TOP TEN SELECTED PAPERS - June 2008

1

Scand Cardiovasc J. 2008 Jun 18:1-8. [Epub ahead of print]

The anti-inflammatory effect of bradykinin preconditioning in coronary artery
bypass grafting (bradykinin and preconditioning).

Wang X, Wei M, Kuukasjarvi P, Laurikka J, Rinne T, Moilanen E, Tarkka M.

Division of Cardiothoracic Surgery, Tampere University Hospital, Tampere,
Finland.

Objective. The present study was designed to investigate the cardioprotective
effect of exogenous administration of bradykinin (BK) in cardiac surgery.
Methods. Forty-one patients who were scheduled for isolated coronary artery
bypass grafting (CABG) were randomized into Control group and BK group. BK
patients received 25 microg bradykinin infusion for 7 minutes before the
cardiopulmonary bypass (CPB). Release of cardiac specific troponin I (TnI) and
creatine kinase cardiac isoenzyme (CK-MB) was recorded. Perioperative circulating
cytokine interleukin (IL)-6, 8 and 10 were measured. Results. There was no
significant difference in TnI between groups. However, BK patients released
significantly less CK-MB than the controls (p=0.043). Systemic plasma levels of
IL-6, IL-8 and IL-10 increased significantly after reperfusion in both groups as 
compared with baseline (p < 0.05). The ratio of IL-8 to IL-10 was significantly
lower in BK groups than in controls (p=0.03). Conclusions. We conclude that
exogenous administration of BK prior to CPB in CABG patients attenuates ischemic 
myocardial injury. It also shifts the circulating inflammatory cytokine balance
towards the anti-inflammatory direction.

J Biomed Opt. 2008 May-Jun;13(3):033001.

Brain oxymetry in the operating room: current status and future directions with
particular regard to cytochrome oxidase.

Kakihana Y, Matsunaga A, Yasuda T, Imabayashi T, Kanmura Y, Tamura M.

Kagoshima University Hospital, Division of Intensive Care Medicine, 8-35-1
Sakuragaoka, Kagoshima 890-8520, Japan.

Near-infrared spectroscopy (NIRS) is a cerebral monitoring method that
noninvasively and continuously measures cerebral hemoglobin oxygenation and the
redox state of cytochrome oxidase using highly tissue-permeable near-infrared
light. This technique now has wide clinical application, and its usefulness in
the measurement of cerebral hemoglobin oxygenation has been confirmed under
global cerebral injury and/or hypoxemic hypoxia; however, regional cerebral
infarction located far from the monitoring site may not be detected by NIRS.
Furthermore, the specificity and accuracy of the measurement of the redox state
of cytochrome oxidase remain controversial. We apply NIRS to both animal and
clinical investigations. Based on these results, we discuss the significance of
the measurement of cerebral hemoglobin oxygenation and cytochrome oxidase in vivo
and in clinical medicine. Using our algorithm, cytochrome oxidase signals are
unaffected by hemoglobin signals, even when hematocrit values change from 35 to
5% under cardiopulmonary bypass in a dog model. In the clinical study, cytochrome
oxidase during surgery is likely to be a good (though not perfect) predictor of
postoperative cerebral outcome. NIRS appears to be a promising technology, but
additional investigations are required to establish its clinical efficacy and
justify its routine use during operative and perioperative periods.

Eur J Cardiothorac Surg. 2008 Jun 23. [Epub ahead of print]

Ascending aortic cannulation in acute aortic dissection type A: the Hannover
experience.

Khaladj N, Shrestha M, Peterss S, Strueber M, Karck M, Pichlmaier M, Haverich A, 
Hagl C.

Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover
Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.

