A Real-Time Blood Flow Measurement Device for Patients with Peripheral Artery Disease.

PURPOSE: To evaluate the feasibility of a new optical device that measures peripheral blood flow as a diagnostic and monitoring tool for patients with peripheral artery disease (PAD). MATERIALS AND METHODS: In this prospective study, 167 limbs of 90 patients (mean age, 76 y; 53% men) with suspected PAD were evaluated with the FlowMet device, which uses a new type of dynamic light-scattering technology to assess blood flow in real time. Measurements of magnitude and phasicity of blood flow were combined into a single-value flow-waveform score and compared vs ankle-brachial index (ABI), toe-brachial index (TBI), and clinical presentation of patients per Rutherford category (RC). Receiver operating characteristic curves were constructed to predict RC. Area under the curve (AUC), sensitivity, and specificity were compared among flow-waveform score, ABI, and TBI. RESULTS: Qualitatively, the FlowMet waveforms were analogous to Doppler velocity measurements, and degradation of waveform phasicity and amplitude were observed with increasing PAD severity. Quantitatively, the flow, waveform, and composite flow-waveform scores decreased significantly with decreasing TBI. In predicting RC ≥ 4, the flow-waveform score (AUC = 0.83) showed a linear decrease with worsening patient symptoms and power comparable to that of TBI (AUC = 0.82) and better than that of ABI (AUC = 0.71). Optimal sensitivity and specificity pairs were found to be 56%/83%, 72%/81%, and 89%/74% for ABI, TBI, and flow-waveform score, respectively. CONCLUSIONS: The technology tested in this pilot study showed a high predictive value for diagnosis of critical limb ischemia. The device showed promise as a diagnostic tool capable of providing clinical feedback in real time.

Differential knee joint loading patterns during gait for individuals with tibiofemoral and patellofemoral articular cartilage defects in the knee.

OBJECTIVE: To determine compartment-specific loading patterns during gait, quantified as joint reaction forces (JRF), of individuals with knee articular cartilage defects (ACD) compared to healthy controls (HC). METHODS: Individuals with ACDs and HC participated. Individuals with ACDs were divided into groups according to ACD location: PF (only a patellofemoral ACD), TF (only a tibiofemoral ACD), and MIX (both PF and TF ACDs). Participants underwent three-dimensional gait analysis at self-selected speed. TF joint reaction force (TF-JRF) was calculated using inverse dynamics. PF joint reaction force (PF-JRF) was derived from estimated quadriceps force (FQUAD) and knee flexion angle. Primary variables of interest were the PF- and TF-JRF peaks (body weight [×BW]). Related secondary variables (gait speed, quadriceps strength, knee function, activity level) were evaluated as covariates. RESULTS: First peak PF-JRF and TF-JRF were similar in the TF and MIX groups (0.75-1.0 ×BW, P = 0.6-0.9). Both peaks were also similar in the PF and HC groups (1.1-1.3 ×BW, P = 0.7-0.8), and higher than the TF and MIX groups (P = 0.004-0.02). For the second peak PF-JRF, only the HC group was higher than the TF group (P = 0.02). The PF group walked at a similar speed as the HC group; both groups walked faster than the TF and MIX groups (P < 0.001). With gait speed and quadriceps strength as covariates, no differences were observed in JRF peaks. CONCLUSIONS: The results suggest the presence of a TF ACD (TF and MIX groups), but not a PF ACD (PF group), may affect joint loading patterns during walking. Walking slower may be a protective gait modification to reduce load.

Meniscus treatment and age associated with narrower radiographic joint space width 2-3 years after ACL reconstruction: data from the MOON onsite cohort.

