TOP TEN SELECTED PAPERS - September 2008

1

Kardiol Pol. 2008 Sep;66(9):925-931.

Cost-effectiveness of mini-circuit cardiopulmonary bypass in newborns and infants
undergoing open heart surgery.

Mozol K, Haponiuk I, Byszewski A, Maruszewski B.

The Children's Memorial Health Institute, ul. Dzieci Polskich 20, 04-730
Warszawa, tel.: +48 22 815 70 00, e-mail: kmozol@doctors.org.uk.

Background and aim: Miniaturisation of the extracorporeal circuit is a current
trend in modern paediatric cardiac surgery. Many investigators stress that
reduction of priming volume and artificial surface area of extracorporeal
circulation could lead to clinical and economic benefits. The aim of this paper
was to evaluate the costs of mini-circuit use in infants undergoing open heart
surgery. Methods: We assessed post-operative course and cost of treatment in 60
infants undergoing open heart surgery. This group was prospectively randomised
and divided into 2 equal subgroups: with miniaturised (group M) and conventional 
cardio pulmonary bypass circuits (group C). The study groups were clinically
comparable. Surgical complications, duration of hospitalisation and cost of
postoperative treatment were assessed in both groups. Results: Miniaturisation of
the extracorporeal circuit led to a significant reduction of priming volume and
artificial surface area (by 46.6% and 68.8% respectively, p=0.0000001).
Post-operative cardio-respiratory insufficiency (2 vs. 8, p=0.038), and infection
(3 vs. 9, p=0.049) occurred less often in children from group M. Hospital stay
was significantly shorter in group M. Total cost of treatment was significantly
lower in children from group M (median: 4361.4 vs. 6660.5 euro, p=0.037).
Conclusions: Miniaturisation of the extracorporeal circulation significantly
improve post-operative outcome in infants undergoing open heart surgery. The
mini-circuit significantly reduces cost of treatment in small children undergoing
open heart surgery.

J Extra Corpor Technol. 2008 Sep;40(3):206-14.

Methylene blue-induced methemoglobinemia during cardiopulmonary bypass? A case
report and literature review.

McRobb CM, Holt DW.

Perfusion Services, Duke University Hospital, 2301 Erwin Rd, Durham, NC 27710,
USA. cmcrobb@hotmail.com

The guanylate cyclase (GC) and inducible nitric oxide (iNOS) inhibitor methylene 
blue (MB) has been used in cardiac surgery patients for the treatment of a
variety of conditions. Methylene blue has been successfully used for the
prevention and treatment of vasoplegia syndrome (VS) in patients undergoing
cardiac surgery with cardiopulmonary bypass (CPB). Vasoplegia syndrome occurs in 
up to 10% of cardiac surgery patients and is associated with poor clinical
outcomes. Vasoplegia syndrome is described along with the results of studies that
have shown benefits of MB in the treatment of VS. These studies include the use
of MB prior to CPB, when added to the CPB prime and when given into the CPB
circuit during the operation. We report a case of emergency CPB on a 55-year-old 
male with bacterial endocarditis, scheduled for an AVR/MVR who arrested on
arrival to the operating room. Once on CPB the patient developed a profound
hypotension despite normal to high pump flows, with low systemic vascular
resistance (SVR), which was refractory to vasopressors--consistent with a
diagnosis of VS. Unbeknownst to the perfusionist, the patient was treated with MB
which was immediately followed by an apparent sudden arterial desaturation,
despite oxygenator ventilation with 100% oxygen (O2), and development of severe
metabolic acidosis. Troubleshooting the cause of the apparent desaturation and
eventual diagnosis of a false indication of arterial oxygen desaturation and
methemoglobinemia (MHgb) due to MB injection is described. Methemoglobinemia is
explained as well as its presentation and treatment with MB. The importance of
intraoperating room communication and knowledge of drug effects are discussed.

J Cardiothorac Vasc Anesth. 2008 Sep 22. [Epub ahead of print]

Neurocognitive Function in Patients Undergoing Coronary Artery Bypass Graft
Surgery With Cardiopulmonary Bypass: The Effect of Two Different Rewarming
Strategies.

Sahu B, Chauhan S, Kiran U, Bisoi A, Lakshmy R, Selvaraj T, Nehra A.

Department of Cardiac Anesthesiology, Cardiothoracic Centre, All India Institute 
of Medical Sciences, New Delhi, India.

