What is the diagnosis and management plan for a patient with a left ventricular ejection fraction (LVEF) of 46%, septal and inferior wall hypokinesis, and Single Photon Emission Computed Tomography (SPECT) images showing reversible ischemic defects, particularly with a large reversible anterior defect and basilar inferior defects, in the absence of significant coronary artery calcifications?

Diagnosis and Management of Reversible Ischemia with Reduced LVEF

Primary Diagnosis

This patient has significant coronary artery disease with reversible myocardial ischemia affecting multiple territories (large anterior and basilar inferior defects) and mild-to-moderate left ventricular systolic dysfunction (LVEF 46%). The attenuation-corrected (AC) images are more reliable than non-AC images for identifying true ischemia, and the large reversible anterior defect combined with basilar inferior reversibility indicates high-risk, likely multivessel coronary disease 1.

Critical Interpretation Points

SPECT Findings Analysis

• The attenuation-corrected images should guide clinical decision-making over non-AC images, as the fixed inferior defect on non-AC images likely represents diaphragmatic attenuation artifact rather than true infarction 1.

• Large reversible anterior defect (>10% of LV) carries significant prognostic information and is associated with increased risk of cardiac death and all-cause mortality 1.

• The combination of reversible defects in multiple territories with LVEF of 46% indicates high-risk anatomy, likely left anterior descending (LAD) and right coronary artery (RCA) or left circumflex (LCX) disease 1, 2.

• Septal and inferior wall hypokinesis with reversible defects suggests viable but ischemic myocardium that may benefit from revascularization 1.

LVEF Considerations

• LVEF of 46% falls into the mildly reduced category (40-49%) and represents heart failure with mildly reduced ejection fraction (HFmrEF) 3.

• The absence of significant coronary calcifications does NOT exclude obstructive coronary disease, particularly in younger patients or those with soft plaque 1.

Immediate Management Algorithm

Step 1: Coronary Angiography (Mandatory)

Proceed directly to invasive coronary angiography without additional noninvasive testing 1. The rationale includes:

• Patients with large areas of reversible ischemia (>10% of LV) and reduced LVEF are candidates for revascularization regardless of symptom status 1.

• ACC/AHA guidelines recommend revascularization in patients with significant left main stenosis or large areas of hypoperfused but viable myocardium 1.

• The extent of reversible ischemia demonstrated (large anterior + basilar inferior) suggests multivessel disease requiring anatomic definition 1, 4.

Step 2: Revascularization Strategy

If angiography confirms multivessel disease with viable myocardium:

• Consider coronary artery bypass grafting (CABG) over percutaneous coronary intervention (PCI) for multivessel disease with reduced LVEF, as CABG has demonstrated improved outcomes in this population 1.

• Use fractional flow reserve (FFR) guidance during PCI if this approach is chosen to achieve complete ischemic (not just anatomic) revascularization 1.

• Target complete revascularization of all ischemic territories identified on SPECT imaging 1.

Step 3: Medical Optimization

Initiate guideline-directed medical therapy (GDMT) for heart failure with mildly reduced ejection fraction:

• Beta-blockers (Class I recommendation for HFmrEF) 1.

• ACE inhibitors or ARBs (Class I recommendation) 1.

• Mineralocorticoid receptor antagonists if symptomatic or additional risk factors present 1.

• Statins for coronary disease management 1.

• Antiplatelet therapy (aspirin ± P2Y12 inhibitor depending on revascularization strategy) 1.

High-Risk Features Present

This patient demonstrates multiple high-risk markers that mandate aggressive evaluation and treatment:

• Large reversible anterior defect (>10% of LV) is associated with increased cardiac event rates 1.

• Multivessel ischemic pattern (anterior + inferior territories) suggests LAD and RCA/LCX involvement 1, 4.

• Reduced LVEF (46%) with regional wall motion abnormalities indicates compromised ventricular function that may improve with revascularization 1, 4.

• The combination of extensive ischemia and reduced LVEF predicts short-term benefit from revascularization 1.

Important Clinical Caveats

Avoid These Common Pitfalls

• Do not delay angiography for additional noninvasive testing in patients with this degree of ischemia and reduced LVEF 1.

• Do not assume the fixed inferior defect on non-AC images represents true infarction when AC images show reversibility—this is likely attenuation artifact 1.

• Do not rely on absence of coronary calcification to exclude significant CAD—soft plaque can cause critical stenosis without calcification 1.

• Do not use stress echocardiography to further evaluate for CAD in this patient, as regional wall motion abnormalities are already present at baseline and would confound interpretation 1, 5.

Prognostic Implications

• Normal SPECT MPI predicts low cardiac event rate (1% per year), but this patient has markedly abnormal findings requiring intervention 1.

• Patients with >10% reversible ischemia have significantly higher cardiac death rates compared to those with smaller defects 1.

• Revascularization in patients with viable but ischemic myocardium can favorably affect LV function and potentially improve LVEF 1.

Follow-Up Strategy Post-Revascularization

After successful revascularization:

• Repeat echocardiography at 3-6 months to assess for LVEF improvement and guide heart failure therapy optimization 1.

• Continue GDMT indefinitely even if LVEF improves to >50% 1.

• Consider repeat stress imaging at 1-2 years only if new symptoms develop or to assess completeness of revascularization 1.

• Monitor for development of heart failure symptoms and adjust therapy accordingly 1.