This 55-year-old active female had one prior occurrence of severe chest pain after exertion lasting for 30 minutes. Recently, she had started to experience dyspnea and chest pain while climbing stairs. Her risk factors included a family history of coronary artery disease (CAD), hypercholesterolemia, and a history of taking a COX 2 selective NSAID prescription medication. Stress testing produced mild left chest and arm ache with rapid normalization post-exercise. Nuclear scintigraphy indicated a fixed inferior wall defect with normal wall motion. A coronary angiogram illustrated pressure damping with left main catheter engagement without a clear lesion. A Coronary CTA (CCTA) was performed for further evaluation.
The patient's pre-scan heart rate was 57 beats per minute with normal sinus rhythm. Therefore, no beta-blockers nor nitroglycerine were used. Subsequently an ECG-gated CCTA was performed during the administration of 110 cc of Optiray 350.
The patient was found to have a dominant left coronary system. The left main ostium was stenosed 55% by diameter and 75-80% by area, which accounted for the catheter damping during coronary angiography. The remainder of the left coronary system and the entire right coronary system appeared widely patent with no atherosclerotic changes.
Left Main ostial stenosis can be a life threatening condition in patients with a left dominant system. Sudden occlusion could potentially cause lethal left ventricle ischemia. As noted in this case study, the coronary catheterization performed prior to the CCTA was indeterminate but raised suspicions of ostial stenosis, although catheter-induced spasm could not be excluded. The high resolution CCTA provided noninvasive visualization of the stenotic left main ostium without risk of further traumatic injury. In general, MSCT provides many advantages over catheterization. Catheter damping and spasm, vessel trauma, and dissection are all possible side effects of cardiac catheterization. In order to determine luminal area, intraluminal ultrasound is an additional procedure, which is required. CCTA provides a simple method of visualizing the coronary arteries and determining their luminal areas, while avoiding catheter complications and spasm. It appears that CCTA is more beneficial than cardiac catheterization to evaluate this ostial disease. Further correlation with intraluminal ultrasound can enhance its effectiveness in diagnosis.
The Philips Brilliance CT 40-channel provides a commanding option for the diagnosis of CAD. The system offers 25 mm of coverage during every rotation with sub-isotropic accuracy providing a non-invasive alternative to cardiac catheterization. The workflow and user-friendly cardiac applications simplified the isolation and identification of the stenotic left main ostium. This case highlights the capability of this scanner to diagnose coronary ostial stenosis in patients with angina pectoris. The patient went on to undergo CABG times one with left internal mammary artery to the left anterior descending artery with excellent results. Non-invasive CCTA follow-up of this patient after CABG is also possible.