Safety and efficacy of off-pump coronary artery bypass grafting in chronic dialysis patients

Off-pump coronary artery bypass grafting (CABG) has been recently revived, because cardiopulmonary bypass (CPB) appears to worsen the multiple organ dysfunction after conventional CABG. To evaluate the safety and efficacy of the off-pump CABG in chronic dialysis patients, we compared the perioperative morbidity and mortality between 15 dialysis patients who underwent off-pump CABG at our center over the past 8 years with that of a concurrent group of 19 patients who underwent conventional CABG. Patients were selected for off-pump CABG only when complete revascularization was technically feasible. We found that off-pump CABG is as safe and effective as conventional CABG in selected dialysis patients. It might even be beneficial, because it is associated with less hematocrit drop and blood product use, a lower catabolic rate, and fewer dialysis requirements after surgery. However, the impact of off-pump technique on the long-term clinical outcome and resource utilization in renal patients requires further investigation.     

Comparison of electrical velocimetry and cardiac magnetic resonance imaging for the non-invasive determination of cardiac output

A novel algorithm of impedance cardiography referred to as electrical velocimetry (EV) has been introduced for non-invasive determination of cardiac output (CO). Previous validation studies yielded diverging results and no comparison with the non-invasive gold standard cardiac magnetic resonance imaging (CMR) has been performed. We therefore aimed to prospectively assess the accuracy and reproducibility of EV compared to CMR. 152 consecutive stable patients undergoing CMR were enrolled. EV measurements were taken twice before or after CMR in supine position and averaged over 20 s (AESCULON^®, Osypka Medical, Berlin, Germany). Bland–Altman analysis showed insufficient agreement of EV and CMR with a mean bias of 1.2 ± 1.4 l/min (bias 23 ± 26 %, percentage error 51 %). Reproducibility was high with 0.0 ± 0.3 l/min (bias 0 ± 8 %, percentage error 15 %). Outlier analysis revealed gender, height, CO and stroke volume (SV) by CMR as independent predictors for larger variation. Stratification of CO_CMR in quintiles demonstrated a good agreement for low values (<4.4 l/min) with bias increasing significantly with quintile as high as 3.1 ± 1.1 l/min (p < 0.001). Reproducibility was not affected (p = 0.71). Subgroup analysis in patients with arrhythmias (p = 0.19), changes in thoracic fluid content (p = 0.51) or left heart failure (p = 0.47) could not detect significant differences in accuracy. EV showed insufficient agreement with CMR and good reproducibility. Gender, height and increasing CO and SV were associated with increased bias while not affecting reproducibility. Therefore, absolute values should not be used interchangeably in clinical routine. EV yet may find its place for clinical application with further investigation on its trending ability pending.     

A hybrid approach for quantification of aortic valve stenosis using cardiac magnetic resonance imaging and echocardiography.

BACKGROUND: Doppler-derived calculation of aortic valve area (AVA) using the continuity equation can be difficult at times, e.g. due to poor acoustic windows, heavy calcification of the aortic valve, or significant flow acceleration in the left ventricular outflow tract. The aim of this study was to compare AVA as assessed by means of transthoracic echocardiography (TTE) with a hybrid approach, where the Doppler-derived numerator in the continuity equation was replaced by cardiovascular magnetic resonance (CMR) determination of stroke volume. METHODS: Twenty consecutive patients admitted for evaluation of aortic stenosis underwent transthoracic echocardiography and CMR determination of stroke volume within a time period of 3 weeks. Additionally, continuous-wave Doppler spectra of the aortic valve were acquired immediately after the CMR examination. RESULTS: There was no statistically significant difference for mean AVA between the two methods (0.88 +/- 0.23 cm2 by the standard continuity equation versus 0.86 +/- 0.23 cm2 by the hybrid approach, p = 0.55; r = 0.73, p < 0.01). The mean difference was 0.02 cm2 and the limits of agreement were -0.32 to 0.36. Only 2 patients were classified differently by the two methods. Intraobserver and interobserver variability and reproducibility were superior for the hybrid approach. CONCLUSION: The hybrid method for determination of AVA is an excellent alternative to the standard approach by TTE.     

Accuracy of one- and two-dimensional algorithms with optimal image plane position for the estimation of left ventricular mass: a comparative study using magnetic resonance imaging.

