Prospective, randomised and blinded comparison of proficiency-based progression full-physics virtual reality simulator training versus invasive vascular experience for learning carotid artery angiography by very experienced operators

Introduction

We assessed the transfer of training (ToT) of virtual reality simulation training compared to invasive vascular experience training for carotid artery angiography (CA) for highly experienced interventionists but new to carotid procedures.

Methods

Prospective, randomised and blinded.

Setting

Catheterisation and skills laboratories in the USA.

Participants

Experienced (mean volume=15 000 cases) interventional cardiologists (n=12) were randomised to train on virtual reality (VR) simulation to a quantitatively defined level of proficiency or to a traditional supervised in vivo patient case training.

Outcome measures

The observed performance differences in performing a CA between two matched groups were then blindly assessed using predefined metrics of performance.

Results

Experienced interventional cardiologists trained on the VR simulator performed significantly better than their equally experienced controls showing a significantly lower rate of objectively assessed intraoperative errors in CA. Performance showed 17–49% ToT from the VR to the in vivo index case.

Discussion

This is the first prospective, randomised and blinded clinical study to report that VR simulation training transfers improved procedural skills to clinical performance on live patients for experienced interventionists. This study, for the first time, demonstrates that VR simulation offers a powerful, safe and effective platform for training interventional skills for highly experienced interventionists with the greatest impact on procedural error reduction.

The future of simulation technologies for complex cardiovascular procedures

Changing work practices and the evolution of more complex interventions in cardiovascular medicine are forcing a paradigm shift in the way doctors are trained. Implantable cardioverter defibrillator (ICD), transcatheter aortic valve implantation (TAVI), carotid artery stenting (CAS), and acute stroke intervention procedures are forcing these changes at a faster pace than in other disciplines. As a consequence, cardiovascular medicine has had to develop a sophisticated understanding of precisely what is meant by 'training' and 'skill'. An evolving conclusion is that procedure training on a virtual reality (VR) simulator presents a viable current solution. These simulations should characterize the important performance characteristics of procedural skill that have metrics derived and defined from, and then benchmarked to experienced operators (i.e. level of proficiency). Simulation training is optimal with metric-based feedback, particularly formative trainee error assessments, proximate to their performance. In prospective, randomized studies, learners who trained to a benchmarked proficiency level on the simulator performed significantly better than learners who were traditionally trained. In addition, cardiovascular medicine now has available the most sophisticated virtual reality simulators in medicine and these have been used for the roll-out of interventions such as CAS in the USA and globally with cardiovascular society and industry partnered training programmes. The Food and Drug Administration has advocated the use of VR simulation as part of the approval of new devices and the American Board of Internal Medicine has adopted simulation as part of its maintenance of certification. Simulation is rapidly becoming a mainstay of cardiovascular education, training, certification, and the safe adoption of new technology. If cardiovascular medicine is to continue to lead in the adoption and integration of simulation, then, it must take a proactive position in the development of metric-based simulation curriculum, adoption of proficiency benchmarking definitions, and then resolve to commit resources so as to continue to lead this revolution in physician training.

Clinical features and outcomes of carotid artery stenting by clinical expert consensus criteria: a report from the CARE registry

BACKGROUND

In 2007, a multispecialty society task force published a clinical expert consensus document (CECD) on carotid stenting (CAS), containing recommendations for appropriate patient selection and quality of care. The CECD also inspired creation of a large, national registry of carotid revascularization, the Carotid Artery Revascularization and Endarterectomy (CARE) registry. Our goal here was to investigate whether initial CAS procedures submitted to CARE conformed to CECD recommendations, and examine their clinical outcomes.

METHODS

We analyzed CAS procedures for the period January 1, 2005 through December 31, 2008. These were grouped into those that conformed to CECD recommendations [CECD(+), n = 4,636, 79.8%] and those that did not [CECD(-), n = 1,168, 20.2%].

