Endovascular aortic aneurysm repair via the left ventricular apex of a beating heart.

An elderly man presented with a ruptured aortic arch, left lung compression, and hemoptysis. Multiple comorbidities and inadequate aortoiliac access disqualified him from conventional open repair or hybrid retrograde transarterial thoracic endovascular aortic repair (TEVAR). Because our center has recently reported that a thoracic aortic endograft can be successfully placed through the apex of the LV of a beating heart in a pig model, we received approval for the compassionate use of antegrade transapical TEVAR (TaTEVAR) with bilateral femoral-carotid revascularization to repair the aortic arch. As in our animal model, TaTEVAR was performed with accuracy and minimal hemodynamic compromise. The patient was quickly weaned from inotropic and respiratory support postoperatively and was neurologically intact, but died on the tenth postoperative day from respiratory failure.

Successful ventricular transapical thoracic endovascular graft deployment in a pig model.

PURPOSE: Aortoiliac occlusive disease may preclude retrograde thoracic endovascular aortic repair. This study evaluated the physiologic and anatomic feasibility of introducing an aortic endograft in an antegrade manner into the descending thoracic aorta of a pig through the left ventricular apex. METHODS: Twelve adult pigs were to undergo antegrade endograft deployment. Under fluoroscopic guidance, a stiff guidewire was introduced past the aortic valve and into the distal abdominal aorta through the left ventricular apex on a beating heart. An 18F introducer sheath containing a 24 x 36-mm aortic endograft was introduced and deployed in the descending thoracic aorta. The accuracy of graft delivery was determined at necropsy by measuring the distance from the trailing edge of the graft to the downstream margin of the ostium of the left subclavian artery. Aortic valve competency was assessed angiographically and at necropsy. Left ventricular function was assessed angiographically. Five hemodynamic and respiratory variables were recorded at 12 stages during the procedure and assessed for significant changes from baseline. RESULTS: One animal died during the sternotomy. All remaining pigs survived the experiment with minimal hemodynamic support. A significant drop in systolic blood pressure (75 +/- 2 to 60 +/- 4 mm Hg, P = .05) was noted when the aortic valve was crossed with an 18F sheath. The systolic blood pressure returned to baseline on endograft deployment and at the end of the procedure. Bradycardia was noted at several stages of the procedure, requiring treatment in two pigs. Eleven endografts were deployed; seven grafts were delivered within 5 mm and three grafts within 10 to 20 mm of the intended landing point. One graft was deployed 10 mm too proximally, covering the left subclavian artery. No aortic valvular insufficiency or left ventricular dysfunction was noted. CONCLUSION: An aortic endograft can be delivered in an antegrade manner transapically into the descending thoracic aorta in a pig model with a reasonable degree of accuracy and minimal hemodynamic compromise.

Risk factors associated with arteriovenous fistula failure after first radiologic intervention.

PURPOSE: Improving arteriovenous fistula (AVF) patency is an integral part of the care of hemodialysis patients, often requiring procedures such as percutaneous transluminal angioplasty (PTA). However, these interventions may fail to reduce AVF dysfunction and failure. The purpose of this study was to determine predictive factors for subsequent AVF failure post-PTA. METHODS: Data from 155 consecutive AVFs in 155 patients at a single institution who had undergone a first PTA and had at least 1 year of follow-up data were analyzed. Using survival analysis, we assessed primary and secondary patency, and identified predictive factors taking into account competing risks. RESULTS: Of the 155 patients, 52% required multiple subsequent PTAs; 32% of the AVFs were not in use prior to the first PTA. At first PTA, 83% had outflow vein stenosis (OVS), 26% had multiple stenoses and 43% of stenoses were longer than 2 cm. During follow-up, 1-, 2-, 3-year postintervention primary patency was 41%, 32%, 32% and secondary patency was 80%, 71% and 68%. AVFs with stenoses greater than 2 cm or OVS were at higher risk of requiring multiple PTAs (p = 0.04, 0.006). Factors associated with requiring a second PTA included stenosis greater than 2 cm (hazard ratio (HR) = 1.8, 95% confidence interval (CI) = 1.2-2.9), OVS (HR = 2.5, 95% CI = 1.1-5.4) and primary renal diagnosis of diabetes or renal vascular diseases (HR = 1.8, 95% CI = 1.1-2.9); after adjustments for competing risks, OVS and stenosis length remained associated with requiring subsequent PTAs. CONCLUSIONS: The location and size of the AVF stenosis at first PTA appear to be consistent factors associated with worse postintervention primary patency.