OBJECTIVE: Hypothermia followed by rewarming during cardiopulmonary bypass can
lead to cerebral hyperthermia, which has been implicated as 1 of the causes for
postoperative deterioration in neurocognitive function in patients undergoing
coronary revascularization. Hence, the authors studied the effects of 2 different
rewarming strategies on postoperative neurocognitive function in adult patients
undergoing coronary artery bypass graft surgery with the aid of cardiopulmonary
bypass. DESIGN: This was a randomized clinical trial. SETTING: A cardiothoracic
center of a tertiary level referral, teaching hospital. PARTICIPANTS: A total of 
80 adult patients aged 45 to 70 years undergoing elective primary isolated
coronary artery bypass graft surgery with cardiopulmonary bypass under moderate
hypothermia at 30 degrees C were included in this study. INTERVENTIONS: The
patients were randomly allocated into 2 groups of 40 each. In group A, patients
were rewarmed to a nasopharyngeal temperature of 37 degrees C; whereas, in group 
B, patients were rewarmed to a nasopharyngeal temperature of 33 degrees C before 
weaning off bypass. The anesthetic and bypass management were standardized for
both groups. MEASUREMENTS: All patients were assessed for neurocognitive function
preoperatively and on the fifth postoperative day using the Post Graduate
Institute Memory Scale. The amount of blood loss and need for blood and blood
product transfusion postoperatively, the need for pacing, increased inotrope or
vasodilator use, and time to extubation were also noted. Serum S100beta levels
were measured after anesthetic induction and at 24 hours postoperatively. The
jugular venous oxygen saturation and oxygen tension were noted at 30 degrees C
and at the end of full rewarming (ie, at 37 degrees C or 33 degrees C,
respectively, in the 2 groups). RESULTS: There was a significant deterioration in
neurocognitive function postoperatively as compared with preoperative function in
patients of group A (37 degrees C). This was associated with higher S100beta
levels 24 hours postoperatively in group A (37 degrees C) compared with group B
(33 degrees C) patients. Also, there was a significant decrease in jugular venous
oxygen saturation in group A (37 degrees C) as compared with group B (33 degrees 
C) at the end of rewarming. The time to extubation was longer in group B (33
degrees C). No significant differences were noted in the amount of postoperative 
blood loss, blood and blood product use, inotrope or vasodilator use, and the
need for pacing. CONCLUSION: Weaning from CPB at 33 degrees C may be a simple and
useful strategy to lower the postoperative impairment of neurocognitive function 
and may be used as a tool to decrease morbidity after coronary revascularization.

Congenit Heart Dis. 2008 Sep;3(5):341-6.

Aortopulmonary window in adults: diagnosis and treatment of late-presenting
patients.

Aggarwal SK, Mishra J, Sai V, Iyer VR, Panicker BK.

Department of Cardiology, Sri Sathya Sai Institute of Higher Medical Sciences,
Prashantigram, India. suneilaggarwal@doctors.net.uk

OBJECTIVES: Aortopulmonary window is an uncommon condition, particularly so in
adulthood because it is usually fatal in infancy or childhood if untreated. Very 
few cases of those who have survived to adulthood and been operated on
successfully have been described. Our study aimed to provide clinical,
investigative, surgical, and outcome details of such patients. DESIGN AND
SETTING: Retrospective study of consecutive adult patients with aortopulmonary
window treated at a tertiary charitable cardiovascular institute in South India
between 1996 and 2006. RESULTS: Six adult patients successfully underwent
aortopulmonary window closure. Five of the six patients had been correctly
diagnosed on echocardiography, while one was only diagnosed after cardiac
catheterization for unexplained pulmonary arterial hypertension. Four of the
patients had large defects with severe pulmonary arterial hypertension, with
pulmonary vascular resistance index (PVRI) ranging from 5.2 to 15.9 at baseline. 
All showed significant reversibility with oxygen administration, with PVRI on
oxygen falling to between 0.6 and 2.2. These patients successfully underwent
cardiopulmonary bypass. The other two patients with small lesions underwent
ligation off-pump. There was no early or late mortality among these patients. All
were in New York Heart Association class I, on follow-up ranging from 3 months to
8 years. CONCLUSIONS: Aortopulmonary window may rarely present in adulthood. The 
diagnosis can usually be made by careful echocardiography alone. Even in the
presence of severe pulmonary arterial hypertension, if a significant
reversibility in pulmonary vascular resistance can be demonstrated with oxygen,
the condition can be successfully corrected with good long-term outcomes.

