TOP TEN SELECTED PAPERS - August 2009

1

Eur J Cardiothorac Surg. 2009 Aug 27. [Epub ahead of print]

Hypothermic extracorporeal circulation in immature swine: a comparison of
continuous cardiopulmonary bypass, selective antegrade cerebral perfusion and
circulatory arrest.

Sasaki H, Guleserian KJ, Rose R, Fotiadis C, Boyer PJ, Forbess JM.

Department of Cardiothoracic Surgery, Children's Medical Center Dallas, The
University of Texas Southwestern Medical Center, Dallas, TX, USA.

Objective: Selective antegrade cerebral perfusion (SCP) has been widely used
during complex congenital heart surgery and theoretically affords some degree of 
neuroprotection. There are limited data to support this claim, however. This
study was designed to compare, at profound hypothermia, continuous
cardiopulmonary bypass, SCP and circulatory arrest in a survival model of
extracorporeal circulation in immature swine. Methods: Fifteen piglets
(5.9+/-1.1kg) were placed on cardiopulmonary bypass (CPB), cooled to a rectal
temperature of 15 degrees C and subjected to 90min of hypothermic circulatory
arrest (HCA), selective cerebral perfusion (30mlkg(-1)min(-1)) (SCP) or systemic 
full-flow perfusion (FF; 100mlkg(-1)min(-1)). Piglets were weaned from CPB and
extubated. Daily neurologic assessments were performed for 5 days using
neurologic deficit scoring (NDS) and overall performance categories (OPC). On
postoperative day (POD) 5, all brains were perfusion-fixed and assigned a total
histologic score (THS) of neuronal injury by a neuropathologist blinded to the
study groups. Results: The median POD 1 NDS/OPC was 0 (range 0-115)/1(range 1-2) 
for FF, 130 (range 0-195)/2 (range 1-3) for HCA and 0 (range 0-30)/1 for SCP.
Although there was a trend for the neurologic status in the HCA group to be worse
on POD 1, this did not achieve significance, and both NDS and OPC scores for HCA 
animals normalised by POD 5. Median THS was 9 (range, 0-11) for FF, 12 (range,
4-14) for HCA and 9 (range, 0-11) for SCP with no statistically significant
difference between the groups. Conclusions: In this survival model of hypothermic
extracorporeal circulatory support in immature swine, histologic brain injury was
similar in piglets subjected to FF, SCP or HCA. Although the HCA group tended to 
have worse early neurologic outcome, any difference clearly disappeared by POD 5.
These data raise the possibility that profound hypothermia alone during
extracorporeal support may produce this observed brain injury. Additional study
is required to define the precise aetiology of the brain injury observed in this 
animal model.

Asian Cardiovasc Thorac Ann. 2009 Aug;17(4):401-7.

Hypothermic circulatory arrest: renal protection by atrial natriuretic peptide.

Ohno M, Omoto T, Fukuzumi M, Oi M, Ishikawa N, Tedoriya T.

Department of Cardiovascular and Thoracic Surgery, Showa University, Tokyo,
Japan. m.ohno21@med.showa-u.ac.jp

Moderate hypothermic circulatory arrest with selective cerebral perfusion has
been developed for cerebral protection during thoracic aortic surgery. However,
visceral organs, particularly the kidneys, suffer greater tissue damage under
moderate hypothermic circulatory arrest, and acute renal failure after
hypothermic circulatory arrest is an independent risk factor for early and late
mortality. This study investigated whether atrial natriuretic peptide could
prevent the reduction in renal perfusion and protect renal function after
moderate hypothermic circulatory arrest. Twelve pigs cooled to 30 degrees C
during cardiopulmonary bypass were randomly assigned to a peptide-treated group
of 6 and a control group of 6. Moderate hypothermic circulatory arrest was
induced for 60 min. Systemic arterial mean pressure and renal artery flow did not
differ between groups during the study. However, renal medullary blood flow
increased significantly in the peptide-treated group after hypothermic
circulatory arrest. Myeloperoxidase activity was significantly reduced in the
medulla of the peptide-treated group. Renal medullary ischemia after hypothermic 
circulatory arrest was ameliorated by atrial natriuretic peptide which increased 
medullary blood flow and reduced sodium reabsorption in the medulla. Atrial
natriuretic peptide also reduced the release of an inflammatory marker after
ischemia in renal tissue.