RESULTS

The CECD(+) patients were older than CECD(-) patients (71.5 +/- 10.3 vs. 67.6 +/- 10.3 years, P = 0.001, respectively), and more frequently had chronic kidney disease (46.9% vs. 17.8%, P = 0.001), chronic lung disease (33.0% vs. 12.4%, P = 0.001), ejection fraction <or= 0.30 (13.5% vs. 5.5%, P = 0.001) and contralateral carotid artery occlusion (12.7% vs. 4.6%, P = 0.001). Clinical outcomes at 30 days were similar, including death (1.24% vs. 0.76%, P = 0.184), stroke (5.32% vs. 5.34%, P = 0.954), and death, stroke, or MI (7.04% vs. 6.95%, P = 0.944).

CONCLUSIONS

Most CAS procedures submitted to CARE conformed to CECD recommendations for patient selection. For reported data, clinical outcomes at 30 days were similar for procedures meeting and those not meeting recommendations, and were similar to outcomes reported by other large registries. These findings suggest that acceptable patient selection criteria for CAS are employed as it expands beyond investigators into more widespread clinical practice.

Interventional stroke therapy: current state of the art and needs assessment

The primary therapeutic strategy for ischemic stroke, as for MI patients, is early reperfusion. Improvement in stroke treatment will require dedicated stroke centers to emulate MI quality indicators such as minimizing the "door-to-balloon time". A critical element in achieving this goal will be organizing the existing multidisciplinary pool of carotid interventionalists to provide the endovascular component of the acute care for ischemic stroke patients.

Integrated coronary revascularization with drug-eluting stents: Immediate and seven-month outcome

OBJECTIVE

We sought to demonstrate the safety and feasibility of an integrated coronary revascularization strategy that combines minimally invasive left internal thoracic artery to left anterior descending coronary artery anastomosis with drug-eluting stent implantation to non-left anterior descending coronary artery lesions.

METHODS

Over 18 months, 47 consecutive patients with multivessel coronary artery disease underwent thoracoscopic harvesting of the left internal thoracic artery to graft the left anterior descending coronary artery. Anastomoses were constructed by hand, off-pump, and under direct vision through a 4-cm non-rib-spreading, muscle-sparing chest incision. Non-left anterior descending coronary artery lesions were then treated percutaneously using sirolimus- or paclitaxel-eluting stents. Angiographic follow-up was performed in all patients.

RESULTS

Within the first 90 days of hospitalizations, there were no deaths, myocardial infarctions, neurologic events, or wound complications. Forty patients underwent left internal thoracic artery to left anterior descending coronary artery grafting, and 7 patients underwent left internal thoracic artery to left anterior descending coronary artery/diagonal sequential grafting for a total of 54 anastomoses. Angiographic patency scores were FitzGibbon A 96.2% (52/54) and FitzGibbon A + B 100% (54/54). A total of 65 drug-eluting stents were implanted in 61 non-left anterior descending coronary artery coronary lesions of which 49.1% (30/61) were type B2 or C lesions, including 5 left main lesions. Diabetes was present in 53.2% of patients (25/47). At a mean follow-up time of 7.0 +/- 4.8 months, the target lesion or vessel repeat revascularization rate was 6.6% (4/61) for drug-eluting stents and 1.9% (1/54) for left internal thoracic artery to left anterior descending coronary artery grafting. One anastomosis required balloon dilation, but no patients have required repeat coronary artery bypass grafting.

CONCLUSIONS

Integrated coronary revascularization using drug-eluting stents is feasible and safe. There are sufficient data to justify a randomized comparison of integrated coronary revascularization with standard coronary artery bypass grafting.

Learning Curves and Reliability Measures for Virtual Reality Simulation in the Performance Assessment of Carotid Angiography

OBJECTIVES

Improvement in performance as measured by metric-based procedural errors must be demonstrated if virtual reality (VR) simulation is to be used as a valid means of proficiency assessment and improvement in procedural-based medical skills.

BACKGROUND

The Food and Drug Administration requires completion of VR simulation training for physicians learning to perform carotid stenting.

METHODS

Interventional cardiologists (n = 20) participating in the Emory NeuroAnatomy Carotid Training program underwent an instructional course on carotid angiography and then performed five serial simulated carotid angiograms on the Vascular Interventional System Trainer (VIST) VR simulator (Mentice AB, Gothenburg, Sweden). Of the subjects, 90% completed the full assessment. Procedure time (PT), fluoroscopy time (FT), contrast volume, and composite catheter handling errors (CE) were recorded by the simulator.

