216 JACC Voi. 22, No. I

July 1993:216-220

-.

AMIKAM NIR, MD, DAVID J. DRISCQLL,

Rochester, Minnesotn

06jectiw.s. The pnrpose (I Lhis study was to assess whether there is deterioration of aerobic capacity over time after the Fontan operation in individna~

Beckground. We previously observ at maximal aerobic

capacity afieer the Fontan operation was lower in older salients than in younger patients. It was unclear whether this re~~en~~ a decrease in aerobic capacity with time after o function of studying patients of

ely. All! patients who had more than one

udy were included. There were 25 patien female), aged 3.8 to 39 years at the time of the operation. The iirst exercise test was ~~orrn~, on awzrage, 2.2 Fontan operation, and the last exercise test was average, 5.9 years (range 1.8 to 13) slyer the 0~raCiQn. Pn 11 patients. coronary sinus drainage was !*!I on %e guhn8iary venous side. Five patients had bad a previous ~9~~~ o~rati~n. Exercise was performed to exhaustion with ~rse of a 3.min incremental cycle protocol.

Rcsuh Exercise duration, oxygen uptake, BSoad pressure,

Several investigators (l-4) have cBescribed the cardiorespi-

ratory responses to exercise in patients who have had the modified Fontan operation. We (I) pnvious!y observed that maximal aerobic capacity after this operation was lower in older than in younger patients. Because that observation was based on findings in different patients studied at different ages, it was unclear whether a patient’s maximal aerobic power decreased with time after the operation. We now have studied 25 patients on at least two postoperative occasions. The phipose of this study was to assess whether there is deterioration of aerobic capacity over time after the Fontan operation in individual patients,

From the Section of Pediatric Cardiology, thebision of Thoracic Diseases and Internal Medicine, and the Section rf Cardiovascular Surgery, Mayo Clinic and Mayo Foundation, Rochester, Minnesota.

Manuscript received May 1 I. 1992; revised ma1 ber 13.1992. accepted January 4, 193.

,z+p; received Novem-

First Street, SWeRkhester, Minnesota 55905. ss for o esnonktkx David J. Driscoll. MD. Mxfo Cliaic, 2W

Qt993 by the American Cotiege of Cardiology

atients. The study group consisted of 25 patients who had a modified Fontan operation at the etween 1977 and 1989. All patients who came t inic for follow-up and had more than one postoperative exercise test were considered for the study. Of the 25 patients, 14 bad two studies, 7 had three studies and 4 had fonr studies. For the longest follow-up period possible, we used data from the first and the last studies. There were 19 mrle and 6 female patients. Their ages ranged from 3.8 to 39 years at the time of the Fontan operation, from 5 to 41 years at the time of the first postoperative exercise test and from 6 to 44 years at the time of the I& exercise test. The mean interval between the operation and the first exercise test was 2.2 years (range 2.1 months to 6 years), between the operation and the last exercise test was 5.9 years (range 1.8 to 13) and between the first and the last postoperative exercise tests was 3.5 years (range 1 to 8).

The preoperative diagnoses were tricuspid atnsia in I0 patients, univentricular heart in 7 and other complex forms

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PACC Vd. 22, No. I July 1993:216-220

in after exercise teshg. Blcod

meter connect

anastomosis had been previously ~e~o~rned on the left side. Arterial blocld oxygen saturation &as measured contizuous?y by ear oximetry (Hewlett-Packard 47201 ear oxi

dioxide production were mea- t placed distal to a 64iter mixing alysis, Volume was determiced

Electronically by i~teg~~ti~g tha flow signal, and the gases were analyzed with a mass spectrometer previously cali- brated with gases analyzed by the HaPdane Iecimique. Ef- fective pulmonary blood w was measured at rest and at e2cb yro& load v~;th +l.* . .,.a .11‘1 CIIb tylciie hekm rebrearhing tech- nique (6).

