Relationship between diabetes mellitus and degree of coronary artery disease in uraemic patients investigated with coronary angiography

Prevalence of cardiovascular disease is high in diabetic patients on renal replacement therapy (RRT); therefore we examined the role of diabetes mellitus on determining the degree of coronary artery stenosis. Twenty-five patients underwent coronary angiography, 12 were awaiting kidney transplantation and the examination was performed regardless of cardiac symptoms, 13 were affected by ischaemic heart disease (IHD). Diabetic and nondiabetic status together with the other risk factors for cardiovascular disease such as age, sex, length of time on RRT, smoking and elevated phosphorus levels history, clinical diagnosis of IHD, cerebrovascular and peripheral vascular disease, mean blood pressure, cholesterol, triglycerides, calcium, phosphate, albumin, haemoglobin, haematocrit and weekly dose of erythropoietin were derived from clinical records. All investigated parameters were matched in diabetic (group 1, n=10) and nondiabetic patients (group 2, n=15) and showed no differences. Clinical evidence of IHD was detected in 80% of patients in group 1 and 46% in group 2 and the percentage of patients on the renal transplant waiting list was not statistically different in the two groups (30 vs 60%). In 60% of patients in group 1 there were 3 or more stenotic lesions equal or greater than 75% of normal reference segment in the major coronary arteries, whilst in 53% in group 2 there were no haemodynamically significant narrowings. Narrowing percentage of the coronaries in group 1 and 2 were: right coronary artery 83 +/- 30 vs 32 +/- 41 (p<0.05), left anterior descending artery 80 +/- 25 vs 44 +/- 34 (p<0.05), left circumflex artery 46 +/- 37 vs 18 +/- 29 (p=0.05) respectively. Our study confirms that IHD is a clinical feature of uraemic diabetic patients and that diabetes is the main cardiovascular risk factor for determining the degree of coronary stenosis.     

Two-dimensional echocardiography in the diagnosis of intracardiac masses: A prospective study with anatomic validation

The accuracy of two-dimensional echocardiography in the detection of intracardiac masses was verified in 334 patients who underwent cardiac catheterization in our laboratory over 21 consecutive months. A complete two-dimensional echocardiographic (2DE) examination was performed a day before catheterization. The presence or absence of a mass was verified at surgery in 77 patients who successively underwent mitral or aortic valve replacement (51), left ventricular aneurysmectomy with or without myocardial revascularization (25), and resection of atrial myxoma (2). In 32 patients 2DE revealed the presence of a mass-left or right atrial thrombi in 12, left atrial myxoma in 2, left ventricular thrombi in 16, and endocardial vegetations in 2. The other 45 patients were free of intracardiac masses on 2DE. Anatomic verification at surgery revealed the presence of an intracardiac mass in 34 patients. In 30 (true positives) of these, 2DE revealed the mass as well, and in 4 (false negatives) the presence of a mass had not been identified by 2DE. In 2 patients (false positives) the predicted mass was not found at surgery. Absence of a mass was correctly predicted by 2DE in 41 patients (true negatives). Thus 2DE detected intracardiac masses with sensitivity of 88.2% and a specificity of 95.3%. We recommend that 2DE be performed in all patients prior to hemodynamic study and/or cardiac surgery to enable safer management of patients with intracardiac masses during cardiac catheterization and/or cardiac surgery.     

Relationship between major adverse cardiac events and angiographic findings in dialysis patients

Background  

In dialysis patients, coronary angiography (CA) predicts major adverse coronary events (MACE) better than non-invasive tests. The aim of this study was to investigate in such patients the relationship between coronary atherosclerotic damage shown by angiography and MACE, during an average follow-up period of more than 5 years.     

BACE-2 is overexpressed in Down's syndrome

Brain deposition of the amyloid-beta protein (Abeta) is a frequent complication of Down's syndrome (DS) patients. Abeta peptide is generated by endoproteolytic processing of Abeta precursor protein by gamma and beta secretases. Recently a transmembrane aspartyl protease, BACE, has been identified as the beta-secretase, and its homologous BACE-2 has also been described. BACE-2 gene resides on chromosome 21 in the obligate DS region. It cleaves Abeta precursor protein at its beta site and more efficiently at a different site within Abeta. In the present study we characterized the BACE-2 gene and protein expression in the DS patients and healthy control. We analyzed, by using a nonradioactive ribonuclease protection assay, the levels of BACE-2 mRNA expression in primary skin fibroblasts. The analysis revealed a 2.6-fold increase in BACE-2 mRNA levels in the DS group compared to the levels observed in the control group. Western blot analysis revealed no difference between DS and control in BACE-2 protein levels in the intracellular compartment. In the medium conditioned by fibroblast, we revealed an evident secretion of BACE-2 protein, represented by two different molecular weights, remarkably increased in DS fibroblasts. BACE-2 overexpression was also confirmed in the DS fetal brains and human neural embryonic DS stem cells in which conditioned media BACE-2 was secreted. These data highlight the importance of the extracellular compartment where BACE-2 overexpression could play a role in plaque formation in DS patients.     

