The accuracy of two equations in normalizing total phenytoin concentrations in the presence of renal failure or hypoalbuminemia was evaluated in 11 renal failure and 23 hypoalbuminemic patients. Blood samples were obtained from hospitalized patients receiving phenytoin and were assayed for free and total phenytoin concentrations. Estimated normalized phenytoin concentrations based on free drug concentration were compared statistically with normalized concentrations calculated from the two equations via Student's t-test. The equation for normalizing phenytoin concentrations in hypoalbuminemic patients significantly underpredicted normalized phenytoin concentrations 15.7 ± 8.5 versus 19.9 ± 12.1 mg/L(p<0.001). In patients with renal failure, the mean phenytoin concentration from the respective equations and that based on free concentration were 14.1 ± 6.2 and 14.0 ± 7.9 mg/L, respectively. However, in 5 of 11 renal failure patients the equation resulted in over- or underprediction by at least 25 percent. Neither equation should be used clinically to normalize phenytoin concentrations in these patient populations.
Endovascular repair of recoarctation was indicated. For strategy optimization, a reconstruction and 3D printing model of the pathological aorta was performed (Figure 1).The procedure was carried out under neuroleptanalgesia, with continuous central monitoring of differential pressure and a rapid pacemaker during stent placement. An AltoSa-XL-Gemini Balloon Catheter of 18 mm diameter and 50 length (AndraTec GmbH, Koblenz, Germany) was used over which a self-expandable covered Andrastent 48XL stent (PTFE-tube covered cobalt-chromium stent with semi-open cell design, AndraMed GmbH, Reutlingen, Germany) was mounted. Once deployed, a control angiography was performed and differential arterial pressures were recorded in pull back. The covered stent was placed in the correct position, and the previous gradient of 60 mmHg was reduced to 15 mmHg (Figure 2).The patient was discharged three days after surgery with no antihypertensive drugs and with normal kidney function. At present, he walks three kilometers a day without claudication.Indications for surgery on a patient with recoarctation are the same as those for the native disease. Those indications include a transcoarctation pressure gradient >20 mmHg, persistent hypertension not attributable to other causes, radiological evidence of clinically significant collateral flow, heart failure associated with coarctation, or disabling intermittent claudication. (2) Although severe anemia may have been the precipitating factor of this patient's symptoms of claudication, management of blood pressure was difficult, as he was taking five antihypertensive drugs.Aneurysm or pseudoaneurysm is usually found distal
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