aly&§. ecause we considere the last ex:rcise tests for each patient, each patient se his or her own control. To index for norm expressed the data as percent of predicted normal values for age and gender or indexed for body size. The change from the first to the last test and the rate of change (the change divided by the interval between the two tests) were assessed for each variable. The relation between these two deperFdent variables and the independent variables of age of the patient at the time of operation and age at the time of the first exercise test were studied using linear regression. The change from the first to the last test was also correkd to the time interval between the two tests to detect progressive changes. The Student paired I test was used to pare both

alues and results of the and last exercise s&dies. a~~~~~~~tney rank correlation and un- paired Student t tests were used to compare di

?igw IL Maximal aerobic catacity: tota? wor~k, exercise time, and rvlaximai oxygen uptake (Co; max) exprcsszd as percent of pre- dicted values during the first exercise tests.

indicate mm v

4. Al? vahes are re 0.05 is co~s~~e~ed si~~~~ca~t.

earl value +- P SD; p <

11 ,yitiew, exetcised t8 wa: ~e~m~~ated by

e was subnormal

and 57 t 17% of

y~a~~cs~ Heart rate was normal at rest in both postoperative studies and increase

significantly more in older t;lan in younger patients both at rest and with exercise (p < 0.85 for both) (Table 1). Systolic

were similar for bot sed s~gni~ca~t~y with

exercise in both 3 2 i2%and82 + 11% of predicted values in the first and last studies, respectively. There was no significant dizerence in peak systo pressure dming exercke between the two studies. b?ood pressure was normal at rest id iCt?! k?X~~CI

studies (Table 1).

measured in 87 pati patients during the set measured both times). cise in both studies: and there was no durLt, lL.Y,.nrr I ‘mm mauiqa] ey_e+.P bPfI?IPf-g t?a.P I???9 me

1

JACC Vol. 22. Pi.>. i hiy 1993:216-220

‘dears between first and last test

re 3. iffennce in peak exercise arterial blood oxygem saitura- nt and the last exercise tests, relate

interval between the Iwo tests.

premature ventricular complexes. In

in6 the last ~osto~erat~vc study, ST segment change > i mm developed in 5 (25%) of 20 patients; however, this difference was not statistically significant.

Several investigators have demonstrated that aerobic capacity and cardiac output responses to exercise in patients who ha.ve had the Fontan operation are subnor This is not su~risi~g because systemic v depends on passive pulmonary blood flow systemic ventricular function is usuaiiy previous study, we demonstrated that maximal aerobic capacity (corrected for growth and age) dec!ined with in- creasing age both in patients with functional single ventricle before the Fontan operation and io patients who had had the

serial exercise testin

r&e after the operation. a~e~~veoous Astulas can

after the Fo’-s-ntanr operation.

tween the atria or betwe

would be expected to shernt and should be assocmte

most impmtant determinant of persiste

220 NIR ET AL.. EXER,“ISE TOLERANCE AFTER THE FBNTAN QPERATIION

JACC Vol. 22, No. I July 1993:216-220

the Fontan operation is probably_ abnorma! pu!mona;y vcn- tzaiion and perfusion matching. Matsushita et ai. (;O) dem- onstrated that after the Fontan operation, the upper lobe/ !_o~er lobe perfusion ratio is abnormally increased. These investigators thought that this abnormality in perfusion was

relate3 ao increased pulmonary vascular resistance and that abnormalities in pulmonary vascular resistance could result from relatively low pulmonary blood flow. Cloutier et al. (I 1) and others (12) suggested that pulmonary arteriovenous fistulaformation after the Fontan operation could explain the decrease in exercise oxygen saturation.

3. Diversion of coronary sinus blood to the physiologic left atrium can result in a right to left shunt and hypoxemia. There is some evidence that increased coronary sinus blood pressure may be detrimental to myocardial function (13). Thus, some surgeons allow the OS of the coronary sinus to drain into the physiologic left atrium nfttF_tk Fx:cr. qxr-

ation. In this study, we observed u i. 9 ~onsignifkant trend in the decrease of peak exercise systemic arterial blood oxygen saturation with time, with a slightly greater decrcasc in subjects whose coronary sinus was left on the pulmonary venous side than those whose coronary sinus was left on the systemic venous side. There was an even greater decrease (but nonsignificant) in patients who had undergone a previ- ous Glenn operation. The observation that systemic arterial blood oxygen saturation during exercise late after the Fontan operation is decreased may be a clue that increasing cyanc- sis in these patients wiil gradually develop. A larger study of this type with a longer postoperative period of observation will be necessary to confirm or refute these findings.

