Role of surgical simulation on self-reported confidence level on cardiothoracic surgical trainees.

BACKGROUND: Simulated self-practice using simulation models could improve fine motor skills and self confidence in surgical trainees. AIMS: The purpose of this study is to evaluate on self-reported confidence level in cardiothoracic surgical trainees by using surgical simulation models. METHODS: We conducted a cross-sectional study on all surgeons (n=10) involved in MIS simulation training. All surgeons are required to perform on three minimally invasive surgery (MIS) procedures (Mitral Valve Repair, Mitral Valve Replacement and Aortic Valve Replacement). A questionnaire was designed based on two existing scales related to self-confidence, the surgical self-efficacy scale [SSES] and the perceived competency scale [PCS]. We assessed their self-confidence (before and after training) in the use of simulation in MIS procedures using rating scales 1-5. The mean score was calculated for each domain and used as the predictor variable. We also developed six questions (PCS) using Objective Structured Assessment of Technical Skills (OSAT) related to each domain and asked participants how confident they were after performing each MICS procedure. RESULTS: The mean score was 4.7 for all assessed domains, except "knowledge" (3.8). Surgeons who had performed one or more MIS procedures had higher scores (P<0.05). There was no correlation between the number of MIS procedures performed and self-confidence scores. CONCLUSIONS: The results indicate that the cardiac surgery training based on MIS simulation improves trainees and consultants in terms of the level of self-confidence. Although surgeons generally have high levels of self-confidence after simulation training in MIS cardiac procedures, there is still room for improvement with respect to technical skills related to the procedure itself and its results.

Self-Practice Program for Beating-Heart Minimally Invasive Coronary Anastomosis Using a Homemade Low-Fidelity Simulator: A Proof of Concept.

OBJECTIVE: We evaluated the effectiveness of a consistent and structured self-practice coronary anastomosis program using a homemade low-fidelity beating-heart simulator. METHODS: An intermediary trainee was subjected to an 8-week structured self-practice program. The program was divided into 2 parts of nonbeating and beating practices with a minimum number of timed anastomoses. Each part was followed by an assessment using an objective skills assessment tool score. The beating-heart simulator was built using motorized toy blocks connected wirelessly to a smartphone application. This was coded to enable rate selection. A junior consultant was compared to the subject at the end of the program. Both were tasked to perform 1 coronary anastomosis for both off-pump coronary artery bypass (OPCAB) and minimally invasive CAB (MICS) setup. The primary outcomes were anastomotic time and score compared with the junior consultant. Secondary outcomes were progression of anastomotic time and score throughout the program. RESULTS: Overall performance of the studied subject approached the performance of the junior consultant in terms of time (OPCAB, 489 vs 605 s; MICS, 712 vs 652 s) and scores (OPCAB, 21 vs 20.7; MICS, 19 vs 20.6). There were inverse correlations between anastomosis time and number of practices for both nonbeating and beating anastomoses. Overall improvement was observed in terms of assessment scoring by 26.6%. CONCLUSIONS: A structured self-practice program using an affordable and accessible simulator was able to help trainees overcome the MICS anastomosis learning curve quicker when introduced earlier. This may encourage earlier adoption of MICS among surgeons.

Transit time flow measurement and outcome in coronary artery bypass grafting for surgeon and trainee.

BACKGROUND: Trainees need to operate under appropriate supervision to become competent. Transit time flow measurement (TTFM) is useful in detecting intraoperative graft failures during coronary artery bypass grafting (CABG). This study aims to compare the intra- and postoperative outcomes, including TTFM, of isolated CABG performed by a single consultant versus trainees and to determine the relationship between the pulsatility index (PI) and postoperative outcomes. METHODS: This retrospective study included 155 isolated CABG cases. Intraoperative outcomes included duration of cardiopulmonary bypass (CPB) and aortic cross-clamp and TTFM for arterial and venous grafts. Postoperative outcomes included common postoperative complications and mortality. The odds ratios of postoperative complications and mortality for arterial and venous grafts with PI ≤3 relative to grafts with PI >3 were determined with multiple logistic regression. RESULTS: The duration of CPB and aortic cross-clamp was significantly shorter in the consultant's group. TTFM for both arterial and venous grafts were similar and no significant differences in postoperative complications and mortality were detected between the two groups. Patients with arterial grafts with PI ≤3 were less likely to require an intra-aortic balloon pump (IABP) or be ventilated for a prolonged period. No significant differences in postoperative outcomes and mortality were detected between venous grafts with PI ≤3 and PI >3. CONCLUSIONS: Trainees can achieve good results in isolated CABG with appropriate case selection. Patients with arterial grafts with PI ≤3 have better postoperative outcomes.

