Obesity Worsens Clinical Outcomes of Right Ventricular Dysfunction

Researchers published the study covered in this summary on medRxiv as a preprint that has not yet been peer reviewed.

Key Takeaways

In a study of more than 8000 consecutive ambulatory and hospitalized patients with a broad spectrum of cardiopulmonary disease who underwent right heart catheterization in a Boston hospital, obesity and higher body mass index (BMI) were consistently associated with right ventricle (RV) dysfunction.
More importantly, measures of RV dysfunction were associated with increased risks of mortality and heart failure hospitalization during a 7-year follow-up.

Why This Matters

Taken together, the findings underscore the importance of obesity as a risk-enhancing factor for RV failure, with important implications for subsequent adverse outcomes.
The findings are of particular interest given emerging therapies for obesity, including glucagon-like peptide-1 (GLP-1) agonists.
Prior noninvasive echocardiography or cardiac MRI studies demonstrated that obesity is associated with worse RV structure and function; however, accurate standard echocardiographic assessment is challenging due to the complex geometry of the RV and cardiac MRI may not be practical for widespread use.
The invasive hemodynamic indices used in this study allowed for more direct physiologic assessment with prognostic implications.

Study Design

The researchers examined data from 8285 consecutive patients undergoing right heart catheterization between 2005 and 2016 at Massachusetts General Hospital.
The study excluded patients who had an acute myocardial infarction (MI) on the same day, cardiac arrest or shock within 24 hours, mechanical ventilation, intra-aortic balloon pump, history of heart or lung transplant, complicated adult congenital heart disease or history of valve replacement as well as patients on dialysis or with missing key data.

Key Results

Patients were a mean age of 63 years and 39% were women.
Comorbidities included hypertension (59%), diabetes (23%), chronic lung disease (16%), obstructive sleep apnea (14%), previous MI (19%), and previous heart failure (32%).
Patients had a mean BMI of 29.3 kg/m²; 28% were of normal weight, and the rest had overweight (34%), obesity class 1 (21%), or obesity class 2-3 (17%).
Over 7.3 years of follow-up, 3006 patients died and 2004 patients were hospitalized for heart failure.
Higher BMI was associated with the following worse measures of RV hemodynamic function:
- Lower pulmonary artery pulsatility index (PAPi)
- Higher right atrial pressure to pulmonary capillary wedge pressure ratio (RAP:PCWP)
- Lower RV stroke work index (RVSWI)
The association of lower PAPi with worse clinical outcomes was more pronounced at higher BMI; for example, a 1-standard deviation (SD0 lower PAPi was associated with a 6% higher hazard of mortality at a BMI of 20 kg/m² but was associated with a 23% higher hazard of mortality at a BMI of 40 kg/m².
Similarly, the association of higher RA:PCWP ratio with greater mortality was more pronounced at higher BMI; for example, a 1-SD higher PAPi was associated with a 3% higher hazard of mortality at a BMI of 20 kg/m² but was associated with a 22% higher hazard of mortality at a BMI of 40 kg/m².

Limitations

This was a hospital-based study of ambulatory and hospitalized patients undergoing right heart catheterization for clinical indications and the findings may not be generalizable to other types of patients.
It was an observational study with possible residual confounding, so it cannot show cause and effect.
The code-based diagnoses of heart failure endpoints may have introduced misclassifications.

Disclosures

One of the researchers is supported by NIH grants.
The researchers have no relevant financial disclosures.

This is a summary of a preprint research study, “Obesity Modifies Clinical Outcomes of Right Ventricular Dysfunction,” written by researchers from Boston, Massachusetts, Portland, Oregon, and Durham, North Carolina. Preprints from medRxiv are provided to you by Medscape. This study has not yet been peer reviewed. The full text of the study can be found on medRxiv.

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