The commonly recommended one-dimensional (ID) and two-dimensional (2D) algorithms for left ventricular (LV) mass calculation are limited by assumptions about ventricular geometry and image plane position. To assess the accuracy of these algorithms after eliminating errors associated with image plane position, LV mass was calculated from high quality cardiovascular magnetic resonance imaging (CMR) data sets using ID (modified cube formula; MCF) and 2D algorithms [area-length (AL) and truncated ellipsoid (TE) methods], and the summation of slices (SS) method as reference technique in 25 patients with LV aneurysms, 15 patients with hypertrophic cardiomyopathy, and 10 healthy subjects. Each algorithm in each group overestimated LV mass compared to SS (p <0.05 and p<0.001). In each patient group, the smallest bias to the reference method was observed for the TE algorithm (p<0.001 vs. MCF and p < 0.05 vs. AL). The LV mass interval encompassing the limits of agreement was 120-220 g for MCF, 100-148 g for AL, and 80-136 g for TE. The interstudy reproducibility of the SS technique for the assessment of LV mass was superior compared to the ID and 2D algorithms. We conclude that despite the use of optimized image plane position ID and 2D algorithms are inaccurate for calculation of LV mass in ventricles with normal and distorted LV geometry. Thus, 3D imaging techniques, such as CMR, should be preferred when assessing LV mass.     

The Impact of Pulmonary Disease on Noninvasive Measurement of Cardiac Output by the Inert Gas Rebreathing Method

Cardiac output (CO) is an important parameter for diagnosis and therapy of heart diseases, but it is still difficult to determine. Innocor, a novel noninvasive inert gas rebreathing (IGR) system, has shown promising results. However, the impact of pulmonary diseases on IGR remains unclear. The aim of the study therefore was to assess the accuracy and reliability of IGR in patients with distinct chronic lung disease. A total of 96 patients were enrolled, including 48 consecutive patients with variant lung diseases (group A) and 48 pair-matched pulmonary healthy patients (group B). CO was measured with cardiac magnetic resonance imaging (CMR) and IGR. Lung function testing was done by spirometry [FEV₁/FVC (forced expiratory volume in one second/forced vital capacity), VC (vital capacity)] and determination of the diffusing capacity of the lung for carbon monoxide divided by alveolar volume (DLCO/VA). In group A we found a mean CO of 4.7 ± 1.3 L/min by IGR and 4.9 ± 1.2 L/min by CMR. Group B showed a mean CO of 4.8 ± 1.4 L/min by IGR and 5.0 ± 1.3 L/min by CMR. Bland–Altman analysis revealed good correspondence between CMR and IGR, with an average deviation of 0.1 ± 1.0 L/min in group A and 0.1 ± 1.0 L/min in group B (p = 0.99). Multiple regression analysis for the pulmonary parameters did not show a statistically significant impact on the mean bias of CO measurements (FEV₁/FVC: r = 0.01, p = 0.91; VC: r = ?0.2, p = 0.13; and DLCO/VA: r = 0.04, p = 0.82). IGR allows a feasible determination of CO even in patients with lung diseases. The accuracy of the IGR method is not influenced by either pulmonary obstructive and restrictive diseases or a reduced DLCO.     

Validation of the peak to mean pressure decrease ratio as a new method of assessing aortic stenosis using the Gorlin formula and the cardiovascular magnetic resonance-based hybrid method

BACKGROUND: We sought to validate the recently introduced peak to mean pressure decrease ratio (PMPDR), using the Gorlin formula and a hybrid method which combines cardiovascular magnetic resonance (CMR)-derived stroke volume with transaortic Doppler measurements to calculate aortic valve area (AVA). METHODS: Data analysis in 32 patients with severe (AVA 相似文献   

Fatigue resistance during high-intensity intermittent exercise from childhood to adulthood in males and females

This study examined the maturation pattern of fatigue resistance (FR) from childhood to adulthood in females and males during high-intensity intermittent exercise and compared FR between females and males in childhood and adolescence. Thirty males (boys 11.3 ± 0.5 years, teen-males 14.7 ± 0.3 years, men 24.0 ± 2.1 years) and 30 females (girls 10.9 ± 0.6 years, teen-females 14.4 ± 0.7 years, women 25.2 ± 1.4) participated in this study. They performed high-intensity intermittent exercise (4 × 18 maximal knee flexions and extensions with 1-min rest) on an isokinetic dynamometer at 120°s⁻¹. Peak torque of flexors (PTFL) and extensors (PTEX), and total work (TW) were measured. FR was calculated as % of PTEX, PTFL, and TW in 4th versus 1st set. FR was greater (P < 0.05) in boys versus teen-males and men, and in teen-males versus men. In females, FR was greater (P < 0.05) in girls versus teen-females and women, but not different between teen-females and women. FR was not different in boys versus girls and in teen-males versus teen-females. FR for PTFL, PTEX, and TW correlated negatively (P < 0.001) with the respective peak values (r = −0.68 to −0.84), and FR for TW with peak lactate (r = −0.58 to −0.69). In addition, age correlated (P < 0.01) with FR for males (r = −0.75) and females (r = −0.55). In conclusion, FR during high-intensity intermittent exercise undergoes a gradual decline from childhood to adulthood in males, while in females the adult profile establishes at mid-puberty (14–15 years). The maturation profile of FR in males and females during development appears to reflect the maturation profiles of peak torque, short-term muscle power, and lactate concentration after exercise. T. Tsirini and A. Zafeiridis contributed equally to this work.