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Manga S, Muthavarapu N, Redij R, Baraskar B, Kaur A, Gaddam S, Gopalakrishnan K, Shinde R, Rajagopal A, Samaddar P, Damani DN, Shivaram S, Dey S, Mitra D, Roy S, Kulkarni K, Arunachalam SP. Estimation of Physiologic Pressures: Invasive and Non-Invasive Techniques, AI Models, and Future Perspectives. SENSORS (BASEL, SWITZERLAND) 2023; 23:5744. [PMID: 37420919 DOI: 10.3390/s23125744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 05/25/2023] [Accepted: 06/12/2023] [Indexed: 07/09/2023]
Abstract
The measurement of physiologic pressure helps diagnose and prevent associated health complications. From typical conventional methods to more complicated modalities, such as the estimation of intracranial pressures, numerous invasive and noninvasive tools that provide us with insight into daily physiology and aid in understanding pathology are within our grasp. Currently, our standards for estimating vital pressures, including continuous BP measurements, pulmonary capillary wedge pressures, and hepatic portal gradients, involve the use of invasive modalities. As an emerging field in medical technology, artificial intelligence (AI) has been incorporated into analyzing and predicting patterns of physiologic pressures. AI has been used to construct models that have clinical applicability both in hospital settings and at-home settings for ease of use for patients. Studies applying AI to each of these compartmental pressures were searched and shortlisted for thorough assessment and review. There are several AI-based innovations in noninvasive blood pressure estimation based on imaging, auscultation, oscillometry and wearable technology employing biosignals. The purpose of this review is to provide an in-depth assessment of the involved physiologies, prevailing methodologies and emerging technologies incorporating AI in clinical practice for each type of compartmental pressure measurement. We also bring to the forefront AI-based noninvasive estimation techniques for physiologic pressure based on microwave systems that have promising potential for clinical practice.
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Affiliation(s)
- Sharanya Manga
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Neha Muthavarapu
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Renisha Redij
- GIH Artificial Intelligence Laboratory (GAIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Avneet Kaur
- Microwave Engineering and Imaging Laboratory (MEIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Sunil Gaddam
- Microwave Engineering and Imaging Laboratory (MEIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Keerthy Gopalakrishnan
- GIH Artificial Intelligence Laboratory (GAIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Microwave Engineering and Imaging Laboratory (MEIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Rutuja Shinde
- Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Poulami Samaddar
- Microwave Engineering and Imaging Laboratory (MEIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Devanshi N Damani
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Department of Internal Medicine, Texas Tech University Health Science Center, El Paso, TX 79995, USA
| | - Suganti Shivaram
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
| | - Shuvashis Dey
- Microwave Engineering and Imaging Laboratory (MEIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Department of Electrical and Computer Engineering, North Dakota State University, Fargo, ND 58105, USA
| | - Dipankar Mitra
- Microwave Engineering and Imaging Laboratory (MEIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Department of Computer Science, University of Wisconsin-La Crosse, La Crosse, WI 54601, USA
| | - Sayan Roy
- Microwave Engineering and Imaging Laboratory (MEIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Department of Electrical Engineering and Computer Science, South Dakota Mines, Rapid City, SD 57701, USA
| | - Kanchan Kulkarni
- Centre de Recherche Cardio-Thoracique de Bordeaux, University of Bordeaux, INSERM, U1045, 33000 Bordeaux, France
- IHU Liryc, Heart Rhythm Disease Institute, Fondation Bordeaux Université, Bordeaux, 33600 Pessac, France
| | - Shivaram P Arunachalam
- GIH Artificial Intelligence Laboratory (GAIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA
- Microwave Engineering and Imaging Laboratory (MEIL), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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Costa R, Moreira E, Silva Cardoso J, Azevedo LF, Ribeiro JA, Pinto R. Effectiveness of Exercise-Based Cardiac Rehabilitation for Heart
Transplant Recipients: A Systematic Review and Meta-Analysis. Health Serv Insights 2023; 16:11786329231161482. [PMID: 36968658 PMCID: PMC10034295 DOI: 10.1177/11786329231161482] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 02/16/2023] [Indexed: 03/24/2023] Open
Abstract
Background: Heart Transplant (HTx) is the ultimate chance of life for end stage Heart
Failure (HF). Exercise training has consistently shown the potential to
improve functional capacity in various chronic heart diseases. Still, the
evidence in HTx recipients is scarcer. This study aims to systematically
review the literature to evaluate the effectiveness and safety of
Exercise-based Cardiac Rehabilitation (EBCR) in HTx recipients and to
identify possible moderators of success. Methods: We conducted a systematic review and meta-analysis of randomized controlled
trials on the effect and safety of EBCR in adult HTx recipients. The primary
outcome was functional capacity, measured by Peak Oxygen Uptake (pVO2). We
searched CENTRAL, MEDLINE, Embase, Scopus, and Web of Knowledge databases
until December 2020, reviewed references of relevant articles and contacted
experts. Usual care (UC), the different dosages of exercise regimens and
alternative settings were allowed as comparators. A quantitative synthesis
of evidence was performed using random-effects meta-analyses. Results: A total of 11 studies with 404 patients were included. Nine studies
comprising 306 patients compared EBCR with usual care. They showed that EBCR
improved pVO2 compared to usual care (Mean Difference [MD] 3.03 mL/kg/min,
95% CI [2.28-3.77]; I2 = 32%). In the subgroup
analysis, including length of intervention and timing of enrollment after
HTx, no significant moderator was found. Two trials, with 98 patients total,
compared High Intensity Interval Training (HIIT) and Moderate Intensity
Continuous Training (MICT). HIIT attained a significant edge over MICT (MD
2.23 mL/kg/min, 95% CI [1.79-2.67]; I2 = 0%). No
major adverse events associated with EBCR were reported. Conclusion: We found moderate quality evidence suggesting EBCR has a significant benefit
on functional capacity improvement HTx recipients at the short-term. HIIT
showed superiority when compared to MICT. Research focusing long term
outcomes and standardized protocols are needed to improve evidence on EBCR
effectiveness.
