, we assessed the potential of preemptive use of continuous catheter-based peripheral nerve block in lower extremity amputations for reduction in pulmonary complications, acute post-operative pain scores, and opioid use in post-operative period.

METHODS

A retrospective review of a quality improvement project initiated in 2018 was conducted to compare outcomes amongst general anesthesia in combination with a catheter-based peripheral nerve block (catheter group) and general anesthesia alone in patients receiving lower extremity amputation. The rate of postoperative pulmonary complications was identified as a primary endpoint. The secondary outcomes assessed were acute post-operative pain scores and opioid consumption up to 48 hours. Our analysis was adjusted for potential confounding variables inclusive of demographics, medical comorbidities, type of surgical procedure and smoking status.

RESULTS

Ninety-six patients were included in the study (61 in the general anesthesia group, 35 in the catheter group). After adjusting for baseline demographics, comorbidities, surgical technique and smoking status, the odds of postoperative pulmonary complications were significantly lower with catheter-based peripheral nerve block in comparison to general anesthesia alone, OR 0.11 [95% CI, 0.01- 0.88] (P = 0.048). The decrease in acute pain scores was also observed in the catheter group when compared to general anesthesia alone, OR 0.72 [95% CI, 0.56 - 0.93] (P = 0.012). Similarly, the opioid consumption was also lower in the catheter group in comparison to general anesthesia alone, OR 0.97 [95% CI, 0.95 - 0.99] (P = 0.025).

CONCLUSION

Preemptive use of continuous peripheral nerve block in patients undergoing lower extremity amputation reduces the incidence of pulmonary complications, acute postoperative pain scores and narcotic use in post-operative period.

Simplified Algorithm for Evaluation of Perioperative Hypoxia and Hypotension (SALVATION): A Practical Echo-guided Approach Proposal

Despite the valuable use of modern applications of perioperative ultrasound across multiple disciplines, there have been limitations to its implementation, restricting its impact on patient-based clinical outcomes. Point-of-care ultrasound evaluation of hypoxia and hypotension is an important tool to assess the underlying undifferentiated etiologies in a timely manner. However, there is a lack of consensus on the formal role of ultrasound during evaluation of perioperative hypoxia or hypotension. The previous ultrasound algorithms have adopted a complex technique that possibly ignore the pathophysiologic mechanisms underlying the conditions presenting in a similar fashion. The authors here propose a simple, sequential and focused multiorgan approach, applicable for the evaluation of perioperative hypotension and hypoxia in emergency scenarios. The authors believe this approach will enhance the care provided in the postanesthesia care unit, operating room, and intensive care unit.

Closed Bronchoscopy System: An Innovative Approach to Minimize Aerosolization During Bronchoscopy

Health care workers performing aerosolizing procedures on patients with transmissible infections such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are at high-risk for disease acquisition. Current guidelines designed to protect health care workers during aerosolizing procedures prioritize personal protective equipment and enhanced infection control techniques, in particular during procedures such as intubation. To date, little emphasis has been placed on risk mitigation in the setting of bronchoscopy, a procedure that has significant aerosolization potential. Herein, we present an innovative closed bronchoscopy system designed to reduce aerosolization during bronchoscopy.

Workflow of Ultrasound-Guided Arterial Access

Arterial line cannulations frequently are performed in various clinical settings to facilitate hemodynamic monitoring and metabolic assessments. Palpation-guided technique generally is performed due to the superficial nature of the peripheral arteries; however, this approach may be challenging in patients with obesity, edema, and hypotension. Difficult line placements are a significant contributor of reduced operating room efficiency due to time delays seen in procedural workflow. Real-time ultrasound guidance is shown to improve success rates of arterial cannulation and reduction in multiple attempts, leading to time efficiency and less likelihood of arterial spasms or hematoma formation. In this report, the authors demonstrate the workflow of ultrasound-guided arterial line cannulation, outline the features of their institutional multi-modal training project for quality improvement, and evaluate the possible effect of the initiative on surgical delays seen with difficult line placements.

Analysis of Kinematic Differences in Hand Motion between Novice and Experienced Operators in IR: A Pilot Study

PURPOSE

To prospectively validate electromagnetic hand motion tracking in interventional radiology to detect differences in operator experience using simulation.