OBJECTIVE: To identify risk factors for radiographic signs of post-traumatic osteoarthritis (OA) 2-3 years after anterior cruciate ligament (ACL) reconstruction through multivariable analysis of minimum joint space width (mJSW) differences in a specially designed nested cohort. METHODS: A nested cohort within the Multicenter Orthopaedic Outcomes Network (MOON) cohort included 262 patients (148 females, average age 20) injured in sport who underwent ACL reconstruction in a previously uninjured knee, were 35 or younger, and did not have ACL revision or contralateral knee surgery. mJSW on semi-flexed radiographs was measured in the medial compartment using a validated computerized method. A multivariable generalized linear model was constructed to assess mJSW difference between the ACL reconstructed and contralateral control knees while adjusting for potential confounding factors. RESULTS: Unexpectedly, we found the mean mJSW was 0.35 mm wider in ACL reconstructed than in control knees (5.06 mm (95% CI 4.96-5.15 mm) vs 4.71 mm (95% CI 4.62-4.80 mm), P < 0.001). However, ACL reconstructed knees with meniscectomy had narrower mJSW compared to contralateral normal knees by 0.64 mm (95% C.I. 0.38-0.90 mm) (P < 0.001). Age (P < 0.001) and meniscus repair (P = 0.001) were also significantly associated with mJSW difference. CONCLUSION: Semi-flexed radiographs can detect differences in mJSW between ACL reconstructed and contralateral normal knees 2-3 years following ACL reconstruction, and the unexpected wider mJSW in ACL reconstructed knees may represent the earliest manifestation of post-traumatic osteoarthritis and warrants further study.

Tibiofemoral subchondral surface ratio (SSR) is a predictor of osteoarthritis symptoms and radiographic progression: data from the Osteoarthritis Initiative (OAI).

OBJECTIVE: Symptomatic knee osteoarthritis (OA) is poorly correlated with radiographic severity, but subchondral bone measures may be useful for risk assessment as bone shape is grossly unaffected at early radiographic stages. We sought to determine whether compartment-specific size mismatch in the naturally asymmetric tibiofemoral joint, measured as tibiofemoral subchondral surface ratio (SSR): (1) predicts incident symptoms, (2) predicts incident or progressive OA, (3) is reproducible and time invariant. DESIGN: OA Initiative participants with baseline MRIs and up to 48-month follow-up (n = 1,338) were analyzed. Logistic regression was used to determine the association between SSR and incident symptoms, incident OA, and progression of OA after adjusting for demographic, radiologic, injury-related, and lifestyle-related factors. Reproducibility was assessed as % coefficient of variation (CV) on repeat MRI studies at baseline and 24 months. RESULTS: Increased medial SSR is protective against incident symptoms at 48 months (per 0.1 increase: OR 0.48 CI 0.30, 0.75; P = 0.001). Increased lateral SSR values are protective against lateral OA incidence (OR 0.23 CI 0.06, 0.77; P = 0.016) or progression (OR 0.66 CI 0.43, 0.99; P = 0.049) at 24 months. Both medial and lateral SSR are stable over time (medial: mean change 0.001 SD 0.016; lateral: mean change 0.000 SD 0.017) and are highly reproducible (3.0% CV medial SSR; 2.7% CV lateral SSR). CONCLUSIONS: A larger medial SSR is protective against developing OA-related symptoms. A larger lateral SSR is protective against lateral OA incidence or progression. Finally, lateral and medial SSR are stable over time and are highly reproducible across MRI studies.

Evidence for gravitational lensing of the cosmic microwave background polarization from cross-correlation with the cosmic infrared background.

We reconstruct the gravitational lensing convergence signal from cosmic microwave background (CMB) polarization data taken by the Polarbear experiment and cross-correlate it with cosmic infrared background maps from the Herschel satellite. From the cross spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0σ and indication of the presence of a lensing B-mode signal at a significance of 2.3σ. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics.

Measurement of the cosmic microwave background polarization lensing power spectrum with the POLARBEAR experiment.

Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.

Failures, re-operations, and complications after autologous chondrocyte implantation--a systematic review.

