Wear Evaluation of Prosthetic Materials Opposing Themselves.

The purpose of the present in vitro study was to compare the two-body wear resistance of a type 3 gold alloy (Aurocast8), two lithium disilicate glass ceramics (IPS e.max CAD and IPS e.max Press), a heat-pressed feldspathic porcelain (Cerabien ZR Press), an yttria-stabilized tetragonal zirconia polycrystal ceramic (Katana Zirconia ML), and three heat-cured composite resins (Ceram.X Universal, Enamel Plus Function, and Enamel Plus HRi) opposing antagonistic cusps made out of the same restorative materials. Ten 6-mm-thick samples and 10 cusp-shaped abraders were manufactured with each test material (n=10) according to standard laboratory procedures. All sample/antagonist pairs made out of the same material were subjected to a two-body wear test in a dual-axis chewing simulator for up to 120,000 loading cycles. The total vertical wear (mm) and the total volumetric loss (mm3) for each sample/antagonist pair were calculated. Data were statistically analyzed using one-way analysis of variance tests. The total vertical wear for the gold alloy was not significantly different compared to Ceram.X Universal, Enamel Plus Function, IPS e.max CAD, and Cerabien ZR Press. Significantly increased wear values were observed for Enamel Plus HRi and IPS e.max Press. The lowest values for total vertical wear and volumetric loss were recorded on the monolithic zirconia.

Wear properties of a novel resin composite compared to human enamel and other restorative materials.

The purpose of this in vitro study was to compare the two-body wear resistance of human enamel, a pressable glass-ceramic (Imagine PressX), a type 3 gold alloy (Aurocast8), three resins composites currently available on the market (Enamel plus HRi, Filtek Supreme XTE, Ceram.X duo), and one recently introduced resin composite (Enamel plus HRi-Function). Resin composites were tested after simple light curing and after a further heat polymerization cycle. Ten cylindrical specimens (7 mm in diameter) were manufactured with each dental material according to standard laboratory procedures. Ten flat enamel specimens were obtained from freshly extracted human molars and included in the control group. All samples were subjected to a two-body wear test in a dual-axis chewing simulator over up to 120,000 loading cycles, against yttria stabilized tetragonal zirconia polycrystal cusps. Wear resistance was analyzed by measuring the vertical substance loss (mm) and the volume loss (mm(3)). Antagonist wear (mm) was also recorded. Data were statistically analyzed using one-way analysis of variance (ANOVA) (wear depth and volume loss) and Kruskal-Wallis one-way ANOVA on ranks (antagonist wear). Heat-cured HRi function and Aurocast8 showed similar mean values for wear depth and volumetric loss, and their results did not statistically differ in comparison with the human enamel.

Heart imaging: the accuracy of the 64-MSCT in the detection of coronary artery disease.

