Thermal methods for therapy of nonvariceal bleeding

IN 19~9. T l IE NATIONAL INSTITUT ES ofl-l ealih (NIH ) Conscnsu Confe rence on EnJo~copic Thernpy nf Peptic Ulcer Disea~c w ncluded that four cmlt,scopic therapies ofhlccding peptic ulcer should he considered: multipolar clcctrocoagularion (Ml'EC) , heater probe, Nd :YAG laser and injection 1hernpy ( I ). The ~!l'E<.' and heat prohc were rared most prcfe rahle because nf their safety, efficacy, low cost and portability. The Nd :YAG laser was deemed cffccti \'e hut less desirable hecausc it was les~ portable and more skill \\'a~ required to use it. Monopnlm electrocnagulat ion , electrohydrothermal therapy and microwave therapy are the thermal technologies which currently have little rnlc.


COMBINATION THERAPY
Rutgcerts ct al (2) has studied and popularized the method using com.bination t hcrapy fnr peptic ulcer bleeding.By injecting the bleeding site wiLh 1: 10,000 adrenali ne prior to the instituti(ll1 of thermal therapy, Rurgeen s' group believes thar the efficacy of treatment can be increased.The logic is that rhe adrenaline will cau,c vasoC()n- scncnon whi ch constricts the ,irtery, making it less <1 pt ro bleed, and fac ilitates the heat sink effect (if there i, le,s moving blood flowing through the artery, less heat will he carried aw.iy, making the thermal treatment more effic ient).In <1ddi tion , the edema which is caused from the i niect1on ll'i 11 also cause some comprc,sion on the vc~sel making it less likely to bleed.Some cxpcrimcnrnl work by Lam and colleagues (3 ) cvalu,11 cd mural weakness and tissue effccL s induced hy thermal and injectio n therapy in a porcine small bowel model.T hey wi~hcd L O determine what thermal and injection therapie , both alone and in cnmhination, arc due to wall ~trength to provide information ahout the risk of perforation when combined d,crapics arc employed.They J ctcrmincJ the mural weaknes~ was most marked L wo Jays ;1ftcr thermal injury wall strength returned to normal after four day~.Alcohol injection alone and alcohul followed by BlCAP or hc<1ter prnhc docs m1t reduce wall strength.Adrenaline alone also doc~ not reduce wall ~trength , hut a'-lrcnalinc followed hy either BICAP or heater probe treatment dccrc, 1~cs wa ll strength .In a clinical ~tudy by Rutgccrrs <1nd colleagues (2), adrenaline plus polidocc1110l was found w he more effective thc111 adrenaline plu~ Y AG laser therapy, wh ich is more effecti ve than adrenaline alone fo r bleeding peptic ulcers.

C eorgewwn
. COMPARATIVE DATA In an attempt en understand beut•r which of the thermal methods b 111\lsl desirable, it i., useful lo rev iew several studies uimparmg differem endoscl,p1c therapies.In a multicenrre emlnscopic trial, Jensen ct al ( 4, 5) fnund thm hoth the Hit',\ r and heater prnht• wt• re superior to no endoscopic thernpy for pauenls with acuvcly hlced111g ulcer, compared wnh nonhlecding ulcers with , i-.,ihlc vesseb.The RICAP and heater pro he were s11rn lar when comrared for numhcr of day:, in the inten-,ive care unit, number of blllllll tranv fusions, need fm ulcer surgery, ulcer healing rates and lllllrtality during hosp1tal 1:at ion.Matthewson er al (6) compa red the Nd:Y A(, laser with heater pnihc for control o( ,1ctively hlccd111g ulcers and nonbleeding visihlc vessels.Then: was nn srnllst1call), s1gn1fic,ml difference 111 morrnlny between the grnups, but rehlet•ding in laser-treated patients w,h b,s than in the control gro11p and heater probe-treated patients.The ,lllthnrs (6) found the YAG l.hcr supcnm to the heater pmbe.L111 t'l a l (7) random i:ed 61 patients with nonhlccding , 1sd1lc vessels lO e ithe r hc:ncr prohe treatment or conservati l'e man,1gemen1 \\'ithout enJ11scopic therapy.There was no stalisucall y significant difference bet ween the two groups 111 rate of rchlccd111g; add1lionally, 1he ,issurancc nf ultimate hernosw,b, number of bln1xl trans-fu~ions requirt•d, durnt 1011 of hnspnali:ation and e,•cntual mortality were similar.H llWl'\'t'r, rht• need for emergency su rgica l intervention was less frequent in the heater prohc group.
Hui ,md co-workers (8) J1d a randomized comparative study llf lasL' r phnwcoagulaunn, heater prohe and bipo lnr e lcctrou>agulauon int reatme nt nf acti vely hlccdmg ukcr:..There was no Clmtrol group 111 this :,tudy anJ the authors found the three treatment groups similar with regard l\l ratl' of reblccding, duration of hospital stay anJ prnpnnion of emergcnq• surgery required.They stated that they prl'• fcr red the bi po lar e lec trocoagulation and hemer prohe over the YA Ci laser because the fmmer rwo me less cxpen-sive (although the difference was nrn sign ificant) and rehleeding 111 the hearer probe group was twice thm of the laser and clcunicoagubtion group.

