Page 91 - Coronary hemodynamics in acute myocardial infarction - Matthijs Bax

Coronary microvascular function and long-term mortality
maximally vasodilated state, the amount of adenosine used in this study is considered sufficient.46
The study protocol excluded patients with signs of acute left-sided heart failure. We felt that patients in such critical condition were not suited to undergo the extensive measurement protocol. Moreover, exclusion of these patients was motivated by the anticipated effect of a high LVEDP in the acute phase of heart failure on coronary flow velocity parameters. However, concomitantly, large MIs have been excluded from evaluation in this study; as a consequence, our observations are only valid in the context of acute anterior wall MI not complicated by acute left-sided heart failure.
In the absence of an established cut-off value, the optimal cut-off values of 5 target vessel and reference vessel CFVR for long-term cardiac mortality were
derived from the present data set. The evaluation of the relationship between
CFVR at these cut-off values and long-term clinical outcome within the same
data set may provide an advantageous estimate of the relationship, and should be confirmed in further studies.
Additionally, the study population was small, in particular at 6-month follow- up, and some predictors of long-term outcome may have been missed because of a lack of statistical power. Consequently, although our results are indicative for a strong prognostic value of CFVR in a reference vessel for long-term cardiac mortality, these results should be considered hypothesis generating, and should be confirmed in further studies. Moreover, in addition to the possible obscuring effect of the acute event on the association of target vessel CFVR with long-term outcome, the small sample size may in in part explain the lack of a statistically significant association between target vessel CFVR and long- term cardiac mortality.
Conclusions
We conclude that microvascular function, as assessed by the coronary vasodilator reserve in a reference vessel, plays a pivotal role in long-term cardiac mortality after primary PCI for STEMI.
89