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Intra-aortic balloon pump (IABP) use during CPR has been scarcely studied. Intra-caval balloon pump (ICBP) may decrease backward venous flow during CPR. Mechanical chest compressions (MCC) were initiated after 10 min of cardiac arrest in anesthetized pigs. After 5 min of MCC, IABP (n = 6) or ICBP (n = 6) was initiated. The MCC device and the IABP/ICBP had slightly different frequencies, inducing a progressive peak pressure phase shift. IABP inflation 0.15 s before MCC significantly increased mean arterial pressure (MAP) and carotid blood flow (CBF) compared to inflation 0.10 s after MCC and to MCC only. Coronary perfusion pressure significantly increased with IABP inflation 0.25 s before MCC compared to inflation at MCC. ICBP inflation before MCC significantly increased MAP and CBF compared to inflation after MCC but not compared to MCC only. This shows the potential of IABP in CPR when optimally synchronized with MCC. The effect of timing of intra-aortic balloon pump (IABP) inflation during mechanical chest compressions (MCC) on hemodynamics. Data from12 anesthetized pigs. [ABSTRACT FROM AUTHOR]

Balloon pumps are employed to assist cardiac function in cases of acute myocardial infarction, ventricular arrhythmias, cardiogenic shock, unstable angina, refractory ventricular failure, or cardiac surgery. Counterpulsation, through increasing the diastolic pressure and reducing the systolic pressure, increases coronary perfusion and assists the heart to pump more blood at each contraction. An expanding-contracting balloon, modifying the Poiseuille flow in a straight circular duct, is examined in this study. The balloon is spheroid-shaped, with the length of its minor axis, which is perpendicular to the flow direction, changing in time following a sinusoidal law. The inlet flow volume rate is steady while the rate that the fluid volume leaves the duct varies in time due to the presence of the balloon. For a pulsation frequency of 60 pulses/min, the pressure difference across the pulsating balloon exhibits significant phase lagging behind the outflow volume waveform. The outlet pressure depends on the balloon radius oscillation amplitude and is computed for a range of such. The flow field around the spheroid, periodically expanding-contracting balloon in the steady flow stream is presented, in which the exact pattern of the gradual downstream intensification of the flow pulsation alongside the spheroid body is also identified. [ABSTRACT FROM AUTHOR]

The number of indications for intra-aortic balloon pumps has increased and now includes patients with a variety of conditions requiring critical care. Nurses play a key role in the care of these patients, so this scoping review aimed to identify and describe the various aspects of this role. A total of 10 articles were included, highlighting the involvement of nursing care throughout the process, from preparation for insertion to weaning. Nurses are particularly instrumental in identifying and preventing complications, which involves monitoring the patient's haemodynamic, respiratory, renal, gastrointestinal and vascular status, as well infection control measures. The extent and complexity of these nursing tasks highlights the importance of specialist training for nurses. [ABSTRACT FROM AUTHOR]

Although heart transplant is the preferred solution for patients suffering from heart failures, cardiac assist devices remain key substitute therapies. Among them, aortic augmentation using dielectric elastomer actuators (DEAs) might be an alternative technological application for the future. The electrically driven actuator does not require bulky pneumatic elements (such as conventional intra‐aortic balloon pumps) and conforms tightly to the aorta thanks to the manufacturing method presented here. In this study, the proposed DEA‐based device replaces a section of the aorta and acts as a counterpulsation device. The feasibility and validation of in vivo implantation of the device into the descending aorta in a porcine model, and the level of support provided to the heart are investigated. Additionally, the influence of the activation profile and delay compared to the start of systole is studied. We demonstrate that an activation of the DEA just before the start of systole (30 ms at 100 bpm) and deactivation just after the start of diastole (0–30 ms) leads to an optimal assistance of the heart with a maximum energy provided by the DEA. The end‐diastolic and left ventricular pressures were lowered by up to 5% and 1%, respectively, compared to baseline. The early diastolic pressure was augmented in average by up to 2%. [ABSTRACT FROM AUTHOR]

Intravascular ventricular assist system (iVAS) is an investigative device in clinical trials for the management of advanced heart failure. It works on the principle of counterpulsation, similar to the classic intra-aortic balloon counterpulsation (IABP). We present a case of a 66-year-old man with iVAS in situ who required emergency laparotomy for a strangulated umbilical hernia. Patients with mechanical circulatory devices (MCD) are presenting more frequently for emergency and even elective noncardiac operations. Managing such patients poses significant challenges to the perioperative team due to its novelty and paucity of management recommendations.

