Aortic insufficiency

By

CHA~S

A. H U F N A G E L

" of aortic insu~eien~r" as a cLinical a n d pathologic entity g r e a t change. A reappraisal of the etiology has demonstrated t h a t a l t h o u g h r h e u m a t i c disease and its sequelae are a major cause of this lesion either in its p u r e form or in association w i t h some d e g r e e of aor~c stenosis, t h e r e are m a n y other causes of this lesion w h i c h are s u ~ c i e n t l y common as to l~equire serious considera~on in t h e differential etiological diagnosis_ Of even greater importance is the recognition that these varied causative diseases p r o d u c e different anatomical d e r a n g e m e n t s of the valvular mechanism w h i c h lead to the production of r e g u r g i t a t i o n . It is only through an u n d e r s t a n d i n g o f the mechanisms of the normal function of the valve a n d G~ose aberrations from normal p r o d u c e d b y the v a r y i n g causative agents, t h a t one can intelligently follow the progression of the disease in its natural history. This to develop the most rational and t h e safest method ptwsiologic amelioration of the hemodyn,~mie problems w h i c h result from the different mechanical alterations. A brief survey of t h e etiology of aortic regurgitation, and the most common a n a t o m i c a l d e r a n g e m e n t s p r o d u c e d b y the causative processes is therefore an essential preh~de to a discussion of the metliods of treatment. A. Aortic insufficiency of congenital origin m a y b e associated with a hi-

s u b a c u t e bacterial endocarditis superimposed upon the bicuspid valve. Congenital fenes~ations of leaflets of the aortic valve m a y b e a n o t h e r cause of openings in such a valve tend to be at the base of

region of t h e septal defect which produces d o w n w a r d and o u t w a r d displacem e n t of a cusp: This drops t h e edge of the revolved l e a f l e t b e l o w i t s fellows a n d allows leakage. B. D i r e c t d a m a g e to the aortic valve m a y b e p r o d u c e d b y direct laceration of t h e aortic valve with a sh,-a~ i n s t r u m e n t or missile. W h e n p r o d u c e d by sharp instruments i n t r o d u c e d from the left a n d anteriorly, the r i g h t ventricle is f r e q u e n t l y entered first and in such cases there m a y be an associated transient or persistent in tricular defect. I n d i r e c t compre,~sion w i t h o u t Thi~ w o r k has been st~pported in part b• t h e grant-in-aid f r o m t h e National H e a r t I n s t i t u t e o~ t h e National Ir~tltutes o] Health o] t h e U n i t e d States P u b l i c H e a l t h Service

(1t--~9Z4) From the D.C.

grit o f Surgery,

o w n University M e d i c a l Center, W a s h i n g t o n ,

278

AORTIC

~SUFFICmNCY

279

p e r i e ~ a ~ o n o f ~ e t h o r a x m a y p r o d u c e r u p t u r e o f o n e o r m o r e leaflets o f t h e valve a n d occasionally in such instances a c o n c o m i t a n t v e n t r i c u l a r d e f e c t m a y also o c c u r . S u c h i n j u r i e s h a v e b e e n s e e n in a s s o c i a t i o n w i t h u n d e r w a t e r b l a s t i n j t u ~ as w e l l as c h e s t c o m p r e s s i o n f r o m a v a r i e t y o f s o u r c e s w i t h o u t imirlexsion.