Objective: The incidence of embolic events and of cerebral malperfusion in aortic
dissection type A (AADA) must be viewed in the context of the existence of a
number of possible cannulation techniques. Since femoral cannulation is thought
to be associated with a higher risk of perfusion of the false lumen and
retrograde embolization, techniques establishing antegrade flow may provide a
better option. We describe herein our experience with ascending aortic
cannulation in this special patient population. Methods: Between November 1999
and February 2006, 122 patients underwent operation for AADA with arterial access
via the dissected ascending aorta. The aorta was cannulated at the site of the
minimal distances of the dissected layers. Double purse-string sutures were used 
to support the cannula. Pressure monitoring in both radial arteries as well as
bilateral cerebral oxygen saturation measurement helped to identify malperfusion 
after establishment of cardiopulmonary bypass. Aortic arch as well as aortic root
surgery was performed, as dictated by the pathology. Selective antegrade cerebral
perfusion and moderate hypothermia were used for brain and body protection.
Results: Malperfusion occurred in three patients (2.5%). Hospital mortality was
15% for the entire cohort (18 patients). Permanent neurological dysfunction was
detected in 15 patients (12%), whereas temporary neurological dysfunction
occurred in 21 (17%). Total arch replacement was performed in 31 patients (25%). 
Conclusion: Direct cannulation of the ascending aorta is an easy and safe method 
in patients with AADA. This technique, which also avoids retrograde flow in the
downstream aorta, is an alternative to time-consuming axillary artery access.

Eur J Cardiothorac Surg. 2008 Jun 23. [Epub ahead of print]

Using reagent-supported thromboelastometry (ROTEM((R))) to monitor haemostatic
changes in congenital heart surgery employing deep hypothermic circulatory
arrest.

Straub A, Schiebold D, Wendel HP, Hamilton C, Wagner T, Schmid E, Dietz K, Ziemer
G.

Department of Thoracic, Cardiac and Vascular Surgery, University of Tübingen,
Germany.

Objective: Cardiac surgery employing cardiopulmonary bypass (CPB) and deep
hypothermic circulatory arrest (DHCA) can induce coagulation disturbances and
bleeding complications that may be especially severe in infants. A better
understanding of the coagulopathy and a quick method for its evaluation would be 
helpful in the management of patients exposed to CPB and DHCA. This study aimed
to monitor coagulation defects in congenital heart surgery using rotational
thromboelastometry (ROTEM((R))), standard coagulation tests and platelet flow
cytometry. Methods: The study comprised 10 infants undergoing surgery for
congenital heart disease on CPB and DHCA. Blood was sampled at skin incision,
after heparinisation during CPB (directly pre- and directly post-DHCA) and after 
protamine administration post-CPB. ROTEM((R)) using different reagents including 
a heparinase-containing assay to evaluate coagulation during heparinisation, APTT
and INR, and flow cytometry to evaluate platelet activation were performed.
Results: During CPB, the ROTEM((R)) indicated CPB-induced clotting factor
depletion and platelet dysfunction that persisted after CPB and heparin
neutralisation. ROTEM((R)) results were available within 15min and therefore much
faster than standard tests. ROTEM((R))-guided specific blood product treatment
resulted in satisfactory coagulatory function. The highest degree of platelet
activation was found directly after DHCA. Conclusions: A major benefit of
ROTEM((R)) is the quick detection of a developing coagulopathy already during
CPB. ROTEM((R)) guides quick and specific blood product treatment after CPB,
which may decrease bleeding complications in cardiac surgery. The finding of
maximal platelet activation directly after DHCA suggests that not only CPB but
also hypothermia activates platelets in vivo, thereby contributing to platelet
dysfunction.

Ann Thorac Cardiovasc Surg. 2008 Jun;14(3):138-48.

The methodologies of hypothermic circulatory arrest and of antegrade and
retrograde cerebral perfusion for aortic arch surgery.

Apostolakis E, Akinosoglou K.

Cardiothoracic Surgery-Clinic, University Hospital of Patras, Rio, Greece.