Abstract Although heart transplant is the preferred solution for patients suffering from heart failures, cardiac assist devices remain key substitute therapies. Among them, aortic augmentation using dielectric elastomer actuators (DEAs) might be an alternative technological application for the future. The electrically driven actuator does not require bulky pneumatic elements (such as conventional intra‐aortic balloon pumps) and conforms tightly to the aorta thanks to the manufacturing method presented here. In this study, the proposed DEA‐based device replaces a section of the aorta and acts as a counterpulsation device. The feasibility and validation of in vivo implantation of the device into the descending aorta in a porcine model, and the level of support provided to the heart are investigated. Additionally, the influence of the activation profile and delay compared to the start of systole is studied. We demonstrate that an activation of the DEA just before the start of systole (30 ms at 100 bpm) and deactivation just after the start of diastole (0–30 ms) leads to an optimal assistance of the heart with a maximum energy provided by the DEA. The end‐diastolic and left ventricular pressures were lowered by up to 5% and 1%, respectively, compared to baseline. The early diastolic pressure was augmented in average by up to 2%.

BACKGROUND AND PURPOSE: External counterpulsation improves cerebral perfusion velocity in acute stroke and may stimulate collateral artery growth. However, whether (non-acute) at-risk patients with high-grade carotid artery disease may benefit from counterpulsation needs to be validated. METHODS: Twenty-eight patients (71 ± 6.5 years, five women) with asymptomatic unilateral chronic severe internal carotid artery stenosis (>70%) or occlusion were randomized to receive 20 min active counterpulsation followed by sham treatment or vice versa. Cerebral blood flow velocity (CBFV) (measured bilaterally by transcranial middle cerebral artery Doppler), tissue oxygenation index (TOI) (measured over the bilateral prefrontal cortex by near-infrared spectroscopy) and cerebral hemodynamic parameters, such as relative pulse slope index (RPSI), were monitored. RESULTS: Ipsilateral mean CBFV (ΔVmean +3.5 ± 1.2 cm/s) and tissue oxygenation (ΔTOI +2.86 ± 0.8) increased significantly during active counterpulsation compared to baseline, whilst the sham had little effect (ΔVmean +1.13 ± 1.1 cm/s; ΔTOI +1.25 ± 0.65). On contralateral sides, neither counterpulsation nor sham control had any effect on either parameter. During counterpulsation, early dynamic changes in ΔRPSI of the ipsilateral CBFV signal predicted improved tissue oxygenation during counterpulsation (odds ratio 1.179, 95% confidence interval 1.01-1.51), whilst baseline cerebrovascular reactivity to hypercapnia failed to show an association. CONCLUSIONS: In patients with high-grade carotid disease, ipsilateral cerebral oxygenation and blood flow velocity are increased by counterpulsation. This is a necessary condition for the stimulation of regenerative collateral artery growth and thus a therapeutic concept for the prevention of cerebral ischaemia. This study provides a rationale for further clinical investigations on the long-term effects of counterpulsation on cerebral hemodynamics and collateral growth.

BACKGROUND: Some patients require intra-aortic balloon pump (IABP) after coronary artery bypass graft (CABG) surgery. IABP can be adjusted to different frequencies such as 1:1, 1:2, or 1:3. In this study, we tried to compare the effect of 1:1 and 1:2 frequencies of IABP on hemodynamic status of the patients after CABG surgery. METHODS: In this experimental study, all patients using IABP after CABG surgery were entered the study as pretest and posttest groups. The study could not be blinded because of the clearness of posttest group for the same echocardiographist. The pretest group included patients using a 1:1 frequency of IABP device. The posttest group included patients in the pretest group who were exposed to a 1:2 frequency for 20 minutes. In both groups, on the moderate dose of inotropic support, hemodynamic parameters of patients including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), cardiac index (CI), stroke volume (SV), and velocity time integral (VTI) in the aorta during systole were measured. Both groups were compared using Wilcoxon signed rank test. SPSS software was used for analysis and P < 0.05 was considered to be statistically significant. RESULTS: Twelve patients were entered into the study. Three patients were excluded because of open chest and instability of vital signs. Nine patients completed the study. 3 patients were men and 6 were women. The mean age was 58.32 ± 13.18 years. MAP in 1:1 frequency was significantly higher than 1:2 (P = 0.043); however, there was no significant difference between 1:1 and 1:2 in other hemodynamic parameters, namely CO, CI, SV, HR, and VTI. CONCLUSION: In patients on moderate dose of inotropes, IABP frequencies of 1:1 and 1:2 have the same effect on hemodynamic parameters such as CI, SBP, DBP, HR, and left ventricular outflow tract (LVOT) VTI; meanwhile, MAP remains higher in 1:1 frequency. [ABSTRACT FROM AUTHOR]

