JMIR Publications

ABSTRACT

Background:

In individuals with spinal cord injury or disease (SCI/D) at or above the sixth thoracic segment (Th6), stimuli from both the urogenital and gastrointestinal tract can trigger an uncontrolled response of the autonomic nervous system called autonomic dysreflexia (AD). AD is characterized by hypertensive episodes, which can occur multiple times a day, and may lead to life-threatening conditions like brain hemorrhage. While the short-term consequences of this condition have been in the focus of research, its long-term consequences remain poorly understood. For instance, recurrent hypertensive episodes may contribute to pathophysiological cardiovascular adaptations, including left heart remodeling, such as left ventricular hypertrophy. In turn, left ventricular hypertrophy is associated with an increased risk of cardiovascular morbidity and may contribute to the high burden of cardiovascular diseases observed among individuals with long-term SCI/D, which represent a leading cause of mortality in this population.

Objective:

The primary aim is to characterize differences in left heart remodeling between individuals with high-level (>Th6) SCI/D and AD and individuals with low-level (

Methods:

A cross-sectional study will be conducted among 48 participants equally distributed into two groups, and matched for sex and SCI/D duration: 1) individuals with high-level SCI/D and AD and 2) individuals with low-level SCI/D without AD. All participants will undergo cardiac magnetic resonance imaging (CMR) and measurement of NT-proB-type natriuretic peptide (BNP) concentration in the blood to assess cardiac morphology and function. Differences in CMR parameters and serum NT-proBNP levels between the two groups will be examined using mixed-effects linear regression analyses, adjusted for age and physical activity as potential confounders, and with a random term for matched pairs (sex and SCI/D duration). Additionally, linear multiple regression analyses will also be used to investigate the effects of sex, age and physical activity on the CMR parameters and NT-proBNP levels.

Results:

We anticipate identifying reduced left ventricular end-diastolic volumes and alterationsin other cardiovascular parameters in individuals with high-level SCI/D and AD. Our findings will provide important insights into determining whether screening for left heart remodeling is necessary among individuals with long-term, high-level SCI/D and AD. Furthermore, our results may highlight the potential importance of preventing AD episodes, particularly those triggered by urogenital stimuli, which account for approximately 80% of AD episodes. Reducing the frequency of AD episodes may represent a potential strategy to mitigate cardiovascular burden and improve long-term health outcomes in this population.

Conclusions:

The presented study protocol addresses a clinically relevant but largely unexplored topic. Cardiac remodeling through reccurrent hypertensive episodes induced by AD might be a major hidden risk for premature heart failure and ultimately death. Clinical Trial: The study has been registered with clinicaltrials.gov (NCT07456722) and approved by the ethics committee of Northwestern and Central Switzerland (BASEC-Nr. 2026-00701).