Caution: Air Embolism Related to Heli-Fx EndoAnchor System in Zone 2 Thoracic Aneurysm Repair

PURPOSE

We report a case of significant air embolization to the ascending aorta immediately following deployment of EndoAnchors in the aortic arch during a procedure to correct a type 1A endoleak.

CASE REPORT

The novel Heli-Fx EndoAnchor system (Medtronic Vascular, Santa Rosa, CA, USA) was used to deploy helical anchors in the distal aortic arch during a procedure to correct a type 1A endoleak following Zone 2 thoracic endovascular aortic repair of a saccular proximal descending thoracic aorta aneurysm (DTAA). The patient developed ST-segment elevations principally in the inferior leads and severe hypotension moments after EndoAnchor deployment at the proximal edge of the endograft. Transesophageal echocardiogram revealed severe right ventricular hypokinesis and a large amount of air in the ascending aorta. Subsequent management and clinical and radiological 30-day follow-up is presented in addition to a review of the literature and ex vivo testing with the Heli-Fx system to examine potential causes and solutions.

CONCLUSION

Precautions, such as pressurized saline infusion to the side port of guiding sheath, should be used whenever manipulating catheters and sheaths such as the EndoAnchor system in the aortic arch to prevent this potentially lethal complication.

Percutaneous Treatment of Concomitant Severe Aortic Stenosis and Thoracoabdominal Aortic Aneurysm

PURPOSE

Although rare in occurrence, symptomatic severe aortic stenosis and large thoracoabdominal aortic aneurysm (TAAA) found in combination pose a real therapeutic challenge, especially in elderly frail patients. Surgical approaches for combined treatment are complex and at high risk of complications while staged procedures carry the risk of an unfavorable evolution of the condition temporarily left untreated. Minimally invasive approaches may therefore prove a more suitable strategy for these patients.

CASE REPORT

We present the case of a 78-year-old woman with symptomatic severe aortic stenosis (AS) and a TAAA of 7.8 cm in diameter. Transcatheter treatment of both conditions was successfully performed in a staged manner. The first intervention consisted of combined transfemoral transcatheter aortic valve implantation (TAVI) immediately followed by a zone 3 thoracic endovascular aortic endoprosthesis deployment. In order to reduce the extent of intercostal arteries coverage and mitigate the risk of medullar ischemia, a second-stage percutaneous endovascular treatment of the TAAA was performed with a customized 4-fenestration prosthesis. Early and 12-month clinical and radiologic follow-up were favorable.

CONCLUSION

This case demonstrates how a strong multidisciplinary collaboration allows for successful resolution of complex clinical scenarios.

Anatomic and procedural determinants of fluoroscopy time during elective endovascular aortic aneurysm repair

Objective

To identify both the procedural and anatomic factors which determine duration of fluoroscopy during elective endovascular aortic aneurysm repair (EVAR).

Methods

We retrospectively analyzed our prospectively maintained EVAR database for the relationship between fluoroscopy time and both procedural (type of graft, configuration, number of components, surgeon) and anatomic factors reflective of aneurysm complexity (15 variables).

Results

A total of 128 patients underwent elective EVAR with a mean fluoroscopy time of 5.7 ± 3.4 min. The type of grafts used consisted of 41 (32%) Zenith, 85 (66.4%) Endurant and 2 (1.6%) Anaconda, with 105 (82%) being bifurcated and 23 (18%) being aorto-uni-iliac (AUI) in configuration. Both the surgeon performing the procedure ( p = 0.001) and graft configuration (bifurcated vs. AUI, p = 0.03) were found to be predictive of fluoroscopy time; while procedural and anatomic variables were not.

Conclusions

The surgeon’s efficiency in the use of fluoroscopy during EVAR is the most important determinant of total fluoroscopy time. Anatomic complexity, make of device, and number of components inserted have minimal impact on duration of fluoroscopy. An endovascular surgeon’s ability to curtail fluoroscopy duration is the key component in minimizing radiation exposure to both the surgical team and the patient.

Cell Specificity of Aquaporins 0, 3, and 10 Expressed in the Testis, Efferent Ducts, and Epididymis of Adult Rats

