Realization of Open Software Chain for 3D Modeling and Printing of Organs in Simulation Centers: Example of Renal Pelvis Reconstruction.

OBJECTIVE: Three-dimensional (3D) printing has many uses in healthcare such as in surgical training. It is becoming an interesting tool finding new pedagogical purposes in medical simulation. In this study, using a process consisting of 3D modeling, a simulator dedicated to pyeloplasty was designed, manufactured, and evaluated by experts. DESIGN: With the aid of open-source software and computer-aided design software, 3D models of a renal parenchyma, a renal pelvis and a ureter were created. This renal apparatus was processed and crafted with additive manufacturing using soft polymer materials. Polyvinyl alcohol material was used to print the components in order to make them dissectible and to evaluate their use in surgical teaching. SETTING AND PARTICIPANTS: Seven expert surgeons evaluated the model by performing a pyeloplasty sequence established in a previous work. An evaluation grid with 8 items related to surgical movement was rated on a 5-point Likert scale to assess how similar working with the model was to actual surgery. RESULTS: Three items were rated with a score greater than or equal to 4 (Needle penetration, Thread-sliding, and Cutting Strength). Suture strength was rated with a score above 3.5 for both renal pelvis and ureter, whereas elasticity was rated below 3. Handling and mobility properties were rated above 3 for the renal pelvis and below 3 for the ureter. The cost of the unit was $0.30 per renal unit. The primary difference identified was a difference in elongation between polyvinyl alcohol material and real biological tissue. CONCLUSIONS: It is feasible to generate and print a low cost upper urinary tract model from patient data imagery using environmentally friendly products that can be used effectively in surgical training. The simulator has been able to reproduce sensations related to surgical movements for a low cost. Hereafter, research into the pedagogical benefits provided to students, and through them, patients, should be performed. 3D printing models can offer new opportunities for healthcare simulation specific to different surgical fields.

Complementary Role of the Computed Biomodelling through Finite Element Analysis and Computed Tomography for Diagnosis of Transcatheter Heart Valve Thrombosis.

INTRODUCTION: The TAVR procedure is associated with a substantial risk of thrombosis. Current guidelines recommend catheter-based aortic valve implantation for prohibitive-high-risk patients with severe aortic valve stenosis but acknowledge that the aetiology and mechanism of thrombosis are unclear. METHODS: From 2015 to 2018, 607 patients with severe aortic valve stenosis underwent either self-expandable or balloon-expandable catheter-based aortic valve implantation at our institute. A complementary study was designed to support computed tomography as a predictor of complications using an advanced biomodelling process through finite element analysis (FEA). The primary evaluation of study was the thrombosis of the valve at 12 months. RESULTS: At 12 months, 546 patients had normal valvular function. 61 patients had THVT while 6 showed thrombosis and dislodgement with deterioration to NYHA Class IV requiring rehospitalization. The FEA biomodelling revealed a strong link between solid uncrushed calcifications, delayed dislodgement of TAVR and late thrombosis. We observed an interesting phenomenon of fibrosis/calcification originating at the level of the misplaced valve, which was the primary cause of coronary obstruction. CONCLUSION: The use of cardiac CT and predictive biomodelling should be integrated into routine practice for the selection of TAVR candidates and as a predictor of negative outcomes given the lack of accurate investigations available. This would assist in effective decision-making and diagnosis especially in a high-risk cohort of patients.

Delayed prosthesis malposition after transcatheter aortic valve implantation causing coronaries obstruction.

A case of delayed malposition of a CoreValve device causing obstruction of coronary ostia is described. Nine months after the original implant, the patient developed an acute coronary syndrome and was readmitted to hospital. Angiogram demonstrated an ostial stenosis of both the left main stem and the right coronary ostia, which were filled by a paravalvular leakage of the bioprosthesis. Gated computed tomography scan with 3D reconstruction showed valve malposition with cusps situated 14 mm above the ostium of the right coronary and the presence of fibrous and calcific agglomerations associated to one of the cusp causing a tight stenosis of the left ostium. Computed tomography scan is a crucial imaging technique in the transcatheter aortic valve replacement field and in this case enabled us to identify an interesting phenomenon of fibrosis/calcification originating at the level of the misplaced valve, which was actually the triggering cause of the coronary obstruction. Considering the reported need for more accurate investigations regarding the predictors of negative outcomes and the selection of transcatheter aortic valve replacement candidates, the use of cardiac-gated computed tomography should be stimulated and promoted as a valuable aid for the diagnosis and further clinical decision making in those patients.

