Early experience with bridging stent graft deployment without sheath support in branched and fenestrated endovascular aortic repair

OBJECTIVE

To assess the early experience with modified version of simplified bare-wire target vessel (SMART) technique, implying delivery of bridging stent grafts without historically established sheath support, and to compare its outcome to standard endovascular aortic repair procedures with fenestrated/branched devices.

METHODS

A retrospective analysis of 102 consecutive patients treated with fenestrated/branched devices from January 2020 to December 2022 was undertaken. The study population was divided into three groups-a sheath group (SG), SMART group, and nonsheath group (NSG). Primary end points were radiation exposure (dose-area product), fluoroscopy time, dose of contrast agent, operation time, and incidence of intraoperative target vessel (TV) complications and additional procedures. Freedom from secondary TV related reinterventions at the three follow-up phases were defined as secondary end points.

RESULTS

A total of 183 TVs (38.8% visceral arteries [VA]; 56.3% renal arteries [RA]) in the SG, 36 TVs (44.4% VA, 55.6% RA) in the SMART group, and 168 TVs (47.6% VA; 50% RA) in the NSG were accessed. The mean number of fenestrations and bridging stent grafts was equally distributed in all three groups. The SMART group only included cases treated with fenestrated devices. The dose-area product was significantly lower in the SMART (median, 203 Gy × cm2; interquartile range [IQR], 179-365 Gy × cm2) and NSG (median, 340 Gy × cm2; IQR, 220-651 Gy × cm2) groups vs the SG (median, 464 Gy × cm2; IQR, 267-871 Gy × cm2; P = .007). Operation time was also significantly lower in the NSG (median, 265 minutes; IQR, 221-337 minutes) and SMART (median, 292 minutes; IQR, 234-351 minutes) groups vs the SG (median, 326 minutes; IQR, 277-375 minutes; P = .004), respectively. Intraoperative TV-related complications were most frequently observed in the SG (9/183 TVs; P = .008).

CONCLUSIONS

This study reports the outcomes of three currently available TV stenting approaches. Previously reported SMART technique, and its modified version (NSG) proved to be a safe alternative to historically established TV stenting technique with sheath support (SG).

Endovascular repair in type A aortic dissection: Anatomic candidacy for currently manufactured stentgrafts and conceptual valve-carrying devices for an Endo-Bentall procedure

OBJECTIVES

Endovascular treatment has been suggested as alternative for open surgery as treatment for type A aortic dissection, but current devices have severe anatomic limitations. This study assesses computed-tomography-based anatomic suitability of currently manufactured stent grafts as well as two embodiments of valve-carrying devices.

METHODS

In a retrospective single-center cohort of 200 consecutive ascending/arch operations between 2009 and 2018, 112 type A aortic dissection patients were identified and evaluated for endovascular candidacy based on locations of entries, landing zone diameters/lengths and supra-aortic vessel origins according to the anatomical instructions for use criteria of 6 commercially available, (tubular, branched or fenestrated) stentgrafts. Two suggested valve-carrying devices with inner branches or fenestrations for the coronary arteries and branches for the supra-aortic vessels were also evaluated.

RESULTS

The anatomic feasibility for commercial stentgrafts ranged from 4% to 21%. The main limitations was proximal landing zone diameter (considering oversizing <15%) and length due to dilatation and an entry too close to the sinotubular junction. For the valve-carrying conduits, anatomical feasibility was between 31% and 80%. with the main limiting factors the diameter of the aortic annulus and its distance to the coronary arteries.

CONCLUSIONS

Anatomic applicability of currently manufactured stentgrafts for the treatment of type A aortic dissection is mainly limited by the absence of a suitable proximal landing zone in the ascending aorta and might substantially be improved by anchoring in the aortic annulus using a valve-carrying device which employs either fenestrations or branches for the coronary arteries.

Endovascular Repair of Penetrating Thoracic Aortic Ulcers Using Tubular Stent Grafts Versus Stent Grafts With a Proximal Scallop

PURPOSE

In penetrating aortic ulcers (PAUs), limited data support tubular thoracic endovascular aortic repair (TEVAR) as a viable treatment option. For treatment of more proximal PAUs, hybrid approaches and-more recently-scalloped TEVAR (scTEVAR) have been advocated. Outcomes of scTEVAR specifically for PAUs have not yet been reported. This study reports long-term outcomes for tubular and scTEVAR in PAUs and compares the safety profile in both cohorts regarding the significantly more proximal landing zone (LZ) for scTEVAR.

MATERIALS AND METHODS

This single-center retrospective cohort study includes all nonacute patients treated for complicated PAU with scTEVAR and tubular TEVAR. Patient and PAU characteristics as well as procedural success, complication and reintervention rates, and all-cause and aortic mortality were analyzed.

RESULTS

Of 212 TEVAR procedures reviewed, 21 patients with tubular TEVAR and 19 patients with scTEVAR were included. Patient and PAU characteristics were similar, and LZ was significantly more proximal in the scTEVAR cohort (p=0.0001), with similar number and types of supra-aortic revascularization procedures. Clinical success was reached in all 40 patients (100%), and reintervention rate was 2/21 (9.5%) and 1/19 (5.3%), respectively. Over the mean follow-up of 63 (TEVAR) and 53 (scTEVAR) months, clinical success was stable in all patients with one (abdominal) aortic-related mortality in the scTEVAR cohort.

CONCLUSION

Treatment of complicated PAUs with TEVAR as well as scTEVAR provides excellent and similar clinical success, stability of clinical success, and aortic survival with acceptable complication and reintervention rates. Scalloped TEVAR safely lengthens the proximal sealing zone to address more proximal pathologies.

CLINICAL IMPACT

Treatment of asymptomatic complicated penetrating aortic ulcers (PAUs) with thoracic endovascular aortic repair (TEVAR) provides excellent clinical success and acceptable complication and reintervention rates. More patients become amenable to endovascular treatment by including scalloped TEVAR (scTEVAR) as a means to safely lengthen the proximal sealing zone to address more proximal pathologies.

Monoplane versus biplane fluoroscopy in patients undergoing fenestrated/branched endovascular aortic repair

OBJECTIVE

Endovascular aortic repair (EVAR) with fenestrated (F-EVAR) or branched (B-EVAR) endografts represents an indispensable tool of modern patient care in vascular surgery. The purpose of this retrospective study was to evaluate the center's initial experience of F/B-EVAR procedures performed under biplane angiography guidance compared with a historical control group.

