TOP TEN SELECTED PAPERS
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November 2010 |
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Injury. 2010 Nov;41S2:S16-S23.
Pulmonary pathways and mechanisms regulating transpulmonary shunting into the
general circulation: An update.
Lovering AT, Elliott JE, Beasley KM, Laurie SS.
Department of Human Physiology, University of Oregon, Cardiopulmonary &
Respiratory Physiology Laboratory, Eugene, OR 97401, USA.
Embolic insults account for a significant number of neurologic sequelae following
many routine surgical procedures. Clearly, these post-intervention embolic events
are a serious public health issue as they are potentially life altering. However,
the pathway these emboli utilize to bypass the pulmonary microcirculatory sieve
in patients without an intracardiac shunt such as an atrial septal defect or
patent foramen ovale, remains unclear. In the absence of intracardiac routes and
large diameter pulmonary arteriovenous malformations, inducible large diameter
intrapulmonary arteriovenous anastomoses in otherwise healthy adult humans may
prove to be the best explanation. Our group and others have demonstrated that
inducible large diameter intrapulmonary arteriovenous anastomoses are closed at
rest but can open during hyperdynamic conditions such as exercise in more than
90% of healthy humans. Furthermore, the patency of these intrapulmonary
anastomoses can be modulated through the fraction of inspired oxygen and by body
positioning. Of particular clinical interest, there appears to be a strong
association between arterial hypoxemia and neurologic insults, suggesting a
breach in the filtering ability of the pulmonary microvasculature under these
conditions. In this review, we present evidence demonstrating the existence of
inducible intrapulmonary arteriovenous anastomoses in healthy humans that are
modulated by exercise, oxygen tension and body positioning. Additionally, we
identify several clinical conditions associated with both arterial hypoxemia and
an increased risk for embolic insults. Finally, we suggest some precautionary
measures that should be taken during interventions to keep intrapulmonary
arteriovenous anastomoses closed in order to prevent or reduce the incidence of
paradoxical embolism.
Artif Organs. 2010 Nov;34(11):1053-7.
Evaluation of Capiox FX05 oxygenator with an integrated arterial filter on
trapping gaseous microemboli and pressure drop with open and closed purge line.
Qiu F, Peng S, Kunselman A, Ündar A.
Department of Pediatrics, Penn State Hershey Pediatric Cardiovascular Research
Center, Penn State Milton S. Hershey Medical Center, Penn State Hershey College
of Medicine, Penn State Hershey Children’s Hospital, Hershey, PA 17033-0850, USA.
Gaseous microemboli (GME) remain a challenge for cardiopulmonary bypass (CPB)
because there is a positive correlation between microemboli exposure during CPB
and postoperative neurological injury. Thus, minimizing the number of GME
delivered to pediatric patients undergoing CPB procedures would lead to better
clinical outcomes. In this study, we used a simulated CPB model to evaluate the
effectiveness of capturing GME and the degree of membrane pressure drop for a new
membrane oxygenator, Capiox Baby FX05 (Terumo Corporation,Tokyo, Japan), which
has an integrated arterial filter with open and closed purge line.We used
identical components in this study as our clinical CPB circuit. Three emboli
detection and classification quantifier transducers were placed at prepump,
preoxygenator, and postoxygenator sites in the circuit.Two flow probes as well as
three pressure transducers were placed upstream and downstream of the oxygenator.
The system was primed with human blood titrated to 30% hematocrit with Lactated
Ringer’s solution.A bolus of air (1 mL) was injected in the prepump site under
nonpulsatile perfusion mode at three flow rates (500,750, and 1000 mL/min) and
with the purge line either open or closed. Six trials were performed for each
unique set-up for a total of 36 trials.All trials were conducted at 35°C. The
circuit pressure was kept constant at 100 mm Hg. Both the size and quantity of
microemboli detected at postoxygenator site were recorded for 5 min postair
injection. It was found that total counts of GME were significantly reduced with
the purge line open when compared to keeping the purge line closed (P < 0.0001 at
1000 mL/min). At all flow rates, most of the GME were under 20 microns in size.
