Incremental Value of Left Atrial Function Analysis in the Assessment of Left Ventricular Filling Pressures in Patients with ST-Elevation Myocardial Infarction.

Background: Left atrial (LA) reservoir strain provides interesting information about left ventricular (LV) filling pressure. However, the advantages of atrial reservoir strain in comparison with conventional parameters in patients with myocardial infarction are not clear yet. Methods: Fifty patients with ST-elevation myocardial infarction (STEMI) prospectively underwent echocardiographic assessment of LV systolic and diastolic function by conventional parameters and two-dimensional speckle tracking longitudinal strain of left atrium. LV filling pressure was estimated by brain natriuretic peptide (BNP) levels. Results: Systolic and conventional diastolic parameters did not show significant differences between patients with increased and normal BNP values, whereas LA reservoir strain was reduced (33.1 ± 8% vs. 46.5 ± 9.8%; P = 0.001) in patients with higher BNP levels. LA reservoir strain had higher area under curve value (0.880) than the other parameters in identifying patients with elevated BNP and a cut-off value of 40.5% reached sensitivity and specificity values of 93% and 86% and positive and negative predictive values of 92% and 85%. LA reservoir strain reclassified 23 patients with increased BNP values, which were previously estimated to have normal (16 patients) and undeterminable LA pressure (seven patients) by using the recommended algorithm for diastolic function. Conclusions: LA reservoir strain is a useful tool for the evaluation of diastolic function and seems to be more sensitive than conventional parameters in the detection of subtle increase of LV filling pressure in patients with STEMI. It allows physicians to reclassify patients with undeterminable diastolic function according to conventional algorithm.

Preliminary In Vitro Wear Assessment of Ceramic Cemented Femoral Components Coupled with Polyethylene Menisci.

Success of total knee replacement (TKR) depends on the prosthetic design and materials. The use of metal components is well established with the disadvantage of allergic reactions. Ceramics have been recently proposed because of high wear resistance, excellent biocompatibility, wettability, and suitable mechanical properties. This study was aimed at investigating in vitro wear resistance of Zirconia Toughened Alumina (ZTA)/Ultra-high-molecular-weight polyethylene (UHMWPE) of TKR femoral components. An in vitro protocol was designed with the application of relevant load profile, 6-degrees-of-freedom knee simulator, and 8 × 105 cycles on the ZTA/UHMWPE configuration under bovine calf serum. Before and after wear test, the femoral components were investigated by using the Scanning Electron Microscope (SEM) and the X-Ray Diffraction (XRD) analyses, and stylus surface roughness measurements. The proposed pre-clinical test yielded repeatable results. In particular, gravimetric results showed that, after 8 × 105 cycles, the mean weight loss of the polyethylene mobile components is 5.3 ± 1.1 mg. The surface roughness measurements (Ramax) performed after the wear test showed no significant variation on the UHMWPE menisci. A slight increase of roughness has been found on the ZTA (0.02 µm before wear test, 0.28 µm after the test). SEM observations did not show significant modification of the surface morphology. Tetragonal to monoclinic phase ratio was measured by XRD before and after wear test to evaluate stability of tetragonal ZrO2 phase. Minimal conversion of tetragonal to monoclinic phase was found from 5.4 to 8%. Although this study is a preliminary evaluation limited to in vitro tests, it provides novel pre-clinical indications about the potential of ceramic TKR femoral components.

Diastolic dysfunction evaluated by cardiac magnetic resonance: the value of the combined assessment of atrial and ventricular function.

OBJECTIVES: We sought to evaluate the role of cardiac magnetic resonance imaging (CMR) in the evaluation of diastolic function by a combined assessment of left ventricular (LV) and left atrial (LA) function in a cohort of subjects with various degrees of diastolic dysfunction (DD) detected by echocardiography. METHODS: Forty patients with different stages of DD and 18 healthy controls underwent CMR. Short-axis cine steady-state free precession images covering the entire LA and LV were acquired. Parameters of diastolic function were measured by the analysis of the LV and LA volume/time (V/t) curves and the respective derivative dV/dt curves. RESULTS: At receiver operating characteristic (ROC) curve analysis, the peak of emptying rate A indexed by the LV filling volume with a cut-off of 3.8 was able to detect patients with grade I DD from other groups (area under the curve [AUC] 0.975, 95% confidence interval [CI] 0.86-1). ROC analysis showed that LA ejection fraction with a cut-off of ≤36% was able to distinguish controls and grade I DD patients from those with grade II and grade III DD (AUC 0.996, 95% CI 0.92-1, p < 0.001). The isovolumetric pulmonary vein transit ratio with a cut-off of 2.4 allowed class III DD to be distinguished from other groups (AUC 1.0, 95%CI 0.93-1, p < 0.001). CONCLUSIONS: Analysis of LV and LA V/t curves by CMR may be useful for the evaluation of DD. KEY POINTS: • Combined atrial and ventricular volume/time curves allow evaluation of diastolic function. • Atrial emptying fraction allows distinction between impaired relaxation and restrictive/pseudo-normal filling. • Isovolumetric pulmonary vein transit ratio allows distinction between restrictive and pseudo-normal filling.

