title: Persistent but reversible coronary microvascular dysfunction after bypass grafting.
abstract: The effect of coronary artery bypass grafting (CABG) on absolute myocardial blood flow (MBF) has not been investigated previously. MBF (ml. min(-1). g(-1)) was measured at rest and during hyperemia (0.56 mg/kg iv dipyridamole) using H(2)(15)O and positron emission tomography in eight patients with three-vessel disease before surgery and 1 and 6 mo after full revascularization. Baseline MBF was 0.87 +/- 0.12 preoperatively and 1.04 +/- 0.14 and 0.95 +/- 0.13 at 1 and 6 mo after CABG, respectively (P < 0.05, 6 mo vs. preoperatively). Hyperemic MBF was 1.36 +/- 0.28 preoperatively and increased to 1.98 +/- 0.50 and 2.45 +/- 0.64 at 1 and 6 mo after CABG, respectively (P < 0.01, 6 mo vs. preoperatively). Coronary vasodilator reserve (hyperemic/baseline MBF) increased from 1.59 +/- 0.40 preoperatively to 1.93 +/- 0.13 and 2.57 +/- 0.49 at 1 and 6 mo, respectively (P < 0.05, 6 mo vs. preoperatively). Minimal (dipyridamole) coronary resistance (mmHg. min. g(-1). ml(-1)) fell progressively from 59.37 +/- 14.56 before surgery to a nadir of 35. 76 +/- 10.12 at 6 mo after CABG (P < 0.01 vs. preoperatively). The results of the present study confirm that CABG improves coronary vasodilator reserve progressively as a result of reduction in minimal coronary resistance. These data suggest persistent microvascular dysfunction that recovers slowly after surgery.
authors.affiliation: Royal Berkshire and Battle Hospitals, Reading, United Kingdom.
authors.forename: N
authors.initials: N
authors.lastname: Spyrou
authors.forename: M A
authors.initials: MA
authors.lastname: Khan
authors.forename: S D
authors.initials: SD
authors.lastname: Rosen
authors.forename: R
authors.initials: R
authors.lastname: Foale
authors.forename: D W
authors.initials: DW
authors.lastname: Davies
authors.forename: F
authors.initials: F
authors.lastname: Sogliani
authors.forename: R D
authors.initials: RD
authors.lastname: Stanbridge
authors.forename: P G
authors.initials: PG
authors.lastname: Camici
mesh_terms: D000328:Adult; D000368:Aged; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D003326:Coronary Circulation / Q000502:physiology*; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D008297:Male; D008833:Microcirculation / Q000502:physiology; D008875:Middle Aged; D013318:Stroke Volume; D014055:Tomography, Emission-Computed; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000502:physiology; D014664:Vasodilation / Q000502:physiology