Modeling and control of an implantable rotary blood pump for heart failure patients

Background: During decompensated heart failure, the use of intravenous inotropes can be necessary. With peripheral venous access, prolonged inotrope infusion can cause phlebitis. However, traditional central venous catheters have possible complications. Peripherally inserted central catheters (PICCs) may be an alternative to traditional catheters. Aim: Our objective was to compare the incidence of phlebitis between patients with PICC and those with peripheral venous access catheter indwelling. Methods: In a randomized clinical trial, the patients were randomized to PICC and control groups, with 40 patients in each group. The inclusion criteria were hospitalized patients with advanced heart failure, ejection fraction of <0.45, and platelet count of >50,000/mm3 and current use of continuous intravenous infusion of dobutamine. The patients were randomly assigned to receive a PICC or keep their peripheral venous access. The primary end point was the occurrence of phlebitis. Results: The PICC and control groups included 40 patients each. The median age was 61.5 years; ejection fraction, 0.24; and dobutamine dose, 7.73 µg/(kg min). Phlebitis occurred in 1 patient (2.5%) in the PICC group and in 38 patients (95.0%) in the control group, with an odds ratio of 0.10% (95% confidence interval: 0.01%–1.60%, p < 0.001). Conclusion: In conclusion, in severe heart failure patients who received intravenous dobutamine, PICC use reduced the incidence of phlebitis when compared to patients with peripheral venous access. Therefore, the PICC use should considered over peripheral venous access for prolonged intravenous therapy in heart failure patients.

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Abnormal nailfold videocapillaroscopic findings in heart failure patients with preserved ejection fraction

Clinical Hemorheology and Microcirculation ◽

10.3233/ch-200968 ◽

2020 ◽

pp. 1-7

Author(s):

Serkan Yüksel ◽

Esra Pancar Yüksel ◽

Murat Meriç

Keyword(s):

Heart Failure ◽

Ejection Fraction ◽

Control Group ◽

Preserved Ejection Fraction ◽

Control Groups ◽

Nailfold Videocapillaroscopy ◽

Heart Failure Patients ◽

Significant Difference ◽

Patients With Heart Failure ◽

And Control

BACKGROUND: Microvascular dysfunction is one of the pathophysiological mechanisms in heart failure. Nailfold videocapillaroscopy is a noninvasive technique used to examine the microvasculature. OBJECTIVE: In this study; we aimed to investigate the nailfold capillaroscopic abnormalities in heart failure patients with reduced and preserved ejection fraction and compare those with control group. METHODS: Three groups of patients were recruited for the study: HFrEF group includes the patients with heart failure with reduced ejection fraction (HFrEF), HFpEF group, patients with heart failure with preserved ejection fraction (HFpEF) and control group, healthy asymptomatic individuals. Nailfold videocapillaroscopy was performed with a videodermatoscope and all nailfold images were evaluated for enlargement and hemorrhages. RESULTS: Abnormal videocapillaroscopic findings including enlargement and/or hemorrhages were present in 7 (24%) patients in HFrEF group, 19 (66%) patients in HFpEF group and 11 (37%) in control group. The number of patients with abnormal videocapillaroscopic findings were significantly greater in HFpEF group compared to HFrEF (p < 0.05) and control groups (p < 0.05). However, no significant difference was observed in videocapillaroscopic findings between HFrEF and control groups. CONCLUSIONS: Our study showed that microvascular abnormalities demonstrated by videodermatoscopic examination of nailfold capillaries are considerably more common in HFpEF patients compared to HFrEF and control groups.

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Design and Numerical Evaluation of an Axial Partial-assist Blood Pump for Chinese and other Heart Failure Patients

The International Journal of Artificial Organs ◽

10.5301/ijao.5000616 ◽

2017 ◽

Vol 40 (9) ◽

pp. 489-497 ◽

Cited By ~ 2

Author(s):

Guang-Mao Liu ◽

Dong-Hai Jin ◽

Jian-Ye Zhou ◽

Xi-Hang Jiang ◽

Han-Song Sun ◽

...

Keyword(s):

Heart Failure ◽

Shear Stress ◽

Flow Rate ◽

Tangential Velocity ◽

Pressure Head ◽

Left Ventricular ◽

Blood Pump ◽

Partial Support ◽

Heart Failure Patients ◽

Cantilever Structure

A fully implantable axial left ventricular assist device LAP31 was developed for Chinese or other heart failure patients who need partial support. Based on the 5-Lpm total cardiac blood output of Chinese without heart failure disease, the design point of LAP31 was set to a flow rate of 3 Lpm with 100-mmHg pressure head. To achieve the required pressure head and good hemolytic performance, a structure that includes a spindly rotor hub and a diffuser with splitter and cantilevered main blades was developed. Computational fluid dynamics (CFD) was used to analyze the hydraulic and hemodynamic performance of LAP31. Then in vitro hydraulics experiments were conducted. The numerical simulation results show that LAP31 could generate a 1 to 8 Lpm flow rate with a 60.9 to 182.7 mmHg pressure head when the pump was rotating between 9,000 and 12,000 rpm. The average scalar shear stress of the blood pump was 21.7 Pa, and the average exposure time was 71.0 milliseconds. The mean hemolysis index of LAP31 obtained using Heuser's hemolysis model and Giersiepen's model was 0.220% and 3.89 × 105% respectively. After adding the splitter blades, the flow separation at the suction surface of the diffuser was reduced. The cantilever structure reduced the tangential velocity from 6.1 to 4.7–1.4 m/s within the blade gap by changing the blade gap from shroud to hub. Subsequently, the blood damage caused by shear stress was reduced. In conclusion, the hydraulic and hemolytic characteristics of the LAP31 are acceptable for partial support.

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