TOP TEN SELECTED PAPERS - August 2008

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Pediatr Cardiol. 2008 Aug 26. [Epub ahead of print]

Effect of Open Heart Surgery with Cardiopulmonary Bypass on Peripheral Blood
Lymphocyte Apoptosis in Children.

Shi SS, Shi CC, Zhao ZY, Shen HQ, Fang XM, Tan LH, Zhang XH, Shi Z, Lin R, Shu Q.

Department of Thoracic and Cardiovascular Surgery, Children's Hospital, Medical
College, Zhejiang University, 310003, Hangzhou, China.

Children undergoing cardiopulmonary bypass (CPB) operations have an increased
risk for the development of immunosuppression and severe infection. Lymphocyte
apoptosis plays an important role in regulating immune responses. This study
aimed to investigate the effect of open heart surgery with CPB on peripheral
blood lymphocyte (PBL) apoptosis and the possible mechanism of lymphocyte
apoptosis in infants and young children. This study enrolled 20 consecutive
infants and children as a CPB group and 20 age-matched children who underwent
patent arterial duct closure without CPB as control subjects. Samples were taken 
from peripheral blood after induction of anesthesia (preoperatively) and again 24
h after the operations. The degree of apoptosis and the expression level of Fas
(CD95) on PBL were measured using flow cytometry. The percentage of lymphocyte
apoptosis significantly increased after surgery in both groups, but it was much
higher in the children with CPB than in those without CPB (14.46% +/- 4.83% vs.
7.33% +/- 1.43%; p < 0.01). The expression level of Fas in the individuals with
CPB was significantly higher than in those without CPB (52.80% +/- 8.80% vs.
37.82% +/- 6.32%; p < 0.01). As shown by the study findings, both surgical stress
and CPB can induce PBL apoptosis, which may lead to lymphopenia after open heart 
surgery with CPB for infants and young children.

Transplantation. 2008 Aug 27;86(4):515-20.

Lung transplantation for lymphangioleiomyomatosis: the French experience.

Reynaud-Gaubert M, Mornex JF, Mal H, Treilhaud M, Dromer C, Quétant S,
Leroy-Ladurie F, Guillemain R, Philit F, Dauriat G, Grenet D, Stern M.

The Divisions of Pulmonary Medicine and Thoracic Surgery, Hôpital Ste Marguerite,
Marseille, France. martine.reynaud@ap-hm.fr

BACKGROUND: Lymphangioleiomyomatosis (LAM) is a rare disease, leading in some
cases to end-stage respiratory failure. Lung transplantation (LT) represents a
therapeutic option in advanced pulmonary LAM. METHODS: We conducted a
retrospective multicenter study of 44 patients who underwent LT for LAM at 9
centers in France between 1988 and 2006. RESULTS: All patients were women with a 
mean age of 41+/-10 years at LT. There were 34 single-lung transplants and 11
bilateral transplants (one retransplantation). Prior clinical events related to
LAM were present in 75% of the patients and previous thoracic surgical procedures
were noted in 86.6% of cases. At the latest preoperative evaluation, 30 patients 
had an obstructive pattern (mean forced expiratory volume in 1 second: 26%+/-14% 
of predicted) and 15 had a combined restrictive and obstructive pattern, with a
mean KCO=27%+/-8.8% of predicted, PaO2=52.8+/-10.4 and PaCO2=42.6+/-9.8 mm Hg.
Intraoperative cardiopulmonary bypass was required in 13 cases. The length of
mechanical ventilation was 7.5+/-12.8 days. The median duration of follow-up was 
37 months. The 1, 2, 5, and 10 years survival rates were 79.6%, 74.4%, 64.7%, and
52.4%, respectively. Extensive pleural adhesions were found in 21 patients
leading to severe intraoperative hemorrhage. Postoperative LAM-related
complications were pneumothorax in the native lung in five patients, chylothorax 
in six, bronchial dehiscence or stenosis in seven. There were two cases of
recurrence of LAM. CONCLUSION: Despite a high morbidity mainly caused by previous
surgical interventions and disease-related complications, LT is a satisfactory
therapeutic option for end-stage respiratory failure in LAM.

Am J Surg. 2008 Aug 21. [Epub ahead of print]

Impact of intraoperative myocardial tissue acidosis on postoperative adverse
outcomes and cost of care for patients undergoing prolonged aortic clamping
during cardiopulmonary bypass.

