Exercise as it relates to Disease/Exercising with heart failure; does it result in pulmonary hypertension and exercise intolerance?

This is a critical analysis on the article from the Journal of the American College of Cardiology “Pulmonary Hypertension and Exercise Intolerance in Patients with Heart Failure” – Javed Butler, MD; Don B Chomsky (1999).

What is the background to this research?
is the archetype of physiological demands placed on the body. It greatly benefits patients, though the capacity to is frequently reduced in those with. occurs when the heart cannot keep up with the bodies workload, caused by impaired and  performance. The heart takes temporary measures to try mask the problem including:
 * Stretching (enlargement)
 * Increased heart-rate
 * (compensation for power loss)

is a serious problem in heart failure patients; characterised by, shortness of breath and sometimes coughing. Pulmonary vascular resistance (PVR) may contribute to this by impaired pulmonary blood flow. During exercise, pulmonary pressure increases due to increased blood flow. then increases due to pulmonary pressures, resulting in a drop in PVR.

Regardless of the of,  has modest clinical benefits. Though is dangerous when these complications aren’t taken into consideration.

Where is the research from?
The article was published in the Journal of the American College of Cardiology by Science Inc. Per Impact Factor, it was deemed the top Cardiovascular Journal worldwide (2013–2016). The funding was a Grant-in-Aid from the National. There is no evidence of bias regarding the large voluntary non-for-profit organisation, labelled ‘trustworthy’ in compliance with HONcode. The study was approved by the.

Primary author, Javed Butler, has a strong cardiovascular repute, being board certified in cardiovascular/ transplant medicine, and advanced. He has written 450+ peer-reviewed publications, and is on the editorial board of several cardiovascular journals. Dr. Don B Chomsky, has 27 years of experience in specialty fields of and.

What kind of research was this?
This is an observational ; involving a snapshot of the clinical population at a set point. The data derived can contain multiple variables, though won’t help determine cause/ effect. The population are not compared to a control group, instead compared within each other. It would make it easier to decipher clinical results if derived from normal population findings.

What did the research involve?
The research for this study involved 320 ambulatory patients, who underwent at the Vanderbilt Heart Failure and Transplant Programs, between December 1993 - March 1997. The criteria included:
 * An of <40%
 * No dependancy/ mechanical support
 * No  limitations
 * No arterial oxygen desaturation/ exhibitation

The protocol initially involved a insertion procedure. Supine central hemodynamic measurements were monitored (at rest and throughout exercise); including, haemoglobin , pulmonary arterial pressure, right atrial pressure and. Participants performed a modified Naughton Protocol on a treadmill (3 minute stages) to find peak VO2. Patients continued exercising until symptoms of / forced them to stop. Respiratory gas exchange analysis and blood sampling was also taken.

This methodology was not the best approach. The patient population holds bias, as patients with mild are rarely referred to specialty / transplant programs. Perhaps having a wider patient cohort and/or a control group could allow for a greater  comparison. The time frame this study was conducted in seems unreasonable, due to being a lengthy process. Not to mention the ~$1.365 million (at ~$4265.21 per patient) cost. Pushing participants to exhaustion could be dangerous regardless of meeting exclusion criteria. No indication of incidences, further complications or care taken after the protocol for the patients were mentioned, which calls for question on supervision precautions taken. Also, no measure of client’s current medications/ history were stated.

What were the basic results?

 * 18% had peak VO2 of >16ml/min/kg
 * Pulmonary wedge pressure decreased in 28% (indicating impairment of left ventricular filling)
 * PVR increased in patients with normal resting pulmonary hypertension (Group 1)
 * PVR decreased in patients with severe resting pulmonary hypertension (Group 4)
 * The absence of major exertion symptoms does not exclude possibility of severe pulmonary hypertension

The implications of their findings were not over emphasised, as each statement follows statistical data. Most findings in this report display comparable results from similar studies (and are mentioned). However, some data throughout the study is inconsistent. It was stated in the results that 18% of the patients had peak VO2 levels >16ml/min/kg. In the discussion, it states the 16% of patients had the same result. Further on, it states 58/320 patients (18.1%) had >16ml/min/kg.

What conclusions can we take from this research?
The study concludes that the presence of pulmonary hypertension is not always associated with major, and that it contributes by impairment of response. The conclusion reinstates results, stating that the hypothesis was supported; though they do so in an unclear way. Initially it could be read that 50% of patients had a VO2 >16ml/min/kg, which is incorrect (stated as both 16% and 18% in the results/ discussion). Instead it states that from the 58 patients, half had, which is not clearly articulated throughout the study.

As the research was observed through a large cohort, there is a sufficient degree of evidence to support. Although, the selection criteria is restricted as it only took patients from a specific transplant program. This bias in turn could damper results. Furthermore, there is no section for ‘study limitations/ suggestions for future research’ which could be beneficial for authors to reflect and suggest.

Practical advice
Vast progress in the diagnosis and treatment of has been confirmed over recent years. Due to this high prevalence, large amounts of research have been conducted to find the relationship between and  performance. However, to compare with real-world implications, this study would be more applicable inclusive of, patient medication, and physical activity levels being revealed.

It is vital that exercise be prescribed only after signing and completing an ESSA adult pre-exercise screening. This allows patient/ practitioner protection, through professional/ ethical conduct. Furthermore, strong supervision and precautions are fundamental for any undertaken. This research was led by with significant funding. In taking on this practical advice; understanding of considerations and guidelines are highly recommended.

Further information/ support
If you are interested in further reading about this subject matter; below are resources to provide additional information support:
 * Heart Failure: Guidelines/ Tools: https://www.heartfoundation.org.au/for-professionals/clinical-information/heart-failure
 * Effects of Hypertension: https://www.healthline.com/health/high-blood-pressure-hypertension/effect-on-body#1
 * Catheter: Procedures/ Treatment: https://www.svhhearthealth.com.au/procedures/procedures-treatments/right-heart-catheter
 * Catheterisation Animation: https://www.webmd.com/heart-disease/video/cardiac-catheterization