In spite of recent advances in thoracic aortic surgery, postoperative
neurological injury still remains the main cause of mortality and morbidity after
aortic arch operation. The use of cardiopulmonary bypass (CPB) and hypothermic
circulatory arrest, temporary interruption of brain circulation, transient
cerebral hypoperfusion, and manipulations on the frequently atheromatic aorta all
produce neurological damages. The basic established techniques and perfusion
strategies during aortic arch replacement number three: hypothermic circulatory
arrest (HCA), antegrade cerebral perfusion (ACP), and retrograde cerebral
perfusion (RCP). During the past decade and after several experimental studies,
RCP lost its previous place in the armamentarium of brain protection, giving it
up to ACP as a major method of brain perfusion during HCA. HCA should be applied 
at a temperature of asymptotically equal to 20 degrees C with long-lasting
cooling and rewarming and should not exceed by itself the time of 20-25 min. RCP 
does not seem to prolong safe brain-ischemia time beyond 30 min, but it appears
to enhance cerebral hypothermia by its massive concentration inside the brain
vein sinuses. HCA combined with ACP, however, could prolong safe brain-ischemia
time up to 80 min. Cold ACP at 10 degrees -13 degrees C should be initially
applied through the right subclavian or axillary artery and continued
bihemispherically through the left common carotid artery at first and later the
anastomosed graft, with a mean perfusion pressure of 40-70 mm Hg. The safety of
temporary perfusion is being confirmed by the meticulous monitoring of brain
perfusion through internal jugular bulb O(2) saturation, electroencephalogram,
and transcranial comparative Doppler velocity of the middle cerebral arteries.

Intensive Care Med. 2008 Jun 25. [Epub ahead of print]

Antithrombin level and circuit thrombosis during hemofiltration after
cardiopulmonary bypass.

Lanquetot H, Leprince T, Ragot S, Boinot C, Jayle C, Robert R, Macchi L.

Département d’anesthésie réanimation, CHU Poitiers, Poitiers cedex, France.

OBJECTIVE: Hemofilter thrombosis occurs frequently during continuous veno-venous 
hemofiltration in intensive care units. Among coagulation disorders, antithrombin
deficiency has been shown to be linked to hemofilter thrombosis. We investigated 
whether there was an association between antithrombin level activity and
hemofilter thrombosis occurrence during early continuous hemofiltration following
cardiopulmonary bypass. DESIGN: Prospective observational study. SETTING:
Intensive care unit in University Teaching Hospital. PATIENTS AND PARTICIPANTS:
Forty-eight consecutive patients. MEASUREMENTS AND RESULTS: Antithrombin level
activity was measured just before the start of hemofiltration, and repeated at 24
h intervals for a total of 3 days. Hemofilter thrombosis episodes were recorded
at each 24-h interval following antithrombin level activity measurement. Subjects
were classified as HT when one or more episodes of hemofilter thrombosis appeared
in this period and NHT if none. Morbidity parameters and mortality were recorded.
Mean initial antithrombin level activity was low and not different in HT and NHT 
groups at day 0 (60.6 +/- 20.9% vs. 63.4 +/- 19.9%, P = 0.68). Antithrombin level
activity was lower at day 1 (47.2 +/- 12.0% vs. 58.2 +/- 15.2%, P = 0.03) and day
2 (41.2 +/- 15.3% vs. 53.5 +/- 14.1%, P = 0.04) in HT group. However,
antithrombin level activity was not shown to be predictive of HT in multivariate 
analysis. Morbidity and mortality did not differ significantly between the two
groups. CONCLUSION: Only a weak association was found between antithrombin level 
activity and HT during early veno-venous hemofiltration post-cardiopulmonary
bypass. This result was not confirmed in multivariate analysis. DESCRIPTOR: Renal
failure: dialysis and hemofiltration.

Ann Cardiol Angeiol (Paris). 2008 Jun 4. [Epub ahead of print]

[Oxidative stress is exacerbated in diabetic patients during cardiopulmonary
bypass.]

[Article in French]

Marty JC, Bendhadra S, Amoureux S, Guilland JC, Vergely C, Rochette L, Girard C.

Service d’anesthésie-réanimation, CHU Bocage, Dijon, France.

