Presence Of Aortic Calcification Research Articles

Hyperhomocysteinaemia and aortic calcification are associated with fractures in patients on haemodialysis

Fractures and atherosclerosis are common in patients with renal failure; this may be due to hyperhomocysteinemia. To examine the relationships between fractures, vascular calcification and homocysteine levels in haemodialysis patients. Cross-sectional survey. We enrolled 37 men and 15 women who had been on haemodialysis for at least 1 year. We identified prevalent spine fractures by radiographs. Non-spine fractures were identified by self-report and confirmed by review of radiographs or radiology reports. We classified the presence and severity of lumbar aortic calcifications with lateral lumbar radiographs. We measured serum homocysteine in all subjects within 30 days of study entry. After adjusting for age and weight, increased levels of homocysteine were associated with an increased risk fracture (OR per mmol/l increase in homocysteine 1.6, 95%CI 1.2-2.0), as was the presence of aortic calcification (OR 1.6, 95%CI 1.2-2.1). Homocysteine and lumbar aortic calcification were highly correlated (r = 0.86). Hyperhomocysteinaemia may explain the relationship between fractures and atherosclerosis in patients with renal failure.

French women, fractures and aortic calcifications

Bone loss has been suggested as a possible marker for an excess risk of cardiovascular (CV) death or stroke [1, 2]. However, previously published studies did not fully characterize this association, which remains controversial. These controversies stem from small sample sizes, confounding by age or the limitations of bone mineral density (BMD) to evaluate the severity of the bone loss. Further, this question was primarily addressed within populations with a high prevalence of risk factors for CV diseases, such as in the USA [3], in which an independent association between osteoporosis and vascular calcification is potentially more challenging to uncover. Moreover, the association between the occurrence and distribution of fractures and vascular calcification remains to be fully documented. Finally, whilst osteoprotegerin has been suggested as a possible mechanistic link between osteoporosis and vascular calcification [4], there is limited data addressing its potential role in clinical studies addressing this issue. This study was undertaken to address these gaps in knowledge within a large cohort of French women, amongst whom the prevalence of atherosclerosis can be expected to be lower based on epidemiological studies [3]. Within the same population, we evaluated simultaneously abdominal aortic calcifications (an established indicator of CV diseases), BMD, fractures and osteoprotegerin levels. We tested the hypothesis that bone loss or fractures were associated with the presence of aortic calcifications. Between January 2000 and May 2004, all consecutive postmenopausal women evaluated during one office visit for osteoporosis were included in the study. The data collected included a comprehensive history of previous fractures, lifestyle habits (smoking habits, daily consumption of calcium), CV risk factors (diabetes mellitus, hypertension or hypercholesterolaemia) and medical therapy (hormonal replacement therapy, bisphosphonates, raloxifene, calcium, vitamin D). All patients underwent a detailed medical examination, conducted at least 6 months after fractures. Standardized measurements of the BMD were performed using dual energy X-ray absorptiometry (DEXA) with a DPX-MD + scanner (Lunar Company, Lambesc, France). BMD was analysed at the femoral site, because of known pitfalls with the measure of lumbar BMD in the presence of aortic calcifications. The presence or absence of abdominal aortic calcification was assessed by one single reader from lateral lumbar spine radiographs. Osteoprotegerin was measured with enzymelinked immunosorbent assay (ELISA) kits (Nordic Bioscience, 2730 Herlev, Denmark) in 79 randomly selected patients. Differences between groups were tested with chi-square tests for categorical variables and t-tests or rank sum tests for continuous variables. Logistic regression was used to examine the association between abdominal aortic calcifications and fractures or low BMD. A total of 327 consecutive women (mean age 64 years) were enrolled. Amongst them, 59% had a history of fractures (wrist Journal of Internal Medicine 2005; 257: 117–119

Cardiovascular morbidity and endothelial dysfunction in chronic haemodialysis patients: is homocyst(e)ine the missing link?

