Duplex Scnning Techniques

Transcription

1 -'.' D Venus wll functin in the pthgenesis f vncse vems G. Hether Clrke, PhD, S. N. Vsdekis, MD, J. T. Hbbs, FRCS, nd A. N. Niclides, MS, Lndn, U.K., nd,i\.felburne, Austrli the cuse i uricse ueins, citing wunrespect t these three fctrs. Duplex scnning techniques were used t ssess the venus vlves, nd simultneus mesurements f clj vlume (strin-guge plethysmgrphy} nd venus pressure mde dunng venus cclusin plethysmgrphy were used t determine the elsticity f the venus wll nd the Tle f rteril inftw. Fifty-ne cntrllegs nd36 legs with superficil venus insufficiency were exmined. Risk fctrs were used tq divide the cntrllegs int tw grups: lw risk r nrml (23 legs) nd high risk (28egs). The results btined in the high-risk limbs demnstrted significntly reduced vein wll elsticity (p < 0.001) nd incresed rteril inftw (p < 0.005) cmpred with the nrmllimbs, with n crrespnding in crese in the incidence f vlvulr incmpetence. }""", """t" rl"n ".,""",,1 tj,nlthe rle the vein wll n t e Tle rter n w. Frm the lrvine Lbrtry fr Crdivsculr lnvestigtin nd Reserch, Acdemic Surgicl Unit, St Mry's HsPitl Medicl Schl, Lndn, U.K. V ARCOS VNS AR ASSOCA TD, by definitin, with incmpetent mlfunctining vl ves nd dilttin nd wekening f the vein wlls. t is nt cler, hwever, whether the vlvulr incmpetence ccurs first nd prduces the vein wll dilttin r vice vers. Three theries hve evlved t explin the cuse f vricse veins, ech ttributing their develpment t n inherent primry fctr.1 The three fctrs prpsed re wekness f the venus vlves,l, 2 wekness f the vein wll,,3 nd multiple rterivenus cmmunictins.l, 4 The sscitin between vricse veins nd mlfunctining venus vlves r dilted vein wlls is self-evident. This is nt s with multiple nstmses. The ltter ws prpsed initilly rterivenus n the bsis f seril rterigrphy4 demnstrting n bnr- SupfOrted bythe Crdivsculr Disese ductinl nd Reserch Trust, the Greek Stte Schlrship Fundtin, nd the Schll Fundtin. Accepted fr publictin Jn. 21, Reprint requests: Hether Clrke, Deprtment f Medicl Rditins Science, Ryl Mlbume nstitute f Technlgy, Melbume, Victri 3001, Austrli. 11/56/28745 mlly rpid mvement f bld frm the rteril t the venus system in limbs with vricse veins nd peripertive visuliztin f direct rterivenus cmmunictins with n perting micrscpe. Subsequent nninvsive investigtins tht used plethysmgrphic techniques indicted tht the mximum rteril inflw t the limb ws significntly higher in limbs,vith vricse veins.5-7 The exct nture f the cmmunictins hs nt been estblished, hwever, nd there is n evidence t refute the suggestin tht they might be dmged nd dilted cpillry vessels.8 The reltive etilgic rles f the three fctrs prpsed hve nt been reslved by previus investigtin. This missin my lrgely be ttributed t the bsence f ny estblished methd f ssessing venus wll functin nd the prblems f identifying ptients in the erly stges f develpment f vricse veins suitble fr such etilgic studies. The develpment f methd fr determining the elsticity f the venus wll in viv hs helped t vercme these difficulties.9, 10 The im f this study ws t i.nvestigte nrmllimbs, high-risk limbs, nd limbs with estblished vricse veins by evluting the venus vlve functin, the vein 402 SURGRY

