title: Microvascular dysfunction in chronic total coronary occlusions.
abstract: BACKGROUND
  Microvascular dysfunction is defined as reduced coronary flow reserve in the absence of an epicardial stenosis. This study determined its prevalence and relation to regional myocardial function in chronic total coronary occlusions (TCO).
  
  
  RESULTS
  After recanalization and stenting of a TCO (duration, >4 weeks) in 42 patients, coronary flow velocity reserve (CFVR) was measured by intracoronary Doppler. In a subset of 27 patients, intracoronary pressure was recorded to obtain the fractional flow reserve (FFR). In 21 patients, the CFVR was reassessed after 24 hours. CFVR was <2.0 in 55% of all patients. In the subgroup with simultaneous pressure recordings, 52% of patients showed a CFVR<2.0 and a FFR>/=0.75, indicating microvascular dysfunction. Both reduced CFVR and reduced FFR occurred in only 2 patients (7.7%). CFVR and FFR were not correlated (r=0.03). A low CFVR was associated with a higher baseline average peak velocity (35.6+/-16.6 versus 22.4+/-11.5 cm/s; P=0.006). Doppler parameters did not change within 24 hours. Regional dysfunction had no influence on CFVR. Patients with diabetes and/or hypertension had a lower CFVR than those without this comorbidity (1.86+/-0.69 versus 2.36+/-0.45; P<0.05).
  
  
  CONCLUSIONS
  Microvascular dysfunction was observed in 55% of TCOs, independent of the impairment of regional myocardial function. Dysfunction was observed more often in patients with diabetes and hypertension. Neither CFVR or FFR alone is appropriate for assessing angioplasty results in patients with a TCO; CFVR should be combined with FFR to differentiate microvascular dysfunction from residual coronary stenosis or diffuse disease.
authors.affiliation: Clinic for Internal Medicine III, Friedrich-Schiller-University Jena, Erlanger Allee 101, Jena, Germany. gerald.werner@med.uni-jena.de
authors.forename: G S
authors.initials: GS
authors.lastname: Werner
authors.forename: M
authors.initials: M
authors.lastname: Ferrari
authors.forename: B M
authors.initials: BM
authors.lastname: Richartz
authors.forename: O
authors.initials: O
authors.lastname: Gastmann
authors.forename: H R
authors.initials: HR
authors.lastname: Figulla
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D002908:Chronic Disease; D003326:Coronary Circulation; D003327:Coronary Disease / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D003331:Coronary Vessels / Q000473:pathology / Q000503:physiopathology*; D048909:Diabetes Complications; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D006973:Hypertension / Q000150:complications; D017078:Laser-Doppler Flowmetry; D008875:Middle Aged