Intravascular ventricular assist system (iVAS) is an investigative device in clinical trials for the management of advanced heart failure. It works on the principle of counterpulsation, similar to the classic intra-aortic balloon counterpulsation (IABP). We present a case of a 66-year-old man with iVAS in situ who required emergency laparotomy for a strangulated umbilical hernia. Patients with mechanical circulatory devices (MCD) are presenting more frequently for emergency and even elective noncardiac operations. Managing such patients poses significant challenges to the perioperative team due to its novelty and paucity of management recommendations. [ABSTRACT FROM AUTHOR]

Despite being responsible for half of heart failure-related hospitalizations, heart failure with preserved ejection fraction (HFpEF) has limited evidence-based treatment options. Currently, a substantial clinical issue is that the disease etiology is very heterogenous with no patient-specific treatment options. Modeling can provide a framework for evaluating alternative treatment strategies. Counterpulsation strategies have the capacity to improve left ventricular diastolic filling by reducing systolic blood pressure and augmenting the diastolic pressure that drives coronary perfusion. Here, we propose a framework for testing the effectiveness of a soft robotic extra-aortic counterpulsation strategy using a patient-specific closed-loop hemodynamic lumped parameter model of a patient with HFpEF. The soft robotic device prototype was characterized experimentally in a physiologically pressurized (50–150 mmHg) soft silicone vessel and modeled as a combination of a pressure source and a capacitance. The patient-specific model was created using open-source software and validated against hemodynamics obtained by imaging of a patient (male, 87 years, HR = 60 bpm) with HFpEF. The impact of actuation timing on the flows and pressures as well as systolic function was analyzed. Good agreement between the patient-specific model and patient data was achieved with relative errors below 5% in all categories except for the diastolic aortic root pressure and the end systolic volume. The most effective reduction in systolic pressure compared to baseline (147 vs. 141 mmHg) was achieved when actuating 350 ms before systole. In this case, flow splits were preserved, and cardiac output was increased (5.17 vs. 5.34 L/min), resulting in increased blood flow to the coronaries (0.15 vs. 0.16 L/min). Both arterial elastance (0.77 vs. 0.74 mmHg/mL) and stroke work (11.8 vs. 10.6 kJ) were decreased compared to baseline, however left atrial pressure increased (11.2 vs. 11.5 mmHg). A higher actuation pressure is associated with higher systolic pressure reduction and slightly higher coronary flow. The soft robotic device prototype achieves reduced systolic pressure, reduced stroke work, slightly increased coronary perfusion, but increased left atrial pressures in HFpEF patients. In future work, the framework could include additional physiological mechanisms, a larger patient cohort with HFpEF, and testing against clinically used devices.

Balloon pumps are employed to assist cardiac function in cases of acute myocardial infarction, ventricular arrhythmias, cardiogenic shock, unstable angina, refractory ventricular failure, or cardiac surgery. Counterpulsation, through increasing the diastolic pressure and reducing the systolic pressure, increases coronary perfusion and assists the heart to pump more blood at each contraction. An expanding-contracting balloon, modifying the Poiseuille flow in a straight circular duct, is examined in this study. The balloon is spheroid-shaped, with the length of its minor axis, which is perpendicular to the flow direction, changing in time following a sinusoidal law. The inlet flow volume rate is steady while the rate that the fluid volume leaves the duct varies in time due to the presence of the balloon. For a pulsation frequency of 60 pulses/min, the pressure difference across the pulsating balloon exhibits significant phase lagging behind the outflow volume waveform. The outlet pressure depends on the balloon radius oscillation amplitude and is computed for a range of such. The flow field around the spheroid, periodically expanding-contracting balloon in the steady flow stream is presented, in which the exact pattern of the gradual downstream intensification of the flow pulsation alongside the spheroid body is also identified.