METHODS

Sheath task: Six attending interventional radiologists (experts) and 6 radiology trainees (trainees) placed a wire through a sheath and performed a "pin-pull" maneuver, while an electromagnetic motion detection system recorded the hand motion. Radial task: Eight experts and 12 trainees performed palpatory radial artery access task on a radial access simulator. The trainees repeated the task with the nondominant hand. The experts were classified by their most frequent radial artery access technique as having either palpatory, ultrasound, or overall limited experience. The time, path length, and number of movements were calculated. Mann-Whitney U tests were used to compare the groups, and P < .05 was considered significant.

RESULTS

Sheath task: The experts took less time, had shorter path lengths, and used fewer movements than the trainees (11.7 seconds ± 3.3 vs 19.7 seconds ± 6.5, P < .01; 1.1 m ± 0.3 vs 1.4 m ± 0.4, P < .01; and 19.5 movements ± 8.5 vs 31.0 movements ± 8.0, P < .01, respectively). Radial task: The experts took less time, had shorter path lengths, and used fewer movements than the trainees (24.2 seconds ± 10.6 vs 33.1 seconds ± 16.9, P < .01; 2.0 m ± 0.5 vs 3.0 m ± 1.9, P < .001; and 36.5 movements ± 15.0 vs 54.5 movements ± 28.0, P < .001, respectively). The trainees had a shorter path length for their dominant hand than their nondominant hand (3.0 m ± 1.9 vs 3.5 m ± 1.9, P < .05). The expert palpatory group had a shorter path length than the ultrasound and limited experience groups (1.8 m ± 0.4 vs 2.0 m ± 0.4 and 2.3 m ± 1.2, respectively, P < .05).

CONCLUSIONS

Electromagnetic hand motion tracking can differentiate between the expert and trainee operators for simulated interventional tasks.

Cardiopulmonary Bypass Suppresses Forkhead Box O3 and Downstream Autophagy in the Diabetic Human Heart

BACKGROUND

Autophagy is an integral component of cellular homeostasis and metabolism. The exact mechanism of impaired autophagy in diabetes mellitus is unknown. Forkhead Box O3 (FOXO3α) is a key regulator of oxidative stress-related responses. We hypothesize FOXO3α is a direct upstream regulator of the autophagy pathway, and its upregulation is compromised in diabetic patients during stress of cardiopulmonary bypass (CPB).

METHODS

The study enrolled 32 diabetic and 33 nondiabetic patients undergoing a cardiac surgical procedure on CPB. Right atrial tissue and serum samples were collected before and after CPB per protocol. A set of key components were quantitatively assessed and compared by microarray, immunoblotting, and immunohistochemistry studies. Data were analyzed using paired or unpaired student test. A P of <.05 or less was considered significant.

RESULTS

Serum microarray showed FOXO3α was upregulated in the diabetic vs nondiabetic group after CPB (P = .033), autophagy-related 4B gene and Beclin 1 gene were greatly upregulated in the nondiabetic group (P = .028 and P = .002, respectively). On immunoblotting, there was upregulation of FOXO3α in the nondiabetic patients after CPB (P = .003). There were increased levels of Beclin-1, Bcl-2, and light chain 3B after CPB in the nondiabetic group only (P = .016, P = .005, P = .002, respectively). Sirtuin 1, Unc-51-like autophagy activating kinase 1 (ULK1), peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α), and mammalian target of rapamycin (mTOR) were not significantly changed in the nondiabetic group after CPB.

CONCLUSIONS

Compared with nondiabetic patients, there was no significant upregulation of FOXO3α in diabetic patients, which could possibly explain the lack of upregulation of the autophagy process after CPB. FOXO3α could potentially serve as a therapeutic target to improve cellular homeostasis.