Healey CM, Kumbhani DJ, Healey NA, Crittenden MD, Gibson SF, Khuri SF.

Cardiothoracic Surgery (112), VA Boston Healthcare System, 1400 VFW Pkwy., West
Roxbury, MA 02132, USA; Albany Medical College, Albany, NY, USA.

BACKGROUND: This study examined the impact of intraoperative myocardial acidosis 
and adverse postoperative outcomes on the cost of cardiac surgical care. METHODS:
Myocardial tissue pH corrected to 37 degrees C (pH(37C)) was measured in 162
patients with cross-clamp (XC) duration of 119 minutes or longer. Perioperative
data and outcomes were collected prospectively. The Veterans Affairs cost
accounting system was used to determine the cost of care in a subset of 57
patients. RESULTS: Long XC duration was associated with significantly increased
acidosis and adverse postoperative outcomes. The cost of care for patients with
adverse outcomes was increased by 110% (P < .0001). Patients with acidosis at the
end of reperfusion had significantly (P = .0470) increased costs of care. End
reperfusion of myocardial tissue pH(37C) of less than 7.0, diabetes mellitus, and
body surface area were significant determinants of postoperative adverse
outcomes. CONCLUSIONS: Intraoperative myocardial acidosis is a determinant of
postoperative adverse outcomes and cost in cardiac surgery. Reducing XC duration 
and improving intraoperative myocardial protection should improve outcomes and
reduce cost.

Ann Thorac Surg. 2008 Sep;86(3):897-902; discussion 897-902.

Repeat sternotomy in congenital heart surgery: no longer a risk factor.

Morales DL, Zafar F, Arrington KA, Gonzalez SM, McKenzie ED, Heinle JS, Fraser CD
Jr.

Michael E. DeBakey Department of Surgery, Division of Congenital Heart Surgery,
Baylor College of Medicine, Houston, Texas, USA.
dlmorale@texaschildrenshospital.org

BACKGROUND: The risk of repeat sternotomy (RS) is often taken into account when
making clinical management decisions. Current literature on RS suggests a risk of
approximately 5% to 10% for major morbidity. We sought to establish the true risk
of RS in a contemporary pediatric series. METHODS: All RS between October 2002
and August 2006 were analyzed (602 RS in 558 patients). Median age was 3.6 years 
(range, 0.1 to 45.1); weight, 14.2 kg (2.0 to 112.2). Operations performed at RS 
were Glenn 22% (131), Fontan 21% (129), aortic valve repair/replacement 12% (72),
right ventricle-pulmonary artery conduit 11% (67), Rastelli 7% (39), heart
transplant 5% (31), and other 22% (133). Forty-seven percent of patients (280)
had single-ventricle physiology. Incidence of second sternotomy was 67% (406),
third 28% (166), fourth 4% (24), fifth 0.8% (5), and sixth 0.2% (1). A major
injury upon RS was defined as one causing hemodynamic instability requiring
vasopressor support or emergent transfusion; femoral cannulation or emergent
cardiopulmonary bypass; and any morbidity. A minor injury is any other injury
during RS. RESULTS: The incidence of a major injury was not different between RS 
(0.3%; 2 of 602) and first-time sternotomy (0%; 0 of 1,274; p > 0.1). Incidence
of a minor injury was 0.66% (4 of 602). No injury resulted in hemodynamic
instability, neurologic injury, or death. Two patients (0.3%) required a
nonemergent blood transfusion secondary to injury. (Nonemergent was defined as
adminstration rate of less than 0.2 cc/kg/min and less than 10 cc/kg in total.)
Femoral cannulation was performed in 4 of 602 RS cases (< 0.6%). Sternal wound
infection was 0.5% (3 of 602); reoperation for postoperative bleeding was 1% (8
of 602). Median intensive care unit stay was 3 days (1 to 174); median hospital
stay was 7 days (1 to 202). Hospital survival was 98%. CONCLUSIONS: Repeat
sternotomy can represent a negligible risk of injury and of subsequent morbidity 
or mortality. Therefore, the choice of management strategies for patients should 
not be affected by the need for RS.

