Читать книгу Practical Cardiovascular Medicine - Elias B. Hanna - Страница 191

Treadmill stress ECG, more specifically the Duke Treadmill Score (DTS), is a powerful risk stratifier. A high-risk DTS implies an increased cardiac mortality and a 75% probability of left main or three-vessel CAD, regardless of imaging results. A low-risk DTS often implies a low mortality; however, ~10% of patients with a low-risk DTS have severe three-vessel or left main disease with a high mortality, and another 10% have two-vessel or proximal LAD disease, and thus, 20% of symptomatic patients with normal stress ECG have significant, high-risk CAD (particularly men).²² These patients are likely to be picked up by stress imaging.^23,24 In fact, a high-risk result on nuclear or echo stress imaging overrules a low- or intermediate-risk result on stress ECG.^23,24 Thus, stress imaging is preferred to stress ECG in patients with a high probability of CAD or with prior coronary revascularization even if ECG is interpretable, while stress ECG is preferred in patients with an intermediate or low CAD probability who are able to walk and have an interpretable baseline ECG (Table 3.1).¹⁸

A high-risk DTS, on the other hand, implies a high risk regardless of imaging results, with a 75% probability of left main or three-vessel CAD and >90% probability of any significant CAD.²² Because of balanced ischemia, some patients with extensive disease have normal or mildly abnormal perfusion imaging but are picked up by ECG variables, DTS, severe angina during testing, and post-stress LV dysfunction. Table 3.2 stratifies the risk according to stress testing.

In patients who have undergone PCI: (i) chest pain relief followed by recurrence months later is typical of in-stent restenosis, or progression of moderate disease outside the stented area (especially in patients who initially presented with ACS); (ii) a persistent chest pain without a pattern of relief and recurrence suggests either non-cardiac pain or residual, non-revascularized disease. The same applies to patients with prior CABG (graft disease instead of in-stent restenosis). Repeat the coronary angiogram if typical angina occurs on mild exertion.