Left Atrial Distensibility to Predict Prognosis in Consecutive Patients

March 7, 2011 updated by: Kaohsiung Veterans General Hospital.

Studies on Assessment of Left Atrial Distensibility to Predict Late Prognosis in Consecutive Patients Received Echocardiographic Examination

Left ventricular filling pressure (LVFP) has prognostic significance in patients with heart failure. Traditionally, it should be assessed by invasive method, as cardiac catheterization and Swan-Gung catheter. In advance of new techniques and modality, echocardiography provides some useful parameters for assessing LVFP, such myocardial tissue Doppler imaging. Many articles had documented that peak velocity of early-diastolic trans-mitral inflow velocity divided by early-diastolic velocity over mitral annulus correlated closely to LVFP. However, myocardial tissue Doppler only provides the information of regional myocardium, so patients with regional wall motion abnormality, as coronary artery disease, can't be assessed by this method without handicap. In addition, conduction disturbance, like bundle branch block, also influences the result of myocardial tissue Doppler. For resolving those problems, the investigators had designed a new global parameter to assess LVFP. In the investigators prior study, left atrial distensibility correlated logarithmically to LVFP in patients with severe mitral regurgitation and also in patients with acute myocardial infarction. Left atrial distensibility provided a new viewpoint to assess left ventricular diastolic function and to predict prognosis. This time, to extend left atrial distensibility to general population received echocardiographic examination for predicting prognosis is attempted.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Detailed Description

Introduction High left ventricular filling pressure (LVFP) have been associated with volume overload in patients with heart failure and have also been correlated to some extent with more severe symptoms and lower survival rates. In a study of more than 1000 patients hospitalized with acute decompensated heart failure, those with persistently elevated LVFP more than 18 mmHg had increased 1-year mortality compared with those with LVFP less than 16 mmHg. Investigators have also demonstrated that acute reduction of LVFP with vasodilator therapy can improve cardiac function and reduce mortality risk, suggesting that LVFP is an appropriate marker of cardiac risk and functional improvement. However, LVFP measurement involves invasive catheterization, limiting its clinical use especially in the outpatient setting. In advance of new techniques and modality, echocardiography provides some useful parameters to assess LVFP, such myocardial tissue Doppler imaging. Many articles had documented that peak velocity of early-diastolic trans-mitral inflow velocity divided by early-diastolic velocity over mitral annulus was closed correlated with LVFP. However, myocardial tissue Doppler only provides the information of regional myocardium, so patients with regional wall motion abnormality, such as coronary artery disease, can't be assessed by this method without handicap. In addition, conduction disturbance, like bundle branch block, also influences the result of myocardial tissue Doppler. For resolving those problems, we will design a new global parameter to assess LVFP. In prior study, we disclosed the logarithmic relationship between LVFP and left atrial distensibility in acute myocardial infarction patient received primary coronary intervention. This time, to extend our conclusion to general population received echocardiographic examination is attempted. Additionally, we infer that left atrial distensibility which indicates LVFP would influence long-term prognosis, including the event rate of cardiovascular event, stroke and death.

Purpose Left atrial size, particularly left atrial volume, has been recognized as a marker of left ventricular diastolic dysfunction. Contrary to flow and tissue Doppler parameters, left atrial volume is independent of acute volume load and therefore may provide a more accurate assessment of acute and chronic left ventricular dysfunction. In addition, the measurement of left atrial volume is lack of some handicaps of tissue Doppler, including regional myocardial dysfunction in coronary artery disease and bundle branch block. In recent studies, end-systolic left atrial volume (maximal left atrial volume) was useful to predict the risk of atrial fibrillation after cardiac surgery. The short-term and long-term prognosis of acute myocardial infarction was also associated with left atrial volume. In patients with mitral regurgitation, it could be used to reliably estimate the regurgitant volume. Despite end-systolic left atrial volume provides prognostic significance in many disease entities, left atrium is filling and empty in dynamic cyclic motion, so we speculate that left atrial distensibility, defined as the percentage change of left atrial volume between end-systolic and end-diastolic phase, has more prognostic power to represent LVFP and to predict the prognosis. Based on the phenomenon of that higher LVFP, which will conduct to and stretch left atrium in diastolic phase, induces left atrial distension and makes the reduction of distensibility between end-systolic and end-diastolic phases, we had proved the logarithmic relationship between left atrial distensibility and LVFP.