OBJECTIVE: To determine and compare failure, re-operation, and complication rates of all generations and techniques of autologous chondrocyte implantation (ACI). METHODS: A systematic review of multiple medical databases was performed according to PRISMA guidelines. Levels I-IV evidence were included. Generations of ACI and complications after ACI were explicitly defined. All subject and defect demographic data were analyzed. Modified Coleman Methodology Scores (MCMSs) were calculated for all studies. RESULTS: 82 studies were identified for inclusion (5276 subjects were analyzed; 6080 defects). Ninety percent of the studies in this review were rated poor according to the MCMS. There were 305 failures overall (5.8% subjects; mean time to failure 22 months). Failure rate was highest with periosteal ACI (PACI). Failure rates after PACI, collagen-membrane cover ACI (CACI), second generation, and all-arthroscopic, second-generation ACI were 7.7%, 1.5%, 3.3%, and 0.83%, respectively. The failure rate of arthrotomy-based ACI was 6.1% vs 0.83% for all-arthroscopic ACI. Overall rate of re-operation was 33%. Re-operation rate after PACI, CACI, and second-generation ACI was 36%, 40%, and 18%, respectively. However, upon exclusion of planned second-look arthroscopy, re-operation rate was highest after PACI. Unplanned re-operation rates after PACI, CACI, second-generation, and all-arthroscopic second-generation ACI were 27%, 5%, 5%, and 1.4%, respectively. Low numbers of patients undergoing third-generation ACI precluded comparative analysis of this group. CONCLUSIONS: Failure rate after all ACI generations is low (1.5-7.7%). Failure rate is highest with PACI, and lower with CACI and second-generation techniques. One out of three ACI patients underwent a re-operation. Unplanned re-operations are seen most often following PACI. Hypertrophy and delamination is most commonly seen after PACI. Arthrofibrosis is most commonly seen after arthrotomy-based ACI. Use of a collagen-membrane cover, second-generation techniques, and all-arthroscopic, second-generation approaches have reduced the failure, complication, and re-operation rate after ACI.

Direct delayed human adenoviral BMP-2 or BMP-6 gene therapy for bone and cartilage regeneration in a pony osteochondral model.

OBJECTIVE: To evaluate healing of surgically created large osteochondral defects in a weight-bearing femoral condyle in response to delayed percutaneous direct injection of adenoviral (Ad) vectors containing coding regions for either human bone morphogenetic proteins 2 (BMP-2) or -6. METHODS: Four 13mm diameter and 7mm depth circular osteochondral defects were drilled, 1/femoral condyle (n=20 defects in five ponies). At 2 weeks, Ad-BMP-2, Ad-BMP-6, Ad-green fluorescent protein (GFP), or saline was percutaneously injected into the central drill hole of the defect. Quantitative magnetic resonance imaging (qMRI) and computed tomography (CT) were serially performed at 12, 24, and 52 weeks. At 12 (one pony) or 52 weeks, histomorphometry and microtomographic analyses were performed to assess subchondral bone and cartilage repair tissue quality. RESULTS: Direct delivery of Ad-BMP-6 demonstrated delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and histologic evidence of greater Glycosaminoglycan (GAG) content in repair tissue at 12 weeks, while Ad-BMP-2 had greater non-mineral cartilage at the surface at 52 weeks (p<0.04). Ad-BMP-2 demonstrated greater CT subchondral bone mineral density (BMD) by 12 weeks and both Ad-BMP-2 and -6 had greater subchondral BMD at 52 weeks (p<0.05). Despite earlier (Ad-BMP-6) and more persistent (Ad-BMP-2) chondral tissue and greater subchondral bone density (Ad-BMP-2 and -6), the tissue within the large weight-bearing defects at 52 weeks was suboptimal in all groups due to poor quality repair cartilage, central fibrocartilage retention, and central bone cavitation. Delivery of either BMP by this method had greater frequency of subchondral bone cystic formation (p<0.05). CONCLUSIONS: Delivery of Ad-BMP-2 or Ad-BMP-6 via direct injection supported cartilage and subchondral bone regeneration but was insufficient to provide long-term quality osteochondral repair.

32nd International Austrian Winter Symposium : Zell am See, the Netherlands. 20-23 January 2016.

