Can silicone models replace animal models in hands-on training for endovascular stroke therapy?

PURPOSE

Since thrombectomy has become a standard treatment technique for stroke, there is great demand for well-trained interventionalists. We offer practical courses on both silicone models and porcine models, and conducted a survey to evaluate whether ex vivo training models could replace in vivo models in the future.

METHODS

In total, 110 neurointerventionalists participating in 30 training courses were included in our survey using a semi-structured questionnaire.

RESULTS

The level of experience in thrombectomy maneuvers was almost balanced in our sample (52% experienced and 48% less-experienced participants). Silicone models were regarded as useful training tools regardless of the participants' experience (p = 1.000): 94% of less-experienced and 92% of experienced participants considered a silicone model to be a useful introduction for training with animal models. Of the participants, 95% indicated that training on animal models was helpful and necessary, even if they already had experience in performing interventions in humans (p = 1.000). After joining this course, 97% of all participants felt well prepared to perform thrombectomies in humans.

CONCLUSION

Even experienced participants benefit from silicone models. Silicone models are a good preparation for animal models but cannot replace them. Categorizing participants depending on their experience and their individual needs before practical training may allow for more efficient endovascular training.

Infection risk in endovascular neurointerventions: a comparative analysis of 549 cases with and without prophylactic antibiotic use

OBJECTIVE

A systematic analysis on the utility of prophylactic antibiotics for neuroendovascular procedures has not been performed. At the authors' institution there is a unique setup to address this question, with some attending physicians using prophylactic antibiotics (cefazolin or vancomycin) for all of their neurointerventions while others generally do not.

METHODS

The authors performed a retrospective review of the last 549 neurointerventional procedures in 484 patients at Tisch Hospital, NYU Langone Medical Center. Clinical and radiological data were collected for analysis, including presence of prophylactic antibiotic use, local or systemic infection, infection laboratory values, and treatment. Overall, 306 aneurysms, 117 arteriovenous malformations/arteriovenous fistulas, 86 tumors, and 40 vessel stenosis/dissections were treated with coiling (n = 109), Pipeline embolization device (n = 197), embolization (n = 203), or stenting (n = 40).

RESULTS

Antibiotic prophylaxis was used in 265 of 549 cases (48%). There was no significant difference between patients with or without antibiotic prophylaxis in sex (p = 0.48), presence of multiple interventions (p = 0.67), diseases treated (p = 0.11), or intervention device placed (p = 0.55). The mean age of patients in the antibiotic prophylaxis group (53.4 years) was significantly lower than that of the patients without prophylaxis (57.1 years; p = 0.014). Two mild local groin infections (0.36%) and no systemic infections (0%) were identified in this cohort, with one case in each group (1/265 [0.38%] vs 1/284 [0.35%]). Both patients recovered completely with local drainage (n = 1) and oral antibiotic treatment (n = 1).

CONCLUSIONS

The risk of infection associated with endovascular neurointerventions with or without prophylactic antibiotic use was very low in this cohort. The data suggest that the routine use of antibiotic prophylaxis seems unnecessary and that to prevent antibiotic resistance and reduce costs antibiotic prophylaxis should be reserved for selected patients deemed to be at increased infection risk.

Endovascular neurointervention success and complication rates in the first year of independent practice in a suburban hospital setup

CONTEXT

Endovascular neurointervention (interventional neuroradiology) is a highly demanding science requiring deep understanding of disease, anatomy, clinical skills and manual dexterity, consequently with a long learning curve and thus posing significant challenges to a physician entering new into the competitive arena.

AIM

To evaluate the procedural success, complications and outcome in the first year of independent endovascular neurointervention practice in a suburban hospital.

MATERIALS AND METHODS

Retrospective analysis of prospectively maintained data of all diagnostic and therapeutic neurointerventional cases performed by the author between the period of January 02, 2012 and December 31, 2012.

RESULTS

A total of 61 procedures were performed. The performance success rate of the diagnostic procedures was 100% (38/38) and that of therapeutic procedures was 82.6% (19/23). The periprocedural complication rates were nil and 13%, respectively, for diagnostic and therapeutic procedures. The 3-month patient outcome for therapeutic procedures was good outcome (Modified Rankin Scale <2) in 87% cases (20/23), and poor outcome in 13% (2 dead and 1 debilitated with Modified Rankin Scale of 3).

CONCLUSION

For a well-trained endovascular neurointerventionalist, the first year of practice had high procedural success rate and acceptable complication with patient outcome rates comparable to the existing literature.

Deuterium oxide as a contrast medium for real-time MRI-guided endovascular neurointervention

Rationale: Endovascular intervention plays an important role in the treatment of various diseases, in which MRI-guidance can potentially improve precision. However, the clinical applications of currently available contrast media, including Gadolinium-based contrast agents and superparamagnetic iron oxide particles (SPIO), are hindered by safety concerns. In the present study, we sought to develop D2O as a novel contrast agent for guiding endovascular neurointervention. Methods: Animal studies were approved by institutional ACUC and conducted using an 11.7 T Bruker Biospec system and a 3T Siemens Trio clinical scanner for rodent and canine imaging, respectively. The locally selective blood brain barrier opening (BBBO) in rat brains was obtained by intraarterial (IA) injection of mannitol. The dynamic T2w* EPI MRI sequence was used to study the trans-catheter perfusion territory by IA administered SPIO before mannitol administration, whereas a dynamic T1w FLASH sequence was used to acquire Gd contrast-enhanced MRI for assessing BBBO after injection of mannitol. The contrast generated by D2O assessed by either EPI or FLASH methods was compared with the corresponding results assessed by SPIO or Gd. The utility of D2O MRI was also demonstrated to guide drug delivery to glioma in a mouse model. Finally, the clinical utility of D2O-MRI was demonstrated in a canine model. Results: Our study has shown that the contrast generated by D2O can be used to precisely delineate trans-catheter perfusion territory in both small and large animals. The perfusion territories determined by D2O-MRI show moderate correlation with those by SPIO-MRI (Spearman coefficient r = 0.5234, P < 0.001). Moreover, our results show that the perfusion territory determined by D2O-MRI can successfully predict the areas with BBBO after mannitol treatment similar to that assessed by Gd-MRI (Spearman coefficient r = 0.6923, P < 0.001). Using D2O-MRI as imaging guidance, the optimal infusion rate in the mouse brain was determined to be 150 µL/min to maximize the delivery efficacy to the tumor without serious off-target delivery to the brain parenchyma. The enhanced drug delivery of antibodies to the brain tumor was confirmed by fluorescence imaging. Conclusion: Our study demonstrated that D2O can be used as a negative MRI contrast medium to guide endovascular neurointervention. The established D2O -MRI method is safe and quantitative, without the concern of contrast accumulation. These qualities make it an attempting approach for a variety of endovascular procedures.