Adult cardiac surgery outcomes: role of the pump type

Transcription

1 Europen Journl of Crdio-thorcic Surgery 18 (2000) 575±582 Adult crdic surgery outcomes: role of the pump type A. Prolri*, F. Almnni, M. Nlito, R. Spirito, V. FrnzeÁ, G. Pompilio, M. Agrifoglio, P. Biglioli Deprtment of Crdic Surgery, University of Miln, Centro Crdiologico, Fondzione I Monzino IRCCS, Vi Pre 4, Miln, Itly Received 13 June 2000; received in revised form 1 August 2000; ccepted 17 August 2000 Abstrct Objective: This study ws crried out to evlute whether the type of pump used for crdiopulmonry bypss (CPB; roller vs. centrifugl) cn ffect mortlity or the neurologicl outcomes of dult crdic surgery ptients. Methods: Between 1994 nd June 1999, 4000 consecutive ptients underwent coronry nd/or vlve surgery t our hospitl; of these, 2213 (55.3%) underwent surgery with centrifugl pump use, while 1787 (44.7%) were operted on with roller pump. The effect of the type of the pump nd of 36 preopertive nd intropertive risk fctors for periopertive deth, permnent neurologicl de cit nd com were ssessed using univrite nd multivrite nlyses. Results: The overll in-hospitl mortlity rte ws 2.2% (88/4000), permnent neurologicl de cit occurred in 2.0% (81/4000) of ptients, nd com in 1.3% (52/4000). There ws no difference in hospitl mortlity between ptients operted with the use of centrifugl pumps nd those operted with roller pumps (50/2213 (2.3%) vs. 38/1787 (2.1%); P ˆ 0:86). On the other hnd, ptients who underwent surgery with centrifugl pumps hd lower permnent neurologicl de cit (34/2213, (1.5%) vs. 47/1787 (2.6%); P ˆ 0:020) nd com (20/2213 (0.9%) vs. 32/1787 (1.8%); P ˆ 0:020) rtes thn ptients operted with roller pumps. Multivrite nlysis showed CPB time, previous TIA nd ge s risk fctors for permnent neurologicl de cit, while centrifugl pump use emerged s protective. Multivrite risk fctors for com were CPB time, previous vsculr surgery nd ge, while centrifugl pump use ws protective. Conclusions: Centrifugl pump use is ssocited with reduced rte of mjor neurologicl complictions in dult crdic surgery, lthough this is not prlleled by decrese in in-hospitl mortlity. q 2000 Elsevier Science B.V. All rights reserved. Keywords: Roller pump; Centrifugl pump; Mortlity; Neurologicl outcome 1. Introduction Neurologicl injury is one of the most debilitting complictions fter dult crdic surgery performed using crdiopulmonry bypss (CPB). Despite continuous trend towrds decline in overll mortlity in dult crdic surgery, n increse in the verge ge of ptients undergoing crdic surgery hs resulted in substntil increse in serious dverse neurologicl events, nd in the proportion of relted in-hospitl deths[1,2]. Previous studies hve ssessed the effect of CPB on neurologicl outcomes in dult ptients undergoing crdic surgery[3±10]; however, little informtion exists on whether the type of the pump used for CPB (roller vs. centrifugl) cn ffect the neurologicl outcomes of dult ptients undergoing crdic surgery. * Corresponding uthor. Tel.: ; fx: E-mil ddress: prolri@crdiologicomonzino.it (A. Prolri). The im of this study ws to evlute risk fctors for periopertive mortlity nd dverse neurologicl outcomes, with specil emphsis on the role of using roller or centrifugl pump for perfusion. 