Comparison of grading of aortic stenosis between transthoracic and transesophageal echocardiography in adult patients undergoing elective aortic valve replacement surgeries: A prospective observational study

Introduction: Intraoperative trans-esophageal echocardiography (TEE) has been found to underestimate severity of aortic stenosis (AS) compared to trans-thoracic echo (TTE). We conducted a prospective study comparing pre induction TTE and intra operative TEE grading of AS in patients posted for aortic valve replacement surgeries. Methods: Sixty patients with isolated AS who were undergoing aortic valve replacement were enrolled in our study. Baseline TTE was done and after induction of anesthesia, TEE was done. Mean gradient across aortic valve, peak jet velocity, aortic valve area (AVA) by continuity equation and dimensionless index (DI) were assessed in both. Results: Mean gradient decreased from 56.4 in TTE to 39.8 mm Hg in TEE leading to underestimation of AS in 74.5% of patients (P < 0.0). Mean of peak jet velocity also decreased from 500 in TTE to 386cm/s in TEE (P < 0.01). In 76 % of patients this led to reduction of AS grade from severe to moderate. Mean AVA was 0.67 cm2 in TTE and 0.69 cm2 in TEE. Though there was 0.02 cm2 increase, it was not statistically significant (P = 0.07). All the patients remained as severe AS in TEE. DI mean was 0.19 in both TTE and TEE (P = 0.14).It led to underestimation of severity in 6% of patients in TEE. Conclusion: Our study shows that AVA measurement by continuity equation and DI are reliable in grading aortic stenosis while performing intraoperative TEE. Mean gradient and jet velocity can be significantly reduced.

A survey of practices during cardiopulmonary bypass in India: An Indian association of cardiovascular and thoracic anesthesiologist endeavor

Context: Cardiac anesthesiologists play a key role during the conduct of cardiopulmonary bypass (CPB). There are variations in the practice of CPB among extracorporeal technologists in India. Aims: The aim of this survey is to gather information on variations during the conduct of CPB in India. Settings and Design: This was an online conducted survey by Indian College of Cardiac Anaesthesia, which is the research and academic wing of the Indian Association of Cardiovascular Thoracic Anaesthesiologists. Subjects and Methods: Senior consultants heading cardiac anesthesia departments in both teaching and nonteaching centers (performing at least 15 cases a month) were contacted using an online questionnaire fielded using SurveyMonkey™ software. There were 33 questions focusing on institute information, perfusion practices, blood conservation on CPB; monitoring and anesthesia practices. Results: The response rate was 74.2% (187/252). Fifty-one (26%) centers were teaching centers; 18% centers performed more than 1000 cases annually. Crystalloid solution was the most common priming solution used. Twenty-three percent centers used corticosteroids routinely; methylprednisone was the most commonly used agent. The cardioplegia solution used by most responders was the one available commercially containing high potassium St. Thomas solution (55%), followed by Del Nido cardioplegia (33%). Majority of the responders used nasopharyngeal site to monitor intraoperative patient temperature. Antifibrinolytics were commonly used only in patients who were at high risk for bleeding by 51% of responders, while yet, another 39% used them routinely, and 11% never did. About 59% of the centers insist on only fresh blood (<7 days old) when blood transfusion was indicated. The facility to use vaporizer on CPB was available in 62% of the centers. All the teaching centers or high volume centers in India had access to transesophageal echocardiography probe and echo machine, with 51% using them routinely and 38% using them at least sometimes. Conclusions: There is a wide heterogeneity in CPB management protocols among various Indian cardiac surgery centers. The survey suggests that adherence to evidence-based and internationally accepted practices appears to be more prevalent in centers that have ongoing teaching programs and/or have high volumes, strengthening the need to devise guidelines by appropriate body to help bring in uniformity in CPB management to ensure patient safety and high quality of clinical care for best outcomes.

Left ventricular outflow tract obstruction following aortic valve replacement: A review of risk factors, mechanism, and management

The presence of dynamic left ventricular outflow tract obstruction (LVOTO) can complicate the postoperative course of patients undergoing surgical aortic valve replacement (AVR). The phenomenon of LVOTO is a consequence of an interplay of various pathoanatomic mechanisms. The prevailing cardiovascular milieu dictates the hemodynamic significance of the resultant LVOTO in addition to the anatomical risk factors. A thorough understanding of the predisposing factors, mechanism, and hemodynamic sequel of the obstruction is pivotal in managing these cases. A comprehensive echocardiographic examination aids in risk prediction, diagnosis, severity characterization, and follow-up of management efficacy in the setting of postoperative LVOTO. The armamentarium of management modalities includes conservative (medical) and surgical options. A stepwise approach should be formulated based on the physiological and anatomical substrates predisposing to LVOTO. The index phenomenon occurs more frequently than appreciated and should be considered when the post-AVR patients exhibit hemodynamic instability unresponsive to conventional supportive measures. The present article provides an overview of various peculiarities of this under-recognized phenomenon in the context of the perioperative management of patients undergoing AVR.