C. S y p h i l i s has l o n g b e e n c o n s i d e r e d a m a j o r s o u r c e o f p u r e a o r t i c insu~qlciency; however, vdth early and more adequate therapy there has been a m a r k e d d e c r e a s e i n t h e i n c i d e n c e o f tile I a t e folaaas o f t i l e d i s e a s e . L u e s has b e e n a r e l a t i v e l y u n c o m m o n c a u s a t i v e a g e n t in o u r series. T h e p a t h o l o g i c l e s i o n is a bAghly v a r i a b l e o n e . T h i s m a y r a n g e f r o m a s i m p l e s e p a r a t i o n o f t h e c o m m i s s u r e s w i t h tl , c k e m n g o f t h e leaflets a n d a m a r k e d d e f o r m i t y o f a s i n g l e leaflet, o r in o t h e r e a s e s t o a m a r k e d t h i c k e n i n g a n d s h o r t e n i n g o f all leaflets w i t h e s s e n t i a l l y a t o t a l v a l v u l a r d e s t r u c t i o n . I n s o m e c a s e s m a r k e d d i l a t a ~ o n of t h e a o r t i c r o o t m a y b e p r e s e n t in a s s o c i a t i o n wiLh v a r y i n g d e g r e e s of valvular involvement. D. R h e u m a t i c h e a ~ d i s e a s e p r e s e n t s t h e m o s t w i d e l y v a r i a b l e a n a t o m i c lesions. I n t h e p u r e f o ~ of aortic insu~ciency fusion of the commissures is m i n i m a l to a b s e n t . F r e q u e n t l y , t h e val~/e leaflets a p p e a r t o b e t h i n n e r t h a n n o r m a l i n s o m e a r e a s , w h i l e flee e d g e s o f t h e c u s p s a r e t h i c k e n e d a n d r o i l e d . I n o t h e r s t h e t h i c k e n i n g o f t i l e c u s p s is a r e l a t i v e l y s m a l l c o m p o n e n t w h i l e p r o I a p s e o f t h e c u s p d u e to s t r e t ~ l i n g o f t h e s u b s t a n c e is t h e d o m i n a n t p r o b l e m . I n ~ n a e c a s e s o n e or m o r e c u s p s m a y b e r e l a t i v e l y n o r m a l ; b u t in t h e m a j e s t y a l l c u s p s axe i n v o l v e d to v a r y i n g d e g r e e s . I n s o m e i n s t a n c e s f u s i o n o f t h e two c u s p s h a s o c c u r r e d w i t h p a r t i a l o r t o t a l d e s t T u e t i o n o f o n e or t w o e o m m i s s u r e s . T h i s r e s u l t s i n i n c r e a s e d l e n g t h o f file l e a d i n g e d g e s o f t h e leaflets a n d p r o d u c e s p r o l a p s e . D i l a t a t i o n o f t h e a n n u l u s m a y p r o d u c e a o r t i c v a l v e l e a k a g e w i t h n o c h a n g e i n t h e v a l v u l a r c o n f i g u r a t i o n , o r m a y b e associated with any of the other types of valvular deformity. \X,r h e n s t e n o s i s is a l s o p r e s e n t t h e v a r i a t i o n s a r e still m o v e c o m p l e x . C a l cification m a y v a r y f r o m severe to none. F n s i o n of t h e leaflets w i t h e x t r e m e t h i c k e n i n g a n d f i b r o t i e elnanges a n d s h o r t e n i n g r e d u c e s Che e f f e c t i v e v a l v e s ~ e b e t w e e n t h e c~asp e d g e s . W h e n c a l c i f i c a t i o n is p r e s e n t it m a y o c c u r p r i m a r i l y a l o n g t h e l i n e o f i n s e r t i o n o f tl~e l e a f l e t s i n t o t h e a e r i e a n n u l u s w i t h r ~ s u l t i n g d e c r e a s e d m o b i l i t y o f t h e b a s e o f t h e cusps, o r i t m a y b e m o r e extensive invol~ng the leafle~ themselves. ~e fo~ation of calcifie s t r u ~ x~q'~ich h o l d t h e v a l v e in a r e l a t i v e l y c l o s e d p o s i t i o n m a y a l s o b e s e e n . S u c h a b u t t r e s s i n g e f f e c t m a y o c c u r as t h e r e s u l t o f c a l c i u m d e p o s i t s o n t h e a o r t i c s~ace of the valve, or these may be present on the ventricular surface, e x t e n d i n g d o w n w a r d to t h e m u s c l e of t h e l e f t v e n t r i c l e . "When calcificat i o n is p r e s e n t it m a y b e r e l a t i v e l y s u p e r f i c i a l a n d r e a d i l y r e m o v a b l e , o r it m a y extend t h r o u g h o u t t h e valwalar s u b s t a n c e replacing the valw.dar tissue with sand-like concretions which occupy the space beneath the endothelialized su . T h e s e m a r k e d p a t h o l o g i c c h a n g e s in t h e w f l v u l a r s t r u c t u r e g i v e r i s e to h i g h l y v a r i a b l e p r o b l e m s w h i c h m u s t b e i n d i v i d u a l l y a s s a y e d in t e r m s o f met,hods of c~rrect/on. E . B a c t e r i a l e n d o c a r d i t i s is a n a d d i t i o n a l i m p o r t a n t c a u s e of a o r H c insuffic i e n c y . T h e p r e s e n t r e l a t i v e l y hdgh r a t e o f b a c t e r l o l o g i e c u r e o f t h i s l e s i o n