2. Ptients nd methods We hve retrospectively reviewed the chrts of 4000 consecutive ptients who, during the period of Jnury 1994±June 1999, underwent coronry nd/or vlve surgery with the use of CPB t our hospitl. Ptients who hd dditionl procedures performed (LV neurysmectomy, crotid endrterectomy, scending ort replcement) were excluded from the study Surgicl procedure On the morning of surgery, ptients received their usul dose of ntinginl drugs, nd 2±5 mg morphine nd 1 mg tropine s premediction. All ptients received stndrd moderte dose of fentnyl nd benzodizepine nesthesi, /00/$ - see front mtter q 2000 Elsevier Science B.V. All rights reserved. PII: S (00)

2 576 A. Prolri et l. / Europen Journl of Crdio-thorcic Surgery 18 (2000) 575±582 which ws induced by the dministrtion of sodium thiopentl (3 mg/kg), fentnyl (0.75 mg/kg), succinylcholine (1 mg/kg), dizepm (10 mg) nd pncuronium bromide (0.1 mg/kg). After endotrchel intubtion, ptients were ventilted to normocpni with n oxygen nd ir mixture. Boluses of fentnyl (with or without droperidol), dizepm nd pncuronium bromide were given when necessry. Cefuroxime (2 g) ws given intrvenously for infection prophylxis. A rdil rtery ctheter nd ow-directed pulmonry rtery ctheter were inserted for hemodynmic mesurements. The extrcorporel circuit consisted of roller pump (CAPS HLM; Stockert Instruments, Munich, Germny) or centrifugl pump (Biomedicus BioPump; Medtronic, Miln, Itly), hollow ber oxygentor with integrted het exchnger, rteril lter, crdiotomy reservoir nd polyvinyl tubing system. In ll cses, n `open' system ws used for perfusion. The type of pump ws chosen bsed on consensus between the surgeon nd nesthesiologist, with preference given to the centrifugl pump for CPB times which were expected to be longer (.100 min). No heprin bonding ws used in the perfusion tubing or oxygentor. The extrcorporel circuit ws primed with 1500 ml electrolyte solution nd 5000 IU bovine lung heprin (Liquemin; Roche, Itly). After systemic hepriniztion (300 U/kg), CPB ws initited with cnnuls plced in the scending ort nd right trium. The ctivted clotting time ws kept t $400 s with dditionl heprin. The pump ow ws non-pulstile in ll opertions. The ow rte ws mintined t 2.4 l/min per m 2 during cooling Tble 1 Preopertive vribles of the study popultion Age t intervention (yers) 64 (57±70) Preopertive weight (kg) 76 (64±80) Body surfce re (m 2 ) 1.8 (1.7±1.9) Mle sex 2885/4000 (72) History of hypertension 2142/4000 (54) History of smoking 1610/4000 (40) Previous myocrdil infrction 1685/4000 (42) Previous crdic surgery 288/4000 (7.2) Previous vsculr surgery 152/4000 (3.8) Insulin-dependent dibetes mellitus 103/4000 (2.6) Peripherl vsculr disese 414/4000 (10) History of sthm 66/4000 (1.7) History of COPD 344/4000 (8.6) History of hert filure 535/4000 (13) Previous TIA 271/4000 (6.8) Previous RIND 43/4000 (1.1) Previous stroke 147/4000 (3.7) Previous neurologicl events 448/4000 (11) Blood hemtocrit (%) 39 (36±42) Blood cretinine level (mg/dl) 1.1 (9±1.2) Blood cretinine level (.2 mg/dl) 57/4000 (1.4) Sinus rhythm t preopertive EKG 3380/4000 (85) Numbers in prentheses represent either percentge vlues or 25th nd 75th percentiles. nd rewrming phses, nd t 2.0 l/min per m 2 during stble hypothermi. The men rteril pressure (MAP) during