Distal Coronary Pressure Hemodynamics during IABP

Distal Coronary Pressure Hemodynamics during IABP Support in a Patient with Cariogenic Shock

Case: 70’s, male.

Course: A 70’s male had suffered from chest pain and dyspnea at midnight, and then he was hospitalized to emergency department this morning. TTE showed hypokinesis in antero-septal and infero-posterior wall, and his LVEF was 30%.

ECG showed T inversion in V1-6 and chest X-P showed massive congestion and enlargement of cardiac silhouette (figure 1).

Emergency CAG revealed severe stenosis in both LCA and RCA (figure 2).

He presented cardiogenic shock due to NSTEMI with multivessel disease, thus we decided to perform complete revascularization supported by IABP and mechanical ventilation. After the stenting to LAD (figure 3), we assessed functional severity of the stenosis in RCA. FFR was measured by pressure guidewire and maximum hyperemia was induced by intra-coronary papaverine injection (figure 4). FFR value in the state that stopped IABP was 0.84. We measured FFR again in the state that supported by IABP 2:1, the value was 0.77. We measured LVEDP for the consideration of the changes in FFR value, LVEDP decreased rapidly from 35 to 26 mmHg by IABP support (figure 5).

Effects of IABP on coronary circulation are 1) diastolic augmentation of aortic driving pressure and 2) decrease in LVEDP, and then both might relate with an increase in coronary blood flow. Increase in coronary blood flow induces an increase in pressure gradient across the epicardial stenosis, which causes a decrease in FFR value (figure 6).

We had learned the following things from this case;

1. IABP was effective to reduce LVEDP and increase in coronary blood flow.
2. Decrease in FFR value indicated increase in coronary blood flow.
3. FFR measured under shock vital might be underestimated.