BRIEF REPORT
Cardiac Rehabilitation After Spontaneous Coronary Artery Dissection Taryn C. Silber, BS; Marysia S. Tweet, MD; Melissa J. Bowman, BS; Sharonne N. Hayes, MD; Ray W. Squires, PhD
■ PURPOSE: Although cardiac rehabilitation (CR) improves outcomes in patients after atherosclerotic myocardial infarctions, little is known of the CR benefit among patients with spontaneous coronary artery dissection (SCAD), who are primarily young, otherwise healthy women. The purpose of this study was to describe SCAD patient outcomes in phase 2 outpatient CR. ■ METHODS: Patients with SCAD who enrolled in CR were retrospectively identified. Patients participated in standard CR, which included supervised and independent flexibility, stretching, aerobic, and strength training exercises. Patients received counseling regarding nutrition, weight and stress management. Assessments at baseline and program completion included cardiopulmonary exercise testing or 6-Minute Walk Test, body composition using plethysmography, depression (Patient Health Questionnaire-9), and stress (a scale of 1-10) scores. ■ RESULTS: Nine patients, all women, enrolled in CR an average of 12.3 days (range, 7-21 days) after their SCAD event, with one enrolling again after a recurrence. Cardiac rehabilitation was well received, with participants completing an average of 28 CR sessions (range, 5-39 sessions). Patients did not report cardiac symptoms and there were no adverse events during exercise testing or training. Peak oxygen uptake increased by an average of 18% (n = 4) and 6-minute walk distance increased 22% (n = 4). Average body mass decreased 1.1 kg, fat mass decreased 1.6 kg, and lean mass increased 0.4 kg. Depression and stress scores improved by an average of 2.3 and 1.3 points, respectively. ■ CONCLUSIONS: Standard CR beginning 1 to 2 weeks after SCAD seems to be feasible and safe and results in improved aerobic capacity, body composition, and measures of depression and stress. Because of these benefits, we recommend that patients with SCAD participate in CR.
Cardiac rehabilitation (CR) after myocardial infarction (MI) has been shown to increase survival, improve exercise capacity, and enhance mental health in both men and women of all ages.1 Despite these benefits, participation in CR remains low, particularly among women.2 www.jcrpjournal.com
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W O R D S
cardiac rehabilitation myocardial infarction spontaneous coronary artery dissection women
Author Affiliations: William Beaumont School of Medicine, Oakland University, Rochester, Michigan (Ms Silber); and Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota (Ms Silber, Dr Tweet, Ms Bowman, Dr Hayes, and Dr Squires). The authors declare no conflicts of interest. Correspondence: Ray W. Squires, PhD, 200 First St, SW, Rochester, MN 55905 ([email protected]). DOI: 10.1097/HCR.0000000000000111
Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of MI, and it disproportionately affects young women (>80%, mean age approximately 42 years) with minimal cardiovascular risk factors.3-5 The underlying pathophysiology of SCAD differs from typical atherosclerotic disease as it CR After SCAD / 1
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involves tearing or splitting of the coronary artery walls and/or intramural hematoma formation.4 As such, SCAD has been associated with conditions related to weakened blood vessel walls such as peripartum state, fibromuscular dysplasia, or connective tissue dysplasias and possibly triggered by extreme emotion or exercise.4-6 Because of both its underrecognition and relative rarity as a cause of MI, the pathophysiology, natural history, and optimal treatment strategies remain poorly understood. Recent reports suggest that SCAD is far more common than previously thought. It is the most common cause of pregnancy-associated MI7 and may account for 10% to 24% of MIs in women younger than 50 years.8-10 Optimal management of acute SCAD and recommendations for long-term followup remain uncertain.3,4 SCAD recurrence rates are substantial,4 and symptoms of depression and anxiety are common.6 Likewise, although current recommendations indicate CR for all patients with MI regardless of the underlying etiology,11 there is an inherent reluctance for patients with SCAD to be referred to CR because of (1) young age without traditional risk factors and no foreseeable CR benefit and (2) concern that CR exercise training is unsafe or may prompt a recurrent SCAD. Participation of patients with SCAD in CR has been previously reported in one single case.12 Therefore, the purpose of this study was to report our experience with a small series of patients with SCAD who have been treated in our standard CR program. We hypothesized that CR participation by patients with SCAD would result in improved short-term outcomes.
METHODS This study was approved by the Mayo Foundation Institutional Review Board, and all patients provided authorization for use of their medical records for research purposes as required by Minnesota law. Demographics, potential etiologic associations, clinical presentation, coronary distribution, treatment modality, and in-hospital and short-term outcomes were determined by medical record and angiographic review, and clinical and CR followup.
Study Population All patients with a confirmed SCAD MI who participated in the Mayo Clinic CR program between April 2008 and June 2014 were identified retrospectively and included in this study. Cardiac rehabilitation typically began within 1 to 2 weeks after hospital discharge. All patients were
assigned a case manager who guided them through the rehabilitation process. Assessments at baseline and at program completion included aerobic exercise capacity quantified by either cardiopulmonary exercise testing with direct measurement of peak oxygen uptake (V˙O2peak) or 6-minute walk distance; body composition using BOD POD® air displacement plethysmography (COSMED, Rome, Italy); depression (Patient Health Questionnaire-9, PHQ-913); and emotional stress (subjective rating from 1 to 10).