Aquaporins (AQPs) are transmembrane protein channels that allow the rapid passage of water across an epithelium at a low energy requirement, though some also transport glycerol, urea, and solutes of various sizes. At present, 11 members of the AQP family of proteins have been described in mammals, with several being localized to the testis (AQP-7 and AQP-8), efferent ducts (AQP-1 and AQP-9), and epididymis (AQP-1 and AQP-9) of adult rats. With the discovery of expression of multiple AQPs in different tissues, we undertook a systematic analysis of several other members of the AQP family on Bouin-fixed tissues of the male reproductive tract employing light microscope immunocytochemistry. In the testis, AQP-0 expression in the seminiferous epithelium was restricted to Sertoli cells and to Leydig cells of the interstitial space; no reaction was observed in the efferent ducts or epididymis. In Sertoli cells, a semicircular pattern of staining was noted, with only one fourth or one half of the Sertoli cells of a given tubule showing a reaction product. Furthermore, while Sertoli cells at stages VI-VIII of the cycle showed intense staining, those at stages IX-XIV were least reactive, with Sertoli cells at stages I-V showing intermediate levels of reaction product. The epithelial expression of AQP-10 was restricted to the microvilli of the nonciliated cells and the cilia of the ciliated cells of the efferent ducts; however, the endothelial cells of vascular channels of the efferent ducts and epididymis were also intensely reactive. AQP-3 expression was localized exclusively to the epididymis, where intense staining was noted exclusively over basal cells. Examination of orchidectomized rats revealed that AQP-3 expression was abolished over basal cells and that it was greatly diminished after efferent duct ligation. As the reaction was not fully restored in orchidectomized animals supplemented with high levels of testosterone, we suggest that AQP-3 expression in basal cells is regulated in part by testosterone, in addition to a luminal factor emanating from the testis. Together, the data indicate a cell- and tissue-specific expression for AQP-0, AQP-3, and AQP-10 in the testis, efferent ducts, and epididymis, as well as differential regulating factors for the expression of AQP-3 in basal cells.

Expression of aquaporins in the efferent ductules, sperm counts, and sperm motility in estrogen receptor-alpha deficient mice fed lab chow versus casein

Estrogens play an important role in the male reproductive tract, and this is especially so for the efferent ductules, where alpha-estrogen receptors (ERalpha) have been localized. Mice deficient in ERalpha (alphaERKO mice) are infertile, and the effect appears to be due in part to retention of water at the level of the efferent ductules. In the present study, we examined the consequences of ERalpha deletion on the distribution of certain aquaporins (AQPs), water protein channels, in the efferent ductules and on sperm numbers and motility. In addition, the effects of feeding mice a regular lab chow diet, which contains phytoestrogens, known to affect male reproductive tract functions, and a casein diet, which lacks phytoestrogens, were also assessed. Light microscope immunolocalizations of AQP-1 and AQP-9 revealed dramatic reduction and patchier staining in alphaERKO mice with distal areas of the efferent ductules being more affected than proximal areas. No other changes in immunolocalizations were noted as a consequence of diet. Computer-assisted sperm analyses demonstrated a 62% reduction in cauda epididymal sperm/ml in alphaERKO mice fed lab chow, whereas 87% fewer sperm/ml were observed in alphaERKO mice fed casein, suggesting an enhanced role for sperm production and concentration in a diet containing phytoestrogens. All sperm motility parameters were altered to some degree in alphaERKO mice fed lab chow. Alterations in sperm motility parameters were also detected, but were less dramatic in alphaERKO mice fed casein. These data suggest that the decrease in AQP expression in the efferent ductules of alphaERKO mice contributes in part to water retention in this tissue, eventually leading to backflow of water into the testis, with subsequent decreases in sperm concentration and motility. The data also suggest that phytoestrogens, which are present in regular lab chow, can influence the male reproductive tract with and without the presence of ERalpha, promoting efferent ductule and epididymal functions when ERalpha is expressed, but inhibiting these same functions when ERalpha is missing. Taken together the data underscore the importance of estrogens and ERalpha in maintaining sperm maturation and preventing male infertility.

Immunolocalization and regulation of cystic fibrosis transmembrane conductance regulator in the adult rat epididymis

Cystic fibrosis is the most common serious autosomal recessive condition in whites, and more than 95% of men with cystic fibrosis are infertile. The cystic fibrosis transmembrane conductance regulator (CFTR), a cyclic adenosine monophosphate (cAMP)-regulated chloride channel, has been localized in the efferent ducts; however, to our knowledge, its expression and regulation in the epididymis by testicular factors have not been examined. In the present study, these parameters were examined immunocytochemically by the light microscope with an anti-CFTR antibody in Bouin-fixed, paraffin-embedded control adult rat epididymides and both orchidectomized adult rats with or without testosterone supplementation and efferent duct-ligated rats sacrificed at different time points. In control animals, a thick dense band of immunoperoxidase reaction product was visualized over the apical plasma membrane of the principal cells but not their microvilli. The apical band was prominent only in the corpus and cauda regions. While there was no CFTR expression in basal cells, clear cells of the corpus and cauda regions showed a weak-to-moderate band of apical plasma membrane staining. An examination of orchidectomized, orchidectomized and testosterone, and efferent duct-ligated rats revealed that CFTR was no longer expressed as an intense band on the apical plasma membrane of the principal cells of the corpus and cauda regions. However, under these conditions, an intense apical/supranuclear reaction was noted in the form of small vesicular structures. Clear cells were unaffected by the different experimental treatments. Together, these data indicate that CFTR is expressed in a cell- and region-specific manner and that, while its synthesis in principal cells is not under the control of testicular factors, targeting to the apical plasma membrane is regulated by a testicular luminal factor.