Persistent pulmonary hypertension late after neonatal aortic valvotomy: a consequence of an expanded surgical cohort

Long-term outcome after neonatal intervention for congenital critical aortic stenosis

BACKGROUND

This study explored long-term outcome and functional status of patients born with critical aortic stenosis (CAS) following neonatal surgical or catheter interventions.

METHODS

A 40-year retrospective review of all consecutive patients within a large, single-center referral unit who required neonatal (<30 days) intervention for CAS. Additional detailed evaluation of surviving patients >7 years age was performed, with clinical assessment, objective cardiopulmonary exercise testing and state-of-the-art characterization of myocardial function (advanced echocardiography and cardiac MRI).

RESULTS

Between 1970 and 2010, ninety-six neonates underwent CAS intervention (mean age 9 ± 7.5 days). Early death occurred in 19 (19.8%) and late death in 10 patients. Overall survival at 10 and 30 years was 70.1% and 68.5%, freedom from reintervention was 41.8% and 32.9% respectively. Among the 25 long-term survivors available for detailed assessment (median age 15.7 ± 6.4 years), 55% exhibited impaired peak oxygen uptake. Mean left ventricle (LV) ejection fraction was 65 ± 11.2%, with a mean LV end-diastolic volume z-score of 0.02 ± 1.4. Mean LV outflow tract Vmax was 2.3 ± 1.02 m/s. CAS patients had reduced LV longitudinal and increased radial strain (p = 0.003, p < 0.001 respectively). Five patients had severe LV diastolic dysfunction associated with endocardial fibroelastosis (EFE) (p = 0.0014).

CONCLUSION

Despite high early mortality rate, long-term survival of patients with CAS is reasonable at the expense of high reintervention rate. With successful intervention, there remained long-term clinical and subclinical LV myocardial impairment, of which EFE was one marker. Long-term follow-up of all CAS patients is crucial, involving detailed myocardial functional assessment to help elucidate physiology and optimise management.

In utero intervention for severe congenital heart disease

The aim of foetal cardiac therapy is to treat an abnormality at the developmental stage so that the process of cardiac growth, which is complex and relies on the volume and direction of circulating blood as well as genetic determinants, can continue. In reality, most cardiac interventions are palliative; hence, major abnormalities are still present at birth. Nevertheless, tangible benefits following successful foetal intervention include improved haemodynamics and reduction in secondary damage leading to better postnatal outcomes. In cases of semilunar valve stenosis, or atresia, foetal valvuloplasty aims to achieve a biventricular, rather than univentricular, circulation. Opening and stenting a restrictive atrial foramen may preserve the pulmonary function in cases of hypoplastic left heart syndrome, thereby increasing the chances of successful postnatal surgery. More recent endeavours include percutaneous implantation of a miniaturised pacemaker to treat complete heart block and the promotion of left-sided heart growth by chronic maternal hyperoxygenation. The true clinical benefit of these interventions over natural history remains uncertain because of the paucity of appropriate randomised controlled trials (RCTs). Foetal cardiac therapy must now move from a pioneering approach to one that is supported by evidence, as has been done successfully for other foetal therapies.

EDUCATIONAL SERIES IN CONGENITAL HEART DISEASE: Prenatal diagnosis of congenital heart disease

This review article will guide the reader through the background of prenatal screening for congenital heart disease. The reader will be given insight into the normal screening views, common abnormalities, risk stratification of lesions and also recent advances in prenatal cardiology.

Fetal hemodynamic response to aortic valvuloplasty and postnatal outcome: a European multicenter study

OBJECTIVE

Fetal aortic stenosis may progress to hypoplastic left heart syndrome. Fetal valvuloplasty (FV) has been proposed to improve left heart hemodynamics and maintain biventricular (BV) circulation. The aim of this study was to assess FV efficacy by comparing survival and postnatal circulation between fetuses that underwent FV and those that did not.

METHODS

This was a retrospective multicenter study of fetuses with aortic stenosis that underwent FV between 2005 and 2012, compared with contemporaneously enrolled natural history (NH) cases sharing similar characteristics at presentation but not undergoing FV. Main outcome measures were overall survival, BV-circulation survival and survival after birth. Secondary outcomes were hemodynamic change and left heart growth. A propensity score model was created including 54/67 FV and 60/147 NH fetuses. Analyses were performed using logistic, Cox or linear regression models with inverse probability of treatment weighting (IPTW) restricted to fetuses with a propensity score of 0.14-0.9, to create a final cohort for analysis of 42 FV and 29 NH cases.

RESULTS

FV was technically successful in 59/67 fetuses at a median age of 26 (21-34) weeks. There were 7/72 (10%) procedure-related losses, and 22/53 (42%) FV babies were delivered at < 37 weeks. IPTW demonstrated improved survival of liveborn infants following FV (hazard ratio, 0.38; 95% CI, 0.23-0.64; P = 0.0001), after adjusting for circulation and postnatal surgical center. Similar proportions had BV circulation (36% for the FV cohort and 38% for the NH cohort) and survival was similar between final circulations. Successful FV cases showed improved hemodynamic response and less deterioration of left heart growth compared with NH cases (P ≤ 0.01).