2 Vlume 777 Number 4 V enus ll junctin nd vricse veins J: -- 90% (RP-AVP) n RP AVP RT90-.l 1 Time - Fig. 1. Schemtic drwing f typicl mbultry venus pressure recrding shws the resting pressure (RP) the mesured mbultry venus pressure (AVP), nd 90% refilling time (RTg). wll functin, nd the rte f rteril inftw, in n ttempt t determine the cuse f vricse veins. MATRAL AND MTHODS Subjects. Twenty-three vlunteers (32imbs) nd 36 ptients (55 limbs) referred frm the vein clinic were investigted. (Cre,vs tken t exclude subjects wh were tking vsctive medictin r wering elstic supprt stckings.) The 87 limbs studied were cmprised f 51 cntrllimbs nd 36 limbs with superficil venus incmpetence nd nrml deep veins. The cntrl limbs included bth vlunteer limbs (n = 32) nd the pprently nrml cntrlterl limbs f ptients with unilterl venus disese (n = 19). These cntrl limbs were clssified int tw grups f nrml nd high-risk limbs ccrding t the fllwing criteri: (1) fmily histry f vricse veins, (2) ccuptin invlving stnding, (3) histry f symptms r signs sscited with vricse veins, (4) presence f reftux detected with Dppler ultrsngrphy, nd (5) bnrml mbultry venus pressure recrdings: mbultry venus pressure greter thn 40 mm Hg nd 90% refilling time (R T 90) less thn 18 secnds. f tw r mre f these criteri were present, the limb ws clssified s being t high risk f develping vricse veins (28 limbs). Otherwise they were clssified s nrml (23 limbs). The mteril used in this investigtin therefre is cmprised f subjects in whm nly ne limb ws studied nd subjects in whm bth limbs were studied nd clssified either in the sme grup r in different grups. The distributin f ptients ws llwed fr in the sttisticl nlysis f the mesurements btined by clculting n djusted stndrd errr.. Methds f investigtin. Fur investigtive prcedures were perfrmed in this study: mbultry venus pressure mesurements,10,11 duplex Dppler scnning,10, 12, 13 ssessment fvenus elsticity,9,10 nd mesurements f mximum rteril inflw.5-7, 10 The mbultry venus pressure mesurements were perfrmed t ssist in selecting the high-risk limbs. The etilgic studies,vere bsed n the ther three methds f investigtin. Duplex Dppler scnning,vs used t ssess the vlve functin, the mesurement f venus elsticity t ssess venus wll functin, nd the mesurements f mximum rteril inflw t ssess rteril inflw. Ambultry venus pressure mesurements. Ambultry venus pressure ws mesured directly by cnnulting vein n the drsum f the ft. The ptient ws sked t stnd, hlding frme fr supprt nd llwing the bseline resting pressure t be estblished. The ptient ws then sked t perfrm 10 tipte mvements t rte f ne per secnd t empty the veins nd then t remin still while the veins refilled. The tw mesurements tken frm these recrdings were the mbultry venus pressure, defined s the pressure immeditely fter exercise, nd the R T 90, which is the time tken fr the pressure t effect 90% recvery f the preexercise level (Fig. 1). Duplex Dppler scnning.10,12 Duplex scnning ws used tssess vlvulr efficiency in the lwer-limb veins f the subjects studied, with 7.5 MHz imging prbe cupled with 5 MHz Dppler crystl (DRF 300; Disnics ncrprted, Milpits, Clif.). The prbe ws plced yer the vessel f interest, nd the Dppler smple vlume ws psitined within the vein s tht the ngle f insntin ws pprximtely 60

3 404 Clrke el l. Surgery APril cm Thlgh Cutt nflled l 80 mmhg 2 1 ;:;;-- / ' "'-- Fig. 2. Simultneus mesurement f pressure nd vlume with prximl cclusin. degrees. Mnulcmpressin f the limb ws pplied distlly, prducing n utaw fbld. The presence f retrgrde Aw n relese f cmpressin indicted vlvulr incmpetence. This methd ws used t determine the functin f the vlves in the deep (femrl, pplitel, gstrcnemius, psterir tibil, nterir tibil, nd pernel) nd superficil (lng sphenus, shrt sphenus, nd Gicmini) veins f the lwer limbs. (The Gicmini vein scends frm the prximl prt f the shrt sphenus vein deep in the psterir spect f the thigh, prllel t the skin, nd termintes s the pstermedil tributry f the lng sphenus vein.) Vritins frm the stndrd ntmy f the lwer-limb venus system re frequent, nd the investigtins f the vlve functin were mdified t the requirements f the individullimb, exmining ech vein t multilevels t ensure tht there ws n lclized incmpetence. Mesurement í venus elsticity.9, 10 The elsticity f the l,ver-limb venus system ws ssessed by stndrd strin-guge plethysmgrphy nd direct mesurements f venus pressure (Fig. 2). The ptient ws plced supine with ne leg elevted 27 cm t the heel t llw the veins t empty. The knee ws Aexed nd rtted externlly, nd the thigh ws supprted t ensure tht the leg,vs relxed. Strin-guge plethysmgrphy ws perfrmed with n electriclly clibrted mercuryin-silicne rubber strin guge plced rund the clf t the mximum circumference, líwing percentge vlume chnge t be determined. Mesurements f venus pressure were btined by inserting 21-guge butter- Ay needle in vein n the drsum f the ft. The strin-guge plethysmgrph nd pressure mnitr were cnnected t t,v-chnnel chrt recrder, llwing simultneus mesurements f pressure nd vlume t be mde. The pressure-vlume reltinship f the l\ver-limb venus system ws then btined by plcing 17 cm \vide cuff rund the thigh nd inflting it t 80 mm Hg t cclude venus utflw. The subsequent chnges in pressure nd vlume were recrded simultneusly nd crrespnding redings f pressure nd vlume were tken frm these recrdings t 15-secnd intervls nd pltted n grph (Fig. 3). The chnge in pressure (P) nd the crrespnding chnge in vlume (V) were mesured in the liner, high-pressure prt f the pressure-vlume curve (Fig. 3). This liner regin f the curve nd the initil slpe \vere extrplted, s shwn in Fig. 3, t btin V, the theretic vlue f the initil vlume pertining t the chnges in vlume t high pressures. The elsti.c mdulus (K) ws clculted by substituting P, V, nd V, s shwn in equtin 1. This ws cnverted t S units f Nm-2 with stndrd cnversin fctr frm millimeters f mercury (132.9): K = P/V /V (1). This methd f clculting K is inherently vrible bec use f the difficulty in determining the extent f the liner regin f the curve nd selecting the grdient. T stndrdize this mximum nd minimum grdients \vere btined frm ech grph, nd the men vlue ws used t clculte K. Mesurement í mximum rteri! inflw.5-7,10 The mximum rteril inflw ws mesured frm the plethysmgrphic recrding btined in mesuring the venus elsticity. The mximum rteril infl\v ws determined frm the initil slpe f the recrding, s illustrted in Fig. 4, nd expressed in units f percentge vlume chnge per minute. The grdient f the initil slpe f the vlume curve ws nt lwys cler, becuse n sme recrdings there ws very shrp chnge in vlume initilly, nd the subsequentchnges in vlume were mre typicl. This