Comparison of diametric and volumetric changes in Stanford type B aortic dissection patients in assessing aortic remodeling post-stent graft treatment.

BACKGROUND: The study aims to analyze the correlation between the maximal diameter (both axial and orthogonal) and volume changes in the true (TL) and false lumens (FL) after stent-grafting for Stanford type B aortic dissection. METHOD: Computed tomography angiography was performed on 13 type B aortic dissection patients before and after procedure, and at 6 and 12 months follow-up. The lumens were divided into three regions: the stented area (Region 1), distal to the stent graft to the celiac artery (Region 2), and between the celiac artery and the iliac bifurcation (Region 3). Changes in aortic morphology were quantified by the increase or decrease of diametric and volumetric percentages from baseline measurements. RESULTS: At Region 1, the TL diameter and volume increased (pre-treatment: volume =51.4±41.9 mL, maximal axial diameter =22.4±6.8 mm, maximal orthogonal diameter =21.6±7.2 mm; follow-up: volume =130.7±69.2 mL, maximal axial diameter =40.1±8.1 mm, maximal orthogonal diameter =31.9+2.6 mm, P<0.05 for all comparisons), while FL decreased (pre-treatment: volume =129.6±150.5 mL; maximal axial diameter =43.0±15.8 mm; maximal orthogonal diameter =28.3±12.6 mm; follow-up: volume =66.6±95.0 mL, maximal axial diameter =24.5±19.9 mm, maximal orthogonal diameter =16.9±13.7, P<0.05 for all comparisons). Due to the uniformity in size throughout the vessel, high concordance was observed between diametric and volumetric measurements in the stented region with 93% and 92% between maximal axial diameter and volume for the true/false lumens, and 90% and 92% between maximal orthogonal diameter and volume for the true/false lumens. Large discrepancies were observed between the different measurement methods at regions distal to the stent graft, with up to 46% differences between maximal orthogonal diameter and volume. CONCLUSIONS: Volume measurement was shown to be a much more sensitive indicator in identifying lumen expansion/shrinkage at the distal stented region.

Mediastinal liposarcoma: a rare visceral mediastinal tumour.

Liposarcoma is the second most common type of soft tissue malignancy in adults. They are malignant tumours with a mesenchymal origin. Mediastinal liposarcoma accounts for <1% of mediastinal tumours and 2% of liposarcoma. We report a patient with mediastinal liposarcoma who presented with cardiac tamponade, 25 years after the initial liposarcoma in the popliteal fossa.

Quantitative and qualitative comparison of low- and high-cost 3D-printed heart models.

Current visualization techniques of complex congenital heart disease (CHD) are unable to provide comprehensive visualization of the anomalous cardiac anatomy as the medical datasets can essentially only be viewed from a flat, two-dimensional (2D) screen. Three-dimensional (3D) printing has therefore been used to replicate patient-specific hearts in 3D views based on medical imaging datasets. This technique has been shown to have a positive impact on the preoperative planning of corrective surgery, patient-doctor communication, and the learning experience of medical students. However, 3D printing is often costly, and this impedes the routine application of this technology in clinical practice. This technical note aims to investigate whether reducing 3D printing costs can have any impact on the clinical value of the 3D-printed heart models. Low-cost and a high-cost 3D-printed models based on a selected case of CHD were generated with materials of differing cost. Quantitative assessment of dimensional accuracy of the cardiac anatomy and pathology was compared between the 3D-printed models and the original cardiac computed tomography (CT) images with excellent correlation (r=0.99). Qualitative evaluation of model usefulness showed no difference between the two models in medical applications.

Obstructive sleep apnoea and open heart surgery: a review of its incidence and impact to patients.