TABLE OF CONTENTS: A1 68Ga-PSMA PET/CT in staging and restaging of Prostate Cancer Patients: comparative study with 18F-Choline PET/CTW Langsteger, A Rezaee, W Loidl, HS Geinitz, F Fitz, M Steinmair, G Broinger, L Pallwien-Prettner, M BeheshtiA2 F18 Choline PET - CT: an accurate diagnostic tool for the detection of parathyroid adenoma?L Imamovic, M Beheshti, G Rendl, D Hackl, O Tsybrovsky, M Steinmair, K Emmanuel, F Moinfar, C Pirich, W LangstegerA3 [18F]Fluoro-DOPA-PET/CT in the primary diagnosis of medullary thyroid carcinomaA Bytyqi, G Karanikas, M Mayerhöfer, O Koperek, B Niederle, M HartenbachA4 Variations of clinical PET/MR operations: An international survey on the clinical utilization of PET/MRIT Beyer, K Herrmann, J CzerninA5 Standard Dixon-based attenuation correction in combined PET/MRI: Reproducibility and the possibility of Lean body mass estimationI Rausch, P Rust, MD DiFranco, M Lassen, A Stadlbauer, ME Mayerhöfer, M Hartenbach, M Hacker, T BeyerA6 High resolution digital FDG PET/MRI imaging for assessment of ACL graft viabilityK Binzel, R Magnussen, W Wei, MU Knopp, DC Flanigan, C Kaeding, MV KnoppA7 Using pre-existing hematotoxicity as predictor for severe side effects and number of treatment cycles of Xofigo therapyA Leisser, M Nejabat, M Hartenbach, G Kramer, M Krainer, M Hacker, A HaugA8 QDOSE - comprehensive software solution for internal dose assessmentWencke Lehnert, Karl Schmidt, Sharok Kimiaei, Marcus Bronzel, Andreas KlugeA9 Clinical impact of Time-of-Flight on next-generation digital PET imaging of Yttrium-90 radioactivity following liver radioembolizationCL Wright, K Binzel, J Zhang, Evan Wuthrick, Piotr Maniawski, MV KnoppA10 Snakes in patients! Lessons learned from programming active contours for automated organ segmentationM Blaickner, E Rados, A Huber, M Dulovits, H Kulkarni, S Wiessalla, C Schuchardt, RP Baum, B Knäusl, D GeorgA11 Influence of a genetic polymorphism on brain uptake of the dual ABCB1/ABCG2 substrate [11C]tariquidarM Bauer, B Wulkersdorfer, W Wadsak, C Philippe, H Haslacher, M Zeitlinger, O LangerA12 Outcome prediction of temporal lobe epilepsy surgery from P-glycoprotein activity. Pooled analysis of (R)-[11C]-verapamil PET data from two European centresM Bauer, M Feldmann, R Karch, W Wadsak, M Zeitlinger, MJ Koepp, M-C Asselin, E Pataraia, O LangerA13 In-vitro and in-vivo characterization of [18F]FE@SNAP and derivatives for the visualization of the melanin concentrating hormone receptor 1M Zeilinger, C Philippe, M Dumanic, F Pichler, J Pilz, M Hacker, W Wadsak, M MitterhauserA14 Reducing time in quality control leads to higher specific radioactivity of short-lived radiotracersL Nics, B Steiner, M Hacker, M Mitterhauser, W WadsakA15 In vitro 11C-erlotinib binding experiments in cancer cell lines with epidermal growth factor receptor mutationsA Traxl, Thomas Wanek, Kushtrim Kryeziu, Severin Mairinger, Johann Stanek, Walter Berger, Claudia Kuntner, Oliver LangerA16 7-[11C]methyl-6-bromopurine, a PET tracer to measure brain Mrp1 function: radiosynthesis and first PET evaluation in miceS Mairinger, T Wanek, A Traxl, M Krohn, J Stanek, T Filip, M Sauberer, C Kuntner, J Pahnke, O LangerA17 18F labeled azidoglucose derivatives as "click" agents for pretargeted PET imagingD Svatunek, C Denk, M Wilkovitsch, T Wanek, T Filip, C Kuntner-Hannes, J Fröhlich, H MikulaA18 Bioorthogonal tools for PET imaging: development of radiolabeled 1,2,4,5-TetrazinesC Denk, D Svatunek, T Wanek, S Mairinger, J Stanek, T Filip, J Fröhlich, H Mikula, C Kuntner-HannesA19 Preclinical evaluation of [18F]FE@SUPPY- a new PET-tracer for oncologyT Balber, J Singer, J Fazekas, C Rami-Mark, N Berroterán-Infante, E Jensen-Jarolim, W Wadsak, M Hacker, H