Outpatient CR Program Program components included 1 to 3 supervised exercise sessions per week. Flexibility/stretching exercises were performed before and after aerobic exercise training. Aerobic exercise intensity was prescribed at 60% to 70% of heart rate reserve and/or ratings of 12 to 14 on the Borg rating of perceived exertion (RPE) scale,14 with a duration goal of 30 to 45 minutes plus 5 minutes of both aerobic warm-up and cool-down consisting of walking on a track. When patients were able to exercise 20 continuous minutes at the prescribed intensity (typically after the fourth to sixth sessions), high-intensity aerobic interval training was introduced. Three to 5 high-intensity intervals (RPE, 15-17) lasting 60 to 120 seconds interspersed with moderate-intensity intervals (RPE, 12-14) were prescribed during 2 or 3 of the supervised exercise sessions per week. Modes of aerobic exercise for patients with SCAD included treadmill walking/ jogging, cycle ergometry, and elliptical trainer. Independent moderate-intensity aerobic exercise (usually walking) was prescribed with a goal of 30-plus minutes at least 2 to 3 days per week. Strength training using free weights, weight machines, and stability ball was prescribed. Strength training typically required 10 to 20 minutes with 8 to 15 repetitions, intensity of RPE 12 to 14, 1 to 2 sets per muscle group (upper and lower extremities, core muscles). In addition, patients received education and counseling regarding healthy nutrition, weight control, and stress management via written materials, videos, cooking class, and one-on-one consultations with a registered dietitian, registered nurse, or case manager. Data are reported using descriptive statistics only because of the small number of subjects.
RESULTS Nine female patients with SCAD who participated in CR were identified. One of these patients participated in CR on 2 separate occasions because of recurrent SCAD, which occurred 27 months after the initial
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event. Patient characteristics are summarized in Table 1. Average age at the incident SCAD was 47 years (range: 35-55 years). All initial events were single-vessel SCAD and most presented with a nonST-elevation MI although one presented with ST elevation MI and ventricular fibrillation cardiac arrest. Only one patient was taking aspirin before SCAD. Medications during CR participation included aspirin (9 patients), thienopyridine (5 patients), statin (4 patients), β-blocker (6 patients), angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (4 patients), and calcium channel blocker (2 patients). Overall, CR was well-received. Patients did not report cardiac symptoms, and there were no adverse events during exercise testing or training. Average number of sessions attended was 28 (range: 5-39 sessions) starting at an average of 12.3 days (range: 7-21 days) after the SCAD event. The patient who
attended only 5 sessions was an avid athlete and elected to conduct most exercise independent of CR supervision. This patient completed most of the baseline and part of the program completion assessments. Among the 4 participants with complete pre- and postcardiopulmonary exercise testing data, V˙O2peak increased by an average of 4.4 mL/kg/min (18%, Table 2), and the average increase in 6-minute walk distance was 22%. Changes in body composition included 1.1 kg reduction in body mass, 1.6 kg reduction in fat mass, and 0.4 kg increase in lean mass. Among 7 patients, mean PHQ-9 depression scores were reduced by an average of 2.3 points by program completion. Of the patients reporting both pre- and post-CR stress scores (1-10; low to high stress; n = 6), the average reduction in stress post-CR was 1.3 points. Participants attributed their decreased stress levels to the ability to exercise in a controlled and monitored
T a b l e 1 • Individual Patient Baseline Characteristics Patient
1
2
3
4
5
6
7
8
9a
Age at event, y
45
55
35
54
45
54
48
52
First: 38 Second: 41
BMI, kg/m2
21.6
22.8
24.1
28.5
25.2
34.4
35.8
33.0
27.4
HTN
Yes
Yes
No
Yes
No
No
Yes
No
Yes
HLD
Yes
Yes
No
Yes
No
No
Yes
Yes
Yes
FMD
Yes
Yes
No
No
No
No
No
Not screened
No (limited screen)
Former tobacco useb
Yes
Yes
No
Yes
No
No
No
No
Yes
History of depression
No
Yes
No
No
Yes
Yes
No
No
No
Connective tissue dysplasia
No
No
No
No
Vascular EhlersDanlos
No
No
No
No
NSTEMI
NSTEMI
NSTEMI
NSTEMI
NSTEMI
NSTEMI
STEMI; Vfib arrest
First: NSTEMI Second: STEMI
Presentation
NSTEMI
Acute treatment
Successful PCI with 3 DES
CT
CT
CT
CT
CT
CT
Successful PCI with 3 DES
First: CT Second: CT
67
60
64
70
60
65
30
60
First: 50 Second: 61
LAD
OM
LAD
OM
RCA
OM
OM
RCA
First: LAD, Second: OM and diagonal
Time from SCAD to CR, d
11
8
7
21
12
17
9
9
First: 14 Second: 15
Recurrence
No
No
No
No
No
No
No
No
Yes
Post-SCAD LVEF, % SCAD location
Abbreviations: BMI, body mass index; CR, cardiac rehabilitation; CT, conservative therapy; DES, drug-eluting stent; FMD, fibromuscular dysplasia; HLD, hyperlipidemia; HTN, hypertension; LAD, left anterior descending coronary artery; LVEF, left ventricular ejection fraction; NSTEMI, non-ST elevation myocardial infarction; OM, first obtuse marginal branch of left circumflex coronary artery; PCI, percutaneous coronary intervention; RCA, right coronary artery; SCAD, spontaneous coronary artery dissection; STEMI, ST-elevation myocardial infarction; Vfib, ventricular fibrillation. a
The patient had 2 SCAD events, designated as first and second, and she participated in cardiac rehabilitation twice.
b
At the time of SCAD event, no patients were using tobacco.
