Sherry-Ann Brown, MD, PhD is a physician scientist with clinical and research emphases in Preventive Cardiology, Cardio-Oncology, and Heart Disease in Women. She is a pioneer in Preventive Cardio-Oncology. Her blogs are available at DrBrownCares.Com, CardioOncTrain.Com, PrevCardioOnc.Com (coming soon), and LyricalMezzanine.Com. On Twitter, follow @DrBrownCares, @PrevCardioOnc, and @LyricalMezz.
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Preventive Cardio-Oncology: A Role For Cardiopulmonary Stress Testing

Sherry-Ann Brown, MD, PhD

Cardiopulmonary exercise stress testing can be useful in a variety of ways, particularly for Preventive Cardiology and Preventive Cardio-oncology. The test helps to assess for levels of fitness, causes of functional limitation, and evidence of ischemia. Test results can be used to counsel individuals, guide exercise prescriptions, and reassure, encourage, and motivate individuals for lifestyle modification and behavior change.

The exercise ECG portion of the test gives information regarding evidence of ischemia, exercise capacity, and adequacy of heart rate response, and response of blood pressure to exercise. The information of this portion of the test can help to determine whether there are any high-risk cardiac features that need to be addressed, such as evidence of ischemia or hypotensive response to exercise. Limited heart rate response is also useful to help determine whether rate-limiting medications or pacemaker settings need to be adjusted. Often, when medications like metoprolol or pacemaker heart rate response are adjusted, this can improve the function and experience of patients who are previously limited by their heart rate during activity. The exercise capacity information given by the exercise ECG, such as excellent, good, average, below average, fair, or poor can give an indication of individuals’ ability to meaningfully, safely, and successfully pursue exercise. Oftentimes, some patients who have had prior cardiovascular events may shy away from moderate or intense exercise for fear of cardiovascular injury as a result of exertion. Pursuing an exercise ECG portion of the cardiopulmonary stress test can help individuals in such cases recognize that they can perform moderate or intense exercise safely without injuring their heart. The exercise capacity reported on the test can help these individuals see that their exercise or aerobic capacity is poor because of their hesitation to pursue moderate or intense exercise. This can be motivating for individuals to recognize that they can benefit from doing more and that they can do more safely. This is particularly the case for individuals who have experienced a cardiovascular event from spontaneous coronary artery dissection, which does not have many modifiable risk factors, and understandably leads to apprehension in young women diagnosed with this condition. However, the exercise ECG portion alone lacks several informative parameters important for patient care in Preventive Cardiology and Cardio-Oncology.

The specific addition to the test provided by the ‘cardiopulmonary’ portion involves oxygen consumption. If oxygen consumption (or VO2) is below average, limited, or poor, there can be several reasons for this. The most common reasons include cardiac impairment, pulmonary impairment, deconditioning, excess weight, and limited heart rate reserve. There are various parameters in the cardiopulmonary stress test results that will indicate whether deconditioning plays a role, whether BMI plays a role, whether cardiac impairment plays a role (in which case this could be due to low flow from systolic dysfunction or due to diastolic dysfunction or even heart rate), or whether pulmonary impairment plays a role (which could be of varied etiology). This addition to the test also helps patients to objectively see data supporting the suspicion that they have become deconditioned after a cardiovascular event or after cancer therapies. They get to see that the cancer therapies or their subsequent levels of activity following their cardiovascular event could currently or potentially affect their function, and may explain any current functional limitation or in fact set them up for functional limitation going forward. The test can also help patients see the effect of any excess weight on their compromised oxygen consumption. Given that cancer therapies for breast cancer, for example, will often include radiation, surgery, and chemotherapy that can injure the heart and/or the lungs, it is helpful to determine the suggested underlying causes of functional limitation as assessed by oxygen consumption in these patients who have had treatment involving the chest. Performing the cardiopulmonary stress test at baseline before treatment helps individuals see their level of fitness, deconditioning, weight effect, cardiac impairment, or pulmonary impairment, even before ever undergoing cancer therapy. Given that fitness levels and injuries to the heart or the lungs can be affected by cancer therapies, then repeating the test after therapies can show patients the change that has occurred as a response to therapies. This can be helpful for patient to have a sense of their original baseline and goals that they can work towards to supersede even that baseline. For individuals who are not going to undergo cancer therapies, obtaining a baseline also helps individuals with a sense of how much they could potentially achieve. Then, once they have achieved a particular goal, the test can be repeated to show the improvement and continue to inspire motivation. This objective collection of evidence and data that can be used for motivation, reassurance, counseling, and exercise prescription is all key for lifestyle modification and behavior change in Preventive Cardiology and Preventive Cardio-Oncology. Thus, for all these reasons and more cardiopulmonary stress testing will evolve to play a large role in Cardio-Oncology prehabilitation, habilitation, and rehabilitation1,2,3, as we help individuals prepare for, experience well, and long outlive their cancer therapies.

