Stress Testing: Choosing the Right Test for your Patients Sanford J. Gips, M.D., FACC Cardiovascular Associates of the Delaware Valley

Choosing the Best Test What is the patient's pretest risk of CHD?What is the patient's pretest risk of CHD? Exercise vs. PharmacologicExercise vs. Pharmacologic Imaging vs Exercise ECG onlyImaging vs Exercise ECG only How accurate are the alternative tests?How accurate are the alternative tests? Do special considerations make one test more suitable in a specific patient?Do special considerations make one test more suitable in a specific patient?

Exercise ECG Testing vs. Pharmacologic Exercise documents workload that induces ischemiaExercise documents workload that induces ischemia Exercise Capacity and Hemodynamic Response predict prognosis independent of ischemia on imagingExercise Capacity and Hemodynamic Response predict prognosis independent of ischemia on imaging Limited by resting ST changes, LVH, LBBB, paced rhythm, WPWLimited by resting ST changes, LVH, LBBB, paced rhythm, WPW

EKG Criteria in Stress Testing

Non-invasive Testing Modalities EchocardiographyEchocardiography Radionuclide Myocardial Perfusion Imaging (Thallium, Cardiolyte, Myoview)Radionuclide Myocardial Perfusion Imaging (Thallium, Cardiolyte, Myoview) Positron Emission Tomo (PET)Positron Emission Tomo (PET) CT AngiographyCT Angiography

Stress Echo Baseline

Stress Echo After Exercise

Radionuclide Imaging

Stress Echo vs. Radionuclide Perfusion EchoEcho –Higher specificity –More extensive evaluation of anatomy and function –Greater convenience, availability –Lower cost Stress PerfusionStress Perfusion –Higher technical success rate –Higher sensitivity-esp circ disease –Better accuracy when multiple resting wall motion abnormalities present –More extensive published data for gauging prognosis

Questions to consider when ordering a stress test Pre-test probability of CADPre-test probability of CAD Reason for ordering stress testReason for ordering stress test –Suspected CAD –Known CAD to evaluate new symptoms –Known CAD to eval med rx Advantages and limitations of different stress testing modalitiesAdvantages and limitations of different stress testing modalities

Why is Pre-test Probability Important Low pre-test probability (5%)Low pre-test probability (5%) –PPV of +EST only 21% High pre-test probability (90%)High pre-test probability (90%) –PPV of +EST 98%, -EST still 83% chance of CAD Intermed pre-test probab (50%)Intermed pre-test probab (50%) –PPV of +EST 83, -EST decreases likelihood to 36%

Orders on Chest Pain Pts Suspected CAD (r/o CAD/angina)Suspected CAD (r/o CAD/angina) –Don’t order meds that will inhibit ability to obtain adequate stress test (B-blockers, non-DHP Ca++) –Don’t order meds with high toxic/therapeutic ratios for low risk pts (Nitrates) –Do order anti-hypertensive meds (DHP Ca++, ACE-I, diuretics) –Do order anti-platelet rx, anti-coag

Stress Testing in the Setting of Known CAD Purpose in this case is assessing adequacy of medical rxPurpose in this case is assessing adequacy of medical rx Continue cardiac medsContinue cardiac meds Getting HR to >85% not always necessaryGetting HR to >85% not always necessary

Which Stress Test to Order?

Exercise EKG is always preferable if pt can exercise to >85% MPHRExercise EKG is always preferable if pt can exercise to >85% MPHR Pharmacologic if unable to exercise to full capacity, LBBB, abnl ST, LVH, WPWPharmacologic if unable to exercise to full capacity, LBBB, abnl ST, LVH, WPW Dipyridimole or adenosine for most pharmacologic stressDipyridimole or adenosine for most pharmacologic stress Dobutamine only for active wheezing or known prob with persantineDobutamine only for active wheezing or known prob with persantine

Which imaging modality To some degree it is your choiceTo some degree it is your choice Nuc better if likely to have poor echo windows or abnl baseline LV functionNuc better if likely to have poor echo windows or abnl baseline LV function Echo better if time or radiation are important considerationsEcho better if time or radiation are important considerations PET best for obese, most sensitivePET best for obese, most sensitive

Markers of LM or 3-Vessel CAD HypotensionHypotension BradycardiaBradycardia Transient ischemic dilatation (TID)Transient ischemic dilatation (TID) Multiple wall motion abnorm or cavity dilatation on echoMultiple wall motion abnorm or cavity dilatation on echo Ventricular TachycardiaVentricular Tachycardia

Who do I send right to cath? High pre-test probability and classic symptomsHigh pre-test probability and classic symptoms Previously unknown abnormal LV functionPreviously unknown abnormal LV function Recurrent CP with recent negative or equiv stress testRecurrent CP with recent negative or equiv stress test

Take Home Messages Most hospitalized pts will receive imaging stress testingMost hospitalized pts will receive imaging stress testing Exercise EKG is preferable to pharmacologic stress unless pt can’t achieve target HR or has LBBB/pacerExercise EKG is preferable to pharmacologic stress unless pt can’t achieve target HR or has LBBB/pacer Avoid neg chronotropes if stress test is to r/o CADAvoid neg chronotropes if stress test is to r/o CAD

Take Home Messages Nitroglycerin is the most overused, toxic med in the hospitalNitroglycerin is the most overused, toxic med in the hospital Discharge for elective stress testing may be appropriate for low risk patientsDischarge for elective stress testing may be appropriate for low risk patients Catheterization is more cost-effective for high-risk patients or recurrent chest pain despite negative studiesCatheterization is more cost-effective for high-risk patients or recurrent chest pain despite negative studies