Handheld Point-of-Care Ultrasound Probes: The New Generation of POCUS

Recent advances in ultrasound technology have made ultrasound equipment more versatile, portable, and accessible than ever. Modern handheld, ultra-portable ultrasound devices have been developed by multiple companies and are contributing to make bedside ultrasound evaluation a practice available to all physicians. The significance of making point-of-care ultrasound (POCUS) a common practice that all physicians eventually can use in the evaluation of their patients is changing the way medicine is practiced, allowing physicians to quickly obtain valuable information to complement the traditional physical examination. Despite the proven benefits of using bedside ultrasound imaging as a part of the patient evaluation and for procedure guidance, adoption of this technology still is not widespread among anesthesiology clinicians nor is there uniform teaching of ultrasound skills to anesthesia residents and faculty. Among obstacles that have been identified as precluding achievement of the goal of widespread utilization of POCUS among anesthesia professionals and trainees, are the availability of equipment for all physicians when it is needed and lack of instructor supervision for trainees who desire to use ultrasound but do not always have an instructor knowledgeable in POCUS with them when an ultrasound examination is warranted. Herein, the characteristics, advantages, and limitations of available ultra-portable, handheld ultrasound devices are analyzed, with a focus on the Butterfly iQ (Butterfly Network, Inc, Guilford, CT) pocket probe, which is available at the authors’ institution, and how some of its features, such as the capacity to emulate multiple transducers and its cloud-sharing and teleguidance technology, may contribute to increase the availability and use of POCUS by anesthesia clinicians.

Impact of Left Atrial Appendage Exclusion on Short-Term Outcomes in Isolated Coronary Artery Bypass Graft Surgery

BACKGROUND

The objective of this study was to evaluate the impact of left atrial appendage (LAA) exclusion on short-term outcomes in patients with atrial fibrillation undergoing isolated coronary artery bypass graft surgery.

METHODS

We queried the 2010 to 2014 National Readmissions Database for patients who underwent coronary artery bypass graft repair with and without LAA ligation by using International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes (International Classification of Diseases, Ninth Revision, Clinical Modification: 36.1xx). Only patients with a history of atrial fibrillation were included in our analysis. The primary outcome of our study was 30-day readmissions following discharge. Secondary outcomes were in-hospital mortality and stroke. To assess the postoperative outcomes, we used multivariate logistic regression models to adjust for clinical and demographic covariates.

RESULTS

In total, we analyzed 253 287 patients undergoing coronary artery bypass graft surgery, 7.0% of whom received LAA closure. LAA exclusion was associated with a greater risk of postoperative respiratory failure (8.2% versus 6.2%, P<0.0001) and acute kidney injury (21.8% versus 18.5%, P<0.0001), but it did not significantly change the rate of blood transfusions or occurrence of cardiac tamponade. LAA exclusion was associated with a nonsignificant reduction in stroke (7.9% versus 8.6%, P=0.12), no difference in in-hospital mortality (2.2% versus 2.2% P=0.99), and a greater risk of 30-day readmission (16.0% versus 9.6%, P<0.0001). After covariate adjustment, LAA ligation remained a significant predictor of 30-day readmission (odds ratio, 1.640 [95% CI, 1.603-1.677], P<0.0001).

CONCLUSIONS

LAA exclusion during isolated coronary artery bypass graft surgery in patients with atrial fibrillation is associated with a higher rate of 30-day readmission. Postoperative measures to mitigate the loss of the hormonal and hemodynamic effects of the LAA may increase the therapeutic benefit of this procedure.

Tool to improve qualitative assessment of left ventricular systolic function

Interactive online learning tools have revolutionized graduate medical education and can impart echocardiographic image interpretive skills. We created self-paced, interactive online training modules using a repository of echocardiography videos of normal and various degrees of abnormal left ventricles. In this study, we tested the feasibility of this learning tool. Thirteen anesthesia interns took a pre-test and then had 3 weeks to complete the training modules on their own time before taking a post-test. The average score on the post-test (74.6% ± 11.08%) was higher than the average score on the pre-test (57.7% ± 9.27%) (P < 0.001). Scores did not differ between extreme function (severe dysfunction or hyperdynamic function) and non-extreme function (normal function or mild or moderate dysfunction) questions on both the pre-test (P = 0.278) and post-test (P = 0.093). The interns scored higher on the post-test than the pre-test on both extreme (P = 0.0062) and non-extreme (P = 0.0083) questions. After using an online educational tool that allowed learning on their own time and pace, trainees improved their ability to correctly categorize left ventricular systolic function. Left ventricular systolic function is often a key echocardiographic question that can be difficult to master. The promising performance of this educational resource may lead to more time- and cost-effective methods for improving diagnostic accuracy among learners.