METHODS

From January 2020 to March 2022, 80 consecutive patients underwent F/B-EVAR under general anesthesia at a single institution. As from January 2021, the deployment of complex stent grafts was performed using an alternative intraoperative imaging modality-a biplane fluoroscopy and angiography. The cohort was divided into monoplane (MPA) and biplane (BPA) groups according to the imaging modality applied. The end points were operation time, fluoroscopy time, radiation exposure, dose of contrast agent, and technical success.

RESULTS

The MPA group included 59 patients (78% male; median age; 74 years; interquartile range [IQR], 66-78 years) and the BPA group 21 patients (85.7% males; median age, 75 years; IQR, 69-79 years). Operation time (median, 320 minutes; IQR, 266-376 minutes) versus (median, 275 minutes; IQR, 216-333 minutes) was significantly lower in the BPA group (P = .006). The median fluoroscopy time (median, 82 minutes; IQR, 57-110 minutes vs median, 68 minutes; IQR, 54-92 minutes), contrast agent volume applied (median, 220 mL; IQR, 179-250 mL vs median, 200 mL; IQR, 170-250 mL), and radiation dose (dose-area product, median, 413 Gy × cm²; IQR, 249-736 Gy × cm²; vs median, 542 Gy × cm²; IQR, 196-789 Gy × cm²) were similar in both groups. Technical success of 96.6% (57/59 cases) versus 100% (21/21 cases) could be achieved in MPA and BPA group, respectively.

CONCLUSIONS

F/B-EVAR procedures performed under BPA guidance were associated with a significant decrease in operation time.

Applicability of endovascular branched and fenestrated aortic arch repair devices to treat residual type A dissection after ascending replacement

OBJECTIVE

Endovascular repair of post-type-A aortic dissection after open ascending replacement (PTAD) has recently been shown as safe and feasible, but with limited anatomic applicability since only one stent graft was evaluated. We assessed anatomic and clinical applicability of six commercially available branched/fenestrated stent grafts for endovascular repair of PTAD.

METHODS

On postoperative CT-scans of 101 patients, we measured aortic diameter at: sino-tubular junction, supra-aortic vessels (SAV), and descending aorta, as well as the distances between these landmarks along the outer curvature of the arch and the diameters of the SAV. Anatomical applicability was evaluated according to the instructions-for-use, clinical applicability with regard to supra-aortic and iliac arteries. Assessed devices were: Cook aortic double branch; Terumo double branch; Najuta fenestrated; Endospan Nexus; Medtronic Mona LSA; and Gore TAG thoracic branch.

RESULTS

Single devices were anatomically and clinically applicable between 19/101 (Mona LSA) and 83/101 (Najuta) cases. Reasons for rejection varied considerably across devices. With all devices available, anatomical applicability was 97/101 and clinical applicability 95/101. Combinations of a fenestrated and a branched device showed the most favorable clinical applicability for a pair of two devices, ranging from 86/101 to 94/101.

CONCLUSIONS

Anatomical and clinical applicability of endovascular devices for the repair of PTAD is high for fenestrated and branched devices, and very high for the combination of fenestrated and branched devices. Manufacturers should amend specific device requirements for PTAD. Surgeons should emphasize the need for a sufficiently long and straight graft as a potential landing zone.

Fenestrierte und verzweigte endovaskuläre Aortenprothesen

Hintergrund

Komplexe abdominelle aortale Pathologien, welche die Abgänge der Viszeralarterien miterfassen und bei denen kein adäquater proximaler Hals gegeben ist, können heute mittels fortgeschrittener FEVAR/BEVAR-Technik („fenestrated/branched endovascular aneurysm repair“) mit ähnlicher Sicherheit und vergleichbaren Erfolgsraten behandelt werden wie infrarenale Pathologien mit konventionellem EVAR.

Methodische Innovationen und Probleme

Zur Versorgung der Viszeralarterien können Fenestrierungen (bei Abgang der Viszeralarterie aus der nichtdilatierten Aorta) oder Verzweigungen (bei Abgang aus der dilatierten Aorta) verwendet werden. Beide Arten von Öffnungen werden mit Verbindungsstentgrafts (VSG) zu den Viszeralarterien abgedichtet. Mehrere Hersteller bieten fenestrierte oder verzweigte Endoprothesen an, wobei diese nur in Einzelfällen CE-zertifiziert und überwiegend in Europa als individuelle Sonderanfertigungen patientenbezogen erhältlich sind. Dies setzt eine entsprechende Lieferzeit voraus, was die Behandlung akuter Patienten mit solchen Prothesen unmöglich macht. Es liegen allerdings zwei Produkte von vierfach verzweigten Endoprothesen vor, die einen größeren Bereich der anatomischen Gegebenheiten bei thorakoabdominellen Aneurysmen auch im Akutfall abdecken und behandelbar machen. Sämtliche FEVAR- und BEVAR-Hauptkörper benötigen VSG, die durchgehend von Fremdherstellern stammen und von denen gegenwärtig noch kein einziges Produkt für diese Anwendung zertifiziert ist.

Empfehlungen

Da Probleme an Verbindungsstentgrafts eine wesentliche Ursache für Reinterventionen sind, sollte in der Nachsorge Knickbildungen und Brüchen an diesen Verbindungsstents besonderes Augenmerk geschenkt und von der Verwendung einschichtiger Designs beim BEVAR abgesehen werden.

Use of a Steerable Sheath for Completely Femoral Access in Branched Endovascular Aortic Repair Compared to Upper Extremity Access

PURPOSE

To compare bridging stent graft (BSG) implantation in downward oriented branches in branched endovascular aortic repair (bEVAR), using a commercially available steerable sheath from an exclusively femoral access (TFA) with traditional upper extremity access (UEA).

METHODS

In a retrospective cohort study, 7 patients with 19 branches in the TFA cohort received BSG insertion using the Medtronic Heli FX steerable sheath from a femoral access, and 10 patients with 32 branches in the UEA cohort from a brachial approach. Technical success, total intervention time, fluoroscopy time, branch cannulation time, and complication rate were recorded.

RESULTS

Technical success was 19/19 branches in the TFA and 31/32 in the UEA cohort. The mean branch cannulation time was considerably shorter in the TFA group (17 vs. 29 min, p = 0.003), and total intervention time tended to be shorter (169 vs. 217 min, p = 0.176).

