CLINICAL

STUDIES

Long-Term Follow-Up of Patients Undergoing Closed Transven Mitral Commissurotomy: A Useful Surrogate for Percutaneous Mitral Valvuloplasty? CHARANJIT ROBERT DAVID

S. RIHAL,

L. FRYE, R. HOLMES,

Rochesrrr,

*bje&e. oulrolneand

MD,

MD, HARTZELL FACC.

JR., MD,

KENT

V. SCHAFF. R. BAILEY.

MD. FACC.

PHD. LAVON

N. HAMMES.

FACC

Minnesoro

The

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underwenttransventriadarmitral eammiwrotomy at the Mqo Clinic ia lbe early 19&k Back,pund. Percutaomus ballann mitral valvulaplasty is a” bnpartardnew prwedurefor whichloo@erm follow-updataare ““t yet available.However,rwh data do existfor patientswho bavr undergone bansverdriadaxnitrat rammkwrotorny,a simUar bd dder aad ewe invnsivrprwedore. Metlwds.Follow-updata @wattduraiion 13.9 years)ior 107 mkswtomy wereobtainedfrom medid recwds.referringp&y. stctaq questimtirer awJ telephoneinterviews.Survivaland survivalfree al repeatcanmbwatamy or mitral valvesurgery wereestl(ilapted with the Kaplan-M&r method.Cox propartio”al hnrds m&l was lied to detentdoepredictan“f ~rvlval ar,d repeatmltral valvesurgery. Rem&s. Postap~tively, 92% of patientshad symptomatic

Percutaneousballoon mitral valvuloplasty is emerging as an attractive therapeutic alternative to operative commissurotcmy in selected patients with symptomatic mitral stenosis (I-6). As experience with percutaneousballoun mitral valvulaplasty has accrued, important inforomtion regarding procedural technique (7.8). patient selection criteria (9.10). immediate res:dts (4.1 .l2) and immediate complications (K-15) has become available. However, becausethis procedure has been introduced relatively recently, only- short-term follow-up data are available (3.4,8,16). ‘Thelongestfollow-up ofany publishedreport was 27 months(5). Nevenheless. as is true of any invasive procedure, illl estimation of the potential for long-term clinical improve-

t

ment is crucial in the clink-~1decision-ma!& processand is necessaryto determine the ultimate value of percutaneous balloon mitral valv”loplasty. We believethat follow-up data from paticna undergoingtliinsveniric”lar miirat valve coinmissumtomy may be a useful surrogatefar percutaoeuus balloon mitral valvuloplastybecauseof the technical eimllarities !wtween the two procedures. Both proceduresinvolve “envisually directed dilation of the stenotic mitral valve orifice: in percutaneousballoat mitral valvuloplasty, balloons are placed under Ruoroscopiccontml and then inflated. whereasin tmnsventricularmitralvalvecommiisurotomy the dilator is positionedand openedafter traosventricular pbwment. The eiTlcacyof both prwedores depends on adeqoze :ommissuralsplitting (17.18;. Patientslikely to benefit from eitlwr procedure ax relatively young with mobile, relatively noncalcifiedleatletsand IiItle subvaivular fusion ll9.20). Although percutaneousballoon mitral v&oloplarty is a relaively new invasiverecbqae, transve&~ular mitral valve commissuroiamy is a matwe surgical procedurewith >30 years of experience in its uss (21-261. Here. we repon locg-term rescltn (mean follow-up interval

13.9 years) of 267 patients who underwG closed transveniricular mitral commissurotomy at the Mayo Clinic.

