The Effects Of Different Limb Remote Ischemic Postconditioning On Serum Concentration Of Ctnt And TNF-α During Volve Replacement Sugery

Objective Enormous animal experiments and a few clinical trials revealed thatremote ischemic postconditioning can reduce the myocardial ischemia-reperfusion injury. However, it’s rarely reported that whether the treatment ofremote ischemic postconditioning can protect ischemia-reperfused myocardiumduring valve replacement surgery. This project is to investigate observe theeffects of two ways of limb ischemic postconditioning on serum cTnT andTNF-α concentrations during valve replacement surgery in adult patients.Another objective of the study is to investigate myocardium protective effect ofthe two different remote ischemic postconditioning and the relationship withthe inflammatory response. Methods45patients with rheumatic heart diseasewho are scheduled for valve replacement surgery under cardiopulmonarybypass were enrolled and randomly divided into three groups: controlledgroup(group NS), lower limb ischemic postconditioning group(group L),combined upper/lower limb ischemic postconditioning group (group UL), n=15.All patients were premedicated with penehyclidine0.01-0.15mg/kg byintravenous injection. In three groups, anesthesia was induced with intravenousinjection of Sedation、analgesia、muscle relaxants, followed by intratrachealIntubation, and maintained by continuous infusion of Sedation、analgesia andmuscle relaxants. During cardiopulmonary bypass, when aorta declamped,tourniquet fasted on the left lower limb(8.5cm wide, the lower edge is3-4cmaway from knee joint) was inflated by pressure of300mmHg, which lasted for5minutes to block the bloodstream of the extremity, then deflated reperfusedfor5minutes. The above process repeated for3times (30minutes in total) ingroup L. MAP was maintained in the range of60-70mmHg during CPB. In thegroup UL, when aorta declamped, the tourniquet fasten to the left lower limb (wide8.5cm, the lower edge3-4cm away from knee joint) and the tourniquetfasten to the right upper limb were inflated, last for5minutes (pressuremaintained at300mmHg and250mmHg) to block bloodstream to right upperand left lower extremities, then deflated for5minutes (reperfusion). The aboveprocess repeated3times (30minutes in total). MAP was maintained in range of60-70mmHg during CPB. In group NS, no limb treatment processed. SpO2、HR、ECG、CVP、SBP、DBP、MAP and ETCO2were monitored intraoperatively,and duration of CPB, automatic cardiac rebeating rate, aortic declamping time,ICU staying time，time for use of vasoactive drugs and other clinical indicatorsrecorded. The artery blood samples were collected for the measurements ofserum concentration of cTnT, TNF-α immediately after anesthesiainduction(H0), at2h after aorta declamping (H1), at6h after aorta declamping(H2), at12h after aorta declamping (H3), at24h after aorta declamping (H4)respectively. Results1.There were no remarkable difference in age, weight,gender, preoperative heart rate, preoperative EF, surgical approaches, and MAPamong three groups(p>0.05).2.There were no remarkable difference induration of CPB, aorta occlusion time, ICU staying time and time for use ofvasoactive drugs among three groups(p>0.05).There were no abnormalityobserved in extremities during the follow-up period in both L groups and ULgroups.3.There was no difference, during the trial, in HR、MAP、CVP amongthe three groups（p>0.05).Comparing with H0, there were no remarkabledifference the in HR、MAP、CVP in all groups at H1, H2, H3and H4(p>0.05)4.Automatic cardiac rebeating rates in group L、group UL were significantlyhigher than that in group NS (p<0.05).5.Troponin-T:①There was nosignificant difference in the serum concentration of troponin-T among threegroups at H0(p>0.05);②Comparing with H0, the serum concentration oftroponin-T increased markedly in all groups at H1, H2, H3and H4(p<0.05);③The serum concentration of troponin-T was significantly lower in the group L, UL than that in the group NS at H1, H2,H3and H4(p<0.05);④Nodifference was observed in the serum concentration of troponin-T between thegroup L and group UL at H1, H2, H3and H4(p>0.05).6TNF-α:①There wasno difference in the serum concentration of TNF-α among three groups at H0(p>0.05);②Comparing with H0, the serum concentration of TNF-α increasedmarkedly in all groups at H1, H2, H3and H4(p<0.05).③The serumconcentration of TNF-α was significantly lower in the group L, UL than that inthe group NS at H1, H2, H3and H4(p<0.05).④No difference was observed inthe serum concentration of TNF-α between the group L and group UL at H1,H2, H3and H4(p>0.05).7. Correlation analysis revealed a Linear positivecorrelation between the serum concentrations of troponin-T and TNF-α.Conclusion1. Both left lower limb ischemic postconditioning and combinedright upper limb/left lower limb ischemic postconditioning can effectivelyattenuate the increase of serum cTnT concentration after aorta declamping, andimprove the automatic cardiac rebeating rates, which revealed that bothmethods are effective in myocardial protection.2. The two methods ofpostconditioning can attenuate increase of serum cTnT concentration in similarmanner and to similar extent, which suggests that the myocardial protectioneffect of multiple limbs ischemic postconditioning is not superior to single limbischemic postconditioning.3. Both methods of postconditioning are effective inthe inhibition of serum TNF-α concentration and there is a significantcorrelation between changes of serum cTnT and TNF-α concentration, whichsuggests myocardial protective effects of both methods, may be related to theinhibition of systemic inflammatory response syndrome.4. During the trial,hemodynamic data, duration of ICU stay and use of vasoactive drugs were nosignificantly different among three groups of patients. No any injury occurredin limbs treated with ischemic postconditioning in both test groups, whichsuggests that the methods of remote ischemic postconditioning applied in thisstudy are simply practical, non-invasive, effective and safe.