CONCLUSION

Using a commercially available steerable sheath allowed successful cannulation of all branches in this cohort and was associated with significantly shorter branch cannulation times. Potentially, this technique can lower the stroke and brachial puncture site complication risk as well as reduce total intervention time and radiation dose.

LEVEL OF EVIDENCE

2b, retrospective cohort study.

Structural failure in bridging stentgrafts for branched endovascular aneurysm repair: a case–control study

Objective

To present a case series of spontaneous structural failure of bridging stentgrafts (BSGs) after branched endovascular aortic repair (bEVAR), as well as their failure types and their detection. While bEVAR is a safe and effective procedure, one main limitation is the reintervention rate associated with the BSGs. Structural failure of BSGs, defined as fabric disruption, stent fracture with leak or complete separation is a major cause for reinterventions and difficult to detect in computed tomography angiography (CTA).

Methods

From a multicenter bEVAR complication database, structural BSG failures were identified. Patient and BSG characteristics, detection mode, failure type, treatment and outcome were recorded and compared with bEVAR patients with intact BSGs.

Results

Twenty-three BSG failures were detected in 12 patients with only 43% directly identified in CTA, after a mean of 21.4 months after implantation. The BSGs were Advanta (n = 4), E-Ventus (n = 16) and BeGraft (n = 3) in 10 renal, 9 superior mesenteric, and 4 celiac branches. Religning with another BSG was successful in 20/22 cases, one BSG failure necessitated renal branch embolization (organ loss), and one mesenteric bypass surgery. Two reintervention-related mortalities occurred.

Conclusion

Structural failure of BSGs is a serious limitation for bEVAR, which can result in high reintervention rates and serious complications. BSG failure typically occurs in single-layer types and events are clustered in patients. The necessary reinterventions carry serious morbidity and mortality. Since the use as BSG in bEVAR is off-label with all current BSG manufacturers, caution is advised regarding patient-informed consent.

Endovascular Stent-Graft Repair of the Ascending Aorta: Assessment of a Specific Novel Stent-Graft Design in Phantom, Cadaveric, and Clinical Application

Purpose

To test a stent-graft specifically designed for the ascending aorta in phantom, cadaver, and clinical application, and to measure deployment accuracy to overcome limitations of existing devices.

Methods

A stent-graft has been designed with support wires to fixate the apices toward the inner curvature, thereby eliminating the forward movement of the proximal end which can happen with circumferential tip capture systems. The device was deployed in three aortic phantoms, and in four cadavers, deployment precision was measured. Subsequently, the device was implanted in a patient to exclude a pseudoaneurysm originating from the distal anastomosis after ascending aortic replacement.

Results

The stent-grafts were successfully deployed in all phantoms and cadavers. Deployment accuracy of the proximal end of the stent-graft was within 1 mm proximally and 14 mm distally to the intended landing zone on the inner curvature, and 2–8 mm distal to the intended landing zone on the outer curvature. In clinical application, the pseudoaneurysm could be successfully excluded without complications.

Conclusion

The novel stent-graft design promises accurate placement in the ascending aorta. The differential deployment of the apices at the inner and outer curvatures allows deployment perpendicular to the aortic axis.

Level of Evidence

No level of evidence.

Novel prefabricated bovine pericardial grafts as alternate conduit for septic aortoiliac reconstruction

OBJECTIVE

Infection of prosthetic aortic grafts represents a serious complication with high morbidity and mortality. Replacement with autologous material is recommended; however, in its absence, biological material should be favored. In the present retrospective cohort study, we evaluated the short- and midterm results with the use of commercially available prefabricated bovine pericardium grafts (BPGs) used for the management of aortic graft infection or aortic reconstructive surgery in the presence of systemic infection.

METHODS

We performed a retrospective analysis of patients in whom BPGs had been used for aortic reconstruction at two vascular centers. Prefabricated vascular pericardium grafts were preferred over other biological reconstruction techniques for selected cases. Comorbidities, procedure-related details, perioperative morbidity, clinical outcomes, and mortality were analyzed.

RESULTS

From 2014 to 2019, 21 patients had received BPGs at two Austrian vascular centers. Their median age was 63 years (interquartile range [IQR], 55-71 years), the patients were predominantly male (76%), and the median body mass index was 25.3 kg/m² (IQR, 21.7-27.3 kg/m²). The major comorbidities included arterial hypertension, peripheral artery disease, smoking, and chronic pulmonary disease. The indications for surgery were vascular graft or endograft infection in 62% and aortic reconstruction in the presence of systemic infection in 38%. Three patients (14%) had aortoenteric fistulas. Surgery was technically successful in all cases. The median follow-up was 21.6 months (IQR, 6.0-34.6 months). The 30-day mortality was 9.5%. The 1- and 2-year overall survival was 84% and 75%, respectively. Of the 21 patients, 89% had remained free of recurrent infection. One of the two reinfections had resolved after treatment of the underlying focus. At 2 years, the primary and assisted primary patency rates were 86% and 94%, respectively. No limbs were lost during follow-up.

CONCLUSIONS

Prefabricated BPGs represent a promising alternative for the management of aortic graft infections and aortoiliac reconstruction in the presence of systemic infection.

Pre-operative serum C-reactive protein as independent prognostic factor for survival but not infection in patients with high-grade osteosarcoma

PURPOSE

The purpose of this study was to investigate (a) whether pre-operative serum CRP is a predictor of survival in patients with high-grade osteosarcoma, (b) whether post-operative infection is a predictor of survival in these patients and (c) whether CRP is a predictor of post-operative infection, and especially deep prosthetic infection.

METHODS

In this retrospective single-centre study, pre-operative serum CRP levels in 79 patients (37 females, 42 males; average age, 18 years; mean follow-up, 46 months) undergoing resection of an osteosarcoma were correlated with clinical data and survival.