Methods Subjects. From 1960 to I!& 267 pataenis with a mean age of 43.6 yews irxge 14 to 691 underwent transventricular mitral conmussurolomy at the Mayo Clinic. The immediate results and complications for this series were reported previously (21). All patients with severe. symptomatic mitral stenosis were considered for commissuroiomy. but those with heavily calcified. immobile valves, significant mitral regurgitation or muitiva;vuldr disease were thought to be better suited for valve replacement and were excluded. A previous commissurotomy or history of an embolic phenomenon was not considered a iontramdication to the procedure (21). Only 9% of patients underwel.. preoperative diagnostic cardiac cslheterization because this procedure was noi roufinely performed at the time OUT patients underwent operation. Our study was conducted with the apprwxd of the Clinical Practice Committee of Cardiovascular Diseases and Internal Medicine at the Mayo Clinic. Operative iechniqw. Transveniricular mitral valve commissurotomy was performed, as described previowly (181. through a left lateral thoracoromy. The left atrial appendage was opened and the right index finger was positioned ai the inlet of the mitral valve. allowing palpation of the fused leaflets. A transventricular dilalor was advanced through an apical ventriculalomy to the mitral valve orifice. The dilator was then positioned across the mitral valve orifice by tion and opened one to four times. Data collection and analysis. Information collected from the medical records included baseline demogaphic data. elecimcardiographic (ECG) and roenigenographic results. and the findings, ~sults and complications of the operations. Follow-up data were obtained from medical records and by contact with referring physicians, questionnaire and. if necessary, telephone. The specific follow-up data recorded included vital states. cause of deaib, symptom status, need ‘-I repeat dilation or mitral valve iaplaccment and occwrence of stroke. The mean follow-up interval was 13.9 years (range 0 to 34.7). with 98 patients under observation at 20 years. Survival and survival free of repeat commissurotomy or miira! velve su~ery were estimated as a function of time from initial dilation by using the Kaplan-Meier product limit method. Life-table probability of survival is presented as percent ? SE. Predictors of survival and repeat mitral valve surgery were determined by Cox pruporiional hazards analysis with the use of bmh univariate and multiwiate nodels. Patients with mitral anu!us calcification or with left atrial rnmmhi were identified. and the remainder we:e analyzed as a separate subgroup to approximate better the patient pop ulation currently considered suitable for percutaneous balloon mitral vnlvuloplasry.

palpa-

Resu!ts Baseline chplacieristier. Of the 267 patients studied, 207 (78%) were female and 60 (22%) were male (Tabi: I). The mean age at operation was 43.6 yezs. Ninety-six percent of patients had dyspnea, which in 61% was functional siass ii: or IV according to the New York Heart Association classification. There was a history of transient iscbemic attack or stroke in 14% of patients. Peripheral embolism had occurred in I I%. and mild mitral regurgitation, it.e most commonly associated cardiac abnormality, was present in 19.5%. There was atrial fibrillation in S4% of patients and ECG evidence of right ventricular hypertrophy in 34%. Chest roentgenography and Ruoroscopy documented left atrial enlargement in 90% of patients and calcification of the mitral vatve in 20%. On the basis of the medical history, physical findings and test results, the degree of mitral stenosis was thought to be severe in 19.8% of patients, moderate in 14.6% and ;nild in Z 6%. Sulqlcal Wings and lale outcome. A left atrial thrombus was identified in 24% of patients at operation. At 30 days postoperatively, 2.6% of pdiienis had died, I.% had had strokes and 1.1% had sustained B peripheral thromboembo. lism. Postoperatively. 32% of patients had relief from car disc symptoms. This improvement lasted from 2 ye.w for l2:l% of patients, from 3 to 4 wars for 24.4%. from 5 to IO years for iS.S% and from IO to 20 yew fcr?4.4% (Fig. I). Thus. symptomatic improvement was sustained for a3 to 4 years in 78% of our patienrs. Long-term ~sults for our patients are depicted in Figure

