intraaortic balloon pumping during cardioplegic arrest preserves lung function in patients with...

DOI: 10.1016/j.athoracsur.2006.02.045 2006;82:35-43 Ann Thorac Surg

Pezzo, Pasquale Mastroroberto, Antonio di Virgilio and Attilio Renzulli Francesco Onorati, Lucia Cristodoro, Massimo Bilotta, Barbara Impiombato, Francesco

in Patients With Chronic Obstructive Pulmonary DiseaseIntraaortic Balloon Pumping During Cardioplegic Arrest Preserves Lung Function

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ntraaortic Balloon Pumping During Cardioplegicrrest Preserves Lung Function in Patients Withhronic Obstructive Pulmonary Disease

rancesco Onorati, MD, Lucia Cristodoro, MD, Massimo Bilotta, MD,arbara Impiombato, MD, Francesco Pezzo, MD, Pasquale Mastroroberto, MD,ntonio di Virgilio, MD, and Attilio Renzulli, MD, PhD

ardiac Surgery Unit, Magna Graecia University, Catanzaro, Italy

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Background. Linear flow during cardiopulmonary by-ass is considered a potential mechanism of lung damage

n patients with chronic obstructive pulmonary diseaseCOPD). We evaluated differences in lung function ofatients with COPD undergoing preoperative intraaorticalloon pumping (IABP), between linear flow duringardiopulmonary bypass (IABP-off) and maintenance ofulsatile flow (IABP-on at automatic 80 bpm) duringardioplegic arrest.

Methods. Fifty patients with COPD undergoing preop-rative IABP were randomized between January 2004 anduly 2005 to receive nonpulsatile cardiopulmonary by-ass with IABP discontinued during cardioplegic arrest

25 patients; group A), or IABP-induced pulsatile cardio-ulmonary bypass (25 patients; group B). Hospital out-ome, need for noninvasive ventilation, oxygenationpartial pressure of oxygen, arterial to fraction of inspiredxygen [PaO2/FIO2]), respiratory system compliance, andcoring of chest radiographs were compared.

Results. There were no hospital deaths, no IABP-
elated complications, and no differences in postopera-
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ddress correspondence to Dr Onorati, Viale dei Pini, 28 80131 Napoli,taly; e-mail: [email protected].

2006 by The Society of Thoracic Surgeonsublished by Elsevier Inc

ats.ctsnetjournDownloaded from

ive noninvasive ventilation (group A: 6 of 25, 24.0% vsroup B: 5 of 25, 20%; p � not significant [NS]). Oneatient in both groups developed pneumonia (p � NS).ntensive care and hospital stay were comparable (p �S). Group B showed lower intubation time (8.3 � 5.1ours versus group A: 13.2 � 6.0; p � 0.001), betteraO2/FIO2 at aortic declamping (369.5 � 93.7 mm Hg vs25.7 � 99.3; p � 0.001) at admission in intensive care321.3 � 96.9 vs 246.2 � 109.7; p � 0.003), and at 24 hours349.8 � 100.4 vs 240.8 � 77.3; p � 0.003). The respiratoryystem compliance was better in group B at the end ofurgery (56.4 � 8.2 mL/cm H2O vs 49.4 � 7.0; p � 0.004)nd 8 hours postoperatively (76.4 � 8.2 vs 59.4 � 7.0; p �.0001), as well as scoring of chest radiograph at intensiveare admission (0.20 � 0.41 vs 0.38 � 0.56; p � 0.05) andn the first day (0.26 � 0.45 vs 0.50 � 0.67; p � 0.025).Conclusions. Automatic 80 bpm IABP during car-

ioplegic arrest preserves lung function in patients withOPD.

(Ann Thorac Surg 2006;82:35–43)
© 2006 by The Society of Thoracic Surgeons
he use of cardiopulmonary bypass (CPB) duringcardiac operations is associated with an unspecific

nflammatory reaction that correlates with the occurrencef organ dysfunction and sometimes even serious organailure [1, 2]. Pulmonary dysfunction is a frequent com-lication during the postoperative course of cardiac sur-ery using CPB [3–6]. The severity of such dysfunctionaries from mild alterations in gas exchange, to variousegrees of interstitial pulmonary edema with formationf excessive bronchial secretions, to the acute respiratoryistress syndrome (ARDS) [3–5, 7, 8]. In consequence, up

o 20% of patients undergoing operations with the use ofPB need prolonged ventilation for more than 48 hoursostoperatively [7]. Moreover, clinically manifestedRDS is one of the most common causes of in-hospital

ccepted for publication Feb 17, 2006.

resented at the Poster Session of the Forty-second Annual Meeting ofhe Society of Thoracic Surgeons, Chicago, IL, Jan 30–Feb 1, 2006.

eaths and early and late complications after cardiacurgery [1–8].