At present, coronary angiography represents the gold standard technique for the diagnosis of coronary artery disease. Our aim is to compare the conventional coronary angiography to the coronary 64-multislice spiral computed tomography (64-MSCT), a new and non-invasive cardiac imaging technique. The last generation of MSCT scanners show a better imaging quality, due to a greater spatial and temporal resolution. Four expert observers (two cardiologists and two radiologists) have compared the angiographic data with the accuracy of the 64-MSCT in the detection and evaluation of coronary vessels stenoses. From the data obtained, the sensibility, the specificity and the accuracy of the coronary 64-MSCT have been defined. We have enrolled 75 patients (57 male, 18 female, mean age 61.83 +/- 10.38; range 30-80 years) with known or suspected coronary artery disease. The above population has been divided into 3 groups: Group A (Gr. A) with 40 patients (mean age 60.7 +/- 12.5) affected by both non-significant and significant coronary artery disease; Group B (Gr. B) with 25 patients (mean age 60.3 +/- 14.6) who underwent to percutaneous coronary intervention (PCI); Group C (Gr. C) with 10 patients (mean age 54.20 +/- 13.7) without any coronary angiographic stenoses. All the patients underwent non-invasive exams, conventional coronary angiography and coronary 64-MSCT. The comparison of the data obtained has been carried out according to a per group analysis, per patient analysis and per segment analysis. Moreover, the accuracy of the 64-MSCT has been defined for the detection of >75%, 50-75% and <50% coronary stenoses. Coronary angiography has identified significant coronary artery disease in 75% of the patients in the Gr. A and in 73% of the patients in the Gr. B. No coronary stenoses have been detected in Gr. C. According to a per segment analysis, in Gr. A, 36% of the segments analysed have shown a coronary stenosis (37% stenoses >75%, 32% stenoses 50-75% and 31% stenoses <50%). In Gr. B, 32% of the segments have shown a coronary stenosis (33% stenoses >75%, 29% stenoses 50-75% and 38% stenoses <50%). In-stent disease has been shown in only 4 of the 29 coronary stents identified. In Gr. A, coronary 64-MSCT has confirmed the angiographic results in the 93% of cases (sensibility 93%, specificity 100%, positive predictive value 100% and negative predictive value 83%) while, in Gr. B, this confirm has been obtained only in 64% of cases (sensibility 64%, specificity 100%, positive predictive value 100% and negative predictive value 50%). In Gr. C, we have observed a complete agreement between angiographic and CT data (sensibility, specificity, positive predictive value and negative predictive value 100%). According to a per segment analysis, the angiographic results have been confirmed in 98% of cases in Gr. A (sensibility 98%, specificity 94%, positive predictive value 90% and negative predictive value 94%) but only in 55% of cases in Gr. B (sensibility 55%, specificity 90%, positive predictive value 71% and negative predictive value 81%). Moreover, only 1 of the 4 in-stent restenoses has been detected (sensibility 25%, specificity 100%, positive predictive value 100% and negative predictive value 77%). Coronary angiography has detected a greater number of coronary stenoses than the 64-MSCT. 64-MSCT has demonstrated better accuracy in the study of coronary vessels wider than 2 mm, while its accuracy is lower for smaller vessels (diameter < 2.5 mm) and for the identification of in-stent restenosis, because there is a reduced image quality for these vessels and therefore a lower accuracy in the coronary stenosis detection. Nevertheless, 64-MSCT shows high accuracy and it can be considered a comparative but not a substitutive exam of the coronary angiography. Several technical limitations of the 64-MSCT are responsible of its lower accuracy versus the conventional coronary angiography, but solving these technical problems could give us a new non-invasive imaging technique for the study of coronary stents.

A new completely flexible ring for mitral valve annuloplasty: the "Rama-Valvuloplasty-Ring". Five-year Pitié Salpétrière experience.

The aim of this study was to analyze the effects about the use of a new completely flexible ring for mitral valve anuloplasty, the "Rama-Valvuloplasty-ring", in 182 patients operated on in the Pitié-Salpétrière Hospital, Paris, France for mitral valve regurgitation (MVR). From January 1998 to December 2003, 182 patients with mitral regurgitation (MR) underwent mitral reconstructive surgery at our institution with the "Rama-Valvuloplasty-Ring". This group was made up of 117 men (64.3%) and 65 women (35.7%). The age ranged from 19 to 87 years (mean 62.51 +/- 8.2 years). The patients surviving the operation were the subject of a prospective follow-up. In the preoperative stage sinus rhythm was found in 71.97% (131) of patients and atrial fibrillation in the remaining 28.03% (51) of patients. The mean NYHA FC was 2.9 +/- 1.7 and subdivided as follows: 65 patients in FC I-II (35.72%), 104 patients in FC III (57.14%) and 13 patients in FC IV (7.14%). Most of the patients have shown, in the preoperative echocardiogram, grade II M.R. (46.15% N. 84) and grade III M.R. (29.12%, N.53); 24.72% of the patients (N. 45) had grade IV M.R. The mean E.F. was 42.8 +/- 9.7%. Left ventricular end diastolic diameter (LVEDD) was 57.7 +/- 9.7 mm. The causes of mitral valve insufficiency were degenerative disease in 141 patients (77.47%), post-ischemic disease in 21 patients (11.53%), rheumatic valvular disease in 11 patients (6.05%) and infectious endocarditis in 9 patients (4.95%). All the patients were operated using the Rama-Valvuloplasty-Ring. Ring sizes most commonly used were 30 mm and 32 mm, respectively in 92 patients (50.55%) and 41 patients (22.54%), followed by 28 mm (43 patients, 23.62%), 34 mm (5 patients, 2.74%), 36 mm (1 patient, 0.55%). The surgical tecnique was valve quadrangular resection in 103 patients (56.60%), triangular resection in 57 patients (31.32%) and no valve resection in 22 patients (12.08%). Among the above, 89 patients (48.90%) underwent an associated intervention as follows: 44 patients (24.18%) underwent coronary revascularization: 18 patients (9.89%) with single by-pass surgery, 21 patients (11.54%) with double by-pass, 5 patients with triple by-pass (2.75%); 42 patients (23.07) underwent aortic valve replacement (AVR); 3 patients (1.65%) underwent aortic repair. Early postoperative mortality was 2.19% (4 of 182 patients). Early postoperative echocardiographic control showed MR grade 0 in 142 patients (79.78%) and grade I in 36 (20.22%) with mean grade 0.4 +/- 0.12; no patients with grade III or IV. Therefore, there was no mitral annuloplasty failure requiring valve replacement (MVR). During the follow-up there were 12 late deaths (12 of 178 patients, 6.74%). Only one death was valve-related (thrombosis) whereas the other 11 ones were non cardiac-related deaths (subdural frontal haematoma, septic shock). Postoperative transthoracic echocardiogram data were available in 166 patients at 5 years: the presence of postoperative MR was evaluated and severity was graded as mild in 33 patients (19.88%), moderate in 18 patients (10.84%), severe in 3 (1.81%) patients. There was no MR in the other 112 patients (67.47%); LVEDD was 49.4 +/- 6.5 mm; EF was 51.8 +/- 4.3%. The mean NYHA FC was 0.8 +/- 0.4. Only one patient was reoperated on during the follow-up because of mitral annuloplasty failure with MVR. In conclusion, mid-term 5-years follow up is good for patients operated on with the new completely flexible Rama-Valvuloplasty-Ring for mitral annuloplasty. This study has also verified the advantage about the Rama-Valvuloplasty-Ring use in the preservation of native valve apparatus.

