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High output cardiac state: evaluating the incidence, plausible etiologies and outcomes
Hilary Bews1, Sangyang Jia2, Yixiu Liu3
1Section of Cardiology, Department of Internal Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.
Insights
High output cardiac state (HOCS) is an under-recognized condition characterized by low systemic vascular resistance. This study found HOCS is not uncommon and linked to significant mortality, necessitating updated heart failure diagnostic criteria.
Area of Science:
- Cardiology
- Hemodynamics
- Critical Care Medicine
Background:
- High output cardiac state (HOCS), defined by a high cardiac index (CI >4 L/min/m²), is often driven by low systemic vascular resistance (SVR).
- Many HOCS patients meet heart failure (HF) criteria, but standard HF therapies may worsen SVR, complicating treatment.
- HOCS remains relatively under-recognized despite its potential impact on patient outcomes.
Purpose of the Study:
- To characterize the clinical profile of patients with HOCS.
- To identify common etiologies, diagnostic findings, and outcomes associated with HOCS.
- To provide insights for improved recognition and management of HOCS.
Main Methods:
- Retrospective review of patients undergoing right heart catheterization (RHC) between 2009 and 2021.
- Inclusion criteria: CI >4 L/min/m² (HOCS) or 3.8-4.0 L/min/m² (pre-HOCS).
- Analysis of medical records for etiologies, investigations, and patient outcomes.
Main Results:
- 177 patients met inclusion criteria (144 HOCS, 33 pre-HOCS).
- Common HOCS etiologies included anemia (36%), obesity (34%), lung disease (32%), and cirrhosis (17%).
- HOCS and pre-HOCS groups showed high hospitalization and mortality rates (25% and 39% respectively).
Conclusions:
- HOCS is a prevalent condition associated with substantial mortality.
- Diagnostic criteria for heart failure should consider evaluating for HOCS.
- Further research is needed to optimize treatment strategies for HOCS.
Introduction:
The high output cardiac state (HOCS) [cardiac index (CI) >4 L/min/m2 ], primarily driven by abnormally low systemic vascular resistance (SVR), is a relatively under-recognized condition. Although, majority of these patients meet criteria for heart failure (HF), their treatment should be aimed at the primary pathology, as the majority of guideline directed HF therapies can reduce SVR further.
Objectives:
To characterize patients with HOCS and provide valuable insight into the condition.
Methods:
Patients investigated by right heart catheterization (RHC) at the St. Boniface Hospital, Winnipeg, Canada between January 2009 and November 2021 were reviewed. Two groups of patients were included: 1) HOCS [CI >4 L/min/m2], and 2) pre-HOCS [CI between 3.8-4.0 L/min/m2]. Their medical records were reviewed to identify plausible etiologies, relevant investigations, and outcomes.
Results:
177/2950 (6 %) patients met criteria for inclusion: 144/177 (81 %) with HOCS [mean age 51 years (range 19 - 82); 67/144 (47 %) female] and 33/177 (19 %) with pre-HOCS [mean age 55 years (range 30 - 83); 6/33 (18 %) female]. The most common plausible etiologies for the HOCS included anemia (36 %), obesity (34 %), cirrhosis (17 %), and lung disease (32 %). Trans-thoracic echocardiography and magnetic resonance imaging findings were non-specific and predominantly described preserved left ventricular ejection fraction, and pulmonary hypertension. The population experienced high rates of hospitalization, and significantly high mortality [36/144 (25 %) of HOCS at a median follow-up of 31.5 months, and 13/33 (39 %) of pre-HOCS at a median follow-up of 17 months].
Conclusions:
HOCS is not an uncommon condition and is associated with high mortality. Current HF guideline should incorporate such evaluation into the diagnostic criteria.
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