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Affiliation(s)
- Rúben Costa
- Faculty of Medicine, University of
Porto, Porto, Portugal
- Department of Dermatology and
Venereology, Centro Hospitalar Universitário de São João, Porto, Portugal
- Rúben Alexandre Nogueira Costa, Centre for
Health Technology and Services Research, Centro Hospitalar Universitário São
João, Rua Dr. Plácido da Costa, Porto 4200-450, Portugal.
| | - Emília Moreira
- CINTESIS, Centre for Health Technology
and Services Research, Faculty of Medicine, University of Porto, Porto,
Portugal
- RISE: Health Research Network
| | - José Silva Cardoso
- CINTESIS, Centre for Health Technology
and Services Research, Faculty of Medicine, University of Porto, Porto,
Portugal
- RISE: Health Research Network
- Department of Medicine, Faculty of
Medicine, University of Porto, Porto, Portugal
- Department of Cardiology, Centro
Hospitalar Universitário de São João, Porto, Portugal
| | - Luís Filipe Azevedo
- CINTESIS, Centre for Health Technology
and Services Research, Faculty of Medicine, University of Porto, Porto,
Portugal
- RISE: Health Research Network
- Department of Community Medicine,
Information and Health Decision Sciences, Faculty of Medicine, University of Porto,
Portugal
| | - João Alves Ribeiro
- Faculty of Engineering, University of
Porto, Porto, Portugal
- MIT Portugal Ph.D. candidate, Faculty
of Engineering, University of Porto, Porto, Portugal
| | - Roberto Pinto
- Department of Cardiology, Centro
Hospitalar Universitário de São João, Porto, Portugal
- Department of Biomedicine, Faculty of
Medicine, University of Porto, Porto, Portugal
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Impact of Exercise Modalities on Peripheral and Central Components of Cardiorespiratory Capacity in Heart Transplantation Patients: A Systematic Review and Meta-Analysis. Medicina (B Aires) 2021; 58:medicina58010032. [PMID: 35056339 PMCID: PMC8779927 DOI: 10.3390/medicina58010032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/10/2021] [Accepted: 12/24/2021] [Indexed: 11/17/2022] Open
Abstract
Background and Objectives: To analyze the effects of aerobic, resistance, and combined training on peripheral and central components related to cardiorespiratory capacity after HTx. Materials and Methods: No time restriction was applied for study inclusion. MEDLINE/PubMed; EMBASE, CENTRAL, and PEDro databases were investigated. Studies reporting heart transplanted patients older than 19 years following aerobic, resistance, and combined training according. The outcomes included: V′O2 peak, VE/V’CO2 slope, heart rate (HR peak), systolic and diastolic blood pressure (SBP and DBP peak), maximum repetition test(1RM), sit-to-stand test, and flow-mediated dilation (FMD). The studies were selected by consensus. Four hundred ninety-two studies initially met the selection criteria. Cochrane handbook was used for abstracting data and assessing data quality and validity. Independent extraction by two observers was applied. Results: Isolated aerobic training leads to a greater increase in V′O2 peak than combined training compared to the control group (p < 0.001, I2 = 0%). However, no significant differences were found in the subgroup comparison (p = 0.19, I2 = 42.1%). HR peak increased similarly after aerobic and combined training. High-intensity interval training (HIIT) was better than moderate continuous intensity to increase the V′O2 after long term in HTx. Still, there is scarce evidence of HIIT on muscle strength and FMD. No change on VE/V’CO2 slope, FMD, and SBP, DBP peak. 1RM and the sit-to-stand test increased after resistance training (p < 0.001, I2 = 70%) and CT (p < 0.001, I2 = 0%) when compared to control. Conclusions: Aerobic and combined training effectively improve VO2 peak and muscle strength, respectively. HIIT seems the better choice for cardiorespiratory capacity improvements. More studies are needed to examine the impact of training modalities on VE/V’CO2 slope and FMD.
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Comments on "Right ventricular failure in septic shock: characterization, incidence and impact on fluid responsiveness": which parameter to assess right ventricular failure and venous congestion? CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2021; 25:136. [PMID: 33836816 PMCID: PMC8034069 DOI: 10.1186/s13054-021-03473-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 01/13/2021] [Indexed: 11/21/2022]
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Haberbusch M, De Luca D, Moscato F. Changes in Resting and Exercise Hemodynamics Early After Heart Transplantation: A Simulation Perspective. Front Physiol 2020; 11:579449. [PMID: 33240102 PMCID: PMC7677526 DOI: 10.3389/fphys.2020.579449] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/30/2020] [Indexed: 11/13/2022] Open
Abstract
Introduction: During heart transplantation (HTx), cardiac denervation is inevitable, thus typically resulting in chronic resting tachycardia and chronotropic incompetence with possible consequences in patient quality of life and clinical outcomes. To this date, knowledge of hemodynamic changes early after HTx is still incomplete. This study aims at providing a model-based description of the complex hemodynamic changes at rest and during exercise in HTx recipients (HTxRs). Materials and Methods: A numerical model of early HTxRs is developed that integrates intrinsic and autonomic heart rate (HR) control into a lumped-parameter cardiovascular system model. Intrinsic HR control is realized by a single-cell sinoatrial (SA) node model. Autonomic HR control is governed by aortic baroreflex and pulmonary stretch reflex and modulates SA node activity through neurotransmitter release. The model is tuned based on published clinical data of 15 studies. Simulations of rest and exercise are performed to study hemodynamic changes associated with HTxRs. Results: Simulations of HTxRs at rest predict a substantially increased HR [93.8 vs. 69.5 beats/min (bpm)] due to vagal denervation while maintaining normal cardiac output (CO) (5.2 vs. 5.6 L/min) through a reduction in stroke volume (SV) (55.4 vs. 82 mL). Simulations of exercise predict markedly reduced peak CO (13 vs. 19.8 L/min) primarily resulting from diminished peak HRs (133.9 vs. 169 bpm) and reduced ventricular contractility. Yet, the model results show that HTxRs can maintain normal CO for low- to medium-intensity exercise by increased SV augmentation through the Frank-Starling mechanism. Conclusion: Relevant hemodynamic changes occur after HTx. Simulations suggest that (1) increased resting HRs solely result from the absence of vagal tone; (2) chronotropic incompetence is the main limiting factor of exercise capacity whereby peripheral factors play a secondary role; and (3) despite the diminished exercise capacity, HTxRs can compensate chronotropic incompetence by a preload-mediated increase in SV augmentation and thus maintain normal CO in low- to medium-intensity exercise.
