The significance of tricuspid regurgitation in hypoplastic left-heart syndrome

Palliation of hypoplastic left-heart syndrome involves use of the morphologic right ventrkle as the systemic ventricle and the tricuspid valve (in cases of mitral atresia/stenosls) or the common atrloventricular valve (in cases of malaligned atrioventricular canai) as the systemk atrioventricular valve. To determine the relationship between tricuspid or common atrioventricular valve function and the ultimate outcome of palliative surgery, 100 patients with hypoplastic left-heart syndrome were evaluated preoperatively by Doppier echocardkgraphy to determine the degree of tricuspid regurgitation. These patients were then foiiowed reriaiiy to assess changes with time in the functional status of the tricuspid or common atrloventrkuiar valve and to determine the correlation of tricuspid or common atrioventricular valve regurgitation with survival. We discovered that tricuspid or common atrioventrkuiar valve regurgitation is common in hypopiastic left-heart syndrome. Thirty-seven percent of the petients had mild, 13% had moderate, and 3% had severe tricuspid or common atrioventricuiar valve regurgitation on their preoperative Doppler echocardiograms. Throughout the first 2 postoperative years most patients had no significant change in the degree of tricuspid or common atrioventricular valve regurgitation when findings were compared to those of the preoperative echocardiogram. Patients with moderate or severe tricuspid or common atrioventrlcular valve regurgitation preoperatively had a significant reduction in their survival when contrasted with patients with no or mild atrioventricuiar valve regurgitation. We therefore conclude that tricuspid or common atrioventricular valve competence is a significant factor in long-term survival after paiilative surgery for hypoplastic left-heart syndrome. This function, however, appears to be unaffected by palliation and remains relatively constant over the first 2 postoperative years. (AM HEART J 1988;116:1563.)

Gerald Barber, MD, J. Gregg Helton, MD, Beth A. Aglira, BHS, RCPT, Alvin J. Chin, MD, John D. Murphy, MD, John D. Pigott, MD, and William I. Norwood, MD, PhD. Philadelphia, Pa.

In 1978 Albert and Bryant’ first described a tech- nique for repair of hypoplastic left-heart syndrome. This was followed by descriptions of surgical proce- dures for the treatment of this lesion by Mohri et a1.2 in 1979 and Norwood et al.” in 1980. Because the goal of therapy in this lesion (as in most single- ventricle complexes) involves a Fontan procedureP the tricuspid valve must be used as the systemic atrioventricular valve. The significance of preopera- tive tricuspid regurgitation has been questioned previously.6 To determine the significance of tricus- pid (or common atrioventricular valve) regurgitation in hypoplastic left-heart syndrome, we serially eval- uated the degree of regurgitation from the preoper-

From the Divisions of Cardiology and Cardiothoracic Surgery, The Chil- dren’s Hospital of Philadelphia, and the Departments of Pediatrics and Surgery, University of Pennsylvania School of Medicine.

Received for publication Jan. 15, 1988; accepted July 7, 1988.

Reprint requests: Gerald Barber. MD, Children’s Hospital of Philadelphia, 34th St. and Civic Center Blvd., Philadelphia, PA 19104.

ative period through the first postoperative years and assessed its correlation with survival.

METHODS

Patients. From October 1984 through March 1987, a total of 114 patients with hypoplastic left-heart syndrome underwent palliative surgery at The Children’s Hospital of Philadelphia. Of these 100 had undergone preoperative echocardiography, which permitted the determination of tricuspid regurgitation. These 100 patients represent the final study population. There were 53 males and 47 females in the study population. Anatomic diagnoses included mitral and aortic atresia or severe stenosis with normally related great arteries (71 patients), mitral and aortic atresia or severe stenosis with double-outlet right ventricle (14 patients), atrioventricular canal malaligned to the right6 with normally related great arteries (8 patients), and atrioventricular canal malaligned to the right with double-outlet right ventricle (7 patients). Only three patients underwent preoperative cardiac catheter- ization.