Although the mechanisms behind CPB-induced lungnjury are complex (involving the inflammatory reactionaused by the contact of blood with foreign surfaces [5],he type of anesthesia and ventilation [5, 9], the switchrom a pulsatile to a linear flow [10], and the induction ofn ischemia-reperfusion state [5–8]), the observation thataintenance of a finite pulmonary artery blood flow

uring CPB attenuates the degree of the lung injuryuggests that lung ischemia-reperfusion plays a signifi-ant role [11]. Moreover, it has to be kept in mind thaturing CPB the blood flow to the lungs is almost limited

o the bronchial arteries, and it has been proven in sometudies that bronchial artery blood circulation is substan-ially reduced during CPB [11, 12]. Several experimental

odels have shown that the decrease in bronchial arterylood flow during and after warm CPB is the main causef the increased pulmonary vascular permeability withormation of tissue edema and cytokine production, and
evere hypoxemia secondary to intrapulmonary shunt
0003-4975/06/$32.00doi:10.1016/j.athoracsur.2006.02.045

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36 ONORATI ET AL Ann Thorac SurgIABP IMPROVES LUNG FUNCTION IN COPD 2006;82:35–43

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11, 12], which is further associated with metabolic andltrastructural changes of the lung tissue, anticipating

he worsening of CPB-related lung ischemia [7, 12].lthough the nonpulsatile blood flow obtained with

tandard CPB circuits is considered an acceptable, non-hysiologic compromise with few disadvantages (includ-

ng the induction of the systemic inflammatory re-ponse), the theoretical benefits of pulsatile blood flownclude the reduction of vasoconstrictive reflexes, theptimization of oxygen consumption, and the reductionf tissue acidosis, secondary to the improvement of organerfusion [10, 13–16]. Furthermore, we previously dem-nstrated [17] that IABP-induced pulsatile flow duringortic cross-clamp time better preserves splanchnic func-ion in patients without multiorgan comorbidities.

Finally, it is well-known that already damaged lungs,ecause of preoperative chronic obstructive pulmonaryisease (COPD), are at high risk for CPB-induced lungysfunction, so that COPD still represents one of theost common indications to off-pump surgery [10, 18,

9]. In fact, patients with COPD have reduced pulmonaryunction reserve and any injury on their lungs could have

demonstrable clinical effect after CPB [19, 20].Therefore, it was the aim of our study to test the

ypothesis that the maintenance of pulsatile perfusionuring aortic cross-clamp time (ACC), with the aid of

ntraaortic balloon pump (IABP), may attenuate CPB-elated lung damage by improving blood flow throughhe bronchial arteries in the subset of patients at high riskor this complication, such as those with COPD.

aterial and Methods

atients and Study Designetween January 2004 and July 2005, we prospectively

Abbreviations and Acronyms

AMI � acute myocardial infarctionCABG � coronary artery bypass graftingCI � cardiac indexCOPD � chronic obstructive pulmonary

diseaseCPB � cardiopulmonary bypassFEV1 � forced expiratory volume in 1

secondFEV1/FVC � forced expiratory volume in 1

second/forced expiratory vitalcapacity

IABP � intraaortic balloon pumpITU � intensive therapy unitMAP � mean arterial pressurePCWP � pulmonary capillary wedge pressurePVRI � pulmonary vascular resistance indexRSC � respiratory system complianceSCR � scoring of chest radiographsSVRI � systemic vascular resistance indexTnI � troponin I

nrolled 50 patients with COPD undergoing isolated t


rimary CABG for severe left main stem disease. Allatients considered at risk for preoperative ischemicvents because of severe and diffuse coronary lesionscritical left main disease greater than 90%, or severe left

ain lesion greater than 70% with severe right coronarytenosis greater than 75% and unstable angina despitentravenous nitrates) underwent preoperative IABP in-ertion. The study protocol was approved by the Institu-ion’s Ethical Committee-Institutional Review BoardSeptember 2003). Informed consent was obtained fromach patient enrolled in the study.The diagnosis of COPD was based on the Summit

atabase definition: each patient required treatment forhronic pulmonary compromise or had a forced expira-ory volume in 1 second (FEV1) less than 75% of predictedalue or a forced expiratory volume in 1 second to forcedxpiratory vital capacity (FEV1/FVC) less than 0.7. Eachatient underwent a spirometry test and was seen by aneumonologist preoperatively [20].On admission at our Institution, the patients were

andomized by lottery, drawing preprepared sealed en-elopes containing the group assignment. Twenty-fiveatients (group A) received a preoperative IABP treat-ent before induction of anesthesia, with IABP turned off

uring cardioplegic arrest, and restarted with a 1:1 IABPode immediately after cross-clamp removal; the other

5 (group B) received standard preoperative treatmentith IABP, which was switched to an automatic 80 bpmode during cross-clamp time, and switched again to a

:1 IABP mode after cross-clamp removal. In order tovoid misleading data, patients older than 75 years orith splanchnic organ comorbidities (renal or liver fail-re, abdominal aortic aneurysm, or severe autoimmuneisease) were excluded from the study.

