Special Considerations for Cardiovascular Disease: Chronic Stable Angina and Coronary Artery Bypass Graft Surgery


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Special Considerations for Cardiovascular Disease: Chronic Stable Angina and Coronary Artery Bypass Graft Surgery


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INTRODUCTION


For patients with cardiovascular disease, exercise is a critically important intervention and should be prioritized to slow the progression of disease and prevent or reverse physical deconditioning. Along with other therapeutics prescribed to patients with cardiovascular disease, exercise training should be viewed as medicinal. As is the case with all medicines, it is critically important that the optimal “dose” of exercise is recommended to patients. This chapter presents background and special considerations related to exercise testing, prescription, and progression for individuals with chronic stable angina and for postsurgical patients following coronary revascularization. Although there are issues and concerns that specifically pertain to individuals who have been revascularized versus those with chronic angina, many of the benefits and limitations of exercise training apply to both types of patients.







Case Study 10-1



Ms. Case Study-Angina


Ms. Case Study-Angina is a 64-year-old female that recently retired from providing pastoral care at a local college. She has a past history of endometriosis, Ménière disease, gastroesophageal reflux disease (GERD), asthma, hyperlipidemia, osteoporosis, and metabolic syndrome. For many months, she has been experiencing exertional subscapular pain. Additionally, she frequently experiences chest pain which, at a minimum, is partially related to GERD. Unlike the subscapular pain, the chest pain is more random, occurring both while at rest and with exertion. She underwent nuclear imaging testing that was positive for electrocardiogram (ECG) changes that occurred with chest and subscapular pain. Ms. Case Study-Angina had a heart catheterization which revealed a 50% obstruction of the left anterior descending artery and a 90% obstruction of a small right coronary artery, neither of which was amenable to intervention. Thus, she is being treated for her GERD, cardiovascular disease, and angina pectoris medically with the following regimen: aspirin, isosorbide mononitrate, 30 mg; extended-release metoprolol, 25 mg; atorvastatin, 40 mg; and omeprazole, 40 mg.


Ms. Case Study-Angina reports to cardiac rehabilitation (CR) for her baseline exercise tolerance test and consult with a preventive cardiologist 28 days after her catheterization. Her cardiac risk factor history includes a positive family history for premature coronary artery disease, hypertension, hyperlipidemia, and insulin resistance. She reports that she continues to have moderate threshold exertional angina which always resolved with rest. In particular, she reported experiencing subscapular pain when exerting in the cold weather. She claims that her symptoms are slightly but not substantially better since starting with isosorbide mononitrate and β-blocker therapy.


An exercise tolerance test was performed, and she exercised for 6.5 minutes of a standard Bruce protocol. Ms. Case Study-Angina first reported subscapular pain at about 5 minutes into the test and at a heart rate (HR) of 114 bpm. At peak exercise, she reported 2 out of 4 angina pain with ECG changes of 1- to 2-mm ST depression. Her peak HR and volume of oxygen consumed per unit time (O2) were 124 bpm and 17.5 mL O2 ∙ kg−1 ∙ min−1, respectively. Her respiratory exchange ratio was 1.02, which would suggest that the test was physiologically not maximal. Her peak O2 measures would place her at about 20% above age- and gender-matched females entering CR with a similar diagnosis (1). On the other hand, her fitness measures would place her at about the 25th percentile of otherwise healthy women of a similar age (11). Currently, her body mass index (BMI) is 27, which would categorize her as overweight. Other baseline values include the following:


  Waist circumference = 94 cm (37 in)


  Resting ECG: HR is normal sinus rhythm = 68 bpm


  Resting blood pressure (BP): 144/80 mm Hg


  Blood test


  Total cholesterol = 124 mg ∙ dL−1


  Triglyceride = 59 mg ∙ dL−1


  High-density lipoprotein (HDL) cholesterol = 54 mg ∙ dL−1


  Low-density lipoprotein (LDL) cholesterol = 58 mg ∙ dL−1


  Glycolated hemoglobin (HbA1C) = 5.9


Based on the results of the stress test, a short-term goal for CR was established that the exercise program would include treadmill walking, rowing and cycle ergometry, and strength training (Table 10.1). Additionally, given that her recent HbA1C level was elevated at 5.9, the importance of weight loss was emphasized. A mutually agreed on goal of 2.5–5 kg (5.5–11 lb) weight loss was established.








