1. Stress Testing: which test, which patient?
Adam Wolfe, DO
Program Director, IM Residency
Metro Health - University of Michigan Health

2. Conflicts of Interest
NONE

3. Goals Review indications and contraindications for stress testing
Review common modalities for stress evaluation of our patients in the primary care setting
Understand the concern around unnecessary testing
Highlight specific patient populations we commonly encounter
Symptomatic patients
Asymptomatic patients with risk factors
Pre-operative evaluation of non-cardiac surgery
Patients with DM
Cases
Questions and experiences

4. The answers… I don’t have all of the answers.
Stress testing is not indicated in our patients with low CV risk and those without symptoms.
Stress testing is best utilized for our patients with intermediate probability of CVD based on symptoms. Male gender, older age, DM, and dyslipidemia were independent predictors.
Make sure that medical management (GDMT) is optimized – likely this is more effective than stress testing at improving patient outcomes. Continue to fight the good fight against therapeutic inertia.
Pre-operative stress testing is almost never indicated in our patients with good exercise capacity (>4 METS).
When evaluating surgical patients use a validated guideline (RCRI, Gupta, ACS), be consistent about using it, and, trust the one that you use.
At the end of the day, it’s about practicing good medicine.
Fight therapeutic inertia!

5. Our clinical dilemma in primary care
Asked to evaluate patients on a daily basis for CV evaluation
Pre-operative assessment
Patients presenting with chest pain (typical or atypical)
Abnormal ECG results
Patients who want more data to estimate their risk
What data is there for our DM patients and CV screening?
Over the next 30 years, the number of procedures in Medicare patients is expected to double (6  12 million annually)
Studies show that a conservative estimate of overutilization of stress testing in Medicare patients is at 4%
Cardiac complications are the leading cause of death peri-operatively and extend length of stay by an average of 11 days after an event.
The mortality rate of patients with perioperative MI is substantial, ranging from 30% to 50%
This is a really important part of our daily routine in primary care
I mean, DM is a CV equivalent, right?!
A lot of these 30-50% had normal stress tests pre-operatively!
Ann Surg Jan; 257(1): 73–80.

6. Initiatives
Consultative management may increase unnecessary testing and complications with primary care patients.
Ann Intern Med. 2010;152(1):47-51.
Consumer Reports (everyone’s favorite journal) found that 50% of patients polled 1200 people between have had a stress test without symptoms or history of heart disease
Stress testing can cost upwards of $1500 for our patients and can lead to:
-more testing and risk
-unclear results leading to testing dilemmas
-possible harm to our patients
So it makes sense to review data and indications for a commonly considered test

7. Choosing the right test
Review of testing available to us in primary care

8. Indications Patients with symptoms suggesting angina
Patients with acute chest pain (after relief of symptoms)
Patients with recent ACS (treated conservatively) – 3 months
Patients with known CHD and new or worsening symptoms
For the pre-operative evaluation of the non-cardiac surgery patient
Highest risk surgeries (maybe some intermediate)
Patients with chronic LV dysfunction and CHD who are candidates for revascularization
Evaluate severity and symptoms of valvular or congenital heart disease or evaluate arrhythmic therapy (non CAD related)
Asymptomatic patients with multiple risk factors???

9. Contraindications Acute myocardial infarction (MI; within 2 days)
Unstable angina not previously stabilized by medical therapy
Uncontrolled cardiac arrhythmias causing symptoms or hemodynamic compromise
Symptomatic severe aortic stenosis
Uncontrolled symptomatic heart failure
Acute pulmonary embolus or pulmonary infarction
Acute myocarditis or pericarditis
Acute aortic dissection
Gibbons et al., J. Am. Coll. Cardiol. 40;1531, 2002