J Thorac Cardiovasc Surg. 2009 Aug 24. [Epub ahead of print]

Port-access minimally invasive surgery for atrial septal defects: A 10-year
single-center experience in 166 patients.

Vistarini N, Aiello M, Mattiucci G, Alloni A, Cattadori B, Tinelli C, Pellegrini 
C, D'Armini AM, Viganò M.

Cardiac Surgery Department, Fondazione IRCCS Policlinico San Matteo, Pavia,
Italy.

OBJECTIVE: We assessed the surgical results and the benefits to the patient of a 
minimally invasive surgical approach for atrial septal defects. METHODS: Between 
May 1998 and May 2008, 166 patients (median age, 44 years) had surgery for atrial
septal defects in our institution. Of these patients, 118 (71%) had a patent
foramen ovale (associated with atrial septal aneurysm in 48 cases), 33 (20%) had 
a wide ostium secundum defect, 6 (3.6%) had an ostium primum defect, 6 (3.6%) had
a sinus venosus defect with abnormal pulmonary vein connection, and 1 (0.6%) had 
a coronary sinus defect. In 2 cases (1.2%) patients were referred to our
department for surgical correction after failure of interventional occluder
placement. All patients were operated on via a right minithoracotomy (mean
incision, 5.5 +/- 1 cm) in the fourth intercostal space and under cardiopulmonary
bypass. RESULTS: The HeartPort access system was used in 106 patients (64%), with
an endoaortic clamp (central kit in 50 cases and peripheral kit in 56). In the
remaining patients (36%), we preferred the Portaclamp system (37 cases) or the
Chitwood clamp (23 cases). Average crossclamp time was 38.4 +/- 22.2 minutes with
a mean cardiopulmonary bypass time of 64.9 +/- 34.5 minutes. There was no
conversion in classic sternotomy. There were no early or late hospital deaths.
Surgical revision was performed in 6 patients for bleeding from the thoracic
wall. The mean hospital stay was 5.8 days. At 51 months mean follow-up, 4
patients died of non-cardiac-related causes. CONCLUSIONS: Port-access minimally
invasive surgery for atrial septal defects is a safe, less-invasive,
reproducible, and cosmetic operation, providing an excellent outcome and an
effective correction, and could be now considered the standard approach for this 
type of patient.

Eur J Cardiothorac Surg. 2009 Aug 18. [Epub ahead of print]

Minimised versus conventional cardiopulmonary bypass: outcome of high-risk
patients.

Haneya A, Philipp A, Schmid C, Diez C, Kobuch R, Hirt S, Zink W, Puehler T.

Department of Cardiothoracic Surgery, University Medical Center Regensburg,
Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany.

