Introduction and importance: Left main coronary artery (LMCA) vasospasm is rare and can cause demand-supply mismatch that can mimic coronary artery disease (CAD). This could lead to misdiagnosis and inappropriate referral for surgical intervention. Case presentation: A 55-year-old woman with no cardiac risk factors presented with anginal chest pain. Vital signs were stable and physical exam was unremarkable. Chest x-ray was normal and electrocardiography (ECG) revealed sinus bradycardia with nonspecific ST-segment and T-wave changes in the inferolateral leads present on prior ECGs. Echocardiography revealed a left ventricular ejection fraction of 60–65% without regional wall motion abnormalities and cardiac troponin was within normal limits. Nuclear stress test was unsuccessful due to severe reaction to regadenoson. Subsequent invasive coronary angiography revealed an isolated 70% stenosis of the LMCA. Patient was referred for surgery, however, coronary computed tomography angiography (CCTA) prior to surgery unmasked spasm and prevented unnecessary surgery. Clinical discussion: Coronary spasm is diagnosed clinically based on typical symptoms, transient ECG changes, and a negative stress test with no regional wall motion abnormalities on echocardiography. During episodes of spasm, coronary angiography would reveal an area of stenosis in the affected coronary segment. This could lead to a misdiagnosis of CAD and, in cases of LMCA stenosis, inappropriate referral for surgical intervention. Conclusion: LMCA spasm is rare but can mimic CAD leading to misdiagnosis and unnecessary surgery. Physicians should have a high suspicion for spasm especially in patients with anginal chest pain who lack CAD risk factors. CCTA can unmask spasm and prevent unnecessary interventions.
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