Comparison of squatting stress echocardiography and dobutamine stress echocardiography for the diagnosis of coronary artery disease

Background: Dobutamine stress echocardiography (DSE) is commonly used for the diagnosis for coronary artery disease (CAD). We previously demonstrated that squatting induces wall motion abnormalities (WMA) in areas subtended by stenotic coronary arteries. Objective: This study was designed to test the hypothesis that dobutamine and squatting stress echocardiography are equally useful for the diagnosis of CAD. Methods: We studied 39 patients who were scheduled to have coronary angiography for the evaluation of chest pain. Each patient had squatting stress echocardiography followed by DSE. For squatting stress echocardiography the echocardiogram in standard views was recorded in the standing position. The procedure was repeated during squatting for 2 minutes. Dobutamine echocardiography was performed using standard protocol. The squatting and dobutamine stress echocardiograms were interpreted by an observer blinded to the results of coronary angiography. Results: During squatting, new or worsening WMA developed in 20 patients. Six patients developed WMA in the left anterior descending artery territory, three in circumflex territory, three in the right coronary artery territory, and eight in multiple coronary territories. The sensitivity, specificity, and accuracy of squatting echocardiography for diagnosis of CAD were 95%, 94%, and 94%, respectively. For DSE, the sensitivity, specificity, and accuracy for the diagnosis of CAD were 85%, 94%, and 90%, respectively. There was no significant difference between squatting and dobutamine stress echocardiography for the diagnosis of CAD (P = 0.702). Conclusion: These data indicate that squatting and dobutamine echocardiography are equally useful in the diagnosis of CAD. In selected patients, squatting echocardiography may be used in place of dobutamine echocardiography for the diagnosis of CAD. (Echocardiography 2012;29:695–699)     

Stress‐induced reduction in hippocampal volume and connectivity with the ventromedial prefrontal cortex are related to maladaptive responses to stressful military service

Previous studies have shown that people who develop psychopathology such as posttraumatic stress disorder (PTSD) following stress exposure are characterized by reduced hippocampal (HC) volume and impaired HC functional connectivity with the ventromedial prefrontal cortex (vmPFC). Nevertheless, the exact interrelationship between reduced HC volume and HC‐vmPFC connectivity deficits in the context of stress has yet to be established. Furthermore, it is still not clear whether such neural abnormalities are stress induced or precursors for vulnerability. In this study, we combined measurements of MRI, functional MRI (fMRI), and diffusion tensor imaging (DTI) to prospectively study 33 a priori healthy Israeli soldiers both pre‐ and post‐exposure to stress during their military service. Thus, we were able to assess the contributions of structural and functional features of the HC and its connectivity to the onset and progression of maladaptive response to stress (i.e., increased PTSD symptoms post‐exposure). We found that soldiers with decreased HC volume following military service (i.e., post‐exposure) displayed more PTSD‐related symptoms post‐exposure as well as reduced HC‐vmPFC functional and structural connectivity post‐exposure, compared to soldiers with increased HC volume following military service. In contrast, initial smaller HC volume pre‐exposure did not have an effect on any of these factors. Our results therefore suggest that reduction in HC volume and connectivity with the vmPFC together mark a maladaptive response to stressful military service. As stress‐induced HC volume reductions were previously shown to be reversible, these localized biological markers may carry valuable therapeutic potential. Hum Brain Mapp 34:2808–2816, 2013. © 2012 Wiley Periodicals, Inc.     

Sleep Apnea: Is Routine Preoperative Screening Necessary?

Background

Because perioperative complications of unrecognized obstructive sleep apnea (OSA) can be severe, many bariatric surgery programs routinely screen all patients. However, many obese non-bariatric surgery patients do not get screened. We wanted to evaluate the need for routine preoperative OSA screening.

Methods

Morbidly obese patients with a body mass index (BMI)?>?40 kg/m² undergoing bariatric surgery—all screened for OSA—were compared to morbidly obese orthopedic lower extremity total joint replacements (TJR) patients—not screened for OSA. Cardio-pulmonary complications were recorded.