BackgroundExternal counterpulsation (ECP) increases perfusion to a variety of organs and may be helpful for acute stroke.MethodsWe conducted a single-blinded, prospective, randomized controlled feasibility and safety trial of ECP for acute middle cerebral artery (MCA) ischemic stroke. Twenty-three patients presenting within 48 hours of symptom onset were randomized into one of two groups. One group was treated with ECP for 1 hour at a pressure of up to 300 mmHg ("full pressure"). During the procedure, we also determined the highest possible pressure that would augment MCA mean flow velocity (MFV) by 15%. The other group was treated with ECP at 75 mmHg ("sham pressure"). Transcranial Doppler MCA flow velocities and National Institutes of Health Stroke Scale (NIHSS) scores of both groups were checked before, during, and after ECP. Outcomes were assessed at 30 days after randomization.ResultsAlthough the procedures were feasible to implement, there was a frequent inability to augment MFV by 15% despite maximal pressures in full-pressure patients. In sham-pressure patients, however, MFV frequently increased as shown by increases in peak systolic velocity and end diastolic velocity. In both groups, starting ECP was often associated with contemporaneous improvements in NIHSS stroke scores. There were no between-group differences in NIHSS, modified Rankin Scale Scores, and Barthel Indices, and no device or treatment-related serious adverse events, deaths, intracerebral hemorrhages, or episodes of acute neuro-worsening.ConclusionsECP was safe and feasible to use in patients with acute ischemic stroke. It was associated with unexpected effects on flow velocity, and contemporaneous improvements in NIHSS score regardless of pressure used, with a possibility that even very low ECP pressures had an effect. Further study is warranted.

Aim: to develop a new modified index for the assessment of bioenergy heart in conditions of heart failure. To assess the energy of the heart when using systems to bypass the left ventricle of the heart using non-pulsed flow pumps. To consider the fundamental advantage of non-pulsating flow pumps with the generation of a pulsating flow in the cardio-synchronized copulsation mode over the counterpulsation mode.

Purpose: To investigate the short-term efficacy of enhanced external counterpulsation (EECP) on chronic insomnia., Methods: This is a pilot randomized, participant-blind, and sham-controlled study. Forty-six participants with chronic insomnia were randomly assigned in a 1:1 ratio to receive EECP or sham EECP intervention (total of 35 sessions with 45 min each). The primary outcome was Pittsburgh Sleep Quality Index (PSQI). The secondary outcomes included sleep diary, Hospital Anxiety and Depression Scale (HADS), Short-Form Health Survey (SF12), flow mediated dilation (FMD), serum biomarkers of melatonin, cortisol, interleukin-6, and high sensitivity C-reactive protein. Outcomes were assessed after treatment and at 3-month follow-up., Results: The PSQI was significantly decreased in both EECP and sham groups after 35-session intervention (13.74 to 6.96 in EECP and 13.04 to 9.48 in sham), and EECP decreased PSQI more than sham EECP (p = 0.009). PSQI in two groups kept improved at 3-month follow-up. After treatment, the total sleep time, sleep efficiency, FMD value and SF12 mental component of EECP group were significantly improved, and group differences were found for these outcomes. At follow-up, total sleep time, sleep efficiency and SF12 mental component of EECP group remained improved, and group difference for SF12 mental component was found. Post-treatment and follow-up HADS-A significantly decreased in both groups, with no differences between groups. Post-treatment serum biomarkers showed no differences within and between groups., Limitation: Lack of objective sleep measurement., Conclusion: EECP could improve sleep quality and mental quality of life in chronic insomnia and the therapeutic effect maintained for 3 months., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Conventional long-term ventricular assist devices continue to be extremely problematic due to infections caused by percutaneous drivelines and thrombotic events associated with the use of blood-contacting surfaces. Here we describe a muscle-powered cardiac assist device that avoids both these problems by using an internal muscle energy converter to drive a non-blood-contacting extra-aortic balloon pump. The technology was developed previously in this lab and operates by converting the contractile energy of the latissimus dorsi muscle into hydraulic power that can be used, in principle, to drive any blood pump amenable to pulsatile actuation. The two main advantages of this implantable power source are that it 1) significantly reduces infection risk by avoiding a constant skin wound, and 2) improves patient quality-of-life by eliminating all external hardware components. The counterpulsatile balloon pumps, which compress the external surface of the ascending aorta during the diastolic phase of the cardiac cycle, offer another critical advantage in the setting of long-term circulatory support in that they increase cardiac output and improve coronary perfusion without touching the blood. The goal of this work is to combine these two technologies into a single circulatory support system that eliminates driveline complications and avoids surface-mediated thromboembolic events, thereby providing a safe, tether-free means to support the failing heart over extended – or even indefinite – periods of time. [ABSTRACT FROM AUTHOR]