 

References

  1. https://earlycareervoice.professional.heart.org/preventive-cardio-oncology-the-rise-of-prehabilitation/. Accessed April 20, 2019.
  2. Squires RW, Shultz AM, Herrmann J. Exercise Training and Cardiovascular Health in Cancer Patients. Curr Oncol Rep. 2018 Mar 10;20(3):27. doi: 10.1007/s11912-018-0681-2.
  3. Gilchrist SC, Barac A, Ades PA, Alfano CM, Franklin BA, Jones LW, La Gerche A, Ligibel JA, Lopez G, Madan K, Oeffinger KC, Salamone J, Scott JM, Squires RW, Thomas RJ, Treat-Jacobson DJ, Wright JS; American Heart Association Exercise, Cardiac Rehabilitation, and Secondary Prevention Committee of the Council on Clinical Cardiology; Council on Cardiovascular and Stroke Nursing; and Council on Peripheral Vascular Disease. Cardio-Oncology Rehabilitation to Manage Cardiovascular Outcomes in Cancer Patients and Survivors: A Scientific Statement from the American Heart Association. Circulation. 2019 Apr 8:CIR0000000000000679. doi: 10.1161/CIR.0000000000000679. [Epub ahead of print].
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Preventive Cardio-Oncology: The Rise of Prehabilitation

Sherry-Ann Brown, MD, PhD
Figure 1 Prehabilitation: optimization of overall health, wellness, and fitness prior to initiation of therapies that might adversely alter fitness, strength, quality of life, or function.

Figure 1 Prehabilitation: optimization of overall health, wellness, and fitness prior to initiation of therapies that might adversely alter fitness, strength, quality of life, or function.

As I near the end of my job search process and prepare to review offers and sign a contract, it is absolutely incredible to me to consider that I am completing training at just the right time for me in cardiology. While sitting in a preventive cardiology team room, I overheard two exercise specialists describing a project that they plan to present in several weeks at a national conference. I overheard them use the word ‘prehabilitation’. While the word is not brand new in their professional world or even in cardiology, at that time the word was novel to me. I felt excitement rise within me as I recognized the word ‘prehabilitation’ as a concept that I have envisioned for quite some time to be key to what I would like to achieve and develop in the emerging field of preventive cardio-oncology. As a senior cardiology fellow, my training has been particularly enriched in cardio-oncology (see CardioOncTrain.Com), preventive cardiology, heart disease in women, and precision medicine. I plan to have a heavy emphasis on prevention in my practice, and with eventual incorporation of maturing tools in precision medicine. If you too are interested in preventive cardiology and cardio-oncology, you may want to consider a combined practice of preventive cardio-oncology.  If you are also interested in heart disease in women, then you may want to consider preventive cardio-oncology particularly in women, e.g., women with breast cancer.  Yes, that is quite focused, but can be an incredible niche.  Yet, let us take a step back from the idea of preventive cardio-oncology in breast cancer or any other cancer and first consider how far we have come in the broader field of cardio-oncology.

In the burgeoning field of cardio-oncology, one could argue that we are doing quite well as a community with epidemiology and management of cardiovascular toxicities from cancer therapies. Our ability to completely predict cardiovascular toxicity in individuals is still in progress. Nevertheless, the field has come so far regarding what we now understand about pathophysiology, risk factors, and incidence of cardiovascular toxicity. In particular, due to the continuous and rapid innovation in cancer therapies, cardio-oncology continues to grow exponentially. If you are interested in or planning to join the field, now is a great time!

While the main focus in cardio-oncology has been on secondary and tertiary prevention of cardiovascular toxicity and its sequelae, an era is approaching that may focus even more so on primordial and primary prevention of cardiovascular toxicity. What if we could figure out ways to prevent cardiovascular toxicity before it even happens? What if we can even avoid development of risk factors themselves? These two questions point towards a focus on primary and primordial prevention, respectively. Indeed, for decades we have been focusing largely on secondary and tertiary prevention in Cardio-Oncology. Perhaps it is now time to focus more on what would appropriately be termed preventive cardio-oncology, a merger between preventive cardiology and cardio-oncology.

A hallmark of preventive cardiology has long been cardiac – and in fact cardiopulmonary – rehabilitation. This usually would occur in the setting of secondary or tertiary prevention. As such, ‘rehab’ generally has at least a few purposes. One purpose is to help individuals get back to the level of cardiopulmonary function they had prior to their cardiovascular event. A second purpose is to actually optimize their cardiopulmonary function, regardless of their original preexisting starting point, and help them develop a sustainable lifestyle modification program that can hopefully help prevent another event. A third purpose is to provide support and camaraderie that can help individuals regain the confidence they need to develop and maintain heart healthy lifestyle habits, by knowing they’re not alone in the process. For young patients, such as young adult women with spontaneous coronary artery dissection, this third purpose can be particularly beneficial.