CONCLUSIONS

We report improvements in fetal hemodynamics and preservation of left heart growth following successful FV compared with NH. While the proportion of those achieving a BV circulation outcome was similar in both cohorts, FV survivors showed improved survival independent of final circulation to 10 years' follow-up. However, FV is associated with a 10% procedure-related loss and increased prematurity compared with the NH cohort, and therefore the risk-to-benefit ratio remains uncertain. We recommend a carefully designed trial incorporating appropriate and integrated fetal and postnatal management strategies to account for center-specific practices, so that the benefits achieved by fetal therapy vs surgical strategy can be demonstrated clearly. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Persistence of pulmonary arterial hypertension after relief of left sided obstructive lesions in small infants: our experience

BACKGROUND

Infants with critical left sided obstructive lesions usually present with left ventricle dysfunction and pulmonary arterial hypertension (PAH). Left ventricular dysfunction and pulmonary artery pressures usually normalize after relief of obstruction. In some, PAH persists despite adequate relief of obstruction.

PATIENTS AND METHODS

We retrospectively reviewed records of infants (less than 3 months) who underwent intervention for left sided obstruction (n=50) over four years (May 2012-May 2016).

RESULT

We report four infants who had persistent of PAH despite relief of left sided obstruction. The causes of PAH were found to be high left ventricular end diastolic pressure(n=1), severe hypoplasia of pulmonary veins (n=1), stenosis of the lower branch of the right pulmonary artery (n=1) and non-regression of pulmonary vascular resistance (n=1).

CONCLUSION

That persistence of PAH after relief of obstruction should be investigated and other, less common causes should be sought.

The mid-term outcome of primary open valvotomy for critical aortic stenosis in early infancy - a retrospective single center study over 18 years

Background

The objective of this study was to examine early and long-term results of surgical aortic valvotomy in neonates and infants aged less than four months and to identify predictors of outcome.

Methods

Between August 1994 and April 2012, 83 consecutive patients younger than 4 months of age underwent open heart valvotomy for critical aortic stenosis in our institution. Median age was 17 days (range 0-111 days). We examined clinical records to establish determinants of outcome and illustrate long-term results.

Results

Fifty-six patients (67 %) were neonates. Associated cardiac malformations were found in 24 patients (29 %), including multilevel left heart obstruction in 5. The median follow-up was 4.2 years. The time-related survival rate was 87 and 85 % at 5 and 15 years, respectively. The time-related survival without reintervention was respectively 51, 35 and 18 % at 5, 10 and 15 years. The time-related survival without aortic valve replacement was respectively 67, 54 and 39 % at 5, 10 and 15 years. Ventricular dysfunction (p = 0.04), delayed sternal closure (p = 0.007), endocardial fibroelastosis (p = 0.02) and low z-score of the aortic annulus (p = 0.04) were found predictors of global mortality. Ventricular dysfunction (p = 0.01) and endocardial fibroelastosis (p = 0.04) were found predictors of reintervention.

Conclusions

The experience, in our center, on the management of critical aortic stenosis, shows a low early and late mortality, but the aortic valvotomy is a palliative procedure and we see unfortunately a high rate of reintervention among which the aortic valve replacement. These results suggest to reconsider the use of aortic balloon valvotomy, and particularly for the neonates with a low cardiac output in order to avoid the myocardial stress and the neurological injury due to the cardiopulmonary bypass.

Pulmonary hypertension caused by pulmonary venous hypertension

The effect of pulmonary venous hypertension (PVH) on the pulmonary circulation is extraordinarily variable, ranging from no impact on pulmonary vascular resistance (PVR) to a marked increase. The reasons for this are unknown. Both acutely reversible pulmonary vasoconstriction and pathological remodeling (especially medial hypertrophy and intimal hyperplasia) account for increased PVR when present. The mechanisms involved in vasoconstriction and remodeling are not clearly defined, but increased wall stress, especially in small pulmonary arteries, presumably plays an important role. Myogenic contraction may account for increased vascular tone and also indirectly stimulate remodeling of the vessel wall. Increased wall stress may also directly cause smooth muscle growth, migration, and intimal hyperplasia. Even long-standing and severe pulmonary hypertension (PH) usually abates with elimination of PVH, but PVH-PH is an important clinical problem, especially because PVH due to left ventricular noncompliance lacks definitive therapy. The role of targeted PH therapy in patients with PVH-PH is unclear at this time. Most prospective studies indicate that these medications are not helpful or worse, but there is ample reason to think that a subset of patients with PVH-PH may benefit from phosphodiesterase inhibitors or other agents. A different approach to evaluating possible pharmacologic therapy for PVH-PH may be required to better define its possible utility.