The following materials were used for aortic arch aug-

1563

1564 Barber et al. December 1988

American Heart Journal

Fig. 1. A, Apical four-chamber two-dimensional echocar- diogram from patient with hypoplastic left-heart syn- drome. 6, Turbulent systolic flow of tricuspid regurgita- tion. RA, right atrium; RV, right ventricle. Arrow points to sample volume.

mentation: polytetrafluoroethylene patch (18 patients), autologous pericardium (12 patients), and pulmonary artery homograft (70 patients). All-patients with polyte- trafluoroethylene patch or pericardial augmentation and 23 patients with homograft augmentation underwent a modified right Blalock-Taussig shunt procedure. The remaining 47 patients with homograft augmentation had a polytetrafluoroethylene central shunt placed from the underside of the aortic arch to the pulmonary artery confluence. The mean age at operation was 14 days with a standard deviation of 35 days (range 0 to 303 days). The median age at operation was 6 days with only eight patients operated on at more than 30 days of age.

METHODS

A Hewlett-Packard 77020AC phased-array scanner (Hewlett-Packard Co., Andover, Mass.) was used for standard two-dimensional echocardiographic and pulsed Doppler examinations. The anatomy of the tricuspid valve ._i i ~U~~~~~~~~i aLriovem,ricular valve was assessed by means of subcostal imaging.7 Mapping was performed from the apical, parasternal, and subcostal windows (Fig. 1) with the use of 5 mHz and 3.5 mHz transducers. The degree of

50

40

30

20

IO

0

NONE MliD MODERATE SEVERE

n MITRAL ATf?ESIA/STENOSIS

MALALIGNED AV CANAL

Fig. 2. Degree of tricuspid regurgitation preoperatively for patients with mitral atresia/stenosis vs malaligned atrioventricular canal. y Axis is percentage of patients in each category. Numbers above bars refer to actual patient numbers in each category.

preoperative tricuspid regurgitation was graded as none, mild, moderate, or severe by pulsed Doppler mapping of the regurgitant jet in the right atrium. If tricuspid regur- gitation was detected an estimate was made of the relative area of the right atrium in which the regurgitant jet could be detected by pulsed Doppler technique. Tricuspid regurgitation was graded as mild if the regurgitant jet was detected in less than one third of the area of the right atrium, moderate if the regurgitant jet could be detected in more than one third but less than two thirds of the right atrium, and severe if detected in more than two thirds of the right atrium.

The presence and degree of tricuspid regurgitation determined by preoperative echocardiography were assessed retrospectively for the first 19 months of the study and prospectively thereafter. For the purposes of this study the postoperative echocardiograms were divid- ed into two groups: those obtained within the first postop- erative month (early) and those obtained after the first postoperative month (late). Early and late tricuspid regur- gitation was correlated to the degree of preoperative tricuspid regurgitation. Survival was correlated with the degree of preoperative tricuspid regurgitation.

Chi-squared analysis, life-table analysis, and signed- ranked test were used in the statistical analysis.

RESULTS

Preoperative data. Preoperative tricuspid or com- mon atrioventricular valve regurgitation was absent in 47% and mild in 37% of the patients. Thirteen percent had moderate regurgitation, and the remaining 3% had severe regurgitation. There was no difference in degree of preoperative atrioventric- ular valve regurgitation between patients with mitral atresia/stenosis and patients with a mal- aligned atrioventricular canal (Fig. 2). No ana-

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Table I. Preoperative vs early postoperative tricuspid regurgitation

Preoperative Early

postoperative None Mild Moderate Severe Total

None 14 16 1 0 31 Mild 7 6 2 1 16 Moderate 2 5 4 0 11 Severe -!2 r P 1 2 Total 23 26 7 2 60

tomic abnormalities of the tricuspid valve were noted.