Mental practice in postgraduate training: a randomized controlled trial in mastoidectomy skills.

BACKGROUND: Mental practice, the cognitive rehearsal of a task in the absence of overt physical movement, has been successfully used in teaching complex psychomotor tasks including sports and music, and recently, surgical skills. The objectives of this study were, 1) To develop and evaluate a mental practice protocol for mastoidectomy 2) To assess the immediate impact of mental practice on a mastoidectomy surgical task among senior Otolaryngology─Head & Neck Surgery (OHNS) residents. METHOD: Three expert surgeons were interviewed using verbal protocol analysis to develop a mastoidectomy mental practice script. Twelve senior Residents from Canadian training programs were randomized into two groups. All Residents were video-recorded performing a baseline mastoidectomy in a temporal bone lab. The intervention group received mental practice training, while the control group undertook self-directed textbook study. All subjects were then video-recorded performing a second mastoidectomy. Changes in pre- and post-test scores using validated expert ratings, the Task Specific Evaluation of Mastoidectomy and the Global Evaluation of Mastoidectomy, were statistically analyzed. RESULTS: A mental practice script was successfully developed based on interviews of three expert surgeon-educators. Task Specific Evaluation and Global Evaluation scores increased in both the mental practice and textbook study groups; there was no significant difference between the two groups in the change in scores post-intervention. There was a high and statistically signficant correlation between evaluators on the outcome measures. CONCLUSIONS: We were not able to demonstrate a significant difference for the benefits of mental practice in mastoidectomy, possibly due to the sample size. However, mental practice is a surgical education tool which is portable, accessible, inexpensive and safe.

Development of a comprehensive vascular skills assessment for surgical trainees.

BACKGROUND: Although vascular skills are important to general surgeons, vascular surgery has become a separate specialty, and therefore, there may be an erosion of vascular skills acquired by general surgical trainees. The purpose of this study was to develop a reliable and valid comprehensive vascular skills assessment (CVSA) of both knowledge and technical skills. METHODS: Twenty-four of 38 general surgical residents at the University of British Columbia completed a two-part CVSA consisting of a written examination and a series of 4 technical stations in a skills laboratory. Technical performance was rated using validated scales. RESULTS: The mean overall CVSA score was 50%. The CVSA demonstrated construct validity, with improvement in scores with increasing postgraduate year level (P = .01). The overall reliability (Cronbach's alpha) was .90. CONCLUSIONS: The CVSA developed in this study is a comprehensive assessment of vascular skills that is both valid and reliable. It offers an objective and feasible assessment of general surgical trainees' vascular skills.

The assessment of technical and interpretative proficiency in echocardiography.

OBJECTIVES: We sought to assess the relationship between traditional measures of proficiency in echocardiography and an objective assessment of technical and interpretative skills. BACKGROUND: Determination of competency in echocardiography is currently based on the number of months of training, echocardiograms scanned, and echocardiograms interpreted. It has not been established whether completion of these requirements is a surrogate for competency. METHODS: In all, 22 cardiology fellows underwent an echocardiography objective structured clinical examination (OSCE). RESULTS: There was a correlation between the number of echocardiograms scanned and the interpretation (r = 0.45, P = .038) and scanning (r = 0.42, P = .048) scores. There was a weak correlation between the number of echocardiograms interpreted and interpretation scores (r = 0.33); and number of months of training and the scanning (r = 0.39) and interpretation (r = 0.42) scores. CONCLUSIONS: Technical and interpretative proficiency in echocardiography is not related to traditional measures. An objective assessment of acquisition and interpretation of echocardiographic data should be incorporated into the assessment of proficiency in echocardiography.

Validation of novel and objective measures of microsurgical skill: Hand-motion analysis and stereoscopic visual acuity.