CPB ws mintined between 60 nd 90 mmhg, with CPB ows set s previously described, nd vsoctive drugs were used to mintin the MAP in the desired rnge: if the MAP incresed bove the desired rnge, nd ws unresponsive to fentnyl or dizepm, sodium nitroporusside ws strted, but if the MAP fell below the desired rnge, norepinephrine, boluses or continuous infusion were dded. Ptients were cooled to 28±308C. CPB ows nd pressures were downloded from the monitor nd recorded every 5 min during perfusion. Any signi cnt modi ction of the perfusion pttern during 5 min time intervls ws lso recorded by the perfusionist. For myocrdil protection, ptients received rst dose (1000 cc) of cool (48C) ntegrde nd retrogrde high-potssium cold crystlloid crdioplegi (St. Thoms Hospitl Crdioplegic solution contining 110 mmol/l NCl, 16 mmol/l KCl, 16 mmol/l MgCl 2, 1.2 mmol/l CCl 2 nd 10 mmol/l NHCO 3 ) just fter ortic cross-clmping, which ws repeted (250 ml retrogrde) t every 20 min of the ortic cross-clmp time. Disturbnces in the cid±bse blnce were ppropritely treted, nd the cid±bse equilibrium ws mintined by the lph-stat method. The hemtocrit during CPB ws mintined t 18±25%. After termintion of CPB, heprin ws ntgonized with protmine sulfte t 1:1 rtio (3 mg/kg). If necessry, inotropic support ws given when ptients were wened from CPB. Autologous blood nd residul volume from the extrcorporel circuit were infused into the ptient when volume supplementtion ws necessry. Tble 2 Opertive vribles of the study popultion Type of surgery CABG 2704/4000 (68) AVR 477/4000 (12) MVR 416/4000 (10) DVR 220/4000 (5.5) CABG 1 VR 183/4000 (4.5) Use of centrifugl pump for CPB 2213/4000 (55) Aortic cross-clmp time (min) 79 (61±101) CPB time (min) 109 (88±136) Need to perform circultory rrest (.5 min) 17/4000 (0.4) CPB ow during the cooling phse (l/min per m 2 ) 2.3 (2.1±2.4) Blood pressure during the cooling phse (mmhg) 70 (60±80) CPB ow during the stble hypothermi phse 2 (1.8±2.2) (l/min per m 2 ) Blood pressure during the stble hypothermi phse 75 (65±85) (mmhg) CPB ow during the rewrming phse (l/min per m 2 ) 2.3 (2.2±2.4) Blood pressure during the rewrming phse (mmhg) 70 (65±80) Minimum esophgel temperture reched (8C) 29.2 (27.6±30.0) Minimum rectl temperture reched (8C) 30.6 (29.6±31.5) CPB ow during the entire bypss time 2.2 (2.1±2.3) (l/min per m 2 ) Blood pressure during the entire bypss time (mmhg) 73 (67±79) Numbers in prentheses represent either percentge vlues or 25th nd 75th percentiles.

3 Tble 3 Preopertive vribles of the study popultion by the type of pump A. Prolri et l. / Europen Journl of Crdio-thorcic Surgery 18 (2000) 575± Vrible Centrifugl pump Roller pump P Age t intervention (yers) 64 (57±70) 64 (56±70) 0.25 Preopertive weight (kg) 72 (64±80) 71 (64±80) Body surfce re (m 2 ) 1.8 (1.7±1.9) 1.8 (1.7±1.9) 0.25 Mle sex b 73 (1614/2213) 71 (1271/1787) 0.21 History of hypertension b 53 (1176/2213) 54 (966/1787) 0.58 History of smoking b 41 (915/2213) 39 (695/1787) 0.12 Previous myocrdil infrction b 45 (984/2213) 39 (701/1787), Previous crdic surgery b 8.6 (190/2213) 5.5 (98/1787), Previous vsculr surgery b 3.7 (81/2213) 4.0 (71/1787) 0.66 Insulin-dependent dibetes mellitus b 3.1 (68/2213) 2.0 (35/1787) Peripherl vsculr disese b 11 (239/2213) 9.8 (175/1787) 0.32 