Eur J Cardiothorac Surg. 2008 Sep 29. [Epub ahead of print]

Minimally invasive mitral valve surgery: a systematic review and meta-analysis.

Modi P, Hassan A, Chitwood WR Jr.

East Carolina Heart Institute, Greenville, NC, USA.

The mitral valve has been traditionally approached through a median sternotomy.
However, significant advances in surgical optics, instrumentation, tissue
telemanipulation, and perfusion technology have allowed for mitral valve surgery 
to be performed using progressively smaller incisions including the
minithoracotomy and hemisternotomy. Due to reports of excellent results,
minimally invasive mitral valve surgery has become a standard of care at certain 
specialized centers worldwide. This meta-analysis quantifies the effects of
minimally invasive mitral valve surgery on morbidity and mortality compared with 
conventional mitral surgery and demonstrates equivalent perioperative mortality
(1641 patients, odds ratio (OR) 0.46, 95% confidence interval 0.15-1.42, p=0.18),
reduced need for reoperation for bleeding (1553 patients, OR 0.56, 95% CI
0.35-0.90, p=0.02) and a trend towards shorter hospital stays (350 patients,
weighted mean difference (WMD) -0.73, 95% CI -1.52 to 0.05, p=0.07). These
benefits were evident despite longer cardiopulmonary bypass (WMD 25.81, 95% CI
13.13-38.50, p<0.0001) and cross-clamp times (WMD 20.91, 95% CI 8.79-33.04,
p=0.0007) in the minimally invasive group. Case-control studies show consistently
less pain and faster recovery compared to those having a conventional approach.
Data for minimally invasive mitral valve surgery after previous cardiac surgery
are limited but consistently demonstrate reduced blood loss, fewer transfusions
and faster recovery compared to reoperative sternotomy. Long-term follow-up data 
from multiple cohort studies are also examined revealing equivalent survival and 
freedom from reoperation. Thus, current clinical data suggest that minimally
invasive mitral valve surgery is a safe and a durable alternative to a
conventional approach and is associated with less morbidity.

Eur J Cardiothorac Surg. 2008 Sep 29. [Epub ahead of print]

Reduced pulmonary inflammatory response during cardiopulmonary bypass: effects of
combined pulmonary perfusion and carbon monoxide inhalation.

Goebel U, Siepe M, Mecklenburg A, Doenst T, Beyersdorf F, Loop T, Schlensak C.

Department of Anesthesiology and Critical Care Medicine, University Medical
Center Freiburg, Germany.

Objective: Pulmonary inflammation induced by cardiopulmonary bypass (CPB) is one 
of the main causes for lung injury after cardiac surgery. Pulmonary perfusions as
well as carbon monoxide (CO) inhalation are known to reduce the inflammatory
reaction of the lung. We hypothesized that a combination of pulmonary perfusion
and carbon monoxide inhalation leads to an even stronger reduction of the lung
inflammation. Methods: Pigs (n=7 per experimental group) were randomized to sham 
operation (SHAM), conventional CPB (CPB), inhalation of CO (CPB+CO, 250ppm),
pulmonary perfusion (CPB+PP) or pulmonary perfusion plus inhalation of CO
(CPB+PP+CO). Various cytokine levels (TNF-alpha, IL-1, IL-6, and IL-10) and
caspase-3 activity were measured using enzyme-linked immunosorbent assay (ELISA).
Transcription factor activity was analyzed via electrophoretic mobility shift
assay (EMSA). Blood gases and hemodynamics were measured continuously. A p value 
<0.05 assessed by Holm-Sidak method was considered statistically significant.
Results: Hemodynamic parameters and blood gas analysis showed no significant
differences between the groups. While IL-1 protein expression was comparable
between the groups, TNF-alpha (478+/-58 vs 869+/-95pg/ml; p<0.001) and IL-6
protein levels in the lung (256+/-82 vs 936+/-76pg/ml; p<0.001) showed a
significant inhibition in the CPB+PP+CO group at 120min post-bypass time compared
to the CPB group. The cytokine levels were comparable to the CPB+PP and CPB+CO
group. IL-10 protein expression (325+/-47 vs 65+/-27pg/ml; p<0.05) was
significantly higher in the CO-treated compared to CPB+PP and CPB-treated animals
at 120min post-bypass. Activation of the transcription factors NF-kappaB and AP-1
showed a CO-mediated induction compared to the CPB or CPB+PP group. Caspase-3
activity revealed a CO-dependent, significant inhibition in CO and
CPB+PP+CO-treated animals compared to CPB animals (p<0.05). Conclusion: The
combination of pulmonary perfusion and inhalative carbon monoxide inhibits
CPB-mediated pulmonary inflammation as well as pulmonary apoptosis stronger than 
pulmonary perfusion or carbon monoxide alone.