Notes: None of the patients were peripartum or had a history of diabetes mellitus, postmenopausal hormone therapy, or fertility treatment. None identified extreme emotion or exercise as triggers for SCAD. All events (except for the patient with a recurrence) were single-vessel SCAD.
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CR After SCAD / 3
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T a b l e 2 • CR Program-Selected Outcomes for Individual Patients Patient
1a
2
3
4
5
6
7
8
9
9b
Mean ± SDc
CR Sessions, n
5
36
35
28
29
32
15
39
33
28
28 ± 10.4
V˙ O2peak, mL/kg/min
32.1
26.7
22.7
23.1
−
−
−
−
–
22.6
25.4 ± 4.1
V˙O2peak, % predicted
108
104
67
88
−
−
−
−
–
72
87.8 ± 18.4
6MWT, m
717
−
−
−
359
405
−
671
616
−
553.6 ± 161.5
6MWT, % predicted
114
−
−
−
60
89
−
127
102
−
98.4 ± 25.7
Body mass, kg
63.4
59.5
65.3
82.6
59.0
90.5
93.3
−
74.4
77.2
73.9 ± 13.0
Fat mass, kg
19.7
17.7
23.5
37.1
17.0
43.5
38.9
−
30.3
33.1
29.0 ± 9.9
Body fat, %
31.0
29.8
36.0
44.9
29.0
48.1
41.8
−
40.8
42.9
38.3 ± 7.0
Lean mass, kg
43.7
41.8
41.8
45.5
42.0
47.0
54.3
−
41.1
44.1
44.6 ± 4.1
Emotional stress rating
−
5
3
5
10
4
9
−
−
7
6.1 ± 2.6
PHQ-9
0
4
4
3
10
11
0
4
−
3
4.3 ± 3.8
V˙O2peak, mL/kg/min
−
29.1
29.3
23.2
−
−
−
−
−
31.1
28.2 ± 3.0
V˙O2peak, % predicted
−
114
87
89
−
−
−
−
−
99
97.3 ± 10.1
6MWT, m
−
−
−
−
564
469
−
793
677
−
625.8 ± 121.4
102
−
148
113
−
114.0 ± 20.9
−
73.7
73.0
70.4 ± 11.0
28.0
27.3 ± 9.7
Pre-CR
Post-CR
6MWT, % predicted
−
−
−
−
93
65.0
58.6
65.0
82.7
57.1
87.7
Fat mass, kg
−
15.1
22.9
37.4
17.1
40.7
−
−
30.0
Body fat, %
−
25.7
35.2
45.2
29.8
46.4
−
−
40.7
38.4
37.3 ± 7.7
Lean mass, kg
−
43.5
42.1
45.3
40.0
47.0
−
-
43.7
44.9
43.8 ± 2.3
Emotional stress rating
−
6
1
5
5
3
−
−
−
6
4.3 ± 2.0
PHQ-9
−
4
4
5
5
0
−
2
−
3
3.3 ± 1.8
V˙O2peak, mL/kg/min
−
2.4
6.6
0.1
−
−
−
−
−
8.5
4.4 ± 3.8
V˙O2peak, % predicted
−
10.0
20.0
1.0
−
−
−
−
−
27
14.5 ± 11.4
6MWT, m
−
−
−
−
205
69
−
122
61
−
114.3 ± 66.3
6MWT, % predicted
−
−
−
−
1
13
−
21
11
−
11.5 ± 8.2
+1.6
−0.9
−0.3
+0.1
−1.9
−2.7
−
−
−0.7
−4.2
−1.1 ± 1.8
Fat mass, kg
−
−2.6
−0.6
+0.3
+0.1
−2.8
−
−
−0.3
−5.1
−1.6 ± 2.0
Body fat, %
−
−4.1
−0.8
+0.3
+0.8
−1.7
−
−
−0.1
−4.5
−1.4 ± 2.1
Lean mass, kg
−
+1.6
+0.3
−0.2
−2.0
0
−
−
+2.6
+0.8
0.4 ± 1.5
Emotional stress rating
−
+1
−2
0
−5
−1
−
−
−
−1
−1.3 ± 2.1
PHQ-9
−
0
0
+2
−5
−11
−
−2
−
0
−2.3 ± 4.4
Body mass, kg
−
Pre- and post-CR changec
Body mass, kg
˙ O2, oxygen uptake; 6MWT, 6-Minute Walk Test. Abbreviations: CR, cardiac rehabilitation; PHQ-9, Patient Health Questionnaire-9; V a
The patient was an avid athlete and elected to conduct most exercise independent of CR supervision.
b
The patient experienced 2 spontaneous coronary artery dissection events and participated in CR twice.
c
Only those who had pre- and postrehab data available were included in the mean and change calculations.