TECHNIQUE
Treatment parameters: There has hecn rene\,ed focus regardmg the amount of power and pulse durarnlll for the d1fkrenr thermal devices.lnirial lv ~lPEl' pnwer was in the range of 50 W with I to 2 s pube,,.Work by Jensen and Laine ( 3,4,9) suggests that the depth oft issue effect (and poss1hly successful thernpy) can be afteued hy power and pu be durat 11 ll1 settmgs.They recommend 2 5 W and con tact umcs of lO ro 14 s.With thL• he,1ter probe.30 J 1s ,1dv ised and um tact limes of 8 rn l Os required.The d1..•p1 h of injury can be increased hy keeping the prnhe proximate to the treated area.With a Y A(J laser, the standard seuing wou ld ht• 70 to 80 Wfor 0. 3 to 0.5 s.T1:,sue effects will also vary wi th dist,1nce from I he laser fihrc tn lls:,ue bct,iuse 1..•ncrgy density will vary wnh distance (hecause the ht•nm is di, ergent) 111 this mincontact med1lld.
If a spurrang ,lrlcry is treated wnh .icontact de,•ice (MPEC or heater pmbc ), tht• device should he applied direcrly tn the :,pun of blood fo r a direct ct1apli\'1..' effect.The Y AC laser\ beam i, aimed al and around the spurt111g artery lo creme some edema frllm the thermal 111 J llr)'.
Thcrt• is nll Lllnsensus on the he,t methlld for Lreating ,1 v1~ihle vcs~el.The m,lJ<lnty of experts hcl icl'e that trl'ating ci rcumfcrenuall y around thl' ves:,,cl before lrl•aring tls centre adds a safct y margm of mcreascd edema and vaM>eonst riclillll of thl' bleeding vessel.A minom y op mum bcl1c,•1..'s th,it direct pressure to the vessel as eftcct ivl' and minimizes injury tn surroundmg tissue.Thermal therapy for bleeding indicated.I ltiwever, 1( treatment is to be carried out, there arc two apprllac hes.Preinjecti11n aniund the c lnt with adrenaline \\ ill cause vasllconsmclllln oft he underlying vessel and the edema, and bmh consLrict the vessel and limn a 1m1und which will c,•1cl the c lot. Altern.1tively.a twll-channcl sCllpe cou ld he used with a grasping forLcps placed through lll1e of the l hanncls tn grah the clot.If hlced ing ensue,, a thernpcunc device pl,iced through the ,cumd c hannel Cllu ld be poised for therapy.

UNIQUE SITUATIONS
A lthough thL• porrnbilary ot the Ml'Ll • and heater probe make them dcs1rahle for trcaung pepll1.. ulcers and should be Cllnsidcred as the first line of rhernrn l t herapy, hccause the laser can he used 111 a noncontact fashio n. penetrate more deeply, treat a hruader area ,111d more rapidly treat mu luplc lesions, there arc unique s1t uat1rn1s in whi ch laser t herapy i:, preferable tn MPH ,ind heater prnbc.These cond1tams include watermelon ,tomach, multiple angmdy~plasia a nd radiauon pnictiris.In add1rnin, hccause penL'lran on with the Y AC, laser 1~ decpn, ll is more cffcctl\'C than the cont ,1ct device~ for treatmg tumours lif the g,1-.,tn1111te~tinaltract wh ich hlced and for which endoscopic thernpy 1, deemed appropriate.