RESULTS

The mean pre-operative serum CRP level of all 79 patients was 0.53 mg/dl (SD, 1.27 mg/dl). Patients dying of their underlying disease had significantly higher CRP levels compared to patients surviving throughout the follow-up period (1.09 mg/dl ± 2.02 mg/dl versus 0.32 mg/dl ± 0.75 mg/dl, respectively; p = 0.015). CRP levels were significantly correlated with survival (Pearson's correlation coefficient = -0.25; p = 0.026) and histological subtype (Pearson's correlation coefficient = -0.42; p < 0.001), but not with sex, age, histological response, tumour size or metastatic disease. In uni- and multivariate survival analysis, age, response to chemotherapy and serum CRP were associated with disease-specific survival. Patients with a CRP level over 1 mg/dl had a significantly lower disease-specific five-year survival of 36.7% compared to 73.8% in patients with normal CRP values (p = 0.020). Infection was not correlated with disease-specific survival. Pre-operative serum CRP levels were not correlated with post-operative infection or deep prosthetic infection.

CONCLUSIONS

Pre-operative serum CRP seems to be an independent predictor of survival in patients with high-grade osteosarcoma. Further studies are needed to confirm these results on a large-scale basis.

Colonic adenocarcinomas: near-infrared microcatheter imaging of smart probes for early detection--study in mice

PURPOSE

To prospectively evaluate the ability of micro-fiberoptic catheters, which simultaneously record white light and near-infrared (NIR) images, to reveal colonic neoplasms after the intravenous administration of activatable "smart" probes that increase in NIR fluorescence subsequent to protease activation.

MATERIALS AND METHODS

The institutional animal care committee approved all animal experiments. CT26 tumor cells were orthotopically implanted into the descending colon of C57BL6/J mice (n=10). Thirteen days later, mice intravenously received either 2 nmol of a protease-sensing probe that had cathepsin B as a major activator (n=5) or saline (control animals [n=5]). One day later, animals were noninvasively examined to the point of the splenic flexure by using microcatheter imaging. Excised colons were subsequently evaluated with epifluorescence imaging, histologic examination, and cathepsin B immunohistochemistry. Student t test was used for statistical analysis, with P<.05 considered to indicate a significant difference.

RESULTS

Results with fiberoptic imaging demonstrated that all tumors were visible with the protease-activatable probe, even when they were not readily apparent at white light imaging. A target-to-background ratio (TBR) of 8.86 for tumor to adjacent normal mucosa was achieved in the NIR channel after probe administration (P=.001), whereas white light images resulted in a TBR of 1.14 (P>.5) based on luminosity. The tumoral NIR fluorescence intensity was more than 30-fold greater in probe-injected animals than in control animals, indicating that essentially all of the signal recorded in lesions was from activatable probe administration. Results of immunohistochemistry confirmed cathepsin B overexpression in the tumor compared with adjacent mucosa.

CONCLUSION

The use of NIR imaging microcatheters combined with protease-activatable smart probes results in a beacon effect that highlights tumors with high TBRs; this technique thus may be a potentially useful adjunct to white light colonoscopy in the future.

Simultaneous fluorescence imaging of protease expression and vascularity during murine colonoscopy for colonic lesion characterization

BACKGROUND

Molecularly targeted fluorescent probes are currently being developed to improve the endoscopic detection of intestinal pathologic conditions.

OBJECTIVE

We report on the development and testing of a novel multichannel microendoscope capable of quantitatively reporting such probes simultaneously at different wavelengths in real time. We assessed the feasibility of detecting and quantifying beacons that can be activated by protease and correlating imaging with disease state.

DESIGN

The microendoscope consisted of a 20-gauge fiberoptic catheter and dichroic beam splitters that simultaneously display visible light, 700 nm and 800 nm near infrared (NIR) fluorescent light. NIR interchannel separation was tested on in vitro phantoms. Two mouse models were used (Apcmin(+/-) mice for colonic adenomas and CT26 murine colon cancer). A perfusion probe and one activated by protease at a separate wavelength were injected before endoscopic evaluation.

RESULTS

The microendoscope fluorochrome detection limit was approximately 10 fmol; ratio imaging in the NIR was accurate (+/-8% of true probe concentration between 0.3 to 100 microg/ml of a protease sensor). Both colonic adenomas and adenocarcinomas were clearly visible in the NIR channel on protease probe administration in live mice. Ratio imaging of protease activity/perfusion increased from healthy colon to adenomas to adenocarcinomas.

LIMITATIONS

Evaluation across additional spontaneous tumor models may provide more data on the translation of these findings.

CONCLUSIONS

Our data show the feasibility of multichannel microendoscopic imaging of molecular targets in vivo and that ratio imaging may provide a novel means for characterizing colonic lesions. When scaled up clinically, this could aid in increasing lesion detection and quantitative assessment of distinct molecular markers.

Repeatability and Reproducibility of Central Corneal Thickness Measurement With Pentacam, Orbscan, and Ultrasound

PURPOSE

The purpose of this study was to compare central corneal thickness (CCT) measurements obtained with a novel rotating Scheimpflug camera (Pentacam; Oculus) with scanning slit topography (Orbscan; Bausch & Lomb), and with ultrasound pachymetry (SP-2000; Tomey).

METHODS

CCT in 30 healthy eyes was measured twice with each modality by 2 independent observers in random order. The results from scanning slit topography are given both with and without multiplication with the "acoustic correction factor" of 0.92. In addition, the displayed images from the rotating Scheimpflug camera and scanning slit topography were used to calculate the signal difference-to-noise ratios (SD/N) between cornea and background signal.

RESULTS

The mean CCT values as determined with the different modalities (+/-standard deviation) were: 542+/-29 microm, 576+/-37 microm, 530+/-34 microm, and 552+/-32 microm for rotating Scheimpflug imaging, for uncorrected and for corrected scanning slit pachymetry, and for ultrasound, respectively. The differences between modalities (+/-95% limits of agreement) were -9.8+/-31 microm between rotating Scheimpflug and ultrasound, 24+/-31.2 microm between scanning slit and ultrasound, and 33+/-27 microm between scanning slit and rotating Scheimpflug imaging. The limits of agreement for within and between observer effects were within 4.2% of the absolute CCT values for scanning slit and ultrasound and within 2.2% for the rotating Scheimpflug imaging. The rotating Scheimpflug camera showed similar SD/N ratios but steeper edges of the corneal surfaces in the intensity profile plots.

CONCLUSION

In the assessment of normal corneas, the Pentacam measured CCT values closer to ultrasound pachymetry and with less variability compared with Orbscan. The (interobserver) reproducibility with the Pentacam was highest of all 3 modalities.