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environment and participation in sessions on preventative health topics, including diet, exercise, and mental health. Of the 4 patients asked, 3 (75%) indicated that outpatient CR provided both emotional and physical health benefits.
DISCUSSION This study is the first to report that, despite a different underlying mechanism for MI, patients with SCAD benefited from standard CR initiated 1 to 2 weeks after MI with demonstrable improvement in V˙O2peak, 6-minute walk distance, body composition, and mental health indices. The CR exercise training sessions and exercise tests were well tolerated and without cardiac symptoms or adverse events. After MI, CR participation has been previously shown to improve overall mental health, particularly depression, in participants across a wide range of demographics.1,15 Although most participants in the current study were not or only mildly depressed, as indicated by low initial PHQ-9 scores, they had overall improvement in mental health scores. As many as one-third of patients with SCAD experience symptoms of depression and/or anxiety, especially if they are younger and peripartum, emphasizing the importance of CR in this cohort of patients.16 We have observed that some patients referred to the Mayo Clinic SCAD Clinic have been dissuaded by their local providers from even minimal physical exertion, such as lifting greater than 5 lb or participation in CR, because of the association between SCAD and extreme exertion. If applied over a lifetime, these restrictions may substantially increase the risk of other conditions including osteoporosis, obesity, and atherosclerosis. Therefore, similar to other high-risk patient groups, our practice has been to enroll patients with SCAD in CR, which provides them with a medically supervised environment in which to initiate exercise after MI. The present study emphasizes the mental and physiological benefits of CR and underscores the importance of health care providers recognizing and strongly encouraging young, female cardiac patients, particularly patients with SCAD, to participate in CR. Further research is needed on the role of CR in the management of SCAD. Because of the relatively low number of patients with SCAD, a multicenter study will be required to enroll an adequate number of patients to fully address the questions of safety and psychosocial benefits. In addition, longer-term followup of patients who complete CR is needed to assess important outcomes, such as recurrence of www.jcrpjournal.com
SCAD and the ability of patients to continue with therapeutic lifestyle changes.
Limitations The primary limitation of this study was the small sample size. Spontaneous coronary artery dissection is a relatively uncommon cause of MI and the diagnosis may be missed so this cohort may not represent all patients with SCAD who participated in our CR program. Other limitations were the lack of a usual care group who did not participate in CR and the retrospective nature of the study. Also, there was variation in the baseline and program completion assessments (ie, not all variables were assessed in all patients). Finally, there was variability in the number of CR sessions completed by the patients. Regardless of these limitations, this study emphasizes the importance of further investigating CR for patients after SCAD.
CONCLUSIONS Standard CR beginning 1 to 2 weeks after SCAD seems to be feasible and safe and may result in improved aerobic capacity, body composition, and overall mental health. Therefore, we recommend that patients with SCAD be encouraged to participate in CR.
References 1. Dunlay SM, Witt BJ, Allison TG, et al. Barriers to participation in cardiac rehabilitation. Am Heart J. 2009;158(5):852-859. 2. Sanderson B, Shewchuk R, Bittner V. Cardiac rehabilitation and women: what keeps them away? J Cardiopulm Rehabil Prev. 2010;30(1):12-21. 3. Hayes SN. Spontaneous coronary artery dissection (SCAD): new insights into this not-so-rare condition. Tex Heart Inst J. 2014;41(3):295-298. 4. Tweet MS, Hayes SN, Pitta SR, et al. Clinical features, management, and prognosis of spontaneous coronary artery dissection. Circulation. 2012;126(5):579-588. 5. Saw J, Ricci D, Starovoytov A, Fox R, Buller CE. Spontaneous coronary artery dissection: prevalence of predisposing conditions including fibromuscular dysplasia in a tertiary center cohort. J Am Coll Cardiol Int. 2013;6(1):44-52. 6. Liang JJ, Prasad M, Tweet MS, et al. A novel application of CT angiography to detect extracoronary vascular abnormalities in patients with spontaneous coronary artery dissection. J Cardiovasc Comput Tomogr. 2014;8(3):189-197. 7. Elkayam U, Jalnapurkar S, Barakkat MN, et al. Pregnancyassociated acute myocardial infarction: a review of contemporary experience in 150 cases between 2006 and 2011. Circulation. 2014;129(16):1695-1702. 8. Nishiguchi T, Tanaka A, Ozaki Y, et al. Prevalence of spontaneous coronary artery dissection in patients with acute coronary syndrome [published online ahead of print September 11, 2013]. Eur Heart J Acute Cardiovasc Care. 2013. doi:10.1177/2048872613504310.
