Increased myocardial oxygen consumption rates are associated with maladaptive right ventricular remodeling and decreased event-free survival in heart failure patients

Ali Ahmadi, Jennifer M. Renaud, Steven Promislow, Ian G. Burwash, Girish Dwivedi, Ran Klein, Jason G. E. Zelt, Robert A. deKamp, Rob S. Beanlands, Lisa M. Mielniczuk
University of Ottawa.
Canada

Journal of Nuclear Cardiology
J Nucl Cardiol 2021; 28: 2784-2795
DOI: 10.1007/s12350-020-02144-x

Abstract
Background: Reduced left ventricular (LV) function is associated with increased myocardial oxygen consumption rate (MVO₂) and altered sympathetic activity, the role of which is not well described in right ventricular (RV) dysfunction.
Methods and results: 33 patients with left heart failure were assessed for RV function/size using echocardiography. Positron emission tomography (PET) was used to measure ¹¹C-acetate clearance rate (k_mono), ¹¹C-hydroxyephedrine (¹¹C-HED) standardized uptake value (SUV), and retention rate. RV MVO₂ was estimated from k_mono. ¹¹C-HED SUV and retention indicated sympathetic neuronal function. A composite clinical endpoint was defined as unplanned cardiac hospitalization within 5 years. Patients with (n = 10) or without (n = 23) RV dysfunction were comparable in terms of sex (male: 70.0 vs 69.5%), LV ejection fraction (39.6 ± 9.0 vs 38.6 ± 9.4%), and systemic hypertension (70.0 vs 78.3%). RV dysfunction patients were older (70.9 ± 13.5 vs 59.4 ± 11.5 years; P = .03) and had a higher prevalence of pulmonary hypertension (60.0% vs 13.0%; P = .01). RV dysfunction was associated with increased RV MVO₂ (.106 ± .042 vs .068 ± .031 mL/min/g; P = .02) and decreased ¹¹C-HED SUV and retention (6.05 ± .53 vs 7.40 ± 1.39 g/mL (P < .001) and .08 ± .02 vs .11 ± .03 mL/min/g (P < .001), respectively). Patients with an RV MVO₂ above the median had a shorter event-free survival (hazard ratio = 5.47; P = .01). Patients who died within the 5-year follow-up period showed a trend (not statistically significant) for higher RV MVO₂ (.120 ± .026 vs .074 ± .038 mL/min/g; P = .05).
Conclusions: RV dysfunction is associated with increased oxygen consumption (also characterized by a higher risk for cardiac events) and impaired RV sympathetic function.

Category
Right Heart Dysfunction Associated with Pulmonary Vascular Disease
Diagnostic Testing for Pulmonary Vascular Disease. Non-invasive Testing

Age Focus: Adult Pulmonary Vascular Disease

Fresh or Filed Publication: Filed (PHiled). Greater than 1-2 years since publication

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