Anesthetic challenges in minimally invasive cardiac surgery: Are we moving in a right direction.

Continuously growing patient’s demand, technological innovation, and surgical expertise have led to the widespread popularity of minimally invasive cardiac surgery (MICS). Patient’s demand is being driven by less surgical trauma, reduced scarring, lesser pain, substantially lesser duration of hospital stay, and early return to normal activity. In addition, MICS decreases the incidence of postoperative respiratory dysfunction, chronic pain, chest instability, deep sternal wound infection, bleeding, and atrial fibrillation. Widespread media coverage, competition among surgeons and hospitals, and their associated brand values have further contributed in raising awareness among patients. In this process, surgeons and anesthesiologist have moved from the comfort of traditional wide incision surgeries to more challenging and intensively skilled MICS. A wide variety of cardiac lesions, techniques, and approaches coupled with a significant learning curve have made the anesthesiologist’s job a challenging one. Anesthesiologists facilitate in providing optimal surgical settings beginning with lung isolation, confirmation of diagnosis, cannula placement, and cardioplegia delivery. However, the concern remains and it mainly relates to patient safety, prolonged intraoperative duration, and reduced surgical exposure leading to suboptimal treatment. The risk of neurological complications, aortic injury, phrenic nerve palsy, and peripheral vascular thromboembolism can be reduced by proper preoperative evaluation and patient selection. Nevertheless, advancement in surgical instruments, perfusion practices, increasing use of transesophageal echocardiography, and accumulating experience of surgeons and anesthesiologist have somewhat helped in amelioration of these valid concerns. A patient‑centric approach and clear communication between the surgeon, anesthesiologist, and perfusionist are vital for the success of MICS.

Short‑term prognostic value of perioperative coronary sinus‑derived‑serum cardiac troponin‑I, creatine kinase‑MB, lactate, pyruvate, and lactate‑pyruvate ratio in adult patients undergoing open heart surgery.

Objectives: To investigate the release pattern of different cardiac metabolites and biomarkers directly from the coronary sinus (CS) and to establish the diagnostic discrimination limits of each marker protein and metabolites to evaluate perioperative myocardial injury in patients undergoing cardiac surgery under cardiopulmonary bypass (CPB). Patients and Methods: Sixty-eight patients undergoing first mitral and/or aortic valve replacements with/without coronary artery bypass grafting and Bentall procedure under CPB and blood cardioplegic arrest were studied. All cardiac metabolites and biomarkers were measured in serial CS-derived blood samples at pre-CPB, immediate post aortic declamping, 10 minutes post-CPB and 12 hrs post-CPB. Results: Receiver operating characteristic curve analysis of cardiac biomarkers indicated lactate-pyruvate ratio as the superior diagnostic discriminator of myocardial injury with an optimal “cut-off” value >10.8 immediately after aortic declamping (AUC, 0.92; 95% CI: 0.85-0.98). Lactate was the second best diagnostic discriminator of myocardial injury with an optimal “cut-off” value >2mmol/l at immediately after aortic declamping (AUC, 0.89; 95% CI: 0.80-0.96). Cardiac troponin-I was the third best diagnostic discriminator of myocardial injury with an optimal “cut-off” value >2.1ng/ml at immediately after aortic declamping (AUC, 0.88; 95% CI: 0.80- 0.95). Creatine kinase-MB was the fourth best diagnostic discriminator of myocardial injury with an optimal “cut-off” value >58 log units/ml prior to decanulation (AUC, 0.85; 95% CI: 0.78-0.94). Conclusions: Measurable cardiac damage exists in all patients undergoing cardiac surgery under cardioplegic arrest. The degree of myocardial injury is more in patients with poor ventricular function and those requiring longer aortic clamp time. CS-derived lactate-pyruvate ratio, lactate, cTn-I served as superior diagnostic discriminators of peri-operative myocardial damage.

Strain and strain rate: An emerging technology in the perioperative period.