Viernstein, M MitterhauserA20 Investigation of Small [18F]-Fluoroalkylazides for Rapid Radiolabeling and In Vivo Click ChemistryC Denk, D Svatunek, B Sohr, H Mikula, J Fröhlich, T Wanek, C Kuntner-Hannes, T FilipA21 Microfluidic 68Ga-radiolabeling of PSMA-HBED-CC using a flow-through reactorS Pfaff, C Philippe, M Mitterhauser, M Hartenbach, M Hacker, W WadsakA22 Influence of 24-nor-ursodeoxycholic acid on hepatic disposition of [18F]ciprofloxacin measured with positron emission tomographyT Wanek, E Halilbasic, M Visentin, S Mairinger, B Stieger, C Kuntner, M Trauner, O LangerA23 Automated 18F-flumazenil production using chemically resistant disposable cassettesP Lam, M Aistleitner, R Eichinger, C ArtnerA24 Similarities and differences in the synthesis and quality control of 177Lu-DOTA-TATE, 177Lu -HA-DOTA-TATE and 177Lu-DOTA-PSMA (PSMA-617)H Eidherr, C Vraka, A Haug, M Mitterhauser, L Nics, M Hartenbach, M Hacker, W WadsakA25 68Ga- and 177Lu-labelling of PSMA-617H Kvaternik, R Müller, D Hausberger, C Zink, RM AignerA26 Radiolabelling of liposomes with 67Ga and biodistribution studies after administration by an aerosol inhalation systemU Cossío, M Asensio, A Montes, S Akhtar, Y te Welscher, R van Nostrum, V Gómez-Vallejo, J LlopA27 Fully automated quantification of DaTscan SPECT: Integration of age and gender differencesF VandeVyver, T Barclay, N Lippens, M TrochA28 Lesion-to-background ratio in co-registered 18F-FET PET/MR imaging - is it a valuable tool to differentiate between low grade and high grade brain tumor?L Hehenwarter, B Egger, J Holzmannhofer, M Rodrigues-Radischat, C PirichA29 [11C]-methionine PET in gliomas - a retrospective data analysis of 166 patientsN Pötsch, I Rausch, D Wilhelm, M Weber, J Furtner, G Karanikas, A Wöhrer, M Mitterhauser, M Hacker, T Traub-WeidingerA30 18F-Fluorocholine versus 18F-Fluorodeoxyglucose for PET/CT imaging in patients with relapsed or progressive multiple myeloma: a pilot studyT Cassou-Mounat, S Balogova, V Nataf, M Calzada, V Huchet, K Kerrou, J-Y Devaux, M Mohty, L Garderet, J-N TalbotA31 Prognostic benefit of additional SPECT/CT in sentinel lymph node mapping of breast cancer patientsS Stanzel, G Pregartner, T Schwarz, V Bjelic-Radisic, B Liegl-Atzwanger, R AignerA32 Evaluation of diagnostic value of TOF-18F-FDG PET/CT in patients with suspected pancreatic cancerS Stanzel, F Quehenberger, RM AignerA33 New quantification method for diagnosis of primary hyperpatahyroidism lesions and differential diagnosis vs thyropid nodular disease in dynamic scintigraphyA Koljevic Markovic, Milica Jankovic, V Miler Jerkovic, M Paskas, G Pupic, R Dzodic, D PopovicA34 A rare case of diffuse pancreatic involvement in patient with merkel cell carcinoma detected by 18F-FDGMC Fornito, D FamiliariA35 TSH-stimulated 18F-FDG PET/CT in the diagnosis of recurrent/metastatic radioiodine-negative differentiated thyroid carcinomas in patients with various thyroglobuline levelsP Koranda, H Polzerová, I Metelková, L Henzlová, R Formánek, E Buriánková, M KamínekA36 Breast Dose from lactation following I131 treatmentWH Thomson, C LewisA37 A new concept for performing SeHCAT studies with the gamma cameraWH Thomson, J O'Brien, G James, A NotghiA38 Whole body F-18-FDG-PET and tuberculosis: sensitivity compared to x-ray-CTH Huber, I Stelzmüller, R Wunn, M Mandl, F Fellner, B Lamprecht, M GabrielA39 Emerging role 18F-FDG PET-CT in the diagnosis and follow-up of the infection in heartware ventricular assist system (HVAD)MC Fornito, G LeonardiA40 Validation of Poisson resampling softwareWH Thomson, J O'Brien, G JamesA41 Protection of PET nuclear medicine personnel: problems in satisfying dose limit requirementsJ Hudzietzová, J Sabol, M Fülöp.