RESULTS

An improvement was noted in PT, contrast volume, FT, and CE when comparing the subjects' first and last simulations (all p < 0.05). The internal consistency of the VIST VR simulator as assessed with standardized coefficient alpha was high (range 0.81 to 0.93), except for FT (alpha = 0.36). Test-retest reliability was high for CE (r = 0.9, p = 0.0001).

CONCLUSIONS

A learning curve with improved performance was demonstrated on the VIST simulator. This study represents the largest collection of such data to date in carotid VR simulation and is the first report to establish the internal consistency of the VIST simulator and its test-retest reliability across several metrics. These metrics are fundamental benchmarks in the validation of any measurement device. Composite catheter handling errors represent measurable dynamic metrics with high test-retest reliability that are required for the high-stakes assessment of procedural skills.

Virtual reality training for the operating room and cardiac catheterisation laboratory

CONTEXT

High-profile cases of medical errors in the USA and UK, and major reports from organisations such as the US Institute of Medicine and UK Senate of Surgery, have sensitised the public and medical profession. Training is a key area that must be tackled to positively affect the problem of medical errors, especially in surgery and interventional cardiology. Despite the radically novel skills required for minimally invasive surgery or interventional cardiology, current training has gone largely unchanged. At the end of the 20th century, the public and the medical profession have concluded that training on patients is no longer acceptable.

STARTING POINT

Recently, Teodor Grantcharov and colleagues (Br J Surg 2004; 91: 146-50) did a randomised double-blind trial which showed that training by virtual reality (VR) significantly reduces objectively assessed intraoperative errors in laparoscopic cholecystectomy. They used a low-fidelity VR simulator. Much more sophisticated VR simulators exist for endoscopy, gynaecology, laparoscopy, orthopaedics, otolaryngology, robotics, and urology. There are few studies on the efficacy of these simulators in improving the safety of procedures on patients.

WHERE NEXT

There needs to be more large and multicentre studies. Technical skills training for procedural based medicine continues to be an ad-hoc mentor-based experience for the trainee, with experience gained by practising on patients. The skills required now are so difficult to learn that this type of training is no longer acceptable. VR-simulator-based training does work, but further empirical evidence is required to convince the more conservative members of the medical community.

Safety and efficacy of a novel device for treatment of thrombotic and atherosclerotic lesions in native coronary arteries and saphenous vein grafts: results from the multicenter X-Sizer for treatment of thrombus and atherosclerosis in coronary applications trial (X-TRACT) study

Intervention in thrombotic lesions and diseased saphenous vein grafts frequently results in thromboembolic complications, including no-reflow, distal branch occlusion, periprocedural MI, and death. The utility of a novel thromboatherectomy device, the X-Sizer, was tested in 50 consecutive patients at nine U.S. centers. A total of 61 lesions were treated in 31 vein grafts and 19 native coronary arteries; thrombus was present in 78% of lesions, and TIMI 0-1 flow in 21%. TIMI 3 flow improved from 57% at baseline to 94% postprocedure. No patient developed visible distal thromboemboli, side-branch occlusion, or reduced antegrade flow. Thirty-day events included one death (2.0%), Q- or non-Q-wave MI in 4.0%, TVR in 6.0%, and any MACE in 6.0%. We conclude that the use of the X-Sizer prior to percutaneous intervention is safe in high-risk vein grafts and thrombotic lesions and results in a low rate of adverse events compared to historical controls.

Dipyridamole radionuclide ventriculography: a test with high specificity for severe coronary artery disease

