Effects of Acute Acid Loading on the Risk of Calcium Phosphate and Calcium Oxalate Crystallization in Urine

The aim of this study was to examine the risk of calcium phosphate and calcium oxalate crystallization during acute acid loading under controlled conditions. The effects of acute acid loading on rates of renal excretion of calcium, magnesium, phosphate, citrate, oxalate and urine pH were studied in healthy subjects. The risk of calcium phosphate and calcium oxalate crystallization were evaluated by estimates of the ion activity products of calcium phosphate [AP(CaP)-index] and calcium oxalate [AP(CaOx)-index] according to Tiselius. In addition, the risk of brushite [AP(Bru)-index] crystallization was estimated. An acute acid load administered as ammonium chloride (NH4Cl) produced increased urinary excretion of calcium, phosphate and oxalate, decreased urinary excretion of citrate, and a decrease in urine pH. Consequently, calcium-citrate-ratio in urine increased markedly in response to acid loading. AP(CaP)-index decreased markedly due to a fall in urine pH. AP(Bru)-index decreased slightly and remained low throughout the study. AP(CaOx)-index increased significantly, and acid loading is suggested as a risk factor for calcium oxalate stone formation

Revascularization in multivessel disease: Comparison between two-year outcomes of coronary bypass surgery and stenting

AbstractObjective: The recent appreciation that stenting has improved the short- and long-term outcomes of patients treated with coronary angioplasty has made it imperative to reconsider the comparison between surgery and percutaneous interventions in patients with multivessel disease. Methods: One thousand two hundred five patients were randomly assigned to undergo bypass surgery or angioplasty with stent implantation when there was consensus between the cardiac surgeon and interventional cardiologist as to equivalent treatability. The primary clinical end point was freedom from major adverse cardiac and cerebrovascular events at 1 year. Major adverse cardiac and cerebrovascular events at 2 years constituted a secondary end point. Results: At 2 years, 89.6% of the surgical group and 89.2% of the stent group were free from death, stroke, and myocardial infarction (log-rank test P =.65). Among patients who survived without stroke or myocardial infarction, 19.7% in the stent group underwent a second revascularization, as compared with 4.8% in the surgical group (P <.001). At 2 years, 84.8% of the surgical group and 69.5% of the stent group were event-free survivors (log-rank test P <.001), and 87.2% in the surgical cohort and 79.6 % in the stent group were angina-free survivors (P =.001). In the diabetes subgroup, 82.3% of the surgical group and 56.3% of the stent group were free from any events after 2 years (log-rank test P <.001). Conclusion: The difference in outcome between surgery and stenting observed at 1 year in patients with multivessel disease remained essentially unchanged at 2 years. Stenting was associated with a greater need for repeat revascularization. In view of the relatively greater difference in outcome in patients with diabetes, surgery clearly seems to be the preferable form of treatment for these patients.J Thorac Cardiovasc Surg 2003;125:809-2