Elimination of iomeprol in patients undergoing continuous ambulatory peritoneal dialysis.
OBJECTIVE: To examine the elimination of iomeprol, its safety in clinical use, and its peritoneal permeability in continuous ambulatory peritoneal dialysis (CAPD) patients with variable degrees of residual renal function (RRF). DESIGN: A nonrandomized comparison study. SETTING: Hospitalized patients in CAPD unit of Chikuho and University Hospitals. PARTICIPANTS: Fourteen patients treated by CAPD and 6 by hemodialysis (HD). INTERVENTIONS: Total dialysate, blood, and 24-hour urine collections were obtained for 4 consecutive days after the administration of iomeprol. A peritoneal equilibration test was performed just before and after the administration of iomeprol. MEASUREMENTS: Iomeprol (iodine) concentration was measured. Residual renal function was estimated as the mean of renal creatinine and urea clearances. Dialysate-to-plasma ratios (D/P) of creatinine and iomeprol were also determined. RESULTS: In all CAPD patients, plasma iomeprol clearance was markedly slow, with a biological half-life (T1/2) of over 32 hours. However, no patients suffered from any adverse effects, and over 80% of plasma iomeprol was eliminated during the 4-hour HD. The plasma iomeprol elimination rate was significantly higher from 4 hours after the iomeprol administration in CAPD patients with RRF [mean estimated creatinine clearance (CCr) 3.8 mL/min, n = 7] compared to the remaining patients (mean estimated CCr 0.6 mL/min, n = 7); however, T1/2 in patients with RRF was over 24 hours. D/P creatinine was significantly correlated with D/P iomeprol, and peritoneal iomeprol permeability may depend on an individual's peritoneal solute transport properties. CONCLUSIONS: A prolonged elimination rate of iomeprol was documented in our CAPD patients both with and without RRF. A HD procedure or intensive peritoneal dialysis just after the use of iomeprol may be advisable to promptly remove circulating iomeprol. (+info)
Abdominal aortic aneurysm measurements for endovascular repair: intra- and interobserver variability of CT measurements.
OBJECTIVES: to evaluate the intra- and interobserver variability in measurements of the aorta and iliac arteries in patients with abdominal aortic aneurysms (AAAs) considered for endovascular repair using computed tomography angiography (CTA). METHODS: the diameter of the neck, aneurysm, right and left iliac artery were measured by 5 observers in 10 consecutive patients. Measurements were performed on hard copy using a ruler and on a workstation using an electronic caliper. RESULTS: the intraobserver variability showed a decrease going from hard copy to workstation in the standard deviation of the differences of the paired observations for the neck from 3.54 mm to 1.18 mm; for the aorta from 4.16 to 1.72 mm; for the right iliac from 1.87 to 1.01 mm; for the left iliac from 2.07 to 0.87 mm. The interobserver variability showed a similar decrease for the neck in all ten pairs of observers; for the aorta in two, for the right iliac and left iliac in five. However, the difference between observers regularly exceeded 2 mm. CONCLUSION: the use of a workstation and electronic calipers results in lower intra- and interobserver variability. However, the results still show a clinically relevant difference between the observers. Therefore, it is necessary to develop an automatic observer-independent measurement technique. (+info)
The risk of contrast media-induced ventricular fibrillation is low in canine coronary arteriography with ioxilan.
Previous studies have proposed that sodium supplement to nonionic contrast media (CM) can decrease the risk of ventricular fibrillation (VF). This study was designed to compare the occurence of VF induced by ioxilan (containing 9 mmol/LNa+) with other nonionic CMs. After wedging a catheter in the right coronary artery, test solutions including ioxilan, ioversol, iomeprol, and iopromide were infused for 30 sec at the rate of 0.4 ml/sec or until VF occurred. Then, incidence of VF, contact time (i.e. the time required to produce VF), and QTc were measured. Also, the CMs other than ioxilan were investigated at sodium levels adjusted to 9 and 20 mmol/L Na+. The incidence of VF with ioxilan (0%) was the lowest of all. In the other CMs, the incidence decreased in accordance with increase of sodium. Iomeprol and iopromide showed significant reduction of VF incidence at the sodium level of 20 mmol/L. The higher sodium supplements also prolonged the contact times. The increase of QTc was the greatest in ioxilan. Ioxilan has the least arrythmogenic property among the current low-osmolality nonionic CMs. This property might be attributable to an optimal sodium concentration of 9 mmol/L in the CM. (+info)
Descending aorta wall volume and coronary artery disease: a comparative study using enhanced computed tomography of the chest and coronary angiography.
The study examined the association between aortic wall volume (AWV) detected by enhanced computed tomography and coronary artery atherosclerosis observed on angiography. In 180 cases, AWV was measured as the total wall volume of a 7-cm portion of the descending thoracic aorta distal from the tracheal bifurcation. Coronary artery atherosclerosis was angiographically quantified by both Gensini score, in terms of the severity of coronary artery stenosis, and Extent score, in terms of the severity of coronary artery involvement. Mean AWV values between the patients with significant coronary artery stenosis and those without significant stenosis were 9.83+/-4.04 cm3 and 8.09+/-2.39 cm3, respectively (p<0.001). AWV was a significantly independent variable for significant coronary artery disease (p=0.0097) and an Extent score > or = 60 (p=0.0092). Calcification of AWV, however, was not associated with coronary atherosclerosis. The quantification of aortic atherosclerosis was useful for diagnosing coronary artery disease. (+info)
Proximal tubule cell response to radiographic contrast media.
