“Masked” pulmonary venous obstruction in patients with isomerism of the right atrial appendages: an overstated association

Abstract

Isomerism of the right atrial appendages is associated with anomalies of pulmonary venous return, which may be obstructive. The associated pulmonary arterial obstruction, however, has been reported to "mask" the pulmonary venous obstruction, with resultant pulmonary edema following augmentation of the flow of blood to the lungs. We postulated that the frequency of "masked" pulmonary venous obstruction has been over-reported in the literature. To ascertain the true situation, we evaluated the frequency of "masked" pulmonary venous obstruction in a large, unselected, group of patients with isomerism of the right atrial appendages. We evaluated the clinical, anatomic, and radiographic data of 65 newborns seen with this syndrome since 1970. Development of pulmonary venous obstruction, both before and after systemic-to-pulmonary shunting and/or infusion of prostaglandin E1, was determined and correlated to clinical and radiographic findings. Of the 65 patients, 19 (29%) were ultimately diagnosed with pulmonary venous obstruction. The pulmonary veins themselves connected in infradiaphragmatic fashion in 10 patients, supracardiac in 3, to the atriums directly in 1, and in mixed fashion in the other 5. Pulmonary venous obstruction was readily apparent in 15 of the 19, as demonstrated by pulmonary edema on initial chest radiography. The remaining four cases ultimately diagnosed with pulmonary venous obstruction received augmentation of pulmonary blood flow with resultant pulmonary edema. Of these four severely cyanosed patients, pulmonary vascular markings on the initial chest radiograph had been normal in one but increased in three. Due to the presence of these clinical markers, they do not truly represent "masked" pulmonary venous obstruction. Except for two patients with minimally obstructed pulmonary arterial blood flow, 44 patients without pulmonary venous obstruction had normal or decreased pulmonary vascular markings at presentation. Of these 44, 14 received infusions of prostaglandin E1, with none developing pulmonary edema. We conclude that pulmonary venous obstruction is usually readily apparent at time of presentation in patients with right isomerism, and that "masked" pulmonary venous is a very rare event which has been over-emphasized in the literature. Careful evaluation of clinical and radiographic findings at time of presentation can correctly identify pulmonary venous obstruction in such patients.

Surgical Management of Hearts with Isomeric Atrial Appendages

“…Optimal management of the two sub-sets remains nebulous. [14][15][16][17][18][19][20][21][22][23][24][25]38 The subsets, nonetheless, are best segregated on the basis of right versus left isomerism. The markedly different features will post different surgical challenges.…”

“…Moderately hypothermic cardiopulmonary bypass at 32°C, using cold blood cardioplegia, is now the most popular technique, replacing continuous cardiopulmonary bypass with low-flow perfusion, brief periods of deep hypothermic circulatory arrest, and deep hypothermic circulatory arrest with selective cerebral perfusion. [14][15][16][17][18][19][20][21][22][23][24][25]38 Venous cannulation can be problematic in both subsets because of the systemic venous anomalies. Direct cannulation is preferred because of the likely complexity of any intraatrial repair.…”

“…The intracardiac anomalies are more likely to be amenable to complete repair in those with left isomerism, with biventricular repairs reported in one-third to one-half of patients. [14][15][16][17][18][19][20][21][22][23][24][25]38 Such repairs, nonetheless, often require complex atrial and ventricular baffle procedures. [14][15][16][17][18][19][20][21][22][23][24][25]38 The complex malformations associated with right isomerism, in contrast, usually preclude biventricular repair.…”

“…[14][15][16][17][18][19][20][21][22][23][24][25]38 Such repairs, nonetheless, often require complex atrial and ventricular baffle procedures. [14][15][16][17][18][19][20][21][22][23][24][25]38 The complex malformations associated with right isomerism, in contrast, usually preclude biventricular repair.…”

Hearts with isomerism of the right atrial appendages – one of the worst forms of disease in 2005

“…More recent data now suggests that such masked pulmonary venous obstruction may be less common than once thought. 142 Failure to define the arrangement of the pulmonary veins preoperatively, nonetheless, results in high surgical mortality, with the findings reported in 2000 by Chowdhury et al 143 providing validation for the concern expressed much earlier by DeLeon et al 144 These observations are further supported by the experience reported by Jenkins et al, 145 showing that, in the setting of totally anomalous pulmonary venous connection, a small sum of the diameters of the individual pulmonary veins, a small confluence, and the presence of heterotaxy syndrome were all significant predictors of survival in univariate analysis. Multivariate analysis showed that the small size of the pulmonary veins was a strong adverse predictor of survival independent of the presence of heterotaxy.…”