ASAIO J. 2008 Sep-Oct;54(5):538-41.

Comparison of two different blood pumps on delivery of gaseous microemboli during
pulsatile and nonpulsatile perfusion in a simulated infant CPB model.

Wang S, Kunselman AR, Myers JL, Undar A.

Department of Pediatrics, Pediatric Cardiac Research Laboratories, 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 compare two different blood pumps (Jostra roller
pump vs. Medos deltastream DP1 rotary pump) on delivery of gaseous microemboli
during pulsatile and nonpulsatile perfusion in a simulated infant cardiopulmonary
bypass (CPB) model. The Jostra and Medos pump were used in parallel pattern. The 
circuit was primed with lactated ringer's solution (700 ml) and the postfilter
pressure was maintained at 100 mm Hg. Three transducers (postpump, postoxygenator
and postfilter sites) of the Emboli Detection and Classification (EDAC)
Quantifier were inserted into the CPB circuit to detect and classify gaseous
microemboli. Trials were conducted at flow rates ranging from 500 to 1250 ml/min 
(250 ml/min increments). The arterial filter purge line was kept open during all 
trials. After injecting 20 ml air into the venous line, 2-minute segments of data
were recorded simultaneously through three transducers. This entire process was
repeated six times for each unique combination of blood pump, flow rate and
perfusion mode, yielding a total of 96 experiments. Independent of perfusion mode
and flow rate, Medos pump delivered less gaseous microemboli than Jostra pump at 
the postpump site, but only at 1,250 ml/min of pump flow rate the differences
reached statistical significance (p < 0.01). There was no difference in delivery 
at the postfilter site. Compared with nonpulsatile flow, pulsatile flow
transferred significantly more gaseous microemboli at the postpump site at 1,250 
ml/min of pump flow rate in both groups (p < 0.01). The majority of gaseous
microemboli were trapped by the membrane oxygenator. The results of this study
confirm that rotary pump could deliver less gaseous microemboli than roller pump 
at the postpump site when a fixed volume air was introduced into the venous line.
Pulsatile flow could transfer more gaseous microemboli at the postpump site, no
matter which blood pump was used. Only few gaseous microemboli appeared at the
postfilter site at high flow rates with an open arterial filter purge line.

Ann Vasc Surg. 2008 Sep 20. [Epub ahead of print]

Open Surgical Repair of Descending Thoracic Aortic Aneurysms in the Endovascular 
Era: A 9-Year Single-Center Study.

Kieffer E, Chiche L, Cluzel P, Godet G, Koskas F, Bahnini A.

Department of Vascular Surgery.

The purpose of this study was to present a single center's experience with
elective treatment of descending thoracic aortic aneurysms (DTAAs) in the
endovascular era. From July 1997 to May 2005, we operated on 173 patients for
DTAA. A total of 52 patients (30.1%) underwent endovascular stent-graft repair
(group I). Endovascular repair was carried out exclusively in high-surgical risk 
patients in whom preoperative spinal cord arteriography usually demonstrated that
the origin of the Adamkiewicz artery was located outside the zone to be covered
by the stent graft. The remaining 121 patients (69.9%) underwent open surgical
repair (group II), with partial cardiopulmonary bypass in 78 cases (64.5%) and
deep hypothermic circulatory arrest in 43 (35.5%). The two treatment groups
differed significantly with regard to age, prevalence of chronic obstructive
pulmonary disease, number of aneurysms involving the upper segment or full length
of the descending thoracic aorta, and percentage of patients in whom spinal cord 
arteriography was either deemed unnecessary or demonstrated that the origin of
the Adamkiewicz artery was located within the coverage zone. In-hospital
mortality was 15.4% (8/52) in group I vs. 5.0% (6/121) in group II (p = 0.02).
Five deaths after endovascular repair were due to technical causes. All
neurological deficits due to spinal cord ischemia (9/121, 7.4%) including 3.3% of
irreversible flaccid paraplegia occurred in group II (p = 0.04). The findings of 
this study show that open surgical repair achieves excellent results when
high-risk surgical candidates are recommended for endovascular repair. However,
since preoperative spinal cord arteriography was a selection criterion for
endovascular repair, the improvement in mortality was accompanied by a
concentration of spinal cord ischemic complications in the patients having open
surgical repair. The high mortality associated with endovascular repair in our
series should decrease as deployment skill and endovascular technology improve.