Our purposes were: 1) to establish the predictive validity of stereoscopic visual acuity and microsurgical performance, and 2) to establish the construct and concurrent validity of hand-motion analysis as an objective and sensitive measure of microsurgical performance. Using a surgical microscope, 50 surgical residents completed a standardized microsurgical suturing task at baseline and following microsurgical training. Microsurgical performance was evaluated by blinded, expert microsurgeons using global rating scales. Measures of stereoscopic visual acuity and hand-motion analysis were correlated with expert global rating scores. Global rating scores correlated significantly with number of hand movements (r = -0.47, P = 0.001) and hand-travel distance (r = -0.37, P = 0.008). Economy of hand-motion improved significantly following microsurgical training (number of hand movements, P = 0.046; hand-travel distance, P = 0.04). Measures of stereoscopic visual acuity did not correlate significantly with global rating scores. Hand-motion analysis appears to be an objective and sensitive instrument for assessing microsurgical performance, with evidence of both concurrent and construct validity. The predictive validity of stereoscopic visual acuity and microsurgical performance remains unclear.

Laboratory based training in urological microsurgery with bench model simulators: a randomized controlled trial evaluating the durability of technical skill.

PURPOSE: We evaluated the durability of laboratory based technical skills training in urological microsurgery using bench model simulators. METHODS AND MATERIALS: A total of 50 junior surgery residents (post-graduate years 1 to 3) were recruited to participate in a focused training program in urological microsurgery. Prior to training subjects were randomized to receive hands-on training with bench model simulators (silicone tubing or live rat vas deferens, 40) or didactic training alone (10). Four months following the original training program the technical performance of 18 returning subjects (13 from the bench model and 5 from the didactic training group) was reevaluated using a high fidelity, live animal model (vasovasostomy and rat vas deferens). Outcome measures included blinded, expert assessment of videotaped performance using checklists and global rating scores, and evaluation of anastomotic patency. RESULTS: The retention test checklist (p <0.001), global rating scores (p <0.001) and anastomotic patency rates (p = 0.05) in the live animal model remained significantly higher for subjects who originally received hands-on bench model training compared with those who received didactic training alone. The number of interim practice opportunities with microsurgery correlated significantly with expert global ratings of surgical performance irrespective of the nature of training (r = 0.54, p = 0.02). CONCLUSIONS: Laboratory based technical skills training with bench models can lead to a significant retention of technical skill by novice surgeons. Measured performance improvements appear to be durable with time. However, the opportunity for repeat hands-on practice appears to maximize the retention of technical skill.

The educational impact of bench model fidelity on the acquisition of technical skill: the use of clinically relevant outcome measures.

OBJECTIVE: To evaluate the impact of bench model fidelity on the acquisition of technical skill using clinically relevant outcome measures. METHODS: Fifty junior surgery residents participated in a 1-day microsurgical training course. Participants were randomized to 1 of 3 groups: 1) high-fidelity model training (live rat vas deferens; n = 21); 2) low-fidelity model training (silicone tubing; n = 19); or 3) didactic training alone (n = 10). Following training, all participants were assessed on the high- and low-fidelity bench models. Immediate outcome measures included procedure times, blinded, expert assessment of videotaped performance using checklists and global rating scales, anastomotic patency, suture placement precision, and final product ratings. Delayed outcome measures (obtained from the live rat vas deferens 30 days following training) included anastomotic patency, presence of a sperm granuloma, and the presence of sperm on microscopy. RESULTS: Following training, checklist (P < 0.001) and global rating scores (P < 0.001) on the bench model simulators were higher among subjects who received hands-on training, irrespective of model fidelity. Immediate anastomotic patency rates of the rat vas deferens were higher with increasing model fidelity training (P = 0.048). Delayed anastomotic patency rates were higher among subjects who received bench model training, irrespective of model fidelity (P = 0.02). Rates of sperm presence on microscopy were higher among subjects who received high-fidelity model training compared with subjects who received didactic training (P = 0.039) but did not differ among subjects in the high- and low-fidelity groups. CONCLUSIONS: Surgical skills training on low-fidelity bench models appears to be as effective as high-fidelity model training for the acquisition of technical skill among novice surgeons.