Table 10.1


Cardiac Rehabilitation Exercise Training Summary for Ms. Case Study-Angina









































































































































































Treadmill



Session


HR (bpm)


BP (mm Hg)


Time


Speed/G


HR/RPE


Rower Time/HR


Cycle Time/HR


Angina Scale


   1


73


130/80


:15


2.0/1.0


98/12


:05/94


:05/92


1/4


   3


72


120/84


:19


2.0/0.5


90/11


:06/88


:06/87


0/4


  6


66


140/90


:22


2.0/1.0


97/12


:07/93


:09/93


1/4


  9


73


130/80


:26


2.0/1.0


102/12  


:08/90


:08/92


0/4


12


72


120/84


:30


2.1/0.5


98/12


:08/88


:08/87


2/4


15


66


140/90


:30


2.0/1.0


97/11


:08/93


:08/93


1/4


18


78


144/94


:30


2.3/2.5


98/12


:08/94


:08/99


1/4


19


77


132/84


:30


2.1/1.0


96/13


:08/93


:08/96


2/4


20


76


130/78


:30


2.1/1.0


94/13


:08/97


:08/91


2/4


21


73


130/80


:30


2.3/2.0


96/12


:08/94


:08/92


1/4


24


72


120/84


:30


2.3/2.0


94/13


:10/88


:10/87


1/4


27


66


124/80


:30


2.3/2.5


95/13


:10/93


:10/95


1/4


30


84


128/72


:30


2.3/2.5


97/13


:10/96


:10/94


1/4


33


66


150/84


:30


2.4/2.5


93/13


:10/98


:10/88


1/4


36


76


160/80


:30


2.5/2.5


95/13


:10/93


:10/95


1/4


G, grade.


A target HR of 104 bpm for aerobic training was established based on the guidelines that recommend that patients with angina exercise at an HR of at least 10 bpm below their angina threshold (3). At the first session of CR, Ms. Case Study-Angina walked on the treadmill for 15 minutes at a speed of 2.0 mph, 1% grade.


The speed and grade was selected based on the patient reporting that it was “moderate” (rating of perceived exertion [RPE] = 12) intensity. At the end of the 15 minutes, her HR was 98, and she reported 2 out of 4 subscapular pain and 2 out of 4 chest angina pain, both of which subsided with the cessation of walking. She also exercised for 5 minutes each on the rower and cycle ergometer, experiencing no discomfort. By session 6, she had increased the duration on the treadmill, cycle, and rower to 22, 7, and 9 minutes, respectively. She continued to experience angina each time she walked on the treadmill.


At session 6, the following resistance training exercises were introduced: arm curl, overhead press, triceps extension, bench press, lateral pull-down, leg extension and press, and hamstring curl. The weight for each of the exercises was selected using a conservative approach and done so while directly observing the patient performing the exercise. Proper technique was emphasized, and the initial weight for the various exercises was determined by selecting a resistance that patient perceived to be “light.” The patient was instructed to exhale during the concentric phase of the exercise and to inhale during the eccentric phase. The goal is to gradually titrate the weight upward so that, eventually, the 10th repetition of a particular set is considered to be “heavy” or “hard” (10).