280

Cr~RLES A. I*IUFNAGEL

produced a group of patients who following the eradication of the active b a c t e r i a l p r o c e s s h a v e v a E d n g d e g r e e s o f a o r t i c i n s u ~ c i e n c y as a r e s i d u a l . A c u t e e n d o e a r d i t £ s c a n l e a d t o t]ae s u d d e n d e v e l o p m e n t o f a n a o r t i c l e s i o n of a n e x t r e m e l y s e v e r e f o r m . S u b a c u t e b a c t e r i a l e n d o e a r d i t i s m a y also p r o d u c e r e g u r g i t a t i o n e a r l y i n t h e c o u r s e Of t h e d i s e a s e , o r t h i s m a y n o t "o e m a n i lest until a considerable period after evidence of effective control of the b a c t e r i a l p r o c e s s a n d w h e n t h e p a t i e n t a p p e a r s to b e d o i n g w e l l . T h i s l a t e d e : v d o p m e n t o f a o r t i c r e g u r g i t a t i o n is u s u a l l y a s s o c i a t e d w i t h s c a r r i n g a n d s h o r t e n i n g o f t h e leaflet, a l t h o u g h s o m e t ~ e s i t m a y r e s u l t f r o m p e r f o r a t i o n of a previously damaged valve area. ObsemJation of a considerable number :onclusion that while the active visible l o c a l i z e d to o n e o r t w o c u s p s t h e r e is u s u a l l y se i n v o l v e m e n t , a n d t h e d a m a g e to v a l v u l a r ~ s s u e s is m u c h m o r e w i d e s p r e a d t h a n m a y be e v i d e n t on a casual examination. T h e r a p i d o n s e t o f s e v e r e a o r t i c i n s u l ~ c i e n q y is u s u a l l y a s s o c i a t e d w i t h a n o m i n o u s prognosis unless the h e m o d y n a m i e lesion can b e corrected, F. A n e u r y s m s o f t h e s i n u s o f V a l s a l v a h a v e b e e n m o s t f r e q u e n t l y s e e n a f t e r produce fistulae from the aorta into the right tricle, '~,Vhen t h e o p e n i n g is s m a l l t h e l e s i o n m a y be p r e s e n t for a c o n s i d e r a b l e p e r i o d of t i m e b e f o r e m a j o r s y m p t o m s develol). W h e n t h e f i s t u l a is l a r g e r t h e s i g n s o f ~ g h t s i d e d f a i l u r e m a v b e m a n i f e s t t o t h e s e a r e u s u a l l y s e e n as a n i p p l e - l i k e p r o lar or ventricular chambers, and the area of rupture can usually be visualized. O. D i s s e c t i n g a n e u r y s m h a s b e e n a w e l l recoffnizedo p a t h o l o g i c e n t i t y b u t o n l y r e c e n t l y h a s t h e c h m c a l d i a g n o s i s o f t h e p r o b l e m b e c o m e c o m m o n . It~ association ~qth ao~c insu~cienc T however has not been wel| documented. e x c e p t in t h e p a s t t w o y e a r s . D i s s e c t i n g a n e u r v s m m a y p r o d u c e i n s u f f i c i e n c y b v d i l a t a ~ o n o f t h e a o N c a n n u l u s o r b y d e t a d n m e n t o f o n e o r m o r e leafle(s from their eommissural zones on the aerie wall which permits 9relapse. Corona~ e s m a y o r m a y n o t b e d i r e c t l y i n v o l v e d i n t h e d£sseetion. Fortunately, these vessels are usually spared. H: Idiopa~,aie d i l a t a t i o n o f t h e a o r t i c r o o t m a y b e s e e n w b t h o u t ~ o - , v n a n t e cedent cause. The development of generalized enlargement of the aortic root prevents, adequate dosure of the aortic valve by increasing the diameter of t h e a s c e n d i n g a o r ~ at t h e l e v e l o f t h e c o m m l . s u r a l i n s e r t i o n s . W h e n t h e d i a m e t e r is in-creased t h e l e n g t h o f t h e l e a ~ e t s is i n s u f f i c i e n t to e f f e c t v a l v e closure in t h e central zones. T h i s c o n s i d e r a t i o n o f t h e v a r i e d c a u s a t i v e f a c t o r s in t h e p r o d u c ~ o n o f t h e sin~|e hemod-cnamic lesion of aortic i n s u m c i e n c y e m p h a s i z e s the n e e d for a b r o a d n n d e r s t a n d i n K o f t h e p r o b l e m . I t f u r t h e r d e m o n s t r a t e s t h a t m a n y diff e r e n t f a c t o r s m a y b e i n v o l v e d i n t h e pro.~nosis o f w h a t a p p e a r d i n i e a l l v t o b e r e l a t i v e l y s l m l l a r a r t m leaks. T h e s e f-_qctors i n c l u d e r a o i d i t v o f o n s e t . m a D i t x l d e o f t h e i n s u m c i e n c v , t h e d e g r e e o f c o r o n a r y a r t e r y i n v o l v e m e n t in t e r m s o f D a t e n c v o f t h e vessels a n d t h e m a ~ i h z d e o f t h e m u s c l e m a s s . Ot2ner f a c t o r s x~;nich d i r e c t l y a f f e c t t h e o v e r a l l p i e h , r e a r e t h e d e ~ r e e o f i m r ~ a i r m e n t o f mb,o e a r d i a l c o n t r a c t i l i t y b v s u c h f a c t o r s as e a r d i t i s , i n f e c t i o n , r h e a , m a t i c *