nesthesiall patients underwent Swan-Ganz catheter insertion

hrough the right internal jugular vein for continuousemodynamic monitoring before anesthetic induction.ostoperative chest roentgenogram confirmed its exactositioning.Anesthetic technique was the same for all patients:

nduction of anesthesia consisted of intravenous propofolnfusion at 3 mg/kg combined with fentanyl administra-ion at 0.10 mg/kg. Neuromuscular blockade waschieved by 4 mg/hour pancuronium bromide, and lungsere ventilated to normocapnia with air and oxygen

45% to 50%). A positive end-expiratory pressure (PEEP)as set at 5 mm Hg. During CPB, ventilation was discon-

inued but the PEEP was maintained. Propofol infusion150 to 200 �g/kg per minute) and isoflurane (0.5%nspired concentration) maintained anesthesia. Arterialnd central venous catheters were the standard. Ino-ropes were started immediately after aortic cross-clampemoval to maintain adequate mean systemic pressure,lways starting with enoximone at a dosage of 5 �g/kger minute. The need for further increase in inotropesas recorded: inotropic support was defined as low-dosehen enoximone was administered at a dosage lower

han or equal to 5 �g/kg per minute; medium-dose when



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37Ann Thorac Surg ONORATI ET AL2006;82:35–43 IABP IMPROVES LUNG FUNCTION IN COPD

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noximone was employed at a dosage between 6 and 10g/kg per minute, or dobutamine was added at a dosageetween 5 and 10 �g/kg per minute; or high-dose whennoximone or dobutamine infusion was greater than 10g/kg per minute or epinephrine was added at any dose.

urgical Technique and Cardiopulmonary Bypasst was institutional policy to insert IABP (8 Fr, 34 or 40 mLccording to the body surface area; balloon connected to aatascope pump [Datascope Corp, Fairfield, NJ]) percuta-eously, through the best femoral artery, before inductionf anesthesia, in order to better support the perioperativeemodynamic of patients undergoing surgery for severe

eft main stem disease. The correct placement of IABP waslways assessed by postoperative chest roentgenogram orransesophageal echocardiography.

Patients received anticoagulation with enoxaparin,ith a target activated partial thromboplastin time

reater than 40 seconds, starting when the postoperativeleeding was controlled (usually within 6 hours). TheABP was withdrawn when hemodynamic stability wasestored (ie, a cardiac index � 2.0 L/m2 per minute withnly minimal pharmacologic inotropic support, dobut-mine, or enoximone at 5 �g/kg per minute). Cardiopul-onary bypass and surgical techniques were standard-

zed and did not change during the study period.Surgery was performed by the same senior surgeons

AR, PM, AdV) in all cases. In all patients CABG waserformed through a median sternotomy. Cardiopulmo-ary bypass was conducted by the same perfusionist inll cases. Heparin was given at a dose of 300 IU/kg tochieve a target activated clotting time of 480 seconds orbove. Blood recovery with an autotransfusion deviceAutotrans Dideco, Mirandola, Modena, Italy) was per-ormed intraoperatively in all cases. A level of hemoglo-in lower than 8 g/dL suggested blood transfusion. Atandard CPB circuit was used: a Dideco (Mirandola -

odena) tubing set, which included a 40 micron filter, atockert roller pump (Stockert Instrumente, Munich,ermany), and a hollow fiber membrane oxygenator

Monolyth, Sorin Biomedica, Saluggia, Italy). The extra-orporeal circuit was primed with 1000 mL of Ringer’sactate solution and 40 mg of heparin. Systemic temper-ture was kept between 32°C and 34°C. Myocardialrotection was always achieved with intermittent ante-rade and retrograde hyperkalemic blood cardioplegia,s previously reported [21]. The CPB flow was main-ained at 2.6 L · min�1 · m�2. In group A patients, IABPas turned off during cardioplegic arrest, maintaining a

tandard nonpulsatile CPB; group B patients underwentABP-induced pulsatile CPB during cardioplegic arrest:ulsatile flow was maintained by an automatic 80 bpmode until aortic declamping.

ndpointshe primary endpoints were in-hospital mortality andorbidity, perioperative myocardial infarction, in-

ospital and intensive therapy unit (ITU) stay, IABP-elated complications, and investigation of lung function.
n-hospital mortality was defined as any death occurring a

uring hospital stay or in the first 30 postoperative days.ospital morbidity was defined as any complication

equiring specific therapy or causing a delay in hospitalr ITU discharge. Perioperative acute myocardial infarc-ion was defined by new Q waves of greater than 0.04 ms,nd (or) a greater than 25% reduction in R waves in ateast two leads on ECG, by new akinetic or dyskineticegments at echocardiography, with a peak troponin ITnI) greater than 3.7 �g/L or TnI concentration greaterhan 3.1 �g/L at 12 hours postoperatively, as previouslyeported [22]. The IABP-related complications were de-ned as any aortic dissection or perforation, limb oresenteric ischemia, or infection or hemorrhage at the