Ventricular dysfunction induced by dipyridamole would be evidence of myocardial ischemia in patients with limited ability to undergo standard exercise testing. Radionuclide ventriculography before and after intravenous dipyridamole infusion was compared with the results of exercise radionuclide ventriculography in a prospective study of 31 patients undergoing coronary angiography. Among these patients, 21 (68%) had significant coronary artery disease (greater than or equal to 50% stenosis), 19 (61%) had severe coronary disease (greater than or equal to 70% stenosis) and 10 (32%) were "normal" (less than 50% stenosis). The left ventricular ejection fraction was calculated, and regional wall motion was scored on a 6 unit scale. In the normal patients, the ejection fraction (+/- SEM) increased 5.6 +/- 2% (units) during exercise and 7.9 +/- 1 units after dipyridamole (both p less than or equal to 0.004 compared with that during rest). However, in patients with coronary artery disease, the ejection fraction failed to increase during exercise or after dipyridamole. In the patients with coronary artery disease, regional wall motion decreased by 4.1 +/- 0.5 units during exercise (p less than 0.003) and by 1.8 units after dipyridamole (p less than 0.02). Receiver operating characteristic analysis demonstrated general comparability between the sensitivity and specificity of exercise and dipyridamole ventriculography, with "optimal" operating points that favored choosing high sensitivity for the former and high specificity for the latter. Specific subsets of patients with severe coronary atherosclerosis were analyzed with use of these criteria. In patients with severe stenosis (greater than or equal to 70%), the sensitivity of dipyridamole ventriculography was 67% compared with 89% for exercise ventriculography. However, at these levels of sensitivity, the specificity of dipyridamole ventriculography was 92% compared with 67% for exercise ventriculography. In this and other subsets of patients, the specificity of dipyridamole ventriculography exceeded that of exercise ventriculography. Thus, it is concluded that dipyridamole radionuclide ventriculography is moderately sensitive and highly specific for detecting severe coronary atherosclerosis. This technique provides a widely applicable, useful alternative to exercise ventriculography in the diagnosis of coronary atherosclerosis in patients who have limited exercise tolerance.

Glutathione redox pathway and reperfusion injury. Effect of N-acetylcysteine on infarct size and ventricular function

Glutathione peroxidase is an important enzyme in the degradative cascade of reactive oxygen free radicals. N-Acetylcysteine (NAC) is a low molecular weight compound that has been used clinically to replenish glutathione. To assess the role of the glutathione redox pathway on reperfusion injury, 23 animals underwent 90 minutes of proximal left anterior descending coronary artery occlusion followed by 24 hours of reperfusion with the administration of NAC (n = 11) or saline (n = 12) beginning 30 minutes into occlusion and continuing for 3 hours after reperfusion. Regional ventricular function was measured with contrast ventriculography, and regional myocardial blood flow was determined with microspheres. At 24 hours, the area at risk was defined in vivo with Monastral Blue, and the area of necrosis was defined by incubation in triphenyltetrazolium. Biopsies were taken from the ischemic and nonischemic zones to determine levels of total glutathione, superoxide dismutase and glutathione peroxidase activity, and reactivity to thiobarbituric acid, an index of lipid peroxidation. The rate-pressure product and myocardial blood flow were similar in the two groups throughout the study. No significant differences were noted in infarct size expressed as a percentage of the area at risk (28.6 +/- 5.3% vs. 36.6 +/- 6.0%) and of the total left ventricle (14.4 +/- 3.2% vs. 16.5 +/- 3.1%), and no differences were noted between the two groups on examination of the ischemic subendocardium by light and electron microscopy. Both groups exhibited similar degrees of dyskinesis during occlusion; however, treated animals showed significant improvement in regional radial shortening at 3 hours (3.4 +/- 2.4% vs. -2.4 +/- 2.1%, p less than 0.02) and 24 hours (9.2 +/- 2.2% vs. -2.5 +/- 6.3%, p less than 0.001) after reperfusion. No differences were present in total glutathione, thiobarbituric acid reactivity, or superoxide dismutase and glutathione peroxidase activity in the ischemic zones of the two groups. This study suggests that N-acetylcysteine treatment before reperfusion may reduce myocardial stunning but does not limit myocyte death after reperfusion.

Reduction of reperfusion injury in the canine preparation by intracoronary adenosine: importance of the endothelium and the no-reflow phenomenon

