With more premature babies surviving, some born as early as 14-16weeks before their due date, long-term cardiac risk factors are developing at a much younger age.
Heart Research Australia has a long-standing relationship with the Neonatology unit of Royal North Shore Hospital Sydney. We have helped provide funding for over 20 years to support researchers in their investigations of various cardiac implications related to premature birth.
Several new diagnostic and therapeutic approaches have emerged from outcomes and insights of previous trials supported by Heart Research Australia. Due to improved practices, even the tiniest of premature patients increasingly survive their initial NICU stay and grow up free from major disabilities.
With more of these babies surviving, they are however, now seen to be developing more longer-term cardiac risk factors such as hypertension as teenagers and young adults at a significantly earlier age than those born at term.
“They do have higher blood pressure, more heart disease, and more kidney disease. There has been speculation as to why that is, and we are now trying to see this while it is happening as these pre-term babies grow. We’ll be able to monitor what is happening with the small blood vessels and we think this is one of the reasons they end up with high blood pressure and heart disease.” – Eveline Staub – Neonatologist
Dr Eveline Staub is investigating hypertension and problems associated with blood vessels in babies currently being born pre-term, to try to understand what is causing these teens and young adults born prematurely to suffer these cardiac risk factors at such a younger age than those born at term. What happens for them in the NICU? What is causing this hypertension in young adults?
Underdevelopment of small blood vessels
Underdevelopment of small blood vessels is a factor leading to increased risk of early onset high blood pressure. There is concern that smallest blood vessels of premature babies do not form properly and thickened blood vessels and atheromas that can obstruct the flow of blood create further risk of heart disease.
Studies of how small blood vessels develop show they don’t grow as well for individuals born pre-term. Evidence of underdeveloped small blood vessels occurs in the whole body. With not enough small blood vessels and others underdeveloped, the heart is required to work harder and generate higher pressure to pump blood around the body. This puts the pre-term individuals at risk of higher blood pressure. Additionally, the strain on the heart muscle due to the increased workload of pumping blood into the too few and too narrow small blood vessels can cause heart failure over time.
In addition to the underdevelopment of the small blood vessels, the walls of the big blood vessels such as the aorta, the main artery in the body, is stiffer in younger adults born pre-term versus those born at term. Again, the heart must work harder to pump against more resistance and causing an additional risk factor for heart disease such as heart attacks or strokes.
This new research study in the Department of Neonatology at Royal North Shore Hospital tracks the development of small blood vessels and blood pressure of premature babies. Over the next three years, approximately 80 preterm and term babies will be followed from birth at different weeks of gestation until age 1. New techniques of ultrasound imaging will be used to trace the blood vessels in the kidneys and aorta, as well as new measurements of blood pressure and kidney function. The hope is for insights from this study to shed light onto the cardiovascular consequences of premature birth. Ultimately, increased knowledge of the contributing factors toward hypertension will help identify the highest risk groups and allow early intervention to prevent later heart disease.
Increased survival rates of premature babies make obvious the late sequelae of prematurity not previously acknowledged. An infant born more than three months early is more than twice as likely to require treatment for arterial hypertension as a young adult, compared to an infant born at term. Even infants born 5-6 weeks early have an increased risk of suffering from hypertension as an adult. This poses a relevant burden of future cardiovascular disease on the individual and the health care system overall, especially amongst cases of unrecognized hypertension in a young adult
Dr Staub and Heart Research Australia are working on increasing awareness for GPs and affected families that those born prematurely require regular monitoring of their blood pressure throughout childhood and into the early adult years. Education is paramount to reduce the risk of developing heart disease. This knowledge of increased hypertension risk for pre-term children and teenagers will help patients and care givers understand the importance of monitoring blood pressure.
For more information on research conducted on the heart health of premature babies click here.