Q

O

*

AOI:IT1C I N S U F F I C I E N C Y

_013I

d ~ e a s o a n d m e t a b o l i c f a c t o r s w i t h i n t h e m u s c l e itself. C h a n g e s w h i c h m a y b e p r e s e n t i n t h e c o n d u c t i o n s y s t e m also h a v e a d e f i n i t e r o l e in t h e p r o g n o s i s . T h e u n d e r l y i n g b a s i s o f t h e s e c o n d u c t i o n c h a n g e s is p o o r l y u n d e r s t o o c t b u t they a p p e a r to p l a y an i m p o r t a n t role in the s u d d e n d e a t h associated w i t h venta'icular f i b r i l l a t i o n . T h e s e c o n s i d e r a t i o n s h a v e l e d to t h e d e v e l o p m e n t o f t h e t e c h n i c s fox- t h e correction of t h e various lesions b a s e d u p o n t h e specific a n a t o m i c a l derangem e n t s w h i c h m a y b e p r e s e n t in t h e p a r t i c u l a r s i t u a t i o n . B a s i c a l l y , t h e s e corr e c t i v e t e c h n i c s c a n b e d i v i d e d i n t o t h o s e w h i c h a r e d i r e c t e d t o w a r d t h e correction of those lesions w h i c h p r i m a r i l y involve a b n o r m a l i t i e s of t h e aortic leaflets a n d t h o s e w h i c h i n v o l v e t h e a o r t i c r o o t w i t h r e l a t i v e l y n o r m a l leaflets, combinations of these two, and finally those lesions which involve communicarson b e t w e e n fl~e a o r t i c r o o t a n d o n e of t h e c a r d i a c c h a m b e r s w i t h o r w i t h -~ o u t dia-ect i n v o l v e m e n t of v a l v u l a r s u b s t a n c e . D u r i n g t h e p a s t five y e a r s w e leave d e v e l o p e d a series o f p r o s t h e t i c a o r t i c v a l v u l a r r e p l a c e m e n t s o f i n c r e a s ing d e g r e e s o f s o p h i s t i c a t i o n . F o r flae p a s t t w o ),ears t h e p l a c e m e n t o f t h e prosthetic aortic valves has b e e n an a c c o m p l i s h e d fact in patients. T h e valve c m T e n t l y e m p l o y e d is o f a l e a f l e t t y p e m a d e w i t h a d a c r o n c l o t h b a s e i m pregnated with silicone rubber under high pressure in a shape which essentially duplicates the normal aortic valve configuration. The cusps may be u s e d i n d i v i d u a l l y o r as a g r o u p o f t h r e e u n i t e d at t h e i r c m n m i s s u r e s (fig. 1 ) . T h e s e leaflets e_re e x t r e m e l y flexible mad h a v e a reflex e d g e w h i c h p e n n i t s Proslhesls

