title: Low systemic vascular resistance state following off-pump coronary artery bypass grafting.
abstract: OBJECTIVE
  To determine the prevalence, hemodynamic characteristics, and risk factors for low systemic vascular resistance (SVR) state following after off-pump coronary artery bypass (OPCAB).
  
  
  METHODS
  SVR data could be obtained for 116 OPCAB patients. Low SVR was defined as an indexed systemic vascular resistance (SVRi) of <1,800 dyne x s/cm(5) x m(2) at the end of operation. Hemodynamic data were recorded preoperatively, at the end of operation, just after entering ICU, and the following morning.
  
  
  RESULTS
  Low SVR state was noted in 54 of 116 patients (53%). The SVRi values in low-SVR and non-low-SVR patients were 1,406+/-253 and 2,326+/-509 dyne x s/cm(5) x m(2) at the end of operation (p<0.0001). Increased CI level, decreased MAP level, but unchanged CVP level was observed postoperatively in the low-SVR patients. The increase in CI and decrease in MAP were maximal at the end of operation. Patients with low SVR were more likely to have a higher body mass index (24.5+/-3.6 vs. 22.9+/-2.9; p=0.013) and to be male (82% vs. 62%; p=0.036) than no-low-SVR patients. In low-SVR patients, fluid balance was more positive intraoperatively (3,537+/-1,411 vs. 3,068+/-1,597; p=0.09), but more negative at 6 hours postoperatively (-136+/-978 vs. 234+/-844; p=0.034) and 12 h postoperatively (-282+/-1,321 vs. 268+/-1,238; p=0.024).
  
  
  CONCLUSIONS
  Low SVR state, a probable manifestation of systemic inflammatory response (SIRS), is common in patients who have undergone OPCAB. For these patients it is more reasonable to maintain MAP with vasopressors by restoring vascular tone, than by volume loading.
authors.affiliation: Division of Cardiovascular Surgery, Department of Surgery, Chiba University Hospital, Chiba, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Matsuura
authors.forename: Mizuho
authors.initials: M
authors.lastname: Imamaki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ishida
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shimura
authors.forename: Hisanori
authors.initials: H
authors.lastname: Fujita
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Niitsuma
authors.forename: Masaru
authors.initials: M
authors.lastname: Miyazaki
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D018709:Statistics, Nonparametric; D014655:Vascular Resistance