Detection of myocardial iron overload by two-dimensional speckle tracking in patients with beta-thalassaemia major: a combined echocardiographic and T2* segmental CMR study.

We aimed to evaluate the role of two-dimensional speckle tracking imaging (2DSTI) in detecting early changes of myocardial deformation in patients affected by thalassemia major (TM) and its relation with myocardial iron overload (MIO) detected by T2* cardiovascular magnetic resonance (CMR). We studied 28 TM patients (15 males, 37.4 ± 10 years). All patients underwent CMR and echocardiography in the same day. Segmental and global T2* values were measured. Values of global longitudinal strain (GLS) were derived from the three apical views, while radial and circumferential strain were obtained as average strain from the short axis views at basal, mid and apical level. Six patients (21.4%) showed significant MIO (global heart T2* < 20 ms). GLS showed a significant correlation with T2* values (R = -0.49; P = 0.001) and it was significantly lower in patients with a significant MIO than in those with no significant MIO (-18.3 ± 2 vs. -21.3 ± 2.7, P = 0.02). No significant difference was found for radial and circumferential strain in relation to the severity of MIO. Patients with impaired GLS (<-19.5%) had a significant higher risk of showing significant MIO (Odds-ratio-OR = 17; 95%). GLS is related with global T2* in TM patients. Moreover, GLS can identify TM patients with severe MIO detected by CMR.

Usefulness of late gadolinium enhancement MRI combined with stress imaging in predictive significant coronary stenosis in new-diagnosed left ventricular dysfunction.

BACKGROUND: To evaluate the accuracy of late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) and imaging stress test in predicting significant coronary artery disease (CAD) in left ventricular (LV) dysfunction. METHODS: We enrolled 187 consecutive out-patients (61±17years) with new evidence of depressed (<45%) ejection fraction and no history of previous heart diseases and absence of Q-waves. All patients underwent coronary angiography (CA) and to LGE-CMR examination to identify ischemic and non-ischemic LGE. All patients underwent stress imaging to determine the presence of myocardial ischemia. RESULTS: Ischemic-LGE was found in 83 patients and non-ischemic-LGE in 104. Significant CAD on CA was found in 86/187 patients. Ischemic-LGE showed a specificity of 94%, a sensitivity of 89% and an accuracy of 92% in identifying significant CAD. Imaging stress test was negative in 98/105 patients without CAD, and positive in 42/82 with significant CAD, showing a specificity of 93%, a sensitivity of 51% and an accuracy of 75% in identifying CAD. Combining CMR and stress test imaging, 94 patients had ischemic-LGE pattern and/or positive stress test for ischemia; of these 81/94 had significant CAD on CA and 13 had no CAD. Among the 93 patients with both tests negative, significant CAD was found in 5/93 patients. The combination of LGE and stress respect to only LGE did not improve the diagnostic accuracy (90 vs 92% respectively). CONCLUSION: LGE-CMR had high accuracy in predicting significant CAD in ischemic LV dysfunction or as a bystander in non ischemic dysfunction.

Left Atrial Morphology, Size and Function in Patients With Transthyretin Cardiac Amyloidosis and Primary Hypertrophic Cardiomyopathy　- Comparative Strain Imaging Study.

BACKGROUND: We sought to assess left atrial (LA) morphology and function in patients with transthyretin cardiac amyloidosis (TTR-CA) and hypertrophic cardiomyopathy (HCM). Primarily, longitudinal deformation (reservoir) and pump function were the focus of vector-velocity strain echocardiography imaging. METHODS AND RESULTS: The study group comprised 32 patients (mean age 57.7±15.4 years, 16 in each group), and 15 healthy controls. Diagnosis of TTR-CA was based on echocardiography and either gadolinium-enhanced (LGE) cardiac magnetic resonance (cMRI) or radionuclide imaging. At baseline, there were no differences in age, body surface area, blood pressure and risk factors among the groups. Left ventricular (LV) mass was greater in patients than in controls, and slight LA dilatation was found in the TTR-CA group. LA reservoir was 14.1±4.7% in TTR-CA, 20.0±5.6% in HCM, and 34.0±11.8% in controls (<0.001). In addition, LA pump function chiefly was impaired in the former group, irrespective of LA chamber size and LV ejection fraction. LGE in the atrial wall was seen in 9/10 TTR-CA versus 0/8 HCM patients undergoing cMRI (P<0.001). LA reservoir ≤19% and pump function ≤-1.1% best discriminated TTR-CA from HCM patients in the receiver-operating characteristic analysis. CONCLUSIONS: LA reservoir and pump function were significantly impaired in both TTR-CA and HCM patients compared with controls, but mainly in the former group, irrespective of LA volume and LV ejection fraction, likely caused by a more altered LA wall structure. (Circ J 2016; 80: 1830-1837).