We hypothesized that the endogenous coronary vasodilator adenosine may reduce infarct size by progressively increasing reflow in a preparation of coronary occlusion-reperfusion. After 90 min of proximal left anterior descending artery occlusion, 20 dogs were randomized to blood reperfusion with (n = 10) or without (n = 10) adenosine into the proximal left anterior descending vessel at 3.75 mg/min for 60 min after reperfusion. Regional myocardial blood flow was determined serially with microspheres and regional ventricular function was assessed by a computerized radial shortening method. At 24 hr, the area at risk was defined in vivo with monastral blue dye and area of necrosis was determined after incubation of left ventricular slices in triphenyltetrazolium chloride. Hemodynamic variables were similar in the two groups during the experimental protocol. Infarct size was significantly reduced in treated animals, both when expressed as a percentage of the area at risk (9.9 +/- 2.8% vs 40.9 +/- 6.6%, p less than .001) and as a percentage of the left ventricle (4.6 +/- 1.3% vs 18.0 +/- 3.4%, p = .002). This was associated with significant improvement in radial shortening in the ischemic zone 24 hr after reperfusion (10.1 +/- 2.5 vs -2.8 +/- 2.2%, p less than .01). Regional myocardial blood flow was significantly increased in endocardial and epicardial regions from the lateral ischemic zone 1 hr after reperfusion in adenosine-treated animals. Light microscopy demonstrated decreased neutrophil infiltration in the ischemic zone and electron microscopy showed relative preservation of endothelial structure in the subendocardium with reduced neutrophil and red cell stagnation of capillaries in the treated group. These findings suggest that intracoronary administration of adenosine after reperfusion significantly reduces infarct size and improves regional ventricular function in the ischemic zone in the canine preparation.

Oxypurinol limits myocardial stunning but does not reduce infarct size after reperfusion

To explore the role of oxygen free radicals produced by the xanthine oxidase pathway on infarct size and left ventricular function, the effect of oxypurinol, an active metabolite of allopurinol and a potent noncompetitive inhibitor of xanthine oxidase, was assessed in a 90 min, closed-chest, canine preparation of occlusion-reperfusion. Animals were randomized to receive 25 mg/kg iv oxypurinol (n = 13) or saline (n = 13) 60 min after occlusion. Regional myocardial blood flow was measured with radioactive microspheres and regional ventricular function with contrast ventriculography. Hemodynamic variables, regional myocardial blood flow, and size of the occluded bed were similar in the two groups. Oxypurinol failed to reduce infarct size 24 hr after reperfusion when expressed as a percentage of the area at risk (36.3 +/- 4.9% vs 36.0 +/- 5.6%; p = NS). Both groups exhibited comparative radial shortening at baseline and similar degrees of dyskinesia 1 hr into occlusion (-6.6 +/- 1.2% vs -4.9 +/- 1.0%). However, oxypurinol-treated animals demonstrated an improved regional ventricular function at 3 hr after reperfusion (0.7 +/- 2.6% vs -2.8 +/- 2.0%) and a significant improvement at 24 hr (5.4 +/- 2.5% vs -3.2 +/- 1.7%; p less than .05). A reduced neutrophil infiltrate was observed in the border zone in treated animals. These findings suggest that oxygen free radicals derived from the xanthine oxidase pathway contribute to stunning of reversibly damaged myocardium but do not determine the final extent of myocardial necrosis in a canine preparation of reperfusion.

Electrocardiographic markers of cardiac metastasis

Cardiac metastases are often clinically inapparent but have important prognostic significance. A total of 1046 consecutive autopsies performed between 1981 and 1983 were reviewed, and 210 patients with both premortem and autopsy diagnoses of cancer were found, in whom a recent (less than 3 months before death) ECG was available. Of these patients, 47 had cardiac metastases (group I) and 163 did not (group II). In group I, 19 patients had new ECG changes suggestive of myocardial ischemia or injury, including either diffuse T wave inversion (10%), segmental (ECG pattern suggestive of a specific coronary distribution) T wave inversion (80%), or ST elevation (10%). None of these patients had symptoms suggestive of myocardial ischemia. In group II, six patients had ECG changes suggestive of myocardial ischemia or injury: four patients with preterminal sepsis, one with myocardial infarction, and one with aspergillus nodules within the myocardium. New atrial arrhythmias (seven patients) and low voltage (10 patients) were found with greater frequency in group I patients (p less than 0.0005 and p less than 0.00001, respectively, vs group II). Patients with normal ECGs were unlikely to have cardiac metastases; however, the finding of nonspecific ST-T wave changes was not helpful in differentiating the two groups. In clinically stable patients with cancer and no cardiac symptoms suggestive of ischemia, any new ECG change should raise the suspicion of cardiac metastases. The ECG finding of myocardial ischemia or injury has high specificity (96%, p less than 0.000001) for cardiac metastases.