Effect ofacutealterations inafterload on left ventricular function inpatients withcombined coronaryarteryandperipheral vascular disease

Objective-To assess theeffect ofacute alterations in afterload by aortoiliac clamping,duringperipheral vascular surgery,on left ventricular function. Design-Prospective examination ofthe left ventricular longaxisandtransmitral Dopplerflowpreoperatively andintraop- eratively; before aortic clamping, during clamping and5min,15min,and5days after unclamping. Setting-Atertiary referral centrefor cardiacandvascular disease equipped withinvasive andnon-invasive facilities. Patients-20 patients (11men; mean (SD) age 61(8)years) withsignificant aorto- iliac disease anddocumented coronary arterydisease and21normalcontrols of similar age. Results-Preoperatively: longaxis func- tionwas abnormalcomparedwiththatin normalcontrols. Insystole total longaxis excursion andpeakshortening ratewere reduced, onsetofshortening delayed, and therewas pre-ejection lengthening (P< 0.001). Indiastole therewas abnormal shortening duringisovolumic relaxation, delaying theonsetoflongaxislengthening (P< 0.001). Peaklengthening ratewas alsoreducedand A wave excursion increased(P< 0.001).Transmitral Dopplershowedincreased A wave veloc- ityandreducedpeakE/Adiastolic flow velocities ratio (P< 0.001).Intra- operatively: preclamping results didnot differ fromthosebeforeoperation. With clamping the extent of systolic and diastolic abnormalities promptly increased as toa lesser extentdidthoseof transmitral flowvelocity, although heart rateandbloodpressure didnotchange significantly. Totallongaxisexcursion andA wave amplitude were more reduced byaortic thaniliac clamping, whereasthe onsetoflengthening was more delayed and the lengthening velocity more reducedwithiliac clamping. Some5min afterunclamping systolic longaxisfunc- tionhadalready returned towards nor- mal;total excursion increased, as didthe peakshortening rate,and theonsetof shortening became lessdelayed(P< 0.001). Indiastole thedelayed onsetof lengthening regressed, itslengthening velocity increased, andA wave excursion feli(P< 0-001). Earlydiastolic transmi- tralflowvelocity alsoincreased. This improvement in systolic and diastolic longaxisfunction hadprogressed 15min after unclamping butshowednofurther changeat5days.At5daysafter opera- tion, however, systolic anddiastolic mea- surements hadimproved comparedwith thosepreoperatively. Conclusion-Resting left ventricular long axisfunction isabnormal inpatients with combinedcoronaryarterydisease and peripheral vascular disease. Itisunaf- fectedby anaesthesia butdeteriorates withaortic oriliac clamping, although bloodpressure remainsunchanged. It promptly improves withunclamping after successful peripheral arterial reconstruc- tion.Thus,evenin apparently stable coronary artery disease, resting subendo- cardial function islabile, showingpro- nounced alterations with changing after-load, evenwhenarterial pressure itself doesnotchange. (Heart 1996;75:151-158)