At session 7, an extended warm-up on the treadmill was attempted. Ms. Case Study-Angina started at 1.5 mph for 5 minutes, and then the speed was increased to 2 mph and the grade was elevated to 1% gradually over the next 5 minutes. She denied any angina despite walking on the treadmill for a total of 25 minutes. By session 12, she had increased the total duration of exercise to 46 minutes, with 30 minutes spent on the treadmill and 8 minutes on both the cycle and rowing ergometers. At session 12, however, she reported 2 out of 4 angina on the treadmill despite the extended warm-up. Starting with session 13, she began to take nitroglycerin about 15 minutes before commencing with her exercise session. Ms. Case Study-Angina took sublingual nitroglycerin while resting in a chair in an attempt to cause vasodilatation of the coronary arteries before beginning exercise. Prior to getting on the treadmill, her BP was rechecked to make sure that it was not too low. Her BP decreased from an entry value of 120/84 to 108/74 mm Hg. She denied any significant symptoms, but she experienced a low-level headache for a few minutes after taking the nitroglycerin. She was able to complete her exercise session without experiencing any angina.


By session 18, she was able to walk for 30 minutes at a speed and grade of 2.3 mph at a 2.5% grade. However, Ms. Case Study-Angina had complaints of experiencing frequent subscapular pain while doing activities of daily living (ADL), in particular walking in the cold and carrying laundry upstairs. Entry BP readings upon arrival at CR have been normal to slightly elevated. In an attempt to remedy her predictably occurring angina, her cardiologist increased her dose of isosorbide mononitrate from 30 to 60 mg.


The first 2 sessions (sessions 19 and 20) after the increase in isosorbide mononitrate, the practice of taking the sublingual nitroglycerin prior to the exercise session was discontinued. In both of these sessions, angina came on at a much lower speed and grade. At session 21, the practice of administering the nitroglycerin 15 minutes prior to beginning the exercise session was reestablished. By session 27, she was able to exercise for a total of 50 minutes of exercise. Her speed and grade on the treadmill was increased to 2.3 mph and 2.5%, respectively.


Prior to session 28, Ms. Case Study-Angina consulted with her cardiologist. Persistent angina pain while doing everyday activities and exercise precipitated a change from isosorbide mononitrate to ranolazine 500 mg, another type of antianginal medication. As was the case when the dose of isosorbide mononitrate was increased, the practice of administering the sublingual nitroglycerin prior to exercise was eventually discontinued. She was able to exercise at her previous intensity with only minimal symptoms. After completing 36 sessions of CR, Ms. Case Study-Angina went through a post-program evaluation that included an exercise tolerance test and blood work. Her pre- and post-program values are included in Table 10.2.








Table 10.2


Cardiac Rehabilitation Pre/Post-Program Values for Ms. Case Study-Angina




























































CR Entry


CR Exit


% Change


Weight (kg)


64.5


63


−2.3


Waist circumference (cm)


94


91


−3.1


Peak O2 (mL O2 ∙ kg−1 ∙ min−1)


17.5


18.8


+7.5


Stress test treadmill time (min) (Bruce protocol)


6:30


8:45


+18.2


Estimated METs


7


10


+42.9


Total cholesterol (mg/dL)


124


129


+4.0


Triglyceride (mg/dL)


59


64


+8.5


HDL cholesterol (mg/dL)


54


57


+5.6


LDL cholesterol (mg/dL)


58


59


No change


HbA1C (%)


5.9


5.7


−3.4


METs, metabolic equivalents.


On her exit stress test, she was able to increase the exercise duration from 6:30 to 8:45 minutes. Her stress test was stopped due to dyspnea. She experience no scapular angina pain but did have 1/10 chest pressure. Her aerobic fitness improved by 7%. Her peak HR on the exit test was 133 bpm with 1-mm ST-segment depression in leads V2 through V4. Consequently, she was able to work to a higher peak HR on her exit test than at entry (133 vs. 114 bpm) while experiencing fewer anginal symptoms.