Background: Coronary artery bypass grafting (CABG) with extracorporeal
circulation (ECC) is the gold standard for surgical coronary re-vascularisation. 
Recently, minimised extracorporeal circulation system (MECC) has been postulated 
a safe and advantageous alternative for multi-vessel CABG. Method: Between
January 2004 and December 2007, 244 high-risk patients (logistic EuroScore
(ES)>10%) underwent CABG in our institution. ECC was used in 139 (57%) and MECC
in 105 (43%) patients. Demographic data including age (MECC: 73.4+/-7.4 years;
ECC: 73.3+/-6.4 years), ES (MECC: 19.2+/-9.8%; ECC: 21.4+/-11.9%),
left-ventricular ejection fraction (MECC: 45.6+/-16.1%; ECC: 43.1+/-15.3%),
diabetes mellitus (MECC: 14.3%; ECC: 15.1%) and COPD (MECC: 6.7%; ECC: 7.9%) did 
not differ between the two groups. Preoperative end-stage renal failure was an
exclusion criterion. The clinical course and serological/haematological
parameters in the ECC and MECC patients were compared in a retrospective manner. 
Results: Although the numbers of distal anastomoses did not differ between the
two groups (MECC: 3.0+/-0.9; ECC: 2.9+/-0.9), ECC time was significantly shorter 
in the MECC group (MECC: 96+/-33 min; ECC: 120+/-50min, p<0.01). Creatinine
kinase (CK) levels were significantly lower 6h after surgery in the MECC group
(MECC: 681+/-1505Ul(-1); ECC: 1086+/-1338Ul(-1), p<0.05) and the need of red
blood cell transfusion was significantly less after MECC surgery (MECC: 3 [range:
1-6]; ECC: 5 [range: 2-9] p<0.05). Moreover, 30-day mortality was significantly
lower in the MECC group as compared to the ECC group (MECC: 12.4%; ECC: 26.6,
p<0.01). Discussion: MECC is a safe alternative for CABG surgery. A lower 30-day 
mortality, lower transfusion requirements and less renal and myocardial damage
encourage the use of MECC systems, especially in high-risk patients.

Eur J Cardiothorac Surg. 2009 Aug 17. [Epub ahead of print]

Cardiopulmonary bypass with physiological flow and pressure curves: pulse is
unnecessary!

Voss B, Krane M, Jung C, Brockmann G, Braun S, Günther T, Lange R, Bauernschmitt 
R.

Klinik für Herz- und Gefässchirurgie, Deutsches Herzzentrum München, Technische
Universität München, Munich, Germany.

Objective: Advocates of pulsatile flow postulate that the flow pattern during
extracorporeal circulation (ECC) should be similar to the physiological one.
However, the waveforms generated by clinically used pulsatile pumps are by far
different from the physiological ones. Therefore, we constructed a new
computer-controlled pulsator which can provide nearly physiological perfusion
patterns during ECC. We compared its effect (group 1) with pulsatile (group 2)
and non-pulsatile (group 3) perfusion generated by a conventional roller pump.
Methods: Thirty pigs (10 per group) underwent 180min ECC with an aortic
cross-clamp time of 120min. Pulse pressure, peak aortic flow, dp/dt(max),
pulsatility index and energy-equivalent pressure were measured online. Renal and 
intestinal blood flow was calculated by fluorescent microspheres. The
inflammatory response was assessed by the level of interleukin 6/1ra, the
haemolysis by the free haemoglobin, and the escape rate of plasma protein by the 
disappearance rate of Evans Blue dye. Results: When compared to the preoperative 
curves, pulsatile waveforms during ECC were similar in group 1 and severely
damped in group 2. Inflammatory response increased without significant
differences between the groups. There were no differences between groups in renal
and bowel blood flow. Free haemoglobin after ECC was higher in the pulsatile
groups (group 1=43+/-144mgdl(-1), group 2=40+/-164mgdl(-1), group
3=11+/-4mgdl(-1); group 1 vs 2 (ns); group 1 or 2 vs 3 (p<0.001)). The escape
rate of Evans Blue increased after ECC in group 1 1.8-fold (p<0.05), in group 2
1.45-fold (p<0.05) and in group 3 1.27-fold (ns). Conclusion: Even when using
pulsatile flow patterns which mimic closely the physiological waveforms, there is
no advantage concerning organ perfusion or inflammatory response. Moreover, the
extent of haemolysis and capillary leak is higher compared to non-pulsatile
perfusion. Efforts to optimise pulsatility are not justified.

Eur J Cardiothorac Surg. 2009 Aug 13. [Epub ahead of print]

Open-heart surgery in premature and low-birth-weight infants - a single-centre
experience.

