Guidelines on the Management of Stable Angina Pectoris ... - Cardio

ESC <strong>Guidelines</strong> 19Figure 3 Prognostic angina score. The pattern of angina occurrence can be used to predict prognosis. 80risk of future cardiovascular events than those with a normalECG. 45,264–267 It is possible that in an unselected populationwith stable angina the baseline risk is lower than in many ofthe studies quoted accepting that many of these studieshave been conducted in patients referred for further angiographicevaluation.Recommendations for risk stratification by clinical evaluation,including ECG and laboratory tests in stable anginaClass I(1) Detailed clinical history and physical examinationincluding BMI and/or waist circumference in allpatients, also including a full description of symptoms,quantification of functional impairment, past medicalhistory, and cardiovascular risk profile (level ofevidence B)(2) Resting ECG in all patients (level of evidence B)Risk stratification using stress testingStress testing can take the form of exercise or pharmacologicalstress with or without imaging. Prognostic informationobtained from stress testing relates not just to detectionof ischaemia as a simple binary response, but also theischaemic threshold, the extent and severity of ischaemia(for imaging techniques), and functional capacity (for exercisetesting). Stress testing alone is insufficient to assess riskof future events. In addition to the limitations of the differenttechniques in the detection of myocardial ischaemia,however small, it must also be recognized that ischaemiaper se is not the only factor which influences the likelihoodof acute events. Several lines of evidence have shown thatthe majority of vulnerable plaques appear angiographicallyinsignificant before their rupture, and may not impinge oncoronary flow to reveal characteristic changes during exerciseECG or stress imaging. This may explain the occasionalacute coronary event that occurs shortly after a negativestress test result. Risk stratification with the exercise testshould be a part of a process that includes readily accessibledata from clinical examination and should not take place inisolation. Thus the stress test is performed to provideadditional information regarding the patient’s risk status.Symptomatic patients with suspected or known CAD shouldundergo stress testing to assess the risk of future cardiacevents unless cardiac catheterization is urgently indicated.However, no randomized trials of stress testing have beenpublished, and therefore the evidence base consists ofobservational studies only. The choice of initial stress testshould be based on the patient’s resting ECG, physicalability to perform exercise, local expertise, and availabletechnologies.Exercise ECG. The exercise ECG has been extensively validatedas an important tool in risk stratification in symptomaticpatients with known or suspected coronary disease.The prognosis of patients with a normal ECG and a low clinicalrisk for severe CAD is excellent. In one study in which 37%of outpatients referred for non-invasive testing met thecriteria for low risk 261 fewer than 1% had LM stem arterydisease or died within 3 years. Lower-cost options such astreadmill testing should therefore be used, whenever possible,for initial risk stratification, and only those withabnormal results should be referred to arteriography.The prognostic exercise testing markers include exercisecapacity, blood pressure response, and exercise-inducedischaemia (clinical and ECG). Maximum exercise capacityis a consistent prognostic marker, this measure is at leastpartly influenced by the extent of rest ventricular dysfunctionand the amount of further LV dysfunction induced byexercise. 139,268 However, exercise capacity is also affectedby age, general physical condition, comorbidites, andpsychological state. Exercise capacity may be measured bymaximum exercise duration, maximum MET level achieved,maximum workload achieved in Watts, maximum heart rate,and double (rate–pressure) product. The specific variableused to measure exercise capacity is less important thanthe inclusion of this marker in the assessment. In patientswith known CAD and normal, or mildly impaired LV function,5-year survival is higher in patients with a better exercisetolerance. 123,139,152,269,270Other prognostic exercise testing markers are related toexercise-induced ischaemia and markers include changesin ST-segment (depression or elevation), and exerciseinducedangina. McNeer et al. 270 demonstrated that anearly positive exercise test (ST-depression .1 mm in thefirst two stages of the Bruce protocol) identified a high-riskpopulation, whereas patients who could exercise into stageIV were at low risk regardless of the ST response. ST-segmentelevation is observed most frequently in patients with ahistory of MI; in patients without infarction, ST-elevationduring exercise has been associated with severe transmuralmyocardial ischaemia.In the CASS Registry, 12% of medically treated patientswere identified as high risk on the basis of 0.1 mV ofexercise-induced ST-segment depression and inability tocomplete stage I of the Bruce protocol. These patients hadan average mortality rate of 5% per year. Patients whocould exercise to at least stage III of the Bruce protocolwithout ST changes (34%) constituted the low-risk group(estimated annual mortality, less than 1%). 123Several studies have attempted to incorporate multipleexercise variables into a prognostic score. The clinicalvalue of stress testing is improved considerably by