Quantification of morbidity associated with congenital heart surgery

The objective of this study was to estimate the morbidity according to observed complications after congenital heart surgery over 1-year period.

The previously established list of conditions prone to affect patients' well-being or increase cost of in-hospital stays was used systematically to score the severity of postoperative complications from 1 to 4 points. The morbidity score was calculated by adding the scores of observed complications. When the sum amounted to more than 5 points, a morbidity score of only 5 points was attributed. If no complication was detected, a score of 0.5 points was assigned. The resulting morbidity scores were correlated with the length of stay in the intensive care unit (ICU) and in the hospital, the duration of mechanical ventilation, and Aristotle complexity scores.

A total of 542 primary procedures performed in the year 2011 were studied. Aristotle basic and comprehensive scores amounted to 7.78 ± 2.65 and 10.15 ± 3.83, respectively. Mortality was 1.85% (10/542). The standardized ratio of surgical performance reached 103.10%. Total cavopulmonary connection with extracardiac fenestrated conduit constituted the most frequent operation (n = 34). No complication was observed following 183 (33.8%) procedures. More than two complications were observed in 114 cases (21%). The three most frequent unfavorable conditions were "mechanical ventilation 25 to 95 hours" (n = 150), low cardiac output syndrome (n = 56), and cardiac arrhythmia requiring medication (n = 50). The estimated mean morbidity score amounted to 2.26 ± 1.80 points. Scores ranged from 0.68 ± 0.50 for primary closure of atrial septal defect to 4.50 ± 0.79 for the Norwood procedure. They were perfectly related to the length of ICU stay and to the duration of mechanical ventilation (Spearman coefficient r = 1). Correlation was high with the length of hospital stay (r = 0.83), Aristotle basic score (r = 0.89) (r = 0.96), and comprehensive score (r = 0.94) (C-index = 0.97). The observed mean morbidity score was statistically not different from the expected mean morbidity score according to the basic Aristotle complexity: p = 0.73.

Quantification of morbidity indicates the length of ICU stay and the duration of mechanical ventilation as the best surrogates for morbidity. Such benchmarking and scoring of observed postoperative complications paves the way for an accurate assessment and improvement of quality care in congenital heart surgery.