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9. Vanzetto G, Berger-Coz E, Barone-Rochette G, et al. Prevalence, therapeutic management and medium-term prognosis of spontaneous coronary artery dissection: results from a database of 11,605 patients. Eur J Cardiothorac Surg. 2009;35:250-254. 10. Saw J, Aymong E, Mancini GBJ, Sedlak T, Starovoytov A, Ricci D. Nonatherosclerotic coronary artery disease in young women. Can J Cardiol. 2014;30(7):814-819. 11. American Association of Cardiovascular and Pulmonary Rehabilitation. Guidelines for Cardiac Rehabilitation and Secondary Prevention Programs. 5th ed. Champaign, IL: Human Kinetics; 2013. 12. Pinto M, Camargo R, Filho JC, et al. Influence of cardiac rehabilitation in primigravida with spontaneous coronary artery
13. 14. 15.
16.
dissection during postpartum. Int Arch Med. 2014;7 (1):20. Kroenke K, Spitzer RL, Williams JBW. The PHQ-9. J Gen Intern Med. 2001;16(9):606-13. Borg G. Borg’s Perceived Exertion and Pain Scales. 1st ed. Champaign, IL: Human Kinetics; 1998. Milani RV, Lavie CJ. Impact of cardiac rehabilitation on depression and its associated mortality. Am J Med. 2007;120(9): 799-806. Liang JJ, Tweet MS, Hayes SE, Gulati R, Hayes SN. Prevalence and predictors of depression and anxiety among survivors of myocardial infarction due to spontaneous coronary artery dissection. J Cardiopulm Rehabil Prev. 2014;34(2):138-142.
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Cardiac Rehabilitation After Spontaneous Coronary Artery Dissection Taryn C. Silber, BS; Marysia S. Tweet, MD; Melissa J. Bowman, BS; Sharonne N. Hayes, MD; Ray W. Squires, PhD
■ PURPOSE: Although cardiac rehabilitation (CR) improves outcomes in patients after atherosclerotic myocardial infarctions, little is known of the CR benefit among patients with spontaneous coronary artery dissection (SCAD), who are primarily young, otherwise healthy women. The purpose of this study was to describe SCAD patient outcomes in phase 2 outpatient CR. ■ METHODS: Patients with SCAD who enrolled in CR were retrospectively identified. Patients participated in standard CR, which included supervised and independent flexibility, stretching, aerobic, and strength training exercises. Patients received counseling regarding nutrition, weight and stress management. Assessments at baseline and program completion included cardiopulmonary exercise testing or 6-Minute Walk Test, body composition using plethysmography, depression (Patient Health Questionnaire-9), and stress (a scale of 1-10) scores. ■ RESULTS: Nine patients, all women, enrolled in CR an average of 12.3 days (range, 7-21 days) after their SCAD event, with one enrolling again after a recurrence. Cardiac rehabilitation was well received, with participants completing an average of 28 CR sessions (range, 5-39 sessions). Patients did not report cardiac symptoms and there were no adverse events during exercise testing or training. Peak oxygen uptake increased by an average of 18% (n = 4) and 6-minute walk distance increased 22% (n = 4). Average body mass decreased 1.1 kg, fat mass decreased 1.6 kg, and lean mass increased 0.4 kg. Depression and stress scores improved by an average of 2.3 and 1.3 points, respectively. ■ CONCLUSIONS: Standard CR beginning 1 to 2 weeks after SCAD seems to be feasible and safe and results in improved aerobic capacity, body composition, and measures of depression and stress. Because of these benefits, we recommend that patients with SCAD participate in CR.
Cardiac rehabilitation (CR) after myocardial infarction (MI) has been shown to increase survival, improve exercise capacity, and enhance mental health in both men and women of all ages.1 Despite these benefits, participation in CR remains low, particularly among women.2 www.jcrpjournal.com
K E Y
W O R D S
cardiac rehabilitation myocardial infarction spontaneous coronary artery dissection women
Author Affiliations: William Beaumont School of Medicine, Oakland University, Rochester, Michigan (Ms Silber); and Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota (Ms Silber, Dr Tweet, Ms Bowman, Dr Hayes, and Dr Squires). The authors declare no conflicts of interest. Correspondence: Ray W. Squires, PhD, 200 First St, SW, Rochester, MN 55905 ([email protected]). DOI: 10.1097/HCR.0000000000000111
Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of MI, and it disproportionately affects young women (>80%, mean age approximately 42 years) with minimal cardiovascular risk factors.3-5 The underlying pathophysiology of SCAD differs from typical atherosclerotic disease as it CR After SCAD / 1
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JCRP-D-14-00139_LR 1
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involves tearing or splitting of the coronary artery walls and/or intramural hematoma formation.4 As such, SCAD has been associated with conditions related to weakened blood vessel walls such as peripartum state, fibromuscular dysplasia, or connective tissue dysplasias and possibly triggered by extreme emotion or exercise.4-6 Because of both its underrecognition and relative rarity as a cause of MI, the pathophysiology, natural history, and optimal treatment strategies remain poorly understood. Recent reports suggest that SCAD is far more common than previously thought. It is the most common cause of pregnancy-associated MI7 and may account for 10% to 24% of MIs in women younger than 50 years.8-10 Optimal management of acute SCAD and recommendations for long-term followup remain uncertain.3,4 SCAD recurrence rates are substantial,4 and symptoms of depression and anxiety are common.6 Likewise, although current recommendations indicate CR for all patients with MI regardless of the underlying etiology,11 there is an inherent reluctance for patients with SCAD to be referred to CR because of (1) young age without traditional risk factors and no foreseeable CR benefit and (2) concern that CR exercise training is unsafe or may prompt a recurrent SCAD. Participation of patients with SCAD in CR has been previously reported in one single case.12 Therefore, the purpose of this study was to report our experience with a small series of patients with SCAD who have been treated in our standard CR program. We hypothesized that CR participation by patients with SCAD would result in improved short-term outcomes.