Haemodialysis patients exhibit an excessive burden of atherothrombotic disease, which is not explained adequately by traditional risk factors. Hyperhomocyst(e)inaemia, a consistent finding in uraemic patients, is now widely recognized as an independent risk factor for vascular disease. The aim of this study was to examine the hypothesis that hyperhomocyst(e)inaemia is associated with cardiovascular complications in dialysed patients. In a cohort of 63 stable chronic haemodialysis patients, we examined the causal relationship between hyperhomocyst(e)inaemia and vascular endothelial and haemostatic function. All their markers were determined before and after an 8-week course of a 10 mg per day oral folate supplementation, a manoeuvre known to decrease hyperhomocyst(e)inaemia in uraemic patients. History of at least one cardiovascular atherothrombotic event was present in 47.6% of the haemodialysed patients, and radiographic evidence of vascular calcifications in 70%. Hyperhomocyst(e)inaemia was found in all patients, averaging 3.5-fold the upper limit of normal values (P<0.001), despite the lack of clinical and biological evidence of malnutrition. Fibrinogen, von Willebrand factor and plasminogen activator inhibitor type 1, but not endothelin 1, were significantly higher in haemodialysis patients than in controls. After adjustment for all variables, past history of cardiovascular events was independently associated with higher levels of homocyst(e)inaemia only (odds ratio (OR) 1.06; 95% confidence interval (CI) 1.01-1.12; P<0.026). The presence of aortic calcifications was independently and significantly associated with age (OR 1.37; 95% CI 1.07-1.75; P<0.025), homocyst(e)inaemia (OR 1.14; 95% CI 1.02-1.27; P<0.05) and fibrinogen concentration only (OR 9.74; 95% CI 1.25-75.2; P<0.05). None of the endothelial haemostatic factors was, however, related to homocyst(e)ine levels. Mid-term folate supplementation decreased plasma homocyst(e)ine levels significantly without achieving normal values. No significant change of endothelial-haemostatic markers was observed, however, despite the drop in plasma homocyst(e)ine. Hyperhomocyst(e)inaemia is associated with increased cardiovascular risk in haemodialysis patients. Folate supplementation was partially effective in lowering hyperhomocyst(e)inaemia, but its usefulness in terms of reduction in cardiovascular morbidity and mortality remains to be determined in prospective trials.

Nonembolic predictors of stroke risk in coronary artery bypass patients.

The aim of this study was to identify and stratify the most important nonembolic risk factors for stroke after coronary bypass grafting. From June 1994 to June 1997 a series of 1532 patients (pts) underwent isolated myocardial revascularization on cardiopulmonary bypass (CPB). A retrospective chart review selected 1417 pts in whom the presence of aortic calcification or left ventricular mural thrombi was not detectable by echocardiogram, angiogram, and intraoperative records. Univariate and multivariate analyses were conducted to identify nonembolic variables independently correlated to postoperative stroke. A predictive model of stroke probability was then constructed by means of a mathematic method with the variables selected from logistic regression analyses. The global incidence of stroke was 1.8%. Univariate analysis revealed that, among 29 preoperative and operative variables, age, vasculopathy, emergency operation, previous cerebrovascular accident (CVA), CPB, and aortic cross-clamping times were factors strongly associated with postoperative stroke (p < 0.01). A first logistic regression analysis (LRA) selected as independent predicting variables (p < 0.05) age [odds ratio (OR) 1.07/year], vasculopathy (OR 4), previous CVA (OR 7.2), CPB time (OR 1/year), and emergency operation (OR 4.2). In a second stepwise LRA, age and CPB time were subdivided into cohorts as follows: age </= 65 years, > 65 but < 75 years, >/= 75 years; CPB time </= 120 minutes, > 120 but < 180 minutes, >/= 180 minutes. Both age >/= 75 years (p = 0.024; OR 3.3) and CPB time >/= 180 minutes (p = 0.002; OR 4.2), were found to be predictors of postoperative neurologic damage. Finally, a probability table of stroke risk was obtained with the logistic regression coefficients. A lower stroke probability (0.7%) was calculated in the absence of risk variables and a higher one in the presence of all of them (83.3%). Between these extremes, a total of 158 combinations of stroke probabilities were obtained. We concluded that previous CVA, vasculopathy, emergency operation, and age > 75 years are variously associated with a high risk of nonembolic stroke after myocardial revascularization. A duration of CPB longer than 3 hours strongly increases the probability of neurologic damage in the presence of the aforementioned variables.