Studies are now showing that cardiopulmonary rehab can also be useful in patients who have completed cancer therapy – in a sense as their ‘event’1,2. This is in part because cancer therapies can impact the heart, vasculature, and lungs, as well as other organ systems. In addition, while undergoing therapy for cancer, individuals often tend to lose fitness, energy, strength, and motivation for lifestyle modification, which is entirely understandable. Studies are therefore also showing that individuals who pursue exercise in the form of ‘habilitation’ while undergoing cancer therapies will also often have improved fitness and cardiovascular function and outcomes following the completion of therapy1,3.

Notably, newer studies are suggesting that exercise prior to the initiation of cancer therapies can further improve fitness, strength, quality of life, and cardiovascular function during or upon completion of cancer therapy1,4. This concept of ‘prehabilitation’ is catching on and will most certainly become a centerpiece and hallmark of primary prevention and perhaps even primordial prevention of cardiovascular toxicities.

Essentially, we need to recognize the impact and power of hysteresis, which suggests that the cardiopulmonary fitness starting point for a patient diagnosed with cancer will determine their cardiopulmonary fitness endpoint after treatment for cancer. This of course is intuitive, but not usually the focus early on in cancer survivorship. Since one in three individuals develop cancer in their lifetime5, it would be reasonable to recommend that all individuals optimize their cardiopulmonary fitness and prioritize lifestyle modification to ensure a desirable cardiopulmonary starting point if ever one is unfortunately diagnosed with cancer. If we take a step back, we realize that is quite similar to the argument for optimizing cardiovascular health in the general population. One in three individuals dies from cardiovascular disease each year6. It is therefore reasonable to recommend that all individuals optimize their cardiovascular health and prioritize lifestyle modification to hopefully help avoid cardiovascular events. When we view (i) cardiopulmonary fitness after cancer therapies and (ii) cardiopulmonary fitness associated with cardiovascular health in the general population through similar lenses, it becomes clear that preventive cardiology and cardio-oncology could potentially come together in an emergent subspecialty of preventive cardio-oncology.

For all individuals, the overarching goal is optimal cardiovascular health based on life’s simple seven: diet, physical activity, obesity, cholesterol, diabetes, blood pressure, and cigarette smoking, in the context of non-modifiable and also nontraditional modifiable risk factors. For individuals with cancer, who become survivors at the moment of diagnosis7, additional goals are preserving  strength, endurance, quality of life, and function.

To achieve long-lasting success in preventive cardio-oncology, we will need to consider three Ps: protocols, partnerships, and payments. In this hot new field of preventive cardio-oncology in which you and I might be trailblazing, together we need to develop standard protocols that can be used across the nation – and in fact across the world – to provide the best care for our patients. We will need Scientific Statements and Guidelines as the backbone of our practice. To facilitate evidence-based prevention, we will need a combination of retrospective, cohort, and case studies, as well as clinical trials. We will need to be sure to practice team-based care and forge lasting partnerships among clinicians, exercise specialists, and others in order to guide patients along gentle, individualized pre-habilitation, habilitation, and rehabilitation care plans. Importantly, relevant payment structures will need to be developed and adequately compensated by government, state, and private insurance.

An exciting path is before us Early Career folks in preventive cardio-oncology, as we shape the opportunity to practice in cardio-oncology from the perspective of primordial, primary, secondary, and tertiary prevention in women and in everyone.

 

References

  1. SquiresRW, Shultz AM, HerrmannJ. Exercise Training and Cardiovascular Health in Cancer Patients. Curr Oncol Rep. 2018 Mar 10;20(3):27. doi: 10.1007/s11912-018-0681-2.
  2. Lee K, Tripathy D, Demark-Wahnefried W, Courneya KS, Sami N, Bernstein L, Spicer D, Buchanan TA, Mortimer JE, Dieli-Conwright CM. Effect of Aerobic and Resistance Exercise Intervention on Cardiovascular Disease Risk in Women With Early-Stage Breast Cancer: A Randomized Clinical Trial. JAMA Oncol. 2019 Mar 28. doi: 10.1001/jamaoncol.2019.0038.
  3. https://journals.lww.com/oncology-times/pages/articleviewer.aspx?year=2019&issue=02050&article=00014&type=Fulltext. Accessed April 4, 2019.
  4. https://www.acc.org/about-acc/press-releases/2017/03/08/14/42/history-of-exercise-helps-prevent-heart-disease-after-breast-cancer. Accessed April 4, 2019.
  5. https://www.cancer.org/cancer/cancer-basics/lifetime-probability-of-developing-or-dying-from-cancer.html. Accessed April 4, 2019.
  6. https://professional.heart.org/idc/groups/ahamah-public/@wcm/@sop/@smd/documents/downloadable/ucm_503396.pdf. Accessed April 4, 2019.
  7. Rock CL, Doyle C, Demark-Wahnefried W, Meyerhardt J, Courneya KS, Schwartz AL, Bandera EV, Hamilton KK, Grant B, McCullough M, Byers T, Gansler T. Nutritionand physical activity guidelines for cancer survivors. CA CancerJ Clin. 2012 Jul-Aug;62(4):243-74. doi: 10.3322/caac.21142.