Early postoperative data. Sixty of the 100 patients underwent postoperative echocardiography within the first postoperative month. The mean interval between palliation and early postoperative echocar- diography was 14 + 8 days (median = 14 days, range 0 to 30 days). The change in tricuspid regurgi- tation from preoperative echocardiography to early postoperative echocardiography is given in Table I. According to results of a two-sample signed-ranked test on paired data, there was no significant differ- ence in the degree of tricuspid or common atrioven- tricular valve regurgitation during the first postop- erative month when compared to the preoperative period.

Late postoperative data. Twenty-six of the 60 patients with early postoperative echocardiograms underwent subsequent echocardiography more than 30 days after palliation. The mean interval between palliation and late postoperative echocardiography was 206 f 128 days (median = 170 days, range 57 to 504 days). The change in degree of tricuspid regur- gitation from early postoperative echocardiography to late postoperative echocardiography is given in Table II. According to results of a two-sample signed-ranked test on paired data, there was no significant change in the degree of tricuspid regurgi- tation within the first 2 postoperative years.

Survivat data. The 2-year actuarial survival as a function of the degree of preoperative tricuspid regurgitation is shown in Fig. 3. Survival was signif- icantly reduced in patients with moderate or severe tricuspid regurgitation preoperatively when com- pared to those with no regurgitation or mild preop- erative tricuspid regurgitation. As would be pre- dicted the excess mortality among patients in the group with moderate-to-severe tricuspid regurgita- tion occurs within the first 2 postoperative months. Thereafter the survival curves parallel each other indicating no continuing increased risk for patients

Tricuspid regurgitation in hypoplastic left heart 1565

% SURVIVAL

100 B 80

60

40

20

0 0 3 6 9 12 15 18 21 24

TRICUSPID REGURGITATION

n NONE/MILD @ MODERATE/SEVERE

Fig. 3. Life-table survival data for patients with hypo- plastic left-heart syndrome based on degree of preopera- tive tricuspid regurgitation. Numbers above lines repre- sent number of patients still in study at each time period.

in the group with moderate-or-severe tricuspid regurgitation. Because of the high initial mortality only 2 of 16 patients in the group with moderate or severe tricuspid regurgitation have subsequently undergone a Fontan operation compared with 20 of the 84 patients in the group with no or mild tricuspid regurgitation. It is thus currently impossi- ble to determine whether the degree of tricuspid regurgitation also adversely affects survival after the second stage of repair in hypoplastic left-heart syndrome.

DISCUSSION

Attempts at surgical palliation of hypoplastic left-heart syndrome date back to 1978’ with the most frequently used palliative procedure being that described by Pigott et aLa This palliation involves use of the right ventricle as the systemic ventricle by transection of the main pulmonary artery, division of the ductus arteriosus, anastomosis of the proxi- mal portion of the pulmonary artery with the hypo- plastic aorta, augmentation of the aortic arch, and creation of a systemic-to-pulmonary artery shunt. After this palliation the tricuspid valve (in cases of mitral atresia/stenosis) or the common atrioventric- ular valve (in cases of malaligned atrioventricular canal) functions as the systemic atrioventricular valve.

A previous study5 attempted to identify anatomic and physiologic determinants of outcome after pal- liative surgery for hypoplastic left-heart syndrome. Helton et al5 examined whether right ventricular wall thickness, right ventricular shortening, tricus- pid regurgitation, ascending aortic size, distal aortic