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Affiliation(s)
- Max Haberbusch
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
| | - Daniela De Luca
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa, Italy
- Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Francesco Moscato
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
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Bovard JM, DE Souza AM, Harris KC, Human DG, Hosking MCK, Potts JE, Armstrong K, Sandor GGS, Cote AT. Physiological Responses to Exercise in Pediatric Heart Transplant Recipients. Med Sci Sports Exerc 2019; 51:850-857. [PMID: 30629048 DOI: 10.1249/mss.0000000000001889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Pediatric heart transplant (HTx) recipients have reduced exercise capacity typically two-thirds of predicted values, the mechanisms of which are not fully understood. We sought to assess the cardiorespiratory responses to progressive exercise in HTx relative to controls matched for age, sex, body size, and work rate. METHODS Fourteen HTx recipients and matched controls underwent exercise stress echocardiography on a semisupine cycle ergometer. Hemodynamics, left ventricular (LV) dimensions, and volumes were obtained and indexed to body surface area. Oxygen consumption (V˙O2) was measured, and arteriovenous oxygen difference was estimated using the Fick Principle. RESULTS At rest, LV mass index (P = 0.03) and volumes (P < 0.001) were significantly smaller in HTx, whereas wall thickness (P < 0.01) and LV mass-to-volume ratio (P = 0.01) were greater. Differences in LV dimensions and stroke volume persisted throughout exercise, but the pattern of response was similar between groups as HR increased. As exercise progressed, heart rate and cardiac index increased to a lesser extent in HTx. Despite this, V˙O2 was similar (P = 0.82) at equivalent work rates as HTx had a greater change in arteriovenous oxygen difference (P < 0.01). CONCLUSIONS When matched for work rate, HTx had similar metabolic responses to controls despite having smaller LV chambers and an attenuated increase in hemodynamic responses. These findings suggest that HTx may increase peripheral O2 extraction as a compensatory mechanism in response to reduced cardiovascular function.
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Affiliation(s)
- Joshua M Bovard
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, CANADA
| | - Astrid M DE Souza
- Children's Heart Centre, BC Children's Hospital, Vancouver, British Columbia, CANADA
| | - Kevin C Harris
- Children's Heart Centre, BC Children's Hospital, Vancouver, British Columbia, CANADA.,Department of Pediatrics (Cardiology), University of British Columbia, Vancouver, British Columbia, CANADA
| | - Derek G Human
- Children's Heart Centre, BC Children's Hospital, Vancouver, British Columbia, CANADA.,Department of Pediatrics (Cardiology), University of British Columbia, Vancouver, British Columbia, CANADA
| | - Martin C K Hosking
- Children's Heart Centre, BC Children's Hospital, Vancouver, British Columbia, CANADA.,Department of Pediatrics (Cardiology), University of British Columbia, Vancouver, British Columbia, CANADA
| | - James E Potts
- Children's Heart Centre, BC Children's Hospital, Vancouver, British Columbia, CANADA.,Department of Pediatrics (Cardiology), University of British Columbia, Vancouver, British Columbia, CANADA
| | - Kathryn Armstrong
- Children's Heart Centre, BC Children's Hospital, Vancouver, British Columbia, CANADA
| | - George G S Sandor
- Children's Heart Centre, BC Children's Hospital, Vancouver, British Columbia, CANADA.,Department of Pediatrics (Cardiology), University of British Columbia, Vancouver, British Columbia, CANADA
| | - Anita T Cote
- Department of Pediatrics (Cardiology), University of British Columbia, Vancouver, British Columbia, CANADA.,School of Human Kinetics, Trinity Western University, Langley, British Columbia, CANADA
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Su L, Pan P, Li D, Zhang Q, Zhou X, Long Y, Wang X, Liu D. Central Venous Pressure (CVP) Reduction Associated With Higher Cardiac Output (CO) Favors Good Prognosis of Circulatory Shock: A Single-Center, Retrospective Cohort Study. Front Med (Lausanne) 2019; 6:216. [PMID: 31681775 PMCID: PMC6803478 DOI: 10.3389/fmed.2019.00216] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 09/19/2019] [Indexed: 12/26/2022] Open
Abstract
Background: The Frank-Starling curve is the basis of hemodynamics. Changes in cardiac output (CO) caused by central venous pressure (CVP) are the most important concerns in the treatment of critically ill patients. Objectives: To explore the use of CVP and its relevant mechanisms with respect to CO in the clinic. Methods: A total of 134 patients with circulatory shock were retrospectively included and analyzed. Hemodynamic data were recorded and analyzed at PICCO initiation and 24 h after PICCO. Data regarding 28-day mortality and renal function were also collected. Results: The patients were divided into a CVP↑+ CO↑ group (n = 23), a CVP↑+ CO↓ group (n = 29), a CVP↓+ CO↑ group (n = 44), and a CVP↓+ CO↓ group (n = 38) based on values at PICCO initiation and 24 h after PICCO. Post- hoc tests showed that the CVP↓+ CO↑ group had a higher 28-day survival than the other groups [log-rank (Mantel-Cox) = 8.758, 95%, CI, 20.112–23.499, P = 0.033]. In terms of hemodynamic characteristics, the CVP↓+ CO↑ group had a lower cardiac function index (CFI) (4.1 ± 1.4/min) and higher extravascular lung water index (EVLWI) (11.0 ± 4.7 ml/kg) at PICCO initiation. This group used more cardiotonic drugs (77.3%, P < 0.001) and had a negative fluid balance (−780.4 ± 1720.6 ml/24 h, P = 0.018) 24 h after PICCO than the other three groups. Cardiotonic drug use and dehydration treatment were associated with increased CFI (from 4.1 ± 1.4 /min to 4.5 ± 1.3/min, P = 0.07) and reduced ELVWI (from 11.0 ± 4.7 ml/kg to 9.0 ± 3.5 ml/kg, P = 0.029). Renal function tests showed that SCr and BUN levels in the CVP↓+ CO↑ group were significantly improved (SCr from 197.1 ± 128.9 mmol/L to 154.4 ± 90.8 mmol/L; BUN from 14.3 μmol/L ± 7.3 to 11.6 ± 7.0 μmol/L, P < 0.05). Conclusions: Lower CVP was associated with increased CO, which may improve the 28-day prognosis in patients with circulatory shock. Notably, higher CO derived from lower CVP may also contribute to renal function improvement.
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Affiliation(s)
- Longxiang Su
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Pan Pan
- Department of Critical Care Medicine, Chinese PLA General Hospital, Beijing, China
| | - Dongkai Li
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Qing Zhang
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiang Zhou
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yun Long
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiaoting Wang
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Dawei Liu
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
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Rolid K, Andreassen AK, Yardley M, Bjørkelund E, Karason K, Wigh JP, Dall CH, Gustafsson F, Gullestad L, Nytrøen K. Clinical features and determinants of VO 2peak in de novo heart transplant recipients. World J Transplant 2018; 8:188-197. [PMID: 30211027 PMCID: PMC6134270 DOI: 10.5500/wjt.v8.i5.188] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/29/2018] [Accepted: 08/06/2018] [Indexed: 02/05/2023] Open
Abstract
AIM To study exercise capacity and determinants of early peak oxygen consumption (VO2peak) in a cohort of de novo heart transplant (HTx) recipients.