METHODS This study was approved by the Mayo Foundation Institutional Review Board, and all patients provided authorization for use of their medical records for research purposes as required by Minnesota law. Demographics, potential etiologic associations, clinical presentation, coronary distribution, treatment modality, and in-hospital and short-term outcomes were determined by medical record and angiographic review, and clinical and CR followup.
Study Population All patients with a confirmed SCAD MI who participated in the Mayo Clinic CR program between April 2008 and June 2014 were identified retrospectively and included in this study. Cardiac rehabilitation typically began within 1 to 2 weeks after hospital discharge. All patients were
assigned a case manager who guided them through the rehabilitation process. Assessments at baseline and at program completion included aerobic exercise capacity quantified by either cardiopulmonary exercise testing with direct measurement of peak oxygen uptake (V˙O2peak) or 6-minute walk distance; body composition using BOD POD® air displacement plethysmography (COSMED, Rome, Italy); depression (Patient Health Questionnaire-9, PHQ-913); and emotional stress (subjective rating from 1 to 10).
Outpatient CR Program Program components included 1 to 3 supervised exercise sessions per week. Flexibility/stretching exercises were performed before and after aerobic exercise training. Aerobic exercise intensity was prescribed at 60% to 70% of heart rate reserve and/or ratings of 12 to 14 on the Borg rating of perceived exertion (RPE) scale,14 with a duration goal of 30 to 45 minutes plus 5 minutes of both aerobic warm-up and cool-down consisting of walking on a track. When patients were able to exercise 20 continuous minutes at the prescribed intensity (typically after the fourth to sixth sessions), high-intensity aerobic interval training was introduced. Three to 5 high-intensity intervals (RPE, 15-17) lasting 60 to 120 seconds interspersed with moderate-intensity intervals (RPE, 12-14) were prescribed during 2 or 3 of the supervised exercise sessions per week. Modes of aerobic exercise for patients with SCAD included treadmill walking/ jogging, cycle ergometry, and elliptical trainer. Independent moderate-intensity aerobic exercise (usually walking) was prescribed with a goal of 30-plus minutes at least 2 to 3 days per week. Strength training using free weights, weight machines, and stability ball was prescribed. Strength training typically required 10 to 20 minutes with 8 to 15 repetitions, intensity of RPE 12 to 14, 1 to 2 sets per muscle group (upper and lower extremities, core muscles). In addition, patients received education and counseling regarding healthy nutrition, weight control, and stress management via written materials, videos, cooking class, and one-on-one consultations with a registered dietitian, registered nurse, or case manager. Data are reported using descriptive statistics only because of the small number of subjects.
RESULTS Nine female patients with SCAD who participated in CR were identified. One of these patients participated in CR on 2 separate occasions because of recurrent SCAD, which occurred 27 months after the initial
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event. Patient characteristics are summarized in Table 1. Average age at the incident SCAD was 47 years (range: 35-55 years). All initial events were single-vessel SCAD and most presented with a nonST-elevation MI although one presented with ST elevation MI and ventricular fibrillation cardiac arrest. Only one patient was taking aspirin before SCAD. Medications during CR participation included aspirin (9 patients), thienopyridine (5 patients), statin (4 patients), β-blocker (6 patients), angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (4 patients), and calcium channel blocker (2 patients). Overall, CR was well-received. Patients did not report cardiac symptoms, and there were no adverse events during exercise testing or training. Average number of sessions attended was 28 (range: 5-39 sessions) starting at an average of 12.3 days (range: 7-21 days) after the SCAD event. The patient who
attended only 5 sessions was an avid athlete and elected to conduct most exercise independent of CR supervision. This patient completed most of the baseline and part of the program completion assessments. Among the 4 participants with complete pre- and postcardiopulmonary exercise testing data, V˙O2peak increased by an average of 4.4 mL/kg/min (18%, Table 2), and the average increase in 6-minute walk distance was 22%. Changes in body composition included 1.1 kg reduction in body mass, 1.6 kg reduction in fat mass, and 0.4 kg increase in lean mass. Among 7 patients, mean PHQ-9 depression scores were reduced by an average of 2.3 points by program completion. Of the patients reporting both pre- and post-CR stress scores (1-10; low to high stress; n = 6), the average reduction in stress post-CR was 1.3 points. Participants attributed their decreased stress levels to the ability to exercise in a controlled and monitored
