UT-H Nurse Researchers Look at Cardiovascular Risks Over Lifetime

In three different research protocols, nurse researchers at The University of Texas-Houston Health Science Center School of Nursing are studying the risk factors for hypertension (or high blood pressure) in different age groups, and the management of the disease. Those groups - adolescents, adults with stage one healthy hypertension, and older adults already diagnosed with cardiac disease - offer an "across the lifespan" look at hypertension. The three research protocols focus on not only risk factors but intervention strategies.

In one study, lead investigator Dr. Janet C. Meininger and colleagues from the nursing school and UT-H School of Public Health and UT-H Medical School have examined adolescents' blood pressures. Adolescence - "a critical period of biologic, social and psychological development, and a pivotal transition in the evolution of risk for hypertension," as stated in an abstract of the study - allowed the researchers to look at several interesting factors which may have an effect on the development of early hypertension: gender, ethnicity, body fat, maturity and management of stressful feelings and situations. Most important to their study was the "linkage" of emotions to elevated blood pressure. Overall, participants in the study reported many more "positive" moods than "negative."

For each of the 385 middle school- and high school-aged children, blood pressure (BP) was monitored for a single 24-hour period, which included school time; BP was taken at 30-minute intervals.

Dr. Meininger, the Lee and Joseph D. Jamail Distinguished Professor, Nursing Systems and Technology, at the School of Nursing, also included in the study protocol a single interview session when the adolescent discussed situations which caused anger or stress and talked about the events in a typical day of his or her life. Blood pressure was measured during the interview session.

"We felt that if we could capture the responses to stressful situations during the interview, we could have a way of identifying adolescents whose blood pressures rose during the day," says Dr. Meininger. The "predictor" was compared to the overall BP average of the 24-hour period. Important for future work is the fact that blood pressure measured during the interview predicted 24-hour blood pressure.

"The goal of the study is, of course, to be able to identify those adolescents who could benefit from an intervention strategy," says Dr. Meininger. "We know from large epidemiological studies that older adolescents who tend to have elevated blood pressure are more likely to develop hypertension, and that hypertension is a disease which leads to heart attacks, strokes, kidney disease.

"We think of adolescence as a very important - critical - time to not just evaluate a young person's likelihood of becoming hypertensive, but to also offer ways of avoiding having hypertension as an adult.

The researchers also note that during adolescence there are some key variables which can affect blood pressure - height, body fat and body fat distribution, and maturity. Thorough evaluations of sexual maturity will help the researchers decipher additional data. This is complicated by the simple fact that there is considerable variance in maturity even for adolescents of the same age.

"I think most of us have felt that adolescence is a difficult time, a time filled with stress, acting out, anger," says Dr, Meininger. "In truth, we saw more `positive' emotions such as a feeling of being relaxed, having a sense of accomplishment or being interested in an activity. The lowest blood pressures were recorded when our students were feeling relaxed or bored."

High blood pressure in a young person can develop into stage 1 hypertension, defined as a systolic blood pressure reading between 140-159 and a diastolic reading between 90-99. A 35-year-old who ignores this kind of hypertension faces a grave risk of vascular disease, heart attack and stroke later in life. A second study originating in the UT-Houston School of Nursing is focusing on intervention strategies for people with stage 1 hypertension. Dr. Patricia Leihr, associate professor, nursing systems and technology, believes that hypertensive patients can learn to control their blood pressure through breathing exercises and simply learning to slow down their speech and movements. Her research protocol also utilizes nutrition counseling and an exercise program.

Dr. Liehr's study - co-investigators are Dr. Meininger and Dr. Robert Volger from the School of Nursing, Dr. Wenyaw Chan from the UT-H School of Public Health, and Drs. Carlos Herrera and Francisco Fuentes of the UT-H Medical School - focuses on adult patients ages 30-50. An eight-week baseline period is followed by an eight-week period of intervention. During the intervention period, patients meet with a dietician who provides nutrition counseling and an exercise physiologist who outlines a sensible plan for exercise. Importantly, the hypertensive patients talk with advance practice nurses about their lives - while watching their blood pressure readings on a computer screen. They are able to see what elevates their blood pressure.

"We'll ask: `What was it about what you just said that made your blood pressure go up?'" says Dr. Liehr. "After a time, our participants will recognize those things which cause stress, and our nurses can help them speak more slowly and generally adapt more calmly to a stressful topic." What the nurses and patients are doing is called "stress modulation."

"We are testing to see if stress management sessions combined with nutrition counseling and exercise lowers high blood pressure more than just the exercise and nutrition counseling together," says Dr. Liehr.

The stress intervention part of Dr. Liehr's research protocol has been an interest for most of her career. "We can teach a person - in an outpatient setting - to recognize when their blood pressure is elevated and, through relaxation strategies, how to control it."

A third research protocol designed by a doctoral candidate at UT-Houston School of Nursing is looking at middle-aged and elderly patients with cardiovascular disease; several of the participants in this study have had major cardiac events, and all of the participants are taking anti-hypertensive medication. A similar model to the "stress modulation" in Dr. Liehr's study is utilized, this model focusing on subjects as they talked about their daily lives and their health concerns. Cardiovascular "reactivity" was measured (high, medium or low) during the talking sessions; as expected, blood pressure was elevated during the health concerns part of discussions. Patients experienced an abrupt change (elevation) in BP, linked to the stress of discussing their health concerns. In the pilot study, average ambulatory blood pressure "loads" (percentage of hypertensive episodes) were predicted from the measurements taken during the discussion sessions. The pilot study - with Lorraine Frazier, a doctoral candidate in the UT-Houston nursing program serving as principal investigator - will almost surely lead to a longer study looking at management of changes in ambulatory BP throughout the day in patients with cardiovascular disease.

"These research protocols are already telling us interesting things about risk factors for development of hypertension, and how to manage hypertension," says Dr. Meininger. "Of course the exciting part of the research is that nurses and nurse practitioners can use these findings in the community and clinical settings, working directly with individuals with hypertension and those at risk of developing it."

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©2006 Texas Medical Center

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