METHODS To determine possible central (chronotropic responses, cardiopulmonary and hemodynamic function) and peripheral factors (muscular exercise capacity and body composition) predictive of VO2peak, a number of different measurements and tests were performed, as follows: Cardiopulmonary exercise testing (CPET) was performed mean 11 wk after surgery in 81 HTx recipients > 18 years and was measured with breath by breath gas exchange on a treadmill or bicycle ergometer. Metabolic/respiratory measures include VO2peak and VE/VCO2 slope. Additional measures included muscle strength testing, bioelectrical impedance analysis, echocardiography, blood sampling and health-related quality of life. Based on the VO2peak (mL/kg per minute) median value, the study population was divided into two groups defined as a low-capacity group and a high-capacity group. Potential predictors were analyzed using multiple regression analysis with VO2peak (L/min) as the dependent variable.
RESULTS The mean ± standard deviation (SD) age of the total study population was 49 ± 13 years, and 73% were men. This de novo HTx cohort demonstrated a median VO2peak level of 19.4 mL/kg per min at 11 ± 1.8 wk post-HTx. As compared with the high-capacity group, the low-capacity group exercised for a shorter time, had lower maximal ventilation, O2 pulse, peak heart rate and heart rate reserve, while the VE/VCO2 slope was higher. The low-capacity group had less muscle strength and muscular exercise capacity in comparison with the high-capacity group. In order of importance, O2 pulse, heart rate reserve, muscular exercise capacity, body mass index, gender and age accounted for 84% of the variance in VO2peak (L/min). There were no minor or major serious adverse events during the CPET.
CONCLUSION Although there is great individual variance among de novo HTx recipients, early VO2peak measures appear to be influenced by both central and peripheral factors.
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Affiliation(s)
- Katrine Rolid
- Department of Cardiology, Oslo University Hospital, Oslo 0424, Norway
- the Norwegian Health Association, Oslo 0307, Norway
- Faculty of Medicine, University of Oslo, Oslo 0316, Norway
- KG Jebsen Center for Cardiac Research, and Center for Heart Failure Research, University of Oslo, Oslo 0316, Norway
| | - Arne K Andreassen
- Department of Cardiology, Oslo University Hospital, Oslo 0424, Norway
| | - Marianne Yardley
- Department of Cardiology, Oslo University Hospital, Oslo 0424, Norway
- the Norwegian Health Association, Oslo 0307, Norway
- Faculty of Medicine, University of Oslo, Oslo 0316, Norway
| | | | - Kristjan Karason
- Department of Cardiology, Sahlgrenska University Hospital, Gothenburg 41345, Sweden
| | - Julia P Wigh
- Department of Physical Therapy, Sahlgrenska University Hospital, Gothenburg 41345, Sweden
| | - Christian H Dall
- Department of Cardiology, Bispebjerg University Hospital, Copenhagen 2400, Denmark
| | - Finn Gustafsson
- Department of Cardiology, Rigshospitalet University Hospital, Copenhagen 2100, Denmark
| | - Lars Gullestad
- Department of Cardiology, Oslo University Hospital, Oslo 0424, Norway
- Faculty of Medicine, University of Oslo, Oslo 0316, Norway
- KG Jebsen Center for Cardiac Research, and Center for Heart Failure Research, University of Oslo, Oslo 0316, Norway
| | - Kari Nytrøen
- Department of Cardiology, Oslo University Hospital, Oslo 0424, Norway
- Faculty of Medicine, University of Oslo, Oslo 0316, Norway
- KG Jebsen Center for Cardiac Research, and Center for Heart Failure Research, University of Oslo, Oslo 0316, Norway
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Abstract
Volume infusions are one of the commonest clinical interventions in critically ill patients yet the relationship of volume to cardiac output is not well understood. Blood volume has a stressed and unstressed component but only the stressed component determines flow. It is usually about 30 % of total volume. Stressed volume is relatively constant under steady state conditions. It creates an elastic recoil pressure that is an important factor in the generation of blood flow. The heart creates circulatory flow by lowering the right atrial pressure and allowing the recoil pressure in veins and venules to drain blood back to the heart. The heart then puts the volume back into the systemic circulation so that stroke return equals stroke volume. The heart cannot pump out more volume than comes back. Changes in cardiac output without changes in stressed volume occur because of changes in arterial and venous resistances which redistribute blood volume and change pressure gradients throughout the vasculature. Stressed volume also can be increased by decreasing vascular capacitance, which means recruiting unstressed volume into stressed volume. This is the equivalent of an auto-transfusion. It is worth noting that during exercise in normal young males, cardiac output can increase five-fold with only small changes in stressed blood volume. The mechanical characteristics of the cardiac chambers and the circulation thus ultimately determine the relationship between volume and cardiac output and are the subject of this review.
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Affiliation(s)
- S Magder
- Department of Critical Care, McGill University Health Centre, 1001 Decarie Blvd., Montreal, Quebec, H4A 3J1, Canada.
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10
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Abstract
PURPOSE OF REVIEW Critical care physicians frequently try to manipulate the preload of the heart to optimize cardiac function. There is, however, still debate as to what actually indicates the preload of the heart. RECENT FINDINGS Although central venous pressure (CVP) is commonly used to estimate cardiac filling, it is often argued that it is a poor indicator of preload. This is likely true if one does not understand what preload is, principles of measurement with fluid filled systems, the effect of respiratory efforts on the measurement, the physiological determinants of CVP, and finally which point on the tracing to use as the estimate of the preload of the heart. When these are considered, however, the value of the CVP at the base of the 'c' wave gives a good indication of cardiac preload and a value which can be followed. SUMMARY When properly measured CVP can be a useful guide to the filling status of the right ventricle. CVP is especially useful when followed over time and combined with a measurement of cardiac output. Importantly, preload is only one of the factors determining cardiac output and it must be integrated into a comprehensive approach that takes into account changes in cardiac function and the return of blood to the heart. Finally, the specific value of preload does not indicate volume responsiveness.