History of sthm b 1.7 (37/2213) 1.6 (29/1787) 0.99 History of COPD b 8.2 (181/2213) 9.1 (163/1787) 0.31 History of hert filure b 12 (275/2213) 15 (260/1787) Previous TIA b 7.7 (170/2213) 5.7 (101/1787) Previous RIND b 1.1 (25/2213) 1.0 (18/1787) 0.82 Previous stroke b 4.2 (94/2213) 3.0 (53/1787) Previous neurologicl events b 13 (285/2213) 9.1 (163/1787), Blood hemtocrit (%) 40 (36±43) 39 (35±42), Blood cretinine level (mg/dl) 1.1 (0.9±1.2) 1.1 (0.9±1.2) 0.23 Blood cretinine level (.2 mg/dl) b 1.5 (33/2213) 1.3 (24/1787) 0.78 Sinus rhythm t preopertive EKG b 84 (1859/2213) 85 (1521/1787) 0.35 b Centrifugl vs. roller. Figures represent either percentge vlues followed by the proportion in prentheses or medin followed by 25th nd 75th percentile in prentheses. After surgery, ptients were dmitted to the intensive cre unit (ICU) nd treted ccording to stndrdized protocol. The MAP ws kept t 70±90 mmhg, hert rte t 70±90 bets/min, nd the crdic index ws mintined t greter thn 2.0 l/min per m 2. Inotropic support ws dministered when necessry. Ptients were ventilted to normocpni, nd n rteril oxygen tension of 80 mmhg with continuous positive-pressure ventiltion until extubtion ws mintined ccording to the ICU regimen. Bsic uid dministrtion consisted of 0.9% NCl nd polygeltine. Pcked erythrocytes were infused when the hemtocrit ws,18% during CPB nd,24% in the ICU. When their crdio- Tble 4 Opertive vribles of the study popultion by the type of pump Vrible Centrifugl pump Roller pump P Type of surgery CABG b 68 (1513/2213) 67 (1191/1787) 0.30 AVR b 12 (264/2213) 12 (213/1787) MVR b 11 (232/2213) 10 (184/1787) DVR b 5 (107/2213) 6 (113/1787) CABG 1 VR b 4 (97/2213) 5 (86/1787) Aortic cross-clmp time (min) 81 (62±1049) 76 (60±98), CPB time (min) 112 (90±140) 106 (85±131), Need to perform circultory rrest (.5 min) b 0.7 (16/2213) 0.4 (7/1787) 0.24 CPB ow during the cooling phse (l/min) 2.3 (2.2±2.4) 2.3 (2.2±2.4), Blood pressure during the cooling phse (mmhg) 75 (65±80) 70 (60±75), CPB ow during the stble hypothermi phse (l/min per m 2 ) 2.0 (1.8±2.1) 2.0 (1.8±2.2), Blood pressure during the stble hypothermi phse (mmhg) 80 (70±85) 70 (60±80), CPB ow during the rewrming phse (l/min per m 2 ) 2.3 (2.2±2.4) 2.3 (2.2±2.5), Blood pressure during the rewrming phse (mmhg) 75 (65±80) 70 (65±75), Minimum esophgel temperture reched (8C) 29.5 (28.5±30.1) 28.3 (27.1±29.8), Minimum rectl temperture reched (8C) 30.8 (30.0±31.6) 30.4 (29.3±31.5), CPB ow during the entire bypss time (l/min per m 2 ) 2.2 (2.0±2.3) 2.2 (2.1±2.4), Blood pressure during the entire bypss time (mmhg) 75 (69±82) 70 (63±77), b Centrifugl vs. roller. Figures represent either percentge vlues followed by the proportion in prentheses or medin followed by 25th nd 75th percentile in prentheses.

4 578 A. Prolri et l. / Europen Journl of Crdio-thorcic Surgery 18 (2000) 575±582 Tble 5 Signi cnt or borderline univrite risk fctors for in-hospitl deth Vrible In-hospitl deths vs. hospitl survivors P vlue Age t intervention (yers) 67 (61±71) vs. 64 (57±70) Preopertive weight (kg) 65 (55±76) vs. 72 (64±80), Body surfce re (m 2 ) 1.7 (1.6±1.9) vs. 1.8 (1.7±1.9) Mle sex 61 (54/88) vs. 72 (2831/3912) Previous crdic surgery 22 (19/88) vs. 6.9 (269/3912), History of COPD 17 (15/88) vs. 8.4 (329/3912) History