Abstract Body (Do not enter title and authors here): Background: Many of the 1.4 million adults with congenital heart disease (CHD) are lost to follow up (LTF). We aimed to identify factors associated with LTF and compare to those who remained in care.

Methods: In the Congenital Heart Disease Project to Understand Lifelong Survivor Experience (CHD PULSE), we performed a cross-sectional survey in 2021-2023 of CHD survivors with a history of intervention at 11 centers in the Pediatric Cardiac Care Consortium, a large US-based registry of CHD procedures. Participants reported their cardiac history, general health, education, income, health insurance, healthcare utilization, and marital status. LTF was defined as having seen a cardiologist three or more years ago.

Results: Among the 3109 respondents with CHD (median age 33) there were 1157 (37%) LTF and 1952 (63%) in care. Age, sex, marital status, and household income were not risk factors for LTF; but lack of health insurance, lower severity of CHD, and increasing time since last heart surgery were. Notably, respondents who reported being told in adolescence about the lifelong need for a cardiologist were almost three times as likely to report being in care (79% vs 28%, p<0.0001). Among women, most reported no LTF if counseled about concerns with pregnancy or told to avoid pregnancy. The most common reasons for being LTF for 5 years or more (N=857) included feeling well (60%), not thinking there was a need for lifelong care (49%), and a doctor told them they no longer needed to see a cardiologist (47%). Those LTF were more likely to report excellent or very good general health, physical health, and quality of life than those not LTF. There were no differences in self-assessment of mental health between groups.

Conclusion: Adults with CHD and LTF were more likely to report less severe heart defects, a younger age at last surgery and a lack of counseling about the need for lifelong care.