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Dall CH, Gustafsson F, Christensen SB, Dela F, Langberg H, Prescott E. Effect of moderate- versus high-intensity exercise on vascular function, biomarkers and quality of life in heart transplant recipients: A randomized, crossover trial. J Heart Lung Transplant 2015; 34:1033-41. [PMID: 25840503 DOI: 10.1016/j.healun.2015.02.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 01/02/2015] [Accepted: 02/01/2015] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Growing evidence in long-term treatment of heart transplant (HTx) recipients indicates effects of high-intensity interval training (HIIT) on several parameters, including oxygen uptake, vascular function and psychological distress. In this study we compare the effect of HIIT vs continued moderate training (CON) on vascular function, biomarkers and health-related quality of life (HRQoL) in HTx recipients. METHODS A randomized, controlled crossover trial of stable HTx recipients >12 months after transplantation was done on patients with 12 weeks of HIIT or 12 weeks of CON, followed by a 5-month washout and crossover. Outcomes included endothelial function, arterial stiffness, biomarkers, HRQoL and markers of anxiety and depression. RESULTS Sixteen HTx recipients (mean age 52 years, 75% male) completed the study. HIIT increased VO(2peak) more than CON (between-group difference, p < 0.001). The physical component score of the 36-item Short Form (SF-36) was increased significantly in HIIT patients (p = 0.02) and borderline increased in CON patients (p = 0.07), whereas there was no significant effect of exercise on the mental component. Depression score decreased significantly in HIIT patients (p = 0.04) with no change in CON patients (p = 0.75), whereas anxiety score decreased significantly in both HIIT (p < 0.01) and CON (p < 0.05) patients. There were no between-group differences in any of the measures (all p > 0.05). Arterial stiffness and biomarkers were not changed, nor did endothelial function change after HIIT (p = 0.08) or CON (p = 0.68). CONCLUSIONS HIIT and CON are both well tolerated and induce similar improvements in physical components of HRQoL and in markers of anxiety. Effects of either training modality on vascular function and biomarkers could not be confirmed.
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Affiliation(s)
- Christian H Dall
- Department of Cardiology, Bispebjerg Hospital, University of Copenhagen; Institute of Sports Medicine Copenhagen (ISMC/MRRU).
| | - Finn Gustafsson
- Department of Cardiology, Heart Centre, Rigshospitalet, University of Copenhagen
| | | | - Flemming Dela
- Xlab, Center for Healthy Aging, University of Copenhagen
| | - Henning Langberg
- CopenRehab, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Eva Prescott
- Department of Cardiology, Bispebjerg Hospital, University of Copenhagen
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Dall CH, Snoer M, Christensen S, Monk-Hansen T, Frederiksen M, Gustafsson F, Langberg H, Prescott E. Effect of high-intensity training versus moderate training on peak oxygen uptake and chronotropic response in heart transplant recipients: a randomized crossover trial. Am J Transplant 2014; 14:2391-9. [PMID: 25135383 DOI: 10.1111/ajt.12873] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 06/16/2014] [Accepted: 06/16/2014] [Indexed: 01/25/2023]
Abstract
In heart transplant (HTx) recipients, there has been reluctance to recommend high-intensity interval training (HIIT) due to denervation and chronotropic impairment of the heart. We compared the effects of 12 weeks' HIIT versus continued moderate exercise (CON) on exercise capacity and chronotropic response in stable HTx recipients >12 months after transplantation in a randomized crossover trial. The study was completed by 16 HTx recipients (mean age 52 years, 75% males). Baseline peak oxygen uptake (VO2peak ) was 22.9 mL/kg/min. HIIT increased VO2peak by 4.9 ± 2.7 mL/min/kg (17%) and CON by 2.6 ± 2.2 mL/kg/min (10%) (significantly higher in HIIT; p < 0.001). During HIIT, systolic blood pressure decreased significantly (p = 0.037) with no significant change in CON (p = 0.241; between group difference p = 0.027). Peak heart rate (HRpeak ) increased significantly by 4.3 beats per minute (p = 0.014) after HIIT with no significant change in CON (p = 0.34; between group difference p = 0.027). Heart rate recovery (HRrecovery ) improved in both groups with a trend toward greater improvement after HIIT. The 5-month washout showed a significant loss of improvement. HIIT was well tolerated, had a superior effect on oxygen uptake, and led to an unexpected increase in HRpeak accompanied by a faster HRrecovery . This indicates that the benefits of HIIT are partly a result of improved chronotropic response.
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Affiliation(s)
- C H Dall
- Department of Cardiology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark; Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
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Nytrøen K, Gullestad L. Exercise after heart transplantation: An overview. World J Transplant 2013; 3:78-90. [PMID: 24392312 PMCID: PMC3879527 DOI: 10.5500/wjt.v3.i4.78] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 07/15/2013] [Accepted: 07/25/2013] [Indexed: 02/05/2023] Open
Abstract
While life expectancy is greatly improved after a heart transplant, survival is still limited, and compared to the general population, the exercise capacity and health-related quality of life of heart transplant recipients are reduced. Increased exercise capacity is associated with a better prognosis. However, although several studies have documented positive effects of exercise after heart transplantation (HTx), little is known about the type, frequency and intensity of exercise that provides the greatest health benefits. Moreover, the long-term effects of exercise on co-morbidities and survival are also unclear. Exercise restrictions apply to patients with a denervated heart, and for decades, it was believed that the transplanted heart remained denervated. This has since been largely disproved, but despite the new knowledge, the exercise restrictions have largely remained, and up-to-date guidelines on exercise prescription after HTx do not exist. High-intensity, interval based aerobic exercise has repeatedly been documented to have superior positive effects and health benefits compared to moderate exercise. This applies to both healthy subjects as well as in several patient groups, such as patients with metabolic syndrome, coronary artery disease or heart failure. However, whether the effects of this type of exercise are also applicable to heart transplant populations has not yet been fully established. The purpose of this article is to give an overview of the current knowledge about the exercise capacity and effect of exercise among heart transplant recipients and to discuss future exercise strategies.
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Nytrøen K, Gullestad L. [Exercise after heart transplantation--old principles needs reevaluation]. TIDSSKRIFT FOR DEN NORSKE LEGEFORENING 2013; 133:2030-1. [PMID: 24129530 DOI: 10.4045/tidsskr.13.0903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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15
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Rustad LA, Nytrøen K, Amundsen BH, Gullestad L, Aakhus S. One year of high-intensity interval training improves exercise capacity, but not left ventricular function in stable heart transplant recipients: a randomised controlled trial. Eur J Prev Cardiol 2012. [PMID: 23185084 DOI: 10.1177/2047487312469477] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Heart transplant recipients have lower exercise capacity and impaired cardiac function compared with the normal population. High-intensity interval training (HIIT) improves exercise capacity and cardiac function in patients with heart failure and hypertension, but the effect on cardiac function in stable heart transplant recipients is not known. Thus, we investigated whether HIIT improved cardiac function and exercise capacity in stable heart transplant recipients by use of comprehensive rest- and exercise-echocardiography and cardiopulmonary exercise testing. DESIGN AND METHODS Fifty-two clinically stable heart transplant recipients were randomised either to HIIT (4 × 4 minutes at 85-95% of peak heart rate three times per week for eight weeks) or to control. Three such eight-week periods were distributed throughout one year. Echocardiography (rest and submaximal exercise) and cardiopulmonary exercise testing were performed at baseline and follow-up. RESULTS One year of HIIT increased VO 2peak from 27.7 ± 5.5 at baseline to 30.9 ± 5.0 ml/kg/min at follow-up, while the control group remained unchanged (28.5 ± 7.0 vs. 28.0 ± 6.7 ml/kg per min, p < 0.001 for difference between the groups). Systolic and diastolic left ventricular functions at rest and during exercise were generally unchanged by HIIT. CONCLUSIONS Whereas HIIT is feasible in heart transplant recipients and effectively improves exercise capacity, it does not alter cardiac systolic and diastolic function significantly. Thus, the observed augmentation in exercise capacity is best explained by extra-cardiac adaptive mechanisms.