Description, Prevalence, and Etiology of Angina Pectoris


Ischemic heart disease is a major public health problem. It is estimated that 1 in 3 adults (about 81 million people) in the United States has some form of ischemic heart disease, including nearly 10 million people with angina pectoris (9). Common symptoms associated with heart disease are angina, dyspnea at rest or at low levels of exertion, orthopnea, peripheral edema, palpitations, dizziness, and syncope. Angina is defined as chest pain, pressure, discomfort, or fullness that is the manifestation of diminished blood flow resulting in inadequate oxygen delivery to the myocardium. Angina is not a disease but rather the symptom of an underlying heart problem. Typically, angina is brought on by exertion or psychological stress and will resolve with rest or medications that induce vasodilatation. Angina-related symptoms may occur in isolation or in combination. Management of symptoms is of paramount importance in the treatment of patients with heart disease and is important reason for referral to CR.


Angina can be a recurring problem or a sudden, acute health concern. Worsening (“crescendo”) angina, sudden-onset angina at rest, and angina lasting more than 15 minutes are symptoms of “unstable” angina. Chronic “stable” angina is usually related to myocardial ischemia. A typical presentation of stable angina occurs following the initiation of physical activity. Generally, symptoms at rest are nonexistent. The anginal symptoms generally resolve with a cessation of activity, a decrease in physical activity intensity, or administration of vasodilator medication.


Education and counseling are important when developing an exercise training program for an individual who experiences chronic, stable angina (9). Patients need to understand and be able to recognize their symptoms. Specifically, patients need to be able to identify the nature of their angina (e.g., location, precipitating factors, associated symptoms, and radiation patterns) and understand that activity patterns need to be adjusted according to the severity of symptoms. It should be clearly communicated to the patient that although experiencing lesser levels of anginal discomfort is acceptable and safe, highly intense pain is to be avoided. Also, reinforcing adherence to medical therapy is of paramount importance. Medications such as β-blockers, nitrates, and calcium channel blockers may influence an individual’s ischemic threshold and should be taken at the prescribed intervals and dose. In addition to the daily prescribed medication, using nitroglycerin prophylactically can be an effective means for an individual to avoid experiencing exercise-induced angina. Taking nitroglycerin about 15 minutes before starting an exercise session may allow a patient to exercise symptom-free at higher workloads than would be possible otherwise.







Case Study 10-2



Mr. Case Study-CABGS


Mr. Case Study-CABGS is a 62-year-old male optometrist. He has a past medical history of asthma, hypertension, and hyperlipidemia. He describes being physically active throughout his typical day but participates in no regular exercise. He presents to his primary care physician with complaints of classic angina symptoms of exertional, substernal chest pain that radiates to the left arm. He was referred for an exercise tolerance test, which was markedly positive with 3- to 4-mm ST-segment depression occurring at 6 minutes on the Bruce protocol. He was immediately put on antianginal medication, lipid-lowering (statin) therapy, and aspirin and was referred for a cardiac catheterization. The catheterization revealed diffuse disease in left main, left anterior descending, left circumflex, and right coronary arteries. His ejection fraction was preserved at 65%. Coronary artery bypass graft surgery (CABGS) was recommended. Surgery included a full sternotomy, a bypass of the left anterior descending artery with the left anterior mammary artery, and saphenous vein grafts to the second obtuse and right coronary arteries. Mr. Case Study-CABGS was in and out of atrial fibrillation during surgery but experienced no serious complications. He did experience atrial fibrillation on post-op day 1. Consequently, metoprolol and warfarin were initiated. By post-op day 5, normal sinus rhythm had been restored, and he was discharged to home.


As an outpatient, his recovery proceeded without complications and he arrived at CR 28 days post-surgery for his baseline consultation and cardiopulmonary exercise tolerance test. He reports that he has been walking for approximately 10 minutes per day. He denies any symptoms other than moderate sternal and saphenous vein-related soreness. His height and weight were 175 cm and 89 kg, respectively. He has lost about 2.5 kg since his surgery, claiming that he does not have much of an appetite. Currently, his BMI is 28, which would categorize him as overweight.