10. Modalities for Patient Evaluation
Which test?

11. Stress Modalities – Inc HR or Dec Resistance
Exercise (always better, if possible)
Treadmill, Recumbent Bike, Arm Bike
85% max predicted HR is the goal for maximal information
Usual Bruce Protocol starts at 1.7mph at a 10% grade and increases in speed and grade every 3 minutes (4 METS) - Stress test warranty: if you go 10 minutes on a Bruce, you are pretty much guaranteed not to have an event in the next year
3.5 ml/Kg/min O2 consumption = 1 MET
Dobutamine
Positive inotrope and chronotrope (B1) and some vasodilation (B2)
Variable patient response
Increased arrhythmia risk, caution with severe AS
Fewer false positives (vascular sx literature)
Hold Beta blockers/ Diltiazem/Verapamil (48hrs before)

12. Stress Modalities – Inc HR or Dec Resistance
Vasodilator (if your patient can’t exercise)
Adenosine / Dipyridamole
Requires infusion
Regadenoson (Lexiscan)
No infusion needed
Preferred with patients who cannot exercise or who do have LBBB
Contraindication in patients with COPD (caution), hypotension, sick sinus syndrome, high-degree AVB, critical carotid occlusive disease, or oral dypyridamole therapy
Does not rely on regional wall motion abnormalities, as it looks at perfusion
Hold Theophylline, Pentoxifylline (Trental), and Dipyridamole 48 hrs before
Hold all caffeine 12 hrs before
Viagra / Levitra (24hrs before), Cialis (72hrs before), Nitrates (48 hrs before), CCBs (48hrs before)

13. Imaging Modalities
Myocardial imaging evaluation is critical for many patients
Females have significantly increased false + stress ECG results (40-80%)
Echocardiogram
Hemodynamics with stress, wall motion abnormalities, and valve / structural information
Challenging with certain patients
Obesity
COPD or increased AP diameter chest wall
False negatives at times due to decreased afterload
Visual estimation of EF vs calculated EF
Thallium or Sestamibi
Calculated EF based on end systole and end diastole (what if MR or AI)
Provides evidence of under-perfusion
False negatives from left main disease, equal flow limiting obstructions, caffeine consumption
False positive results with hyperventilating or increased soft tissue (breast or abdominal / diaphragm attenuation) – usually inferior territory
If MR or AI, there is a tendency to overestimate EF on nuclear scanning

14. How do they all compare?
Comparison of all modalities available are similar

15. Let’s explore some clinical questions!
3 illustrative cases

16. Sharon
A 45 year old woman with moderate RA affecting hands primarily and mild resting pulmonary hypertension who complaints of chest pain and dyspnea on exertion?
Which stress test is most appropriate?
Exercise EKG
Exercise stress echo
Exercise nuclear
Dobutamine stress echo
Dobutamine nuclear
Vasodilator nuclear
Curbside the cardiologist
Best answer is B, as she is a woman you want to add the imaging modality to improve her predictive value, and evaluate for valvular issues and possibly pulm htn

17. Pre-test probability – test questions
Can the patient exercise to a satisfactory workload?
Does the patient have an abnormal baseline ECG?
Does the patient need an assessment of myocardial viability?
Revascularization strategy
Does the patient have a large body habitus or lung disease?
What is the pre-test likelihood of disease based on the chest pain quality?
What are the costs and effects on health outcomes of each test?
Are there contraindications to the test?

18. Our responsibility
Holy grail: identify patients who are at risk and provide appropriate care and medical optimization
Stress testing identifies patient risk…but pre-test probability is imperative! Bayes Theorem
ACC National Cardiovascular Data Registry patients who underwent coronary angiography: male gender, older age, diabetes mellitus, and hyperlipidemia were independent predictors of the likelihood of CHD
Coronary Artery Surgery Study (CASS), 1465 men and 580 women with complaints of chest pain
Definite angina – Substernal chest discomfort characterized by all of the following characteristics: a typical quality and duration, provocation by exertion or emotional stress, and relief by rest (3/3)
Probable or atypical angina (2/3)
Non-angina or non-ischemic chest pain (0-1/3)
Could other variables help us in our assessment
Coronary calcium scoring has been shown to improve PreTP
We need to know something about the interpretation of the results, even if we aren’t doing the testing.
Optimization of test (max HR, arrhythmias, etc) is important for us to understand
ACC/NCDR patients (more current patient sample) - January 2004 through April 2008, at 663 hospitals in the American College of Cardiology National Cardiovascular Data Registry, we identified patients without known coronary artery disease who were undergoing elective catheterization. The patients' demographic characteristics, risk factors, and symptoms and the results of noninvasive testing were correlated with the presence of obstructive coronary artery disease, which was defined as stenosis of 50% or more of the diameter of the left main coronary artery or stenosis of 70% or more of the diameter of a major epicardial vessel
N Engl J Med. 2010;362(10):886
N Engl J Med. 1979;301(5):230
BMJ 2012;344:e3485