MR imaging of the her2/neu and 9.2.27 tumor antigens using immunospecific contrast agents

Molecular imaging of tumor antigens using immunospecific magnetic resonance (MR) contrast agents is a rapidly evolving field, which can potentially aid in early disease detection, monitoring of treatment efficacy, and drug development. In this study, we designed, synthetized, and tested in vitro two novel monocrystalline iron oxide nanoparticles (MION) conjugated to antibodies against the her2/neu tyrosine kinase receptor and the 9.2.27 proteoglycane sulfate. MION was synthetized by coprecipitation of iron II and iron III salts in 12-kD dextran solution; antibody coupling was performed by reductive amination. The relaxivity of the conjugates was 24.1-29.1 mM(-1) s(-1), with 1.8 to 2.1 antibody molecules per nanoparticle. A panel of cultured melanoma and mammary cell lines was used for testing. The cells were incubated with the particles at 16-32 microg Fe/ml in culture medium for 3 h at 37 degrees C, and investigated with immune fluorescence, transmission electron microscopy (TEM), MRI of cell suspensions in gelatine, and spectrophotometric iron determination. All receptor-positive cell lines, but not the controls, showed receptor-specific immune fluorescence, and strong changes in T(2) signal intensity at 1.5 T. The changes in 1/T(2) were between 1.5 and 4.6 s(-1) and correlated with the amount of cell-bound iron (R = 0.92). The relaxivity of cell-bound MION increased to 55.9 +/- 10.4 mM(-1) s(-1). TEM showed anti-9.2.27 conjugates binding to the plasma membrane, while the anti-her2/neu conjugates underwent receptor-mediated endocytosis. In conclusion, we obtained receptor-specific T(2) MR contrast with novel covalently bound, multivalent MION conjugates with anti-9.2.27 and anti-her2/neu to image tumor surface antigens. This concept can potentially be expanded to a large number of targets and to in vivo applications.

Catheter-based in vivo imaging of enzyme activity and gene expression: feasibility study in mice

PURPOSE

To construct and evaluate an interventional catheter-based imaging system for intravital monitoring of molecularly sensitive near-infrared fluorescent probes and optical marker genes.

MATERIALS AND METHODS

An imaging device that was based on a miniaturized fiberoptic sensor (MIFS) was built in which images created with a 2.7-F fiberoptic catheter were relayed through a dichroic mirror, through a bandpass filter, and on two independent cameras. This system permitted simultaneous recording of white-light and fluorescent images. Spatial resolution, spectral transmissions, and sensitivity were determined in vitro. In vivo testing was performed in nude mice bearing intraperitoneal tumors that express green fluorescent protein and in a mouse model of ovarian carcinoma with enzyme-activatable near-infrared probes sensitive to tumoral protease activity. Signal intensity on images of tumors and that on images of normal tissue were measured and compared with t test.

RESULTS

The catheter, which was advanced through an 18-gauge sheath, showed resolution of 7 line pairs per millimeter and detection limit for fluorochrome Cy5.5 of 1-10 pmol. Detection of endogenous green fluorescent protein gene expression was feasible in tumor nodules smaller than 1 mm in diameter (mean tumor signal intensity, 153.26 +/- 26.45 [SD], compared with that of adjacent nontumoral tissue of 36.73 +/- 11.69; P <.008). Similarly, activation of the near-infrared probe by tumoral proteases could be detected in peritoneal tumor seeds of ovarian cancer model with mean tumor signal intensity of 246.33 +/- 7.77 compared with that of adjacent nontumoral tissue of 41.56 +/- 18.64 (P <.001). Mean contrast-to-noise ratio in the near-infrared channel exceeded white-light contrast-to-noise ratio by a factor of 6.7 (P <.02).

CONCLUSION

With this system, in vivo MIFS imaging of gene expression, enzyme activity, and potentially other molecular events is feasible, through direct interventional access to several organs and body cavities and potentially through transvascular approaches.

Influence of spectacle-related changes in retinal image size on contrast sensitivity function after laser in situ keratomileusis

PURPOSE

To evaluate changes in contrast sensitivity after laser in situ keratomileusis (LASIK) for the correction of myopia using a monitor-based method and considering the preoperative minification effect of high-diopter spectacles.

SETTING

Department of Ophthalmology, University of Vienna Medical School, Vienna, Austria.

METHODS

Fifteen eyes of 11 patients had LASIK to correct myopia. The best corrected visual acuity (BCVA) and contrast sensitivity function (CSF) were measured preoperatively and 1, 3, and 6 months postoperatively using the AcuityMax (Science 2020) computer program. The error in contrast sensitivity measurement due to different angular sizes of the test figures deriving from the spectacle refractions before and after LASIK were considered.

RESULTS

Preoperatively, and at 1, 3, and 6 months, the mean Snellen BCVA was 0.93 +/- 0.19 (SD), 0.80 +/- 0.26, 0.85 +/- 0.21, and 0.84 +/- 0.27, respectively. The best mean CS (measured at 1.1 logMAR) was 1.17 +/- 0.05, 1.12 +/- 0.07, 1.13 +/- 0.08, and 1.18 +/- 0.04, respectively. The strongest CS changes were observed at 0.7 logMAR (6 cycles per degree), where CS was 1.10 +/- 0.07 preoperatively and 1.06 +/- 0.09, 1.07 +/- 0.12, and 1.14 +/- 0.07, at 1 month, 3 months, and 6 months, respectively. With correction for the spectacle effect, the preoperative CS was approximately 3% higher and CS at 3 months for intermediate optotype sizes was significantly inferior to preoperatively.

CONCLUSIONS

With correction of different retinal image sizes before and after LASIK (due to different spectacle refraction), the CS was significantly below the preoperative values at 1 and 3 months and approached the preoperative values at 6 months. The proposed method is potentially capable of quality monitoring and method comparisons after photorefractive surgery.

Outcome after treatment of ametropia with implantable contact lenses

OBJECTIVE

To evaluate long-term results after insertion of implantable contact lenses (ICLs) in phakic eyes.

DESIGN

Prospective, noncomparative, interventional case series.

PARTICIPANTS

Seventy-five phakic eyes (65 myopic, 10 hyperopic eyes) of 45 patients aged 21.7 to 60.6 years were included.

INTERVENTION

STAAR Collamer Implantable Contact Lenses (STAAR Surgical Inc., Nidau, Switzerland) were implanted for correction of high myopia and hyperopia.