I to

the panems had undergone mttral va!vc replacement. and at IO yran. 25%. Repeat mttral valve ddatwn was also performed wth maeasing frequency: by IO years, 34% uf all pauents bad required either rrpeat surgical commtssurotony or mitral valve replacement. The probabdity of being alive and free of repeat mitral va!x opertisn L 5 ?EXj. *as 83.C I 2.5%. at IO ye*,3 wa, 56.7 2 3.4% and at 20 years was 24.4 + 3.1% (Fig. 2). After imtial commi~surotomy, mo=~ patients did not rxpcrieoce any transient or Axed cerebrovascular event. At 10 years. 90% of p&nts were free of any such event. and 46% were taking coumadm at the time of their last evaluation. Subgroup analysis. Currently at the Mayo Clinic. all patients under consideration for percutaneousballoon mitral vslvuloplasty undergo tmnsesophageal echocardiogaphic examination so that those with left atrial thrombi can be 2. The probabiiiry of survival was 79 + 2.7%. 66.8 z 3% excluded (27). Also, dense calcification of the mitral valve and 55.3 ? 3.5% ttt IO, IS and 20 years. respectively. Most and anulus decreasesthe likelihwd of a successful, uncom(74%) ofthe deaths that occurred during the follow-up period plicated immediate result (9,IO,28) and may be a contraindiwere due to cardiovascular causes. In 33% of cases. death cation to the procedure. Therefore. to approximate better was related to complications of mival valve disease and in the patient population currently undergoing percmatteous 13% to acute myocxdial infarction. The other cardiovascuballoon mitral valvuloplasty. patients with calcification of lar causes of d&h included sudden death (9%) and stroke the mitral valve seen on chest roentgenognphy or !ef! at+! (6%). thrombt found at operation were identified (gmup 2. a = An increasing number of patients required mitral valve 103). and the remaining I64 patients were snatyzzd as t. replacement during the follow-up period. At 5 years. 8.9% of separate rubgroup (group I,. Generally. the long-term results of group (Fig. 3): life-table probabilities rf were 84.2 + 3.0% of rbe FIgwe 2. Top, KaplawMeier life-tableprobability of at IO ycar~ and 63.4 i 4.4% at 20 years..These values are in study subjectsWavy tine, by numberof yearsaftertranrventricular contrast to life.tahle probabilities of survival of70.3 t 5.U% mitral commhsumtomy comparedwith that for age- md genderat IO years and 41.9 + 5.7% at 20 years for grcily 2 patients ma’?hedwnttol subjects(thin line) (p < O.&WI). B&tom. Kaplan. (D = O.CW2t. The life-table mobabilitv >f freedom from I! ‘x fife table for survival and survival free of repeatmitral valve op. .-lion by number of yeam after initial closed transventncular death x repeat mitral valv.: operation was also significantly ccmmu~ ~mtomy. Numbers in parenthesesrefer to the number of better: it ~a, 84.9 2 2.9% at 5 years and 65.4 f 4.1% at IO patients xder observation.Ermr bars represent2 SE. years forgroup I and 12.2 2 4.h%a:5 yearsand42.3 L 5.5% at 10 pears for group 2 (p < O.cJxQI). Ptwliclors of ott*,wm. The results of cox prowxtional hazards analyses of survival and survival free if repeat mitral vaive surgery are g&t in Tables 2 and 3, respxtively. Many variables (the baseline characteristics outlined in Table 1 DIUSconcomitant valvular lesions) were exattined by using both univatiate and multivatiate models. Two of three i&dependent predictors of survival (age and male gender) \xere of a general rather titan a cardiovascular nature. However. the rmence of atrial fibrillation. perhaps reprcsenliog more &anced heart disease, was alfo in&pendently associatedwith a greater ha;ud ratio of dying in long-tern, follow-up. Cxdiomegaly. rr.itral valve calcitica!ion CTleft atrid thmmbi were univariate predictors ofdeath, whereas concomitant mitral regurgitation faded to reach xattzticzl sI:niF.culce z! !k: 0.95 level. On the other band. anatomic and phyriologtc characteristics of mitml valve disease proved tb be me important univariate ana multivariate predictors of freedom from repeat ,mitral valve surgery. Not unexpectedly, mitral valve calcdication a2d concom!tant m;:rz! regurgitation were two

1were superior survival

survival

.

