Objective performance goals of safety and blood pressure efficacy for clinical trials of renal artery bare metal stents in hypertensive patients with atherosclerotic renal artery stenosis

Objective : To provide safety and performance goals for prospective single‐arm trials of bare metal renal artery stenting in patients with resistant hypertension associated with high grade atherosclerotic renal artery stenosis. Background : To date, there have been no US Pre‐Market Approval (PMA) bare metal renal stent device trials which have focused on improvement of blood pressure control as a primary effectiveness endpoint. Methods : Analysis of subject‐level data from three large industry sponsored pre‐market approval (PMA) trials was performed. Hypertensive patients (≥155 mmHg) with a ≥50% atherosclerotic renal artery stenosis were included. Thirty day and 9‐month systolic and diastolic blood pressure measurements, renal function and 9‐month duplex ultrasound assessment of renal artery patency were analyzed. Results : Initial data analysis of 600 patients from the 3 PMA trials identified 286 patients who met inclusion criteria. The mean baseline systolic blood pressure was 177.8 ± 19.3 mmHg with a mean 68.1% diameter renal artery stenosis. Nine months after successful stenting, the mean SBP was 156.7 ± 24.1 mmHg; the 9 month restenosis rate was 14.4%. Conclusion : Based on the statistical modeling of these data and a priori established performance criteria, the co‐primary endpoints of 9 month reduction in blood pressure and in‐stent restenosis are proposed. The reduction in blood pressure will be analyzed as a continuous variable and will be compared to this performance goal. © 2011 Wiley‐Liss, Inc.     

Open-source,vendor-independent,automated multi-beat tissue Doppler echocardiography analysis

Current guidelines for measuring cardiac function by tissue Doppler recommend using multiple beats, but this has a time cost for human operators. We present an open-source, vendor-independent, drag-and-drop software capable of automating the measurement process. A database of ~8000 tissue Doppler beats (48 patients) from the septal and lateral annuli were analyzed by three expert echocardiographers. We developed an intensity- and gradient-based automated algorithm to measure tissue Doppler velocities. We tested its performance against manual measurements from the expert human operators. Our algorithm showed strong agreement with expert human operators. Performance was indistinguishable from a human operator: for algorithm, mean difference and SDD from the mean of human operators’ estimates 0.48?±?1.12 cm/s (R²?=?0.82); for the humans individually this was 0.43?±?1.11 cm/s (R²?=?0.84), ?0.88?±?1.12 cm/s (R²?=?0.84) and 0.41?±?1.30 cm/s (R²?=?0.78). Agreement between operators and the automated algorithm was preserved when measuring at either the edge or middle of the trace. The algorithm was 10-fold quicker than manual measurements (p?<?0.001). This open-source, vendor-independent, drag-and-drop software can make peak velocity measurements from pulsed wave tissue Doppler traces as accurately as human experts. This automation permits rapid, bias-resistant multi-beat analysis from spectral tissue Doppler images.     

Effect of Acute Pain on Splenic NK Cell Activity,Lymphocyte Proliferation and Cytokine Production Activities

Various types of physical and physiological stress in animals have been shown to affect their humoral and cell-mediated immune responses. The present study was designed to investigate the possible influence of acute pain on the immune system. BALB/c mice were exposed to an increasing number of heat shocks using a Tail Flick apparatus; an equal number of control mice received no shock treatments. After each of the regimens was completed, the spleen of each mouse was recovered and various cell populations isolated to assess: the proliferative response to phytohemagglutinin by lymphocytes; cytotoxic activities of natural killer (NK) cells; and, the production of select important cytokines by splenic lymphocytes. The results indicated that NK cell activity and proliferation of lymphocytes were significantly (p < 0.001) increased due to the shock regimens after only a single day's rounds of stimulation (i.e., 3 rounds of ≈12 equally time-spaced shocks/hr with 30–45 min gap between rounds). After 2 and 3 days' rounds of stimulations, no significant changes were detected in the proliferative response of isolated lymphocytes; conversely, the activity of NK cells remained significantly elevated compared to the controls hosts' cells, even on the second day of stimulation but not on the third. Regarding effects on cytokines, no significant changes were detected in the amount of Interferon-γ (IFNγ) and Interlukin-10 (IL-10) produced by lymphocytes obtained from the spleens of any of the shocked mice. These results could suggest that certain acute stressors might actually strengthen a host's immunological reactivity and, possibly, result in an enhanced capacity to resist pathogens that might infect the body.