Differences between arterial and mixed venous levels of plasma hydroperoxides following major thoracic and abdominal operations.

Fatty acid hydroperoxides in the plasma of 18 patients who were undergoing normal postoperative periods following major thoracic or abdominal operations were measured by using a sensitive assay based upon the activation of the cyclooxygenase activity of prostaglandin H synthase. Following major thoracic operations of nine patients, the mean difference between the arterial (0.49 +/- 0.13 microM, mean +/- S.E.M.) and mixed venous (-0.09 +/- 0.12 microM) level of hydroperoxide was 0.58 +/- 0.13 microM (p less than 0.01). In marked contrast to this result, major abdominal operations of nine patients led to a mean difference between the arterial (-0.19 +/- 0.16 microM) and mixed venous (0.46 +/- 0.08 microM) hydroperoxide levels of -0.65 +/- 0.17 microM (p less than 0.01). Both pulmonary and intraabdominal tissues appear capable of generating significant amounts of fatty acid hydroperoxide in response to standard surgical procedures. The A-MV differences suggest that the blood-borne hydroperoxides were rapidly cleared from the circulation by tissue capillary beds.

Detection of experimental arterial defects by portable and serial biplanar operative arteriography.

The accuracy of arteriography in detecting vascular defects similar to those encountered during vascular surgery was evaluated experimentally. Intimal flaps, thrombi, and strictures were created in dog aortas and studied under circumstances resembling operating room conditions by single-view portable and serial biplanar contrast arteriography. The specificity of both types of arteriography was comparable and high for detecting vascular defects. The sensitivity for diagnosing strictures was also comparable and high. However, both radiographic techniques were relatively insensitive in the detection of small intimal flaps and thrombi. In the detection of these two types of defects, serial biplanar arteriography was significantly more sensitive than portable arteriography. The degree of the superiority of serial bi-plane and the possible clinical insignificance of small defects indicates that portable arteriography in the operating room may still be an adequate methodology.

Ultrasonography of blood during stasis and coagulation.

A series of in vitro and animal experiments were performed to determine ultrasonic features of blood during stasis and coagulation. Liquid whole blood became echogenic within a few seconds to 3 minutes following the onset of stasis. This occurred in citrated human blood allowed to stand and in occluded segments of vena cava and aorta of dogs. Mechanical agitation of the blood in stasis caused a disappearance of echoes. This echogenicity occurred with gray-scale and real-time ultrasonography using 7.5-mHz transducers, but was not observed with 3.5-mHz transducer used in real-time scanning. Whole blood clot was echogenic both with 7.5- and 3.5-mHz scanning. Fibrin clot was sonolucent. Echogenicity with stasis did not occur with plasma, serum, or packed erythrocytes. The development of echogenicity required the presence of fibrinogen or its products plus erythrocytes. The echogenicity of blood during stasis detectable by high-frequency ultrasonography probably was related to physical layering of blood products. The disappearance of reflective echoes following agitation suggested that the layering could be readily disrupted.

Computerization of academic vascular surgery.

Academic surgical units have a combination of computer needs, including access to the surgical literature, storage and retrieval of patient registry data, laboratory, and research data, generation of reports; statistical analysis of data; and word processing. A system that fulfills these requirements was developed for an academic vascular surgical unit. The system integrates these functions in a multi-user environment and is accessed from menus on multiple terminals in laboratories and offices in three hospitals and in staff members' homes. Databases currently include more than 7000 references to published articles in vascular surgery, a vascular registry consisting of more than 7500 patients, patient data from three integrated noninvasive vascular laboratories, data generated from both clinical and basic research, and a log of resident, fellow, and faculty operative experience. Statistical analysis, using essentially all modern statistical methods including sophisticated log-rank, proportional hazards, and multivariant analyses, can be performed on all databases, either separately or in any combination, without the need to reenter data. An electronic mail and messaging system provides for paperless communication between surgeons, research personnel, and clerical staff.

Antibiotic binding to polytetrafluoroethylene via glucosaminoglycan-keratin luminal coating.

Vascular prosthetic graft infection is one of the most catastrophic problems complicating vascular surgery. The purpose of the present study was to determine the efficacy of binding an antibiotic to a vascular prosthesis via a glucosaminoglycan-keratin luminal coating (GKLC). Ten adult mongrel dogs had polytetrafluoroethylene (PTFE) grafts inserted into the right common carotid artery and PTFE grafts with GKLC bonded with cefoxitin inserted into the left common carotid artery. Before the neck incision was closed, an infusion of 1 X 10(8) Staphylococcus aureus was administered intravenously during a 15-minute period to each dog. Grafts were harvested at 10 different time periods (1, 2, 3, 5, 7, 10, 14, 18, 21, and 28 days). At the time of harvesting, cultures were taken of the lumen of each graft. Washout of antibiotic from the graft lumen was determined by measuring zones of inhibition of disks excised from the antibiotic grafts that were placed on S. aureus plates. Results demonstrated that only 1 of the 10 GKLC-cefoxitin grafts was infected compared with 10 of 10 regular PTFE grafts (p less than 0.003). Regression analysis showed antibiotic elution to occur in an exponential fashion (r = 0.9654) with no detectable antibiotic present after 10 days. GKLC with cefoxitin significantly protects the PTFE graft lumen from infection during bacteremia compared with regular PTFE. The role of antibiotic-bound grafts in relation to the use of intravenous antibiotics will need to be determined by further studies.