As the incidence of heart failure increases, an organ shortage for cardiac transplant worsens. There has been development of both short and long-term mechanical circulatory devices for this population, each with unique advantages and different adverse event profiles. The long-term devices provide excellent mechanical circulatory support but are associated with significant morbidity. The intravascular ventricular assist system (iVAS) is a minimally invasive, ambulatory, counterpulsation heart assist system developed to provide long-term support for patients with advanced heart failure while avoiding the surgical trauma of a left ventricular assist device and minimizing the risks of infection and hemocompatibility-related adverse events. Initial experience with the iVAS shows promising evidence for its use as a long-term mechanical circulatory support device. [ABSTRACT FROM AUTHOR]

Objectives: We propose an evolution of a dielectric elastomer actuator-based cardiac assist device that acts as a counterpulsation system. We introduce a new pre-stretched actuator and implant the device in a graft bypass between the ascending and descending aorta to redirect all blood through the device (ascending aorta clamped). The objective was to evaluate the influence of these changes on the assistance provided to the heart., Methods: The novel para-aortic device and the new implantation technique were tested in vivo in 5 pigs. We monitored the pressure and flow in the aorta as well as the pressure-volume characteristics of the left ventricle. Different activation timings were tested to identify the optimal device actuation., Results: The proposed device helps reducing the end-diastolic pressure in the aorta by up to 13 ± 4.0% as well as the peak systolic pressure by up to 16 ± 3.6%. The early diastolic pressure was also increased up to 10 ± 3.5%. With different activation, we also showed that the device could increase or decrease the stroke volume., Conclusions: The new setup and the novel para-aortic device presented here helped improve cardiac assistance compared to previous studies. Moreover, we revealed a new way to assist the heart by actuating the device at different starting time to modify the left ventricular stroke volume and stroke work., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.)

Competing Interests: Declaration of competing interest The authors have no competing interests to declare.

Angina and nonobstructive coronary artery disease (ANOCA) is associated with poor outcomes and limited treatment options. Enhanced external counterpulsation (EECP) is a noninvasive treatment that involves applying external inflatable cuffs to the lower extremities to increase blood flow during diastole, followed by deflation during systole. Although EECP is approved for treatment in patients with refractory angina due to obstructive coronary artery disease, its effectiveness in treating patients with ANOCA with refractory angina is limited to small studies. We assessed the efficacy of EECP treatment in patients with ANOCA (defined as ≤50% stenosis in any major epicardial vessels) with refractory anginaby measuring changes in Canadian Cardiovascular Society (CCS) angina class, 6-minute walk test, Duke Activity Status Index (DASI), Seattle Angina Questionnaire 7 (SAQ7), and weekly anginal episodes pre-EECP and post-EECP treatment. A total of 101 patients with ANOCA with CCS class III/IV angina completed a full course of EECP treatment at 2 large EECP centers. In 101 patients with ANOCA the mean age (SD) of 60.6 (11.3) years and 62.4% of the cohort were women. We found significant improvements post-EECP treatment in CCS angina class (mean (SD) 3.4 (0.5) to 2.4 (2.9), p <0.001), 6-minute walk test (median 1200 (IQR 972 to 1411) to 1358 (1170 to 1600), p <0.001), DASI (mean (SD) 15.2 (11.6) to 31.5 (16.3), p <0.001), SAQ7 (mean (DS) 36.2 (24.7) to 31.5 (16.3), p <0.001), and weekly anginal episodes (mean (SD) 5.3 (3.5) to 2.4 (2.9), p <0.001). After EECP treatment, 71 patients (70.3%) had an improvement of ≥1 CCS angina class, including 33 (32.7%) patients improving by ≥2 CCS classes. In conclusion, in patients with ANOCA, EECP therapy reduces CCS angina class and improves exercise tolerance and capacity; and should be considered a part of optimal medical therapy., Competing Interests: Declaration of Competing Interest Dr. Quesada reports financial support from the National Institutes of Health. The remaining authors have no competing interest to declare., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: Endothelial function may improve with enhanced external counterpulsation (EECP) or acupuncture. This study aimed to evaluate the feasibility of acupoint stimulation combined with EECP (acupoint-EECP) for endothelial cell function in patients with essential hypertension., Methods: Thirty essential hypertensive patients were, randomly divided into two groups, with 15 patients in the acupoint-EECP group, and 15 patients in the control group, of which 3 cases were lost by week 6. Both groups were treated with continued medicine. The participants in the acupoint-EECP group received acupoint stimulation combined with EECP therapy, 45 min for each time, 5 times weekly for 6 weeks for a total of 22.5 hours. The selected acupoints are Zusanli (ST36), Fenglong (ST40) and Sanyinjiao (SP6). The curative effects of the two groups were compared., Results: The acupoint-EECP group (n=15) showed significant improvement in endothelial function [nitric oxide (NO) ，endothelin-1 (ET-1) and carotid-femoral pulse wave velocity (cf-PWV), respectively] values compared to the control group (n=12). Multiple imputation (n = 20 imputations) was performed to account for potential bias due to missing data. In stratified analyses, SBP and DBP values decreased when the baseline SBP was ≥120 mmHg and DBP was ≥80 mmHg., Conclusions: These findings suggest the feasibility of acupoint-EECP in improving endothelial function and treating hypertension. (The Chinese clinical trial registration number is ChiCTR2100053795.).