Results

Eight hundred eighty-two morbidly obese patients undergoing either bariatric (n?=?467) or orthopedic TJR surgery (n?=?415) were compared. As a result of screening, 119 bariatric surgery patients (25.5 %) were newly diagnosed with OSA, bringing the incidence to 42.8 % (200/467). Orthopedic surgery group had 72 of 415 (17.3 %) patients with pre-existing OSA. The unscreened orthopedic patients had a 6.7 % (23/343) cardiopulmonary complications rate compared to 2.6 % (7/267) for screened bariatric surgery patients. This difference was not statistically significant when adjusted for age and comorbidity (p?=?0.3383).

Conclusion

Sleep apnea screening prior to bariatric surgery identifies an additional 25 % of patients as having OSA. In this study, unscreened morbidly obese patients did not have an increased incidence of cardiopulmonary complications after surgery compared to screened patients. Prospective randomized studies should be conducted to definitively assess utility and cost effectiveness of routine OSA screening of all morbidly obese patients undergoing surgery. Preoperative OSA screening may be safely omitted when randomizing patients for such a trial.     

Failure of the first step of two-stage revision due to polymicrobial prosthetic joint infection of the hip

Background

The unsuccessful treatment of prosthetic joint infection (PJI) with two-stage revision leads to infection recurrence. The objectives of the study were to assess the clinical and demographic characteristics of patients with polymicrobial PJI, and to evaluate the role of the microbial profile involved in PJI in the risk of infection recurrence after the first step of two-stage revision surgery.

Materials and methods

A retrospective analysis of 189 cases of culture-positive PJI following total hip replacement over a 5-year period was performed. The demographic characteristics of patients, clinical symptoms, microbiology cultures of intraoperative biopsies, laboratory values of C-reactive protein (CRP), white blood cell count and erythrocyte sedimentation rate were analyzed. Patients were divided into two groups—135 with monomicrobial and 54 with polymicrobial infection.

Results

Of all patients, 68.9 % in the monomicrobial and 83.3 % in the polymicrobial group had a body mass index >25 kg/m² (p = 0.05). The median CRP values were 5.7 mg/L (IQR 4.0–10.0 mg/L) in the monomicrobial compared to 8.8 mg/L (IQR 5.0–27 mg/L) in the polymicrobial group (p = 0.01). The percentage of successful outcomes was 27.8 % in patients with microbial associations (p < 0.0001). Gram-negative pathogens caused polymicrobial PJI in 61.5 % of cases with infection recurrence (OR 4.4; 95 % CI 1.18–16.37; p = 0.03).

Conclusions

Overweight and obese patients or those with elevated CRP had a greater risk of polymicrobial PJI. They were predisposed to recurrence of infection after the first step of two-stage revision. An unsuccessful outcome was more likely in cases with polymicrobial infection compared to those with monomicrobial infection. In addition, the presence of multidrug-resistant strains of Gram-negative bacteria substantially increased the risk of PJI treatment being unsuccessful.

Level of evidence

Level III, therapeutic study.

     

Longitudinal Model of Periprosthetic Joint Infection in the Rat

The majority of periprosthetic joint infections occur shortly after primary joint replacement (<3 months) and require the removal of all implant components for the treatment period (~4 months). A clinically relevant animal model of periprosthetic infection should, therefore, establish an infection with implant components in place. Here, we describe a joint replacement model in the rat with ultrahigh molecular weight polyethylene (UHMWPE) and titanium components inoculated at the time of surgery by methicillin-sensitive Staphylococcus aureus (S. aureus), which is one of the main causative microorganisms of periprosthetic joint infections. We monitored the animals for 4 weeks by measuring gait, weight-bearing symmetry, von Frey testing, and micro-CT as our primary endpoint analyses. We also assessed the infection ex vivo using colony counts on the implant surfaces and histology of the surrounding tissues. The results confirmed the presence of a local infection for 4 weeks with osteolysis, loosening of the implants, and clinical infection indicators such as redness, swelling, and increased temperature. The utility of specific gait analysis parameters, especially temporal symmetry, hindlimb duty factor imbalance, and phase dispersion was identified in this model for assessing the longitudinal progression of the infection, and these metrics correlated with weight-bearing asymmetry. We propose to use this model to study the efficacy of using different local delivery regimens of antimicrobials on addressing periprosthetic joint infections. Statement of clinical significance: We have established a preclinical joint surgery model, in which postoperative recovery can be monitored over a multi-week course by assessing gait, weight-bearing, and allodynia. This model can be used to study the efficacy of different combinations of implant materials and medication regimens. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:1101-1112, 2020