Williams Syndrome: Major Adverse Cardiac Events after Heart Surgery

Approximately 20,000 to 30,000 Americans have Williams syndrome, (WS; chromosome 7 microdeletion). This genetic condition is characterized by multiple problems, including cardiovascular disease, developmental delays, and learning disabilities. However, WS patients often have exceptional verbal abilities, highly social personalities, and musical talent. WS patients often need cardiac surgery, but are at elevated risk for major adverse cardiac events (MACE, defined to include in-hospital mortality, cardiac arrest, or postoperative mechanical circulatory support). Researchers from a number of leading academic facilities across the United States have published a study that details MACE prevalence and risk factors in WS patients. Their study appears ahead of print in the Journal of Thoracic and Cardiovascular Surgery.

The researchers used the Society of Thoracic Surgeons Congenital Heart Surgery Database (2000-2012) to identify patients with WS who had undergone cardiac operations. They classified operations into 4 groups: isolated supravalvular aortic stenosis, complex left ventricular outflow tract (LVOT), isolated right ventricular outflow tract (RVOT), and combined LVOT/RVOT procedures. Then, they identified episodes of MACE and looked for associations with preoperative factors.

The researchers collected data from 87 surgical centers and they identified 447 operations. Patients’ median age was 2.4 years and median weight was 10.6 kg. Five percent of children died (n=20), and 9% (n=41) experienced MACE.

Combined LVOT/RVOT was most closely associated with MACE. Eighteen of the 87 patients (21%) who had this procedure experienced MACE. Complex LVOT procedures also had a high rate of MACE (12 out of 131; 9%). Isolated RVOT procedures were not associated with elevated MACE rates.

As age and weight increased, the likelihood of MACE decreased.

Any preoperative risk factor doubled the risk of MACE, as did procedures involving coronary artery repair.

This study’s strengths are its size and data source. The authors note that details of individual cases, including unusual intraoperative findings that may be unique to WS patients, were not available. While the study provides much needed information about cardiac surgery in Williams syndrome patients, it shows that more detailed data collection could help even more.