National trends in Staphylococcus aureus infection rates: impact on economic burden and mortality over a 6-year period (1998-2003).

BACKGROUND: We evaluated historical trends in the Staphylococcus aureus infection rate, economic burden, and mortality in US hospitals from 1998 through 2003. METHODS: The Nationwide Inpatient Sample was used to assess trends over time of S. aureus infection during 1998-2003. Historical trends were determined for 5 strata of hospital stays, including all inpatient stays, surgical procedure stays, invasive cardiovascular surgical stays, invasive orthopedic surgical stays, and invasive neurosurgical stays. RESULTS: During the 6-year study period from 1998 through 2003, the rate of S. aureus infection increased significantly for all inpatient stays (from 0.74% to 1.0%; annual percentage change (APC), 7.1%; P=.004), surgical stays (from 0.90% to 1.3%; APC, 7.9%; P=.001), and invasive orthopedic surgical stays (from 1.2% to 1.8%; APC, 9.3%; P<.001). For invasive neurosurgical stays, the rate of S. aureus infection did not change from 1998 to 2000 but increased at an annual rate of 11.0% from 2000 to 2003 (from 1.4% to 1.8%; P=.034). The total economic burden of S. aureus infection for hospitals also increased significantly for all stay types, with the annual percentage increase ranging from 9.2% to 17.9% (P<.05 for all). In 2003, the total economic burden of S. aureus infection was estimated to be $14.5 billion for all inpatient stays and $12.3 billion for surgical patient stays. However, there were significant decreases in the risk of S. aureus-related in-hospital mortality from 1998 to 2003 for all inpatient stays (from 7.1% to 5.6%; APC, -4.6%; P=.001) and for surgical stays (from 7.1% to 5.5%; APC, -4.6%; P=.002). CONCLUSIONS: The inpatient S. aureus infection rate and economic burden of S. aureus infections for US hospitals increased substantially from 1998 to 2003, whereas the in-hospital mortality rate decreased.     

Vessel-encoded arterial spin-labeling using pseudocontinuous tagging.

A new signal-to-noise ratio (SNR) efficient method is introduced for the mapping of vascular territories based on pseudocontinuous arterial spin labeling (ASL). A pseudocontinuous tagging pulse train is modified using additional transverse gradient pulses and phase cycling to place some arteries in a tag condition, while others passing through the same tagging plane are in a control condition. This is combined with a Hadamard or similar encoding scheme such that all vessels of interest are fully inverted or relaxed for nearly all of the encoding cycles, providing optimal SNR. The relative tagging efficiency for each vessel is measured directly from the ASL data and is used in the decoding process to improve the separation of vascular territories. High SNR maps of left carotid, right carotid, and basilar territories are generated in 6 min of scan time.     

Compensation for spin-lock artifacts using an off-resonance rotary echo in T1rhooff-weighted imaging.

The origin of image artifacts in an off-resonance spin-locking experiment is shown to be imperfections in the excitation flip angle. A pulse sequence for off-resonance spin locking is implemented that compensates for imperfections in the excitation flip angle through an off-resonance rotary echo. The off-resonance rotary echo alternates the frequency offset and phase of the RF transmitter during two spin-locking pulses of equal duration. The underlying theory is detailed, and MR images demonstrate the effectiveness of the technique in agarose gel phantoms and in in vivo human brain at 3T.     

The use of telescoping guide catheters for coronary sinus cannulation and sub-selecting tributaries in left ventricular lead placement

Introduction Failure to enter the coronary sinus (CS) with a guiding catheter and entering its tributaries remains challenging in left ventricle (LV) pacing lead implants for cardiac resynchronization therapy (CRT). A dual telescoping catheter system (8F outer/6F inner) is designed to provide the ability to adjust the catheter curve size, shape and/or reach to the patients’ anatomy avoiding the need for catheter change. Methods Five different designs for CS cannulation were randomly tested in 64 patients scheduled for CRT device implant. Results In 33 consecutive patients three adaptable telescoping guiding catheter systems were tested per patient, the adaptable catheters had higher overall cannulation success rates (68, 63 and 62%) compared to the fixed shape catheter (46%) and an greater cannulation success rate when the CS location was not known (70, 53 and 72% vs 33% for the fixed shape). In a second group of 31 CRT patients the two telescoping catheters had similar high levels of success (71–80%), with or without using the inner catheter. Conclusions The telescopic system is adaptable to a wide range of anatomical variations in patients and can result in a higher CS cannulation success rate due to its adjustability in the RA in search for the CS ostium. On top of this the inner catheter allows for sub-selecting the CS tributaries.     

Impact of major co-morbidities on mortality and complications after gastric bypass

BACKGROUND: We hypothesized that major co-morbidities affect survival and complications after gastric bypass. METHODS: A total of 1465 patients undergoing laparoscopic and open gastric bypass between 1995 and 2002 were studied. Patients with a body mass index >or= 35 kg/m(2) and major co-morbidities (group 1, n = 1045) were compared with patients with a body mass index >or= 40 kg/m(2) with minor/no co-morbidities (group 2, n = 420). RESULTS: Group 1 patients were older (43 versus 36 years, P < 0.001) and had a greater BMI (53 versus 50 kg/m(2), P < 0.001). Early postoperative complications were greater in group 1 than in group 2 and included leaks (4.1% versus 1.2%, P < 0.0032) and wound infections (3.9% versus 1.4%, P < 0.0133). Procedure-related mortality in the series was 1.7%. Mortality was 10-fold greater in group 1 (2.3% versus 0.2%, P < 0.0032). The incidence of small bowel obstruction, incisional hernia, and pulmonary embolism was similar in the two groups. Excess weight loss was significantly greater in group 2 (68% versus 62%, P < 0.001) at 1 year. Resolution of group 1 co-morbidities was great, including hypertension in 62%, diabetes in 75%, venous stasis disease in 96%, and pseudotumor cerebri in 98%. CONCLUSION: Outcomes analysis of obesity surgery requires risk stratification. The very low mortality rates in published studies are likely explained by surgical treatment of low-risk patients with minor co-morbidities, such as those seen in group 2. However, despite the increased perioperative risk, the group 1 patients (with major co-morbidities) demonstrated dramatic resolution of their co-morbid conditions, justifying the decision to go forward with surgery. The data support a radical change in treatment philosophy in which morbidly obese individuals should be offered bariatric surgery before major co-morbid conditions develop as a strategy to decrease the operative risk.     