In terms of microemboli greater than 40 microns, the counts were significantly
higher with the purge line closed compared to keeping the purge line open at flow
rates of 750 mL/min and 1000 mL/min (P < 0.01). At all flow rates,there is a tiny
difference of less than 1 mmHg in membrane pressure drop between keeping the
purge line open and closed, which is due to the small arteriovenous (A-V) shunt(P
< 0.001). These results suggest that the integrated arterial filter of the Capiox
FX05 oxygenator significantly improves the capturing of GME but has little impact
on membrane pressure drop.
Eur J Anaesthesiol. 2010 Nov 29. [Epub ahead of print]
Peri-operative complications in patients with left ventricular non-compaction.
Sviggum HP, Kopp SL, Rettke SR, Rehfeldt KH.
From the Department of Anesthesiology, Mayo Clinic College of Medicine,
Rochester, Minnesota, USA.
BACKGROUND AND OBJECTIVE: Left ventricular non-compaction (LVNC) is a relatively
uncommon cardiomyopathy. The implications of the presence of LVNC in the
peri-operative period are unknown. The objective of this study was to determine
the impact of LVNC on post-operative complications. METHODS: This retrospective
cohort study identified patients with an echocardiographic diagnosis of LVNC who
had an anaesthetic between 2001 and 2008. For each patient, all surgical
procedures during this time were reviewed. Patient demographics,
echocardiographic data, details of the procedure and anaesthetic and
peri-operative complications were recorded. We then compared the rate of
peri-operative complications in patients with LVNC with established complication
rates in the existing literature. RESULTS: During the study period, 60 patients
with LVNC underwent 220 procedures. Nineteen patients experienced a total of 25
complications, of which eight were directly related to the procedure and
considered unrelated to LVNC. Of the remaining 17 complications (in 15 patients),
there were 10 new arrhythmias, five respiratory complications, one seizure and
one episode of syncope. Nearly half (47%) of the complications followed open
cardiac surgery with cardiopulmonary bypass. All complications occurred in
association with procedures performed under general anaesthesia; none occurred in
patients undergoing regional anaesthesia or monitored anaesthesia care
(sedation). There was no long-term morbidity and no peri-operative mortality.
CONCLUSION: As the awareness and diagnosis of this condition increase,
anaesthesiologists will probably care for growing numbers of patients with LVNC.
We found that the incidence of post-operative complication in patients with LVNC
undergoing a variety of procedures was low and no different from the published
complication rates for other patients undergoing similar procedures.
Paediatr Anaesth. 2010 Nov 29. doi: 10.1111/j.1460-9592.2010.03464.x. [Epub ahead
of print]
Benefits and risks of red blood cell transfusion in pediatric patients undergoing
cardiac surgery.
Guzzetta NA.
Department of Anesthesiology, Emory University School of Medicine, Children's
Healthcare of Atlanta, Atlanta, GA, USA.
As the number of neonates and young infants undergoing cardiac surgery requiring
cardiopulmonary bypass (CPB) increases, red blood cell (RBC) transfusion will
continue to be an integral part of the practice of pediatric cardiac
anesthesiology. The decision of when to transfuse RBCs to these patients is
complex and influenced by multiple factors such as size, presence of cyanotic
heart disease, complexity of the surgical procedure, and the hemostatic
alterations induced by CPB. The known benefits of RBC transfusion include an
increase in the oxygen-carrying capacity of blood, improved tissue oxygenation,
and improved hemostasis. Unfortunately, there is no minimum hemoglobin level that
serves as a transfusion trigger for all pediatric patients undergoing cardiac
surgery. Physiologic signs such as tachycardia, hypotension, low mixed venous
oxygen saturation and increased oxygen extraction ratios can provide objective
evidence of the need to augment a given hemoglobin level. Nevertheless, the
benefits of RBC transfusion must be balanced against its risks and, in recent
years, RBC transfusion has been subjected to intense scrutiny. The adverse
consequences of RBC transfusion include the transmission of infectious diseases
and immune-mediated and nonimmune-mediated complications. Advances in donor
selection, infectious disease testing of donated blood, use of leukocyte
reduction and irradiation of blood in defined situations have improved the safety
of the blood supply in terms of infection transmission. However, a growing number
of prospective randomized clinical trials are finding an association between RBC
transfusion and an increased risk of morbidity and mortality even with the use of
leuko-reduced blood. Thus, it is becoming increasingly important that the
decision to transfuse RBCs be made with a thorough understanding of the
benefit-to-risk ratio. This review addresses the benefits and risks of RBC
transfusion, pertinent data acquired in the setting of congenital cardiac surgery
and techniques designed to minimize the need for RBC transfusion.