4 L ọē Q) ;:, "O > Pressure (mmhg) Fig. 3. Schemtic drwing shws the clcultin f the elstic mdulus frm the pressure vlume reltinship. / Plteu / ọ / 1/ Ē- g 11 2% MAl /mln) JJ m Cuff nfltln Time. Fig. 4. Schemtic drwing shws the clcultin f the mximum rteril infl\v (MAl) frm the strin-guge plethysmgrphic recrding. initil rtifctul chnge in vlume my be ttributed t ne f tw cuses: ptient mvement r rpid distl mvement f the bld in the veins beneth the ccluding cuff. The mximum rteril inflw in these limbs ws mesured by determining the initil grdient f the curve relting t the subsequent chnges in vlume. RSULTS Duplex Dppler Lindings. The presence f vlvulr incmpetence in the superficil veins nly ws estblished in ll the limbs with primry vricse veins nd in fur f the high-risk limbs; in the remining 24 highrisk limbs nd ll f the nrmllimbs n sites f reflux were detected (Tble 1). t shuld lg be nted tht the re flux fund in the fur high-risk limbs ws cnsistently evident in nly ne limb; in the ther three limbs it ws detected n ne visit but nt n subsequent visit This phenmenn hs been described s intermittent reflux. These findings were sttisticlly cmpred with x2test (Tble 11). Mesurements í K. The mesurements f K btined in the three grups f nrml, high-risk, nd primry vricse veins re shwn in Fig. 5 n lgrithmic scle. t is clerly evident tht K is higher in the nrml grup thn in either the high-risk grup r the grup f limbs with primry vricse veins, nd