MAIN OUTCOME MEASURES

Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and intraocular pressure (IOP) were determined. Presence of lens opacification and the distance between the ICL and the crystalline lens were assessed by slit-lamp examination before surgery and at 1, 3, 6 months, and yearly after lens implantation.

RESULTS

Preoperative mean spherical equivalent was -16.23+/-5.29 diopters (D) for myopic eyes and +7.88 +/-1.46 D for hyperopic eyes. After ICL implantation, mean residual refractive error was -1.77+/-2.17 D in myopic patients and +0.44+/-0.69 D in hyperopic patients. Preoperative mean UCVA was Snellen 0.03+/-0.03 for myopic patients and Snellen 0.12+/-0.16 for hyperopic patients. Preoperative mean BCVA was Snellen 0.49+/-0.23 for myopic patients and Snellen 0.82+/-0.23 for hyperopic patients. After ICL implantation, mean UCVA up to the end of individual observation time was Snellen 0.36+/-0.36 for myopic patients and Snellen 0.58+/-0.28 for hyperopic patients. Mean BCVA was Snellen 0.73+/-0.26 for myopic and Snellen 0.80+/-0.24 for hyperopic patients. Mean preoperative IOP was 14.2+/-2.7 mmHg, and mean postoperative IOP was 13.46+/-2.1 mmHg over all follow-up investigations. The main complication was the development of subcapsular anterior opacifications of the crystalline lens in 25 eyes (33.3%), 2 of which showed direct contact to the ICL. Eleven eyes (14.7%) were stable in opacification and 14 eyes (18.7%) had progressive opacifications. The median time to opacification was 27.1 months. In 8 patients (10.7%), the subjective visual impairment mandated cataract surgery.

CONCLUSIONS

The most significant long-term complication after ICL implantation is the formation of opacifications of the crystalline lens with the risk of the necessity of subsequent cataract surgery (10.7%). Old age, female gender, and contralateral opacification are independent significant risk factors for early formation of opacifications in this patient group.

Impact of Ambient Light and Window Settings on the Detectability of Catheters on Soft-Copy Display of Chest Radiographs at Bedside

OBJECTIVE

The aim of this study was to evaluate how ambient light and interactive adjustment of density and contrast affect the detection of catheter fragments when interpreting bedside chest radiographs on soft-copy displays.

MATERIALS AND METHODS

A total of 131 catheter fragments were superimposed over 10 bedside chest radiographs obtained with storage phosphor technology. Images were displayed on a clinical intensive care unit viewing station (color cathode-ray tube monitor, 21 inch [53 cm], 1280 x 1024 matrix) and were independently evaluated by five radiologists. The number of catheter fragments per image varied between 12 and 14, with an approximately equal distribution in high- and low-absorption areas. Detectability of catheter fragments was assessed under subdued and bright ambient light conditions with and without interactive adjustment of window width and level.

RESULTS

Under subdued light, the detection rate of catheter fragments was significantly higher than under bright light (51.8% vs 56.6%, p < 0.05). Interactive window setting adjustment significantly increased the detection rate from 52.5% to 60.8% (p < 0.05) under subdued light and from 47.9% to 55.6% (p < 0.05) under bright light. With adjustment of window settings, the difference between the detection rates under subdued light (60.8%) and under bright light (55.6%) did not reach statistical significance.

CONCLUSION

Detection of catheters on soft-copy display is significantly decreased by bright ambient light, an effect that can be largely compensated for by means of interactive adjustment of window settings.

Miniaturized Multichannel Near Infrared Endoscope for Mouse Imaging

We describe the design and construction of a miniaturized multichannel near infrared (NIR) endoscopic imaging system developed for high-resolution imaging of mice. The device allows for simultaneous real-time video images in white light and two independent NIR channels. Testing demonstrated independent acquisition of nanomolar concentrations of fluorochromes Cy5.5 and Cy7. Cross-talk between the NIR channels, partially a result of broad tails in the spectra of commonly used organic fluorochromes, was assessed, modeled for the linear range of the concentration/signal intensity function, and compensated. The calculated compensation was 5.5% and 22% of the total signal intensity in the two channels NIR700 and NIR780, respectively, at equal concentrations of the two fluorochromes. Using a mouse model of colonic adenomatosis, we show that both perfusion and protease activity can be detected simultaneously, independently, and repeatedly in live mice. The developed device should be useful for in vivo imaging of diverse molecular targets.

Four-channel multidetector CT in facial fractures: do we need 2 x 0.5 mm collimation?

OBJECTIVE

Our aim was to optimize acquisition protocols and multiplanar reformation algorithms for the evaluation of facial fractures using multidetector CT (MDCT) and to determine whether 2 x 0.5 mm collimation is necessary.

MATERIALS AND METHODS

A cadaveric head with artificial blunt facial trauma was examined using a four-channel MDCT scanner. The influence of acquisition parameters (collimation, 2 x 0.5 mm, 4 x 1 mm, 4 x 2.5 mm; tube current, 120 mAs, 90 mAs, 60 mAs), image reconstruction algorithms (standard vs ultra-high-resolution modes; reconstructed slice thicknesses, 0.5 mm, 1 mm, 3 mm; increment, 0.3 mm, 0.6 mm, 1.5 mm), and reformation algorithms (slice thicknesses, 0.5 mm, 1 mm, 3 mm; overlap, 0.5 mm, 1 mm, 3 mm) on detectability of facial fractures in multiplanar reformations with MDCT was analyzed.

RESULTS

Fracture detection was significantly higher with thin multiplanar reformations (0.5 and 0.5 mm, 1 and 0.5 mm, and 1 and 1 mm) (p < or = 0.014) acquired with 2 x 0.5 mm collimation (p < or = 0.046) in ultra-high-resolution mode (p < 0.0005) with 120 mAs (p < or = 0.025). Interobserver variability showed very good agreement (kappa > or = 0.942). Non-ultra-high-resolution mode, lower milliampere-seconds, and thick multiplanar reformations (3 and 0.5 mm, 3 and 1 mm, and 3 and 0.5 mm) showed significantly decreased fracture detectability.

CONCLUSION

Although thin multiplanar reformations obtained from thin collimation (2 x 0.5 mm) are statistically superior for the detection of subtle fractures, 4 x 1 mm collimation is sufficient for routine diagnostic evaluation. Ultra-high-resolution mode with 120 mAs is mandatory for detection of clinically relevant fractures.

