“Late Functional Status of a cohort of Survivors with Critical Aortic Stenosis: A Congenital Heart Surgeons Society Study”

Doctor's Name: 
Brian W. McCrindle, M.D., MPH
The Hospital for Sick Children, Toronto

Sometimes the connection between the left side of the heart that collects up oxygenated blood from the lungs is tightly narrowed. We call this condition critical aortic valve stenosis (critical AS). Critical AS is very rare, but is a heart defect that carries a high risk of death and is difficult to treat. Often, besides the blockage, the left side of the heart (the portions of the heart immediately upstream or downstream of the narrowed portion) is too small or is not normally formed. Not all critical AS patients are the same and there are several different interventions that can be performed for treatment, which can make decisions on how best to treat the condition very difficult. Some patients have such severe problems with the left side of the heart that their hearts cannot be repaired to ensure that they have two usable pumping chambers; we call the operations that these patients must have the single or one ventricle (pumping chamber) Fontan procedure approach. Also, some patients may have few problems with the rest of their left heart, and they can be repaired so that both pumping chambers are used as they were intended to be used. However, some patients fall between these two ends of the spectrum and they could theoretically be treated with either a univentricular or biventricular repair. Doctors do not currently know which approach is best for these indeterminate patients. We have done previous research studies that have shown that when you customize the repair approach to the degree of associated left heart problems, this gives the best survival for everyone with critical AS. However, we do not know how our decisions aimed at maximizing survival may affect how these patients will function in the long-term, particularly in the patients in the “gray zone” where we are unsure which repair would be superior. Therefore, the purpose of our study is to look at survivors with critical AS who have had different types of heart surgeries as to how they are doing regarding their ability to exercise and their overall physical and emotional functioning. This will be the first research study to look at these types of issues in patients who have survived repair of critical AS. The results of the study will be very important to help patients and doctors to decide how best to treat a patient with critical AS, and it will give doctors information to tell patients and their parents how their physical and emotional status will be in the future (what they are expected to be able to do and what problems they may face in the future with sports, school, socializing and other activities).

Methods: The Congenital Heart Surgeons Society (CHSS) is an organization of experienced, accomplished heart surgeons who specialize in the repair of patients with heart birth defects, and includes surgeons from children’s hospitals all over North America. These surgeons are very interested in doing research studies that will help them in their decisions about how to repair certain heart birth defects, and help them in improving their surgical techniques. The CHSS had done a previous research study that has looked at a group of patients with critical AS who were born between January 1194 and February 2000. We now want to study how well these patients are doing now that they are getting older. We will contact all of these patients who are known to be alive, and ask them some questions about their current health problems, and get the medical record information from those doctors who have taken care of them, either now or in the past. If they agree to participate in this study, we will have these patients complete some questionnaires about how well they are functioning, and then have them do an exercise test on a treadmill or bike. The exercise test will tell us how fit they are for exercise. The results of the questionnaires and the exercise test will then be examined to find out how well these critical AS patients feel they are doing, to find out how patients view themselves in comparison to how they do on an exercise test, and to find out what patient and treatment features affect these results.

Relevance: The new information from this important research study will help the heart specialists and surgeons who take care of critical AS patients to:

-        make decisions as to what is the best way to repair their heart problems that are not just based on survival, but also based on how well the patient will do in the future from the perspective of how well they would feel they  function and how well they can actually do on an exercise test;

-        talk to patients with critical AS and their families and give a long-term outlook that is both true and customized for a particular patient;

-        know how the ability to exercise is related to how functional the patient sees themselves.

This will be a unique study, because the CHSS is in an ideal position to enroll the largest ever number of patients into the study and the CHSS has a proven track record in analyzing these questionnaires and exercise tests to determine what the best treatments are for patients with critical AS. This study will help to lead the way toward improvements in care, and will help to find those critical AS patients who are most likely to get the most out of a program designed to give them some rehabilitation to improve how well they are doing.

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