PRE­VEN­TION OF CORO­NARY ARTERY DIS­EASE

New di­ag­nos­tic tests to de­tect heart at­tack risk in those with no his­tory

Great Health Guide - - CONTENTS - Dr War­rick Bishop

IN the ar­ti­cle in the last issue of Great Health GuideTM, I dis­cussed meth­ods of Gaug­ing Your Heart At­tack Risk. In this ar­ti­cle, I dis­cuss new meth­ods with tests specif­i­cally used to di­ag­nose and thus ini­ti­ate treat­ment prior to the first heart at­tack. This is called pri­mary pre­ven­tion of coro­nary artery dis­ease. Sec­ondary pre­ven­tion, i.e. treat­ing the con­se­quences of coro­nary artery dis­ease, is also dis­cussed.

1. PRI­MARY PRE­VEN­TION OF CORO­NARY ARTERY DIS­EASE.

Pri­mary pre­ven­tion of coro­nary artery dis­ease in­volves pa­tients who have ei­ther not yet had a prob­lem or who have not com­plained of any symp­toms of coro­nary artery dis­ease. While these peo­ple may be at high risk be­cause of a range of in­di­ca­tors, such as el­e­vated choles­terol lev­els, high blood pressure, di­a­betes or smok­ing, they do not dis­play any symp­toms nor have they been iden­ti­fied as hav­ing a heart prob­lem. Nev­er­the­less, it is im­por­tant to re­alise that these pa­tients may carry an in­creased risk. The treat­ment for that risk, prior to an event, is called pri­mary pre­ven­tion. The prob­lem is that best prac­tice in pri­mary pre­ven­tion of coro­nary artery dis­ease is more dif­fi­cult be­cause it is not well de­fined at present.

2. SEC­ONDARY PRE­VEN­TION FOL­LOW­ING A HEART AT­TACK.

Tra­di­tional ap­proaches to coro­nary artery dis­ease tend to fo­cus on sec­ondary pre­ven­tion or on treat­ing the con­se­quences of coro­nary artery dis­ease. The symp­toms of coro­nary artery dis­ease in­clude short­ness of breath, chest pain on ex­er­tion or acute coro­nary syn­drome, which is a set of symp­toms that arise due to de­creased blood flow in the coro­nary ar­ter­ies. There is no ques­tion that sec­ondary pre­ven­tion is ben­e­fi­cial in re­duc­ing the rate of re­cur­rence of a sub­se­quent heart event. The data around sec­ondary pre­ven­tion of coro­nary artery dis­ease is very strong and I do not be­lieve there is any need for al­ter­na­tive in­ter­pre­ta­tions or strate­gies regarding sec­ondary pre­ven­tion at this stage.

My ob­jec­tive in my own prac­tice is to iden­tify ways to avoid the first heart event.

I be­lieve that cur­rent pri­mary pre­ven­tion prac­tice has scope for sig­nif­i­cant reeval­u­a­tion, par­tic­u­larly in our ap­proach to risk assess­ment of in­di­vid­u­als be­fore they even have a prob­lem. In fact, to me, pre­vent­ing the chest pain or the heart at­tack in the first place is the Holy Grail of pre­ven­ta­tive car­di­ol­ogy.

When dis­cussing risk fac­tor assess­ment in coro­nary artery dis­ease, it is ex­tremely im­por­tant to be clear about the dif­fer­ence be­tween as­so­ci­a­tion and cau­sa­tion. Reg­u­larly, I need to tell pa­tients that they have choles­terol build-up in their ar­ter­ies.

In­vari­ably I re­ceive the re­ply,

• ‘But Doc­tor, my choles­terol is fine’.

• ‘But Doc­tor, I ex­er­cise reg­u­larly’.

• ‘But Doc­tor, I eat healthy food and keep my weight down’.

• ‘But Doc­tor, I don’t smoke’.

When we eval­u­ate the risk of an in­di­vid­ual in pri­mary pre­ven­tion of coro­nary artery dis­ease, we use as­so­ci­a­tions that have been demon­strated in pop­u­la­tion stud­ies. This presents an in­her­ent prob­lem be­cause risk may be low for the pop­u­la­tion, but it is 100 per­cent for the

Heart imag­ing provides clear information about the state of an in­di­vid­ual's heart.

in­di­vid­ual who then goes on to have an event. While in­di­vid­ual screen­ing us­ing stress-test­ing does have some merit, it will only iden­tify prob­lems too late in the process of choles­terol build-up in the ar­ter­ies.

One of the key tools that I use in pri­mary pre­ven­tion is the lat­est tech­nol­ogy avail­able to scan the heart. Heart imag­ing provides clear information about the state of an in­di­vid­ual’s heart. It is used to in­form a man­age­ment strat­egy based on ex­actly what was seen to be hap­pen­ing in the ar­ter­ies, rather than a best guess based on a pop­u­la­tion­based prob­a­bil­ity of what might be go­ing on.

Car­diac CT imag­ing will lead to a con­clu­sion that the fea­tures ob­served on the scan are ei­ther low, in­ter­me­di­ate or high-risk fea­tures and this information can then be used against tra­di­tional risk vari­ables to fa­cil­i­tate the most ac­cu­rate com­pu­ta­tion of an in­di­vid­ual pa­tient’s risk. By com­bin­ing the car­diac CT imag­ing and risk information of the pa­tient, I be­lieve that the best-in­formed man­age­ment strat­egy for the pri­mary pre­ven­tion of coro­nary artery dis­ease in an in­di­vid­ual pa­tient, can be achieved.

Dr War­rick Bishop is a car­di­ol­o­gist, with spe­cial in­ter­est in car­dio­vas­cu­lar dis­ease pre­ven­tion in­cor­po­rat­ing imag­ing, lipids and lifestyle. He is author of the book ‘Have You Planned Your Heart At­tack?’, writ­ten for pa­tients and doc­tors about how to live in­ten­tion­ally to re­duce car­dio­vas­cu­lar risk and save lives! Dr Bishop can be con­tacted via web­site.

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