alloon entry point.Blood samples were obtained from the peripheral

ystemic artery: the neutrophils were counted (Coulterounter SE-9000; Sysmex Corporation, Kobe, Japan), andhe values corrected for the hematocrit values before theperation, at aortic declamping, at the end of surgery,nd on the first and second postoperative days. At theame sampling time-points blood lactate concentrationas measured on a commercial blood gas analyzer (GEMremier 3000 analyzer, Lexington, MA). Determinationsf blood concentration of cardiac TnI were conductedreoperatively before anesthetic induction and at 12, 24,8, and 72 hours postoperatively. In order to evaluate thedequacy of myocardial protection techniques, TnI waseasured on coronary sinus blood samples, obtained

rom the retrograde cardioplegic cannula, 10 minutesfter completion of proximal anastomoses. The TnI as-ays were carried out using diagnostic kits provided byeckman Coulter (Fullerton, California; AccuTnI Access

mmunoassay System).

ung Functionung function was investigated by the following (Table 1).

NTUBATION TIME. Defined as the time interval betweenrotracheal intubation and extubation of the awakeatient.

ATIO OF ARTERIAL OXYGEN TENSION TO INSPIRED OXYGEN FRAC-

ION (pao2/fio2). Arterial blood gas analysis was performedith the samples obtained from the peripheral systemic

rtery (GEM Premier 3000 analyzer, Lexington, MA), andhe Pao2/Fio2 ratio was calculated preoperatively, atortic declamping, at admission in ITU, and at 24 and 48ours.

ESPIRATORY SYSTEM COMPLIANCE (RSC). Expressed in mL/cm2O, the RSC was measured from the mechanical venti-

ator (Evita 4 Drager Medizintechnik GmbH; Lubeck,ermany) preoperatively, at the end of surgery, and at 4

nd 8 hours postoperatively.

CORING OF CHEST RADIOGRAPHS (SCR). Chest roentgenogramas performed preoperatively, at admission in ITU, and

t 24 and 48 hours postoperatively. Scoring of chestadiographs was performed by a blinded radiologist
ccording to the lung injury score, proposed by Murray


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nd colleagues [23], ranging from 0 (no infiltrate) to 4extensive alveolar consolidation).

EED FOR NONINVASIVE VENTILATION (NIV). According to Ferrernd colleagues [24], we decided to start noninvasive posi-ive-pressure ventilation if patients had at least one of theollowing parameters: respiratory acidosis (arterial pH �.35 with partial pressure of carbon dioxide, arterial [Paco2]

45 mm Hg); arterial O2 saturation by pulse-oxymetry lesshan 90% or Pao2 less than 60 mm Hg at inspired O2 fraction.5 or greater; respiratory frequency greater than 35 perinute; decreased consciousness, agitation, or diaphoresis;

linical signs suggestive of respiratory muscle fatigue, andncreased work of breathing such as the use of respiratoryccessory muscles, paradoxical motion of the abdomen, oretraction of the intercostal spaces.

tatistical Analysistatistical analysis was performed by the SPSS program

or Windows, version 10.1 (SPSS Inc, Chicago, IL). Con-inuous variables are presented as mean � SD, andategoric variables are presented as absolute numbersnd (or) percentages. Data were checked for normalityefore statistical analysis.Normally distributed continuous variables were com-

ared using the unpaired t test, whereas the Mann-hitney U test was used for those variables that were not

ormally distributed. Categoric variables were analyzedsing either the �2 test or the Fischer exact test. Compar-

son between and within groups was made using two-ay analysis of variance for repeated measures. Compar-

sons were considered significant if p was less than 0.05.

esults

here were no differences in demographic data between

able 1. Lung Function

PreoperativeAortic

Declamping

ao2/Fio2 (mm Hg) Group A 313.5 � 40.7 225.7 � 99.3Group B 304.8 � 51.8 369.5 � 93.7

pa 0.522 0.001

PreoperativeEnd

Surgery

SC (mL/cm H2O) Group A 79.3 � 9.7 49.4 � 7.0Group B 80.2 � 10.4 56.4 � 8.2

pa 0.436 0.004

Preoperative ITU

CR (Units) Group A 0.01 � 0.001 0.38 � 0.56Group B 0.02 � 0.004 0.20 � 0.41

pa 0.364 0.05

a � statistical probability at each time point; pb � statistical probab

TU � intensive therapy unit; Pao2/Fio2 � partial pressure of oxyompliance; SCR � scoring of chest radiographs.

he two study groups (Table 2). Similarly, intraoperative f


ata were comparable (Table 3). Coronary sinus sam-ling demonstrated a similar leakage of TnI (group A:.70 � 0.34 �g/L vs group B: 0.61 � 0.48 �g/L; p � 0.095),howing a comparable myocardial protection during aor-ic cross-clamping. Similarly, perioperative hemody-amic data were comparable between the two groups

Table 4).There were no hospital deaths or perioperative myo-

ardial infarctions in either group. Again, postoperativenI course was similar between the two groups (Fig.1A).As far as inotropic support was concerned, all but 3

atients were withdrawn from low-dose enoximone onhe third postoperative day: 2 patients in group A re-uired medium doses of enoximone (7.5 �g/kg perinute), starting intraoperatively until the third and the

ourth postoperative days, respectively; one patient inroup B required medium doses of inotropes because of

ntraoperative association with low-dose intravenous (IV)obutamine due to a cumbersome weaning from CPB.Mean in-ITU stay (group A: 2.3 � 0.5 days versus group