Newer noninvasive parameters are being used for perioperative detection of myocardial ischaemia. TDI and global strain rate are some of these parameters. TDI signal is a modification of the routine Doppler flow signal. It is obtained by using thresholding and filtering algorithms that reject echoes originating from the blood pool (by-passing the high pass filter). Set-Up of the machine by activating the TDI function allows decreasing the system gain using a low pass filter and eliminates the signal produced by blood flow. Doppler shift obtained from myocardial tissue motion are of higher amplitudes (reflectivity 40 dB higher) and move about 10 times slower than blood (velocity range: 0.06 to 0.24 m/s). Speckle tracking echocardiography (tissue tracking, 2D strain) utilizes routine gray-scale 2D echo images to calculate myocardial strain. Interactions of ultrasound with myocardium result in reflection and scattering. These interactions generate a finely gray-shaded, speckled pattern (acoustic marker). This speckled pattern is unique for each myocardial region and relatively stable throughout the cardiac cycle. Spatial and temporal image processing of acoustic speckles in both 2D and 3D allows for the calculation of myocardial velocity, strain, and Strain rate.

Comparison of levosimendan and nitroglycerine in patients undergoing coronary artery bypass graft surgery.

Background: Levosimendan a calcium ion sensitizer improves both systolic and diastolic functions. This novel lusitropic drug has predictable antiischemic properties which are mediated via the opening of mitochondrial adenosine triphosphate‑sensitive potassium channels. This action of levosimendan is beneficial in cardiac surgical patients as it improves myocardial contractility, decreases systemic vascular resistance (SVR), and increases cardiac index (CI) and is thought to be cardioprotective. We decided to study whether levosimendan has any impact on the outcomes such as the duration of ventilation, the length of Intensive Care Unit (ICU) stay, and the hospital stay when compared with the nitroglycerine (NTG), which is the current standard of care at our center. Materials and Methods: Forty‑seven patients undergoing elective coronary artery bypass surgery were randomly assigned to two groups receiving either levosimendan or NTG. The medications were started before starting surgery and continued until 24 h in the postoperative period. Baseline hemodynamic parameters were evaluated before beginning of the operation and then postoperatively at 3 different time intervals. N‑terminal fragment of pro‑brain natriuretic peptide (NT‑proBNP) levels were also measured in both groups. Results: In comparison to the NTG group, the duration of ventilation and length of ICU stay were significantly less in levosimendan group (P < 0.05, P = 0.02). NT‑proBNP level analysis showed a slow rising pattern in both groups and a statistically significant rise in the levels was observed in NTG group (P = 0.03, P = 0.02) in postoperative period when compared to levosimendan group of patients. Conclusion: Levosimendan treatment in patients undergoing surgical revascularization resulted in improved CI, decreased SVR and lower heart rate. And, thereby the duration of ventilation and length of ICU stay were significantly less in this group of patients when compared with NTG group.

Interventricular septal hydatid cyst: Transesophageal echocardiography as a therapeutic tool during bypass.

Cystic echinococcosis (hydatid disease) arising from infestation with a larval or adult form of the Echinococcus granulosus tapeworm is endemic in certain states of India, but affecting interventricular septum (IVS) solitarily is a scarce phenomenon. We present a rare case of transesophageal echocardiography guided management of IVS hydatid cyst even during cardiopulmonary bypass, which presented with a rather unusual complaint of repeated syncope.

Modified Blalock Taussig shunt: Comparison between neonates, infants and older children.

Objective: The aim was to compare various pre-and post-operative parameters and to identify the predictors of mortality in neonates, infants, and older children undergoing Modifi ed Blalock Taussig shunt (MBTS). Materials and Methods: Medical records of 134 children who underwent MBTS over a period of 2 years through thoracotomy were reviewed. Children were divided into three groups-neonates, infants, and older children. For analysis, various pre-and post-operative variables were recorded, including complications and mortality. Results: The increase in PaO2 and SaO2 levels after surgery was similar and statistically signifi cant in all the three groups. The requirement of adrenaline, duration of ventilation and mortality was signifi cantly higher in neonates. The overall mortality and infant mortality was 4.5% and 8%, respectively. Conclusion: Neonates are at increased risk of complications and mortality compared with older children. Age (<30 days), weight (<3 kg), packed red blood cells transfusion >6 ml/kg, mechanical ventilation >24 h and post shunt increase in PaO2 (PDiff) <25% of baseline PaO2 are independent predictors of mortality in children undergoing MBTS.

Minimally invasive cardiac surgery and transesophageal echocardiography.

Improved cosmetic appearance, reduced pain and duration of post‑operative stay have intensified the popularity of minimally invasive cardiac surgery (MICS); however, the increased risk of stroke remains a concern. In conventional cardiac surgery, surgeons can visualize and feel the cardiac structures directly, which is not possible with MICS. Transesophageal echocardiography (TEE) is essential during MICS in detecting problems that require immediate correction. Comprehensive evaluation of the cardiac structures and function helps in the confirmation of not only the definitive diagnosis, but also the success of surgical treatment. Venous and aortic cannulations are not under the direct vision of the surgeon and appropriate positioning of the cannulae is not possible during MICS without the aid of TEE. Intra‑operative TEE helps in the navigation of the guide wire and correct placement of the cannulae and allows real‑time assessment of valvular pathologies, ventricular filling, ventricular function, intracardiac air, weaning from cardiopulmonary bypass and adequacy of the surgical procedure. Early detection of perioperative complications by TEE potentially enhances the post‑operative outcome of patients managed with MICS.