Lechner E, Wiesinger-Eidenberger G, Weissensteiner M, Hofer A, Tulzer G,
Sames-Dolzer E, Mair R.

Department of Neonatology, Children's and Maternity Hospital Linz,
Krankenhausstrasse 26-30, 4020 Linz, Austria.

Objective: Because of their poor clinical status, infants may require surgery for
congenital heart disease regardless of weight or prematurity. This retrospective 
review describes a single-centre experience with open-heart surgery in low-weight
infants. Methods: From November 1997 to December 2006, 411 open-heart surgery
procedures were performed in neonates. This included 46 consecutive infants
weighing less than 2500g, who underwent cardiopulmonary bypass for correction of 
congenital heart defects (n=34) or Norwood stage I palliation of hypoplastic left
heart syndrome (HLHS) (n=12). In the low-weight group were 23 males and 23
females with a median age of 10 days and a median weight of 2.26kg (range:
1.28-2.49kg). Results: Early mortality was 8.2% in patients weighing more than
2.5kg and 13% in the low-weight group. Within the low-weight group, weight at
surgery, history of prematurity and prevalence of additional extracardiac
malformations did not influence early mortality. At a median follow-up time of 32
months overall mortality was 21%. Thirty-four patients had a neurological
follow-up examination 30 months postoperatively. Of the 34 survivors, 11 showed
neurological deficits. Conclusions: In our patient population, early mortality
was higher for infants weighing less than 2.5kg. However, within the low-weight
group, lower weight at surgery or history of prematurity was not associated with 
a higher mortality or bad neurological outcome.

J Am Coll Cardiol. 2009 Aug 18;54(8):730-7.

Comment in:
    J Am Coll Cardiol. 2009 Aug 18;54(8):738-9.

Outcome of extracorporeal membrane oxygenation for early primary graft failure
after pediatric heart transplantation.

Tissot C, Buckvold S, Phelps CM, Ivy DD, Campbell DN, Mitchell MB, da Cruz SO,
Pietra BA, Miyamoto SD.

Children's Hospital of Denver, Aurora, CO, USA. cecile.tissot@hotmail.com

OBJECTIVES: We sought to analyze the indications and outcome of extracorporeal
membrane oxygenation (ECMO) for early primary graft failure and determine its
impact on long-term graft function and rejection risk. BACKGROUND: Early
post-operative graft failure requiring ECMO can complicate heart transplantation.
METHODS: A retrospective review of all children requiring ECMO in the early
period after transplantation from 1990 to 2007 was undertaken. RESULTS:
Twenty-eight (9%) of 310 children who underwent transplantation for
cardiomyopathy (n = 5) or congenital heart disease (n = 23) required ECMO
support. The total ischemic time was significantly longer for ECMO-rescued
recipients compared with our overall transplantation population (276 +/- 86 min
vs. 242 +/- 70 min, p < 0.01). The indication for transplantation, for ECMO
support, and the timing of cannulation had no impact on survival. Hyperacute
rejection was uncommon. Fifteen children were successfully weaned off ECMO and
discharged alive (54%). Mean duration of ECMO was 2.8 days for survivors (median 
3 days) compared with 4.8 days for nonsurvivors (median 5 days). There was 100%
3-year survival in the ECMO survivor group, with 13 patients (46%) currently
alive at a mean follow-up of 8.1 +/- 3.8 years. The graft function was preserved 
(shortening fraction 36 +/- 7%), despite an increased number of early rejection
episodes (1.7 +/- 1.6 vs. 0.7 +/- 1.3, overall transplant population, p < 0.05)
and hemodynamically comprising rejection episodes (1.3 +/- 1.9 vs. 0.7 +/- 1.3,
overall transplant population, p < 0.05). CONCLUSIONS: Overall survival was 54%, 
with all patients surviving to at least 3 years after undergoing transplantation.
None of the children requiring >4 days of ECMO support survived. Despite an
increased number of early and hemodynamically compromising rejections, the
long-term graft function is similar to our overall transplantation population.