Prebypass operative arteriography.

Complete arteriographic delineation of lower extremity arterial anatomy is not always possible preoperatively. Nonvisualization of patent arterial segments may lead to amputation in lieu of arterial bypass grafting. During a 3-year period (1978 to 1981), 31 patients evaluated for lower extremity arterial bypass had incomplete preoperative arteriographic studies. Eighty-seven percent of these patients were in limb salvage categories. In order to obtain better arterial visualization, 33 operative arteriograms, preceding 32 operative procedures, were performed through the femoral (n = 14), popliteal (n = 17), posterior tibial (n = 1), and dorsal pedial (n = 1) arteries. All arteriograms were performed following arterial dissection and clamp occlusion of arterial inflow. The operative arteriogram was found to be beneficial in 91% of cases (29 of 32). In 66%, bypass was performed to vessels that were not visualized preoperatively. In 25%, bypasses were performed to vessels that were visualized preoperatively but intraoperative arteriograms showed better visualization of the vessels and distal runoff, thus allowing bypass to the optimal recipient artery. In three cases (9%), the intraoperative technique was not beneficial, as no additional arterial visualization was provided. Only one patient could not undergo bypass because of nonvisualization of recipient vessels. Overall, major amputation was avoided in 86% of patients (24 of 28) suffering from severe rest pain or gangrene during the period of study. Prebypass operative arteriography is a technique that clearly provides for increased limb salvage. Ninety-three percent of patients (14 of 15) otherwise facing immediate major amputation had their limbs salvaged through the use of this technique.

Hemodynamic evaluation of the aortoiliac system based on pharmacologic vasodilatation.

Selection of the appropriate vascular reconstructive procedure in patients with multisegment disease requires the differentiation of aortoiliac from femoropopliteal occlusive disease and the detection of subcritical stenoses in the aortoiliac segment. Triplane arteriography and common femoral intra-arterial papaverine injection (30 mg) were done in 43 lower extremities in patients who subsequently had arterial bypass. The percent diameter stenosis was measured on the arteriograms and common femoral intra-arterial pressure was continuously monitored before and after papaverine injection. A resting femoral/brachial pressure index (FBI) was obtained and the percent decrease in this index (% delta FBI) was calculated using the maximum decrease in FBI following injection. Regression analysis revealed a significant correlation between % delta FBI and percent aortoiliac stenosis (r = 0.5446, P less than 0.005). In relation to clinical course, receiver-operator characteristic curve analysis revealed a % delta FBI of greater than or equal to 0.15 to be optimal in the detection of hemodynamically significant aortoiliac stenoses. When compared to clinical course, this % delta FBI was 88% sensitive, 100% specific, and 95% accurate. However, when analyzed with arteriography as the standard (50% stenosis), the same % delta FBI was only 70% sensitive, 100% specific, and 86% accurate. All limbs with a % delta FBI of 0.15 or greater improved following aortoiliac revascularization; 21% of these limbs had a normal preoperative resting FBI. No patient with a % delta FBI lower than 0.15 had improvement following aortoiliac revascularization. All limbs that had infrainguinal bypass had normal FBIs and % delta FBIs before bypass. After operation 90% of these limbs improved. Overall, this technique correctly predicted the clinical course in 95% of the limbs tested.

Intraoperative ultrasonic imaging of the carotid artery during carotid endarterectomy.

