Children's Hospital Colorado

Pediatric Cardiac Surgery Outcomes

We are one of the largest programs in the country treating patients with heart problems from before birth through adulthood, with exceptional outcomes.

Best Children's Hospital by U.S. News & World Report Cardiology 2021-2 Badge

Hearing that your child needs heart surgery can be overwhelming. At the Heart Institute at Children’s Hospital Colorado, our caregivers understand the anxiety and stress that can come with a serious diagnosis. We’re here to guide you throughout your child’s care, from diagnosis to treatment and beyond.

In our history, we’ve cared for thousands of infants, children, teens and even adults with a vast variety of congenital heart defects (CHDs). As the largest pediatric heart surgery program in the region, we perform more than 500 heart surgeries per year. Our highly specialized surgeons take on the most complex heart problems and achieve some of the best outcomes in the nation.

It’s all in support of the measure that matters most: the long and productive lives our patients go on to lead.

What are pediatric cardiac surgery outcomes?

In the medical world, the term “outcomes” means “success rates.” Many – but not all – pediatric cardiology centers measure and report their surgical outcomes to help parents make the best decision about where to take their child for heart surgery.

Here, we evaluate our success by monitoring and comparing our cardiac surgery statistics with other top pediatric hospitals. We also routinely check and publish other quality and patient safety metrics and heart transplant outcomes to ensure that families have the latest information when deciding who should care for their child.

Why transparency matters

We believe that families have the right to know every heart surgery program’s outcomes. Our Heart Institute is the only pediatric heart surgery program in Colorado and one of the few in our region to publicly report our cardiac surgery outcomes data. This transparency is one of the keys to our success as one of the best hospitals for congenital heart surgery in the country.

When researching heart surgery programs, parents should look for multiple outcome measures, such as total survival, survival by surgical complexity and length of stay, and consider these statistics together. No single metric should stand alone.

View some of the many things we measure and see our latest outcomes data below.

Open heart surgery survival rates

Heart surgery programs typically report their overall survival rate as well as survival rates based on the complexity of the surgery.

What we measure:

The percentage of heart surgery patients who survive their open heart surgery.

At Children’s Colorado, our overall survival rate for all cardiac surgery patients, regardless of how complex the surgeries are, is 97.2%. This is the same as the national average.

97.2% Cardiac surgery survival rate at Children's Colorado

Source: Internal data, July 2015 through June 2020

What it means:

Having a higher survival rate indicates that a pediatric heart center is more experienced and better equipped for congenital heart surgery, and that fewer patients pass away during or after surgery.

Some heart centers take more complicated cases than others, which is why it’s important to also compare survival rates by complexity and type of defect.

Cardiac surgery survival rates by complexity

Some congenital heart defects are more complex than others. And because there are so many types of heart defects, no pediatric heart program will see the exact same defects each year.

The Society of Thoracic Surgeons (STS), the organization with the largest congenital heart surgery database, organizes the types of surgeries into five categories, which are referred to as “STAT categories” so they are easier to compare.

What are STAT categories?

STAT categories classify heart surgeries into groups based on how risky or complex they are. The STAT 1 category indicates surgeries with the lowest risk of death, while the STAT 5 category indicates the surgeries with the highest risk of death. A hospital that has a high survival rate for STAT 5 cases indicates success at handling unpredictable situations during the operation and during recovery.

What we measure:

STAT 5 neonatal survival measures the percentage of babies with the most complex heart defects who survive their surgery and have been discharged from the hospital.


What it means:

At Children’s Colorado, our surgical team specializes in some of the most complex cardiovascular procedures, with special expertise in surgical repair during the newborn period. Having a high STAT 5 survival rate means that the newborn babies we treat are more likely to survive their operation than the national average, even though we accept many more complex patients.

Measuring congenital cardiac surgery survival

Open heart surgeries can be risky, and some deaths and complications are inevitable. Unfortunately, no program has a 100% survival rate. When researching a pediatric heart surgery center, it’s also important to compare the survival rate by patient age, type of operation and STAT category (complexity). This is because these rates can be much different than the program’s overall survival rate.

Newborn cardiac surgery survival

Performing heart surgery on newborn babies is more challenging due to the young age and small size of the patients. By comparing newborn survival rates along with STAT category, parents can get an idea of how well the surgeons perform in the most challenging cases.

What we measure:

We compare our survival rates for newborn patients with national averages by the complexity of the surgery.


What it means:

At Children’s Colorado, our surgeons have extensive experience correcting heart defects in even the youngest patients — some just a few hours old. Our survival rates for STAT 1, STAT 2 and STAT 5 cases are higher than the national averages.

Cardiac surgery survival by procedure

Cardiac surgery programs can also report survival rates by each specific operation. These are called “benchmark operations,” and they are one of the ways surgical centers can compare outcomes. Note that these data do not include a patient’s specific risk factors prior to surgery.

In the table below, we report the total number of benchmark operations at Children’s Colorado, as well as the survival rates here compared to the national average.

What we measure:

Index case survival shows the percentage of patients who received a specific operation and were alive 30 days after their operation. It also includes patients who needed to be in the hospital longer than 30 days who were alive and successfully able to go home.