J Cardiothorac Surg. 2010 Nov 26;5(1):119. [Epub ahead of print]
Operative and early results of coronary artery bypass grafting in female patients
in different Body Mass Indexes.
Tokmakoglu H.
ABSTRACT: BACKGROUND: Female gender has been reported to be an independent risk
factor for coronary artery bypass grafting (CABG) in European System for Cardiac
Risk Evaluation. The effect of the body size on the CABG outcome is less clear.
There is ongoing debate about obesity as a risk factor for adverse outcomes after
cardiovascular procedures. The goal of this retrospective study is to evaluate
the in hospital and early postoperative outcomes in severe obese, obese and
normal-slightly obese female patients after CABG. METHODS: In a four year period
a total of 427 female patients underwent isolated CABG under cardiopulmonary
bypass. The patients were allocated into three groups according to the Body Mass
Index (BMI) as follows; group 1: severe obese patients; BMI>35, group 2: obese
patients; 30[less than or equal to]BMI[less than or equal to]35, group 3:
normal-slightly obese patients; BMI< 30 RESULTS: The patients in group 3 were
older than the group 1 and group 2 (65,6 +/- 8,3 year vs 63,01 +/- 8,0 and 63,57
+/- 8,4 year p< 0,05). In group 1 diabetic patients were more than in group 2 and
group 3 respectively ( 54,4% vs 43,4% and 40%, p<0,05). Urgent operation was more
in group 1 than in group 2 and 3 respectively (37,6% vs 17,2% and 21,2 % p<
0,05). The patients in group 3 had significantly greater postoperative drainage
at 24 h compared with values in group 1 and group 2 (647+/-142 ml vs. 539+/-169
ml and 582+/-133ml, p<0,05). Mortality rate in group 1 was 0,8%, 0% in group 2
and 1,2% in group 3 respectively. Wound problem has occured in 41 patients
(9,6%).The percentage of postoperative wound problems was higher in group 1 but
did not show statiscially difference. Following discharge a total of 43 (10,1%)
patients re-hospitalized within 30 days. Re-hospitalization rate was 16,1% in
group 1, 9,8% in group 2 and 6,5% in group 3 (p<0,05). CONCLUSION: This study may
give an aspect for evaluations of the inhospital-early mortality and morbidity
after CABG in female patients in different BMI. Severe obesity is not a risk
factor in-hospital mortality in female patients. However, severe obese female
patients appear to have more wound problems and re-hospitalization rate after
CABG compared to obese and normal- slightly obese patients.
Nitric Oxide. 2010 Nov 19. [Epub ahead of print]
Cardioprotective effects of hydrogen sulfide.
Szabó G, Veres G, Radovits T, Gero D, Módis K, Miesel-Gröschel C, Horkay F, Karck
M, Szabó C.
Department of Cardiac Surgery, University of Heidelberg, Im Neuenheiemer Feld
110, 69120 Heidelberg, Germany; Department of Cardiovascular Surgery, Semmelweis
University, Városmajor u. 68, 1122 Budapest, Hungary.
