| Purpose:Absolute ethanol is the most effective liquid agent that can be used for endovascular treatment of AVMs.A fatal complication of arteriovenous malformations embolization with ethanol is the occurrence of acute cardiopulmonary collapse.The aim of the present study was to evaluate the effects of repeated intravenous bolus injections of absolute ethanol on cardiopulmonary hemodynamic changes and to investigate the predictability of ethanol-induced cardiopulmonary collapse in anesthetized rabbits.Methods: 1.Absolute ethanol was repeatedly injected through the femoral.The subjects were divided into a cardiopulmonary collapse group and a no-collapse group according to the development or absence of cardiac collapse.Hemodynamic changes were monitored.Factors affecting changes in hemodynamics were monitored and analyzed to investigate the predictability of ethanol-induced cardiopulmonary collapse.2.Postmortem,the lungs of rabbits were removed en bloc and fixed for histologic assessment and quantitative histomorphometry.The mean percentages of lung area occupied by ethanol?induced emboli was measured.The percentage of the total emboli at different diameter of vessels occluded on quantitative morphometric study of the lung was analyzed.3.Hemodynamic profiles were monitored after repeated intravenous bolus injections of absolute ethanol in anesthetized rabbits.Vagotomy was performed in the experiment group rabbits before the injection.Data were compared between experiment group and control group to explore the involvement of vasovagal reaction in the changes of hemodynamics and the occurrence of cardiopulmonary collapse.4.A clinical study was conducted in 62 patients with arteriovenous malformations who underwent endovascular therapy(101 sessions total)with absolute ethanol.Hemodynamic Changes during each sessions were analyzed and possible relationships were explored between these changes and the amount of ethanol used.Results: 1.Cardiopulmonary collapse was observed in 21(65.6%,cardiopulmonary collapse group)of 32 rabbits.Significant increases in the systolic,mean,and diastolic pulmonary arterial pressure were found in both groups during the sessions(P<0.05).Systemic arterial blood pressure measured immediately before the injection of absolute ethanol did not differ in the cardiopulmonary collapse group and the no-collapse group except that among animals with cardiopulmonary collapse,the injection immediately before the one causing cardiopulmonary collapse resulted in significant decreases in the systemic arterial blood pressure(18/21 case,84.7%;-9.37±11.66 mmHg P< 0.05).Systemic arterial blood pressure measured immediately before the final injection was significantly lower than the one measured before the injection prior to the final injection(57.76±12.76 mmHg vs 69.23±6.14 mmHg,P<0.05).2.The percent of lung area occupied by ethanol?induced emboli measured in the inferior lobe of right lung(0.0287±0.0075)was significantly higher the other lobes(P<0.05).The percentage of the total vessels occluded by the emboli at different diameter of vessels in cardiopulmonary collapse group were significantly higher in 30-60μm vessels(0.5405±0.0901 vs 0.4504±0.0663,P<0.05)and lower in <30μm vessels(0.1072±0.0463 vs 0.1555±0.0396,P<0.05)than in no-collapse group.The percentage of the total vessels occluded by the emboli at bronchial artery was significantly higher in cardiopulmonary collapse group than in no-collapse group(0.1768±0.0922 vs 0.1100±0.0736,P<0.05).3.The values of mean systemic arterial blood pressure measured immediately before the injection causing cardiopulmonary collapse were(59.57±12.20 mmHg vs 57.12±9.37 mmHg,respectively,P>0.05)in the two groups.The values of mean pulmonary arterial pressure measured immediately before the injection causing cardiopulmonary collapse were(18.02±1.02 mmHg and 15.35±3.35 mmHg,respectively,P>0.05)in the two groups.The difference between post and pre values of mean systemic arterial blood pressure after the injection immediately preceding the one resulting in cardiopulmonary collapse were(-10.60±9.85 mmHg vs-7.40±10.56 mmHg,P>0.05).The difference between post and pre values of mean PAP after the injection immediately preceding the one resulting in cardiopulmonary collapse were 4.92±1.01 mmHg;and 3.16±1.99 mmHg,respectively(P>0.05).4.Systemic arterial blood pressure and heart rate increased after ethanol injection in most sessions(90 in 101 sessions,89.1%).Systemic arterial blood pressure(systolic,mean,and diastolic),and heart rate(HR)were significantly increased during treatment sessions(P<0.05).Differences between initial and highest systemic systolic blood pressure(38.4± 23.3 mmHg)and heart rate values(27.8 ± 15.7 bpm)were positively correlated with the total dose of ethanol injected respectively(R=0.251,P=0.028;R=0.327 P=0.004,respectively).Systemic arterial blood pressure decreased in 11 sessions(11 in 101 sessions).Univariate analysis found amount over the mean value(0.203±0.107mL/kg)was a weak positive predictor of the decrease(P<0.05).Conclusions: 1.Repeated intravenous bolus injections of absolute ethanol commonly result in a significant increase of pulmonary artery pressure.Hemodynamic profiles obtained immediately before intravenous injection of absolute ethanol did not predict the subsequent occurrence of cardiopulmonary collapse except after the injection immediately preceding the one resulting in cardiopulmonary collapse.In this animal model,significant decreases in systemic arterial blood pressure occurred after the injection immediately preceding the one resulting in cardiopulmonary collapse.A sudden decrease in systemic arterial blood pressure might be considered as a predictive factor.2.There was directly relationship found between the amount of ethanol?induced emboli and the occurrence of cardiopulmonary collapse based on histologic data of the investigation.Compared with no-collapse group,a higher occupation in 30-60μm diameter of vessels and in bronchial artery might be involved in the pathogenesis of hemodynamic changes and cardiopulmonary collapse induced by absolute ethanol.3.Despite a mild increase in systemic arterial blood pressure after vagotomy,however,there was no evidence of involvement of the vasovagal reaction in hemodynamic changes and cardiopulmonary collapse induced by absolute ethanol.4.Systemic arterial blood pressure and heart rate increasing during absolute ethanol embolotherapy are common,temporary and were positively correlated with ethanol dose.Decrease of systemic arterial blood pressure may occurred.Amount of ethanol injected were weakly predictive of occurrence of hypotension.Although,decrease of systemic arterial blood pressure was temporary in most cases,it might be a potential prediction of cardiopulmonary collapse and should be managed carefully. |
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