Circulation on blood extracorporeally through plastic tubing activates several
pathways including systemic inflammation and oxidative stress. These phenomena
are suspected to participate to neurological and cardiovascular side effects
observed in the patients under cardiopulmonary bypass (CPB). A direct
relationship, in diabetic patients, between hyperglycemia and morbidity and
mortality has been established. However, it is still unclear whether
perioperative hyperglycemia has a direct effect on adverse events in cardiac
surgery. The purpose of this study was to determine the influence of
hyperglycemia on inflammation and oxidative stress in patients under CPB during
cardiac surgery. MATERIAL AND METHODS: Control patients (n=17) and diabetic (type
2) patients (n=13) were included in this study. Blood samples were drawn before, 
during and after the CPB. Oxidative stress was evaluated in the plasma by direct 
and indirect approaches. Direct detection of ascorbyl radicals was assessed by
electron spin resonance spectroscopy. An index: ascorbyl radical/vitamin C ratio 
is an indicator of the degree of oxidative stress taking place in the plasma.
Oxygen radical absorbing capacity (ORAC) values were used as measurement of
antioxidant capacity of the plasma. To determine inflammation profile of
patients, we measure the evolution of plasma concentration of interleukin 8
(IL-8). RESULTS: During cross clamping and post-CPB, the index ascorbyl
radical/vitamin C is increased; the value of the index is more significant in
diabetic patients. Concomitantly, ORAC values decreased in all the patients
during cross clamping (p<0.05). Results concerning inflammatory index showed that
IL-8 levels increased during the CPB. CONCLUSION: In conclusion, the current
study indicates that a systemic oxidative stress occurs during CPB and post-CPB
periods and that in patients with type 2 diabetes mellitus, the systemic
oxidative stress was increased.

Paediatr Anaesth. 2008 Jun 9. [Epub ahead of print]

Intraoperative extracorporeal membrane oxygenation and survival of pediatric
patients undergoing repair of congenital heart disease.

Flick RP, Sprung J, Gleich SJ, Barnes RD, Warner DO, Dearani JA, Scott PD, Hanson
AC, Schroeder DR, Schears GJ.

Department of Anesthesiology, College of Medicine, Rochester, MN, USA.

Background: We studied the association between the introduction of extracorporeal
membrane oxygenation (ECMO) into routine practice and the survival of children
who failed weaning from cardiopulmonary bypass (CPB). We compare two periods,
before formal introduction of ECMO in our institution (1993-1999, pre-ECMO era)
and after ECMO became a formalized program (2000-2006, ECMO era). Methods:
Retrospective review of Mayo Clinic Database between 1993 and 2006 for outcomes
of patients <18 years old who required ECMO during repair of congenital heart
malformations. Results: Thirty-five children during ECMO era received
intraoperative ECMO, and 17 (54%) survived to hospital discharge. The frequency
of ECMO use was the highest in neonates, therefore, this was the only subcohort
of pediatric patients that allowed comparison of survival between the pre-ECMO
and ECMO eras. When compared to pre-ECMO era, neonatal survival increased during 
ECMO era (P = 0.043). ECMO was mostly used in neonates with higher complexity of 
cardiac defects undergoing more complex repairs, and the overall improvement of
survival was primarily due to better survival of these patients. During pre-ECMO 
era, survival was lower in patients with higher risk (P = 0.001). However, during
ECMO era, no difference in survival was observed across assigned risk groups (P =
0.658). Conclusions: The availability of ECMO for neonates failing to wean from
CPB was associated with improved survival, especially in children undergoing
repair of the most complex congenital heart malformations. After introduction of 
ECMO, survival improved and no longer depended upon the complexity of surgical
repair.

J Cardiothorac Vasc Anesth. 2008 Jun;22(3):418-22. Epub 2008 Jan 22.

Can femoral artery pressure monitoring be used routinely in cardiac surgery?

Haddad F, Zeeni C, El Rassi I, Yazigi A, Madi-Jebara S, Hayeck G, Jebara V,
Yazbeck P.