TAVR vs SAVR: Rising Expectations and Changing Indications for Surgery in Response to PARTNER II.

Despite the criticisms and concerns raised on the data published in the PARTNER II trial and related analyses, we are undeniably witnessing a revolution in the management of aortic valve disease, in which conventional full sternotomy surgical aortic valve replacement (SAVR), with all related complications and clinical burden, will soon become a nonviable option. Several of the findings described in the PARTNER II trial, although considerable as points of incongruence and study biases in comparison with SAVR, could be taken as lessons to found a new course in SAVR and redesign the respective roles of surgery and interventional procedures in aortic disease. In particular, the results of these trials can actually be considered as a stimulus to invest more effort to improve the current surgical practice that should embrace alternative solutions and least invasive approaches to provide a competitive advantage over percutaneous procedures. An analysis of these points in light of the more recent findings on transcatheter valve durability, thrombosis, and postprocedural complications is provided. Considerations on the parallel progress of SAVR and on the need for a behavioral change in the surgical community are discussed.

Coronary Artery Calcium Score Improves the Prediction of Occult Coronary Artery Stenosis in Ischemic Stroke Patients.

BACKGROUND: Coronary heart disease is a significant cause of morbidity and mortality in stroke patients. The coronary artery calcium score (CACS) has emerged as a robust and noninvasive predictor of coronary events. We assessed the predictive ability of CACS to identify stroke patients with severe (≥50%) occult coronary artery stenosis in a stroke/transient ischemic attack population, in addition to the PRECORIS score, based on Framingham Risk Score and presence of cervicocephalic artery stenosis, which was derived and validated for that purpose. METHODS AND RESULTS: We enrolled consecutive patients aged 45 to 75 years referred to our stroke unit with noncardioembolic ischemic stroke or transient ischemic attack, and no prior history of coronary disease. The presence of coronary stenosis was assessed with 64-section computed tomography coronary angiography, and all patients had a detailed etiological work-up. CACS was determined from computed tomography measurement using the Agatson score. The predictive value of CACS was assessed by logistic regression and reclassification method. Among 300 patients included in the study, 274 had computed tomography coronary angiography. Fifty patients (18%) had at least 1 coronary artery stenosis ≥50%. In multivariable analysis, after adjustment for the PRECORIS score, CACS was strongly associated with the presence of occult coronary artery stenosis (odds ratio=14.8 [1.8-120.3] for CACS [1-100] and 70.9 [8.9-562.0] for CACS >100). When CACS was added to the standard model, model fit was improved (P<0.001), Net Reclassification Improvement was 28.2% (P<0.001), and Integrated Discrimination Index was 18.2% (P<0.001). CONCLUSIONS: In stroke/transient ischemic attack patients, CACS improves the prediction of occult coronary stenosis beyond classical risk factors.

Pushing the Limits in Transcatheter Aortic Valve Replacement: High-Volume Center's Effect, Overconfidence, or Something Else?

The recent literature on transcatheter aortic valve replacement (TAVR) is shedding new light on the perspective to extend this procedure to other lower risk-category of patients, leading in fact to a potential erosion of the current guidelines. Notwithstanding the warnings provided in the literature regarding the risk of severely impairing complications, unclear survival advantage, and cost-inefficiency, many observational studies, especially performed in high-volume centers, support a general drive toward the recruitment of intermediate-low risk patients in the expectation of clinical advantages versus standard surgical replacement. It appears that, in combination with the development of more refined technologies, medical groups with matured experience and centers able to successfully manage patients with different profiles have been progressively "selected" and emerged pushing further the limits of the procedure itself. On the surgeon side, involved in the surgical assistance of TAVR procedures or in the standby-coverage in case of major complications, the expansion of indications and the interventionists' overconfidence have relevant implications. Considerations on the actual long-term effectiveness of the procedure on younger lower-risk patients in terms of actual hemodynamic durability and inability to deal with functional and morphological aspects of annular calcifications should be made. Also, it seems that other technologies enabling annulus decalcification, such as sutureless valve, have been totally overlooked and trials sponsored by industrial leaders in the market have taken the lead. Such a rapid expansion of TAVR indications should be better understood considering that in the surgical field valve bioprostheses needed to undergo a much longer validation period and the appearance of data on their 20 years follow-up after implantation was required before the application in younger patients.