Br J Anaesth. 2009 Jul 31. [Epub ahead of print]

Profound haemodilution during normothermic cardiopulmonary bypass influences
neither gastrointestinal permeability nor cytokine release in coronary artery
bypass graft surgery.

Berger K, Sander M, Spies CD, Weymann L, Bühner S, Lochs H, Wernecke KD, von
Heymann C.

Department of Anaesthesiology and Intensive Care Medicine,
Charité-Universitätsmedizin Berlin, Campus Virchow-Klinikum and Campus Charité
Mitte, Augustenburger Platz 1, 13353 Berlin, Germany.

BACKGROUND: /st> Cardiopulmonary bypass (CPB) impairs intestinal barrier function
and induces systemic inflammation after cardiac surgery. The objective of this
study was to evaluate the effect of profound haemodilution (haematocrit 19-21%)
during normothermic CPB on gastrointestinal permeability and cytokine release in 
comparison with a standard haemodilution (haematocrit 24-26%). METHODS: /st> This
was a prospective, controlled, randomized pilot trial of 60 patients without
gastrointestinal disease undergoing normothermic CPB (35.5-36 degrees C) for
coronary artery bypass graft surgery. Gastrointestinal permeability was measured 
by the triple-sugar technique (sucrose, lactulose, and mannitol excretion in
urine) before and after CPB. Interleukin (IL)-6, IL-10, and tumour necrosis
factor alpha (TNFalpha) were quantified using enzyme-linked immunosorbent assays.
RESULTS: /st> Data from 59 patients (19-21% haematocrit, n=28; 24-26%
haematocrit, n=31) were analysed. Data on gastrointestinal permeability were
available for 47 patients (19-21% haematocrit, n=23; 24-26% haematocrit, n=24),
blood samples for cytokine analysis from 59 patients. Mannitol excretion was
normal before and after surgery without significant differences between the
groups (after operation: 5.4% vs 2.9%, P=0.193). Lactulose and sucrose excretion 
was within a normal range before surgery and increased afterwards without
differences between the groups. IL-6, IL-10, and TNFalpha were elevated after
surgery, but there was no difference between the groups [IL-6 (P=0.78), IL-10
(P=0.74), and TNFalpha (P=0.67)]. CONCLUSIONS: /st> Profound haemodilution during
normothermic CPB brought about significant changes neither in intestinal
permeability nor in cytokine release. It may be concluded that a haematocrit of
19-21% during normothermic CPB does not impair intestinal barrier function and
cytokine response in patients without gastrointestinal comorbidity.

Ann Thorac Surg. 2009 Aug;88(2):551-7.

Funnel-tipped aortic cannula for reduction of atheroemboli.

White JK, Jagannath A, Titus J, Yoneyama R, Madsen J, Agnihotri AK.

Department of Surgery, Division of Cardiac Surgery, Massachusetts General
Hospital, Boston, Massachusetts 02114, USA.

BACKGROUND: Atheroemboli caused by aortic manipulation poses a risk for stroke in
patients undergoing cardiopulmonary bypass (CPB) surgery. One potential cause is 
the high velocity jet from aortic perfusion cannulae. This study describes the
flow patterns of a novel funnel-tip cannula designed to reduce emboli by
decreasing fluid velocity and resultant shear force on the aortic wall. METHODS: 
A funnel-tip cannula was constructed and compared with standard straight-tip
cannulae and the Dispersion (Research Medical Inc, Midvale, UT) and Sarns Soft
Flow (Terumo Cardiovascular Systems Corp, Ann Arbor, MI) cannulae. Pressure drop 
measurements were collected at 1 to 6 L/minute flows. Velocity flow profiles were
created using phase contrast magnetic resonance imaging. Absolute velocity was
measured in a phantom aorta at 5 L/minute flow. Each cannula was further studied 
in a synthetic model of an atherosclerotic aorta to determine the mass of
dislodged particulate matter generated at 2, 3, and 5 L/minute flows. RESULTS:
The funnel-tip cannula demonstrated significantly lower values (p < 0.05) in
pressure drop (55 mm Hg), exit velocity (309 cm/second, 167 cm/second for center 
axis and wall, respectively), and particulate dislodgement (0.15 +/- 0.05 g) than
other tested cannulae. The Soft Flow cannula generated the next lowest pressure
drop but exhibited twice the exit velocity and particulate dislodgement of the
funnel-tip cannula. The Dispersion cannula did not demonstrate a reduction in
velocity or particulate dislodgement compared with the standard straight-tip
cannulae. CONCLUSIONS: The results of this study suggest that a low-angled
funnel-tip cannula has favorable flow characteristics warranting further
investigation. Design development may reduce the risk of atheroemboli generation 
during CPB surgery.