Department of Anesthesiology and Intensive Care, Hotel Dieu de France Hospital,
Beirut, Lebanon. fflhlb@yahoo.com

OBJECTIVE: The purpose of this study was to evaluate the safety of femoral
arterial pressure monitoring in cardiac surgery. DESIGN: Prospective,
observational study. SETTING: Cardiac surgery unit (CSU) in a university
hospital. PARTICIPANTS: Of a total of 2,350 consecutive patients scheduled for
elective cardiac surgery with cardiopulmonary bypass, 2,264 patients with femoral
artery pressure monitoring were included. INTERVENTIONS: A femoral arterial
catheter was inserted percutaneously before the induction of anesthesia. The
catheter was withdrawn 40 to 96 hours after surgery. It was replaced by a radial 
artery catheter in patients staying for more than 4 days in the CSU or in case of
pulse loss or lower limb ischemia. The catheter was removed and sent for cultures
whenever it showed local changes, discharge, or if sepsis was suspected.
MEASUREMENTS AND MAIN RESULTS: Pain on insertion ranged from 0 to 20 mm on the
100-mm visual analog scale. Complications related to femoral artery cannulation
were recorded. No cases of femoral artery thrombosis, lower extremity ischemia,
or hematoma requiring surgery were noted. Small hematomas were observed in 3.3%
of patients. The incidence of oozing was 2.1% after the insertion of the catheter
and 4.9% after its removal. Three cases (0.13%) of serious bleeding occurred; 2
required surgery. Eight percent of catheter tips were sent for culture, and
positive bacterial growth was recorded in 18.6% of them. Catheter-related blood
stream infection occurred in 0.5% of the total patient population included.
CONCLUSIONS: Femoral artery pressure monitoring was associated with a low
complication rate and, therefore, it can be used routinely in cardiac surgery.

ASAIO J. 2008 May-Jun;54(3):306-15.

A performance evaluation of eight geometrically different 10 Fr pediatric
arterial cannulae under pulsatile and nonpulsatile perfusion conditions in an
infant cardiopulmonary bypass model.

Rider AR, Ji B, Kunselman AR, Weiss WJ, Myers JL, Undar A.

Department of Pediatrics, Penn State Milton S. Hershey Medical Center, Penn State
College Medicine, Penn State Children's Hospital, Hershey, Pennsylvania
17033-0850, USA.

This investigation compared pressure drops and surplus hemodynamic energy (SHE)
levels in eight commercially available pediatric aortic cannulae (10 Fr) with
different geometries during pulsatile and nonpulsatile perfusion conditions in an
in vitro infant model of cardiopulmonary bypass. For each trial, the cannula was 
placed at the distal end of the arterial line, and the insertion tip was fixed to
the inlet of the simulated patient. The pseudo patient was subjected to seven
pump flow rates ranging from 400 to 1000 ml/min (at 100 ml/min increments), and
the mean arterial pressure was set at a constant 40 mm Hg via Hoffman clamp. Of
the eight cannulae, the Surgimedics and THI models had significantly larger
pressure drops (48.8 +/- 0.3 mm Hg and 48.3 +/- 1.4 mm Hg, respectively; 600
ml/min pulsatile) compared with the RMI cannula (27.6 +/- 1.2 mm Hg; 600 ml/min
pulsatile), which created, on average, half of the pressure drop seen in the
poorest performing cannulae. When perfusion mode was switched from nonpulsatile
to pulsatile, there was a 7-9 fold increase in delivery of SHE recorded at both
the pre- and postcannulae sites, regardless of which cannula was being tested.
Despite being classified under the same size (10 Fr), these eight cannulae were
found to vary considerably in length, inner diameter, and geometrical design. The
results suggest that these differences can have a significant impact on pressure 
drops, as well as generation and delivery of SHE. Furthermore, it was found that 
pulsatile perfusion produced more "extra" hemodynamic energy when compared with
nonpulsatile perfusion, regardless of cannula model.