of hert filure 24 (21/88) vs. 13 (514/3912) Previous RIND 3.4 (3/88) vs. 1.0 (40/3912) 0.1 Previous stroke 8.0 (7/88) vs. 3.6 (140/3912) Blood hemtocrit (%) 36 (33±40) vs. 39 (36±42), Blood cretinine level (mg/dl) 1.1 (1.0±1.5) vs. 1.1 (0.9±1.2) Blood cretinine level (.2 mg/dl) 6.8 (6/88) vs. 1.3 (51/3912), Sinus rhythm t preopertive EKG 74 (65/88) vs. 85 (3315/3912) Aortic cross-clmp time (min) 95 (74±131) vs. 78 (61±100), CPB time (min) 149 (115±202) vs. 109 (87±135), CABG opertion 58 (51/88) vs. 68 (2653/3912) VR 1 CABG opertion 13 (11/88) vs. 4.4 (172/3912), Need to perform circultory rrest.5 min 2.3 (2/88) vs. 0.4 (15/3912) CPB ow during the cooling phse (l/min per m 2 ) 2.3 (2.1±2.4) vs. 2.3 (2.2±2.4), CPB ow during the stble hypothermi phse (l/min per m 2 ) 2 (1.8±2.3) vs. 2 (1.8±2.2) 0.18 Blood pressure during the stble hypothermi phse (mmhg) 75 (60±80) vs. 75 (65±85) 0.17 CPB ow during the rewrming phse (l/min per m 2 ) 2.3 (2.2±2.5) vs. 2.3 (2.1±2.5) Minimum esophgel temperture reched (8C) 28.4 (27.0±30.0) vs (27.6±30.0) Minimum rectl temperture reched (8C) 30.2 (28.7±31.1) vs (29.6±31.5) Figures represent chnges percentge vlues followed by the proportion in prentheses s per Tbles respirtory condition hd stbilized, ptients were trnsported to the wrd for further recovery Sttisticl nlysis The dt re presented s medins (25 nd 75% percentiles in brckets) for continuous vribles or percentges for ctegoricl vribles. A commercil sttisticl pckge (SPSS for Windows Version 8.0; SPSS, Inc., Chicgo, IL) ws used for dt nlysis. Thirty-seven preopertive nd opertive vribles, including the type of pump employed for CPB (roller vs. centrifugl; Tbles 1 nd 2) were ssessed for their possible effect on the occurrence of the following outcomes, which were de ned s follows: In-hospitl mortlity: ny deth occurring within 30 dys fter surgery, or nytime before dischrge of the ptient from the hospitl; Permnent neurologicl de cit: centrl neurologicl de cit persisting.72 h; Com: unresponsiveness.24 h in the bsence of sedtion. All continuous vribles were rst tested individully (univrite sense) with the non-prmetric Mnn±Whitney test, while ctegoricl vribles were explored by the Chisqure (Ytes' continuity correction) or the Fisher's exct test when indicted. The fctors which were t lest mrginlly signi cnt (P # 0:2) by univrite nlysis were included into multivrible forwrd stepwise logistic regression model. The multivrite odds rtio (OR) for ech independent vrible in the nl regression models nd 95% con dence intervls were lso computed. The P vlue for entry of covrite into the model ws set t signi cnce level 0.05, while the P vlue for the removl of covrite ws xed t the 0.1 signi cnce level. Every multivrible model ws tested for relibility with the Hosmer±Lemeshow sttistic [11]. 3. Results 3.1. Ptient popultion The preopertive nd opertive clinicl fetures of the ptient popultion re reported in Tbles 1 nd 2, respectively. Brie y, the medin ge ws 65, 72% of the ptients were mle, 3.7% hd hd previous stroke, 7.2% were Tble 6 Results of multivrite logistic regression for in-hospitl deth Vrible OR 95% CI P vlue CPB time (min) ± Previous crdic surgery ± Blood cretinine level.2 mg/dl ± Blood hemtocrit (%) ± Hosmer±Lemeshow goodness-of- t-test, x 2 8 ˆ7:01; P ˆ 0:54.