Interact Cardiovasc Thorac Surg. 2008 Aug 21. [Epub ahead of print]

Bicarbonate buffered ultrafiltration leads to a physiologic priming solution in
pediatric cardiac surgery.

Osthaus WA, Sievers JH, Breymann T, Suempelmann R.

Hannover Medical School, Germany.

Pediatric cardiopulmonary bypass (CPB) involves a high ratio of priming blood
volume to patient blood volume. The composition of packed red blood cells (RBCs) 
is very unphysiological in terms of acid-base, electrolyte and metabolite values.
Therefore, we tested the hypothesis whether ultrafiltration of the prime and
replacement with bicarbonate buffered hemofiltration solution (BB-HS) is
sufficient for reducing the metabolic load and reaching a physiologic state. For 
planned surgery of congenital heart defects with cardiopulmonary bypass, twenty
CPB circuits were primed with BB-HS, gelatin and 1 unit of RBCs. The fluid was
hemofiltrated using an ultrahemofilter at 300 ml/min until approximately 1000 ml 
of ultrafiltrate was restored with BB-HS. Blood gas analyses were obtained from
the priming blood, once before and once after bicarbonate buffered
ultrafiltration (BBUF). The measured substrates decreased significantly (p<0.001)
after BBUF (glucose from 13.0+/-2.6 to 6.3+/-1.0 and lactate from 3.8+/-1.5 to
2.3+/-1.0 mmol/l). Acid-base parameters increased (p<0.001) to normal or high
normal values (pH from 7.01+/-0.09 to 7.68+/-0.12; HCO3 from 12.1+/-2.4 to
25.4+/-3.6 mmol/l and BE from -15.4+/-3.6 to -0.8+/-3.7 mmol/l). Even the
electrolytes sodium, potassium and calcium changed significantly (p<0.001) toward
the physiologic range. BBUF is an efficient method of reducing the metabolic load
of priming. After BBUF, even the electrolyte and acid-base balance reached a
physiologic state, which is important for minimizing electrolyte and acid-base
disturbances after initiation of CPB. Keywords: Cardiopulmonary bypass;
Congenital heart disease; Ultrafiltration; Priming volume; Metabolic load.

J Thorac Cardiovasc Surg. 2008 Aug;136(2):436-41.

Robotic mitral valve repairs in 300 patients: a single-center experience.

Chitwood WR Jr, Rodriguez E, Chu MW, Hassan A, Ferguson TB, Vos PW, Nifong LW.

Department of Cardiovascular Sciences, East Carolina Heart Institute, East
Carolina University, Greenville, NC 27858, USA. chitwoodw@ecu.edu

OBJECTIVES: Mitral valve repair is the standard therapy for patients with
degenerative (myxomatous) disease and severe mitral regurgitation. Robotic mitral
valve repair provides the least-invasive surgical approach. We report the largest
single-center robotic mitral valve repair experience. METHODS: Between May 2000
and November 2006, 300 patients underwent a robotic mitral valve repair (daVinci 
Surgical System; Intuitive Surgical, Inc, Sunnyvale, Calif). All operations were 
done with 3- to 4-cm right intercostal access, transthoracic aortic occlusion,
and peripheral cardiopulmonary bypass. Repairs included 1 or a combination of
trapezoidal/triangular leaflet resections, sliding plasties, chordal
transfers/replacements, edge-to-edge approximations, and ring annuloplasties.
Echocardiographic and survival follow-up were 93% and 100% complete,
respectively. RESULTS: There were 2 (0.7%) 30-day mortalities and 6 (2.0%) late
mortalities. No sternotomy conversions or mitral valve replacements were
required. Immediate postrepair echocardiograms showed the following degrees of
mitral regurgitation: none/trivial, 294 (98%); mild, 3 (1.0%); moderate, 3
(1.0%); and severe, 0 (0.0%). Complications included 2 (0.7%) strokes, 2
transient ischemic attacks, 3 (1.0%) myocardial infarctions, and 7 (2.3%)
reoperations for bleeding. The mean hospital stay was 5.2 +/- 4.2 (standard
deviation) days. Sixteen (5.3%) patients required a reoperation. Mean
postoperative echocardiographic follow-up at 815 +/- 459 (standard deviation)
days demonstrated the following degrees of mitral regurgitation: none/trivial,
192 (68.8%); mild, 66 (23.6%); moderate, 15 (5.4%); and severe, 6 (2.2%).
Five-year Kaplan-Meier survival was 96.6% +/- 1.5%, with 93.8% +/- 1.6% freedom
from reoperation. CONCLUSIONS: Robotic mitral valve repair is safe and is
associated with good midterm durability. Further long-term follow-up is
necessary.