Objectives: To investigates the outcomes of enhanced external counterpulsation (EECP) among coronary microvascular disease (CMD) patients., Methods: Coronary microvascular disease patients were separated into the EECP (n=41) and control cohorts (n=42). Prior to and following the 4-week EECP program, coronary flow reserve (CFR) was recorded using transthoracic Doppler echocardiography. The serum endothelial nitric oxide synthase (eNOS) and endothelin-1 (ET-1) contents were analyzed by ELISA. Quality of life (QoL) was assessed by the Seattle Angina Questionnaire (SAQ) and the Canadian Cardiovascular Society (CCS) angina class., Results: After four weeks, CFR was substantially enhanced in the EECP versus control cohort ( p <0.05). Endothelin-1 was strongly diminished whereas eNOS was considerably upregulated in the EECP cohort. EECP also enhanced patients' SAQ scores and decreased the CCS angina class., Conclusion: Enhanced external counterpulsation may improve CFR and enhance the CMD patient QoL., (Copyright: © Saudi Medical Journal.)

Enhanced external counterpulsation (EECP) treatment for cerebral ischemic stroke patients with differing severity of stenosis, is subject to uncertainties due to the varying effects of the cerebral autoregulation mechanism on haemodynamics. The current study reports the development of a cerebral multi-autoregulation (MR) mathematical model, based on cerebral arteriole regulation of neurogenic, vascular smooth muscle reflex and shear stress mechanisms which takes into account the severity of stenosis. The model was evaluated by comparison to authentic clinical measurements of cerebral autoregulatory efficiency. Then it was applied to a 0D/3D geometric multi-scale haemodynamic model of a cerebral artery. Haemodynamic indicators were calculated under different pressurization durations of EECP to evaluate the efficacy for different stenosis lesions. Moderate stenosis of 50% to 60% produced excessive time-averaged wall shear stress in the distal area of the stenosis (>7 Pa) during prolonged pressurization and may result in damage to vascular endothelial cells. However, prolonged pressurization did not result in haemodynamic risk for severe stenosis of 70% to 80%, indicating that the duration of pressurization may be extended with increasing severity of stenosis. The current MR model accurately simulated cerebral blood flow and has relevance to the simulation of cerebral haemodynamics in a clinical setting., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: This study aimed to assess heart rate (HR) and metabolic responses to running when foot strikes are timed to occur exclusively during 1) the systolic phase of the cardiac cycle or 2) the diastolic phase. Methods: Ten elite male distance runners performed a testing session on a treadmill at 4.72 m⋅s -1 while matching their steps to an auditory tone and wearing a chest strap that transmitted accelerometer and ECG signals. Testing comprised eight prompted 3-min stages, where a real-time adaptive auditory tone guided subjects to step with each ECG R-wave (systolic stepping) or alternatively, at 45% of each R-R interval (diastolic stepping), followed by a 3-min unprompted control stage. Metabolic variables were measured continuously. Results: HR (P < 0.001) and minute ventilation (P < 0.001) were significantly lower during diastolic stepping compared with systolic stepping, whereas O2 pulse (P < 0.001) was correspondingly significantly higher during diastolic stepping. Conclusion: Synchronizing foot strikes when running to the diastolic portion of the cardiac cycle results in a significantly reduced HR and minute ventilation compared with stepping during systole. This cardiac and ventilatory response to diastolic stepping may be beneficial to distance running performance. [ABSTRACT FROM AUTHOR]