T a b l e 1 • Individual Patient Baseline Characteristics Patient
1
2
3
4
5
6
7
8
9a
Age at event, y
45
55
35
54
45
54
48
52
First: 38 Second: 41
BMI, kg/m2
21.6
22.8
24.1
28.5
25.2
34.4
35.8
33.0
27.4
HTN
Yes
Yes
No
Yes
No
No
Yes
No
Yes
HLD
Yes
Yes
No
Yes
No
No
Yes
Yes
Yes
FMD
Yes
Yes
No
No
No
No
No
Not screened
No (limited screen)
Former tobacco useb
Yes
Yes
No
Yes
No
No
No
No
Yes
History of depression
No
Yes
No
No
Yes
Yes
No
No
No
Connective tissue dysplasia
No
No
No
No
Vascular EhlersDanlos
No
No
No
No
NSTEMI
NSTEMI
NSTEMI
NSTEMI
NSTEMI
NSTEMI
STEMI; Vfib arrest
First: NSTEMI Second: STEMI
Presentation
NSTEMI
Acute treatment
Successful PCI with 3 DES
CT
CT
CT
CT
CT
CT
Successful PCI with 3 DES
First: CT Second: CT
67
60
64
70
60
65
30
60
First: 50 Second: 61
LAD
OM
LAD
OM
RCA
OM
OM
RCA
First: LAD, Second: OM and diagonal
Time from SCAD to CR, d
11
8
7
21
12
17
9
9
First: 14 Second: 15
Recurrence
No
No
No
No
No
No
No
No
Yes
Post-SCAD LVEF, % SCAD location
Abbreviations: BMI, body mass index; CR, cardiac rehabilitation; CT, conservative therapy; DES, drug-eluting stent; FMD, fibromuscular dysplasia; HLD, hyperlipidemia; HTN, hypertension; LAD, left anterior descending coronary artery; LVEF, left ventricular ejection fraction; NSTEMI, non-ST elevation myocardial infarction; OM, first obtuse marginal branch of left circumflex coronary artery; PCI, percutaneous coronary intervention; RCA, right coronary artery; SCAD, spontaneous coronary artery dissection; STEMI, ST-elevation myocardial infarction; Vfib, ventricular fibrillation. a
The patient had 2 SCAD events, designated as first and second, and she participated in cardiac rehabilitation twice.
b
At the time of SCAD event, no patients were using tobacco.
Notes: None of the patients were peripartum or had a history of diabetes mellitus, postmenopausal hormone therapy, or fertility treatment. None identified extreme emotion or exercise as triggers for SCAD. All events (except for the patient with a recurrence) were single-vessel SCAD.
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T a b l e 2 • CR Program-Selected Outcomes for Individual Patients Patient
1a
2
3
4
5
6
7
8
9
9b
Mean ± SDc
CR Sessions, n
5
36
35
28
29
32
15
39
33
28
28 ± 10.4
V˙ O2peak, mL/kg/min
32.1
26.7
22.7
23.1
−
−
−
−
–
22.6
25.4 ± 4.1
V˙O2peak, % predicted
108
104
67
88
−
−
−
−
–
72
87.8 ± 18.4
6MWT, m
717
−
−
−
359
405
−
671
616
−
553.6 ± 161.5
6MWT, % predicted
114
−
−
−
60
89
−
127
102
−
98.4 ± 25.7
Body mass, kg
63.4
59.5
65.3
82.6
59.0
90.5
93.3
−
74.4
77.2
73.9 ± 13.0
Fat mass, kg
19.7
17.7
23.5
37.1
17.0
43.5
38.9
−
30.3
33.1
29.0 ± 9.9
Body fat, %
31.0
29.8
36.0
44.9
29.0
48.1
41.8
−
40.8
42.9
38.3 ± 7.0
Lean mass, kg
43.7
41.8
41.8
45.5
42.0
47.0
54.3
−
41.1
44.1
44.6 ± 4.1
Emotional stress rating
−
5
3
5
10
4
9
−
−
7
6.1 ± 2.6
PHQ-9
0
4
4
3
10
11
0
4
−
3
4.3 ± 3.8
V˙O2peak, mL/kg/min
−
29.1
29.3
23.2
−
−
−
−
−
31.1
28.2 ± 3.0
V˙O2peak, % predicted
−
114
87
89
−
−
−
−
−
99
97.3 ± 10.1
6MWT, m
−
−
−
−
564
469
−
793
677
−
625.8 ± 121.4
102
−
148
113
−
114.0 ± 20.9
−
73.7
73.0
70.4 ± 11.0
28.0
27.3 ± 9.7
Pre-CR
Post-CR
6MWT, % predicted
−
−
−
−
93
65.0
58.6
65.0
82.7
57.1
87.7
Fat mass, kg
−
15.1
22.9
37.4
17.1
40.7
−
−
30.0
Body fat, %
−
25.7
35.2
45.2
29.8
46.4
−
−
40.7
38.4
37.3 ± 7.7
Lean mass, kg
−
43.5
42.1
45.3
40.0
47.0
−
-
43.7
44.9
43.8 ± 2.3
Emotional stress rating
−
6
1
5
5
3
−
−
−
6
4.3 ± 2.0
PHQ-9
−
4
4
5
5
0
−
2
−
3
3.3 ± 1.8
V˙O2peak, mL/kg/min
−
2.4
6.6
0.1
−
−
−
−
−
8.5
4.4 ± 3.8
V˙O2peak, % predicted
−
10.0
20.0
1.0
−
−
−
−
−
27
14.5 ± 11.4
6MWT, m
−
−
−
−
205
69
−
122
61
−
114.3 ± 66.3
6MWT, % predicted
−
−
−
−
1
13
−
21
11
−
11.5 ± 8.2
+1.6
−0.9
−0.3
+0.1
−1.9
−2.7
−
−
−0.7
−4.2
−1.1 ± 1.8
Fat mass, kg
−
−2.6
−0.6
+0.3
+0.1
−2.8
−
−
−0.3
−5.1
−1.6 ± 2.0
Body fat, %
−
−4.1
−0.8
+0.3
+0.8
−1.7
−
−
−0.1
−4.5
−1.4 ± 2.1
Lean mass, kg
−
+1.6
+0.3
−0.2
−2.0
0
−
−
+2.6
+0.8
0.4 ± 1.5
Emotional stress rating
−
+1
−2
0
−5
−1
−
−
−
−1
−1.3 ± 2.1
PHQ-9
−
0
0
+2
−5
−11
−
−2
−
0
−2.3 ± 4.4
Body mass, kg
−
Pre- and post-CR changec
Body mass, kg
˙ O2, oxygen uptake; 6MWT, 6-Minute Walk Test. Abbreviations: CR, cardiac rehabilitation; PHQ-9, Patient Health Questionnaire-9; V a
The patient was an avid athlete and elected to conduct most exercise independent of CR supervision.
