Renal sympathetic denervation using the second generation EnligHTN Renal Denervation System resulted in safe, rapid, and significant mean office blood pressure reduction that was sustained through 24 months. Future studies will need to address the utility of this system against an appropriate sham based comparator.
The ability to measure aortic valve area clinically has emphasized the need to understand the changes in aortic valve orifice area during flow. To compare the performance of normal and stenotic human aortic valves we used a pulsatile flow model that simulated in vivo flow conditions. Five normal autopsy specimens and 15 stenotic valves removed at operation were mounted into the model. Valve function was assessed by analysis of video recordings of valve leaflet motion during flow. Over the flow rates tested normal valves demonstrated a linear increase in orifice area. There was no resistance to leaflet opening and valve closure was rapid. The majority of stenotic valves demonstrated an increase in orifice area at low flow rates. No valve showed any increase in maximal area beyond flow rates of 3 l min-1. Increased leaflet resistance of these abnormal valves resulted in notably slower opening and closing rates. In patients with a high cardiac output and severe stenosis, overestimation of the anatomic orifice area derived by the Gorlin equation can result. This is not related to variability in maximal orifice area.
Background:
Acute kidney injury (AKI) can be a major complication of transcatheter aortic valve replacement (TAVR). Atheroembolization of debris during catheter manipulation has been considered as a potential factor causing AKI. This study investigates the impact of aortic atheroma burden on AKI post-TAVR and evaluates the potential of preoperative multislice computed tomographic (MSCT) imaging for the assessment of AKI in these patients.
Methods and Results:
Preoperative multislice computed tomographic images were analyzed in 278 patients with symptomatic severe aortic stenosis who underwent TAVR. AKI was defined as an absolute increase in serum creatinine ≥0.3 mg/dL. Aorta vessel and lumen areas in each 1-mm cross-sectional image were measured. Percent atheroma volume above (PAV
above renal arteries
) and below (PAV
below renal arteries
) renal arteries were calculated by the following formula: PAV={Σ (vessel area−lumen area)/Σ(vessel area)}×100. AKI occurred in 92 patients (33.1%) after TAVR. AKI was associated with a greater PAV above (30.4±8.2 versus 21.3±5.8%;
P
=0.02) but not below (28.9±7.7 versus 25.8±6.1%;
P
=0.41) the renal arteries. Greater PAV
above renal arteries
was associated directly with AKI severity (
P
=0.008) and inversely with recovery in serum creatinine level from peak to discharge (
r
=0.78;
P
=0.002). Multivariate analysis demonstrated that PAV
above renal arteries
was a significant predictor of AKI (
P
=0.02). Receiver-operating curve analysis identified PAV
above renal arteries
>29.5% as an optimal threshold to predict AKI.
Conclusions:
Suprarenal aortic atheroma burden is associated with the occurrence, severity, and recovery of AKI after TAVR. This highlights the utility of preoperative assessment of aortic atherosclerosis on multislice computed tomography to identify patients at high-risk for AKI.
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