Predicting asymptomatic coronary artery disease in patients with ischemic stroke and transient ischemic attack: the PRECORIS score.

BACKGROUND AND PURPOSE: Identifying occult coronary artery stenosis may improve secondary prevention of stroke patients. The aim of this study was to derive and validate a simple score to predict severe occult coronary artery stenosis in stroke patients. METHODS: We derived a score from a French hospital-based cohort of consecutive patients (n=300) who had an ischemic stroke or a transient ischemic attack and no previous history of coronary heart disease (Predicting Asymptomatic Coronary Artery Disease in Patients With Ischemic Stroke and Transient Ischemic Attack [PRECORIS] score) and validated the score in a similar Korean cohort (n=1602). In both cohorts, severe coronary artery stenosis was defined by the presence of at least 1≥50% coronary artery stenosis as detected by 64-section CT coronary angiography. RESULTS: A 5-point score (Framingham Risk Score-predicted 10-year coronary heart disease risk [≥20%=3; 10-19%=1; <10%=0] and cervicocephalic artery stenosis [≥50%=2; <50%=1; none=0]) was predictive of occult≥50% coronary artery stenosis risk in the derivation cohort (C-statistic=0.77 [0.70-0.84]) and in the validation cohort (C-statistic=0.66 [0.63-0.68]). The predictive ability of the score was even stronger when only ≥50% left main trunk disease or 3-vessel disease were considered (C-statistic=0.83 [0.74-0.92] and 0.70 [0.66-0.74] in derivation and validation cohorts, respectively). The prevalence of occult≥50% coronary artery stenosis and ≥50% left main trunk or 3-vessel disease increased gradually with the PRECORIS score, reaching 44.2% and 13.5% in derivation cohort and 49.8% and 12.8% in validation cohort in patients with a PRECORIS score≥4. CONCLUSIONS: The PRECORIS score can identify a population of stroke or transient ischemic attack patients with a high prevalence of occult severe coronary artery stenosis.

Aortic stiffness measurement improves the prediction of asymptomatic coronary artery disease in stroke/transient ischemic attack patients.

BACKGROUND: Aortic stiffness is an independent predictor of coronary events. AIMS: We assessed the predictive value of aortic stiffness for ≥50% asymptomatic coronary artery disease in a stroke/transient ischemic attack population. METHODS: We enrolled 300 consecutive patients aged 45-75 years with nondisabling, noncardioembolic ischemic stroke or transient ischemic attack, and no prior history of coronary artery disease. Coronary artery disease was assessed with 64-section computed tomography coronary angiography and all patients had a detailed cervicocephalic arterial work-up. Aortic stiffness was determined from carotid-femoral pulse wave velocity with 9.6 m/s as cutoff value. The predictive value of aortic stiffness was assessed by logistic regression and reclassification tables method after adjustment for the Framingham Risk Score and the presence of cervicocephalic stenosis, which were previously shown to be independent predictor of ≥50% asymptomatic coronary artery disease. RESULTS: Among the 274 included patients who had computed tomography coronary angiography, 26% (95% CI, 21%-32%) had an increased stiffness (pulse wave velocity > 9.6 m/s) and 18% (14%-23%) had ≥50% asymptomatic coronary artery disease. Increased aortic stiffness was associated with the presence of ≥50% asymptomatic coronary artery disease, both in univariate (odds ratio = 3.4 [1.8-6.4]) and multivariate analyses (odds ratio = 2.3 [1.2-4.7]) after adjustment for Framingham Risk Score and presence of cervicocephalic stenosis. After carotid-femoral pulse wave velocity was added to the standard model including Framingham Risk Score and the presence of cervicocephalic stenosis, net reclassification improvement was 12.6% (P < 0.005), integrated discrimination index was 2.51% (P = 0.025), and model fit was improved (likelihood ratio = 4.99, P = 0.025). CONCLUSIONS: In stroke/transient ischemic attack patients, aortic pulse wave velocity improves the prediction of ≥50% asymptomatic coronary artery disease beyond classical risk factors.

Septic rupture of an atherosclerotic plaque of the ascending aorta.