Renal dysfunction associated with contrast media (CM) administration is generally attributed to reduced renal blood flow. Studies, however, also suggest direct tubular effects of CM, whose mechanisms remain unclear. This study was conducted to assess the chemotoxic effects of iopamidol, a prototypic CM, on a porcine proximal tubule (PT) cell line, LLC-PK(1) cells. Results indicate that iopamidol did not affect cell viability (determined by trypan blue exclusion and fluorescein staining), but did reduce cell proliferation. Moreover, iopamidol altered mitochondrial function, as determined by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction and mitochondrial membrane potential. Decreased MTT reduction was evident with all CM tested, and its rapid recovery after CM removal suggests that inhibition of mitochondrial function is reversible. Injury to PT cells by iopamidol is supported by the fact that CM increase extracellular adenosine, an indicator of cellular stress. This study provides greater insight into the mechanism underlying the nephrotoxicity induced by contrast in patients and explains the reversibility of this toxicity. (+info)
Postinfarctional remodeling: increased dye intensity in the myocardial risk area after angioplasty of infarct-related coronary artery is associated with reduction of ventricular volumes.
OBJECTIVES: We sought to evaluate if angiographic dye videointensity of the risk area during percutaneous transluminal coronary angioplasty (PTCA) of the infarct-related artery (IRA) relates to remodeling. BACKGROUND: Poor reflow after myocardial infarction (MI) predicts worse ventricular remodeling. METHODS: Fifty-three patients with a first anterior MI and isolated disease of the left anterior descending (LAD), who underwent "primary" (n = 14), "rescue" (n = 7) or "late" (after 10 +/- 4 days, n = 32) PTCA, were retrospectively selected. In 10 patients prospectively collected, we assessed Doppler flow velocities and Doppler flow reserve (DFR), relating them to the videointensity technique. Coronary stenosis and TIMI flow were determined, and echocardiographic volumes (end-diastolic and end-systolic volume indexes) and regional asynergy were computed before hospital discharge (baseline) and at six months. Assuming higher peak videointensity reflects greater myocardial blood volume, a 1- to 5-point (poor-optimal) perfusion scale was devised. RESULTS: The correlation of Doppler peak velocity and DFR with videointensity was significant (r = 0.58, p = 0.007 and r = 0.71, p < 0.001, respectively). Patients were subdivided into group A (increased videointensity post-PTCA > or = 1.5 points, n = 29) and group B (unchanged videointensity, n = 24). Analysis of variance showed a time-group interaction for end-diastolic volume index (-4.6 +/- 23% vs. +22 +/- 22%, p = 0.003) and end-systolic volume index (-3.05 +/- 11.1% vs. +4.1 +/- 12.5%, p = 0.027). There was no interaction for changes in LAD stenosis (p = 0.39) and TIMI flow after PTCA (p = 0.27), or regional asynergy at six months (p = 0.31). CONCLUSIONS: Angiographic dye videointensity in the risk area correlates with Doppler peak velocity and DFR, and its increase after PTCA of IRA has a limiting effect on ventricular volumes, independent of coronary stenosis resolution, changes in Thrombolysis In Myocardial Infarction (TIMI) flow or extent of regional asynergy. (+info)
Effects of nonionic contrast media on platelet aggregation: assessment by particle counting with laser-light scattering.
Intravascular radiographic contrast media used in angiography, particularly nonionic contrast media, may cause activation of platelets. This study was designed to determine which properties of nonionic contrast media were potentially responsible for this action. Platelet aggregation after adenosine diphosphate stimulation was studied in the platelet rich plasma obtained from 37 patients who underwent left ventriculography using the highly sensitive method of particle counting with laser-light scattering. Platelet activation by contrast media was studied in the platelet rich plasma from healthy volunteers using flow cytometric analysis to detect platelet degranulation as P-selectin expression. There was a significant decrease in platelet aggregation in patients injected with ioxilan or iomeprol compared with patients injected with iohexol. There was a significant increase in P-selectin expression with the three groups of contrast media compared to control. The platelet activation with ioxilan or iomeprol was significantly less compared to the activation with iohexol. The comparison showed that previous generalization regarding platelet activation by nonionic contrast media might not be valid. It is presumed that the higher osmolality of iohexol may contribute to the increase in platelet aggregation and activation. (+info)
Assessment of Fallopian tube patency by HyCoSy: comparison of a positive contrast agent with saline solution.
OBJECTIVE: To compare the efficiency of air-filled albumin microspheres (Infoson) with saline solution in determining Fallopian tube patency during hysterosalpingo contrast sonography (HyCoSy). METHODS: This was a prospective randomized multicenter study with a sequential design. Over a 10-month period, 23 patients (mean age, 33 years) referred for infertility were examined by HyCoSy (saline or Infoson) before conventional hysterosalpingography (Iopamiron 370), performed during the same session. Contrast agents were administered through a 5-F Ackrad balloon catheter inserted transcervically into the uterine cavity. HyCoSy was performed with a 7-MHz transvaginal probe using both B-mode and color Doppler, and tubal patency was demonstrated by the appearance of contrast agent in the peritoneal cavity near the ovaries. Data were registered for each patient during the examination and the results were monitored by sequential analysis. RESULTS: Mean volumes of contrast injections were 35.3 mL of saline, 14.4 mL of Infoson, and 13.8 mL of Iopamiron 370. Infoson-enhanced HyCoSy provided a significantly larger (P = 0.006) number of correct diagnoses (20/22 Fallopian tubes) than did saline HyCoSy (12/24 Fallopian tubes), and the same number as that achieved by hysterosalpingography. CONCLUSION: A positive ultrasound contrast agent appears to be more efficient than saline solution at determining Fallopian tube patency in infertile women by means of HyCoSy, and as efficient as an iodinated contrast agent in the same population explored by HSG. HyCoSy could be used to screen infertile women, thereby avoiding the use of iodinated contrast medium and exposure to ionizing radiation during conventional HSG in patients with patent Fallopian tubes. (+info)