A Simple Combined Clinical and Echocardiographic Score Associated with Adverse Long Term Outcomes in Patients with Heart Failure: A Single Center Experience

Research Article

Austin J Cardiovasc Dis Atherosclerosis. 2015; 2(2): 1016.

A Simple Combined Clinical and Echocardiographic Score Associated with Adverse Long Term Outcomes in Patients with Heart Failure: A Single Center Experience

Aggarwal A1, Khoury Abdulla R1, Mehta N2, Goldstein J1,2, Dixon SR1,2, Berman A1,2 and Abbas AE1,2*

1Department of Cardiovascular Medicine, Beaumont Health, Royal Oak, MI, USA

2Oakland University William Beaumont School of Medicine, Royal Oak, MI, USA

*Corresponding author: Amr E Abbas, Department of Cardiovascular Medicine, Beaumont Health, Royal Oak, MI, USA

Received: December 12, 2015; Accepted: December 30, 2015; Published: December 31, 2015

Abstract

Background: In acute decompensated heart failure, it has been shown that the clinical risk factors (CRF) of hypotension and renal dysfunction can be used as an inpatient clinical risk prediction model. However, the long-term predictive value of CRF and the incremental benefit of echocardiographic variables have not been fully investigated.

Methods: We retrospectively identified all patients admitted with acute heart failure during the study period. We examined the clinical, echocardiographic variables and their association with Major Adverse Cardiac Event (MACE) at 18 months, logistic regression models and Kaplan- Meier curves were then derived. A combined echo and clinical score was developed to further risk stratify these patients according to MACE at 18 months.

Results: 120 patients were included. CRFs were associated with MACE at 18 months with C-statistic of 0.65. The echocardiographic indices of both Tricuspid Regurgitation Velocity (TRV) = 3.2 m/s and the ratio of mitral inflow E wave velocity to the mitral annular E’ velocity (E/E’) = 15 improved the C-statistic to 0.73. Adding age, further improved the C-statistic to 0.80 with an earlier onset of MACE in the presence of echocardiographic variables. A simple score (0-4) further stratified the incidence of MACE at 18 months.

Conclusion: In patients with acute heart failure, the strong prognostic value of hypotension and renal dysfunction of in-hospital mortality was not extended to MACE at 18 months. However, the addition of TRV and E/E’ together with age improved the late-outcome prognostic risk score model.

>Keywords: Heart failure; Clinical risk factors; Doppler risk factors

Abbreviations

ASE: American Society of Echocardiography; CRF: Clinical Risk Factors; E/E’: Ratio of Mitral Inflow E Wave Velocity to the Mitral Annular E’ Velocity; MACE: Major Adverse Cardiac Events; LVOT: Left Ventricular Outflow Tract Time Velocity; TRV: Tricuspid Regurgitation Velocity

Introduction

Heart failure is one of the leading causes of morbidity and mortality in the United States. With over one million annual hospital admissions and a one-year mortality of 30%, the annual health care costs exceed 17 billion dollars [1]. Approximately 60% of patients are readmitted to the hospital within six months of discharge [2]. Moreover, readmissions for HF have become a quality standard that is linked to incentive based reimbursement and quality metrics for health systems [1].

Accordingly, stratifying patients based on their risk profile for adverse outcomes may improve disease management, for example by identification of a subset of patients at higher risk for adverse outcomes that may require and benefit from closer monitoring. Several clinical and echocardiographic risk models to better establish long term prognosis have been proposed [2-10].

The large multicenter Acute Decompensated Heart Failure National Registry (ADHERE) registry demonstrated that the combination of the Clinical Risk Factors (CRFs) of systolic blood pressure <115 mmHg, blood urea nitrogen >43 mg/dl, and creatinine > 2.75 mg/dl were associated with in-hospital mortality in patients with acute HF with both reduced and preserved ejection fraction [11]. Furthermore, previously studied echocardiographic parameters (such as ventricular and atrial volumes) may independently identify patients with adverse outcome such as HF exacerbation and cardiac death [3,6]. The Echo Heart Failure Score identified several echo criteria (left ventricular end systolic volume index, mitral deceleration time, and left atrial volume index, pulmonary artery systolic pressure, and the tricuspid annular peak systolic excursion that predicted mortality in systolic heart failure patients at 34 months [3]. However, a simple combined clinical and echocardiographic risk score is not available.