The gaseous mediator hydrogen sulfide (H(2)S) is synthesized mainly by
cystathionine ?-lyase in the heart and plays a role in the regulation of
cardiovascular homeostasis. Here we first overview the state of the art in the
literature on the cardioprotective effects of H(2)S in various models of cardiac
injury. Subsequently, we present original data showing the beneficial effects of
parenteral administration of a donor of H(2)S on myocardial and endothelial
function during reperfusion in a canine experimental model of cardiopulmonary
bypass. Overview of the literature demonstrates that various formulations of
H(2)S exert cardioprotective effects in cultured cells, isolated hearts and
various rodent and large animal models of regional or global myocardial ischemia
and heart failure. In addition, the production of H(2)S plays a role in
myocardial pre- and post-conditioning responses. The pathways implicated in the
cardioprotective action of H(2)S are multiple and involve K(ATP) channels,
regulation of mitochondrial respiration, and regulation of cytoprotective genes
such as Nrf-2. In the experimental part of the current article, we demonstrate
the cardioprotective effects of H(2)S in a canine model of cardiopulmonary bypass
surgery. Anesthetized dogs were subjected hypothermic cardiopulmonary bypass with
60min of hypothermic cardiac arrest in the presence of either saline (control,
n=8), or H(2)S infusion (1mg/kg/h for 2h). Left ventricular hemodynamic variables
(via combined pressure-volume-conductance catheter) as well as coronary blood
flow, endothelium-dependent vasodilatation to acetylcholine and
endothelium-independent vasodilatation to sodium nitroprusside were measured at
baseline and after 60min of reperfusion. Ex vivo vascular function and
high-energy phosphate contents were also measured. H(2)S led to a significantly
better recovery of preload recruitable stroke work (p<0.05) after 60min of
reperfusion. Coronary blood flow was also significantly higher in the H(2)S group
(p<0.05). While the vasodilatory response to sodium nitroprusside was similar in
both groups, acetylcholine resulted in a significantly higher increase in
coronary blood flow in the H(2)S-treated group (p<0.05) both in vivo and ex vivo.
Furthermore, high-energy phosphate contents were better preserved in the H(2)S
group. Additionally, the cytoprotective effects of H(2)S were confirmed also
using in vitro cell culture experiments in H9c2 cardiac myocytes exposed to
hypoxia and reoxygenation or to the cytotoxic oxidant hydrogen peroxide. Thus,
therapeutic administration of H(2)S exerts cardioprotective effects in a variety
of experimental models, including a significant improvement of the recovery of
myocardial and endothelial function in a canine model of cardiopulmonary bypass
with hypothermic cardiac arrest.
J Vasc Surg. 2010 Nov 17. [Epub ahead of print]
The learning curve of robot-assisted laparoscopic aortofemoral bypass grafting
for aortoiliac occlusive disease.
Novotný T, Dvor?ák M, Staffa R.
BACKGROUND:: Since the end of the 20th century, robot-assisted surgery has been
finding its role among other minimally invasive methods. Vascular surgery seems
to be another specialty in which the benefits of this technology can be expected.
Our objective was to assess the learning curve of robot-assisted laparoscopic
aortofemoral bypass grafting for aortoiliac occlusive disease in a group of 40
patients. METHODS:: Between May 2006 and January 2010, 40 patients (32 men, 8
women), who were a median age of 58 years (range, 48-75 years), underwent 40
robot-assisted laparoscopic aortofemoral reconstructions. Learning curve
estimations were used for anastomosis, clamping, and operative time assessment.
For conversion rate evaluation, the cumulative summation (CUSUM) technique was
used. Statistical analysis comparing the first and second half of our group, and
unilateral-to-bilateral reconstructions were performed. RESULTS:: We created 21
aortofemoral and 19 aortobifemoral bypasses. The median proximal anastomosis time
was 23 minutes (range, 18-50 minutes), median clamping time was 60 minutes
(range, 40-95 minutes), and median operative time was 295 minutes (range, 180-475
minutes). The 30-day mortality rate was 0%, and no graft or wound infection or
cardiopulmonary or hepatorenal complications were observed. During the median
18-month follow-up (range, 2-48 months), three early graft occlusions occurred
(7%). After reoperations, the secondary patency of reconstructions was 100%. Data
showed a typical short learning curve for robotic proximal anastomosis creation
with anastomosis and clamping time reduction. The operative time learning curve
was flat, confirming the procedure's complexity. There were two conversions to
open surgery. CUSUM analysis confirmed that an acceptable conversion rate set at
5% was achieved. Comparing the first and second half of our group, all recorded
times showed statistically significant improvements. Differences between
unilateral and bilateral reconstructions were not statistically significant.
