Page 184 - Coronary hemodynamics in acute myocardial infarction - Matthijs Bax

Chapter 11
found that an abnormal remote CFR value was associated with a 4.09 increase in 10-year cardiac mortality hazard. This predictive value of measurements in the non-IRA during PPCI had not been previously described. The impaired CFR in the non-IRA was due to an increased hyperemic microvascular resistance (and thus decreased hyperemic blood flow rate) in combination with a slightly decreased baseline microvascular resistance.
Permanently disturbed CFR values in the non-IRA 6 months post-myocardial infarction, based on low baseline microvascular resistance (and therefore high baseline flow rate), associated with a 10.7-fold increase in the risk of cardiac mortality. The size of myocardial infarction as measured by the wall motion score index obtained at 6 months of follow-up was not related to an increase in long-term cardiac mortality risk.
Notable, low CFR, the presence of systolic flow reversal, or short diastolic deceleration time in the IRA did not identify patients at high risk for long-term cardiac death. CFR in the IRA was associated with an increased risk of early cardiac mortality but not long-term mortality.
Chapter 6 is the only chapter in this thesis that investigates cardiac microcirculation in patients outside the setting of an AMI. It demonstrates the relevance of knowledge of microcirculatory function in obstructive coronary artery disease for risk stratification. In these patients, CFR assessments were performed with a Doppler FloWire in reference coronary arteries without significant stenosis. In 77 out of 178 patients, the CFR value was abnormally low (below 2.7) in the reference arteries, mainly due to a higher baseline blood flow velocity (lower baseline microvascular resistance), while no significant impaired hyperemic flow velocity or resistance was measured, indicating autoregulatory disturbances throughout the heart. After multivariate adjustment, these patients had a significantly increased hazard ratio of 3.3 for cardiac death. This underlines the fact that microvascular disease in stable coronary artery disease is an important factor for risk stratification and, hence, treatment strategies. In conjunction with the results in chapter 5, this CFR yields prognostic information in both stable and unstable coronary syndromes.
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