Us­ing blood-pres­sure cuff in new way could limit heart at­tack dam­age: study

Cape Breton Post - - NEWS -

TORONTO (CP) — Vir­tu­ally every­one has had their blood pres­sure mea­sured with a pumped-up cuff en­cir­cling their up­per arm. But it turns out that this com­mon­place med­i­cal de­vice could one day have an­other crit­i­cal use — re­duc­ing the amount of dam­age from a heart at­tack, re­searchers say.

In a study of more than 250 Dan­ish adults ex­pe­ri­enc­ing a heart at­tack, Cana­dian-led sci­en­tists used a blood pres­sure cuff to in­ter­mit­tently stop blood flow in the arm, a process that be­gins while a pa­tient is be­ing trans­ported to hospi­tal by am­bu­lance.

Called “re­mote is­chemic pre­con­di­tion­ing,” the pro­ce­dure de­vel­oped by Toronto’s Hospi­tal for Sick Chil­dren was found to sig­nif­i­cantly limit the amount of dam­age to the heart mus­cle caused by a block­age in a car­diac blood ves­sel.

Is­chemic pre­con­di­tion­ing in­volves us­ing the de­vice to in­ter­rupt blood flow in the arm, off and on over a pe­riod of 35 to 40 min­utes: the cuff is in­flated for five min­utes, then de­flated for five min­utes, with the pro­ce­dure be­ing re­peated con­sec­u­tively four times.

Once at the hospi­tal, the pa­tient re­ceives rou­tine heart at­tack treat­ment, in­clud­ing car­diac an­gio­plasty. Pre­con­di­tion­ing us­ing the cuff may still be go­ing on through­out this pro­ce­dure, which uses a tiny in­flat­able bal­loon to open up nar­rowed or blocked blood ves­sels to the heart.

Re­searchers, whose pa­per ap­pears in to­day’s is­sue of The Lancet, found that those heart at­tack pa­tients ran­domly as­signed to have pre­con­di­tion­ing had an over­all re­duc­tion in heart mus­cle dam­age of 30 per cent, com­pared to those not treated with the cuff.

In those hav­ing the largest, typ­i­cally most dev­as­tat­ing, heart at­tacks, the amount of dam­age was cut by about 50 per cent, said se­nior co-au­thor Dr. An­drew Redington, head of car­di­ol­ogy at Sick Kids Hospi­tal.

“And we know, of course, that the big­ger the heart at­tack you have, the more likely you are to die and the more likely you are to have sub­se­quent symp­toms of heart fail­ure and all the bad things that hav­ing a heart at­tack pre­dicts,” Redington said in an in­ter­view Thurs­day. “So any re­duc­tion in heart at­tack size is ben­e­fi­cial and a 50 per cent re­duc­tion is re­ally quite re­mark­able.”

Redington, who co-or­di­nated the joint study by re­searchers in Toronto, Den­mark and Eng­land, said the idea of is­chemic pre­con­di­tion­ing first arose about 25 years ago, pri­mar­ily be­cause of work in lab­o­ra­tory an­i­mals.

Sci­en­tists found that if tis­sues are starved of blood in an in­ter­mit­tent man­ner, it seems to pre­pare them for a more pro­longed in­ter­rup­tion in blood and oxy­gen sup­ply, he said, ex­plain­ing that halt­ing flow re­leases a sub­stance into the blood that “cir­cu­lates and bathes all the or­gans, not just the heart, to pro­tect them.”

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