The endovascular treatment of traumatic isthmic aortic rupture: three years follow-up.

The isthmic aortic rupture represents the main cause of death in car crash accidents, because of closed chest trauma. Early medical and surgical care and endovascular prosthesis treatment with semi-invasive method can improve short and mid term survival. Nine patients with traumatic isthmic aortic rupture underwent endoprosthesis aortic implantation. All the patients were male, mean age 42.48 +/- 17.66 years. Operations included 5 acute cases and 4 chronic cases (chance diagnosis). In all cases the diagnosis was performed by tomodensitometric exam. Cloth prostheses were used (self-expansible Goretex- or Dacron-stent). Three years after the endoprosthesis implantation, we obtained the complete thrombosis of the false aortic lumen in all patients, both acute and chronic, as well as the levelling of the false aneurysms without complications of any kind.

Morphological and functional changes of cardiovascular system in postmenopausal women.

BACKGROUND: The incidence of cardiovascular events in reproductive age women is 3 times lower than in men, whereas this ratio noticeably changes on menopausal beginning. Postmenopausal women are more exposed to the effects of risk factors, which are present in a noticeably different entity in physiological or surgical menopause; and in the latter whether on substitutive hormonal treatment or not. METHODS: This study, carried out in Rome and Latina, has involved 743 postmenopausal women, of whom 545 with physiological menopause and 198 with iatrogenic menopause. RESULTS: The average blood pressure value as well as the incidence of hypertension, hypercholesterolemia, diabetes mellitus, obesity and smoking have a significantly different trend in physiological versus iatrogenic postmenopausal women; and in the latter whether on substitutive hormonal treatment or not. CONCLUSIONS: Studying life-style and evaluating risk factors in postmenopausal women, and giving an up-to-date view about the prevalence oh health conditions at risk, will allow us to promote both primary and secondary prevention actions.

Thrombus formation in the left atrial appendage in the course of atrial fibrillation.