Mortality risk associated with ejection fraction differs across resting nuclear perfusion findings.

BACKGROUND: Left ventricular ejection fraction (LVEF) is a significant predictor of morbidity and death. The nuclear summed rest score (SRS) measures myocardial perfusion defects and provides prognostic information, but its effects on long-term outcomes are not fully established. Moreover, information regarding the potential interaction between these 2 covariates is limited. The purpose of this study was to determine whether the mortality risk associated with LVEF is the same across all values of SRS in a population undergoing evaluation for ischemic heart disease. METHODS AND RESULTS: We examined 3,187 patients who underwent cardiac catheterization and perfusion single photon emission computed tomography imaging with a maximum follow-up of 8.1 years and median follow-up of 3.1 years. Cox proportional hazards modeling showed that increasing nuclear SRS and decreasing LVEF were independently associated with a higher long-term mortality rate, with a clinically significant interaction between them (P = .032). Patients with a normal LVEF and a high SRS (greater perfusion abnormality) have a prognosis similar to those with a reduced LVEF. CONCLUSIONS: Resting perfusion studies provide prognostic information for long-term survival and significantly impact the interpretation of mortality risk associated with changes in LVEF. Patient prognostication, risk stratification, and future research using these variables should take this interaction into account.     

BoneMorphing versus freehand localization of anatomical landmarks: consequences for the reproducibility of implant positioning in total knee arthroplasty.

OBJECTIVE: This study analyzed the influence of the acquisition method in image-free computer-assisted total knee arthroplasty (CAS-TKA), and the reproducibility of implant planning using BoneMorphing, a 3D morphometric model obtained by a 3D-to-3D elastic registration of statistical models to sparse point clouds acquired directly on the bone surface with a pointer. MATERIALS AND METHODS: Five surgeons (one expert, four trainees) each performed a CAS-TKA hybrid protocol based on morphometric models and landmarks on a cadaveric knee 10 times. In addition, several additional landmarks were digitized during each acquisition. The reproducibility of the implant positioning and sizing, as determined by an implant planning algorithm with morphometric models, was compared to direct digitization accuracy. RESULTS: Femoral and tibial implant positioning parameters with the hybrid protocol resulted in intra-surgeon standard deviations (SDs) of less than+/-1.4 degrees for rotation and 1.9 mm for translation for all surgeons in all directions except for tibial axial rotation (the only parameter determined by a digitized landmark and not recomputed in the 3D model). The variability in individual landmark digitization varied from 2 to 5 mm SD for certain landmarks, with ranges of 15-25 mm across all surgeons. The comparison study showed an improvement in femoral rotation reproducibility with the morphometric model when using the posterior condylar axis. Tibial implant reproducibility for each method was comparable, with the morphometric model giving better results in well-digitized areas such as the tibial plateau. CONCLUSION: A CAS-TKA protocol based on a deformed statistical model offers reproducible implant positioning. Some landmarks, such as distal condyles, show sufficient reproducibility in the direction of interest, while others, such as the anterior tibial tubercle, can lead to hazardous implant positioning. This should be taken into consideration when designing a CAS-TKA system with bony landmarks. In areas where a sufficient number of points have been digitized with good coverage, such as on the distal and posterior femoral condyles or the tibial plateau areas, the information derived from the 3D model is more accurate and reproducible than that derived from digitization. Good training and a guiding user interface are essential to guarantee coverage quality.     

Multipass Vector (Mpave) Technique with Nonablative Radiofrequency to Treat Facial and Neck Laxity

Background. Redundant facial and neck skin is a major feature of aging and historically has been corrected surgically. Recently, monopolar radiofrequency application has been introduced for nonablative tissue tightening of skin by volumetric heating of the deep dermis. It has been able to improve neck and cheek laxity and periorbital rhytides and to elevate eyebrows. However, questions remain as to the ideal parameters needed to optimize the use of radiofrequency.
Objective. To determine the safety and report on the efficacy of a radiofrequency application that involves a multipass vector (mpave) technique to target facial and neck skin laxity.
Methods. Twenty-five patients (skin types I to V) with mild to severe facial and neck laxity received one treatment session with monopolar radiofrequency. Treatment parameters, adverse events, and digital photographs were recorded. All patients were treated with a multipass vector technique consisting of four to five passes targeted over areas of skin that would most improve facial laxity. The multipass vector (mpave) treatment approach is described. Energy levels ranged from 62 to 91 J/cm2 per pulse.
Results. All patients experienced some immediate erythema and edema, which had completely resolved in most patients within 48 hours. No scarring or dyspigmentation was noted on follow-up at 6 and 12 weeks. Photographic analysis of pre- and post-treatment digital images revealed cosmetic improvement in facial and neck laxity in 96% of patients. The majority of patients demonstrated a moderate or better improvement. Stacked pulses in the submental region were shown to reduce fat.
Conclusions. The direct application of monopolar radiofrequency to facial and neck skin using a multipass vector (mpave) treatment approach was safely tolerated in patients of all skin types. Patient satisfaction correlated well with photographic analysis, and the technique was shown to be efficacious for most patients.