A study of bone mineral density versus age in Omani women and a comparison with normal British women

Dual photon absorptiometry (DPA) of the lumbar spine (2nd, 3rd and 4th lumbar vertebrae) was carried out using a Norland 2600 bone densitometer on 194 Omani women (OW). The exclusion criteria were (1) any medical treatment known to affect calcium metabolism or bone mass, (2) osteomalacia or secondary osteoporosis, (3) the presence of osteophytes or compression fractures of the lumbar vertebrae and (4) the presence of aortic calcifications. The bone mineral density (BMD) results showed a peak value occurring in the 30-35 year old age range (mean 1.1 g cm-2, standard deviation 0.1). The data were compared with a group of 165 normal British women (BW) with a similar age distribution whose peak BMD (obtained with dual X-ray absorptiometry) occurred in the 40-45 year old age range. The two groups were compared in each 10 year age range and the BMD of the OW group was found to be significantly lower in the 40-49 year old age range (P < 0.01) as well as the 50-59 and 60-69 year old age ranges (P < 0.001).

Protruding aortic atheromas predict stroke in elderly patients undergoing cardiopulmonary bypass: Experience with intraoperative transesophageal echocardiography

Protruding atheromas of the aortic arch identified by transesophageal echocardiography have been implicated as a cause of stroke in elderly patients. One hundred thirty patients ≥65 years of age were studied with intraoperative transesophageal echocardiography to detect aortic arch protruding atheromas and determine if these patients were at higher risk for perioperative stroke. Protruding atheromas were identified in 23 (18%) of 130 patients. In 19 (83%) of these 23 patients, palpation of the aortic arch at operation did not identify significant abnormalities. Five patients (4%) had perioperative stroke.Logistic regression identified aortic arch atheroma as the only historical or procedural variable that was predictive of stroke (odds ratio 5.8, 95% confidence interval 1.2 to 27.9, p < 0.03). A history of peripheral or cerebrovascular disease, presence of aortic calcification, cardiac risk factors, age and duration of cardiopulmonary bypass did not predict stroke. In contrast, patients with protruding atheromas with mobile components were at highest risk. There were 3 (25%) of 12 patients with a mobile atheroma who had a stroke versus 2 (2%) of 118 patients without a mobile atheroma (chi-square = 10.3, p = 0.001).Displacement and detachment of the frail, protruding atherosclerotic material by aortic arch cannulation or by the high pressure jet emanating from the cannula tip may play an important role in the creation of embolization and stroke.

Ten-year experience with mitral valve replacement in the elderly

Limited data are available on mitral valve replacement in the elderly patient. Therefore we report our 10-year experience including predictors of perioperative mortality and subsequent long-term cardiac mortality in elderly patients with mitral valve replacement compared to younger patients. Of the 126 consecutive patients with mitral valve replacement, 26 were older (77 ± 4, group 1) and 100 were younger (62 ± 9, group 2) than 70 years. Bioprostheses were used more frequently in patients in group 1 (65% vs 7%, p < 0.0001). Of the 21 clinical, ECG, hemodynamic, and angiographic variables studied, patients in group 1 had higher pulmonary artery systolic pressure (57 ± 15 vs 48 ± 19, p < 0.05), fascicular block on ECGs (70% vs 33%, p < 0.005), and greater pump time on cardiopulmonary bypass (160 ± 75 vs 120 ± 50 minutes, p < 0.025). A trend toward a higher perioperative mortality rate was also seen in group 1 (27% vs 12%, p = 0.058). Predictors of perioperative mortality by multivariate analysis were the presence of aortic calcification and prolonged pump time on cardiopulmonary bypass in group 1 and coronary artery disease, female sex, elevated mean pulmonary artery pressure, and postoperative complete atrioventricular block in group 2. During a mean 4-year follow-up period, cardiac mortality and total mortality rates were 42% and 54%, respectively, for group 1 compared to 24% and 35%, respectively, for group 2. Predictors of cardiac mortality by multivariate analysis were aortic calcification, pacemaker implantation, elevated mean pulmonary artery pressure, decreased left ventricular ejection fraction, and smaller prosthetic valve size in group 1 and female sex, coronary artery disease, perioperative atrioventricular block, age, and elevated mean pulmonary artery pressure in group 2. Thus elderly patients with mitral valve replacement have higher perioperative mortality and subsequent cardiac mortality than younger patients. Further studies comparing mitral valve replacement with valve repair and valvuloplasty seem indicated.