5 406 Clrke et l. Surgery April Tble l. Summry f results f etilgic investigtins, vl ve functin (re(fux), K, nd rteril inftw Reflux N f limbs 0;. K (104 Nm-2) Men Rnge j: 2 SD MAl (mljdljmin) Medin Rnge N. f limbs N HRG SV 13: N, Nrmllimbs; HRG, rugh-risk limbs; SV, Jimbs with superficil vein incmpeten; MAl, mximum rteril inflw. there is n discernible difference in elsticity between the ltter. The mesurements f K were trnsfrmed t nrml distributin by tking lgrithms. The men nd rnge given in Tble 1 were btined by clculting the men nd the men ::!: 2 SD fr the trnsfrmed dt nd tking ntilgrithms. The.levels f significnce given in Tble 11 were btined by pplictin f the Student t test t the trnsfrmed dt (p < 0.001). Mesurements í mximum rteril inflw. The mesurements f rteril inflw btined in the three grups f limbs investigted re shwn in Fig. 6, nd the men nd rnge re given in Tble l. These mesurements re nt nrmlly distributed, s the Mnn- Whitney U test ws used fr sttisticl cmprisn between the three grups. This shwed tht the mximum rteril inflw is significntly higher in the high-risk limbs (p < 0.01) nd in the limbs with primry vricse veins (p < 0.005) thn in the nrmllimbs, but n significnt difference ws fund between the Crrer (Tble 11). tilgic findings. The resultsbtined re summrized in Tble 1, giving the incidence f vlvulr incmpetence, the men nd rnge f K, nd the medin nd rnge f the mximum rteril inflw in the three gróups f nrml, high-risk, nd primry vricse veins. The sttisticl significnces f these findings re summrized in Tble 11. These results indicte tht there is significnt difference in the verll findings f ll three investigtins between the nrmllimbs nd the limbs with primry vricse veins. The results frn} the high-risk limbs demnstrte tht lthugh K nd the mximum rteril inflw mesured in these limbs re cmprble with Tble 11. Cmprisn bet"leen the three grups f limbs studied f the sttisticl significnce (p vlue) btined with the three methds f ssessment used: vl ve functin (reflux), K, nd rteril inflw Reflux K Arteri! inflw N, Nrml; HRG, high risk; SV, superficil vein incmpetence. these sme mesurements in the ptients with estblished vricse veins, there is n crrespnding similrity in the incidence f vlvulr incmpetence. DSCUSSON The findings f n etilgic investigtin re strngly influenced by the ptients investigted nd the methds f investigtin used. The frmer is imprtnt bec use the prgressin f given physilgic chnge is dependent n hw fr the disese hs prgressed. The ltter is lg imprtnt becuse it ffects the sensitivity f the investigtin t detecting the physilgic chnges, prticulrly in the erlier stges. The identifictin f limbs in the erly stges f develping vricse veins is therefre crucil. n this study these limbs were fund frm the cntrl ppultin, which ws cmprised f nrmllimbs frm vlunteers nd ptients with unilterl venus disese. Recent studies hve shwn the presence f venus disese in the pprently nrml cntrlterllimbs f ptients with unilterl venus ulcertin.13 xtending this ide, it is nt unresnble t s sume tht ny pprently nrml limb might hve sme degree f venus disese. t is the identifictin f these cntrl limbs with subclinicl disese tht is difficult. This hs been chieved in this study by cmbintin f risk fctrs nd mesurements. The limbs ssumed t be in the erly stges f develping vricse veins hve in fct been referred t s high-risk grup, becuse this is pprprite t the methd f clssifictin used, nd until fllw-up studies re perfrmed,there is n evidence t shw tht they will develp vricse veins. Fur f the limbs clssified in the high-risk grup were fund t hve reflux in the lng sphenus vein. Despite hving incmpetent vl ves in their lng sphenus veins, these fur limbs were nnetheless clssified in the high-risk grup, becuse n clinicl exmintin they ppered nrml, hving n visible vricsities nd n evident signs f venus disese.

6 Vlume 111 Number 4 Venus wl(functin nd vricse veins N- z 1, )(. " 9-..! UJ ::. l.. i. (:,. l. -. c: ( j 1. l " i 0.1 N HRG SV Pllenl Grup Fig. 5. lstic mdulus (K) fr the three ptient gl"ups. N, Nrml; HRG, high risk; SV, superficil vein incmpetence. The ther spect f this study tht shuld be cnsidered is the sensitivity f the methds f investigtin used in detecting erly physilgic chnges. The techniques used fll int tw ctegries: duplex scnning prvides n ntmiclly specific nd lclized ssessment f the presence f reflux in individul veins within the limb, nd the ther tw techniques prvide n verll nd generlized ssessment f the limb The lclized nture f the duplex scnning technique indictes the imprtnce f n extensive nd thrugh exmintin t minimize the pssíbility f missing ny lclized incmpetence. The duplx exmintin perfrmed in this study ws bth creful nd extensive, checking the deep nd superficil veins t multilevels fr sites f reflux. This exmintin cnnt exclude histlgic chnges in the venus vl ves, but in terms f the etilgic theries it is the functin f the vl ve tht is imprtnt, bec use in the presence f vlvulr cmpetence there is n incresed pressure distlly t prduce lclized dilttin f the vein wll. Ptient HRG Grups Fig. 6. Mximum rteril inflw (MAl) fr the three ptient grups. N, Nrml; HRG, high risk; SV, superficil vein incmpetence. The generlized nture f the plethysmgrphic techniques indictes tht the ssessment f venus elsticity nd rteril inftw mr be less sensitive t sm!! r lclized chnges, prticulrly if they re lclized prximl t the clc The results btined shw incresed rteril inftw nd decresed elsticity in the high-risk limbs but n crrespnding increse in the incidence f vlvulr incmpetence. The thrughness f the duplex exmintin precludes the explntin f this finding in terms f undetected lclized incmpetence. These results d nt differentite between the rles f the vein wll nd the rteril inftw. This mr indicte tht the selected high-risk limbs hve venus disese tht hs prgressed beynd stge in which nly ne physilgic pwmeter hs chnged. Alterntively this mr indicte tht the chnges in these tw physilgic prmeters re interctive nd effectively ccur simultneusly. The thery prpsed t explin the develpment f vricse veins in terms f rterivenus mlfrmtins4 is bsed n the premise tht the nstmses re multiple nd lclized nd prduce lclized chnges in the SV

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