Publications

OBJECTIVE

To compare the accuracy of radiography and computed tomography (CT) in predicting implant position in relation to the vertebral canal in the cervical and thoracolumbar vertebral column.

STUDY DESIGN

In vitro imaging and anatomic study.

ANIMALS

Medium-sized canine cadaver vertebral columns (n=12).

METHODS

Steinmann pins were inserted into cervical and thoracolumbar vertebrae based on established landmarks but without predetermination of vertebral canal violation. Radiographs and CT images were obtained and evaluated by 6 individuals. A random subset of pins was evaluated for ability to distinguish left from right pins on radiographs. The ability to correctly identify vertebral canal penetration for all pins was assessed both on radiographs and CT. Spines were then anatomically prepared and visual examination of pin penetration into the canal served as the gold standard.

RESULTS

Left/right accuracy was 93.1%. Overall sensitivity of radiographs and CT to detect vertebral canal penetration by an implant were significantly different and estimated as 50.7% and 93.4%, respectively (P<.0001). Sensitivity was significantly higher for complete versus partial penetration and for radiologists compared with nonradiologists for both imaging modalities. Overall specificity of radiographs and CT to detect vertebral canal penetration was 82.9% and 86.4%, respectively (P=.049).

CONCLUSIONS

CT was superior to radiographic assessment and is the recommended imaging modality to assess penetration into the vertebral canal.

CLINICAL RELEVANCE

CT is significantly more accurate in identifying vertebral canal violation by Steinmann pins and should be performed postoperatively to assess implant position.

BACKGROUND

Post-myocardial infarction (MI) complications include ventricular tachycardia (VT). Excessive non-MI fibrosis, involving the infarct border zone (IBZ) and beyond, is an important substrate for VT vulnerability.

OBJECTIVE

This study assessed whether the antifibrotic agent pirfenidone can mitigate fibrosis in remodeling and determined its effects on myocardial function and VT susceptibility in a rodent MI model.

METHODS

We studied 2 groups of rats undergoing MI 1 week prior to treatment: a control group (n = 15) treated with placebo and a pirfenidone group (n = 15). We performed serial echocardiograms, and after 4 weeks of treatment, we conducted electrophysiological and optical mapping studies as well as histology.

RESULTS

There was less decline in left ventricular (LV) ejection fraction for pirfenidone-treated rats, 8.6% versus 24.3% in controls (P <0.01). Pirfenidone rats also had lower rates of VT inducibility, 28.6% versus 73.3% in control rats (P <0.05). Furthermore, pirfenidone-treated rats had faster conduction velocities in their IBZs compared with controls, at all pacing cycle lengths (P <0.05). Rats treated with pirfenidone also had smaller infarct dense scar (8.9% of LV myocardium vs. 15.7% in controls, P <0.014), less total LV fibrosis (15% vs. 30% in controls, P <0.003), and less nonscar fibrosis (6.6% vs. 12.6% in controls, P <0.006).

CONCLUSION

Pirfenidone decreased total and nonscar fibrosis in a rat MI model, which correlated with decreased infarct scar, improved LV function, and decreased VT susceptibility. Directly targeting post-MI fibrotic substrates may have a role in limiting infarct-dense scar, improving LV function, and reducing VT vulnerability.

BACKGROUND

Food insecurity is emerging as an important barrier to antiretroviral (ARV) adherence in sub-Saharan Africa and elsewhere, but little is known about the mechanisms through which food insecurity leads to ARV non-adherence and treatment interruptions.

METHODOLOGY

We conducted in-depth, open-ended interviews with 47 individuals (30 women, 17 men) living with HIV/AIDS recruited from AIDS treatment programs in Mbarara and Kampala, Uganda to understand how food insecurity interferes with ARV therapy regimens. Interviews were transcribed, coded for key themes, and analyzed using grounded theory.

FINDINGS

Food insecurity was common and an important barrier to accessing medical care and ARV adherence. Five mechanisms emerged for how food insecurity can contribute to ARV non-adherence and treatment interruptions or to postponing ARV initiation: 1) ARVs increased appetite and led to intolerable hunger in the absence of food; 2) Side effects of ARVs were exacerbated in the absence of food; 3) Participants believed they should skip doses or not start on ARVs at all if they could not afford the added nutritional burden; 4) Competing demands between costs of food and medical expenses led people either to default from treatment, or to give up food and wages to get medications; 5) While working for food for long days in the fields, participants sometimes forgot medication doses. Despite these obstacles, many participants still reported high ARV adherence and exceptional motivation to continue therapy.

CONCLUSIONS

While reports from sub-Saharan Africa show excellent adherence to ARVs, concerns remain that these successes are not sustainable in the presence of widespread poverty and food insecurity. We provide further evidence on how food insecurity can compromise sustained ARV therapy in a resource-limited setting. Addressing food insecurity as part of emerging ARV treatment programs is critical for their long-term success.

The 2 predominant causes of ventricular tachycardia (VT) arising from the right ventricle are arrhythmogenic right ventricular cardiomyopathy (ARVC) and idiopathic VT arising from the right ventricular outflow tract (RVOT). These arrhythmias can be adrenergically mediated and may be difficult to distinguish clinically. A minor criterion for the diagnosis of ARVC is T-wave inversion (TWI) in the right precordial leads during sinus rhythm. However, there have been reports of precordial TWI identified in patients with RVOT tachycardia. The purpose of this study was to determine whether patterns of precordial TWI could differentiate between the 2 groups. A multicenter registry of 229 patients with VT of right ventricular origin was evaluated. After appropriate exclusions (n = 29), 79 patients (58% men, mean age 40 +/- 14 years) had ARVC, and 121 patients (41% men, mean age 48 +/- 14 years) had RVOT tachycardia. During sinus rhythm, 37 patients (47%) with ARVC and 5 patients (4%) with RVOT tachycardia had TWI in leads V(1) to V(3). For the diagnosis of ARVC, TWI in leads V(1) to V(3) had sensitivity of 47% and specificity of 96%. In conclusion, in patients with VT of right ventricular origin, the presence of TWI in electrocardiographic leads V(1) to V(3) supports the diagnosis of ARVC.