J Thorac Cardiovasc Surg. 2008 Aug;136(2):335-42. Epub 2008 Jun 2.

Remote ischemic preconditioning elaborates a transferable blood-borne effector
that protects mitochondrial structure and function and preserves myocardial
performance after neonatal cardioplegic arrest.

Wang L, Oka N, Tropak M, Callahan J, Lee J, Wilson G, Redington A, Caldarone CA.

Division of Cardiovascular Research, Hospital for Sick Children, Toronto,
Ontario, Canada.

OBJECTIVE: Remote ischemic preconditioning is known to elicit production of a
blood-borne cardioprotective factor that is infarct sparing in models of
ischemia-reperfusion injury and myocardial damage reducing after cardiopulmonary 
bypass in human subjects. The mechanism of protection remains incompletely
understood. In this study, we examined effects on mitochondrial structure and
function in a noninfarct model of cardioplegic arrest. METHODS: Explanted
neonatal rabbit hearts were mounted in a Langendorff preparation and perfused
with dialysate of blood taken from sham-treated or remotely preconditioned
rabbits. Each heart was subsequently subjected to 1-hour cardioplegic arrest and 
30-minute reperfusion periods, during which hemodynamic responses were measured. 
Mitochondria were isolated for structural and functional measurements. RESULTS:
Relative to hearts with sham-treated dialysate, myocardial performance (systolic 
pressure, maximum positive and negative first derivatives of left ventricular
pressure, and left ventricular end-diastolic pressure) was better preserved with 
dialysate from preconditioned rabbits. Similarly, mitochondria isolated from
hearts with dialysate from preconditioned rabbits showed preserved respiration at
complex I and IV in the electron transport chain (P < .01 and P < .05,
respectively). Mitochondrial outer membrane integrity was also preserved, with
diminished sensitivity of mitochondrial respiration to exogenous cytochrome c (P 
< .01) and less cytosolic diffusion of cytochrome c (P < .01). Mitochondrial
resistance to calcium-mediated mitochondrial permeability transition pore opening
was not affected. CONCLUSION: The cardioprotective factor in plasma dialysate
after remote preconditioning preserves mitochondrial structure and function in a 
noninfarct cardioplegic arrest model. This protection is associated with
preservation of global myocardial performance.

Eur J Cardiothorac Surg. 2008 Sep;34(3):648-52. Epub 2008 Jul 30.

High colloid oncotic pressure priming of cardiopulmonary bypass in neonates and
infants: implications on haemofiltration, weight gain and renal function.

Loeffelbein F, Zirell U, Benk C, Schlensak C, Dittrich S.

Department of Paediatric Cardiology and Congenital Heart Disease, University
Children's Hospital, Mathildenstrasse 1, D-79106 Freiburg, Germany.

Objective: To evaluate the influence of high colloid oncotic pressure (COP)
priming of cardiopulmonary bypass (CPB) on fluid balances, haemofiltration,
capillary leakage and renal function in neonates and infants. Methods: Twenty
neonates or infants underwent heart surgery using CPB and were randomised in two 
groups. For group 1 (FFP-group) a blood priming with fresh frozen plasma (FFP,
low oncotic pressure) was chosen, for group 2 (HA-group) a blood priming
containing FFP and human albumin 20% (HA) to realise higher oncotic pressures was
substituted. All patients were monitored before, during and 6h after CPB. We
measured weights, fluid balances, transfusion volumes, colloid oncotic pressures,
inflammatory parameters (c-reactive protein, interleukin-6, interleukin-8,
thrombocytes, leucocytes) and renal function (creatinine clearances, renal
protein losses). Results: Patient's demographics and operational procedures were 
comparable in both groups with no further differences in operation procedures
regarding palliation or correction. Colloid oncotic pressures of the priming
solutions were higher in the HA-group (28mmHg+/-4.9) than in the FFP-group
(6mmHg+/-1.3, p<0.001). Relative weight gain as a marker of capillary leakage in 
the HA-group (2%+/-4.5) was significantly lower 6h post CPB than in the FFP-group
(8%+/-8.0, p=0.015). Haemofiltration rates were higher in the HA-group
(569ml+/-197 vs 282ml+/-157, p=0.002) on CPB. There were no differences of
creatinine clearances 6h after the end of CPB. Renal protein losses were elevated
in both groups without any inter-group differences during and 6h after CPB.
Conclusion: Addition of concentrated human albumin to priming fluids in
paediatric cardiac surgery leads to less weight gain even after CPB.
Supplementing paediatric patients undergoing cardiac surgery with concentrated
human albumin does not affect renal function more severely than in paediatric
patients undergoing cardiac surgery on CPB with blood priming.

