Figure 1.

Clinical Utility of an IDP in Patients With Symptoms and/or Signs of Ischemia But No Obstructive CAD

Two patients with similar baseline angiograms and clinical presentations without obstructive epicardial coronary artery disease (CAD). Each patient undergoes the an interventional diagnostic procedure (IDP), which reveals a distinct diagnosis. Therapies for microvascular and vasospastic angina are distinct and should be guided by the IDP results. The yellow figure shows a typical case of vasospastic angina with preserved microvascular function. The patient was previously on a beta-blocker, and this was substituted for by a calcium-channel blocker with smoking cessation counseling. The blue figure depicts a patient with proven microvascular dysfunction but no severe vasospasm. There were abnormalities in both microcirculatory resistance (index of microcirculatory resistance [IMR]) and coronary vasodilator reserve (coronary flow reserve [CFR]). The patient had a diagnosis of microvascular angina and cessation of long-acting nitrate medication with up-titration of a beta-blocker. The patient underwent cardiac rehabilitation classes to assist in weight loss and identify relevant life-style factors implicated in the condition. Note that some operators may prefer to perform vasoreactivity testing before instrumenting the artery for guidewire based invasive CFR and microvascular resistance measurement. ACEi = angiotensin-converting enzyme inhibitor; angio = angiography; DS = diameter stenosis; ECG = electrocardiography; FFR = fractional flow reserve; GTN = glyceryl trinitrate; rehab = rehabilitation.