1566 Barber et al. December 1988

American Heart Journal

Table II. Early vs late postoperative tricuspid regurgita- tiop

Late Early postoperative

postoperative None Mild Moderate Severe Total

None 8 1 1 0 10 Mild 4 5 3 0 12

Moderate 1 1 1 0 3

Severe 9 0 Q L _L Total 13 7 5 1 26

arch anatomy, and atrial septal anatomy correlated with early (<30 day) mortality after palliative sur- gery. They found that the patients with moderate- to-severe atrioventricular valve regurgitation “tended to have a higher early mortality.” However, the number of patients with moderate-to-severe atrioventricular valve regurgitation in their study was too small to prove that the mortality was statistically different from that among patients with no or mild atrioventricular valve regurgitation. Even by multivariate analysis none of the other five factors that they evaluated correlated with survival. The relationship between multiple preoperative metabolic parameters and early and long-term sur- vival has also been evaluated by multivariate analy- sis (Barber G, Unpublished data). To date none of these parameters has been found to correlate with either short- or long-term survival or preoperative or postoperative tricuspid or common atrioventricular valve insufficiency.

The ability of the tricuspid valve to function as the systemic atrioventricular valve has been ques- tioned since the early days of the Mustard operation for transposition of the great arteries.9 The function of this valve should be no less important in hypo- plastic left-heart syndrome.

Follow-up in this study was limited to the first 2 postoperative years to avoid adding the confounding variable of the second stage of the palliation, that is, a Fontan repair, to the analysis. Furthermore, because of the mortality associated with moderate or severe tricuspid or common atrioventricular valve regurgitation, insufficient numbers of patients in this category have undergone a Fontan repair after palliative surgery for hypoplastic left-heart syn- drome to make any meaningful statistical assess- ment of the effects of moderate or severe tricuspid irs ~UIUAIIUII at&ventricular valve regurgitation on survival after the second stage of the operation. Moderate or severe tricuspid or common atrioven-

tricular valve regurgitation is theoretically detri- mental after a Fontan procedure for hypoplastic left-heart syndrome, because significant regurgita- tion of the tricuspid valve results in elevated left (pulmonary venous) atrial pressure. During the “v- wave,” left atrial pressure can exceed right atria1 pressure throughout systole and much of diastole. Pulmonary blood flow is thus arrested for all but a short time in late diastole. With an already dimin- ished cardiac output after a Fontan procedure,lOs l1 anything that further reduces cardiac output may result in untoward hemodynamic consequences.

One potential limitation of our study was that only three of the patients underwent cardiac cathe- terization and right ventricular angiography before palliative surgery. Pulsed Doppler echocardiography was used as the sole diagnostic modality. Neverthe- less in other settings Doppler mapping of the spatial extent of the regurgitant jet in the right atrium has been found to correlate well with the degree of insufficiency determined by ventriculography.12T l3 Although color flow mapping was not used in grad- ing the degree of tricuspid insufficiency in this study, the accuracy of assessing regurgitation would presumably be enhanced by this technique. We now routinely use color flow mapping to detect the presence of tricuspid regurgitation and its spatial extent in the right atrium.

A second possible limitation of the study is the fact that only 26 of the 60 patients in whom early studies were performed actually had long-term fol- low-up. It could be suggested that patients who had progression of their tricuspid insufficiency were dying and therefore dropping out of the study before follow-up echocardiography; however, if this had been the case a continued fall-off in the survival curve for the patients with no or mild tricuspid insufficiency should have occurred. Instead the sur- vival curve essentially plateaus after 3 months for both the groups with no or mild regurgitation and moderate or severe tricuspid regurgitation. Thus the lack of progression in severity of regurgitation observed in the group with no or mild regurgitation was not a result of loss of patients.

Our data establish that significant preoperative incompetence of the tricuspid valve is correlated with poor early and late outcome after palliative surgery for hypoplastic left-heart syndrome. We are currently attempting to treat this problem by means of tricuspid valve annuloplasty in those patients with severe tricuspid regurgitation who are not thriving after palliative surgery for hypoplastic left- heart syndrome. Further follow-up is needed to

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determine whether this policy improves survival after palliation and also after the Fontan opera- tion.