remn~n*

__(

It. v e n t r i c u l o r covity

Fig. leallets sutures sealing

i,::: 0

-~-::~:

: ::~,

::"

="

l . ~ T h r e e cusps united t o form a total valve r e p l a c e m e n t . T h e d i s e a s e d have been excised. T h e ~rst c o m m i s s u r a I stitch h a s been placed. Otller are placed in the aortic a m m h t s a t the base of the CUSp, Note tlie self edges of the leaflets.

_082

CI~IABLES A . H U F N A G E L

s e i r - s e a n n g so t h a t l e a k a g e d o e s n o t o c c u r in b e t w e e n t h e s u t u r e s e v e n i m a n e d i a t e l y a f t e r t h e v a l v e is p l a c e d . T h e reflex e d g e is n o t i m p r e g n a t e d w i t h t h e silicone r u b b e r so t h a t h e a l i n g c a n o c c u r w i t h t h e a o r t i c w a l l a t this p o i n t . T i s s u e d o e s n o t g r o w i n t o t h a t p o s e n of the valve which moves d u e to tile i m p r e g n a t i o n w i t h silicone r u b b e r . A n y i n g r o w t h o f t i s s u e into this m o v i n g v a l v e a r e a t e n d s o v e r a p e r i o d o f t i m e to s t i f f e n t h e c u s p a n d d e c r e a s e its m o b i l i t y . V.Je b e l i e v e tbAs to b e h i g h l y u n d e s i r a b l e a n d is p r e v e n t e d b y this t y p e o f p r o s t h e s i s . T h e s e leaflets a r e e x t r e m e l y flexible, a n d r e s u l t in n o d e g r e e o f o b s t r u c t i o n to a o r t i c o u t f l o w . T h e y a r e s u t u r e d i n t o p l a c e in t h e a o r t i c a n n u l u s w h i c h is t h e f i r m e s t p o i n t of fixation in t h e a o r t i c w a l l . T h e artLflcial v a l v ~ a r e so d e s i g n e d t h a t t h e y f o l l o w this n o r m a l cmnti g u r a t m n . T h e y h a v e b e e n c o n s t a ' u e t e d in v a r y i n g sizes t o fit a o r t i c r o o t s o f all t y p e s . I t h a s b e c o m e a p p a r e n t t h a t in s o m e p a t i e n t s all t h r e e leaflets a r e n o t t h e s a m e size. T h u s , t h e c u s p s w h i c h a r e i n s e r t e d m u s t b e v a r i e d to fit the pmrticular situation encountered. T h e a p p r o a c h to t h e a o r t i c r o o t is m a d e tlh-ough a m i d l i n e s t e r n o t o r n y a n d after the usual preparations for cardiopuhnonary bypass, the ascending aorta is o c c l u d e d j u s t b e l o w t h e i n n o m i n a t e a r t e r y . T h e h e a r t is t h e n p u t i n t o a r r e s t f o r p e r i o d s u p to t w o h o u r s . I n this g r o u p of p a t i e n t s local c a r d i a c c o o l i n g h a s b e e n u s e d in o v e r 150 a o r t i c r e p a i r s , i n this g r o u p of p a t i e n t s t h e r e h a v e b e e n o n l y t~vo i n s t a n c e s in w h i c h t h e r e s u m p t i o n of a n o r m a l s i n u s r h y t h m c o u l d n o t 1~ o b t a i n e d . S i n c e this g r o u p i n c l u d e s a l a r g e p r o p o r t i o