A randomized study of the safety and efficacy of fondaparinux versus placebo in the prevention of venous thromboembolism after coronary artery bypass graft surgery.

UNLABELLED: Venous thromboembolism (VTE) after coronary artery bypass graft (CABG) surgery may increase the postoperative morbidity and mortality. Therefore, we examined the current postoperative need for prophylactic antithrombotic therapy after CABG surgery. METHODS: This randomized, placebo-controlled, double-blind study was designed to compare the safety and efficacy of fondaparinux versus placebo in the prevention of VTE after CABG surgery. Between March 2010 and January 2013, 78 patients free from preoperative deep vein thrombosis (DVT) were enrolled, of whom 37 were randomly assigned to placebo and 41 to treatment with fondaparinux. The primary study end point was a composite, up to day 11, of (a) cumulative incidence of all VTE events, defined as symptomatic and asymptomatic DVT, and fatal and nonfatal pulmonary embolisms (efficacy end point), and (b) cumulative incidence of major hemorrhages (safety end point). RESULTS: A single asymptomatic DVT of a lower extremity was detected by duplex ultrasound at the time of discharge from the hospital in the placebo-treated group, and a single major postoperative hemorrhage occurred in the fondaparinux-treated group. CONCLUSIONS: The incidence of postprocedural asymptomatic DVT in this sample of patients undergoing CABG surgery was low. The overall incidence of DVT in the control and investigational treatment groups was similar. Our results showed no benefit of prophylactic postoperative fondaparinux in this population. These findings are congruent with other published studies and provide additional support for recent recommendations not to routinely use anticoagulant prophylaxis after cardiac surgery.

Vestibular perception and the vestibulo-ocular reflex in young and older adults.

OBJECTIVES: Quantification of the perceptual thresholds to vestibular stimuli may offer valuable complementary information to that provided by measures of the vestibulo-ocular reflex (VOR). Perceptual thresholds could be particularly important in evaluating some subjects, such as the elderly, who might have a greater potential of central as well as peripheral vestibular dysfunction. The authors hypothesized that perceptual detection and discrimination thresholds would worsen with aging, and that there would be a poor relation between thresholds and traditional measures of the angular VOR represented by gain and phase on rotational chair testing. DESIGN: The authors compared the detection and discrimination thresholds of 19 younger and 16 older adults in response to earth-vertical, 0.5 Hz rotations. Perceptual results of the older subjects were then compared with the gain and phase of their VOR in response to earth-vertical rotations over the frequency range from 0.025 to 0.5 Hz. RESULTS: Detection thresholds were found to be 0.69 ± 0.29 degree/sec (mean ± standard deviation) for the younger participants and 0.81 ± 0.42 degree/sec for older participants. Discrimination thresholds in younger and older adults were 4.83 ± 1.80 degree/sec and 4.33 ± 1.57 degree/sec, respectively. There was no difference in either measure between age groups. Perceptual thresholds were independent of the gain and phase of the VOR. CONCLUSIONS: These results indicate that there is no inevitable loss of vestibular perception with aging. Elevated thresholds among the elderly are therefore suggestive of pathology rather than normal consequences of aging. Furthermore, perceptual thresholds offer additional insight, beyond that supplied by the VOR alone, into vestibular function.

Temporal binding of auditory and rotational stimuli.

Integration of cues from multiple sensory channels improves our ability to sense and respond to stimuli. Cues arising from a single event may arrive at the brain asynchronously, requiring them to be "bound" in time. The perceptual asynchrony between vestibular and auditory stimuli has been reported to be several times greater than other stimulus pairs. However, these data were collected using electrically evoked vestibular stimuli, which may not provide similar results to those obtained using actual head rotations. Here, we tested whether auditory stimuli and vestibular stimuli consisting of physiologically relevant mechanical rotations are perceived with asynchronies consistent with other sensory systems. We rotated 14 normal subjects about the earth-vertical axis over a raised-cosine trajectory (0.5 Hz, peak velocity 10 deg/s) while isolated from external noise and light. This trajectory minimized any input from extravestibular sources such as proprioception. An 800-Hz, 10-ms auditory tone was presented at stimulus onset asynchronies ranging from 200 ms before to 700 ms after the onset of motion. After each trial, subjects reported whether the stimuli were "simultaneous" or "not simultaneous." The experiment was repeated, with subjects reporting whether the tone or rotation came first. After correction for the time the rotational stimulus took to reach vestibular perceptual threshold, asynchronies spanned from -41 ms (auditory stimulus leading vestibular) to 91 ms (vestibular stimulus leading auditory). These values are significantly lower than those previously reported for stimulus pairs involving electrically evoked vestibular stimuli and are more consistent with timing relationships between pairs of non-vestibular stimuli.