Surgery for swing­ing-door heart valves has is­sues

The Guardian (Charlottetown) - - HEALTH - Dr. Gif­ford Jones Dr. W. Gif­ford-Jones is a syn­di­cated colum­nist whose med­i­cal col­umn ap­pears in The Guardian ev­ery Tues­day. Check out his web­site, www.docgiff.com, which pro­vides easy ac­cess to past col­umns and med­i­cal tips. For com­ments, read­ers are inv

Mi­tral valve surgery can best be de­scribed by com­par­i­son to the swing­ing saloon door in old western movies as it demon­strates what can go wrong with the heart’s valves and what sur­gi­cal pro­ce­dure is needed to cor­rect mi­tral valve pro­lapse (MVP).

To get a first-hand view of this pro­ce­dure, I watched Dr. Tirone David, one the world’s great car­diac sur­geons, per­form the op­er­a­tion at Toronto Gen­eral Hos­pi­tal.

The mi­tral valve sep­a­rates the two left cham­bers of the heart. Each time the heart beats the valves swing open, like the doors of a western saloon. But af­ter open­ing they close firmly again while the heart pumps blood to the body.

The prob­lem is that swing­ing doors of sa­loons of­ten de­velop loose rusty hinges that don’t close well. The mi­tral valve has the same trou­ble when the tough para­chute-like cords that at­tach the valves to the heart’s mus­cle be­come too loose. When this hap­pens some ejected blood falls back into the heart’s cham­ber fol­low­ing ev­ery beat. This places ex­tra bur­den on the heart’s mus­cle.

If you’re di­ag­nosed with this con­di­tion, don’t panic. You’re far from the end of the road. Prior to the use of echocar­dio­grams (ul­tra­sound of the heart), doc­tors be­lieved MVP was present in 17 per cent of women and five per cent of men. Now we know it’s less com­mon, af­fect­ing about 2.4 per cent of both sexes. But, ac­cord­ing to a re­port from Johns Hop­kins Univer­sity, about 25 per cent of Amer­i­cans older than age 55 have some de­gree of MVP. It’s now be­lieved that, in ad­di­tion to ag­ing, ge­net­ics also plays a role in who de­vel­ops this con­di­tion.

How mi­tral valve pro­lapse is treated de­pends on sev­eral fac­tors. The great ma­jor­ity of pa­tients with MVP have no idea it is present and nor­mally do not need surgery.

Some pa­tients com­plain of short­ness of breath, pal­pi­ta­tions and fa­tigue. But peo­ple with­out MVP can ex­pe­ri­ence sim­i­lar symp­toms. What of­ten hap­pens is these symp­toms oc­cur af­ter the di­ag­no­sis, trig­ger­ing anx­i­ety.

David says that sev­eral fac­tors must be con­sid­ered be­fore de­cid­ing mi­tral surgery is needed. One of the most im­por­tant is the sever­ity of the pro­lapse and what af­fect it’s hav­ing on the heart’s mus­cle.

There’s an old say­ing that, “A stitch in time saves nine”. In mild cases of MVP, there’s no point in ex­pos­ing pa­tients pre­ma­turely to the risk of surgery. But it also makes no sense to wait un­til ei­ther the pa­tient’s symp­toms are se­vere or the mus­cles of the heart are fail­ing from ex­tra stress.

Mi­tral valve surgery is not just for in­com­pe­tent valves. It’s also per­formed when the mi­tral valve be­comes thick­ened and rigid from ag­ing and the open­ing be­comes as small as a pen­cil. The ex­tra work of push­ing blood through such a tiny open­ing can also cause heart fail­ure.

Pa­tients with these con­di­tions of­ten have heart mur­murs that can be de­tected by a stetho­scope. But an echocar­dio­gram of the heart will de­ter­mine their sever­ity and help to gauge whether the con­di­tion is wors­en­ing.

In re­cent years there’s been tremen­dous ad­vance­ments in sur­gi­cal tech­nique for the treat­ment of MVP or steno­sis.

The morn­ing I watched David op­er­ate, the pa­tient’s chest was opened in the same way as a by­pass op­er­a­tion. This pa­tient suf­fered from se­vere mi­tral steno­sis and re­quired a to­tally new valve.

The ma­jor­ity of cases per­formed to­day try to save the old valve. For in­stance, it is of­ten pos­si­ble to shorten the para­chute-like cords which re­store the valves to their nor­mal po­si­tion. The ad­van­tage to us­ing the pa­tient’s own tis­sue is that there is no chance of its rejection by the body.

In other cases, min­i­mal in­va­sive surgery can be done by work­ing through the femoral artery, the blood ves­sel at the top of the leg. A new valve is guided through the artery us­ing a spe­cial catheter tube un­til it reaches the mi­tral valve lo­ca­tion and is in­serted.

David says there’s no age limit for mi­tral valve surgery as long as the pa­tient has no other prob­lems that would in­crease the risk. His old­est mi­tral valve pa­tient was 95 years of age.

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