BACKGROUND: Thromboembolism in patients with nonvalvular atrial fibrillation is secondary to emboli arising from atrial cavities, particularly left atrial appendage. Stroke Prevention Atrial Fibrillation (SPAF) III study showed washing flow, left appendage ejection fraction, natural echocontrast, and left appendage volume and morphology, as risk parameters of thromboembolism. METHODS: The authors examined 69 patients by transesophageal echocardiography, subdividing them into 3 groups: 26 patients in sinus rhythm in Group A (Gr.A), 22 patients in atrial fibrillation without thrombi in the left atrial appendage in Group B (Gr.B), 21 patients with tromboembolism and with thrombus in the left atrial appendage (Gr.C). RESULTS: Atrial volume in sinus rhythm (SR) patients (41.9 +/- 23.4 cm3) was lower than the one in Gr.B (86.2 +/- 47.9 cm3, p < 0.001) and Gr.C (78.6 +/- 28.5 cm3, p < 0.01), whereas no difference was found between Gr.B and Gr.C (86.2 vs. 78.6 cm3; p > 0.05). No difference was found between Gr.A and Gr.B left atrial appendage fraction (31.8% versus 29.1%, p > 0.05), whereas it was found related to Gr.C (31.8% versus 15.4% p < 0.01). Flow velocity within left atrial appendage was significantly higher in Gr.A in relation to the other two groups (p < 0.001); flow velocity in Gr.B was lower than in Gr.A but higher than in Gr.C and in all cases such differences were statistically significant (p < 0.001). Gr.A flow duration was approximately twice as much compared to the one in Gr.B (616.8 +/- 94.1 msec vs. 483.3 +/- 172.6 msec, p < 0.01), whereas it was approximately four times higher compared to the one in Gr.C (616.8 +/- 94.1 msec vs. 165.7 +/- 53.7 msec; p < 0.001). Such duration, if related to the corresponding cardiac cycle, indicates the percentage of time during which blood flows through a cycle within the left atrial appendage; this value is about 85% of cardiac cycle in Gr.A, while it is 65% in Gr.B (p < 0.01) and about 21% in Gr.C (p < 0.001). CONCLUSIONS: Such results add a new parameter to the ones suggested in the SPAF III study for the evaluation of TE risk, that is flow duration measurement within the left atrial appendage, and its ratio to the cardiac cycle. The availability to measure this parameter, by recording the transesophageal pulse wave sample volume positioned in the atrial appendage, makes the evaluation of TE risk more reliable.

Diastolic mitral regurgitation: a borderline case in cardiovascular physiology.

BACKGROUND: Mitral regurgitation during diastole in 5 subjects, of whom 4 affected by cardiovascular disease and 1 healthy competitive athlete, was the aim of this work. The 4 patients are respectively affected by: 1st case: arterial hypertension, dyslipidemia and III degree AV block in NYHA class II heart failure (HF); 2nd case: NYHA III HF, prosthetic biologic aortic valve dysfunction; 3th case: NYHA III HF, ischemic dilated cardiomyopathy; 4th case: ischemic dilated cardiomyopathy waiting for heart transplantation. METHODS AND RESULTS: The above 4 patients showed, on transthoracic echocardiogram, mitral diastolic regurgitation. The authors deem as caused, in agreement with the literature, both by an atrio-ventricular pressure gradient inversion during long-lasting diastoles (III degree atrioventricular block, blocked atrial systole, aortic valve regurgitation), and by an inadequate ventricular remodelling/distensibility. The 5th case deals with a healthy highly trained competitive athlete who, at the fitness checkup, showed mitral diastolic regurgitation. The study was also extended to two healthy groups of subjects, in order to rule out mitral regurgitation during the diastolic interval of the cardiac cycle. CONCLUSIONS: Such finding, after an accurate and critical analysis, led the authors to assume it may deal with a borderline physiological condition.

[Wall elasticity of the ascending aorta in ischemic heart disease]. / Elasticità parietale dell'aorta ascendente nella cardiopatia ischemica.

M-mode echocardiography was used to examine in male subjects the physical properties of the ascending aorta, 3 cm above the valvular plane. Subjects were divided into three groups based on age, lifestyle and presence or absence of vascular disease: Group A (10 recruited military young men, age 20.87 +/- 0.834 years) in good health; Group B (14 senior competitive athletes, age 49.92 +/- 8.17 years); Group C (10 patients with effort-angina, age 53.1 +/- 11.18 years). We observed that: the inner diastolic diameter of the ascending aorta was different between Group A and B (p < 0.001) and between Group A and C (p < 0.001), and it increased with aging (r = 0.7) whereas no relationship to body surface was seen (r = 0.3); the elasticity-stiffness parameters (aortic wall distensibility, aortic wall stress, wall stiffness index, wall elasticity index and modulus) of major vessels in senior athletes (Group B), were not different (p > 0.05) from military young men (Group A), although they were significantly lower (p < 0.001) in Group C patients; wall elasticity was lower in Group C patients (versus both Group A and B). Altered compliance might be the consequence of vessel structural changes and may contribute to reduce blood flow to the coronary arteries. Our data suggest that sports activity has beneficial effects; physical characteristics of great vessels do not show age-related changes.