Arteriosclerosis and Antihypertensive Response to Calcium Antagonists in End-Stage Renal Failure

The relationship between the presence of arterial calcinosis and the antihypertensive response to calcium blockers was studied in 40 hypertensive patients with end-stage renal failure (ESRF) on chronic hemodialysis, before and during 16 weeks after administration of nitrendipine in monotherapy. In a double-blind, placebo-controlled, randomized study, nitrendipine reduced systolic blood pressure regardless of the presence or absence of arterial calcifications. The antihypertensive effect was significantly more pronounced in subjects with aortic calcium deposits in comparison with patients without clinical signs of arteriosclerosis (p less than 0.01). The diastolic blood pressure was significantly reduced only in patients with aortic calcifications, and remained unchanged in subjects with noncalcified aorta. The aortic pulse wave velocity decreased significantly in patients with aortic calcifications (p less than 0.001), but remained unaffected in patients with noncalcified vessels. Multivariate regression analysis showed that the antihypertensive action of nitrendipine was correlated to the presence of aortic calcium deposits independent of age or baseline blood pressure levels. The results of the present study indicate that an overt arteriosclerosis as demonstrated by the presence of aortic calcifications on abdominal radiographs is a good indication for the use of dihydropyridines in patients with ESRF.

Arteriosclerosis and Antihypertensive Response to Calcium Antagonists in End-Stage Renal Failure

The relationship between the presence of arterial calcinosis and the antihypertensive response to calcium blockers was studied in 40 hypertensive patients with end-stage renal failure (ESRF) on chronic hemodialysis, before and during 16 weeks after administration of nitrendipine in monotherapy. In a double-blind, placebo-controlled, randomized study, nitrendipine reduced systolic blood pressure regardless of the presence or absence of arterial calcifications. The antihypertensive elfect was significantly more pronounced in subjects with aortic calcium deposits in comparison with patients without clinical signs of arteriosclerosis (p < 0.01). The diastolic blood pressure was significantly reduced only in patients with aortic calcifications, and remained unchanged in subjects with noncalciticd aorta. The aortic pulse wave velacity decreased significantly in patients with aortic calcifications (p < 0.001). but remained unaffected in patients with noncalciticd vessels. Multivariate regression analysis showed that the antihypertensive action of nitrendipine was correlated to the presence of aortic calcium deposits independent of age or baseline blood pressure levels. The results of the present study indicate that an overt arteriosclerosis as demonstrated by the presence of aortic calcifications on abdominal radiographs is a good indication for the use of dihydropyridincs in patients with ESRF.

Detection of prefracture spinal osteoporosis using bone mineral absorptiometry.

Bone mineral measurements have been criticized for their inability to clearly distinguish fracture and "nonfracture" populations. However, this failure is not unexpected, since some individuals in the "nonfracture" group have low bone mass and are at increased risk but have not yet experienced fractures. Although standard radiographs are not sensitive indicators of vertebral demineralization, they do identify some of the "prefracture" osteoporotic subpopulation within the nonfracture group. Prospective follow-up of 536 Japanese-American women demonstrated that 14 new spine fractures occurred in the prefracture osteoporosis group, whereas none occurred in the nonosteoporotic group (p less than or equal to 0.03). However, bone mineral content (BMC) measurements using photon absorptiometry were much more accurate than radiographs as indicators of spine fracture risk. BMC values were somewhat higher in the prefracture group than in those with existing fractures, but values for both groups were significantly lower than in nonosteoporotic patients even after adjusting for age, height, and weight (p less than 0.0001). The magnitude of the difference was proportional to the trabecular bone content of the measurement site; the differences were greatest for the os calcis and lumbar spine, smaller for the distal radius, and least for the proximal radius. The prevalence of spinal osteoporosis (including both fracture and prefracture cases) was inversely proportional to BMC (p less than 0.0001). Again, the relations were strongest for the os calcis and lumbar spine. These results indicate that BMC measurements are valid indicators of osteoporosis status, particularly when osteoporosis is defined to include both patients with existing fractures and those at increased risk for fractures. However, dual-photon spine BMC was adversely influenced by the presence of aortic calcification, arthritis, and other disease processes (p less than or equal to 0.0001).