5 A. Prolri et l. / Europen Journl of Crdio-thorcic Surgery 18 (2000) 575± Tble 7 Interction mong in-hospitl mortlity, neurologicl outcomes, nd type of pump In-hospitl mortlity Totl P Yes No % All ptients (n ˆ 4000) Periopertive com Yes No Totl , Periopertive permnent neurologicl de cit Yes No Totl , Ptients operted with centrifugl pump use (n ˆ 2213) Periopertive com Yes No Totl , Periopertive permnent neurologicl de cit Yes No Totl , Ptients operted with roller pump use (n ˆ 1787) Periopertive com Yes No Totl , Periopertive permnent neurologicl de cit Yes No Totl , redos, 13% hd history of hert filure, 68% underwent coronry rtery bypss grfting, 55% underwent surgery with the use of centrifugl pump, nd the medin CPB time ws 110 min. The clinicl vribles of ptients who underwent surgery using centrifugl or roller pumps re reported in Tbles 3 nd 4. Regrding preopertive vribles, the two groups of ptients were similr in ge, body surfce re, gender, history of hypertension, preopertive pulmonry, nd renl sttus; on the other hnd, ptients who underwent surgery with the use of centrifugl pump hd higher incidence of previous myocrdil infrction, insulin-dependent dibetes mellitus, were more frequently redos, nd hd higher incidence of previous trnsitory ischemic ttck (TIAs), strokes, nd overll neurologicl events. The nlysis of the opertive vribles showed similr frequencies in the different types of surgery, s well s in the need to perform circultory rrest, while ortic cross-clmp nd CPB times were, s expected, longer in cses using centrifugl pump. Finlly, there were sttisticlly signi cnt differences in perfusion pressures, ows nd tempertures between roller nd centrifugl pumps: pump ows were slightly lower in cses of centrifugl pump use, while pressures nd tempertures were slightly higher; however, in no cse did the differences between the two groups in CPB-relted vribles exceed 10% vrition, nd this ws reported s less thn 5% in most of the comprisons In-hospitl mortlity The overll in-hospitl mortlity rte of this series of ptients ws 2.2% (88/4000); there ws no difference between hospitl mortlities bsed on the type of pump, those being 2.3 (50/2213) nd 2.1% (38/1787) for ptients who were operted on using centrifugl nd roller pumps, respectively (P ˆ 0:860). The univrte risk fctors for in-hospitl deth re reported in Tble 5; nd the multivrite risk fctors for in-hospitl deth were longer CPB times, previous crdic surgery, blood cretinine levels. 2 mg/dl, nd lower blood hemtocrit levels (Tble 6). The interctions mong in-hospitl mortlity, neurologi- Tble 8 Signi cnt or borderline univrite risk fctors for periopertive permnent neurologicl de cit Vrible Periopertive neurologicl de cit vs. no periopertive neurologicl de cit P vlue Age t intervention (yers) 67 (63±72) vs. 64 (57±70) Previous vsculr surgery 8.6 (7/81) vs. 3.7 (145/3919) Peripherl vsculr disese 17 (14/81) vs. 10 (400/3919) Previous TIA 20 (16/81) vs. 6.5 (255/3919), Blood hemtocrit (%) 38 (35±40) vs. 39 (36±42) Blood cretinine level (mg/dl) 1.2 (1.0±1.4) vs. 1.1 (0.9±1.2) Blood cretinine level.2 mg/dl 4.9 (4/81) vs. 1.4 (53/3919) Sinus rhythm t preopertive EKG 75 (61/81) vs. 85 (3319/3919) Use of centrifugl pump for CPB 42 (34/81) vs. 56 (2179/3919) Aortic cross-clmp time (min) 85 (67±105) vs. 79 (61±101) CPB time (min) 122 (91±159) vs. 109 (88±135) Need to perform circultory rrest.5 min 2.5 (2/81) vs. 0.4 (15/3919) Minimum esophgel temperture reched (8C) 29.0 (27.2±29.8) vs (27.6±30.0) Minimum rectl temperture reched (8C) 30.4 (28.9±31.1) vs (29.6±31.6) Figures represent either percentge vlues followed by the proportion in prentheses or medin followed by 25th nd 75th percentiles in prentheses.