Mechanical circulatory support plays an increasing role in the management of patients with cardiac failure. Of the several forms to be discussed, intra-aortic balloon pump (IABP) counterpulsation is the most widely utilized. This involves percutaneous insertion of a balloon catheter through the femoral artery that inflates during diastole and deflates prior to systole, improving ventricular performance by simultaneously increasing myocardial oxygen supply during diastole and reducing myocardial oxygen demand by reducing afterload. Other forms of more advanced mechanical circulatory support that will be discussed include extracorporeal membrane oxygenation, ventricular assist devices and the total artificial heart. These technologies can replace rather than simply support cardiac function, as in the case of the IABP, and as such patient selection is critical. The use of these technologies must be balanced against potential complications which can be significant. [ABSTRACT FROM AUTHOR]

Background The intravascular ventricular assist system (iVAS) is a new, minimally invasive, ambulatory counterpulsation heart assist system delivered via the subclavian artery and powered by a portable driver. It is designed for recovery, bridge to transplantation (BTT) or for prolonging medical therapy. We report the first-in-human (FIH) experience with iVAS. Methods This is a prospective, non-randomized single arm, U.S. Food and Drug Administration (FDA)-approved early feasibility trial in patients listed for cardiac transplantation. The primary end-point was survival to transplant or stroke-free survival at 30 days. Results Fourteen patients were enrolled and 13 (92.8%) were treated with iVAS. At time of implant, the average age was 58 ± 6.7 years; 85% were male; 28% had ischemic cardiomyopathy; and 3 were Interagency Registry for Mechanically Assisted Devices (INTERMACS) Level 2, 9 were Level 3, and 1 was Level 4. The mean left ventricular ejection fraction was 22%, left ventricular internal diameter diastole was 7.13 mm, and 69% had moderate or severe mitral regurgitation. There were no intra-operative complications. Intensive care unit stay after implant was 6 ± 6 days. All patients were transplanted after 32 ± 21 days. There were no deaths or thromboembolic events: 1 patient required escalation of mechanical support, and post-implant complications included pleuritis/pericarditis ( n = 1) and neuropathy ( n = 2). No intra-operative blood transfusions were required. Conclusions This study demonstrates a high rate of successful outcomes with an excellent risk-to-benefit profile. This FIH experience reveals that the iVAS can be successfully inserted in a standardized approach, provide hemodynamic support, can be interrupted for short periods, and allows for ambulation. A multicenter trial to investigate effectiveness and safety is warranted. [ABSTRACT FROM AUTHOR]

Background: Enhanced external counterpulsation (EECP) reduces angina pectoris, extends time to exercise-induced ischemia, and improves quality of life in patients with symptomatic stable angina. We aimed to evaluate the effects of EECP on heart rate recovery in patients with coronary artery disease (CAD). Methods: Between January 2011 and March 2013, a total of 34 consecutive patients (24 male, 70.6%) with symptomatic CAD, who were candidated for EECP, prospectively received 35 sessions of 1-hour EECP therapy per day, 6 days per week. The patients underwent echocardiography and a symptom-limited modified Bruce exercise test before and after EECP. Left ventricular ejection fraction (LVEF), resting and peak exercise heart rates, systolic blood pressure, heart rate at 1 and 2 minutes of recovery, exercise duration, workload, and first- and second-minute heart rate recovery were measured before EECP and compared with those after EECP. Results: The mean age of the patients (70.6% men) was 64.82 ± 8.28 years. After EECP, exercise duration increased significantly from 6.48 ± 2.76 minutes to 9.20 ± 2.71 minutes (p value < 0.001). Maximum workload increased significantly (4.44 ± 1.28 vs. 5.65 ± 1.77 METS; p value < 0.001). The LVEF increased from 42.65 ± 11.82% to 44.26 ± 11.86% (p value < 0.001). The resting systolic blood pressure decreased significantly from 125.59 ± 22.35 mmHg to 116.26 ± 14.93 mmHg (p value = 0.013). The increase in the first- and second-minute heart rate recovery after EECP was not statistically significant. Conclusion: The results of the present study showed that exercise duration, maximum workload, and the LVEF might increase significantly after EECP. The increase in the first- and second-minute heart rate recovery after EECP was not statistically significant. [ABSTRACT FROM AUTHOR]