We did not observe an anatomic reason for tricus- pid valve dysfunction. Only rarely has anatomic abnormality of the tricuspid valve in hypoplastic left-heart syndrome been detected by pathologic review.14v15 Thus patients with little or no tricuspid regurgitation preoperatively will probably continue to have little or no tricuspid regurgitation postoper- atively.

Conctusions. Tricuspid regurgitation is an impor- tant finding in hypoplastic left-heart syndrome. The degree of tricuspid regurgitation tends to remain relatively constant from the preoperative through the late postoperative period. The degree of tricus- pid regurgitation is similar whether the patient has mitral atresia/stenosis or malaligned atrioventricu- lar canal. Moderate-to-severe tricuspid regurgita- tion was associated with diminished survival after palliative surgery for hypoplastic left-heart syn- drome. These patients should be considered for early annuloplasty or tricuspid valve replacement should they have any evidence of hemodynamic dysfunction after their palliative operation.

REFERENCES

1. Albert HM, Bryant LR. A proposed technique for treatment of hypoplastic left heart syndrome. J Cardiovasc Surg 1978;19:257-60.

2. Mohri H, Horiuchi T, Haneda K, et al. Surgical treatment for hynoplastic left heart syndrome: case reports. J Thorac Cardiovasc Surg 1979;78:223-8.

3. Norwood WI, Kirklin JK, Sanders SP. Hypoplastic left heart syndrome: experience with palliative surgery. Am J Cardiol 1980;45:87-91.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

Norwood WI, Lang P, Hansen DD. Physiologic repair of aortic atresia-hypoplastic left heart syndrome. N Engl J Med 1983;308:23-6. Helton JG, Aglira BA, Chin AJ, Murphy JD, Pigott JD, Norwood WI. Analysis of potential anatomic or physiologic determinants of outcome of palliative surgery for hypoplastic left heart syndrome. Circulation 1986;74(suppl):170-6. Barber G. Hypoplastic left heart syndrome. In: Garson Jr A, Bricker JT, McNamara DG, eds. The science and practice of pediatric cardiology. Philadelphia: Lea & Febiger, Publish- ers, 1989. Deal BJ, Chin AJ, Sanders SP, Norwood WI, Castaneda AR. Subxiphoid two-dimensional echocardiographic identifica- tion of tricuspid valve abnormalities in transposition of the areat arteries with ventricular septal defect. Am J Cardiol i985;55:1146-51. Pigott JD, Murphy JD, Barber G, Norwood WI. Palliative reconstructive surgery for hypoplastic left heart syndrome. Ann Thorac Surg 1988;45:122-8. Tynan M, Aberdeen E, Stark J. Tricuspid incompetence after the Mustard operation for transposition of the great arteries. Circulation 1972;45(suppl I):lll-15. Ben-Shacher G, Fuhrman BP, Wang Y, Lucas RV, Lock JE. Rest and exercise hemodynamics after a Fontan procedure. Circulation 1982;65:1043-8. Driscoll DJ, Danielson GK, Puga FJ, Schaff HV, Heise CT, Staats BA. Exercise tolerance and cardiorespiratory response to exercise after the Fontan operation for tricuspid atresia or functional single ventricle. J Am Co11 Cardiol 1986;7:1087- 94. Veyrat C, Abitbol G, Bas S, Manin JP, Kalmanson D. Quantitative assessment of valvular regurgitations using the pulsed Doppler technique. Approach to the regurgitant lesion. Ultrasound Med Biol 1984;10:201-13. Jacksch R, Karsch KR, Seipel L. Determination of the severity of tricuspid valve insufficiency using Dopper echo- cardiogranhv. Hem 1986;11:337-40. Lang P, Nor-wood WI. Hemodynamic assessment after pallia- tive surgery for hypoplastic left heart syndrome. Circulation 1983;68:104-8. Weinberg PM, Peyser K, Hackney JR. Fetal hydrops in a newborn with hypoplastic left heart syndrome: tricuspid valve “stopper.” J Am Co11 Cardiol 1985;6:1365-9.