Variable expression of familial Alzheimer disease associated with presenilin 2 mutation M239I

In a family with autopsy-confirmed Alzheimer disease, the authors found a mutation in the presenilin 2 (PS2) gene (PSEN2) that predicts a methionine-to-isoleucine change at PS2 residue 239 (M239I), at which a change to valine was known in another family. Phenotypic expression of M239I was highly variable, with disease onset between age 44 and 58 years, and two nonaffected mutation carriers at age 58 and 68 years. The data showed no influence of APOE but were compatible with other possible genetic modifiers of the phenotype or penetrance of M239I.     

Direct visualization of aorto-coronary bypass grafts by two-dimensional echocardiography: A new clinical application

An attempt was made to assess noninvasively the patency of aorto-coronary bypass grafts by two-dimensional echocardiography (2-D echo) in 21 patients who underwent myocardial revascularization. Fifteen patients had one graft while the other six had two grafts. All 21 patients underwent angiography 6–18 months after operation. A day before angiography a 2-D echo was performed with the aim of visualizing the bypass grafts. In 18 patients with 23 grafts (13 with 1 graft and 5 with 2 grafts) it was possible to visualize the tract of the graft, by 2-D echo; 16 were judged patent on 2-D echo and confirmed by selective angiography, while 5 grafts were considered occluded both on 2-D echo and angiography. The other 2 grafts were considered to be occluded on 2-D echo but angiographic control displayed their patency. In 3 patients 2-D echo failed to visualize grafts that were patent angiographically. These data must be considered preliminary and need validation in a larger number of patients. However it is reasonable to conclude that 2-D echo has a reliable capacity to predict graft patency. Such an application may be of value in sequential control of patients with aorto-coronary bypass surgery, especially when combined with other clinical and/or technical data.     

Afterload reduction with nifedipine in aortic insufficiency

The acute hemodynamic effects of nifedipine were assessed In 12 patients with severe isolated aortic Insufficiency during control conditions and 30 minutes after administration of nifedipine (20 mg sublingually). Left ventricular end-diastollc pressure decreased from 19 ± 8 (mean ± standard deviation) to 9 ± 5 mm Hg (probability [p] < 0.0001), mean aortic pressure from 98 ± 12 to 80 ± 9 mm Hg (p < 0.0001), systemic vascular resistance from 1,135 ± 280 to 794 ± 176 dynes·s·cm^?5 (p < 0.0002) and rate-pressure product from 11,732 ± 1,727 to 10,022 ± 1,103 mm Hg⁺ beats/min (p < 0.01). Forward cardiac index increased by 24 percent, from 3.8 ± 1.1 to 4.4 ± 0.8 liters/min per m² (p < 0.04). Left ventricular end-diastolic volume, ejection fraction and total stroke work index did not change significantly. Regurgitant fraction, measured in five patients, changed parallel with systemic vascular resistance. Left ventricular function was maintained while both preload and afterload were decreased. Regurgitant flow was moderated and myocardial oxygen demand decreased. This hemodynamically favorable condition, due to nifedlpine, is clinically important and suggests the need for further therapeutic trials.     

A simplified technique for antegrade selective cerebral perfusion

Various methods of cerebral protection have been used during aortic arch surgery. We reviewed our experience with a modified technique for selective cerebral perfusion (SCP) administration during surgery on the thoracic aorta from October 1999. Conventionally, this technique requires an additional roller pump on the cardiopulmonary bypass (CPB) console. In order to simplify the extracorporeal circuit (ECC), the paediatric double-roller pump used for the administration of cardioplegia was utilized by adding a 'Y-connection' on the blood line of the cardioplegia circuit, upstream of the cardioplegia reservoir, to provide SCP blood flow. SCP administration with a Y-connection is both easy and fast to set up on the ECC circuit and does not create additional difficulties to the surgeon. It simplifies SCP delivery by allowing the perfusionist to use a standard ECC system set-up.