Mortality for Critical Congenital Heart Diseases and Associated Risk Factors in Newborns. A Cohort Study

Abstract Background: Congenital heart diseases are the most common type of congenital defects, and account for more deaths in the first year of life than any other condition, when infectious etiologies are ruled out. Objectives: To evaluate survival, and to identify risk factors in deaths in newborns with critical and/or complex congenital heart disease in the neonatal period. Methods: A cohort study, nested to a randomized case-control, was performed, considering the Confidence Interval of 95% (95% CI) and significance level of 5%, paired by gender of the newborn and maternal age. Case-finding, interviews, medical record analysis, clinical evaluation of pulse oximetry (heart test) and Doppler echocardiogram were performed, as well as survival analysis, and identification of death-related risk factors. Results: The risk factors found were newborns younger than 37 weeks (Relative Risk - RR: 2.89; 95% CI [1.49-5.56]; p = 0.0015), weight of less than 2,500 grams (RR: 2.33 [; 95% CI 1.26-4.29]; p = 0.0068), occurrence of twinning (RR: 11.96 [95% CI 1.43-99.85]; p = 0.022) and presence of comorbidity (RR: 2.27 [95% CI 1.58-3.26]; p < 0.0001). The incidence rate of mortality from congenital heart disease was 81 cases per 100,000 live births. The lethality attributed to critical congenital heart diseases was 64.7%, with proportional mortality of 12.0%. The survival rate at 28 days of life decreased by almost 70% in newborns with congenital heart disease. The main cause of death was cardiogenic shock. Conclusion: Preterm infants with low birth weight and comorbidities presented a higher risk of mortality related to congenital heart diseases. This cohort was extinguished very quickly, signaling the need for greater investment in assistance technology in populations with this profile.

背景：先天性心脏病是最为常见的先天性缺陷类型，在排除感染性病因的前提下，其导致的婴儿第一年死亡数多于其他任何疾病。目的：评估新生儿期重症及/或复杂性先天性心脏病患儿的生存状况，并明确该类新生儿死亡的相关危险因素。方法：本研究为嵌套于随机病例对照研究的队列研究，设定95%置信区间（Confidence Interval, 95% CI）与5%的显著性水平，按新生儿性别与产妇年龄进行匹配。研究开展了病例查找、访谈、病历分析、脉搏血氧饱和度检测（pulse oximetry，心脏检测）的临床评估与多普勒超声心动图（Doppler echocardiogram）检查，同时进行生存分析及死亡相关危险因素的识别。结果：本次鉴定出的危险因素包括：胎龄小于37周的新生儿（相对危险度（Relative Risk, RR）=2.89；95%CI[1.49-5.56]；p=0.0015）、出生体重低于2500克的新生儿（RR=2.33；95%CI[1.26-4.29]；p=0.0068）、双胎妊娠（RR=11.96；95%CI[1.43-99.85]；p=0.022）以及合并基础共病的新生儿（RR=2.27；95%CI[1.58-3.26]；p<0.0001）。先天性心脏病相关死亡率为每10万活产81例。重症先天性心脏病的归因死亡率为64.7%，比例死亡率为12.0%。先天性心脏病新生儿出生28天生存率下降近70%。主要死亡原因为心源性休克。结论：合并低出生体重与共病的早产儿，其先天性心脏病相关死亡风险更高。本队列的随访终止极为迅速，提示针对此类人群需加大辅助诊疗技术的投入力度。