BACKGROUND: Obstructive sleep apnea (OSA) is a serious health disorder which contributes to cardiovascular complications, decreased work productivity, automobile accidents, and death. This condition is characterized by a temporary cessation of breathing resulting due to upper airway closure during a person's sleep. Strain to the heart caused by this repetitive hypoxic insult can lead to postoperative complications for patients undergoing heart surgery. Recognizing cardiac surgical patients with OSA is important. Early recognition and intervention such as use of BiPAP device can reduce the postoperative complications due to OSA. METHODS: The aim of this study is to identify the incidence of unrecognized OSA in cardiac surgical patients. This is a retrospective analysis of a prospective data of the study which was done between July 2012 and July 2013 in University Malaya Medical Center. All patients undergoing elective cardiac surgery were recruited and the demographic data, questionnaire and the portable sleep study results were obtained. Patients were followed up till 30 days to record any complications. Data were entered in SPSS version 17 and analysis was done. RESULTS: The incidence of OSA was 61.4% and 43.5% were moderate to severe OSA. There was male predominance of OSA (79%) with a mean age of 60 years. OSA subjects had shorter inter-incisor distance (4.18±0.6 cm) and larger waistline (94.1±12.1 cm). The STOP-Bang questionnaire has a sensitivity of 75.8% in predicting apnoa-hypopnea index (AHI) ≥5/hour. CONCLUSIONS: OSA can be diagnosed with a simple screening questionnaire and a bedside portable sleep study. Cardiac patients diagnosed with OSA can be pre-emptively given extra attention in managing their postoperative care.

Flow pattern analysis in type B aortic dissection patients after stent-grafting repair: Comparison between complete and incomplete false lumen thrombosis.

Endovascular stent graft repair has become a common treatment for complicated Stanford type B aortic dissection to restore true lumen flow and induce false lumen thrombosis. Using computational fluid dynamics, this study reports the differences in flow patterns and wall shear stress distribution in complicated Stanford type B aortic dissection patients after endovascular stent graft repair. Five patients were included in this study: 2 have more than 80% false lumen thrombosis (group 1), while 3 others had less than 80% false lumen thrombosis (group 2) within 1 year following endovascular repair. Group 1 patients had concentrated re-entry tears around the abdominal branches only, while group 2 patients had re-entry tears that spread along the dissection line. Blood flow inside the false lumen which affected thrombus formation increased with the number of re-entry tears and when only small amounts of blood that entered the false lumen exited through the branches. In those cases where dissection extended below the abdominal branches (group 2), patients with fewer re-entry tears and longer distance between the tears had low wall shear stress contributing to thrombosis. This work provides an insight into predicting the development of complete or incomplete false lumen thrombosis and has implications for patient selection for treatment.

Metastatic Adenocarcinoma Presenting as Extensive Cavoatrial Tumor Thrombus.

The presence of tumor thrombus in the right atrium is frequently the result of direct intraluminal extension of infra-diaphragmatic malignancy into the inferior vena cava (IVC) or supradiaphragmatic carcinoma into the superior vena cava (SVC). Right atrial tumor thrombus with extension into both SVC and IVC has not been reported in the literature. We present a patient who presented with symptoms of right atrial and SVC obstruction. Imaging revealed presence of a thrombus in the right atrium, extending to the SVC and IVC, with the additional findings of a left adrenal mass and multiple liver lesions. The histopathological examination of the right atrial mass revealed metastatic adenocarcinoma cells. The patient was given a presumptive diagnosis of metastatic adenocarcinoma, most likely adrenal in origin, with multiple hepatic lesions suspicious for metastasis. The clinical outcome of the patient was not favorable; the patient succumbed before the adrenal mass could be confirmed to be the primary tumor. This case highlights that in patients manifesting with extensive cavoatrial thrombus as, the existence of primary carcinoma should be considered especially in the adrenal cortex or in the lung.

A perspective review on numerical simulations of hemodynamics in aortic dissection.

Aortic dissection, characterized by separation of the layers of the aortic wall, poses a significant challenge for clinicians. While type A aortic dissection patients are normally managed using surgical treatment, optimal treatment strategy for type B aortic dissection remains controversial and requires further evaluation. Although aortic diameter measured by CT angiography has been clinically used as a guideline to predict dilation in aortic dissection, hemodynamic parameters (e.g., pressure and wall shear stress), geometrical factors, and composition of the aorta wall are known to substantially affect disease progression. Due to the limitations of cardiac imaging modalities, numerical simulations have been widely used for the prediction of disease progression and therapeutic outcomes, by providing detailed insights into the hemodynamics. This paper presents a comprehensive review of the existing numerical models developed to investigate reasons behind tear initiation and progression, as well as the effectiveness of various treatment strategies, particularly the stent graft treatment.