b
The patient experienced 2 spontaneous coronary artery dissection events and participated in CR twice.
c
Only those who had pre- and postrehab data available were included in the mean and change calculations.
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environment and participation in sessions on preventative health topics, including diet, exercise, and mental health. Of the 4 patients asked, 3 (75%) indicated that outpatient CR provided both emotional and physical health benefits.
DISCUSSION This study is the first to report that, despite a different underlying mechanism for MI, patients with SCAD benefited from standard CR initiated 1 to 2 weeks after MI with demonstrable improvement in V˙O2peak, 6-minute walk distance, body composition, and mental health indices. The CR exercise training sessions and exercise tests were well tolerated and without cardiac symptoms or adverse events. After MI, CR participation has been previously shown to improve overall mental health, particularly depression, in participants across a wide range of demographics.1,15 Although most participants in the current study were not or only mildly depressed, as indicated by low initial PHQ-9 scores, they had overall improvement in mental health scores. As many as one-third of patients with SCAD experience symptoms of depression and/or anxiety, especially if they are younger and peripartum, emphasizing the importance of CR in this cohort of patients.16 We have observed that some patients referred to the Mayo Clinic SCAD Clinic have been dissuaded by their local providers from even minimal physical exertion, such as lifting greater than 5 lb or participation in CR, because of the association between SCAD and extreme exertion. If applied over a lifetime, these restrictions may substantially increase the risk of other conditions including osteoporosis, obesity, and atherosclerosis. Therefore, similar to other high-risk patient groups, our practice has been to enroll patients with SCAD in CR, which provides them with a medically supervised environment in which to initiate exercise after MI. The present study emphasizes the mental and physiological benefits of CR and underscores the importance of health care providers recognizing and strongly encouraging young, female cardiac patients, particularly patients with SCAD, to participate in CR. Further research is needed on the role of CR in the management of SCAD. Because of the relatively low number of patients with SCAD, a multicenter study will be required to enroll an adequate number of patients to fully address the questions of safety and psychosocial benefits. In addition, longer-term followup of patients who complete CR is needed to assess important outcomes, such as recurrence of www.jcrpjournal.com
SCAD and the ability of patients to continue with therapeutic lifestyle changes.
Limitations The primary limitation of this study was the small sample size. Spontaneous coronary artery dissection is a relatively uncommon cause of MI and the diagnosis may be missed so this cohort may not represent all patients with SCAD who participated in our CR program. Other limitations were the lack of a usual care group who did not participate in CR and the retrospective nature of the study. Also, there was variation in the baseline and program completion assessments (ie, not all variables were assessed in all patients). Finally, there was variability in the number of CR sessions completed by the patients. Regardless of these limitations, this study emphasizes the importance of further investigating CR for patients after SCAD.
CONCLUSIONS Standard CR beginning 1 to 2 weeks after SCAD seems to be feasible and safe and may result in improved aerobic capacity, body composition, and overall mental health. Therefore, we recommend that patients with SCAD be encouraged to participate in CR.
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9. Vanzetto G, Berger-Coz E, Barone-Rochette G, et al. Prevalence, therapeutic management and medium-term prognosis of spontaneous coronary artery dissection: results from a database of 11,605 patients. Eur J Cardiothorac Surg. 2009;35:250-254. 10. Saw J, Aymong E, Mancini GBJ, Sedlak T, Starovoytov A, Ricci D. Nonatherosclerotic coronary artery disease in young women. Can J Cardiol. 2014;30(7):814-819. 11. American Association of Cardiovascular and Pulmonary Rehabilitation. Guidelines for Cardiac Rehabilitation and Secondary Prevention Programs. 5th ed. Champaign, IL: Human Kinetics; 2013. 12. Pinto M, Camargo R, Filho JC, et al. Influence of cardiac rehabilitation in primigravida with spontaneous coronary artery
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