Anesth Analg. 2009 Aug;109(2):320-30.

The efficacy of an intraoperative cell saver during cardiac surgery: a
meta-analysis of randomized trials.

Wang G, Bainbridge D, Martin J, Cheng D.

Department of Anesthesia and Perioperative Medicine, London Health Sciences
Centre, University of Western Ontario, London, Ontario, Canada.

BACKGROUND: Cell salvage may be used during cardiac surgery to avoid allogeneic
blood transfusion. It has also been claimed to improve patient outcomes by
removing debris from shed blood, which may increase the risk of stroke or
neurocognitive dysfunction. In this study, we sought to determine the overall
safety and efficacy of cell salvage in cardiac surgery by performing a systematic
review and meta-analysis of published randomized controlled trials. METHODS: A
comprehensive search was undertaken to identify all randomized trials of cell
saver use during cardiac surgery. MEDLINE, Cochrane Library, EMBASE, and abstract
databases were searched up to November 2008. All randomized trials comparing cell
saver use and no cell saver use in cardiac surgery and reporting at least one
predefined clinical outcome were included. The random effects model was used to
calculate the odds ratios (OR, 95% confidence intervals [CI]) and the weighted
mean differences (WMD, 95% CI) for dichotomous and continuous variables,
respectively. RESULTS: Thirty-one randomized trials involving 2282 patients were 
included in the meta-analysis. During cardiac surgery, the use of an
intraoperative cell saver reduced the rate of exposure to any allogeneic blood
product (OR 0.63, 95% CI: 0.43-0.94, P = 0.02) and red blood cells (OR 0.60, 95% 
CI: 0.39-0.92, P = 0.02) and decreased the mean volume of total allogeneic blood 
products transfused per patient (WMD -256 mL, 95% CI: -416 to -95 mL, P = 0.002).
There was no difference in hospital mortality (OR 0.65, 95% CI: 0.25-1.68, P =
0.37), postoperative stroke or transient ischemia attack (OR 0.59, 95% CI:
0.20-1.76, P = 0.34), atrial fibrillation (OR 0.92, 95% CI: 0.69-1.23, P = 0.56),
renal dysfunction (OR 0.86, 95% CI: 0.41-1.80, P = 0.70), infection (OR 1.25, 95%
CI: 0.75-2.10, P = 0.39), patients requiring fresh frozen plasma (OR 1.16, 95%
CI: 0.82-1.66, P = 0.40), and patients requiring platelet transfusions (OR 0.90, 
95% CI: 0.63-1.28, P = 0.55) between cell saver and noncell saver groups.
CONCLUSIONS: Current evidence suggests that the use of a cell saver reduces
exposure to allogeneic blood products or red blood cell transfusion for patients 
undergoing cardiac surgery. Subanalyses suggest that a cell saver may be
beneficial only when it is used for shed blood and/or residual blood or during
the entire operative period. Processing cardiotomy suction blood with a cell
saver only during cardiopulmonary bypass has no significant effect on blood
conservation and increases fresh frozen plasma transfusion.