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.
ObjectiveTo explore the anatomical characteristics and surgical strategies of atrioventricular septal defect (AVSD) with left ventricular outflow tract (LVOT) stenosis.MethodsThe clinical data of 11 AVSD patients with LVOT stenosis who underwent surgeries in our hospital from 2008 to 2019 were retrospectively analyzed, including 6 males and 5 females with a median age of 15.0 (7.6-22.0) years.ResultsThere were 3 patients of complete AVSD and 8 patients of partial AVSD. Subaortic stenosis resulted from discrete subaortic membrane in 3 patients, diffused subaortic membrane in 4 patients, hypertrophied muscle bundles in 3 patients and distorted valve frame in 1 patient. Among these patients, 5 patients underwent LVOT stenosis and AVSD repairs simultaneously for the first time, 5 patients underwent LVOT stenosis repair for the second time and 1 patient for the third time. No postoperative death occurred. The postoperative LVOT flow velocity decreased dramatically after LVOT stenosis repair compared with preoperative one [449.0 (393.0, 507.5) cm/s vs. 212.0 (183.0, 253.5) cm/s, P<0.05].ConclusionSurgical results of AVSD combined with LVOT stenosis are satisfactory, but the restenosis should be paid attention to via long-term follow-up.
ObjectiveTo analyze the early outcomes of anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) patients with severe left ventricular dysfunction after surgical repair, and to explore the predictors for extracorporeal membrane oxygenation (ECMO) support for these patients.MethodsThe clinical data of ALCAPA patients with severe left ventricular dysfunction (left ventricular ejection fraction<40%) who underwent coronary artery reimplantation in the pediatric center of our hospital from 2013 to 2020 were retrospectively analyzed. The patients were divided into an ECMO group and a non-ECMO group. Clinical data of the two groups were compared and analyzed.ResultsA total of 64 ALCAPA patients were included. There were 7 patients in the ECMO group, including 4 males and 3 females aged 6.58±1.84 months. There were 57 pateints in the non-ECMO group, including 30 males and 27 females aged 4.34±2.56 months. The mortality of the patients was 6.25% (4/64), including 2 patients in the ECMO group, and 2 in the non-ECMO group. The postoperative complications rate was significantly higher in the ECMO group than that in the non-ECMO group (P=0.041). There were statistical differences in the cardiopulmonary bypass time [254 (153, 417) min vs. 106 (51, 192) min, P=0.013], aortic cross-clamping (ACC) time (89.57±13.66 min vs. 61.58±19.57 min, P=0.039), and preoperative left ventricular end-diastolic diameter/body surface area (132.32±14.71 mm/m2 vs. 108.00±29.64 mm/m2, P=0.040) between the two groups. Multivariate logistic regression analysis showed that ACC time was an independent risk factor for postoperative ECMO support (P=0.005). Receiver operating characteristic (ROC) curve analysis showed that the area under the ROC curve was 0.757, the sensitivity was 85.70%, specificity was 66.70%, with the cut-off value of 66 min.ConclusionACC time is an independent risk factor for postoperative ECMO support. Patients with an ACC time>66 min have a significantly higher risk for ECMO support after the surgery.
ObjectiveTo summarize the experience of surgical treatment of transposition of the great arteries with intact ventricular septal (TGA-IVS) after left ventricular regression by comparing the characteristics of rapid and long-term two-stage arterial switch operation (ASO).MethodsForty-one patients who were mainly diagnosed with TGA-IVS from January 2007 to January 2019 and underwent two-stage ASO were included. They were divided into a rapid two-stage ASO group (19 patients) and a long-term two-stage ASO group (22 patients) according to the interval of left ventricular training surgery and ASO. The clinical effectiveness of the two groups was compared.ResultsThere was a statistical difference in age, body weight, blood oxygen saturation before ASO, end diastolic diameter of left ventricle before training, and thickness of posterior left ventricular wall before ASO (P<0.05). Children older than 1 year was an independent risk factor for long-term two-stage ASO.ConclusionLong-term two-stage ASO is suitable for children who are older than 1 year and who have severe left ventricular regression.
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.
Objective We probed how to predict left ventricular ejection fraction (LVEF) of the ischaemic cardiomyopathy (ICM) patients would be improved apparently after revascularization. Methods Between July 2010 and December 2015, 245 ICM patients (30%≤LVEF≤40%) with coronary bypass grafting (CABG) were retrospectively observed. Among them, 146 patients were accompanied by ischemic mitral regurgitation (IMR) (146/245, 59.6%), and 41 patients underwent mitral valvuloplasty or replacement because of more than moderate IMR. There were 13 patients early death, and other 232 patients who were followed up over 6 months were divided into two groups based on whether or not post-operative LVEF increased by 10%: a LVEF recovered group (group A, 124 patients) and a non-recovered group (group B, 108 patients). Results Preoperative NT-proBNP in the group A was significantly higher than that in the group B (P=0.036). There were less patients with myocardial infarction in the group A than that in the group B (P=0.047), and more with angina pectoris in the group A than that in the group B (P=0.024). There was no significant difference in the extent of mitral regurgitation or mitral surgery between the groups A and B (P>0.05). There were lower left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD) and left ventricular end-diastolic volume (LVEDV) in the group A than those in the group B (P<0.05). Multivariate analysis revealed that preoperative LVEDD dilated apparently and no angina pectoris existed before surgery were independent risk factors for LVEF with no recovery in the ICM patients (30%≤LVEF≤40%) after revascularization. The LVEDD of 245 patients (including 13 early deaths) was 41-71 mm. We found that the ICM patients with LVEDD ≥60 mm were more likely to signify the unfavourable prognosis (χ2=8.63, P=0.003, OR=2.21, 95% confidence interval 1.25 to 3.91). Conclusion Preoperative LVEDD dilated and no angina pectoris before surgery are independent risk factors for LVEF with no recovery in the ICM patients (30%≤LVEF≤40%) after revascularization. LVEDD≥60 mm can be regarded as the preoperative forecasting factors for the unfavourable prognosis in the ICM patients (30%≤LVEF≤40%) after revascularization.