Obstructive left heart disease in neonates with a "borderline" left ventricle: diagnostic challenges to choosing the best outcome

In most newborns with left heart obstruction, the choice between a single-ventricle or biventricular management pathway is clear. However, in some neonates with a "borderline" left ventricle, this decision is difficult. Existing criteria do not reliably identify neonates who will have a good long-term outlook after biventricular repair (BVR). The objective of this study was prospective assessment of the outcome after BVR for newborns in whom the left ventricle (LV) was considered "borderline" by an expert group. This study was a prospective follow-up evaluation of neonates with obstructive left heart disease related to a "borderline" LV who underwent biventricular management between January 2005 and April 2011. Of 154 neonates who required intervention for left heart obstruction, 13 (7.8 %) met the echocardiographic (echo) inclusion criteria. At the first and last echo, the z-scores were respectively -1.76 ± 1.37 and -0.66 ± 1.47 (p = 0.013) for the mitral valve, -1.02 ± 1.57 and -0.23 ± 1.78 (p = 0.056) for the aortic valve, and 13.77 ± 5.8 and 20.85 ± 8.9 ml/m(2) (p = 0.006) for the LV end-diastolic volume. At this writing, all 12 survivors are clinically well. However, LV diastolic dysfunction and pulmonary artery hypertension was present in 5 (36 %) of 12 patients. Endocardial fibroelastosis (EFE) was detected in five patients at the last follow-up echo, but only in two patients preoperatively. Cardiac magnetic resonance imaging did not confirm EFE in any of assessed patients. The study authors could not reliably predict the outcome after BVR for neonates with left heart obstruction and a "borderline" LV. The presence of EFE with consequent diastolic dysfunction is more important than LV volume in determining the outcome. Prospective identification of EFE remains challenging.

Neonatal Surgical Aortic Commissurotomy: Predictors of Outcome and Long-Term Results

BACKGROUND

The objective of this study was to review our institutional experience concerning neonatal aortic commissurotomy and to identify predictors of outcome.

METHODS

From January 1, 1990, to January 1, 2005, 65 neonates were referred for critical aortic stenosis. Among these 36 consecutive patients underwent surgical valvotomy by the same surgeon and 16 patients had balloon valvotomy. We examined clinical records to establish determinants of outcome and illustrate long-term results.

RESULTS

In the surgical group 6 patients had nonstenotic parachute mitral valve, 6 had aortic coarctation, 13 had endocardial fibroelastosis; and 15 had depressed fractional shortening. In the balloon valvotomy group most infants had associated mitral stenosis (n = 7), small aortic annulus (n = 5), multiple anomalies (n = 2), endocardial fibroelastosis (n = 9), and depressed fractional shortening (n = 13). In the surgical group global mortality was 19%; 47% in infants with depressed fractional shortening and 0% in infants with normal fractional shortening. Mortality in the balloon valvotomy group was 56%. Low fractional shortening, low mean aortic gradient, endocardial fibroelastosis, and small aortic annulus were associated with fatal outcome. In the surgical group 6 patients needed Ross operation at a median interval of 4 years from commissurotomy. In the balloon valvotomy group 3 patients needed early mitral replacement and 5 aortic valve surgery. At a median follow-up of 6 years, all children are in New York Heart Association class I, all have a normal ventricular function, 2 have aortic restenosis, and 5 have at least moderate aortic incompetence.

CONCLUSIONS

In a selected population of neonates with isolated aortic stenosis, surgical valvotomy offers an excellent long-term outcome to patients with a normokinetic left ventricle, while patients with a hypokinetic left ventricle have a poor outcome. Balloon valvotomy offers poor results when performed in patients with complex anomalies.

Current treatments for congenital aortic stenosis

PURPOSE OF REVIEW

Congenital valvar aortic stenosis is a challenging disease that often requires repeated palliative procedures. Stenosis can range from mild and asymptomatic, not requiring intervention, to severe, as seen in hypoplastic left heart syndrome. New advances such as fetal balloon valvuloplasty, improvements in the Ross technique, and long-term studies of trans-catheter balloon valvuloplasty and surgical valvotomy warrant a review of the outcomes and optimal timing of the various interventions.

RECENT FINDINGS

Fetal balloon valvuloplasty has shown promise. Despite some mortality and morbidity, some fetuses are showing significant growth in left ventricular structures, allowing biventricular repair. In neonates and infants with congenital aortic stenosis, excellent initial results are obtained with trans-catheter balloon valvuloplasty, although stenosis resistant to further balloon dilation or regurgitation may develop, necessitating surgical intervention. Midterm results from the Ross procedure are encouraging, demonstrating low rates of mortality, aortic insufficiency and re-intervention. Stenosis of the pulmonary allograft may be inevitable, and recent long-term follow-up suggests an increase in aortic insufficiency.

SUMMARY

While availability of fetal balloon valvuloplasty is limited, it has promise for promoting in-utero left ventricle growth and improving function. The optimal procedure for infants and neonates is trans-catheter balloon valvuloplasty. For older patients, the Ross procedure is the repair of choice, although more long-term studies are needed to assess the natural course of the autograft. Outcomes should improve with advances in pulmonary allografts.