Coronary microvascular dysfunction after elective percutaneous coronary intervention: correlation with exercise stress test results.

Objectives: We assessed whether exercise stress test (EST) results are related to the presence of coronary microvascular dysfunction (CMVD) in patients undergoing elective percutaneous coronary intervention (PCI).
Background: Previous studies showed that EST is poorly reliable in predicting restenosis after PCI; some studies also showed CMVD in the territory of the treated vessel.
Methods: We studied 29 patients (age 64 ± 6, 23 M) with stable coronary artery disease and isolated stenosis (>75%) of the left anterior descending (LAD) coronary artery, undergoing successful PCI with stent implantation. EST and assessment of coronary microvascular function were performed 24h, 3 months and 6 months after PCI. Coronary blood flow (CBF) response to adenosine and to cold-pressor test (CPT) was assessed in the LAD coronary artery by transthoracic Doppler echocardiography.
Results: Patients with ST-segment depression ≥ 1 mm at EST performed 24h after PCI (n=11, 38%) showed a lower CBF response to adenosine compared to those with negative EST (1.65 ± 0.4 vs. 2.11 ± 0.4, respectively, p=0.003), whereas the difference in CBF response to CPT was not significant (1.44 ± 0.4 vs. 1.64 ± 0.3, respectively; p=0.11). At 3-month and 6-month follow-up a positive EST was found in 12 (41%) and 13 (44%) patients, respectively; patients with positive EST also had lower CBF response to adenosine compared to those with negative EST (3 months: 1.69 ± 0.3 vs. 2.20 ± 0.3, respectively; 6 months: 1.66 ± 0.2 vs. 2.32 ± 0.3, respectively; p<0.001 for both).
Conclusions: Positive EST after elective successful PCI consistently reflects impairment of hyperemic CBF due to CMVD, which persists over a follow-up period of 6 months.
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