Page 109 - Coronary hemodynamics in acute myocardial infarction - Matthijs Bax

Coronary autoregulation and fatal events in stable CAD
hypertrophy,20–22 diabetes mellitus,23,24 and acute renal failure,25 although the latter condition was an exclusion criterion in the present study. Disturbance of coronary autoregulation may arise from a wide variety of pathophysiological mechanisms,1,3,26,27 and larger cohorts of patients with disturbed coronary autoregulation are necessary to elucidate the origin of such dysfunction in patients with stable CAD.
Previous Studies on the Prognostic Value of Coronary Flow Velocity Abnormalities
Two other studies reported on the prognostic value of intracoronary-derived
CFVR in a reference vessel for long-term clinical outcome. Pepine et al2 showed
a similar prognostic value of CFVR in a normal reference coronary artery
in women with suspected myocardial ischemia. At 5.4 years of follow-up,
a reference vessel CFVR<2.32 was associated with a major adverse cardiac
event rate (defined as the composite of death, myocardial infarction, stroke,
and hospital stay for heart failure) of 27.0% compared with 12.2% when CFVR≥2.32 (P<0.01). Overall mortality was low at 6% (11 of 189 patients), but 6 the mortality difference between low and high reference vessel CFVR values
was not reported. The authors concluded that an impaired microvascular vasodilatory response to a potent vasodilator is associated with increased risk for major adverse cardiac event, even in the absence of significant obstructive CAD. In addition, Britten et al5 evaluated the prognostic value of the coronary flow reserve index, an index analogous to CFVR, in a normal coronary artery in patients undergoing either diagnostic cardiac catheterization for symptoms of angina or single-vessel percutaneous coronary intervention. They found a low major adverse cardiac event rate (defined as the composite of death, myocardial infarction, stroke, unstable angina, and revascularization of a de novo coronary artery lesion) of 11% (13 of 120 patients) during 6.5 years of follow-up. Notably, cardiac mortality amounted to only 1.7% (2 of 120 patients) at long-term follow- up. Coronary flow reserve index in a normal coronary artery was found to be independently associated with cardiovascular events at long-term follow-up. The authors concluded that the coronary flow reserve index, as an integrative measure of the maximal vasodilator capacity of the microcirculation as well as epicardial resistance because of subclinical atherosclerosis, is an independent predictor of long-term adverse outcome.
Differences Between Study Results: Outcome Measures and Impaired CFVR
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