In this paper, we present a review of the intra-aortic balloon pump, as well as the usage of it in the medical field today. An intra-aortic balloon pump (IABP) is a biomedical device that can assist the heart during unstable angina or after a heart attack. This pump is typically used in patients who suffer from ischemia of the heart tissue, due to an unbalanced level of myocardial oxygen supply or demand. Through counterpulsation, which is a technique to synchronize the external pumping of blood with the heart’s cycle, the device can balance the supply and demand of blood that is necessary for the heart to pump properly. The IABP is comprised of the following four components: a polyurethane balloon, a polyethylene or fiber-optic catheter, a transducer, and the intra-aortic balloon pump console. In the past, researchers have used other materials that have low biocompatibility and can cause complications within the body. This analysis will explain the complications and state changes that occurred due to them. Limitations of past designs and advantages of current designs will be acknowledged, for they can be used by researchers to enhance designs for the future. Consequently, the analysis of this device may lead to improved designs and treatment in the future for patients with cardiac conditions.

Aim Physical activity is a potent way to impede vascular ageing. However, patients who suffer from peripheral artery disease ( PAD) are often unable to exercise adequately. For those patients, we have developed individual shear rate therapy ( ISRT), which is an adaptation of external counterpulsation and enhances endovascular fluid shear stress to increase collateral growth (arteriogenesis). To evaluate the effects of physical exercise and ISRT on the telomere biology of peripheral blood mononuclear cells ( PBMCs), we conducted two clinical trials. Methods In the ISRT-1 study, we assessed PBMC telomerase activity in 26 young healthy volunteers upon a single (short-term) ISRT session and a single treadmill running session. In the ISRT-2 study, we investigated PBMC telomere biology of 14 elderly patients with PAD, who underwent 30 h of (long-term) ISRT within a 5-week period. Results We demonstrate that telomerase activity significantly increased from 39.84 Total Product Generated ( TPG) Units ± 6.15 to 58.10 TPG ± 10.46 upon a single treadmill running session in healthy volunteers. In the ISRT-2 trial, PBMC telomerase activity and the mRNA expression of the telomere-protective factor TRF2 increased from 40.87 TPG ± 4.45 to 60.98 TPG ± 6.83 and 2.10-fold ± 0.40, respectively, upon long-term ISRT in elderly patients with PAD. Conclusion In summary, we show that acute exercise and long-term ISRT positively affect PBMC telomerase activity, which is indicative for an improved regenerative potential of immune cells and vascular tissues. Long-term ISRT also enhances the gene expression of the telomere-protective factor TRF2. [ABSTRACT FROM AUTHOR]

Mechanical circulatory support devices (MCSDs) have gained widespread clinical acceptance as an effective heart failure (HF) therapy. The concept of harnessing the kinetic energy (KE) available in the forward aortic flow (AOF) is proposed as a novel control strategy to further increase the cardiac output (CO) provided by MCSDs. A complete mathematical development of the proposed theory and its application to an example MCSDs (two-segment extra-aortic cuff) are presented. To achieve improved device performance and physiologic benefit, the example MCSD timing is regulated to maximize the forward AOF KE and minimize retrograde flow. The proof-of-concept was tested to provide support with and without KE control in a computational HF model over a wide range of HF test conditions. The simulation predicted increased stroke volume (SV) by 20% (9 mL), CO by 23% (0.50 L/min), left ventricle ejection fraction (LVEF) by 23%, and diastolic coronary artery flow (CAF) by 55% (3 mL) in severe HF at a heart rate (HR) of 60 beats per minute (BPM) during counterpulsation (CP) support with KE control. The proposed KE control concept may improve performance of other MCSDs to further enhance their potential clinical benefits, which warrants further investigation. The next step is to investigate various assist technologies and determine where this concept is best applied. Then bench-test the combination of kinetic energy optimization and its associated technology choice and finally test the combination in animals. [ABSTRACT FROM AUTHOR]