Disturbance in Venous Outflow from the Cerebral Circulation Intensifies the Release of Blood-Brain Barrier Injury Biomarkers in Patients undergoing Cardiac Surgery

OBJECTIVE:

Disturbances in venous outflow from the cerebral
circulation may result in brain injury. Severe increases in brain venous
pressure lead to brain ischemia and, subsequently, brain edema and
intracranial hemorrhages. The purpose of this study was to determine the
effect of changes in jugular venous bulb pressure (JVBP) on plasma
blood brain-barrier biomarkers concentration and disturbances in
arteriovenous total and ionized magnesium (a-vtMg and a-viMg) in brain
circulation in patients undergoing coronary artery bypass grafting surgery (CABG) with cardiopulmonary bypass (CPB).

DESIGN:

Prospective observational study.

SETTING:

Department of Cardiac Surgery at a Medical University Hospital.

PARTICIPANTS:

Ninety-two adult patients undergoing elective CABG with CPB under general anaesthesia were studied.

METHODS:

Central
venous pressure (CVP) was measured using a pulmonary artery catheter.
The right jugular vein was cannulized retrogradely for jugular venous
bulb pressure (JVBP) measurement. Concentrations of plasma S100β
protein, matrix metalloproteinase 9 (MMP-9), creatine kinase isoenzyme
BB (CK-BB) a-vtMg and a-viMg were measured as the markers of blood-brain
barrier dysfunction. All of them were analyzed in comparison with JVBP
during surgery and the early postoperative period.

RESULTS:

Elevated
JVBP was noted after CPB and after surgery. Its increase above 12 mmHg
intensified release of S100β, MMP-9 and CK-BB as well as disorders in
a-vtMg and a-viMg. CVP correlated with JVBP, S100β, and MMP-9. Moreover,
JVBP correlated with S100β and MMP-9.

CONCLUSIONS:

Cardiac
surgery increased JVBP, and JVBP elevated above 12 mmHg intensified an
increase in biomarkers of plasma blood-brain barrier disruption.