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Affiliation(s)
- Lene A Rustad
- Department of Cardiology, Oslo University Hospital HF, Rikshospitalet, Norway
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16
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Nytrøen K, Rustad LA, Aukrust P, Ueland T, Hallén J, Holm I, Rolid K, Lekva T, Fiane AE, Amlie JP, Aakhus S, Gullestad L. High-intensity interval training improves peak oxygen uptake and muscular exercise capacity in heart transplant recipients. Am J Transplant 2012; 12:3134-42. [PMID: 22900793 DOI: 10.1111/j.1600-6143.2012.04221.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Heart transplant (HTx) recipients usually have reduced exercise capacity with reported VO(2peak) levels of 50-70% predicted value. Our hypothesis was that high-intensity interval training (HIIT) is an applicable and safe form of exercise in HTx recipients and that it would markedly improve VO(2peak.) Secondarily, we wanted to evaluate central and peripheral mechanisms behind a potential VO(2peak) increase. Forty-eight clinically stable HTx recipients >18 years old and 1-8 years after HTx underwent maximal exercise testing on a treadmill and were randomized to either exercise group (a 1-year HIIT-program) or control group (usual care). The mean ± SD age was 51 ± 16 years, 71% were male and time from HTx was 4.1 ± 2.2 years. The mean VO(2peak) difference between groups at follow-up was 3.6 [2.0, 5.2] mL/kg/min (p < 0.001). The exercise group had 89.0 ± 17.5% of predicted VO(2peak) versus 82.5 ± 20.0 in the control group (p < 0.001). There were no changes in cardiac function measured by echocardiography. We have demonstrated that a long-term, partly supervised and community-based HIIT-program is an applicable, effective and safe way to improve VO(2peak) , muscular exercise capacity and general health in HTx recipients. The results indicate that HIIT should be more frequently used among stable HTx recipients in the future.
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Affiliation(s)
- K Nytrøen
- Department of Cardiology, Oslo University Hospital HF Rikshospitalet, Norway.
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Nytrøen K, Rustad LA, Gude E, Hallén J, Fiane AE, Rolid K, Holm I, Aakhus S, Gullestad L. Muscular exercise capacity and body fat predict VO(2peak) in heart transplant recipients. Eur J Prev Cardiol 2012; 21:21-9. [PMID: 22659939 DOI: 10.1177/2047487312450540] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Heart transplant (HTx) recipients usually have reduced exercise capacity, with reported VO2peak levels of 50-70% of predicted values. This study aimed to evaluate central and peripheral factors predictive of VO2peak. METHODS AND RESULTS Fifty-one clinically stable HTx recipients >18 years old and 1-8 years after HTx, underwent maximal exercise testing on a treadmill. Clinical laboratory, haemodynamic and echocardiographic data, lung function, and isokinetic muscle strength and muscular exercise capacity were recorded. The mean ± SD age was 52 ± 16 years, 71% were male, and time from HTx was 4.1 ± 2.2 years. The patients were assigned to one of two groups: VO2peak ≤or >27.3 ml/kg/min, which was the median value, corresponding to 80% of predicted value. The group with the higher VO2peak had significantly lower body mass index, body fat, and triglycerides, and significantly higher body water, muscular exercise capacity, high-density lipoprotein (HDL) cholesterol, lung function, mitral annular velocity, peak ventilation, O2 pulse, and VE/VCO2 slope. Donor age, recipient age, sex, medication, ischaemic time, cardiac dimensions, systolic function, and chronotropic responses during exercise were similar. Multiple regression analysis showed that muscular exercise capacity and body fat were the strongest VO2peak predictors. CONCLUSIONS Chronotropic incompetence is not a limiting factor for exercise capacity in a population of relatively fit HTx patients. The most significant predictors, representing only peripheral factors, are similar to those often determining VO2peak in healthy, non-athletic individuals. Our findings emphasize the importance of a low percentage of body fat and high muscular exercise capacity in order to attain a sufficient VO2peak level after HTx.
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Affiliation(s)
- Kari Nytrøen
- Oslo University Hospital HF Rikshospitalet, Oslo, Norway
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18
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Hsieh PL, Wu YT, Chao WJ. Effects of exercise training in heart transplant recipients: a meta-analysis. Cardiology 2011; 120:27-35. [PMID: 22094922 DOI: 10.1159/000332998] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 08/25/2011] [Indexed: 12/13/2022]
Abstract
OBJECTIVES Muscle wasting and exercise intolerance are common in heart transplant recipients. Most studies on the effects of exercise training have used relatively small sample sizes and are heterogeneous in nature. The purpose of this meta-analysis was to systematically review the relevant studies and investigate the effects of exercise training on exercise capacity and muscle strength in heart transplant recipients. METHODS A systematic search was adopted from electronic databases and relevant references, using medical subject heading key words related to heart transplantation and exercise. Only randomized controlled trials with exercise intervention versus usual care were included. The data were expressed as the weighted mean differences with 95% confidence intervals (CIs). RESULTS Altogether 6 studies were included. Peak oxygen consumption (VO(2)) was reported in 4 trials (117 patients), and muscle strength was reported in 3 trials (67 patients). Peak VO(2) was significantly increased by 2.34 ml/kg/min (95% CI 0.63-4.05). One-repetition maxima of the chest press (23.28 kg, 95% CI 0.64-45.91) and leg press (28.84 kg, 95% CI 5.70-51.98) were significantly improved by exercise training. CONCLUSION Exercise training is recommended for heart transplant recipients to improve peak VO(2) and muscle strength despite the small number of trials included in this meta-analysis.