n o f p a t i e n t s w i t h fro" a d v a n c e d d i s e a s e , w e b e l i e v e t h i s m e t h o d o f c a r d i a c a r r e s t to b e e x t r e m e l y satisfactory when properly employed. After the induction of cardiac arrest t h e h e a r t is m a i n t a i n e d in t h e c o o l e d s t a t e u n t i l t h e i n t r a - a o r t i c p o s e n of t h e p r o c e d u r e is c o m p l e t e a n d t h e a o r t o t o m y is a l m o s t c l o s e d . T h e h e a r t is t h e n r e f i l l e d w i t h b l o o d a n d all a i r is e v a c u a t e d f r o m t h e l e f t side, T h e final c l o s u r e o f t h e a o r t a is t h e n m a d e , a n d t h e c o r o n a r y f l o w is r e i n s t i t u t e d w h e n t h e a o r t i c c r o s s c l a m p is r e m o v e d . S i n c e m o s t h e a r t s h a v e p e r i o d s of v e n t r i c u l a r fibrillation following their r e w a r m i n g , electrical defibrillation has b e e n necess a r y to r e s t o r e n o r m a l s i n u s r h y t h m . W i t h i n c r e a s i n g e x p e r i e n c e it h a s b e e n o u r f e e l i n g t h a t t h e m a j o r i t y o f p a t i e n t s w i t h s e v e r e a o r t i c Lnsut~eieney r e quire the replacement of their aortic valve. We have used partial replacement w i t h g o o d r e s u l t s , b u t f e e l t h a t t2nAs s h o u l d b e r e s t r i c t e d to s e l e c t e d i n s t a n c e s s~-aco b r e a k d o w n o f t h e r e m a i n i n g v a l v u l a r t i s s u e h a s o c c u r r e d in t h e m o n t h s f o l l o w i n g o p e r a t i o n in s o m e p a t i e n t s . I t is a p p a r e n t t h a t c o m p l e t e a o r t i c c l o s u r e a g a i n p l a c e s a s t r a i n o n t h e r e m a i n i n g d i s e a s e d val~-alar s t r u c ~ r e w h i c h is u n a b l e to w i t h s t a n d this a d d i t i o n a l stress. I t e o p e r a t i o n h a s b e e n r e q u i r e d in t~vo e a s e s to c o r r e c t this p r o b l e m . I n p a t i e n t s in w h o m a o r t i c s t e n o s i s is t h e d o m i n a n t lesion, b u t w h o h a v e v a r y i n g d e g r e e s o f a o r t i c i n s u ~ e i e n c y , t o t a l v a l v e r e p l a c e m e n t m a y n o t b e n e c e s s a r y to c o r r e c t t h e lesion; b u t in t h o s e p a t i e n t s in w h o m a n a d e q u a t e r e c o n s t r u c t i o n c a n n o t b e a c c o m p l i s h e d , t o t a l v a l v u l a r r e p l a c e m e n t is t h e t r e a t m e n t o f choice. R e s t o r a t i o n of a n o ~ a l b l o o d p r e s s u r e is s e e n a f t e r s u c h r e p a i r s w i t h a f a l l in t h e s y s t o l i c p r e s s u r e a n d a r i s e in t h e d i a s t o l i c p r e s s u r e . P u l s e c o n t o u r s also b e c o m e n o r m a l (fig. 2 ) . C m ' d i a c size d e c r e a s e s v e r y r a p i d l y a f t e r

283

AORTIC Ib/SUFFICIENCY

Pre Op.

Post. Op.

