CT-Based Determination of Maximum Ureteral Stone Area: A Predictor of Spontaneous Passage

The Journal of Emergency Medicine Comments: This study was limited by its retrospective design and by its reliance on data from a database that did not include renal injury grading identical to what the authors used to stratify the patients in the study. Thus, the authors needed to stratify the patients based on what data had been input rather than relying on classifications made by the actual treating physicians. Still, these results seem to suggest a benefit of conservative management for more severe renal injuries. This does not necessarily mean that such patients would have to be transferred if the same care could be given at all centers. , CT-BASED DETERMINATION OF MAXIMUM URETERAL STONE AREA: A PREDICTOR OF SPONTANEOUS PASSAGE. Demehri S, Steigner ML, Sodickson AD, et al. AJR Am J Roentgenol 2012;198:603–8. This study measured stone area to predict spontaneous passage of ureteral stones and evaluated whether stone area was a more accurate predictor than stone diameter. They retrospectively reviewed 211 consecutive Emergency Department patients with acute flank pain due to ureteral stones diagnosed using unenhanced computed tomography. They evaluated two principal methods of calculating stone area, one using a fixed attenuation threshold (FTM) and the other using variable attenuation (VTM), in addition to measuring maximal axial diameter with both soft-tissue and bone window settings. Receiver operating characteristic analysis was used to compare the accuracy of maximum axial area with maximum axial diameter measurements for predicting spontaneous passage. Area under the curve (AUC) measurements (AUC = 0.84 and 0.83 using VTM and FTM, respectively) were more accurate than diameter measurements (AUC = 0.8 and 0.79 in bone and soft-tissue window settings, respectively) in predicting spontaneous passage. Even though area measurements were more accurate in predicting stone passage, there was only an overall 3–5% improvement in AUC compared with axial stone diameter. More predictive stone passage benefit from stone area was found among stones between 5 and 10 mm in which there was an overall 6–9% improvement in AUC compared with axial stone diameter. [Douglas Melzer, MD Denver Health Medical Center, Denver, CO] Comments: Although limited by its retrospective nature, this study suggests that calculating the area of a ureteral stone offers a slightly improved predictive accuracy of stone expulsion than does the measurement of its diameter. With such a small difference in accuracy, it is unclear if this technique would really add very much to the evaluation of these patients and suggests that the shape of the stone is no more important than the maximal diameter in predicting whether or not it will pass. , INFLUENCE OF DIABETES MELLITUS ON CLINICAL OUTCOMES FOLLOWING PRIMARY PERCUTANEOUS CORONARY INTERVENTION IN PATIENTS WITH ST-SEGMENT ELEVATION MYOCARDIAL INFARCTION. Jensen LO, Maeng M, Thayssen P, et al. Am J Cardiol 2012;109:629–35. This study compared outcomes after percutaneous coronary intervention (PCI) after ST-segment elevation myocardial infarction (STEMI) in patients with diabetes mellitus (DM) com-

749 pared to those without DM. The study was conducted using the Western Denmark health care databases, which covers 3.0 million inhabitants. Specifically, the study used the Western Denmark Heart Registry to identify all STEMIs treated with primary PCI using either drug-eluting stent or bare-metal stent from January 2002 through June 2005. Patients were followed for 36 months. Exclusion criteria were angioplasty without stent implantation or placement of a combination of drug-eluting and bare-metal stents. Patients were considered to have DM if their Heart Registry records indicated receipt of dietary treatment, oral anti-diabetic medication, or insulin. Researchers used Cox proportional-hazards regression to compute hazard ratios (HR) and controlled for age, gender, stent type (bare-metal or drug-eluting), procedure time, and Charlson Co-morbidity Index. In analysis of stent thrombosis and target lesion revascularization (TLR), researchers also adjusted for glycoprotein IIb/ IIIa receptor blocker use, stent length, and reference vessel size. A total of 3655 patients with STEMI treated with primary PCI were followed. Of these, 316 (8.6%) with 380 lesions had DM. Three-year rates of myocardial infarction were 12.3% in the DM group vs. 5.6% in the non-DM group (adjusted HR 2.56, 95% confidence interval [CI] 1.81–3.61). Rates of TLR were 12.1% in the DM group and 8.7% in the non-DM group (adjusted HR 1.55, 95% CI 1.14–2.11). All-cause mortality was 23.7% in patients with DM, vs. 12.7% in patients without DM (adjusted HR 2.03, 95% CI 1.59–2.59). The rates of definite stent thrombosis were not different between groups. [Omeed Saghafi, MD Denver Health Medical Center, Denver, CO] Comment: Although limited by its retrospective design, this study suggests a significant worsening in outcomes in patients who undergo PCI after a STEMI if they have pre-existing DM. What is unclear from this study is why this would be so. Further investigation would be helpful to see if this effect is real and if so, to determine what aspects of DM increase the risks of mortality in this group of patients. , ASSOCIATION OF MILD TO MODERATE KIDNEY DYSFUNCTION WITH CORONARY ARTERY CALCIFICATION IN PATIENTS WITH SUSPECTED CORONARY ARTERY DISEASE. Cao X, Yan L, Li D, et al. Cardiology 2011;120:211–6. Several studies have demonstrated that patients with chronic kidney disease have an increased risk of mortality from coronary artery disease (CAD), but the mechanism of this association is unclear. This study sought to determine whether estimated glomerular filtration rate (eGFR) was an independent predictor of coronary artery calcification. The authors enrolled 1572 consecutive symptomatic patients with clinically suspected but unproven CAD at an academic hospital in China. Patients were excluded if they had severe kidney dysfunction (eGFR < 30 mL/min/1.73 m2), known CAD, or other coexisting heart disease. Traditional risk factors for CAD were assessed, including body mass index, blood pressure, lipid profile, hemoglobin A1c, C-reactive protein, personal history of smoking, hypertension, or diabetes, and relevant family history. All patients then underwent cardiac computed tomography and the extent of coronary artery calcification was quantified according to the