Objective To investigate surgical outcomes and prognostic factors for patients with coronary heart disease and low left ventricular ejection fraction （LVEF≤40%） undergoing off-pump coronary artery bypass grafting （OPCAB）. Methods We retrospectively analyzed clinical records of 63 discharged patients with coronary heart disease and low LVEF who underwent OPCAB in Peking University People’s Hospital from 2001 to 2004 year. There were 48 males and 15 females with mean age of 65.1±9.2 years and mean LVEF of 33.8%±5.0%. Regular follow-up evaluation was completed. We investigated risk factors for long-term survival of the patients by Kapalan-Meier survival curve, log-rank test and Cox regression model.?Results?Follow-up time was 3-107 （71.3±24.4） months, and six patients were lost during the follow-up. Nineteen patients （30.2%） died during follow-up including 10 patients （15.9%） who had cardiac-related death. The survival rate at 1, 3, 5 and 8 year was 96.7% （61）, 94.9% （60）, 85.9% （55）, 77.2% （53） respectively. Univariate analysis shows LVEF≤30% and acute myocardial infarction within 30 days are risk factors for long-term survival（P＜0.05）. Cox regression analysis showed that LVEF≤30%（RR=4.662, P＜0.05）and acute myocardial infarction within 30 days（RR=5.544, P＜0.05）were two independent risk factors for cardiac-related death after discharge. Conclusion Patients with coronary heart disease and low LVEF can have satisfactory surgical outcomes after OPCAB. LVEF≤30% and acute myocardial infarction within 30 days are the two independent risk factors for cardiac-related death after discharge.
Objective To investigate the feasibility of a long-term left ventricular assist device placed in the aortic valve annulus for terminal cardiopathy. Methods An implantable aortic valve pump （23ram outer diameter, weighing 31g） was developed. There were a central rotor and a stator in the device. The rotor was consisted of driven magnets and an impeller, the stator was consisted of a motor coil with an iron core and outflow guide vanes. The device was implanted identical to an aortic valve replacement, occupying no additional anatomic space. The blood was delivered directly from left ventricle to the aortic root by aortic valve pump like natural ventricle, neither connecting conduits nor ＂bypass＂ circuits were necessary, therefore physiologic disturbances of natural circulation was less. Results Aortic valve pump was designed to cycle between a peak flow and zero net flow to approximate systole and diastole. Bench testing indicated that a blood flow of 7L/min with 50 mmHg（1kPa = 7.5mmHg） pressure could be produced by aortic valve pump at 15 000r/min. A diastole aortic pressure of 80mmHg could be maintained by aortic valve pump at 0L/min and the same rotating speed. Conclusions This paper exhibits the possibility that an aortic valve pump with sufficient hemodynamic capacity could be made in 23mm outer diameter, 31g and it could be implantable. This achievement is a great progress to extend the applications of aortic valve pump in clinic and finally in replacing the natural donor heart for heart transplantation. Meanwhile, this is only a little step, because many important problems, such as blood compatibility and durability, require further investigation.
The present study aimed to investigate the impact of hypothyroidism on left ventricular systolic function using real-time three-dimensional speckle tracking imaging (RT3D-STI). Thirty hypothyroidism patients and forty healthy volunteers were recruited and received RT3D-STI measurement of global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), and global area strain (GAS). A comparison of differences between the hypothyroidism patients and those in the healthy group was carried out and we obtained the results as followings. The values of GLS were (-18.93°3.89) vs. (-21.44°1.99), with P<0.01, GRS were (51.13°11.95) vs. (56.10°5.76), with P<0.0; and GAS were (-31.63°5.38) vs. (-34.40°2.32), with P<0.01, i.e. they were lower in hypothyroidism group than those in the health group. While GCS were (-17.75°1.92) vs. (-17.03°3.45), with P>0.05, which were not significantly different between the two groups. In linear regression, GLS showed significant correlation with both TSH (b=-0.69, P<0.01) and FT3(b=0.71, P<0.01). Meanwhile, the GRS (b=2.98, P<0.05) and GAS (b=3.11, P<0.05) linearly correlated with FT3 level. In conclusion, the present study shows that the global longitudinal and radial moves of left ventricular are weaker in patients with hypothyroidism than healthy controls. And the impairment of left ventricular function would aggravate as FSH rises or FT3 declines.