Infectious aortitis has become a rare disease thanks to the widespread use of antibiotics. We report the case of a patient who, 15 days after initiation of antibiotics for bacteraemia due to methicillin-resistant Staphylococcus aureus (MRSA), developed acute chest pain followed by haemodynamic instability. A tamponade due to a rupture into the pericardium of the ascending aorta at the site of an atherosclerotic plaque was diagnosed by an emergent chest contrasted computed tomography (CT). Intraoperatively, the septic nature of the rupture was suspected. All aortic atherosclerotic plaque samples grew MRSA. Postoperatively, the patient had an uneventful recovery after 12 weeks of antibiotic therapy. Transoesophageal echocardiography and chest CT were normal at 3 months after cessation of antibiotics. This case report permits the review of some characteristics of this disease, its physiopathology as well as the therapeutic implications.

Prevalence of asymptomatic coronary artery disease in ischemic stroke patients: the PRECORIS study.

BACKGROUND: Coronary artery disease (CAD) is a significant cause of morbidity and mortality in stroke patients. Some patients with asymptomatic CAD might benefit from specific prevention, but the prevalence of asymptomatic CAD is not well known. We assessed the prevalence of >or=50% asymptomatic CAD in patients with ischemic stroke or transient ischemic attack and whether the prevalence is related to traditional vascular risk factors and cervicocephalic atherosclerosis. METHODS AND RESULTS: From January 2006 to February 2009, consecutive patients between 45 and 75 years of age with nondisabling, noncardioembolic ischemic stroke or transient ischemic attack and no prior history of CAD were enrolled in the study. All patients had a 64-section computed tomography coronary angiography and a detailed cervicocephalic arterial workup. Risk factors were assessed individually and through the Framingham Risk Score. Among 300 patients included in the study, 274 had computed tomography coronary angiography. The prevalence of >or=50% asymptomatic CAD was 18% (95% confidence interval [CI], 14 to 23; n=50). Asymptomatic CAD was independently associated with traditional risk factors assessed individually and through the Framingham Risk Score (odds ratio [OR], 2.6; 95% CI, 1.0 to 7.6 for a 10-year risk of coronary heart disease of 10% to 19%; and OR, 7.3; 95% CI, 2.8 to 19.1 for a 10 year-risk of coronary heart disease >or=20%), the presence of at least 1 >or=50% cervicocephalic artery stenosis (OR, 4.0; 95% CI, 1.4 to 11.2), excessive alcohol consumption (OR, 3.1; 95% CI 1.3 to 7.3), and ankle brachial index <0.9 (OR, 2.2; 95% CI, 0.9 to 5.2). The prevalence of >or=50% asymptomatic CAD was also related to the extent of cervicocephalic atherosclerosis. CONCLUSIONS: About one fifth of patients with nondisabling, noncardioembolic ischemic stroke or transient ischemic attack have >or=50% asymptomatic CAD. In addition to vascular risk factors, the presence of >or=50% cervicocephalic artery stenosis is strongly related to >or=50% asymptomatic CAD.

Coronary artery stenosis in high-risk patients: 64-section CT and coronary angiography--prospective study and analysis of discordance.

PURPOSE: To assess the diagnostic accuracy of multisection (64-section) computed tomography (CT) versus coronary angiography in detection of and assignment of grades for coronary artery stenoses in a high-risk population and to investigate causes for discordance between the two. MATERIALS AND METHODS: The protocol was approved by the local ethics committee. Patients gave informed consent. The study included 114 patients (103 men, 11 women; mean age, 63 years +/- 8.2 [standard deviation]) with potential myocardial ischemia. Multisection CT images were interpreted independently by two radiologists with unequal experience in reading coronary CT angiograms. Diagnostic performance of 64-section CT in detection of stenoses of 50% or more was assessed per patient, per artery, and per segment. Interrater agreement was assessed by using the Cohen kappa coefficient. Agreement between 64-section CT and coronary angiography for assigning grades to stenoses was assessed by using Bland-Altman analysis. RESULTS: Sixty-eight percent of patients had stenoses of 50% or more. Good interrater agreement was found, with kappa values of 0.77-0.85. For the most experienced radiologist, the sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were 73.4%, 95.0%, 14.7, and 0.28 per segment, 95.2%, 94.7%, 18.0, and 0.05 per artery, and 100%, 89.2%, 9.26, and zero per patient, respectively. Discordance between 64-section CT and coronary angiography was related to either under- or overestimation of the degree of stenosis, anatomic misclassification, and coronary artery segments that were not assessable at 64-section CT. Bland-Altman analysis showed poor agreement, especially for intermediate stenosis (mean bias, 1.3%; 95% limits of agreement: -27.3%, 29.9%). CONCLUSION: Despite excellent sensitivity and negative likelihood ratios in a per-patient or per-vessel analysis, some coronary artery stenosis remained misdiagnosed with 64-section CT, resulting in limited sensitivity on a per-segment basis owing to anatomic discordance and failure to accurately quantify intermediate stenosis.