Noonan syndrome: An anesthesiologist's perspective.

Noonan syndrome (NS) is one of the most common non chromosomal syndrome presenting to the cardiac anesthesiologist for the management of various cardiac lesions, predominantly pulmonary stenosis (PS) (80%) and hypertrophic obstructive cardiomyopathy (HOCM) (30%). The presence of HOCM in NS makes these children susceptible to acute congestive heart failure due to hemodynamic fluctuations, thus necessitating optimization of drug and fluid therapy, careful conduct of anesthesia and providing adequate analgesia in the perioperative period. We describe a case of four year old boy with NS who presented to us for the management of PS and HOCM. In our case, transesophageal echocardiography (TEE) played a major role in confirmation of the preoperative findings, detection of any new anomalies missed during the preoperative evaluation, intraoperative monitoring and assessment of the adequacy of repair in the immediate postoperative period. TEE provided invaluable help in taking critical surgical decisions, resulting in a favorable outcome.

Use of extracorporeal membrane oxygenator support to salvage an infant with anomalous left coronary artery from pulmonary artery.

Anomalous left coronary artery from pulmonary artery (ALCAPA) is a congenital acyanotic heart disease where the left coronary artery (LCA) arises from the pulmonary artery. This results in the LCA receiving blood supply from the low-pressure right ventricle having minimal extractable oxygen. The oxygen delivery to the left ventricle (LV) is severely hampered causing severe hypoxic LV dysfunction early in life. Early surgery prior to serious, irreversible LV dysfunction is the key to survival. Children with ALCAPA usually present in their first few weeks of life, with severe LV dysfunction. After surgical correction of the defect, the myocardium may not recover early from the presurgery myocardial dysfunction. We describe a case where extracorporeal membrane oxygenator was utilized as a means of ventricular support during this critical postoperative period resulting in a favorable outcome.

Extra corporeal membrane oxygenation after pediatric cardiac surgery: A 10 year experience.

Indications for extra corporeal membrane oxygenation (ECMO) after pediatric cardiac surgery have been increasing despite the absence of encouraging survival statistics. Modification of ECMO circuit led to the development of integrated ECMO cardiopulmonary bypass (CPB) circuit at the author's institute, for children undergoing repair of transposition of great arteries among other congenital heart diseases (CHD). In this report, they analyzed the outcome of children with CHD, undergoing surgical repair and administered ECMO support in the last 10 years. The outcome was analyzed with reference to the timing of intervention, use of integrated ECMO-CPB circuit, indication for ECMO support, duration of ECMO run and the underlying CHD. The results reveal a significantly improved survival rate with the use of integrated ECMO-CPB circuit and early time of intervention rather than using ECMO as a last resort in the management. The patients with reactive pulmonary artery hypertension respond favorably to ECMO support. In all scenarios, early intervention is the key to survival.

Is EuroSCORE applicable to Indian patients undergoing cardiac surgery.

Indian patients undergoing cardiac surgery have different demographics, clinical profile as well as risk profile, compared to the western population. The purpose of this study was to validate the European System for Cardiac Operative Risk Evaluation (EuroSCORE) risk stratification model in Indian patients undergoing cardiac surgery in a single cardiac center. Data from 1000 consecutive adult patients undergoing cardiac surgery (coronary artery bypass grafting or valve surgery) were prospectively collected as per the EuroSCORE model. The model's validity was assessed on the basis of its calibration power (Hosmer-Lemeshow test) and discriminatory power [area under receiver operating characteristic curve]. The patients were divided into three risk groups on the basis of their EuroSCORE. The Hosmer-Lemeshow test revealed a good calibration power (P = 0.73) and the area under the ROC curve was 0.8278, suggesting a good discriminative power. The predicted mortality was similar to observed mortality in low- and moderate-risk patients but the observed mortality in high-risk patients (15.6%) was double that of predicted mortality (7.5%). The risk factors prevalent in European population were not observed in Indian population. EuroSCORE accurately predicts mortality in low and moderate-risk Indian patients undergoing cardiac surgery but is less predictive for high-risk Indian patients. Updating and improvisation of EuroSCORE by incorporation of risk factors associated with rheumatic valvular heart disease which is more prevalent in India, may enable it to accurately predict mortality in high-risk patients also.