To evaluate the value of left ventricular diastolic function in type 2 diabetes mellitus (DM) using dual-gate Doppler and relative factors, we included 50 non-obesity and hypertension-free DM patients into the controlled group in the study along with 48 age-and-gender-matched healthy volunteer subjects. The peak early diastolic velocity (E), peak later diastolic velocity (A), deceleration time (DT), anterior mitral annulus diastolic peak velocity (e'), isovolumic relaxation time (IVRT), E/A, E/e', Tei index and TE-e' were measured with dual-gate Doppler. 20 subjects were randomly selected for repetitive analysis. Study showed statistical difference in E/A, DT, e', E/e', IVRT, Tei index and TE-e' between the two groups (P < 0.05). Linear regression analysis showed positive correlation between TE-e' and IVRT, course of DM patients and TE-e'(Beta=0.295, P=0.020), and HbA1C control level and TE-e'(Beta=0.399, P=0.010). Repeated analysis showed good reproducibility for both within and between groups. Dual-gate Doppler has clinical value in evaluating left ventricular diastolic function in type 2 diabetes mellitus patients. The course of type 2 diabetes mellitus patients and HbA1C control level were both closely related with left ventricular diastolic function.
The aim of this study is to analyze the concordance between EDV, ESV and LVEF values derived from 18F-FDG PET, GSPECT and ECHO in patients with myocardial infarction. Sixty-four patients with coronary artery disease (CAD) and myocardial infarction were enrolled in the study.. Each patient underwent at least two of the above mentioned studies within 2 weeks. LVEF、 EDV and ESV values were analyzed with dedicated software. Statistical evaluation of correlation and agreement was carried out EDV was overestimated by 18F-FDG PET compared with GSPECT [(137.98±61.71) mL and (125.35±59.34) mL]; ESV was overestimated by 18F-FDG PET (85.89±55.21) mL and GSPECT (82.39±55.56) mL compared with ECHO (68.22±41.37) mL; EF was overestimated by 18F-FDG PET (41.96%±15.08%) and ECHO (52.18%±13.87%) compared with GSPECT (39.75%±15.64%), and EF was also overestimated by 18F-FDG PET compared with GSPECT. The results of linear regression analysis showed good correlation between EDV, ESV and LVEF values derived from 18F-FDG PET, GSPECT and ECHO (r=0.643-0.873, P=0.000). Bland-Altman analysis indicated that 18F-FDG PET correlated well with ECHO in the Left ventricular function parameters. While GSPECT correlated well with 18F-FDG PET in ESV, GSPECT had good correlation with Echo in respect of EDV and EF; whereas GSPECT had poor correlation with PET/ECHO in the remaining left ventricular function parameters. Therefore, the clinical physicians should decide whether they would use the method according to the patients' situation and diagnostic requirements.
Objective To evaluate the relationship between pattern of left ventricular dilation and functional mitral regurgitation (FMR) by echocardiography. Methods A single-center retrospective observational study was conducted on 117 patients with age of 31-77 years and left ventricular end diastolic dimension≥60 mm treated in our hospital from January 2013 through May 2016. These patients were divided into four groups by FMR degree: FMR-None/Trace (FMR-N/T group,n=33), FMR-Minor (FMR-Mi group,n=37), FMR-Moderate (FMR-Mo group,n=34) and FMR-Severe (FMR-Se group,n=13). We analyzed their basic information and echocardiographic parameters including left ventricular dimension, volume, systolic function, spherical index, regional wall motion score index, tenting height and area of mitral vavle as well as anterior/posterior angle. Results The incidences of inferior/posterior/lateral myocardial infarction and basal myocardial dyskinesia/aneurysm increased with the increase of FMR degree (FMR-N/T vs. FMR-Mi vs. FMR-Mo vs. FMR-Se: 12.1% vs. 18.9% vs. 44.1% vs. 46.2%,P=0.001 and 12.1% vs. 27.0% vs.47.1% vs. 53.8%,P=0.005, respectively). The tenting height and area of mitral valve, anterior/posterior angle, regional wall score index of the left ventricle where the papillary muscle was attached to had a positive correlation with FMR degree (P＜0.05). Conclusion There is a relationship between regional left ventricular dilation and FMR. Evaluating and improving those parameters is very important when we choose the treatment strategy of functional mitral regurgitaion.