: 2.1 � 0.9; p � 0.880) and mean postoperative hospital staygroup A: 7.5 � 1.1 days versus group B: 6.9 � 1.6; p � 0.176)ere similar between the two groups. There were no majorr minor IABP-related complications in either group.There were six postoperative complications among the

ntire study period. One patient in group A (4%; p �.500) developed perioperative ileus requiring rehydra-ion and IV fenoldopam; 1 patient in each group (4%; p �.755) experienced lung pneumonia requiring NIV andral antibiotics; 2 patients (8%) in group A and 1 patient4%; p � 0.500) in group B developed postoperative atrialbrillation requiring IV amiodarone. However, all pa-

ients recovered during hospital stay and were dis-harged home in sinus rhythm and in healthy condition.

As far as lung function was considered we found the

ITU 24 h 48 h pb pc

46.2 � 109.7 240.8 � 77.3 289.9 � 77.7 0.0221.3 � 96.9 349.8 � 100.4 347.5 � 89.1 0.03 0.011

0.003 0.003 0.433

4 h 8 h pb pc

52.7 � 11.2 59.4 � 7.0 0.04573.1 � 13.1 76.4 � 8.2 0.08 0.001

0.0001 0.0001

24 h 48 h pb pc

0.50 � 0.67 0.34 � 0.03 0.0010.26 � 0.45 0.28 � 0.05 0.015 0.03

0.025 0.078

ithin-group; pc � statistical probability between-group.

arterial to fraction of inspired oxygen; RSC � respiratory system

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NTUBATION TIME. Group B showed lower intubation time8.3 � 5 .1 hours versus group A: 13.2 � 6.0; p � 0.001).

ao2/Fio2 RATIO. The Pao2/Fio2 ratio proved to be better inroup B at aortic declamping, at admission in ITU, and at4 hours (Table 1). It is noteworthy, the different behaviorf the Pao2/Fio2 ratio in the two groups: patients under-oing standard CPB with linear flow during ACC dem-nstrated a gradual decrease of oxygenation during thentire surgical period, showing a gradual increase in theate postoperative time and reaching the pre-CPB valuesnly on the second postoperative day. On the other side,he ratio demonstrated an early amelioration at aorticeclamping in patients undergoing automatic IABP dur-

ng ACC, and maintaining a better, or at least the same,alue than that of the preoperative time during the entireostoperative course.

SC. Respiratory system compliance worsened in bothroups after CPB, with a slow but progressive improve-ent in the first few hours after surgery. Again, patients

ndergoing pulsatile CPB during ACC showed betteralues of RSC at the end of surgery, and a greatermprovement either at 4 and 8 hours postoperativelyTable 1).

able 2. Patient Demographics and Characteristics

Group

ean age 69.ex (M/F)uroscore 5.iabetes 13ypertension 16nstable angina 21cute myocardial infarction �4 weeks 16all motion score index (mean) 1.6

reoperative ejection fraction 39.ndexed left ventricular mass �125 g/m2 15ao2% 92.EV1 60.EV1/FVC 63.

EV1 � forced expiratory volume in 1 second; FVC � forced expirato

able 3. Intraoperative Data

Group A

ortic cross-clamp time 42.7ardiopulmonary bypass time 78.9erfusion pressure (mm Hg) (mean) 60.5umber of grafts 3.9omplete arterial revascularization 5 (

ntraoperative defibrillation 1 (notropes, low-dose 23 (notropes, medium-dose 2 (notropes, high-dose
ransfusion of packed red blood cells 8 (32%)

CR. We registered a slight worsening of chest radio-raphs in both groups during the postoperative course;owever, patients belonging to group B demonstratedetter SCR compared with groupA, either at ITU admis-ion or on the first postoperative day (Table 1).

EED FOR NIV. No differences were found in postoperativeIV (group A: 6 of 25, 24.0% vs group B: 5 of 25, 20%; p �S).As far as perioperative hemochrome was considered,

eutrophils proved to be lower in group B at aorticeclamping, at the end of surgery, and on the firstostoperative day, as shown in Figure 1B. Finally, periph-ral blood lactate proved to be lower in group B at theame time-points (Fig 1C).

omment

ince the early days of cardiac surgery, it has beenecognized that CPB is associated with systemic inflam-ation, and that occasionally this leads to major organ

ysfunction [6]. In particular, pulmonary dysfunctionfter CPB was first described 40 years ago [25]. Manytudies have focused on the pathophysiologic mecha-

� 25) Group B (n � 25) p

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.2 37.8 � 6.7 0.681) 15 (60%) 0.538

.8 91.7 � 3.2 0.369

.9 62.0 � 5.4 0.645

.2 64.1 � 7.7 0.440

al capacity; Sao2 � oxygen saturation, arterial.