ObjectiveTo explore the operative strategy after palliative shunt for correcting congenitally corrected transposition of great artery (cTGA) patients with left ventricular outflow tract obstruction (LVOTO) and cardiac malpostion.MethodsWe retrospectively analyzed the clinical data of 54 patients with onsecutive cTGA with LVOTO and cardiac malpositon from June 2011 to May 2019. The patients were devided into two groups. There were 24 patients (16 males and 8 females at mean age of 5.4±2.2 years) who underwent one and a half ventricle repair as a one and half ventricle group. And there were 30 patients (19 males and 11 females at age of 8.6±6.2 years) who underwent one ventricle repair operation as a one ventricle group. Follow-up data were collected by telephone interviews.ResultsThere was no statistical difference in systemic atrioventricular valve regurgitation and systemic ventricular ejection fraction between the two groups (P>0.05). Compared with one and a half ventricle group, the cardiopulmonary bypass time (CPB) time, mechanical ventilation time and intensive care unit stay were significant shorter than those in the one ventricle group (P<0.05), but prolonged pleural effusions developed more frequently in the one ventricle repair group (P<0.05). There was no in-hospital death but 1 follow-up death in each group. The follow-up time was 49 (17-38) months in the one and half ventricle group at follow-up rate of 93.9%, and 47 (12-85) months at follow-up rate at 90.9% in the one ventricle group. One and a half ventricle group had better systemic ventricular ejection fraction (EF) than that in the one ventricle repair group. And the rate of heart function (NYHA) class Ⅲ and class Ⅳ in one and a half ventricle group was lower than that in the ventricle group. No significant difference of survival and freedom from re-intervention probability between the two groups was found.ConclusionFor patients of correction of cTGA with LVOTO and cardiac malposition after palliative shunt, the one-and-a-half ventricular repair procedure is ideal operative strategy.
Objective To identify the relationship between preoperative left ventricular dysfunction and perioperative risk factors in coronary artery bypass grafting (CABG). Methods The clinical data of 192 patients who underwent CABG from November 2015 to October 2016 were analyzed retrospectively. The patients were divided into three groups by preoperative left ventricular ejection fraction (LVEF) in echocardiography: a serious left ventricular dysfunction group (LVEF≤35%, 23 patients, 15 males and 8 females at age of 63.91±5.36 years), a moderate left ventricular dysfunction group (35%<LVEF<50%, 24 patients, 20 males and 4 females at age of 66.29±6.03 years) and a normal left ventricular function group (LVEF≥50%, 145 patients, 86 males and 59 females at age of 66.60±6.41 years). Results The overall mortality was 4.16% (8/192), 17.39% (4/23) in patients with LVEF≤35% and 2.76% (4/145) in those with LVEF≥50%. Preoperative LVEF≤35%, hypoxia, assisted circulation, acute kidney injury (AKI) and postoperative continuous renal replacement therapy (CRRT) were risk factors of perioperative mortality in coronary artery surgery. LVEF≤35% and CRRT were independent preditors of mortality. There were significant differences in mortality and postoperative complications between the serious left ventricular dysfunction group and other two groups. Conclusion Postoperative mortality and complications are obviously serious in the patients with LVEF≤35%. We should pay more attention to preoperative risk factors. Postoperative individual manipulation, intra-aortic balloon pump and CRRT can enhance survival of those patients.
ObjectiveTo explore the value of transthoracic echocardiography (TTE) to monitor and evaluate aortic insufficiency (AI) within one year after the implantation of the left ventricular assist device (LVAD).MethodsWe retrospectively collected and analyzed the TTE data of 12 patients who received LVAD implantation from 2018 to 2020 in our hospital. All patients were males, with an average age of 43.3±8.6 years. We analyzed temporal changes in the aortic annulus (AA), aortic sinus (AoS), ascending aorta (AAo), the severity of AI and the opening of aortic valve before operation and 1 month, 3 months, 6 months and 12 months after LVAD implantation.ResultsAll 12 patients survived within 1 year after LVAD implantation. One patient was bridged to heart transplantation 6 months after implantation, and two patients did not receive TTE after 3 and 6 months. Compared to pre-implantation, AoS increased at 1 month after implantation (31.58±5.09 mm vs. 33.83±4.69 mm). The inner diameters of AA, AoS and AAo increased at 3, 6 and 12 months after LVAD implantation compared to pre-implantation (P<0.05), but all were within the normal range except for one patient whose AoS slightly increased before operation. After LVAD pump speed was adjusted, the opening of aortic valve improved. The severity of AI increased at 6 and 12 months after LVAD implantation compared to pre-implantation, and increased at 12 months compared to 6 months after LVAD implantation (P<0.05).ConclusionTTE can evaluate aortic regurgitation before and after LVAD implantation and monitor the optimization and adjustment of LVAD pump function, which has a positive impact on the prognosis after LVAD implantation.
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.