Publications

OBJECTIVE

Delayed enhancement MRI using fast segmented k-space inversion recovery (IR) gradient-echo imaging is a well established "bright-blood" technique for identifying myocardial infarction and is used as the reference standard sequence in this study. The purpose of this study was to validate a recently developed dark blood-pool delayed enhancement technique in a porcine animal model, evaluate its performance in human patients, and quantify its performance compared with the reference standard in both.

SUBJECTS AND METHODS

In an animal study, the reference standard and dark blood-pool delayed enhancement were assessed in three pigs with induced myocardial infarction. In a human study, 26 patients, 31-81 years old (19 men and seven women), with a known history of myocardial infarction were imaged using the reference standard and dark blood-pool delayed enhancement. Contrast-to-noise ratio (CNR), signal intensity ratio, signal-to-noise ratio (SNR), and qualitative scores of hyperenhancement were recorded. Measurements were compared using paired samples t test and Wilcoxon's signed rank test.

RESULTS

In the animal study, the mean CNR of infarct to blood pool was 11 times higher for dark blood-pool delayed enhancement than for the reference standard. The mean SNR was 4.4 times higher for the reference standard. In the human study, the mean CNR and signal intensity ratio of hyperenhancing myocardium to the blood pool were 1.9 (p = 0.04) and 5.5 (p < 0.01) times higher, respectively, for dark blood-pool delayed enhancement compared with reference standard. The mean CNR and signal intensity ratio of hyperenhancing myocardium to normal myocardium and SNR were 2.8 (p < 0.01), 1.3 (p = 0.07), and 2.8 (p < 0.01) higher, respectively, for the reference standard. Qualitative analysis identified seven extra segments with grade 1 scars using dark blood-pool delayed enhancement (p < 0.01).

CONCLUSION

Dark blood-pool delayed enhancement is complementary to the reference standard. It can detect more subendocardial foci of hyperenhancement, thus potentially identifying more infarcts and changing patient management.

BACKGROUND

Access to effective family planning is of great importance for women with sickle cell disease (SCD) due to the increased frequency of pregnancy complications. However, little is known regarding use of hormonal contraception, complications of contraception, and pregnancy in young women with SCD.

STUDY DESIGN

We abstracted diagnostic codes, procedure codes and pharmacy claims from women with SCD, aged 13-21 years, enrolled in Michigan Medicaid between 1/1/2000 and 12/31/2003 with ≥ 9 months of continuous eligibility.

RESULTS

We identified 250 women with SCD with an average period of continuous Medicaid enrollment of 20 months. Claims for hormonal contraception could be identified in only 20 patients (8%, 95% CI 5-12%). The most commonly prescribed method (n=12) was depot medroxyprogesterone (DMPA) acetate. Venous thromboembolism and osteopenia were rarely identified (n ≤ 10) and occurred only in women with no recorded use of hormonal contraception. In the total population, 64 patients had one pregnancy and 16 had ≥ 2 pregnancies during the 4-year study period. Among adolescents (13-18 years), 49 (30%) of 195 patients (95% CI 24-37%) had 59 pregnancies. By 12 weeks postpartum, few patients (n ≤ 10) with a record of delivery had hormonal contraception claims.

CONCLUSIONS

In a publicly insured population of young women with SCD, pregnancy was more commonly identified than hormonal contraception use. Our work suggests that significant gaps may exist in family planning care for young women with SCD.

Health experts emphasize that getting doctors to follow clinical guidelines can save both lives and money. Less attention has been paid to how the guidelines are developed and the variability in the recommendations they include. We examined the quality and content of screening guidelines as a proxy for guidelines in general and found that the source of the guidelines affects their quality. Guidelines with inconsistent recommendations are unlikely to serve patients or physicians well. The creation of an independent organization that would work with multiple stakeholders to develop guidelines holds the potential to improve their quality.

BACKGROUND

Identifying viral and host determinants of HIV-1 elite control may help inform novel therapeutic and/or vaccination strategies. Previously, we observed decreased replication capacity in controller-derived viruses suggesting that fitness consequences of human leukocyte antigen (HLA) class I-associated escape mutations in Gag may contribute to this phenotype. This study examines whether similar functional defects occur in Pol proteins of elite controllers.

METHODS

Recombinant NL4-3 viruses encoding plasma RNA-derived reverse transcriptase-integrase sequences from 58 elite controllers and 50 untreated chronic progressors were constructed, and replication capacity measured in vitro using a green fluorescent protein (GFP) reporter T-cell assay. Sequences were analyzed for drug resistance and HLA-associated viral polymorphisms.

RESULTS

Controller-derived viruses displayed significantly lower replication capacity compared with those from progressors (P < 0.0001). Among controllers, the most attenuated viruses were generated from individuals expressing HLA-B*57 or B*51. In viruses from B*57+ progressors (n = 8), a significant inverse correlation was observed between B*57-associated reverse transcriptase-integrase escape mutations and replication capacity (R = -0.89; P = 0.003); a similar trend was observed in B*57+ controller-derived viruses (n = 20, R = -0.36; P = 0.08).

CONCLUSIONS

HIV-1 Pol function seemed to be compromised in elite controllers. As observed previously for Gag, HLA-associated immune pressure in Pol may contribute to viral attenuation and subsequent control of viremia.

AIMS

The use of surgical antibiotic prophylaxis (AP) in children is poorly characterized. The aims of this study were to examine (1) trends in the use of AP for commonly performed operations, (2) appropriateness in the context of available guidelines, and (3) adverse events potentially attributable to AP.

METHODS

We conducted a 5-year retrospective analysis of 22 children's hospitals (January 2005-March 2009) for all patients younger than 18 years who underwent 1 of the 40 commonly performed general and urological procedures. Indications for AP were defined by published specialty-specific guidelines. Clostridium difficile infection and surrogate events for drug allergy (diphenhydramine and epinephrine administrations) were examined as potential antibiotic-associated adverse events.

RESULTS

Procedures of 246,316 were identified, of which 25% met criteria for AP. Eighty-two percent of the children received antibiotics during procedures when AP was indicated (range, 60%-96% by hospital), and 40% of the patients received antibiotics when there was no indication (range, 10%-83%). The likelihood of receiving AP was significantly different between hospitals for all procedures examined (P < .0001 for each procedure). Adverse events were significantly more frequent in children receiving AP than in those who did not (odds ratio [95% confidence interval] C difficile: 18.8 [6.9-51.5], P < .0001; epinephrine: 1.8 [1.7-2.0], P < .0001; diphenhydramine: 6.0 [5.6-6.5], P < .0001).

CONCLUSIONS

Significant variation exists in the use of AP in the pediatric surgical population. Many children do not receive AP when indicated, and an even greater proportion may receive antibiotics when there is no indication. These findings may have profound implications from a public health perspective when extrapolated to all children undergoing surgical procedures.