19. Pre-test probability for our patients
Historically Duke Clinical Score and Diamond and Forrester tools tend to overestimate a patient’s pre-test probability for CAD, but still are used widely for estimation of a patient’s risk.
Useful tool for estimation was published by the CAD consortium:
cad-cad-consortium
Validated and easy to use on a rapid basis by you or your MA/RN
8 variables to predict risk – low, intermediate, or high
Extended risk model includes CAC, which isn’t universally performed
BMJ June 12, 344: e3485

20. Into the OR
Evaluation of patient risk pre-operatively with stress testing

21. Vinnie
A 60yo man is evaluated for a pre-operative evaluation prior to a left total knee replacement. He does recently have the complaint of chest pain of 4 months’ duration. He describes the pain as sharp, located in the left chest, with no radiation or associated symptoms, that occurred with walking one to two blocks and resolves with rest. Occasionally, the pain improves with continued walking or occurs during the evening hours. He has hypertension. Family history does not include cardiovascular disease in any first-degree relatives. His only medication is amlodipine.
On physical examination, he is afebrile, blood pressure is 130/80mHg, pulse rate is 72/min, and respiration rate is 12/min. BMI is 28. No carotid bruits are present, and a normal S1 and S2 with no murmurs are heard. Lung fields are clear, and distal pulses are normal. EKG showed normal sinus rhythm.
Is a stress test indicated for Vinnie pre-operatively?

22. Pre-operative evaluation of our patients
JACC 2014 – we have reviewed this before
Evaluate MACE risk for procedure and for patient (using validated tool).
RCRI (Revised Goldman) – 6 indicators
Gupta (NSQIP MICA data) – 5 indicators
ACS (NSQIP data) – 21 indicators
Estimate the functional capacity of the patient.
Will further testing impact decision making or perioperative care?

23. Estimating risk in the office

24. Key piece to consider with our surgical patients
This is the latest ACC/AHA guideline, likely on most of our peripheral brains, whatever that looks like for you.
Low and moderate surgical risk is new – simpler than previous guidelines.

25. To test or not to test, that is the question!
Seven specialty societies recommend against the use of preoperative stress testing in patients scheduled to undergo low- and/or intermediate-risk non-cardiac surgery.
A paradigm shift has occurred for management of most stable CAD with medical therapy first rather than routine PCI.
Significant cost and harm is associated with unnecessary testing, false positives, and additional procedures.
Information from stress testing should be meaningful to direct management
To answer this question, we need to continue to talk with our patients! Determine functional capacity and risk, and focus on the patient’s GDMT and optimize their therapy.
CARP trial – high risk surgical patients show no benefit with revascularization, even with known 70% stenosis.
The challenge with stress testing is that often the lesions that take people out are often the 30-50% lesions, not the 90% lesions!
N Engl J Med 2004;351:

26. What about diabetes?
Do we have data available to help us with our DM patients in our practice?

27. James
A 66 yr old male with diabetes, on dialysis and s/p BKA, admitted with chest pain, and ruled out for MI by EKG and cardiac enzymes, and following up in the office after discharge.
Which stress test is most appropriate?
Exercise EKG
Exercise stress echo
Exercise nuclear
Dobutamine stress echo
Dobutamine nuclear
Vasodilator nuclear
Curbside the cardiologist
Either c,d,e are acceptable.