CONCLUSIONS:: Our results show that the success rate of robot-assisted
laparoscopic aortofemoral bypass grafting is high and the complication rate is
low. Anastomosis creation, one of the main difficulties of laparoscopic bypass
grafting, has been overcome using the robotic operating system and its learning
curve is short. However, the endoscopic dissection of the aortoiliac segment
remains the most difficult part of the operation and should be addressed in
further development of the method to reduce the operative times. Long-term
results and potential benefits of this minimally invasive method have to be
verified by randomized controlled clinical trials.
Artif Organs. 2010 Nov;34(11):987-95. doi: 10.1111/j.1525-1594.2010.01133.x.
Inflammatory and hemostatic response to cardiopulmonary bypass in pediatric
population: feasibility of seriological testing of multiple biomarkers.
Agirbasli M, Nguyen ML, Win K, Kunselman AR, Clark JB, Myers JL, Undar A.
Department of Cardiology, Marmara University, Istanbul, Turkey.
Perioperative myocardial and cerebral damages are the major determinants of
postoperative morbidity and mortality in pediatric cardiac surgery.
Cardiopulmonary bypass (CPB) causes alterations in the levels of biomarkers
related to inflammation, tissue damage, and other tissue pathologies. Early and
accurate evaluation of inflammation and tissue damage would therefore be
clinically useful. Our objective is to assess the suitability of using
Multi-Analyte Profiling (MAP) (Rules Based Medicine, Austin, TX, USA) in
pediatric cardiac surgery as a potential surrogate marker of clinical outcome.
MAP technology platform allowed us to analyze 90 different biomarkers using only
100µL of plasma to detect any changes in the levels of 90 biomarkers. Plasma
samples (100µL) were collected at five different time points: 1. before midline
incision; 2. on CPB for 3-5min; 3. at the end of CPB; 4. 1h after CPB; and 5. 24h
after CPB. After removing the outliers, the average and standard deviation of the
values obtained from the 10 patients were calculated for each time point. The
average values of each biomarker at each time point were then compared to each
other and to the baseline. The pilot protocol included 10 patients (ages from 3
months to 4 years old) with similar Jenkins risks stratifications who underwent
nonpulsatile CPB. We detected changes in the levels of 90 biomarkers. Biomarkers
were assessed in groups. Myeloperoxidase (MPO) and pregnancy-associated plasma
protein A (PAPP-A) were the earliest markers to rise with 49- and 18-fold
increases 3-5min after the onset of CPB, respectively. The most striking increase
was noted in the heart-type fatty acid-binding protein (FABP) levels. FABP
increased 25, 193, 151, and 4-fold at time points 2, 3, 4, and 5, respectively.
Surges in the novel markers of injury were followed by the markers of
inflammation (i.e., C-reactive protein, interleukins) peaking at 24h after CPB.
This pilot study shows that it is possible to measure 90 different biomarkers
using only a very small sample of plasma to evaluate the effects of CPB. Novel
markers of tissue injury (FABP, PAPP-A, or MPO) are the earliest markers to rise.
Serial monitoring of multiple biomarkers may help to predict and improve outcomes
after pediatric cardiac surgery.
Perfusion. 2010 Nov 15. [Epub ahead of print]
Effects of peri-operative glucose levels on adverse outcomes in infants receiving
open heart surgery for congenital heart disease with cardiopulmonary bypass.
Lou S, Ding F, Long C, Liu J, Zhao J, Feng Z.
Department of Cardiopulmonary Bypass, Fuwai Hospital, Beijing, China.