  Waist circumference = 104 cm (41 in)


  Resting ECG: HR is normal sinus rhythm = 64 bpm


  Resting BP: 140/70 mm Hg


  Blood test (preoperative)


  Total cholesterol = 176 mg ∙ dL−1


  Triglyceride = 198 mg ∙ dL−1


  HDL cholesterol = 39 mg ∙ dL−1


  LDL cholesterol = 97 mg ∙ dL−1


  HbA1C = 5.8


Mr. Case Study-CABGS’s medications were reviewed, and his statin therapy was increased from 5 to 20 mg of rosuvastatin to comply with statin therapy treatment guidelines for individuals with a diagnosis of coronary heart disease (17). Otherwise, his medications were held constant and included warfarin, 10 mg of amlodipine, 81 mg of aspirin, and 25 mg of metoprolol.


A cardiopulmonary exercise tolerance test utilizing the Bruce protocol was performed as part of his baseline assessment. He was able to exercise for 3 minutes. His peak HR, O2, and respiratory exchange ratio were 107 bpm, 17.2 mL O2 ∙ kg−1 ∙ min−1, and 1.38, respectively. The exercise ECG revealed no abnormalities, and he denied experiencing any angina-related symptoms. Therefore, he was cleared to begin CR and was instructed to start increasing the duration of his daily walks on non-CR days.


A goal was established for Mr. Case Study-CABGS to increase his daily walking time by 5 minutes each week until he is walking for 30 minutes on nearly all his non-CR days. It was also recommended that he log his activity daily so that it can be reviewed periodically with the CR staff to assess adherence to exercise.


The first session of CR is intended to familiarize the participant with the program, identify goals and objectives, and initiate an individualized exercise training regimen. In consultation with the CR case manager, the following goals for CR were identified for Mr. Case Study-CABGS:


  Improve aerobic fitness and strength.


  Lose weight.


  Lower HbA1C value.


  Lower triglycerides and raise HDL-cholesterol.


A primary goal of the exercise prescription, along with improve aerobic fitness, is to maximize caloric expenditure to promote weight loss (2). Consequently, non–weight-supported exercise is prioritized. Additionally, a dual-action cycle ergometer is selected as an exercise modality because it allows for an upper body activity as he continues to recover from his sternotomy. Table 10.3 has specific information for exercise sessions 1, 3, and 6. Additionally, we tracked his caloric expenditure utilizing the “on-board” displays for the exercise equipment. Caloric expenditure estimates for sessions 1, 3, and 6 were 160, 205, and 230 calories, respectively.








Table 10.3


Cardiac Rehabilitation Exercise Training Summary for Mr. Case Study-CABGS












































































































Treadmill



Session


Weight (kg)


HR (bpm)


BP (mm Hg)


Time


Speed/G


HR/RPE


Combined Arm/Leg Cycle Time/HR


Elliptical Time/HR


Calories Expended


 1


85   


  72


140/70


:25


2.8/2   


    84/12


N/A


:05/88


160


 3


84   


  57


118/84


:25


2.8/3   


    74/11+


:06/79


:05/84


205


 6


84   


  98


140/80


:25


3.0/3   


  120/11+


:08/110


:06/120


230


 9


83   


  84


148/88


:14


:16


3.1/2.5


3.8/2.5


    84/12


  108/15


:12/108


:08/112


320


18


82.5


107


138/80


:14


:16


3.1/2.5


3.8/3.0


  102/12


  108/15


:14/108


:12/104


365


21


82.5


  72


148/88


:14


:16


3.3/3.0


3.8/3.0


    90/12


    96/15


:15/96


:13/94


397


29


81   


102


138/80


:14


:16


3.3/4.0


3.9/4.0


  102/12


  108/15


:14/108


:12/104


425


36


80   


  98


134/80


:14


:16


3.3/4.0


4.0/4.0


    96/12


  102/15


:15/108


:15/106


435


G, grade.

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Feb 15, 2020 | Posted by in SPORT MEDICINE | Comments Off on Special Considerations for Cardiovascular Disease: Chronic Stable Angina and Coronary Artery Bypass Graft Surgery
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