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Affiliation(s)
- Ping-Lun Hsieh
- School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
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20
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Van Laethem C, Bartunek J, Goethals M, Verstreken S, Walravens M, De Proft M, Keppens C, Calders P, Vanderheyden M. Chronic Kidney Disease is Associated With Decreased Exercise Capacity and Impaired Ventilatory Efficiency in Heart Transplantation Patients. J Heart Lung Transplant 2009; 28:446-52. [DOI: 10.1016/j.healun.2009.01.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 01/07/2009] [Accepted: 01/21/2009] [Indexed: 01/09/2023] Open
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Wu YT, Chien CL, Chou NK, Wang SS, Lai JS, Wu YW. Efficacy of a home-based exercise program for orthotopic heart transplant recipients. Cardiology 2008; 111:87-93. [PMID: 18376119 DOI: 10.1159/000119695] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Accepted: 10/09/2007] [Indexed: 12/22/2022]
Abstract
BACKGROUND A hospital-based cardiac rehabilitation program can significantly improve the cardiopulmonary endurance and quality of life (QOL) in patients after orthotopic heart transplantation (OHT). Home-based programs for these patients have advantages of low cost and high accessibility, but little is known about their efficacy. This prospective study was designed to evaluate the effect of an 8-week home-based exercise program on muscular strength and endurance of lower limbs, aerobic capacity and QOL in OHT recipients. METHODS Thirty-seven OHT recipients were randomized into exercise (n = 14) or control (n = 23) groups. Exercise group subjects were to exercise at least 3 times a week for 8 weeks. Each subject was evaluated by Cybex testing of right quadriceps strength and endurance, 1-min sit-to-stand test, a symptom-limited maximal exercise test and QOL assessment before and after 8 weeks. RESULTS Subjects in the exercise group improved significantly in sit-to-stand test, fatigue index of the right quadriceps, maximal workload achieved and physical domain of QOL compared to controls after 8 weeks, regardless of older age and lower value for sit-to-stand test at baseline. CONCLUSIONS OHT recipients can significantly improve their muscular endurance, sit-to-stand test scores and QOL after a medically directed home-based exercise program.
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Affiliation(s)
- Ying-Tai Wu
- School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan.
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22
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Abstract
Central venous pressure (CVP) is commonly measured, but its clinical use is still not clear. We argue that the interpretation of the CVP needs to be considered in conjunction with an assessment of cardiac output. The objective of this study was to define an elevated CVP as one in which there is a low probability for cardiac output to increase with a volume infusion through a Starling mechanism by relating the initial CVP (measured relative to a reference point 5 cm below the sternal angle) to the response in cardiac output with volume infusion. The authors studied consecutive patients who had pulmonary artery catheters in place and who had a volume challenge as part of routine management as ordered by the treating physician. To ensure an adequate test of the Starling mechanism, data were included only if the volume infusion increased CVP by > or = 2 mm Hg. Responders were defined a priori as those with an increase in cardiac index > or = 300 and nonresponders as < 300 mL/min/m2. Patients failed to respond to volume infusion at all CVP values, and even 25% of those with CVP < 5 mm Hg were nonresponders. However, when CVP was > 10 mm Hg, physicians prescribed less fluid challenges, and when they did, a positive response was much less likely. Change in blood pressure or changes in urine output with volume infusion correlated poorly with change in cardiac index. A CVP of > 10 mm Hg should be considered high, and the probability of an increase in cardiac output with volume infusion is low. This value is a reasonable upper limit for algorithms for empiric fluid challenges.
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Affiliation(s)
- Sheldon Magder
- McGill University Health Centre, Royal Victoria Hospital, Montreal, Quebec, Canada.
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Abstract
OBJECTIVE To review the clinical use of central venous pressure measurements. DATA SOURCES The Medline database, biographies of selected articles, and the author's personal database. DATA SYNTHESIS Four basic principles must be considered. Pressure measurements with fluid-filled systems are made relative to an arbitrary reference point. The pressure that is important for preload of the heart is the transmural pressure, whereas the pressure relative to atmosphere still affects other vascular beds outside the thorax. The central venous pressure is dependent upon the interaction of cardiac function and return function. There is a plateau to the cardiac function curve, and once it is reached, further volume loading will not increase cardiac output. CONCLUSIONS If careful attention is paid to proper measurement techniques, central venous pressure can be very useful clinically. However, the physiologic or pathophysiological significance of the central venous pressure should be considered only with a corresponding measurement of cardiac output or at least a surrogate measure of cardiac output.
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Affiliation(s)
- Sheldon Magder
- McGill University Health Centre, Montreal, Quebec, Canada
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25
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Abstract
PURPOSE OF REVIEW The proper use of central venous pressure requires a good understanding of basic measurement techniques and features of the waveform. RECENT FINDINGS If attention is not paid to proper leveling of the transducer and consideration of transmural pressure then major errors are made in the use of central venous pressure. Besides the information gained from the relationship of changes in central venous pressure to changes in cardiac output, there is also much information to be obtained by examining the waveforms of the central venous pressure tracing. Examples are given of rhythm disorders, tricuspid regurgitation, cardiac tamponade, cardiac restriction, and decreased thoracic compliance. SUMMARY There is much more to the measurement of central venous pressure than the simple digital value on the monitor and the actual waveform should always be examined.
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Affiliation(s)
- Sheldon Magder
- McGill University Health Centre, Royal Victoria Hospital, Division of Critical Care, Montreal, Quebec, Canada.
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Abstract
PURPOSE OF REVIEW Central venous pressure is a very common clinical measurement, but it is frequently misunderstood and misused. As with all hemodynamic measurements, it is important to understand its basic principles. RECENT FINDINGS This analysis indicates that it is best to always consider the significance of central venous pressure in the context of the corresponding cardiac output. Even more important is the use of dynamic measures to interpret the meaning of the central venous pressure. This includes the hemodynamic response to fluid load, respiratory variations in central venous pressure, and even the change in central venous pressure with changes in the patient's overall status. SUMMARY The clinical application of central venous pressure measurement requires a good understanding of the concept of the interaction of the function of the heart with the function of the return of blood to the heart.
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Affiliation(s)
- Sheldon Magder
- McGill University Health Centre, Royal Victoria Hospital, Montreal, Quebec, Canada.
