Spontaneous Dissection of Right Coronary Artery Manifested with Acute Myocardial Infarction

Spontaneous coronary artery dissection is a rare cause of acute ischemic coronary events and sudden cardiac death. It usually occurs in young women without traditional risk factors for coronary artery disease during pregnancy or postpartum period. However, it has also been reported in patients with atherosclerotic coronary disease. We present a case of spontaneous right coronary artery dissection in a 48-year male with recent myocardial infarction and previous percutaneous coronary intervention

Bone-specific alkaline phosphatase concentrations are less variable than those of parathyroid hormone in stable hemodialysis patients

Abnormalities of bone mineral metabolism and vascular calcification are prevalent in patients with kidney failure. Clinical management is based on biochemical targets, in particular parathyroid hormone (PTH) concentrations, but this has many limitations including high biological variation. A possible alternative is bone-specific alkaline phosphatase (ALP); therefore, we evaluated the biological variation of this marker in patients undergoing hemodialysis. Bone ALP was measured in non-fasting serum samples taken twice a week over a 6-week period in 22 stable hemodialysis patients and 12 healthy volunteers. The within-individual coefficients of variance were calculated and used to derive the critical difference required to be certain that an observed change was significant. The coefficient of variance for bone ALP was significantly higher in hemodialysis patients compared to healthy individuals. Seven samples were required to estimate the homeostatic set point of bone ALP, within 10%, in a hemodialysis patient. The concentration of serial bone ALP measurements would need to change by 36% between any two measurements before it can be considered a significant change. Since the biological variation of bone ALP is less than half that reported for PTH, our study provides further support for the use of bone ALP as an alternative marker of bone mineral metabolism in the setting of chronic kidney disease–mineral and bone disorder

Patients with autosomal dominant polycystic kidney disease have elevated fibroblast growth factor 23 levels and a renal leak of phosphate

Fibroblast growth factor 23 (FGF23) and parathyroid hormone blood levels rise following progressive loss of renal function. Here we measured parameters of phosphate metabolism in 100 patients with autosomal dominant polycystic kidney disease (ADPKD) in stage 1 or 2 of chronic kidney disease, 20 patients with non-diabetic chronic kidney disease, and 26 with type 2 diabetes. Twenty healthy volunteers served as controls. The mean levels of FGF23 were significantly (4-fold) higher in ADPKD compared to non-diabetic and diabetic patients, and healthy volunteers. Mean serum phosphate levels were significantly lower in ADPKD patients compared to non-diabetic and diabetic patients, and the healthy volunteers. The prevalence of hypophosphatemia was 38, 25, 27, and 5% in ADPKD, non-diabetic and diabetic patients, and healthy volunteers, respectively. The tubular maximum of phosphate reabsorption per glomerular filtration rate was lowest in ADPKD patients with a significantly high positive correlation with serum phosphate levels. Estimated glomerular filtration rates were approximately 100 ml/min per 1.73 m(2) in all groups and parathyroid hormone and vitamin D metabolite levels were in the normal range. Thus, FGF23 was substantially elevated in ADPKD patients compared to other CKD patients matched for glomerular filtration rate, and was associated with increased renal phosphate excretion. The mechanism for this anomaly will require further study

Validation of a new contrast material protocol adapted to body surface area for optimized low-dose CT coronary angiography with prospective ECG-triggering

In patients with large total blood volume contrast material (CM) dilution decreases coronary attenuation in CT coronary angiography (CTCA). As increased blood volume is well paralleled by body surface area (BSA) we assessed a BSA-adapted CM protocol to compensate for dilution effects. Low-dose CTCA with prospective ECG-triggering was performed in 80 patients with a BSA-adapted CM bolus ranging 40-105 ml and injection rate ranging 3.5-5.0 ml/s for a BSA of or=2.5 m(2). Eighty control patients matched for BSA who had previously undergone routine CTCA with a fixed CM protocol of 80 ml at 5 ml/s served as reference group. The average vessel attenuation from the proximal right (RCA) and the left main coronary artery (LMA) was assessed. Correlation of BSA with vessel attenuation was assessed in both groups. BSA-matching of all patients was successful (BSA-adapted group 1.98 +/- 0.15 m(2), range 1.66-2.39 m(2) versus reference group 1.98 +/- 0.17 m(2), range 1.59-2.38 m(2); P = 0.74). Mean CM bolus was significantly smaller in the BSA-adapted versus the reference group (70.9 +/- 14.1 vs. 80.0 +/- 0 ml, P < 0.001). There was no correlation in the BSA-adapted group (r = -0.07, P = 0.53, SEE = 0.15), while coronary attenuation was inversely related to BSA in the reference group (r = -0.59, P < 0.001, SEE = 0.14). We have successfully validated a BSA-adapted contrast material protocol which results in a comparable coronary contrast enhancement independent of individual BSA. This was achieved despite a significant reduction in the overall contrast material amount