Fig. 2 . ~ A preoperative pulse tracing from the brachial artery is shown on the left. A tracing made immediately after operation is shown on the right. Normal tracings are maintained after operation. o p e r a t i o n in those p a t i e n t s w i t h c a r d i a c dilatation. T h o s e p a t i e n t s i n w h o m only" m u s c l e m a s s is i n c r e a s e d , c h a n g e s are less d r a m a t i c and slower. In s o m e p a t i e n t s c o m b i n a t i o n s of rnitral stenosis a n d m i t r a l i n s u ~ c i e n c y h a v e b e e n corr e c t e d a t t h e s a m e operation. In flue g r o u p of p a t i e n t s rims f a r r e p a i r e d fine c o m b h n a t i o n of mitrM i n s ~ c i e n c y a n d aortic i n s ~ c i e n c y ha s b e e n t h e m o s t d ~ c u l t l e sion to h a n d l e surgic a lly. M a n y of the p a t i e n t s fin this g r o u p h a v e b e e n f a r a d v a n c e d in t h e i r d i s e a s e process, s h o w i n g s e v e r e a n g i n a , c o n g e s t i v e f a i l u r e w h i c h is d i ~ c u l t to control m e ~ c a l l y , a n d the o t h e r u s u a l signs of far a d v a n c e d disease. F o l l o w i n g o p e r a t i o n a n g i n a pectoris h a s d i s a p p e a r e d as h a v e e v i d e n c e s of c o n g e s t i v e failure. T i l e risk of o p e r a t i o n h a s b e e n d i r e c t l y r e l a t e d to t h e s t a g e of flae p r o c e ss whie~h t h e p a t i e n t m a n i f e s t s a t t h e ~ e of operation. T h o s e p a ~ e n t s w i t h a d v a n c e d d i s e a s e w h o h a v e b e e n c o n s i d e r e d pretermianal h a v e h a d a h i g h o p e r a t i v e risk in t h e early stages of this series, whale m o r t a l i t y f o r that g r o u p in e a r l i e r stages has b e e n e i a b l y lower. T h u s f a r all p a t i e n t s w h o h a v e b e e n offered surgica l c or r e c tion h a v e b e e n class III or IV, a n d v ~ t h t h e s e c a n d i d a t e s as t h e t e c h n i c s h a v e i m p r o v e d t h e results h a v e b e e n c o n s t a n t l y m o r e satisfactory. T h e ove r a ll m o r t a l i t y r a te is 20 p e r cent; h o w ever, t h e results i n t h e last 50 eases w o u l d i n d i c a t e tha t t h e o p e r a t i v e risk for p a t i e n t s in class III is a p p r o x i m a t e l y 10 p e r cent, b u t for p a t i e n t s in class IV t h e risk is still 25 p e r cent. T h o s e p a t i e n t s wir e m a n i f e s t u n c o n t r o l l a b l e cong e s t i v e f a i l u r e c a n b e offered o n l y s a l v a g e ~ e o p e r a t i o n s w i t h h i g h risk. T h e m a n y t e c h n i c a l i m p r o v e m e n t s in the o p e r a t i v e p r o c e d u r e as well as tile i n c r e a s e d u n d e r s t a n d i n g of the pre- a n d p o s t o p e r a t i v e p r o b l e m s h a s cont r i b u t e d to the m a r k e d i m p r o v e m e n t in the correction of the se lesions. Ess e n t i a l l y all of the lesions of aortic insuf llc ie nc y c a n b e h a n d l e d s a t i s f a c t o r i l y b y operation. E x p e r i e n c e s w i t h t h e m o r e u n c o m m o n varieties of a or ti c ins u t ~ c i e n c y has g r o w n n l p i d l y q n d solutions to the se u n u s u M p r o b l e m s h a v e b e e n d e m o n s t r a t e d . Resection *of tim a s c e n d i n g aorta witli r e p l a c e m e n t b y

284

C~,~AIILES A. HUFNAGEL

graft and the correction of ascending arch dissecting aneurysms have been satisfactorily accomplished: Although improvements in many details are constantly being made, the basic principles for correction of aortic insu~ciencv are • now well delineated and the measures for the c~rrectlon o f the mechalfical defect are available to all patients with serious d e g r e ~ of aortic leakage. The technical achievement has been possible not only in the pure lesion of aortic ~'n~r,i~no~ h~d" hi.on w h ~ . n t'hi~ m a y h e combined with varying d e e r e ~ of

Charles A: Hufl,mgeli M.D., Professor of Surgery, Georgelown University Medical School, WaShington, D. C.