Index case survival

Type of operation Total operations Children's Colorado Children's Colorado survival
Higher is better (Internal data - July 2016 through June 2020)
National survival (STS)
Higher is better (June 2015 through July 2019 data)
Arterial switch repair 25 96.2% 97.8%
Arterial switch repair + Ventricular septal defect 10 100% 94.8%
Atrioventricular canal defect repair 45 97.8% 97.9%
Glenn / Hemi-fontan 86 97.7% 98.1%
Fontan procedure 71 100% 99.0%
Norwood procedure 60 95% 86.4%
Tetralogy of Fallot repair 57 96.5% 98.9%
Truncus 14 100% 91.8%
Ventricular septal defect repair 122 99.2% 99.5%
Off bypass coarctation of the aorta 110 98.2% 98.8%

What it means:

For the majority of the open-heart surgeries listed above, our survival rates are higher than the national average.

It is challenging to compare outcomes by procedure alone. The procedure-alone data does not include important health-related factors such as age, other health conditions (called comorbidities), and genetic conditions that can make procedures riskier. This is why pediatric heart surgery programs should report a wide range of outcomes, including how well patients do when they are at higher risk due to other health conditions.

Risk-adjusted cardiac surgery survival rates

To help compare programs, the STS reports what are called “risk-adjusted” rates. This is a statistical evaluation developed by STS that predicts a patient’s risk of undergoing surgery. This evaluation attempts to include patient-related risk factors prior to surgery, such as age, weight and genetic abnormalities, in addition to the patient’s surgical risk. Using this method, STS compares the actual patient outcomes (observed outcomes) to expected outcomes (those predicted by the statistical model). Ultimately, a heart center should strive to have observed survival rates that are the same or higher than the expected survival rates.

The most recent data from STS has been delayed due to the STS team changing their data warehouse and reporting analysis. We will update this important information as soon as the next STS data release is available.

Survival by STAT category

What we can measure while waiting for updated STS data:

There are five STAT categories for congenital heart surgeries and they are based on the likelihood of mortality with STAT 1 having the lowest chance and STAT 5 having the highest chance. We are able to compare our current STAT category surgery survival with the outcomes from the latest STS release.


What it means:

For the highest risk surgeries (STAT 5), we perform consistently better than the expected outcome and the national average.

Average length of stay

By comparing the average length of stay between hospitals, parents can learn which programs are best equipped to care for their child. The longer a child stays in the hospital after surgery, the more likely they are to have complications.

What we measure:

The chart below shows the average number of days that children stay in the hospital for heart surgery by benchmark procedure.

Adjusted days Observed days Expected O/E ratio Confidence intervals
15.5 days 13.9 days 14.7 days 0.95 days Cl 12.2 - 18.8

What it means:

Our postoperative length of stay (the observed days) is less than expected when considering the complexity of conditions we treat at Children’s Colorado. When comparing our data to other large pediatric surgery programs, we have one of the lowest postoperative hospital lengths-of-stay. The majority of cardiac surgery patients at Children’s Colorado spend less time in the hospital than the national average, indicating that they receive high-quality care before, during and after surgery, which helps them go home sooner.

Pediatric heart surgery volumes

Finally, when it comes to congenital heart surgery, volume matters. Studies show that kids who need heart surgery do better when they are treated by medical teams that perform a high number (or volume) of surgeries. This is because surgeons in high-volume centers get more experience and see a wider range of heart defects than surgeons who perform only a handful of surgeries per year.

Performing hundreds of surgeries each year indicates that the hospital is a high-volume center and is likely to have better patient outcomes. This is particularly true for patients with complex heart defects.

Number of heart surgeries performed at Children’s Colorado

What we measure:

Surgical volume indicates the number of heart surgeries performed at a hospital.


Cardiopulmonary bypass indicates when a patient has to be connected to a machine that does the work of the heart and lungs while surgeons repair the heart. These surgeries are more complex than those without cardiopulmonary bypass.

Cardiac surgery volume

Operation type 2017 2018 2019 2020
Cardio-pulmonary bypass 338 326 375 373
No cardio-pulmonary bypass 119 121 137 191
Other 56 69 86 117
Total 513 516 598 681

What it means:

Children’s Colorado is a high-volume cardiac surgery center, performing more than 500 surgeries each year for patients with congenital heart disease. We also perform hundreds of surgeries with cardiopulmonary bypass each year. This means we have the team, the experience and the facilities to treat kids, teens and even adults with a wide variety of congenital heart defects.

From the operating room to the cath lab

At Children’s Colorado, we’re repairing more heart defects using lower-risk cardiac catheterization instead of open heart surgery.

See how

Provider and patient smiling and talking with each other.

Looking for a second opinion?

From heart conditions present at birth to adult congenital heart disease to heart conditions requiring surgery, our pediatric heart experts can provide a second opinion so you feel confident in your care plan.

Request a second opinion from our Heart Institute

Learn even more about quality and patient safety standards and our heart transplant outcomes at the Heart Institute.

For questions about this data, please call 720-777-6820.