J Thorac Cardiovasc Surg. 2008 Sep;136(3):665-72, 672.e1. Epub 2008 Jun 6.

Socioeconomic status and comorbidity as predictors of preoperative quality of
life in cardiac surgery.

Koch CG, Li L, Shishehbor M, Nissen S, Sabik J, Starr NJ, Blackstone EH.

Department of Cardiothoracic Anesthesia, The Cleveland Clinic, Cleveland, Ohio
44195, USA. kochc@ccf.org

OBJECTIVE: Preoperative quality of life of patients undergoing cardiac surgical
procedures has been associated with postoperative morbidity, survival, and
quality of life. Patients of lower socioeconomic status have disproportionately
greater cardiovascular disease burden and more complications of cardiovascular
disease. We examined the interactive effects of demographic characteristics,
socioeconomic status, and comorbidity on preoperative functional quality of life 
measured by the well-validated cardiovascular disease-specific Duke Activity
Status Index. METHODS: The patient population consisted of 5581 patients between 
May 1995 and January 1999 who underwent operations on cardiopulmonary bypass:
isolated coronary artery bypass grafting, isolated valve procedures, or combined 
coronary artery bypass grafting and valve procedures and had a preoperative Duke 
Activity Status Index, along with socioeconomic status information from United
States 2000 census data. Predictors were identified by logistic regression for
maximum value of baseline DASI and linear regression for DASI scores less than
maximum by means of bagging variable selection. RESULTS: Lower socioeconomic
status was associated of lower risk-adjusted quality of life (maximum Duke
Activity Status Index P = .0002, less than maximum Duke Activity Status Index P =
.0007). Older age, female sex, certain comorbidities, higher New York Heart
Association class, lower left ventricular function, and reoperation were also
statistically significantly associated with lower preoperative Duke Activity
Status Index. CONCLUSION: Lower socioeconomic status is associated with lower
risk-adjusted quality of life for patients undergoing cardiac surgery. Quality of
life affects morbid outcomes, so further characterization of risk factors for
poor quality of life offers an opportunity for intervention.

Eur J Cardiothorac Surg. 2008 Sep 6. [Epub ahead of print]

Cognitive outcomes in elderly high-risk patients 1 year after off-pump versus
on-pump coronary artery bypass grafting. A randomized trial.

Jensen BO, Rasmussen LS, Steinbrüchel DA.

Department of Cardio-Thoracic Surgery, The Heart Center, Rigshospitalet,
Copenhagen University Hospital, Copenhagen, Denmark.

Objective: Age is considered to be the strongest predictive factor of
postoperative cognitive dysfunction (POCD) after cardiac surgery. Coronary artery
bypass grafting (CABG) without the use of cardiopulmonary bypass is considered to
be less harmful to the patient, especially in terms of neurological
complications. Methods: The study was a sub-study of the randomized best bypass
surgery trial that compares off-pump to on-pump treatment, with respect to peri- 
and postoperative morbidity in patients with a moderate to high-predicted
preoperative risk. We investigated cognitive outcomes. A total of 120 elderly
patients (mean age 76 years, SD 4.5 years) underwent cognitive testing before
surgery, of which 90 patients (47 vs 43) were available for retesting at 1 year
(mean 370 days) postoperatively, using a neuropsychological test battery that
included seven parameters from four tests. POCD was defined as the occurrence of 
at least two deficits out of the seven possible scores. Secondary analysis was
performed based on definition of 20% decline in cognitive scores compared to
baseline, and using z-score analysis. Results: The incidence of POCD was 19% (95%
CI 9-33) in the off-pump group and 9% (95% CI 3-22) in the on-pump group
(p=0.18). There were no significant differences in the incidence of cognitive
decline between the off-pump and on-pump group regardless of the definition
applied. Conclusions: We were unable to detect that CABG surgery without
cardiopulmonary bypass was associated with significantly better cognitive outcome
in elderly high-risk patients 1 year after the operation.