28. What data do we have for our DM patients?
CV equivalency of DM has been questioned after initial trial data when looking back at meta-analysis
LOOK-AHEAD – 5,783 overweight/obese asymptomatic middle-aged men and women with type 2 diabetes
Only age was a separate determinant of CAD
DADDY-D (Does coronary Atherosclerosis Deserve to be Diagnosed and treated early in Diabetics?) trial. 520 DM patients
They found silent ischemia in 7.6% of patients
Failed to demonstrate a significant reduction in cardiac events and HF episodes
CAC (Coronary Artery Calcium) seems to show significant promise in the risk stratification of DM patients
The yield of MPI can be improved by selecting a higher-risk group of patients with symptoms, peripheral vascular disease, CKD, an abnormal ECG, or a high CAC score (e.g., >400) – if +, think stress testing
N Engl J Med 339:229–
Diabet Med 26:142–
Diabetes Care 33:901–907, 2010

29. What data do we have for our DM patients?
CFR (Coronary Flow Reserve) or FFR (Fractional Flow Reserve) is possibly more representative of CAD risk and mortality in our DM patients.
Equivalent (low) cardiac mortality risk between diabetic patients without known CAD (prior revascularization or MI) but with CFR >1.6 and those without diabetes.
In contrast, the subgroup of diabetic patients without known CAD but with CFR <1.6 had essentially the same risk as patients without diabetes but with CAD.
Murthy et al. from Circularion 2012 – showed that coronary flow reserve (CFR) using positron-emission tomography is a powerful tool that integrates the effects of focal stenosis, diffuse disease, and coronary microvascular function.
Circulation 126:1858–

30. Evaluation of DM patients for CAD
Stress testing in DM patients continues to be an option, with *
CAC seems to be continuing to hold promise as a marker for risk
CACTI (Coronary Artery Calcification in Type 1 Diabetes)
Better when compared with the Framingham risk score and the UKPDS (United Kingdom Prospective Diabetes Study) (area under the curve 0.76, 0.70, and 0.69, respectively; all p < 0.05)
Cardiac CTA has started to provide some evidence for asymptomatic patients with DM
However, coronary CTA is currently not recommended and is not considered appropriate as a risk stratification tool in this population.
Cardiac MR is still investigational, but is gaining some traction, especially in the DM population.
Diabetes Care 26:2923–2928.
J Am Coll Cardiol 43:1663–1669.

31. Rick
A 48 year old 450 lb morbidly obese man with OSA on CPAP and h/o prior DVT, who complaints of atypical chest pain that is relieved with nitroglycerin. He is not very mobile and cannot lie completely flat.
Which stress test is most appropriate?
Exercise EKG
Exercise stress echo
Exercise nuclear
Dobutamine stress echo
Dobutamine nuclear
Vasodilator nuclear
Curbside the cardiologist
Perhaps curbside the cardiologist on this one. Anyone in the room know if a good cardiologist to help answer this clinical dilemma? A stress radionucleotide perfusion (PET imaging study or cardiac MR perfusion study might be helpful. ? Table limits

32. Final Thoughts I still don’t have all of the answers.
Stress testing is not indicated in our patients with low CV risk and those without symptoms.
Stress testing is best utilized for our patients with intermediate probability of CVD based on symptoms. Male gender, older age, DM, and dyslipidemia were independent predictors of risk.
Make sure that medical management (GDMT) is optimized – likely this is more effective than stress testing at improving patient outcomes. Continue to fight the good fight against therapeutic inertia.
Pre-operative stress testing is almost never indicated in our patients with good exercise capacity (>4 METS).
When evaluating surgical patients use a validated guideline (RCRI, Gupta, ACS), be consistent about using it, and, trust the one that you use.
At the end of the day, it’s about practicing good medicine.

33. Thanks! Questions or Experiences?