ASAIO J. 2008 Jul-Aug;54(4):432-5.

"Stolen" blood flow: effect of an open arterial filter purge line in a simulated 
neonatal CPB model.

Wang S, Miller A, 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.

The purpose of this study was to evaluate the effect of different flow rates and 
pressures on the degree of shunting of blood flow by the arterial filter purge
line in a simulated neonatal cardiopulmonary bypass circuit. The circuit was
primed with heparinized bovine blood (hematocrit 24%) and postfilter pressure was
varied from 60-180 mm Hg (20 mm Hg increments) using a Hoffman clamp. Trials were
conducted at flow rates ranging from 200-600 ml/min (100 ml/min increments).
During trials conducted at a postfilter pressure of 60 mm Hg, 42.6% of blood flow
was shunted through the purge line at a flow rate of 200 ml/min, whereas only
12.8% of flow was diverted at a flow rate 600 ml/min. During trials conducted at 
a postfilter pressure of 180 mm Hg, 82.8% of blood flow at 200 ml/min and 25.9%
of blood flow at 600 ml/min was diverted through the open arterial purge line.
The results of this study confirm that a significant amount of flow is diverted
away from the patient when the arterial purge line is open. Shunting of blood
flow through the arterial purge line could result in less effective tissue
perfusion, particularly at low flow rates and high postfilter pressures. To
minimize hypoperfusion injury, a flow probe (distal to the arterial filter) may
be used to monitor real-time arterial flow in the setting of an open arterial
filter purge line.

Ann Thorac Surg. 2008 Aug;86(2):441-6; discussion 446-7.

Axillary cannulation significantly improves survival and neurologic outcome after
atherosclerotic aneurysm repair of the aortic root and ascending aorta.

Etz CD, Plestis KA, Kari FA, Silovitz D, Bodian CA, Spielvogel D, Griepp RB.

Department of Cardiothoracic Surgery, Mount Sinai School of Medicine, New York,
New York 10029, USA. christian.etz@mountsinai.org

BACKGROUND: The impact of axillary artery cannulation (AXC) on survival and
neurologic outcome after operation for ascending aortic disease was
retrospectively evaluated. METHODS: We reviewed 869 patients with ascending
aorta/root repairs (1995 to 2005), principally for atherosclerotic and
degenerative aneurysms and chronic and acute type A dissections. Arterial
cannulation was through the ascending aorta (AAC) in 157 patients, the femoral
artery (FAC) in 261, and the right axillary artery (AXC) in 451. Patients
cannulated at different sites were compared for preoperative comorbidities and
outcomes (mortality and stroke) for each cause. RESULTS: Of the 122 patients with
atherosclerotic aneurysms, 66 with right AXC had significantly better outcomes (p
= 0.02): 64 of 66 survived vs 24 of 26 with FAC and 27 with 30 of AAC; no strokes
occurred (vs 2 of 26 with FAC and 4 of 30 with AAC). No significant advantage for
AXC was found with ascending aortic operation in 495 degenerative aneurysms, 106 
chronic, or 65 acute type A dissections, 41 patients with endocarditis, or in 18 
with aneurysms of other causes; AXC was associated with a significantly better
outcome (p = 0.05) in the 869 patients taken together. CONCLUSIONS: AXC resulted 
in superior survival and neurologic outcome in patients with atherosclerotic
aneurysms and a marginally better outcome than with cannulation at other sites
during proximal aortic procedures for all causes. This study supports AXC in
patients with atherosclerotic disease who require complex cardiothoracic
operations and in patients requiring proximal aortic intervention regardless of
cause.