The absence of evidence is not the evidence of absence: A case report on the challenges in diagnosing ostial left main stenosis.

Because left main (LM) coronary artery stenosis is known to have higher mortality and morbidity compared to lesions in other territories, an early diagnosis and management are crucial to prevent worse outcomes. Due to limitations of coronary angiography (CA), the diagnosis of ostial LM stenosis solely based on CA may result in underdiagnosis of such lesions. Therefore, additional testing is often needed either by pressure wire or intravascular ultrasound (IVUS) to make appropriate diagnosis. We, hereby, present a case of left main ostial stenosis in a 56-year-old male that was missed on multiple coronary angiograms, and highlights many of the considerations in the diagnosis of LM disease.