Simultaneous Doppler and pressure recordings to assess microvascular dysfunction in chronic total coronary...

Microvascular dysfunction (MD) is frequently observed in chronic total coronary occlusions (TCOs). This impairs the use of Doppler velocimetry for the guidance of PTCA. It is yet unknown to what extent microvascular dysfunction may recover during follow-up, and whether this may influence long-term outcome.

After recanalization and stenting of TCOs (duration > 4 weeks) in 56 patients, coronary flow velocity reserve (CFVR) and fractional flow reserve (FFR) were recorded. MD was defined as a CFVR < 2.0 in the absence of a significant epicardial lesion (FFR > or = 0.75). Patients were followed for 5.3 +/- 1.5 months with reassessment of CFVR, FFR, and of LV function during a repeat angiography.

MD was observed in 50% after PTCA. The CFVR improved during follow-up from 1.93 +/- 0.62 to 2.35 +/- 0.69 (p < 0.001), with a decrease of baseline APV (31.0 +/- 13.6 cm/s to 25.7 +/- 15.0 cm/s; p = 0.022). At follow-up MD was observed less frequently (20%). In 20 of 36 patients with initially impaired LV function, the ejection fraction (LVEF) improved. The CFVR at baseline did not predict LV recovery. Target vessel failure (restenosis > 50% diameter stenosis) occurred in 43%. CFVR did not predict TVF, but FFR tended to be lower in patients with TVF. In 8 patients with FFR > or = 0.93 after recanalization, no TVF was required.

MD improved in more than 50% with initially impaired MD after PTCA during a long-term follow-up. CFVR at baseline was not closely related to LV recovery. The high rate of TVF was not predictable by CFVR. The FFR may be more valuable for optimizing PTCA in TCOs than Doppler parameters.