Coronary computed tomography angiography: overview of technical aspects, current concepts, and perspectives.

Multidetector-row electrocardiogram (ECG)-gated cardiac computed tomography (CT) will probably be a major noninvasive imaging option in the near future. Recent developments indicate that this new technology is improving rapidly. This article presents an overview of the current concepts, perspectives, and technical capabilities in coronary CT angiography (CTA). We have reviewed the recent literature on the different applications of this technology; of particular note are the many studies that have demonstrated the high negative predictive value (NPV) of coronary CTA, when performed under optimal conditions, for significant stenoses in native coronary arteries. This new technology's level of performance allows it to be used to evaluate the presence of calcified plaques, coronary bypass graft patency, and the origin and course of congenital coronary anomalies. Despite a high NPV, the robustness of the technology is limited by arrhythmias, the requirement of low heart rates, and calcium-related artifacts. Some improvements are needed in the imaging of coronary stents, especially the smaller stents, and in the detection and characterization of noncalcified plaques. Further studies are needed to more precisely determine the role of CTA in various symptomatic and asymptomatic patient groups. Clinical testing of 64-slice scanners has recently begun. As the technology improves, so does the spatial and temporal resolution. To date, this is being achieved through the development of systems with an increased number of detectors and shorter gantry rotation time, as well as the development of systems equipped with 2 X-ray tubes and the eventual development of flat-panel technology. Thus further improvement of image quality is expected.

Diagnosis of aortic valvular stenosis by multislice cardiac computed tomography.

AIMS: Current improvements in spatial, temporal, and contrast resolution of multislice computed tomography (CT) could be useful in the assessment of valvular diseases. We evaluated the diagnostic accuracy of multislice CT for the identification and quantification of aortic valvular stenosis (AS), compared with echography. METHODS AND RESULTS: Consecutive patients, referred for coronary CT, were evaluated for AS, by the use of standard electrocardiography-gated 16-slice CT protocol. Multiplanar reformat was applied to systolic phases of the cardiac cycle, with projection on thick slices for measuring the aortic valvular area (AVA). CT results were compared with echocardiographic-based measurement of the AVA. Among 107 enrolled patients, CT analysis of the AVA was feasible in 103. Among the 30 patients with AS, Bland-Altman analysis showed good agreement between the two methods [mean difference -7 mm(2) (-40-25 mm(2))]. CONCLUSION: CT analysis of aortic valve is feasible in most cases and allows for reliable diagnosis and quantification of AS.

New trends in non-invasive coronary angiography with multislice CT.

Recent trends in computed tomography (CT) scanner technology has opened new frontiers in the field of non-invasive coronary angiography. Given the relatively important number of negative invasive angiographies performed each year, eliminating the risks inherent to this procedure by non-invasive methods greatly contribute to diminishing the risk. After injection of contrast, the procedure is performed under short apnea and triggered by electrocardiographic (ECG) recording that provides a multitude of possible image reconstructions; ie, volume rendering, virtual angioscopy, and three-dimensional (3D) reconstruction of the heart and coronary vessels. In 100 patients, adequate visualisation of the coronary arteries was achieved in 98%, with the advantage of visualizing the coronary wall as well as the lumen. The main reasons for failure were arrhythmia and excessive motion. Besides evaluating coronary artery atherosclerosis, computed tomography angiography (CTA) allowed the diagnosis of coronary aneurysm and exact localization of postoperative false aneurysm. The main disadvantages of the technique are the absence of dynamic films and exposure to radiation. The increased accuracy and sensitivity of noninvasive coronary angiography make it an excellent diagnostic tool and a probable replacement to invasive procedures. It should reduce the morbidity and mortality as well as the cost of conventional coronary arteriography. Furthermore, it has the added benefit of offering spacial resolution of the examined vessels.