Feasibility study of NeoMend, a percutaneous arterial closure device that uses a nonthrombogenic bioadhesive

OBJECTIVE

The aim of this prospective single-center phase I feasibility study was to investigate the safety and efficacy of a novel vascular sealing device, the NeoMend Arterial Closure Device, that uses a bioadhesive after percutaneous endovascular procedures.

SUBJECTS AND METHODS

In 26 consecutive patients, the sealing device was deployed at the femoral artery access site immediately after a catheterization procedure using a 6-French (1.91-mm) sheath. Patients were followed up at 24 hr with Doppler sonography of the treated femoral artery puncture site, and at 1 week and 1 month by a telephone interview.

RESULTS

Successful hemostasis was achieved with the NeoMend Arterial Closure Device in 21 (88%) of 24 patients. One major complication required surgery: formation of puncture site hematoma and pseudoaneurysm 3 days after the intervention after successful primary hemostasis. Two device failures required crossover to manual compression, which was done without further complications. The mean time to hemostasis was 7.0 +/- 4.5 min. Mean time to ambulation was 6.0 hr. At follow-up, the patients did not report any puncture-site-related complaints. Doppler sonography of the puncture sites revealed three insignificant hematomas of less than 20 mL and patent common femoral vessels without stenoses.

CONCLUSION

The NeoMend Arterial Closure Device appears to achieve rapid hemostasis with the potential of early ambulation after arterial punctures with a 6-French sheath. The device is an alternative in situations in which suture- or collagen-mediated devices show high complication rates.

Galactography: method of choice in pathologic nipple discharge?

Our objective was to assess the role of galactography in the diagnostic work-up of patients with pathological nipple discharge together with exfoliative cytology, and investigation of secretion colour. All galactographies performed in this center between 1993 and 1998 were evaluated retrospectively. In 134 cases, outcomes, defined as either a postoperative histology or a negative follow-up over 2 years after galactography, were available. In 96 of these cases, exfoliative cytology was performed, and in 65 cases the colour of the secretion was determined. Galactograms, cytological findings and colour of the secretions were compared with the outcomes. At galactography, the radiographic findings had the following individual sensitivities/specificities in detecting carcinomas: filling defect 55.6%/62.1%; ductectasia 22.2%/94%; and filling stop 5.6%/77.6%. Normal galactograms (n=33, 25%) had a sensitivity of 78% and a specificity of 93% in predicting absence of disease. Technically inadequate investigations occurred in 16 (12%) cases. Cytology showed 69.2%/66.8% for papillomatous borderline or malignant cells; 53.8%/75.3% for borderline or malignant cells; and 7.7%/100% for one case of malignant cells. For the assessment of pathological secretions, galactography is a sensitive but unspecific method for the detection of papillomas or carcinomas. Filling defects, ductectasia and ductal distortion carry the highest levels of suspicion for carcinoma. A normal galactogram is a specific yet moderately sensitive indicator of absence of localized disease. Exfoliative cytology shows low sensitivity but better specificity for carcinomas when borderline or malignant cells are found. In the present series, the colour of the secretions does not add significant information about underlying pathology.

[Electrical impedance scanning in the differentiation of suspicious breast lesions: comparison with mammography, ultrasound and histopathology]

PURPOSE

To assess the value of Electrical Impedance Scanning (EIS) in the differentiation of suspicious breast lesions in comparison to mammography (MG) and ultrasound (US).

METHODS

In 95 female patients (median 53.1 ys) 95 suspicious breast lesions (BI-RADS TM III - V) in MG or US underwent targeted EIS (TransScan TS 2000(R); TransScan Medical, Israel; Siemens Elema, Sweden). Histopathologic proof (vacuum-assisted biopsy or surgical biopsy) was obtained in all cases. MG, US and EIS were independently assessed by two radiologists in consensus. Chi-square tests as well as variance-analysis for ROC-statistics were performed.

RESULTS

Of 95 lesions, 44 were benign, 51 malignant. Sensitivity, specificity, positive and negative predictive values were, respectively for MG 95.3 %, 23.5 %, 51.3 % and 85.7 %, for US 86.5 %, 44.2 %, 57.1 % and 79.1 %, for EIS 77.3 %, 82.3 %, 79.1 % and 80.8 %. The ROC-analysis revealed a significant greater area under the curve for EIS than for MG and US. The sensitivity for EIS was higher in lesions < 10 mm (n = 26; 100 %) and in invasive cancers (n = 31; 80.6 %). The negative predictive value of EIS was higher in BI-RADS TM-IV-lesions (83.9 %) as well as in dense breast parenchyma on the mammogram (86.7 %).

CONCLUSION

EIS shows potential adjunctive value to MG and US in the differentiation of suspicious breast lesions.

Malignant biliary obstruction: treatment with ePTFE-FEP- covered endoprostheses initial technical and clinical experiences in a multicenter trial

PURPOSE

To determine and present the initial technical and clinical results of using an expanded polytetrafluoroethylene-fluorinated ethylene propylene (ePTFE-FEP)-covered biliary endoprosthesis to treat malignant biliary obstruction.

MATERIALS AND METHODS

This prospective nonrandomized study included 42 patients with malignant obstruction of the common bile duct, common hepatic duct, and hilar confluence. Unilateral (n = 38) or bilateral (n = 4) bile duct drainage was performed by using fully covered endoprostheses with anchoring fins. To avoid branch duct blockage, endoprostheses with drainage holes at the proximal end were available. Procedure- and device-related complications were recorded. Patient survival and stent patency rates were calculated with Kaplan-Meier survival analysis. Mean follow-up bilirubin and alkaline phosphatase levels were calculated, and differences in means were evaluated with a paired t test.

RESULTS

Successful deployment, correct positioning, and patency of the device were achieved in all patients. Procedure-related complications occurred in two (5%) patients. Thirty-day mortality rate was 20% (eight of 41 patients), and median survival time was 146 days. Laboratory values decreased significantly after the procedure (P <.001). Recurrent obstructive jaundice occurred in six (15%) patients. Primary patency rates at 3, 6, and 12 months were 90%, 76%, and 76%, respectively. Calculation of the composite end point of death or obstruction revealed a median patency duration of 138 days. No endoprosthesis migration was observed. Branch duct obstruction was observed in four (10%) patients. Postmortem examination of one stent revealed a widely patent endoprosthesis with intact covering.

