Implantable left ventricular assist device (LVAD) has become an essential treatment for end-stage heart failure, and its effect has been continuously improved. In the world, magnetic levitation LVAD has become mainstream and is increasingly used as a destination treatment. China has also entered the era of ventricular assist device. The continuous improvement of the ventricular assist device will further improve the treatment effect. This article reviews the current situation and development trend of LVAD treatment in China and abroad.
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 To compare the clinical efficacy of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in patients with coronary heart disease and left ventricular systolic dysfunction. Methods A computer-based search in PubMed, The Cochrane Library and EMbase up to October 2017, together with reference screening, was performed to identify eligible clinical trials, cohort studies and case-control studies. The outcomes of this meta-analysis included all-cause mortality, myocardial infarction, revascularization and stroke, and the effect sizes for them were presented as relative risk (RR) with its 95% confidence intervals (CI). Results Fifteen cohort studies and 2 randomized controlled trials were finally included with a total of 11 985 patients, of whom 6 322 were in the CABG group and 5 663 in the PCI group. The result of meta-analysis showed that all-cause mortality was significantly lower in the CABG group than that in the PCI group (18.6% vs. 23.0%, RR=0.87, 95% CI 0.81 to 0.94, P<0.001). In addition, CABG was associated with a remarkably reduced risk of revascularization (RR=0.28, 95% CI 0.19 to 0.42, P<0.001) compared with PCI, with no significant difference in incidence of myocardial infarction (RR=0.78, 95% CI 0.47 to 1.32, P=0.36) and stroke (RR=1.28, 95% CI 0.89 to 1.86, P=0.18). Conclusion CABG is superior to PCI in the treatment for patients with coronary heart disease and left ventricular systolic dysfunction. Owing to the limited quality of included studies, additional large, randomized controlled trails are still required to confirm this finding.
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.
Objective To retrospectively reviewed our experience of the surgical and perioperative treatment of patients suffering from critical Marfan syndrome with severe left ventricular dysfunction and to evaluate its therapeutic effect and prognosis. Methods Between January 2012 and October 2016, 15 patients diagnosed with Marfan syndrome combined with severe left ventricular dysfunction (left ventricular ejection fraction≤40% or left ventricular end diastolic diameter≥75 mm) underwent operations for aortic root aneurysm in Zhujiang Hospital and Guangdong General Hospital. Among them, 11 were males and 4 were females with a mean age of 32.9±8.7 years ranging from 19 to 55 years. Five patients with aortic dissection underwent Bentall procedure and total arch reconstruction with stent graft implantation. Two patients underwent Bentall procedure and hemi-arch replacement, seven patients underwent Bentall procedure and one patient underwent Cabrol procedure. Concomitant procedures included mitral valve repair in 12 patients, mitral valve replacement in 3 patients and tricuspid valve repair in 12 patients. Results There were 11 patients (73.3%) receiving intra-aortic balloon pumping implantation. One (6.7%) in-hospital death occurred. The left ventricular end diastolic diameter decreased from 80.5±7.4 mm to 58.3±6.0 mm (P<0.05) and the left ventricular ejection fraction improved from 37.3%±5.2% to 46.3%±4.4% 3 months postoperatively (P<0.05). The left ventricular end diastolic diameter decreased from 80.5±7.4 mm to 53.7±3.6 mm (P<0.05) and the left ventricular ejection fraction improved from 37.3%±5.2% to 57.7%±4.2% after one year (P<0.05). No death and reoperation occurred in the follow-up. Conclusion Although the patients with Marfan syndrome and severe left ventricular dysfunction usually have a high surgical mortality, the key to satisfactory outcomes of severe Marfan syndrome is adequate preoperative preparation, complete correction of all vascular lesions during the operation, application of circulatory auxiliary device and perioperative strict and long-term ICU monitoring.
The rotary left ventricular assist device (LVAD) has been an effective option for end-stage heart failure. However, while clinically using the LVAD, patients are often at significant risk for ventricular collapse, called suction, mainly due to higher LVAD speeds required for adequate cardiac output. Some proposed suction detection algorithms required the external implantation of sensors, which were not reliable in long-term use due to baseline drift and short lifespan. Therefore, this study presents a new suction detection system only using the LVAD intrinsic blood pump parameter (pump speed) without using any external sensor. Three feature indices are derived from the pump speed and considered as the inputs to four different classifiers to classify the pumping states as no suction or suction. The in-silico results using a combined human circulatory system and LVAD model show that the proposed method can detect ventricular suction effectively, demonstrating that it has high classification accuracy, stability, and robustness. The proposed suction detection system could be an important part in the LVAD for detecting and avoiding suction, while at the same time making the LVAD meet the cardiac output demand for the patients. It could also provide theoretical basis and technology support for designing and optimizing the control system of the LVAD.
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.
ObjectiveTo compare the clinical efficacy of left ventricular wire pacing with traditional right ventricular lead pacing in transcatheter aortic valve replacement. MethodsPerioperative data of patients undergoing transcatheter aortic valve replacement at the Second Hospital of Hebei Medical University from January 2022 to June 2023 were collected. Patients were divided into a left ventricular wire pacing group and a right ventricular lead pacing group based on the pacing method during the procedure, and the clinical data of the two groups were compared and analyzed. ResultsA total of 102 patients were included, with 35 patients in the left ventricular wire pacing group [20 males and 15 females, age (69.2±3.1) years] and 67 patients in the right ventricular lead pacing group [37 males and 30 females, age (70.2±3.7) years]. The hemodynamic characteristics of both groups (peak flow velocity, peak transvalve pressure difference, left ventricular ejection fraction) showed significant improvement post-operation compared to pre-operation (P<0.05). There was no statistically significant difference between the two groups in terms of pacing success rate and surgical complications (P>0.05). Compared to the right ventricular lead pacing group, the left ventricular wire pacing group had shorter operation time [(76.3±17.2) min vs. (86.1±15.3) min, P=0.004] and X-ray exposure time [(18.2±6.1) min vs. (26.2±4.3) min, P<0.001], and lower total hospitalization cost [(213±28) thousand yuan vs. (262±25) thousand yuan, P<0.001]. ConclusionThe safety and reliability of left ventricular wire pacing in transcatheter aortic valve replacement are similar to those of traditional right ventricular lead pacing. Moreover, it can significantly reduce the operation and X-ray exposure time and decrease the total clinical hospitalization cost, making it a viable alternative to traditional right ventricular lead pacing.
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 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.