A second interesting point that emerges from this stud,) is the decrease in heart rate (percent of predicted for age) from the first to the last test, which was more pronounced in older patients. A possible explanation for this abnormal sinus node function, which often occurs in patients with single ventricle.

Conclusions. In a very select group 0P patients, exercise tolerance remained relatively unchanged over the range of 13 years after the Fontan operation. A small but significant decrease in systemic arterial blood oxygen saturation oc- curred during maximal exercise with time after the Fontan operation. These resrilts suggest that, in addition to the

possible right to left shunt by abnormal v~nti~~to~y/~e~ns~Qn

e Fontan operations

1. Driscoll DJ, Danielson GK, Puga FJ, Schaff NV, Heise CT, Staats BA. Exe:& tolerance and cardiorespiratory response to exercise after the For~ua cperation for tricuspid atresia or functional single ventricle. J Am Coil Car:%ol 1986;9:1’397-91.

1 . Ben Shachar 6, F&man BP, Wang Y, Lucas RV Jr, Lock JE. Rest and exercise hemodynamici after the Fontan procedure. Circulatioo 1982;45: 1043-g.

3. Gewillig W;H, Lundstrom UR, Bull C, Wyse RK, Deanfield JE. Exercise responses in patients with congenital heart disease after Fontan repair: patterns and determinants of performance. J Am Coil Cardiol 1990;15: 1424-32.

4. Del Torso 7. K,rlfy MJ, KalEFV. Venables AW. Radionuclide assessment _P ..^_ r..:^,.l,.. “__!_ ..^ *‘a., ..I -..il.ii_...<.l . ..I 1111..-11. & t rest and during exercise following the Fontan procedure for eit,ler ttf&pid atresia G single ventricle.. Am J Cardiol 1985;55:1127-32.

5. James FW. Kaplan S, Glueck CJ, Tsay JV, Knight MJS. Sarwar CJ. Response of normal children and young adults to controlled bicycle exercise. Circulation 1980;61:902-12.

6. Triebwasser JH, Johnson o RP. Campbell JC, ka Blomqvist CG. Noninvasive determination of cardiac output by a modi- fied acetylene rebreatbing procedure utilizing mass spectrometer mea- surements. Aviat Space Environ 1977;48:203-9.

7. Rhodes 3. Garofano RP, Bowman FO Jr. Grant GP, Biermaa FZ, Gersony WM. Effecl of right ventricular anatomy on the cardiopu!monary re- sponse to exercilz impiics&ons for the Fontan procedure. Circulation 1990;81:1811-7.

8. Zellers TM, Driscoll DJ, Mottram CD, Puga FJ, Schaff GK. Exercise tolerance and cardiorespiratory response to exercise before and after the Fontan operation. Mayo Clin Proc 1989;64:1489-97.

9. Feldt RN. Fontan operation for complex cyanotic heart disease. Curr Opin Pediatr 1991:3:8lO-5.

IO. Matsushita T. Matsuda H, Ogawa WI, et al. Assessment of the intra- pulmonary ventilation-perfusion distribution after the Fontan procedure for complex cardiac anomalies: relation to pulmonary hemodynamics. J Am Coil Cardiol 1990;15:842-8.

pulmonary blood flow after the Glenn shunt or Fontan procedure: risk of II. Cloutier A. Ash JM. Smallborn JF, et al. Abnormal distribution of

development of arteriovenous Cstulae. Circulation 1985:72:471-9.

12. Moore JW. Kirby WC, Madden W.4, G&her NS. Development of m,imonarv arieriovenous malformations after modified Fontan ooera- iions. J Thorac Cardiovasc Surg 1989;98:1045-50.

13. llbawl LIN, ldriss ES, Muster AJ. et al. Effects ofeievared coronary sinils pressure on left ventricular function after the Fontan operation. An experimental and clinical corre!ation. J Thorac Cardiovasc Surg 1986;92: 131-7.