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This Article Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Giulio Rizzoli Alessandro Mazzucco Maurizio Rubino Vincenzo Tursi Domenico Scalia Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Rizzoli, G. Articles by Scalia, D. Search for Related Content PubMed Articles by Rizzoli, G. Articles by Scalia, D.

J Thorac Cardiovasc Surg 1994;107:1369-1370
© 1994 Mosby, Inc.

LETTERS TO THE EDITOR

Atrioventricular canal with Down syndrome or normal chromosomes: Distinct prognosis with surgical management?

Istituto Chirurgia Cardiovascolare Università di Padova^a
Via Giustiniani 2
35100 Padova, Italy

Reply to the Editor:

We appreciate the comments by Drs. Di Carlo and Marino on our article. They seem to endorse our conclusion on the favorable impact of surgical repair of atrioventricular canal (AVC) malformations in patients with Down syndrome. However, when comparing results between patients with and without Down syndrome, they speculate on the alleged effect of more complex anatomic varieties in the latter. Indeed, prevalence of left-sided obstructive lesions, common valve dysplasia, and right ventricular dominance has been reported in the literature in patients with AVC but without Down syndrome.

Prevalence of congenital malformations depends on survival to birth and to diagnosis which, in the setting of chromosomal syndromes, is biased by local abortion policies and by therapeutic determination. It is therefore not surprising that in our surgical study we found an identical prevalence of associated lesions (patent ductus arteriosus excluded) in patients without Down syndrome (20/127) and in those with Down syndrome (16/94).

Di Carlo and Marino suggest that the selection produced by evaluating only the patients who had definitive repair might have excluded the most complex cases. We can accept the fact that an occasional patient with an extreme degree of left or right ventricular hypoplasia has been switched to alternative forms of surgical therapy, but this is true for both groups. As a general rule, every patient with AVC malformation who was brought to our attention was referred for repair.

In addition, we would reiterate that the prevalence of right ventricular dominance in patients with normal chromosomal patterns is equaled by the higher prevalence of left ventricular dominance in patients with Down syndrome. However, at least in our earlier experience, ¹ left ventricular dominance was a significant incremental risk factor for surgical death after repair at multivariate analysis.

In this article ² pooling of associated lesions (patent ductus arteriosus excluded) was not informative because of the nondifferential misclassification effect, ³ whereas the evaluation of selected types of associated lesions was beyond the scope of our investigation and requires a multicentric study to reduce the sparseness of data and the instability of the estimates.

On the basis of our data we can only disagree with the final conclusion expressed by Di Carlo and Marino that "complex anatomic types of AVC are more common in patients with normal chromosomes; these forms carry a less favorable early and mid-term prognosis."

Even though, as we indicated, there seems to be a trend toward fewer reoperations and better postoperative functional indexes in patients with Down syndrome, most of these differences are not statistically evident.

We would therefore reconfirm our conclusion that repair of AVC in patients with Down syndrome has a beneficial effect on survival of this group, but we would be hesitant to propose a higher risk for the genetically normal population.

References

1. Rizzoli G, Mazzucco A, Brumana T, et al. Operative risk of correction of atrioventricular septal defects. Br Heart J 1984;52:258-65.[Abstract/Free Full Text]
   
2. Rizzoli G, Mazzucco A, Maizza F, et al. Does Down syndrome affect prognosis of surgically managed atrioventricular canal defects? J THORAC CARDIOVASC SURG 1992;104:945-53.[Abstract]
   
3. Rothman KJ. Objectives of epidemiologic study design. In: Modern epidemiology. Boston: Little Brown, 1986:77-97.
   

This Article Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Giulio Rizzoli Alessandro Mazzucco Maurizio Rubino Vincenzo Tursi Domenico Scalia Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Rizzoli, G. Articles by Scalia, D. Search for Related Content PubMed Articles by Rizzoli, G. Articles by Scalia, D.