6 580 A. Prolri et l. / Europen Journl of Crdio-thorcic Surgery 18 (2000) 575±582 Tble 9 Results of multivrite logistic regression for periopertive permnent neurologicl de cit Vrible OR 95% CI P vlue CPB time (min) ± Previous TIA ± Age t intervention (yers) ± Use of centrifugl pump for CPB ± Hosmer±Lemeshow goodness-of- t-test, x 2 8 ˆ8:86; P ˆ 0:35. cl outcomes nd pump type re reported in Tble 7. Ptients who showed permnent neurologicl de cit or com hd higher in-hospitl mortlity rtes compred with ptients free from these complictions; similr results were obtined from seprte nlysis of ptients operted with centrifugl or roller pumps Anlysis of the risk fctors for the occurrence of periopertive permnent neurologicl de cit The signi cnt or mrginlly signi cnt univrite risk fctors for periopertive permnent neurologicl de cit re reported in Tble 8. Ptients who underwent surgery with the use of centrifugl pump hd permnent neurologicl de cit rte of 1.5% (34/2213), while the incidence of this compliction in ptients who were operted with roller pump ws 2.6% (47/1787; P ˆ 0:020). Multivrible logistic regression nlysis identi ed longer CPB times, previous TIAs nd incresing ge s multivrite risk fctors for periopertive permnent neurologicl de cit, while the use of centrifugl pump for CPB emerged s protective fctor (Tble 9) Anlysis of the risk fctors for the occurrence of periopertive com The signi cnt or mrginlly signi cnt univrite risk fctors for periopertive com re reported in Tble 10. Regrding the type of pump used for perfusion, ptients who underwent surgery with centrifugl pump hd periopertive com rte of 0.9% (20/2213), while the incidence of com in ptients who were operted using roller pump ws 1.8% (32/1787; P ˆ 0:020). Multivrible logistic regression nlysis identi ed longer CPB times, previous vsculr surgery nd incresing ge s independent risk fctors for the occurrence of periopertive com, while centrifugl pump use resulted s protective (Tble 11). 4. Discussion The continuous improvement of techniques in dult crdic surgery hs substntilly reduced the morbidity nd mortlity in crdic opertions requiring CPB. Despite these dvnces, however, dverse neurologicl nd neurobehviorl outcomes continue to occur, t perhps n incresed frequency, due to the progressive ging of the popultion of ptients undergoing crdic surgery [1,2]. To dte, severl studies ssessed the effect of CPB-relted vribles on neurologicl outcomes in dult ptients undergoing crdic surgery; in prticulr, it could be demonstrted tht longer CPB times [4,5] nd severity of scending ort therosclerosis [4,8] were strong predictors Tble 10 Signi cnt or borderline univrite risk fctors for periopertive com Vrible Periopertive com vs. no periopertive com P vlue Age t intervention (yers) 69 (64±72) vs. 64 (57±70) Preopertive weight (kg) 68 (60±72) vs. 72 (64±80) Body surfce re (m 2 ) 1.7 (1.6±1.8) vs. 1.8 (1.7±1.9) Previous crdic surgery 15 (8/52) vs. 7.1 (280/3948) Previous vsculr surgery 13 (7/52) vs. 3.7 (145/3948), Peripherl vsculr disese 21 (11/52) vs. 10 (403/3948) Previous RIND 5.8 (3/52) vs. 1.0 (43/3948) Previous stroke 12 (6/52) vs. 3.6 (141/3948) Blood hemtocrit (%) 35 (33±39) vs. 39 (36±42), Blood cretinine level (mg/dl) 1.2 (1.0±1.5) vs. 1.1 (0.9±1.2), Sinus rhythm t preopertive EKG 63 (33/52) vs. 85 (3347/3948), Use of centrifugl pump for CPB 38 (20/52) vs. 56 (2193/3948) Aortic cross-clmp time (min) 91 (76±126) vs. 79 (61±100) CPB time (min) 148 (111±181) vs. 109 (88±135), Need to perform circultory rrest.5 min 5.8 (3/52) vs. 0.4 (14/3948) Blood pressure during the stble hypothermi phse (mmhg) 70 (60±80) vs. 75 (65±85) Blood pressure during the rewrming phse (mmhg) 70 (65±75) vs. 70 (65±80) Minimum esophgel temperture reched (8C) 28.2 (27.0±29.3) vs (27.6±30.0) Minimum rectl temperture reched (8C) 30.0 (28.4±31.1) vs (29.6±31.5) Figures outside either prentheses represent percentge vlues or medin followed by 25th nd 75th percentiles in prentheses.