25) Group B (n � 25) p

8 53.6 � 21.3 0.1218 82.2 � 19.6 0.2577 64.1 � 16.4 0.099

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isms of CPB-induced lung injury, involving the systemicnflammatory response through the contact of blood withhe artificial surfaces of the bypass circuit [5], the type ofnesthesia and artificial ventilation [5, 9], the switch fromphysiologic pulsatile flow to an artificial linear flow [10],nd the induction of an ischemia-reperfusion state of theung [5–8]. In particular, during CPB both the heart andhe lungs are excluded from the circulation: while the

yocardium is generally protected by cardioplegia, noeasures are taken to protect the lung [26]. Moreover, of

he two circulatory systems of the lungs, the blood isimited to flowing to the lungs during CPB almost alwayshrough the bronchial arteries [7, 10, 26]. Finally, if underormal conditions the predominant function of the bron-hial circulation is to nourish the nonalveolar lung tissues27], when the pulmonary blood flow seizes bronchiallood flow may be expected to increase as a compensa-

ory measure [28]. However, Schlensak and colleagues26] demonstrated that although CPB reduced pulmo-ary artery blood flow, it did not increase the bronchialow to the lungs, adding another mechanism of ischemic

njury to the lungs. On the other side, Kuratani andolleagues [29] demonstrated that during partial CPB theungs are perfused mainly by the bronchial arteries, andhat the regional blood flow to the lungs decreased to0% of the pre-bypass values. Moreover, there are someata showing that the maintenance of a finite pulmonaryrtery blood flow during CPB attenuates the degree ofhe lung injury, suggesting the critical role of an isch-mia-reperfusion mechanism on the pathophysiology ofostoperative pulmonary dysfunction [11].Patients with COPD have an increased risk of organ-

ailure morbidity after cardiac surgery [30]. Bevelaqua

able 4. Hemodynamic Data

Pre-CPB

AP (mm Hg) Group A 73.1 � 13.4Group B 70.6 � 10.8

pa 0.197I (L/min m2) Group A 2.21 � 0.57

Group B 2.13 � 0.38pa 0.661

CWP (mm Hg) Group A 12.2 � 4.1Group B 12.9 � 8.8

pa 0.369VRI

dyne s cm�5 m�2)Group A 2502 � 565

Group B 2456 � 612pa 0.660

VRIdyne s cm�5 m�2)

Group A 291 � 45

Group B 272 � 83pa 0.487

a � statistical probability at each time point; pb � statistical probab

PB � cardiopulmonary bypass; CI � cardiac index; ITU � intenapillary wedge pressure; PVRI � pulmonary vascular resistance ind

Post-CPB ITU 1st day pb pc

66.8 � 13.0 69.2 � 11.5 75.7 � 12.8 0.704 0.20270.5 � 15.7 72.4 � 18.4 76.0 � 11.6 0.115

0.079 0.141 0.5071.52 � 0.84 2.10 � 0.91 2.98 � 0.99 0.538 0.1171.55 � 0.62 2.23 � 1.02 2.95 � 0.77 0.645

0.480 0.111 0.76116.5 � 2.9 16.1 � 2.4 12.3 � 7.2 0.098 0.26614.9 � 4.0 15.5 � 5.0 13.0 � 6.6 0.588

0.091 0.618 0.3953072 � 518 2555 � 298 2492 � 252 0.257 0.704

2966 � 622 2601 � 446 2338 � 312 0.1490.681 0.699 0.440

405 � 150 326 � 68 220 � 33 0.163 0.052

349 � 88 255 � 97 189 � 48 0.3690.055 0.060 0.156

ility within-group; pc � statistical probability between-group.

nd colleagues [31] demonstrated that although nonpul- p


ig 1. Troponin I (A), peripheral blood neutrophils (B), and periph-ral blood lactate (C) measurements by group (� � group A; � �roup B) at different time points. (pa � statistical probability at eachime point; pb � statistical probability within-group; pc � statistical
robability between-group; ITU � intensive therapy unit.)


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atile CPB is used more extensively than pulsatile CPB, itauses a more pronounced pulmonary dysfunction inatients with preoperative COPD. Therefore, although

he nonpulsatile blood flow obtained with standard CPBircuits is considered an acceptable nonphysiologic com-romise with few disadvantages, first of all the inductionf the inflammatory response, the theoretical benefits ofulsatile blood flow include the reduction of vasocontric-

ive reflexes, the optimization of oxygen consumption,nd the reduction of acidosis, secondary to the improve-ent of organ perfusion [10, 13–16]. According to these

ndings, because of the avoidance of blood contact withoreign surfaces and the maintenance of a physiologiculsatile perfusion, a recent study by Staton and col-

eagues [19] has shown off-pump surgery to achieveetter gas exchange and earlier extubation than on-pumpurgery in patients with COPD.