,

The multivariate proponianal hazards modeis were also used fo gain further perspective on potential long-term outcomes after trassieiltriciilai mirral commissurotomy: the pwdicred long-ferm pwxnt survival and predicrrd percent freedom from repeat mitral valve surgery for pa tients in Ihe risk ca@wies defined by our multivariate mcdels were calculated and are displayed in Tables 4 and 5, respectively. For example, a SQyear old woman wi’:l symptomaric mirral stenosis, in normal sinus rhythm and wthout significant mhrai zdciiication, mitral rcgurghatiora or cardio&galy would have an 85.4% chance of living IO wars and an 84.5% chance of nvoidinz rerxat mitral of these predic!ors. Cardiomegaly, again perhaps nflecting more advanc-.d heart disease. was also independently .wocAted with higher hazard raoz.

Discussion The current series. On the basis of long-lerm follow-up Wean duralion 13.9 years), our study documents a favorable outcome for the majority of the 267 pa&n& who underwent

closed transventricular mitral commissuiotomy. Late survival was excellent, with the Kaplan-Meier iife-table probability of survival of 94%. 90% and 79(7r at I, 5 and IO years. respectively. Ninety-two percent of all the pauenls expenenced symptomatic relief after commissurommy. and for 78% of these patients, this relief was sustained at tewt 3 years. As expected, mitral valve replacement or repeat commissurotomy was necessary with increasing frequency as the number of years of follow-up increased. Nonetheless. at the end of to years, 57% of the patients were alive and had not required another surgical procedure. Despite the prevalence of left atria1 thrombi at operation. the perioperative and long-term rates for stroke after hansventricular mitral cornmissurotomy were very low in our series. Our study also documented the independent predxtors of ootc ae after transventricular mitral commissurolomy. Anatomic factors such as mitral valve calcification and the preseocc of mitral regurgitation

significantly increased the

of requiring future surgical intervention. These results are consistent with those of other investigator: (22.231 and with the short.term results of oercutaneous b&i mitral valvuloplasty (17). In summary, closed transvcntricular mitral commissurctomy as pSx!ned by su:&eoas at the Mayo Clinic from 19M1 IO 1964 provided excellent long-term palliation for patients with symptomatic mitral stenosis nod should be considered in selected patient+especially in countries where cardiopulmonary bypass is not readily available. Implications b prculan~s b&on mitral valwhplasty. We believe oar data provide a perspective on poteniial long-ten o”,comes after percutaneous baltwn mitral valvutoplssty, a procedure for which long-term data are not available. If patients with either cdcification of the miti v&e or left atriat thrombi in th. wwni series were excluded from analysis, the observed long-term outcome was better, with 65% of patients being both alive and free of repeat mittal valve operation at 13 years. Such a dts:jnction is important because pat’-nlr without these unfavorable chz~~ccrertstics belter approximate those undergoing txcutaneous balloon mitral vrdwloptarty. Although there are obvious differences in technique. likelihood

percutaneous balloon mitral valvulopiasty and traosventricular mitral valw com~irsurotomy both involve nonvisua!ly direcred dilatton oflhe mitral valve apparatus: for the former procedure. dilaiion is achieved with Auoroscopic guidance. and for the latter. the vatvutotome is placed usins palpation. With both prucedurer. sufficient pressure is often exerted to separate both the anterolateral and the posteromedial commissures l17.18.21.25). The patient p+pttlation currently considered soltable for percutaneous balloon mitral valvuloplasty is very similar to the pat!eni group repned here: relatively young patients with symptomatic mitral steoasis but with little regurdtation. with an opening snap and pliable and minimally calcified or fused leaffets.

We speculate that given ihe simdarities in patlent papalation. mechanism of dilation. symptomatic resolts (21.27) ar.J perioperative complication rates, the long-term results reported herein can be used to predict the oo!come of &ems undergoing percutaneous balloon mitral vatvuloplasty. tiowever. our data do not indicate which procedure is to be preferred nor do they consider open mitral commissurotomy. which is the preferred surgical procedure in many developed nations (29.30). The initial results of randomized trials (31.32) indicate that both percutaneous and transventricutar approaches to mitrat valve dilation are stiz and result in roughly equal hemodynamic and symptamaiic improvement. The ultimate acceptance of percutaneous balloon mitral valvuloplasty as standard treatment for sympio matic mitral stenosis will depend on the demonstration of continued long-term efficacy and safety.

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II.

results.

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