When it Comes to Heart Surgery Sometimes Quantity is Quality

by Drew Heyding on March 8, 2012

Recently CNN covered the story of a baby born with heterotaxy syndrome, a rare condition that is often associated with complex congenital heart defects. The baby was treated in a major pediatric medical center in the Midwest. He underwent heart surgery but several months after his birth remained in the intensive care unit in a precarious condition waiting for another surgery.

National Institutes of Health

His mother learned that some hospitals had more experience treating and operating on babies with heterotaxy. Her initial effort to move her son to Children’s Hospital Boston, one of these hospitals, was unsuccessful. As the CNN story explains, Medicaid would not pay for her son to be transferred out of state to a more experienced hospital. Ultimately she was able to bring her son to Boston with the help of social media and the congenital heart disease community. Does it make sense to travel across the country in a situation like this?

Many medical centers in the United States perform congenital heart surgery and great outcomes happen everyday across the country because of the skill and dedication of the medical teams at these hospitals. But some of these hospitals have higher surgical volumes (meaning they perform more operations than the others). And new research in the journal Pediatrics supports prior studies that have shown that these high volume medical centers give some children with heart defects a better chance of survival.

As far back as the 1970s studies had begun to identify a link between higher mortality (more deaths) and low surgical volume (less experience with a particular operation). This early research focused on adult surgeries. More recently, studies have looked at surgical mortality rates among children.  Much of this research has explored the impact of surgical volume on mortality rates among children operated on for congenital heart disease.

Some studies have focused on specific operations that are especially complicated. Children born with a type of heart defect called hypoplastic left heart syndrome require several surgeries done in sequence. The first operation is called the Norwood procedure.  One study in 2005 and another in 2008 found that survival rates after this procedure were higher in hospitals that performed the operation more often.

Other studies have looked at overall pediatric cardiac surgery mortality data. A study in 2009 used a national database to explore the link between volume and mortality more closely. This research made sure to take into account any imbalance in patient-level risk factors (how sick the children were before their operations) and surgical case mix (how many straightforward versus complex surgeries a hospital did).  These adjustments helped ensure that the comparisons among different hospitals were valid. The researchers concluded that when an operation was especially complex, more children survived the surgery if the child was treated in a high volume hospital.

The newest study published last month in Pediatrics uses more recent data from the same national database. The authors were interested in better understanding the reasons why low surgical volume is linked with higher mortality in congenital heart surgery. The study used data from 2006 to 2009 that included a total of 35,776 patients.

The lowest volume hospitals were defined as centers that operated on less than 150 heart defect cases per year. The highest volume centers operated on more than 350.  Surgeries were classified based on an established risk stratification system (where 1 represents the operation with the lowest risk of death and 5 the highest). Patient characteristics were collected including information on any individual risk factors present before the operation.

Data analysis showed that children who underwent a high risk surgery (category 4 or 5) had higher death rates at a low volume center. The odds of dying in the lowest volume center were 1.86 times higher than the odds of dying in the highest volume center. (There was no difference in mortality rates related to surgical volume when the surgery was low or medium risk).

Low volume hospitals did not have more complications than high volume hospitals. Complication rates may be unrelated to surgical volume because they are tied directly to patient related risk factors. (For example, an infant with lung and kidney problems in addition to a heart defect is more likely to develop a complication than an infant who has no other organ involvement besides the heart regardless of where they have surgery.)

But patients who did have a complication were more likely to die if they were in a low volume hospital than a high volume hospital. (This phenomenon has been observed in research on adult surgery outcomes and termed “failure to rescue”.) A hospital that performs more heart surgeries will gain more experience. Their medical teams will recognize complications more promptly and treat them more effectively because of this experience.

This new research supports health policy that would promote regionalization of specialized surgical services. (Meaning certain hospitals would be designated to care for babies who require surgery for complex heart defects like those associated with heterotaxy and hypoplastic left heart syndromes).

Right now parents often have different hospitals to choose from. Because the closest option may not always be the best, parents of infants and children who will require high risk congenital heart surgery should be informed of the connection between high surgical volume and survival rates.

Kristen March 8, 2012 at 12:33 pm

Absolutely amazing insite! Thank you so much for this fabulous article.

Rosa M. March 8, 2012 at 1:08 pm

So many good points raised here that can also extrapolate to the US health care system in general, but in this case even more serious, when lack of information, mismanaged insurance plans or geography can prove fatal. Let’s hope that the broader audience that CNN provides and well research blog posts like yours raise more and more awareness and those percentages can be lowered to a minimum. I also applaud the CDH community, truly social media at its best

Erin Ayscue March 8, 2012 at 1:48 pm

Wonderful article! This information is so important for the CHD community. Thanks for sharing the data in a way that’s easy for people to understand, as often times data and info like this can be confusing. Fantastic!