Therefore, it seems that a pulsatile perfusion and anugmentation of lung perfusion through the collateralronchial arteries can ameliorate functional results inatients with COPD undergoing on-pump surgery. Weypothesized that this goal could be achieved with theid of IABP, switching it to an automatic 80 bpm modeuring aortic cross-clamping. In fact, it is common prac-

ice to discontinue IABP during cardioplegic arrest be-ause of the loss of ECG signal, although switching it ton automatic mode a pulsatile flow could be achieved.

e have evaluated this aspect of perioperative supportith IABP.When pulmonary outcome is considered, we found

etter functional results in patients belonging to group B,ither in terms of intubation time, Pao2/Fio2 ratio, RSC,r SCR. It is noteworthy that differences were found to beignificant at very early time-points, such as aorticeclamping (Pao2/Fio2 ratio), at the end of surgery (RSC),t admission in ITU (Pao2/Fio2 ratio, SCR), during therst few postoperative hours (RSC), and on the firstostoperative day (Pao2/Fio2 ratio, SCR). Our data cor-elated with those of Tarcan and colleagues [10], whoound in patients with COPD undergoing pulsatile CPBwith the aid of a second roller pump integrated in thePB circuit) shorter intubation time, lower pulmonaryascular resistance, and lower neutrophil count. Simi-arly, an increase in alveolar septal thickening, a de-reased alveolar surface area, and a reduced capacity toxygenate blood associated with a CPB-induced reduc-ion of bronchial blood flow [26] have been demon-trated. Kuratani and colleagues [29] demonstrated thatulmonary dysfunction and the derangement of theltrastructural lung tissue after CPB were less severemong the patients whose bronchial blood flow exceeded5% of the systemic blood flow. Another experimentalork by Serraf and colleagues [32] showed that a pulmo-ary blood flow of 35 mL/kg per minute obviated the

ung injury. Although these studies failed to clarify theptimal flow rate of the bronchial arterial system duringPB, it is likely that more than normal bronchial bloodow is the prerequisite for protection of the lung duringPB [33]. According to this, it is well-known that one of

he main goals achieved by IABP is the amelioration of s


rgan perfusion by an augmentation of the blood flow34]. Therefore, we can hypothesize that automatic IABP

ode during ACC improves bronchial blood flow, fur-hermore maintaining somewhat pulsatile perfusion, re-ucing the ischemic-reperfusion mechanism of CPB-

nduced lung injury. According to a limited ischemicnjury, we found lower lactate levels from aorticeclamping to the first postoperative day in patientsndergoing pulsatile perfusion during ACC. These dataay correlate with the recent evidence of higher lung-

issue lactate production parallel to the reduction ofronchial blood flow during CPB [26]. Moreover, it haseen demonstrated that the augmentation of bronchialow improves the lung lymph flow, which clears excessf lung fluid, especially in cases of lung inflammatoryesponse [35]. In this way we can interpret our findings ofetter RSC in patients belonging to group B.Except for a shorter intubation time, we did not find

ignificant differences in hospital outcome or in terms ofajor lung complications such as pneumonia and need

or NIV. Similarly, we found comparable hospital staynd ITU stay between the two groups. It is possible thathe short difference in the time course of linear versusulsatile flow (ie, the duration of the aortic cross-clamp

ime, at present ranging from about 20 to 60 minutes) didot account for a significantly impaired organ perfusion

n patients in whom IABP was turned off during car-ioplegic arrest. It can be hypothesized that partial CPB

as in CABG) did not account for a severe impairment ofronchial perfusion, as in total CPB, in which it has beenhown that bronchial blood flow decreased to 11% of there-bypass value [29]: this would indicate that partialPB attenuates the degree of the ischemic-reperfusion

ung injury, limiting therefore the incidence of majoromplications.

Finally, we found a significant lower neutrophil countn the peripheral blood of patients belonging to group B.ardiopulmonary bypass-induced lung damage is medi-ted by neutrophil activation, which infiltrated the alveoliuring the ischemia-reperfusion period [36], and can beasily detected in the bronchial lavage fluid after CPB12]. Suzuki and colleagues [34] demonstrated that theeutrophil sequestration in the lung was less severe inatients undergoing pulmonary perfusion during CPB;imilarly, Schlensak and colleagues [12] found a signifi-ant accumulation of neutrophils in bronchoalveolar la-age of piglets undergoing CPB, parallel to the reductionf the bronchial perfusion. Our data also confirm those ofarcan and colleagues [10], who demonstrated a lowerhite cell count together with a higher percentage ofeutrophils in the peripheral blood of COPD patientsndergoing nonpulsatile CPB. It may be argued that an

ABP-induced pulsatile perfusion during ACC, togetherith an improvement of blood flow through the bron-

hial arteries, may attenuate the neutrophil-related CPB-nduced lung injury.

imitationshe main limitation of the study is related to the small
ample size of patients enrolled in the study.