Crossed Swords Sign: A 3-Dimensional Echocardiographic Appearance

Intraoperative evaluation of mitral regurgitation is a complex undertaking. Bileaflet prolapse/flail can result in divergent mitral regurgitation jets with a characteristic "crossed swords sign" appearance. We present a case of divergent mitral regurgitation jets that were detected intraoperatively and evaluated using 3-dimensional imaging. The accurate assessment of eccentric mitral regurgitation jets, especially bilateral eccentric mitral regurgitation jets, is challenging before surgical repair. Intraoperative 3-dimensional transesophageal echocardiography with and without color-flow Doppler can significantly improve the localization of the anatomical lesion.

Impact of left ventricular outflow tract flow acceleration on aortic valve area calculation in patients with aortic stenosis

Objective

Due to its circular shape, the area of the proximal left ventricular tract (PLVOT) adjacent to aortic valve can be derived from a single linear diameter. This is also the location of flow acceleration (FA) during systole, and pulse wave Doppler (PWD) sample volume in the PLVOT can lead to overestimation of velocity (V₁) and the aortic valve area (AVA). Therefore, it is recommended to derive V₁ from a region of laminar flow in the elliptical shaped distal LVOT (away from the annulus). Besides being inconsistent with the assumptions of continuity equation (CE), spatial difference in the location of flow and area measurement can result in inaccurate AVA calculation. We evaluated the impact of FA in the PLVOT on the accuracy of AVA by continuity equation (CE) in patients with aortic stenosis (AS).

Methods

CE-based AVA calculations were performed in patients with AS once with PWD-derived velocity time integral (VTI) in the distal LVOT (VTI_LVOT) and then in the PLVOT to obtain a FA velocity profile (FA-VTI_LVOT) for each patient. A paired sample t-test (P < 0.05) was conducted to compare the impact of FA-VTI_LVOT and VTI_LVOT on the calculation of AVA.

Result

There were 46 patients in the study. There was a 30.3% increase in the peak FA-VTI_LVOT as compared to the peak VTI_LVOT and AVA obtained by FA-VTI_LVOT was 29.1% higher than obtained by VTI_LVOT.

Conclusion

Accuracy of AVA can be significantly impacted by FA in the PLVOT. LVOT area should be measured with 3D imaging in the distal LVOT.

Immediate Preoperative Transthoracic Echocardiography for the Prediction of Postoperative Atrial Fibrillation in High-Risk Cardiac Surgery

OBJECTIVE

The present study aimed to validate the utility of bedside cardiac ultrasound to identify patients for the risk of postoperative atrial fibrillation (POAF).

DESIGN

A prospective cohort study of consecutive patients.

SETTING

Single-center tertiary referral center.

PARTICIPANTS

After Institutional Review Board consent, 169 patients undergoing elective cardiac surgery were enrolled in the study.

INTERVENTIONS

A preoperative transthoracic echocardiographic interrogation assessing diastolic function was performed. Measurements were assessed offline with experienced echocardiographers blinded to clinical outcomes.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was POAF during the first 72 hours after surgery. A total of 169 patients completed the study, 44 of whom (26.0%) developed POAF, and 39 (25.2%) had diastolic dysfunction. Patients with POAF had a higher rate of postoperative heart failure, reintubation within 24 hours of surgery, and length of stay (p = 0.002, 0.01, and 0.0006, respectively). Predictors significant for POAF included increasing age, left atrial volume indexed to body surface area (LAVI), and diastolic dysfunction (p = 0.02, 0.0001, and 0.001, respectively). Multivariate spline regressions demonstrated a nonlinear correlation between increasing LAVI and risk of POAF.

CONCLUSION

Left atrial volume can be assessed efficiently preoperatively to provide superior risk stratification over clinical factors and diastolic parameters alone for the prediction of POAF. Furthermore, the present study demonstrated that the cutoffs of chamber quantification currently used do not appropriately capture the increased risk of POAF. Thus, LAVI provides a simple measure to identify patients who are in need of targeted prophylaxis for POAF.