OBJECTIVE: Studies designed to evaluate the association of hyperglycemia and
adverse events in pediatric patients receiving open cardiac surgery have yielded
inconsistent results. The aim of this retrospective, observational study was to
evaluate the effects of peri-operative glucose levels on adverse events in
infants receiving open-heart surgery with CPB. METHODS: From Nov 2009 through Dec
2009, 100 infants undergoing open-heart surgery were enrolled. All glucose values
during the operation and intensive care unit stay were documented. Metrics of
glucose control, including mean, peak and minimum glucose levels were calculated.
Hyperglycemia was defined as a mean glucose above 150mg/dl. Hypoglycemia was
defined as minimum glucose below 65mg/dl. Multivariable regression analyses were
used to determine relationships between these metrics of glucose control and a
composite morbidity-mortality outcome after controlling for multiple variables
known to influence early outcomes after congenital heart surgery. RESULTS:
According to our definition, 43 patients (43%) developed hyperglycemia and 9
patients (9%) developed at least one episode of hypoglycemia. A total of 58
patients reached the overall composite morbidity-mortality end point at some
point during the study period. After adjusting the effects of age, cross-clamp
time and pre-operative percutaneous oxygen saturation by multivariable analysis,
euglycemia, defined as mean glucose =150mg/dl, was found to be a significant
predictor for morbidity, with an odds ratio of 5.1(95% confidence interval
1.5-17.5). CONCLUSION: In contrast to adult critically ill patients, data from
the present study did not prove that hyperglycemia was detrimental to infants
receiving open-heart surgery with CPB. The existing literature and findings of
our present study warranted future clinical studies of strict glycemic control in
critically ill children, considering a more permissive glycemic range as a
desirable target.
Circulation. 2010 Nov 23;122(21):2123-30. Epub 2010 Nov 8.
Corticosteroids and outcome in children undergoing congenital heart surgery:
analysis of the pediatric health information systems database.
Pasquali SK, Hall M, Li JS, Peterson ED, Jaggers J, Lodge AJ, Marino BS, Goodman
DM, Shah SS.
Department of Pediatrics, Duke University Medical Center, Duke Clinical Research
Institute, Durham, NC 27715, USA. sara.pasquali@duke.edu
BACKGROUND: Children undergoing congenital heart surgery often receive
corticosteroids with the aim of reducing the inflammatory response after
cardiopulmonary bypass; however, the value of this approach is unclear.
METHODS AND RESULTS: The Pediatric Health Information Systems Database was used
to evaluate outcomes associated with corticosteroids in children (0 to 18 years
of age) undergoing congenital heart surgery at 38 US centers from 2003 to 2008.
Propensity scores were constructed to account for potential confounders: age,
sex, race, prematurity, genetic syndrome, type of surgery (Risk Adjustment in
Congenital Heart Surgery [RACHS-1] category), center, and center volume.
Multivariable analysis, adjusting for propensity score and individual covariates,
was performed to evaluate in-hospital mortality, postoperative length of stay,
duration of ventilation, infection, and use of insulin. A total of 46 730
children were included; 54% received corticosteroids. In multivariable analysis,
there was no difference in mortality among corticosteroid recipients and
nonrecipients (odds ratio, 1.13; 95% confidence interval, 0.98 to 1.30).
Corticosteroids were associated with longer length of stay (least square mean
difference, 2.18 days; 95% confidence interval, 1.62 to 2.74 days), greater
infection (odds ratio, 1.27; 95% confidence interval, 1.10 to 1.46), and greater
use of insulin (odds ratio, 2.45; 95% confidence interval, 2.24 to 2.67). There
was no difference in duration of ventilation. In analysis stratified by RACHS-1
category, no significant benefit was seen in any group, and the association of
corticosteroids with increased morbidity was most prominent in RACHS-1 categories
1 through 3.
CONCLUSION: In this observational analysis of children undergoing congenital
heart surgery, we were unable to demonstrate a significant benefit associated
with corticosteroids and found that corticosteroids may be associated with
increased morbidity, particularly in lower-risk patients.
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