7 A. Prolri et l. / Europen Journl of Crdio-thorcic Surgery 18 (2000) 575± Tble 11 Results of multivrite logistic regression for periopertive com Vrible OR 95% CI P vlue CPB time (min) ±1.014, Previous vsculr surgery ± Age t intervention (yers) ± Use of centrifugl pump for CPB ± Hosmer±Lemeshow goodness-of- t-test, x 2 8 ˆ3:60; P ˆ 0:89. of periopertive neurologicl complictions, while lck of rteril line ltrtion [9,12] nd ph-stt cid±bse mngement [10] could lso increse the occurrence of postopertive centrl nervous system dysfunction. On the other hnd, the possible effects of other CPB vribles re still being debted, nd the roles of temperture mngement (normothermic vs. modertely hypothermic perfusion), men rteril pressure levels during CPB nd type of perfusion (pulstile vs. non-pulstile) in ffecting neurologicl compliction rtes hve not yet been completely de ned [13]. Centrifugl pumps hve been widely used s the min pump in dult crdic surgery, nd re considered by some uthors to be superior to the trditionlly used roller pumps becuse of less blood trum [14], reduced ctivtion of the cogultion cscde [15] nd improved biocomptibility [16], even if some of the studies could not document ny signi cnt bene ts in terms of hemolysis [17], pltelet dmge [18] or immune response [19]; in ddition, some recent evidence could document n incresed in mmtory response to CPB in cses using centrifugl pumps [20,21]. There is less informtion, however, on the effect of the use of this kind of pump on clinicl endpoints, nd the effects on neurologicl function re not well estblished yet; even if centrifugl pumps hve been shown to generte fewer microemboli thn roller pumps [22], it ws recently demonstrted tht, for CPB times of less thn 90 min, centrifugl pumps did not decrese serum S100b relese, mrker for cerebrl injury, compred with roller pumps [23]. In ddition, only one pper, by Klein nd collegues, hs previously evluted the effect of centrifugl nd roller pumps used for CPB on mny different clinicl outcomes, documenting reduced rte of neurologicl complictions when centrifugl pump ws used for perfusion; but no dditionl informtion ws given bout the criteri used to de ne neurologicl complictions in this pper [24]. The im of our study ws then to retrospectively review the dt concerning dult ptients who underwent coronry nd/or vlve surgery t our hospitl during 5.5-yer period (1994±June 1999); during tht period, in fct, both types of pump (roller nd centrifugl) were used t our hospitl t the sme time by the sme tem of surgeons, nesthesiologists nd perfusionists. Our study could show tht fctors relted both to the preopertive clinicl sttus of the ptients nd to opertive nd CPB fetures cn ffect the occurrence of mjor neurologicl complictions; ge t intervention, previous vsculr surgery, previous neurologicl episodes, s well s longer CPB times were risk fctors for dverse neurologicl outcomes of dult crdic surgery ptients, s previously described [13]. In ddition, our study documented tht the use of centrifugl pump cn reduce the rtes of the two most fered neurologicl complictions of routine dult crdic surgery performed with the use of CPB; univrite nd multivrite nlyses documented its protective effect, for the occurrence of both periopertive permnent neurologicl de cit nd periopertive com, reducing the risk reduction for the considered events by pproximtely hlf (multivrible ORs of 0.57 nd 0.46 for periopertive permnent neurologicl de cit nd periopertive com, respectively). Interestingly, the protective effect of centrifugl pump use could be documented even if there ws cler selection bis between the two pump types in our ptient popultion, nd centrifugl pumps were preferred, s previously stted, for cses with longer perfusion times. Also, the subgroup nlysis compring preopertive nd opertive vribles by the type of pump could con rm tht ptients operted with centrifugl pumps, side from the expected longer ortic cross-clmp nd CPB times, lso hd n incresed risk pro le for the considered events, being more frequently redos, insulin-dependent dibetics, nd hving higher rte of pre-existing neurologicl events; in fct, ll of these three fctors were previously documented s risk fctors for unfvorble neurologicl outcome [2]. The hypothesis to explin the protective effect of the centrifugl pumps used for CPB is, tht with centrifugl pumps, the embolic lod to the brin is lower [22], s ws previously demonstrted with ultrsonic microbubble detection in the rteril CPB line [25]. On the other hnd, the potentil neurologicl bene t of the use of centrifugl pump for perfusion ws not prlleled by decrese in in-hospitl mortlity; this nding hs no cler explntion to us, nd further investigtions will be needed to clrify this point. In conclusion, this study, with the limits of retrospective, non-rndomized study, suggests tht centrifugl pump use during routine dult crdic surgery reduced periopertive permnent neurologicl de cit nd com rtes. Prospective, multi-institutionl, rndomized studies will be needed to better de ne the possible protective effects of centrifugl pumps on neurologicl outcomes of dult crdic surgery. References [1] Cosgrove DM, Loop FD, Lytle BW, Billot R, Gill CC, Golding LA, Tylor PC, Goormstic M. 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