Methods

This study was compliant with the Health Insurance Portability and Accountability Act and the database was conducted under the auspices of the Human Investigation Committee of the Research Institute of William Beaumont Hospital. We retrospectively reviewed the medical records of consecutive patients admitted to Beaumont Health System, with the diagnosis of acute heart failure from January 1st 2011 to December 31st 2011. Diagnosis of heart failure was made by clinical evaluation and confirmed by both B-type natriuretic peptide and chest x-ray findings and noted on the discharge diagnosis. Our exclusion criteria included age >90 years, moderate or severe aortic or mitral valvular disease, technically difficult studies with inadequate Doppler signals, and patients with prosthetic valves.

Clinical characteristics such as age, sex, weight, systolic blood pressure, mean arterial pressure, history of hypertension, coronary artery disease, diabetes, and hyperlipidemia were recorded on the day of admission. Medications such as digoxin, β-blockers, aspirin, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and diuretics including aldosterone antagonists were recorded on the day of admission. Laboratory variables including blood urea nitrogen, creatinine, and sodium level were reported on day of admission. Risk model variables from the ADHERE registry (Systolic Blood pressure <115 mmHg, Creatinine > 2.75 mg/dl, and Blood Urea Nitrogen > 43 mg/dl) were termed traditional Clinical Risk Factors (CRF). Major Adverse Cardiovascular Events (MACE) were defined as death, myocardial infarction, stroke, cardiac arrest, and implantable cardiac defibrillator firing at 18 months.

Two experienced observers independently reviewed transthoracic 2-D Echocardiographic images obtained within the first 24 hours of hospitalization. All echocardiographic data were obtained and all calculations were performed as recommended by the American Society of Echocardiography (ASE) consensus documents [12].

The 2-D echocardiographic parameters include ejection fraction, inferior vena cava diameter and compressibility, and left ventricular end diastolic volume. The Doppler echocardiographic parameters include mitral valve E and A wave velocities, mitral valve deceleration time, tricuspid regurgitation velocity, Left Ventricular Outflow Tract time velocity (LVOT) integral, and E’ velocity. The calculated Doppler echocardiographic parameters include RV systolic pressure, E/A, E/E’, stroke volume, and cardiac output using the heart rate at the time of echocardiography.

After identifying patients who met the inclusion criteria, we divided the patients into two groups depending on whether or not they suffered a MACE. We then performed univariate and multivariate analyses for clinical and echocardiographic parameters between the two groups. Categorical variables were reported as counts and frequencies. They were examined using Pearson’s Chi-square tests where appropriate (expected frequency>5), and otherwise Fisher’s Exact tests were used. Continuous variables were tested for normality. Normally distributed variables were analyzed using twosample t-tests. Non-normally distributed variables were examined using Wilcox on rank tests. All continuous variables were reported as means and standard deviation followed by the median and 25th and 75th percentiles where needed.

We examined several separate logistic regression models to predict MACE at 18 months by including both clinical and echocardiographic variables. We then completed backward elimination logistic regression analysis of MACE at 18 months including all significant predictors of an event from previous analyses. Kaplan-Meier curves were completed to examine MACE at 18 months according to the presence of both, none, or either of TRV=3.2 and E/E’=15. The Jonckheere-Terpstra test for trend was utilized to test for a trend of incremental benefit of combined CRFs and echocardiographic variables that were associated with MACE. SAS® for Windows 9.3 Cary, NC was used for all analyses.

Results

During the period from January 1st, 2011, to December 28th 2011, 259 patients were admitted with the diagnosis of acute heart failure. Of those, 139 patients were excluded based on at least one of the exclusionary criteria; 2 patients were excluded based on age > 90, 115 patients were excluded due to moderate to severe left-sided valvular disease, and 22 patients were excluded due to inadequate Doppler signals, leaving 120 patients who were included in the analysis.

At 18 months, 33/120 (27 %) patients suffered MACE, while 87/120 (73 %) did not.

The baseline demographics between these two groups are illustrated in (Table 1A). The echocardiographic characteristics in the two groups are shown in (Table 1B). Of those patients who experienced MACE, the mean age was higher, the estimated glomerular filtration rate was lower, and a history of coronary artery disease was more frequent compared to those patients who did not have MACE at 18 months (Table 1A). The distribution of major adverse cardiac events is shown in (Table 2). The majority of events were death followed by cardiac arrest and myocardial infarction (Table 2).