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27
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Kon AA. Discussing Nonsurgical Care With Parents of Newborns With Hypoplastic Left Heart Syndrome. ACTA ACUST UNITED AC 2005. [DOI: 10.1053/j.nainr.2005.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Pokan R, Von Duvillard SP, Ludwig J, Rohrer A, Hofmann P, Wonisch M, Smekal G, Schmid P, Pacher R, Bachl N. Effect of high-volume and -intensity endurance training in heart transplant recipients. Med Sci Sports Exerc 2005; 36:2011-6. [PMID: 15570133 DOI: 10.1249/01.mss.0000147630.71210.06] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND A recommended component of heart transplant recipients (HTR) is endurance-oriented exercise therapy. However, the trainability of HTR after transplantation is vague. We examined the effect of high-volume and -intensity exercise training on exercise performance in HTR, compared with HTR undergoing regular rehabilitation training, and sedentary healthy subjects (SHS). METHODS We studied four groups of individuals; of those, three groups were HTR. Subjects were a regularly trained HTR group of denervated (HTR-D; N = 15), reinnervated (HTR-R; N = 26) hearts, a high-volume and -intensity endurance-training group (training time 7-20 h.wk(-1); HTR-ET; N = 12), and a group of sedentary healthy subjects (SHS; N = 21). All participants performed cardiopulmonary exercise testing. RESULTS The HTR-ET achieved a significantly higher performance (255 +/- 47 W, VO(2max) of 45.2 +/- 6.9 mL.kg(-1).min(-1)) in contrast to all other groups (HTR-D: 119 +/- 17 W, VO(2max) of 17.4 +/- 4.5 mL.kg(-1).min(-1); HTR-R: 119 +/- 17 W, VO(2max) of 16.9 +/- 3.7 mL.kg(-1).min(-1); SHS: 184 +/- 19 W, VO(2max) of 35.0 +/- 6.9 mL.kg(-1).min(-1)). The HR at maximal power output in the HTR-ET was 169 +/- 17 bpm and similar to SHS (164 +/- 17 bpm), but significantly higher than HTR-D (125 +/- 16) and HTR-R (142 +/- 10). Maximal lactate concentration (LAmax) of HTR-ET was 9.9 +/- 2.2 mmol.L(-1), comparable to SHS (9.2 +/- 2.1 mmol.L(-1)), and significantly higher than HTR-D (5.5 +/- 1.5 mmol.L(-1)) and HTR-R (5.1 +/- 1.0 mmol.L(-1)). CONCLUSIONS Data suggest that HTR can perform high-volume and -intensity exercise training, reaching exercise performance comparable to or even exceeding values of sedentary or moderately trained healthy subjects.
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Affiliation(s)
- Rochus Pokan
- Department of Sports Physiology, University of Vienna, Vienna, Austria
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30
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Abstract
Exercise intolerance in heart transplant recipients (HTR) has a multifactorial origin, involving complex interactions among cardiac, neurohormonal, vascular, skeletal muscle and pulmonary abnormalities. However, the role of these abnormalities may differ as a function of time after transplantation and of many other variables. The present review is aimed at evaluating the role of cardiac, pulmonary and muscular factors in limiting maximal aerobic performance of HTR, and the benefits of chronic exercise. Whereas pulmonary function does not seem to affect gas exchange until a critical value of diffusing lung capacity is attained, cardiac and skeletal muscle function deterioration may represent relevant factors limiting maximal and submaximal aerobic performance. Cardiac function is mainly limited by chronotropic incompetence and diastolic dysfunction, whereas muscle activity seems to be limited by impaired oxygen supply as a consequence of the reduced capillary network. The latter may be due to either immunosuppressive regimen or deconditioning. Endurance and strength training may greatly improve muscle function and maximal aerobic performance of HTR, and may also reduce side effects of immunosuppressive therapy and control risk factors for cardiac allograft vasculopathy. For the above reasons exercise should be considered an important therapeutic tool in the long-term treatment of heart transplant recipients.
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Affiliation(s)
- Claudio Marconi
- Muscle Physiology and Proteome Section, IBFM-Consiglio Nazionale delle Ricerche, LITA, v Flli Cervi 93, Segrate, 20090 Milan, Italy.
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Leung TC, Ballman KV, Allison TG, Wagner JA, Olson LJ, Frantz RP, Edwards BS, Dearani JA, Daly RC, McGregor CGA, Rodeheffer RJ. Clinical predictors of exercise capacity 1 year after cardiac transplantation. J Heart Lung Transplant 2003; 22:16-27. [PMID: 12531409 DOI: 10.1016/s1053-2498(02)00475-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The exercise capacity of cardiac transplant recipients is reduced compared with normal controls. However, clinical variables predictive of post-transplant exercise capacity have not been well defined. The objective of the present study was to identify clinical features predictive of post-transplant exercise capacity. METHODS Ninety-five cardiac transplant recipients underwent cardiopulmonary testing at 1 year after transplant. The exercise parameters were compared with both pre-transplant values and normal subjects. The relationships between exercise parameters and clinical characteristics were analyzed. RESULTS Mean peak oxygen consumption (VO(2)) and exercise test duration at 1-year post-transplant improved significantly from 16.4 to 19.9 ml/kg/min and 5.5 to 7.6 minutes, respectively (p < 0.001), but were significantly lower than for normal controls (peak VO(2) 34.0 ml/kg/min; exercise duration 11.2 minutes; p < 0.001). Age- and gender-adjusted VO(2) was 54% of predicted. Pre-operative body weight correlated strongly with post-transplant weight (r = 0.80, p < 0.001). Significant recipient predictors of 1-year post-transplant peak VO(2) identified by multivariate regression analysis were age, male gender, body mass index, exercise peak heart rate and duration of post-operative intensive care. Donor variables did not contribute significantly to post-transplant peak VO(2). CONCLUSIONS Peak VO(2) improved after cardiac transplantation but remained significantly impaired compared with normal subjects. In estimating the impact of cardiac transplantation on exercise capacity the most important pre-transplant factors to consider are age, gender and height and weight (or, alternatively, body mass index).
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Affiliation(s)
- Tat-Chi Leung
- Division of Cardiovascular Disease, Mayo Clinic and Foundation, Rochester, Minnesota, USA
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Abstract
When right atrial pressure (Pra) is greater than zero (atmospheric pressure), cardiac output is determined by the intersection of two functions, cardiac function and return function, which is used here to mean the determinants of venous return. When Pra < or = 0, flow is only determined by circuit function. The objective of this analysis was to determine the potential changes in return function that need to occur to allow the maximum cardiac output during exercise when Pra < or = 0 or is constant. The analysis expands on the model of Green and Jackman and includes the effects of changes in circuit parameters, including venous resistance, changes in capacitance, and muscle contractions. The analysis is based on the model of the circulation proposed by Permutt and co-workers, which assumes that the systemic circulation has two lumped compliant regions in parallel with independent inflow and outflow resistances. Changes in total flow in this model can come about by changes in the distribution of flow between the regions, recruitment of unstressed vascular volume, and changes in the regional venous resistances. The data for the analysis are from previous animal studies and are normalized to a 70-kg man. The major conclusions are that, to achieve the high cardiac output that occurs at peak exercise, there need to be marked changes in the distribution of blood flow, recruitment of unstressed volume, and the venous resistance draining vascular beds. A consequence of the increase in peripheral flow is a marked increase in pressure in the veins of the working muscle. Muscle contractions are potentially a very important mechanism for transiently decreasing this pressure and preventing excessive filtration of plasma during exercise.
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Affiliation(s)
- S Magder
- Royal Victoria Hospital, Critical Care Division, McGill University, 687 Pine Avenue West, Montréal, QC H3A 1A1, Canada.
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