A 53-year-old male, ex-smoker, presented with angina on exertion class II for the past 6 months, which was moderate intensity. He did not have any dyspnea, palpitations or syncope. His electrocardiography was normal.
Since there were two coronary anomalies and TMT was inconclusive, we decided to proceed with an invasive physiological assessment. EBU and AL 0.75 guiding catheter ere used to engage left and right coronary arteries respectively
Since compression in AORCA is similar to compression in myocardial bridging, we hypothesized that diastolic measures will be affected more with systolic overshoot in AORCA too. Hence, we decided to use a COMET pressure wire since it gives a measure of both DFR and FFR. Initially we did IVUS to look at the ostium of RCA, which was elliptical, which compression during systole. The baseline pd/pa in RCA was normal (0.91). But dFR was positive, just crossing the cut-off for significant narrowing. Then we started dobutamine infusion at 5 mcg/kg/min and increased by 5 mcg/kg/min till we achieved either positive FFR or heart rate reached 120 bpm with a maximum dose of 40 mcg/kg/min. On the serial increase in dobutamine dose, we noted a progressive reduction in distal diastolic pressure, whereas systolic pressure remained unchanged. On reaching 15 mcg/kg/min, FFR also became positive, mainly due to a significant drop in diastolic pressure, which in turn reduced the distal mean pressure and hence FFR became positive. DFR across LAD bridging was also positive. Pullback of pressure revealed a drop of pressure only across the myocardial bridging segment. The patient was explained the nature of the disease and the potential benefit of CABG due to the intramural course of RCA and hemodynamically significant bridging of LAD. Due to a lack of severe symptoms, the patient opted for medical therapy.
He was given beta blockers titrated to heart rate along with statins/aspirin and advised to avoid nitrates. Since the patient has presented in the fifth decade,he might not be at risk of sudden death. However, CABG might help to reduce the ischemia burden. This case highlights systolic overshoot and diastolic reduction of pressure that occurs in diastole in AORCA, proving that reduced coronary perfusion pressure may be seen in AORCA, contrary to conventional belief. CT coronary angiogram should preferably be the first line of investigation in patients with stable angina unless symptoms are severe.