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This is a result of the single-center design of the studytself, which, on the other hand, guarantees uniformity ofhe perioperative management of the patient populationhroughout the experimentation. Moreover, on an inten-ion-to-treat basis, we enrolled patients with the mostimilar risk profile, as patients with severe coronaryesions, without severe organ comorbidities other thanOPD or extensive extracardiac atherosclerosis, whichay mislead the results. Finally, patients were operated

n by the same senior surgeons and underwent the samePB, led by the same perfusionist, thus reducing the riskf human bias. However, the small sample size of theopulation remains, as well as the small incidence ofome major complications (mortality, IABP-related com-lications, etc), which failed to demonstrate differencesther than lung function in some of the establishedrimary endpoints.

onclusionse conclude that although automatic 80 bpm IABP

uring cardioplegic arrest does not influence majorlinical outcomes, it significantly preserves lung func-ion in COPD patients undergoing CABG. These dif-erences are already evident even for cross-clamp timeower than 60 minutes. Consequently, there is noeason, in COPD patients undergoing preoperativeABP support, to turn off the pump during cardioplegicrrest, but our data suggest that a switch to theutomatic mode is ideal.

eferences

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5. Jacobs LA, Klopp EH, Seamone W, Topaz SR, Gott VL.Improved organ function during cardiac bypass with a rollerpump modified to deliver pulsatile flow. J Thorac CardiovascSurg 1969;58:703–12.

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0. Higgins TL, Estefanous FG, Loop FD, Beck GJ, Blum JM,Paranandi L. Stratification of morbidity and mortality out-come by preoperative risk factors in coronary artery bypasspatients: a clinical severity score. JAMA 1992;267:2344–8.

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2. Serraf A, Robotin M, Bonnet N, et al. Alteration of theneonatal pulmonary physiology after total cardiopulmonary

ertification in 2006

ion for recertification. This practice review should con-

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2006 by The Society of Thoracic Surgeonsublished by Elsevier Inc


3. Christenson JT, Simonet F, Badel P, Schmuziger M. Optimaltiming of preoperative intraaortic balloon pump support inhigh-risk coronary patients. Ann Thorac Surg 1999;68:934–9.

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5. Wagner EM, Blosser S, Mitzner W. Bronchial vascular con-tribution to lung lymph flow. J Appl Physiol 1998;85:2190–5.

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equirements for Recertification/Maintenance of

iplomates of the American Board of Thoracic Surgeryho plan to participate in the Recertification/aintenance of Certification process in 2006 must hold

n active medical license and must hold clinical privi-eges in thoracic surgery. In addition, a valid certificate isn absolute requirement for entrance into the recertifi-ation/maintenance of certification process. if your cer-ificate has expired, the only pathway for renewal of aertificate is to take and pass the Part I (written) and theart II (oral) certifying examinations.The American Board of Thoracic Surgery will no longer

ublish the names of individuals who have not recerti-ed in the American Board of Medical Specialties direc-

ories. The Diplomate’s name will be published uponuccessful completion of the recertification/maintenancef certification process.The CME requirements are 70 Category I credits in

ither cardiothoracic surgery or general surgery earneduring the 2 years prior to application. SESATS andESAPS are the only self-instructional materials allowed

or credit. Category II credits are not allowed. The Phy-icians Recognition Award for recertifying in generalurgery is not allowed in fulfillment of the CME require-ents. Interested individuals should refer to the Booklet

f Information for a complete description of acceptableME credits.Diplomates should maintain a documented list of theirajor cases performed during the year prior to applica-

ist of 1 year’s consecutive major operative experiences.f more than 100 cases occur in 1 year, only 100 should beisted.

Candidates for recertification/maintenance of certifica-ion will be required to complete all sections of theESATS self-assessment examination. It is not necessary

or candidates to purchase SESATS individually becauset will be sent to candidates after their application haseen approved.Diplomates may recertify the year their certificate

xpires, or if they wish to do so, they may recertify up towo years before it expires. However, the new certificateill be dated 10 years from the date of expiration of theirriginal certificate or most recent recertification certifi-ate. In other words, recertifying early does not alter the0-year validation.Recertification/maintenance of certification is also

pen to Diplomates with an unlimited certificate and willn no way affect the validity of their original certificate.

The deadline for submission of applications for theecertification/maintenance of certification process is

ay 10 each year. A brochure outlining the rules andequirements for recertification/maintenance of certifica-ion in thoracic surgery is available upon request fromhe American Board of Thoracic Surgery, 633 N St. Clairt, Suite 2320, Chicago, IL 60611; telephone: (312)02-5900; fax: (312) 202-5960; e-mail: [email protected]. This
ooklet is also published on the website: www.abts.org.
Ann Thorac Surg 2006;82:43 • 0003-4975/06/$32.00



DOI: 10.1016/j.athoracsur.2006.02.045 2006;82:35-43 Ann Thorac Surg

Pezzo, Pasquale Mastroroberto, Antonio di Virgilio and Attilio Renzulli Francesco Onorati, Lucia Cristodoro, Massimo Bilotta, Barbara Impiombato, Francesco

in Patients With Chronic Obstructive Pulmonary DiseaseIntraaortic Balloon Pumping During Cardioplegic Arrest Preserves Lung Function

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