We propose a control model of the cardiovascular system coupled with a rotary blood pump in the present paper. A new mathematical model of the rotary heart pump is presented considering the hydraulic characteristics and the similarity principle of pumps. A seven-order nonlinear spatial state equation adopting lumped parameter is used to describe the combined cardiovascular-pump model. Pump speed is used as the control variable. To achieve sufficient perfusion and to avoid suction, a feedback strategy based on minimum (diastolic) pump flow is used in the control model. The results showed that left ventricular assist device (LVAD) could improve hemodynamics of the cardiovascular system of the patient with heart failure in open loop. When rotation speed was 9,000 r/min, cardiac output reached 82 mL/s while the initial cardiac output was only 34 mL/s without the LVAD support. When the rotation speed was above 12 800 r/min, suction was found because the high rotating speed resulted in insufficient venous return volume. Suction was avoided by adopting the feedback control. The model reveals the interaction of LVAD and the cardiovascular system, which provides theoretical basis for the therapy of heart failure in the left ventricular and for the design of a physiological control strategy.
We have tried to explore the energy loss (EL) within the left ventricle in hypertension by using vector flow mapping (VFM) to detect left ventricular hemodynamic changes in hypertensive patients as early as possible and reflect changes of left ventricular function in hypertension by using EL. Twenty-one hypertensive patients with increased left ventricle mass index (LVMI), 14 hypertensive patients with normal LVMI and 22 control subjects were enrolled in this study. Systolic and diastolic EL derived from VFM within the left ventricle and E/e' by dual Doppler were recorded and analyzed. Compared with those of the controls, diastolic and systolic EL were significantly increased in hypertensive group (P<0.05). In diastole, EL=0.439×SBP (systolic blood pressure)–8.349; in systole, EL=0.385×SBP+0.644×LVMI–10.854. And the EL was positively correlated with E/e', but there was no significant correlation between EL and ejection fraction (EF) in the pooled population. The study shows that the increased EL can help us detect changes of left ventricular hemodynamic in hypertensive patients. It needs further investigation to prove whether EL within the left ventricle could be a new parameter to evaluate diastolic function. SBP and LVMI are the independent predictors for systolic EL, while SBP is the independent predictor for diastolic EL.
The continuous left ventricle blood pressure prediction based on selected heart sound features was realized in this study. The experiments were carried out on three beagle dogs and the variations of cardiac hemodynamics were induced by various dose of epinephrine. The phonocardiogram, electrocardiogram and blood pressures in left ventricle were synchronously acquired. We obtained 28 valid recordings in this study. An artificial neural network was trained with the selected feature to predict left ventricular blood pressure and this trained network made a good performance. The results showed that the absolute average error was 7.3 mm Hg even though the blood pressures had a large range of fluctuation. The average correlation coefficient between the predicted and the measured blood pressure was 0.92. These results showed that the method in this paper was helpful to monitor left ventricular hemodynamics non-invasively and continuously.
Regurgitation is an abnormal condition happens when left ventricular assist devices (LVADs) operated at a low speed, which causes LVAD to fail to assist natural blood-pumping by heart and thus affects patients’ health. According to the degree of regurgitation, three LVAD’s regurgitation states were identified in this paper: no regurgitation, slight regurgitation and severe regurgitation. Regurgitation index (RI), which is presented based on the theory of dynamic closed cavity, is used to grade the regurgitation of LVAD. Numerical results showed that when patients are in exercising, resting and sleeping state, the critical speed between slight regurgitation and no regurgitation are 6 650 r/min, 7 000 r/min and 7 250 r/min, respectively, with corresponding RI of 0.401, 0.300 and 0.238, respectively. And the critical speed between slight regurgitation and severe regurgitation are 5 500 r/min, 6 000 r/min and 6 450 r/min, with corresponding RI of 0.488, 0.359 and 0.284 respectively. In addition, there is a negative relation correction between RI and rotational speed, so that grading the LVAD’s regurgitation can be achieved by determining the corresponding critical speed. Therefore, the detective parameter RI based on the signal of flow is proved to be able to grade LVAD’s regurgitation states effectively and contribute to the detection of LVAD’s regurgitation, which provides theoretical basis and technology support for developing a LVADs controlling system with high reliability.