CONCLUSION

Initial results of percutaneous treatment of malignant biliary obstructions with fully covered ePTFE-FEP endoprostheses suggest that they are safe and potentially clinically effective.

Predictors of long-term results after treatment of iliac artery obliteration by transluminal angioplasty and stent deployment

PURPOSE

To investigate initial and long-term success rate after percutaneous treatment of iliac artery occlusion with angioplasty and stent deployment. To investigate the influence of vascular comorbidity, lesion length, stent placement and lesion coverage as possible predictors of outcome.

METHODS

Between January 1994 and December 1999, 80 iliac recanalizations were performed on 78 patients, median age 61.1 +/- 11.5 (SD) years. All patients were followed up by clinical examinations, duplex ultrasound and intravenous digital subtraction angiography. Mean follow-up time was 2.0 +/- 1.53 (SD) years. Multivariate Cox regression analysis was used to determine the influence of cofactors on patency.

RESULTS

One, 2 and 4 years after recanalization, primary patency was 78.1%, 74.5% and 64.0%; secondary patency was 88.8%, 88.8% and 77.9%, respectively. Patients with shorter occlusions, complete lesion coverage and patent ipsilateral femoral arteries had significantly longer patency rates. Complications included inguinal hematoma (n=1), technical failure (n=3) aortic dissection (n=1), embolic occlusions (n=7), gluteal claudication (n=1) and genital necrosis after subsequent urethral surgery in one patient with contralateral occlusion and ipsilateral overstenting of the internal iliac artery with subsequent stenosis. Complications were of permanent clinical significance in seven of 78 (9%) of the patients. In 17 (22%) cases, percutaneous reintervention was performed with angioplasty in the stent (n=16) or deployment of a new stent (n=1).

CONCLUSION

Endoluminal stent placement has its place in an interdisciplinary therapeutic approach as a viable therapeutic alternative to major transabdominal bypass surgery and can be performed with comparable complication rates. Patients with short occlusions, patent femoral arteries, and stents covering the entire occlusion have significant longer patency.

Evaluation of perianal sepsis: comparison of anal endosonography and magnetic resonance imaging

The purpose of this study was to compare prospectively the diagnostic yield of anal endosonography (AES) and magnetic resonance imaging (MRI) in the assessment of perianal fistulae and abscesses. There were 39 patients (14 men, 25 women; mean age, 40 years) who underwent AES, performed with a 10-MHz rotating endoanal probe and MRI at 1.0 T (axial and coronal T2-weighted turbo spin-echo (TSE) and turbo-STIR sequences). Fistulae were classified as subcutaneous, intersphincteric, transsphincteric, high (i.e., high extrasphincteric or suprasphincteric), rectovaginal, and horseshoe and were compared with the surgical findings in all patients. Overall, 58 fistulae (subcutaneous, N = 7; intersphincteric, N = 9; transsphincteric, N = 16; high, N = 17; rectovaginal, N = 5; and horseshoe, N = 4) were detected at surgery. MRI showed a sensitivity of 84% and AES of 60% (P <.05). False-positive diagnoses were made in 6 patients (15%) with MRI and in 15 patients (26%) with AES, for a specificity of 68% and 21%, respectively (P <.05). Our findings show that MRI is superior to AES in the assessment of fistula-in-ano before major surgery. AES should be used only for orientation before minor procedures, such as incision or drainage of subcutaneous fistulae.

Transrectal sonography of anal sphincter infiltration in lower rectal carcinoma

OBJECTIVE

The purpose of the study was to assess the accuracy of transrectal sonography in determining invasion by lower rectal cancer into the anal canal.

SUBJECTS AND METHODS

Thirty-eight patients (14 women, 24 men; mean age, 65 years) with lower rectal cancer underwent transrectal sonography before surgery. Both depth of infiltration and tumor invasion into the anal canal were assessed, and results were compared with histopathology of the resected specimens.

RESULTS

Infiltration into the anal canal was found histopathologically in 12 (32%) of 38 patients. Transrectal sonography revealed a true-positive diagnosis in 11 of these 12 patients. A false-positive diagnosis of anal canal infiltration was made in two patients for a sensitivity of 91%, a specificity of 85%, and an accuracy of 92%. In the 11 patients diagnosed correctly on transrectal sonography, the depth of tumor infiltration into the anal canal corresponded with histopathology.

CONCLUSION

This study shows that transrectal sonography is an accurate method for assessment of anal canal infiltration in lower rectal cancer.

Ultrasound therapy for calcific tendinitis of the shoulder

BACKGROUND AND METHODS

Although ultrasound therapy is used to treat calcific tendinitis of the shoulder, its efficacy has not been rigorously evaluated. We conducted a randomized, double-blind comparison of ultrasonography and sham insonation in patients with symptomatic calcific tendinitis verified by radiography. Patients were assigned to receive 24 15-minute sessions of either pulsed ultrasound (frequency, 0.89 MHz; intensity, 2.5 W per square centimeter; pulsed mode, 1:4) or an indistinguishable sham treatment to the area over the calcification. The first 15 treatments were given daily (five times per week), and the remainder were given three times a week for three weeks. Randomization was conducted according to shoulders rather than patients, so a patient with bilateral tendinitis might receive either or both therapies.

RESULTS

We enrolled 63 consecutive patients (70 shoulders). Fifty-four patients (61 shoulders) completed the study. There were 32 shoulders in the ultrasound-treatment group and 29 in the sham-treatment group. After six weeks of treatment, calcium deposits had resolved in six shoulders (19 percent) in the ultrasound-treatment group and decreased by at least 50 percent in nine shoulders (28 percent), as compared with respective values of zero and three (10 percent) in the sham-treatment group (P=0.003). At the nine-month follow-up visit, calcium deposits had resolved in 13 shoulders (42 percent) in the ultrasound-treatment group and improved in 7 shoulders (23 percent), as compared with respective values of 2 (8 percent) and 3 (12 percent) in the sham-treatment group (P=0.002). At the end of treatment, patients who had received ultrasound treatment had greater decreases in pain and greater improvements in the quality of life than those who had received sham treatment; at nine months, the differences between the groups were no longer significant.

CONCLUSIONS

In patients with symptomatic calcific tendinitis of the shoulder, ultrasound treatment helps resolve calcifications and is associated with short-term clinical improvement.