Intraoperative real-time B-mode ultrasonography was used to evaluate the technical results of 155 carotid endarterectomies in 143 patients. Technical defects created as a result of the endarterectomy were detected in 43 of the 155 endarterectomies (27.7%) and included intimal flaps (73% of defects); strictures (18%); and arterial kinks, residual plaque, and intraluminal thrombi (9% collectively). Eleven of the 43 endarterectomy sites (7% of all endarterectomies) were reentered to correct a defect; none of these patients had neurologic deficits, which suggests that reentering an endarterectomy and correcting a defect does not, in and of itself, lead to a higher incidence of stroke. The incidence of stroke in patients with normal results of intraoperative ultrasonography was 3.8%, whereas the incidence of perioperative stroke in those patients with insignificant and thus uncorrected defects was 3.3%; this suggests that intraoperative ultrasonography is sufficiently sensitive to detect defects that, when left uncorrected, do not lead to a higher than usual incidence of stroke. Because intraoperative ultrasonography is safe and highly sensitive, we believe it is the method of choice for assessing the technical results of carotid endarterectomy.

Sequential femoral-tibial bypass for severe limb ischemia.

Sequential femoral-popliteal-tibial bypass has been recommended for surgical treatment of severe lower limb ischemia in patients with complex multisegmental arterial occlusion. To evaluate this alternative technique critically, sequential grafting was performed in 40 limbs with severe ischemia manifest by rest pain (20), nonhealing ulceration (eight), or gangrene (12). Measurement of segmental Doppler arterial pressure revealed a significant increase in ankle brachial index from 0.29 +/- 0.15 before operation to 0.93 +/- 0.12 after operation, confirming the hemodynamic improvement among these patients. In the early postoperative period occlusion of the distal graft segment was recognized in 12 patients by a characteristic reduction of the ankle/brachial index (0.50 +/- 0.14), while the low thigh pressures remained unchanged. Recurrent severe ischemia was prevented in most by persistent patency of the proximal graft segment. Overall, significant hemodynamic improvement was achieved in 29 of 38 limbs, a limb salvage rate (76%) comparable to that reported for femoral-distal bypass or femoral-popliteal bypass to an isolated popliteal segment. Early graft failure in this series resulted in major amputation in eight of 16 limbs, a significantly lower rate than for these other techniques. Sequential bypass grafting is a useful alternative method for limb salvage. The preservation of the proximal graft patency after distal segmental occlusion may be an important characteristic of this type of reconstruction.

Ankle pressure changes in distal bypass grafts during knee flexion.

Systolic ankle blood pressure was measured with the limb extended and then acutely flexed in four study groups. These included 11 normal individuals, 11 patients with below-knee autologous saphenous vein bypass grafts, 11 patients with polytetrafluoroethylene (PTFE) prosthetic below-knee bypass grafts, and 11 patients with femoropopliteal arterial occclusion who had not undergone bypass grafting. This study shows that normal limbs, limbs with saphenous vein bypass grafts, arteriosclerotic limbs, and those with PTFE bypass grafts all tolerate acute knee flexion without significant decrease in distal blood pressure.

The effect of carotid siphon stenosis on stroke rate, death, and relief of symptoms following elective carotid endarterectomy.

It has been suggested that carotid endarterectomy for carotid bifurcation disease may be contraindicated in the presence of carotid siphon lesions. This study was undertaken to assess any difference in stroke rate, mortality, or relief of symptoms in patients with and without such "tandem" lesions following elective carotid endarterectomy. Ninety-one bifurcation endarterectomies were performed in 79 patients. The patients were divided into two groups. Group I (44 patients, 47 endarterectomies) had carotid bifurcation stenosis only; group I (35 patients, 44 endarterectomies) had siphon stenosis plus bifurcation stenosis. All patients in both groups who were symptomatic before operation were relieved of their symptoms. In group I there were no intraoperative or perioperative strokes, four late strokes (8.7%), one operate death (2.1%), and no late deaths. Group II patients had two intraoperative strokes (4.5%), three perioperative strokes (6.8%), two late strokes (5.1%), four operative deaths (9.1%), and three late deaths (7.5%). Eighteen of the 35 patients in group II had a greater degree of carotid siphon stenosis than bifurcation stenosis. In this subgroup, there was one operative stroke (5.6%), only perioperative stroke (5.6%), one late stroke (5.9%), one postoperative death (5.6%), and one late death (5.6%). None of these differences were statistically significant. Relief of symptoms was the same in patients with and without tandem carotid lesions, and there was no significantly increased risk of stroke or death following bifurcation endarterectomy in patients with tandem carotid lesions.