Definition: Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
Input: Abstract: During the early development of atriopulmonary anastomotic operations (Fontan-Kreutzer), a number of physiologic and anatomical limits were proposed by the Fontan group as selection criteria. Among 167 consecutive patients undergoing modified Fontan procedures from 1973 through 1985, 109 (65%) patients exceeded one or more of the original selection criteria in areas of age, anomalies of systemic or pulmonary venous connection, pulmonary artery distortion, and pulmonary artery pressure. Twenty-six patients had a mean pulmonary artery pressure greater than 15 mm Hg, with 16 operative survivors (62%). Nineteen patients had anomalies of systemic and/or pulmonary venous connection, and 16 survived (84%). There were 44 patients under the age of 4 years, and 26 survived (59%). Twenty-five patients were older than 15 years, and 23 (92%) survived the Fontan procedure. Pulmonary artery distortion, relating to prior palliative operations, was found in 34 patients. Seventeen of these 34 survived a modified Fontan procedure (50%). Twenty-six patients had a pulmonary arteriolar resistance more than 2 Wood units times square meter, and 14 survived (54%), whereas 81 of 93 with a pulmonary arteriolar resistance of less than 2 U X m2 survived (87%). Multivariate analysis showed that pulmonary arteriolar resistance and pulmonary artery distortion had a significant, negative impact on survival, but age and anomalies of systemic and/or pulmonary venous connection did not. Pulmonary artery pressure was not an independent predictor of outcome. The results show that the original criteria may be exceeded in the areas of age and anomalies of pulmonary or systemic venous connection. Pulmonary artery pressure alone should not contraindicate a Fontan procedure if pulmonary arteriolar resistance is low. Pulmonary artery distortion from a prior palliative operation and elevated pulmonary arteriolar resistance increase the risk of a Fontan procedure.

Extending the limits for modified Fontan procedures.