Amanda Rose Adams March 8, 2012 at 2:03 pm

Other considerations are the investment in their nursing staff and training. The higher volume facilities are more likely to invest in a dedicated cardiac ICU above a standard PICU/NICU in smaller centers and are more likely to invest in training and retaining a top flight post op nursing program both in the CICU but in a cardiac step-down unit.

Any children’s hospital that routinely has the same nurses treating cancer patients, accident patients, and cardiac patients is not targeting expertise as effectively. Each child should receive the best possible care for his/her condition, and the hospitals who know this and act on it will have better outcomes. It’s about the doctors, but it’s also about the nurses, the techs, the staff management, and the responsible use of resources.

Oh, and I am NOT a nurse, I’m the mother of a child whose had 12 heart surgeries and the author of a book about those experiences. But I LOVE good nurses and hospitals who get it right.

Drew Heyding March 9, 2012 at 3:58 pm

Great points. There are likely multiple factors that drive the relationship between surgical volume and post-operative mortality rates. It is not just about the surgery or the surgeon. A dedicated cardiac care unit along with a team of health providers (nurses, respiratory therapists and others) who have experience with post-operative care of complex congenital heart patients are both important factors in surgical outcome.

The authors of the Pediatrics study point out potential factors that may lead to failure to rescue, including “differences in training and availability of personnel, and hospital structure, processes, and management practices.” The next step is to characterize these kind of factors more precisely and apply what is learned.

Helen Chang March 9, 2012 at 10:51 pm

I am a nurse, and what’s more, an OR nurse. At my place of employment, we have a team approach to providing care. This includes surgeons, anesthesiologists, nurses, perioperative techs, and instrument specialists. Because of the team approach, we specialize in a certain field of surgery. This leads to greater expertise in that field, and greater expertise leads to greater flexibility in providing patient care. We’re also working hard to make everyone feel equally important, with an equal voice in what goes on in the OR. It’s not a perfect system yet, and probably always will need adjustment, but our intra-team communication has definitely improved over the last year and this is leading, I believe, to better patient outcomes. What one member of the team misses, another may see, and if that person is comfortable in speaking out, the patient benefits.

Jessamyn Fields March 8, 2012 at 5:28 pm

Thank you, this is about my son Pierce :-)

Angela March 8, 2012 at 10:22 pm

Thank you for the post! Would add a definition of heterotaxy syndrome or a link to an explanation (not everyone will be able to load the CNN video), but otherwise it flows well! Found the result (the high volume being better) interesting.

Drew Heyding March 9, 2012 at 3:45 pm

Thank you for the feedback. Good point about the CNN video. I had not thought of the difficulty those outside the United States would run into with this link. This site is a great place for background on heterotaxy syndrome.

Simon Packer March 9, 2012 at 7:08 am

Very interesting read. Do you think that as well as experience, it could be about flow of resources? What I mean by this is: if you have a hospital that is doing lots of surgeries it would be a bigger hospital which is generating more money and therefore attracts better doctors? These better, more skilful doctors, dont only get more experience but they are better surgeons in the first place. Therefore it maybe less about experience but actually more about the doctors skill in doing the surgery and the resources provided by the hospital for that doctor. I think this relates a bit to Tudor Hart’s inverse care law. Thanks for the read.


Tina March 9, 2012 at 11:19 am

Thank you for taking the time to research and write this article. Not a day goes by that I am not thankful to live near what is considered one of the best Children’s Hospitals in the country. When you are talking about the life of your child . . . you want to be able to bring them to the best nurses, doctors and surgeons.

Eric Greenwood March 9, 2012 at 1:48 pm

Very cool study – fascinating data!

Maria P March 10, 2012 at 9:08 am

Thank you for writing about such an important topic. Unfortunately a percentage of children die because they are born in the wrong center, meaning a center with low volumes and limited expertise with the complications that may arise from the surgery or the surgery itself. The surgery is only part of the success factors, a good post-op care in a specialized unit with a knowledgeable team are crucial when dealing with complex heart defects. I wish hospitals that are not capable of conducting such surgeries and caring for the patient referred to bigger centers instead of attempting something bigger than them that most likely will end up with a bad outcome.

Denise March 10, 2012 at 11:55 am

Thank you for writing about this. Our grandson was well taken care of in a Florida hospital , however, when he needed life saving surgery in Boston ( born with Hypolplastic Left Heart Syndrome) , his insurance would not pay enough for his transport to Chidren’s Boston. Our family had to put $21000 on credit card. Now out of ICU, he needs to stay close by , so we are all helping with a small apt. We need better resources out there for families regarding transport & housing if children must live for awhile close to these specialized hospitals. Thank you for your work & I pray this is just the beginning of an awareness campaign.

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