Materials and Methods

Subjects:

2000 consecutive patients received echocardiographic examinations will be enrolled. The exclusion criteria are including (1) patients with prosthetic mitral valves or mitral stenosis, (2) rhythm other than sinus rhythm, (3) age more than 18 years-old, (4) inadequate image quality, (5) lack of informed consent.

Traditional echocardiographic measurement and myocardial tissue Doppler:

All studies are performed by experienced sonographers and reviewed by staff cardiologists with advanced training in echocardiography. Left ventricular function is assessed by Simpson's method. Mitral regurgitation is graded with color flow imaging. Mitral inflow is assessed with pulsed wave Doppler echocardiography form the apical 4-chamber view. The Doppler bean is aligned parallel to the direction of flow, and a 1- to 2-mm sample volume is placed between the tips of mitral leaflets during diastole. From the mitral inflow profile, the E- and A-wave velocity, E-deceleration time, and E/A velocity ration are measured. Pulmonary venous flow is recorded with pulsed-wave Doppler with a sample volume placed 1 cm into the right upper pulmonary vein. The flow velocities are recorded, and the ratio of systolic to diastolic forward flow (S/D ratio) is calculated. Doppler tissue imaging of mitral annulus over septal, lateral and inferior borders is also obtained from apical views. Diastolic filling is categorized as normal (grade 0), impaired relaxation (grade 1), pseudonormalization (grade 2), and restrictive (grade 3) by a combination of transmitral and pulmonary flow patterns as validated previously.

Left atrial volume measurement:

Left atrial volume is assessed by the biplane area-length method from apical 4- and 2-chamber views. The volumes are measured at end-systolic (just before mitral valve opening or the largest dimension), pre-atrial contraction (just before P wave), and end-diastolic (the smallest dimension or the onset of QRS complex), using the highest frame rate. The left atrial outlines at those three phases retrace off-line for three consecutive beats, then average. The recesses of the pulmonary veins and the left atrial appendage are excluded. The length of left atrium is that of the perpendicular line measured from the middle of the plane of the mitral annulus to the superior aspect of the left atrium. The left atrial volume is calculated as: 0.85 x 4-chamber area x 2-chamber area ÷ the shorter of the two lengths. The volume is indexed for body surface area. Left atrial distensibility is defined as: (end-systole left atrial volume - end-diastole left atrial volume) ÷ end-systole left atrial volume. Left atrial ejection fraction is calculated as: (pre-atrial contraction volume - end-diastole left atrial volume) ÷ pre-atrial contraction volume.

Follow-up:

Clinical outcomes are determined 1-year after indexed examination. Follow-up included assessment for the occurrence of sudden death, heart failure with hospitalization, atrial fibrillation, stroke, and death (both cardiac and non-cardiac) per 3 months by telephone interview.

Interobserver variability:

In all cases, atrial volume is measured by two observers independently. Interobserver variability is calculated as the difference between the values obtained by the tow observers divided by the mean.

Statistical analysis:

SPSS software is used for statistical analysis. All continuous variables are presented as mean ± standard deviation. Comparison of clinical and echocardiographic characteristics is performed by chi-square analysis for categorical variables and by Student t test for echocardiography and other continuous variables. A p value < 0.05 is considered significant. Patients will be subdivided to four quartiles according to left atrial distensibility. Unadjusted survival curves are produced using the Kaplan-Meier method. The log-rank test is used to compare survival curves. Adjusted survival curves are constructed using variables entered into the Cox model set to their mean values in the total population. The hazard ratio of low left atrial distensibility will be assessed by comparing quartile to quartile.

Study Type

Observational

Enrollment (Anticipated)

2000

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Taiwan
      • Kaohsiung, Taiwan, 886
        • Recruiting
        • Kaohsiung Veterans General Hospital
        • Contact:
        • Principal Investigator:
          • Jong-Khing Huang, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Consecutive patients received echocardiographic examinations

Description

Inclusion Criteria:

  • consecutive patients received echocardiographic examination are willing to participate in this study.

Exclusion Criteria:

  • (1) patients with prosthetic mitral valves, or mitral stenosis
  • (2) rhythm other than sinus rhythm
  • (3) age less than 18 years-old
  • (4) inadequate image quality
  • (5) lack of informed consent

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Consecutive patients received echocardiographic examinations
Consecutive patients received echocardiography are willing to participate in this study.
Other: Echocardiography, including the measurements of left atrial (LA) distensibility
The LA volumes were measured at three points: 1) immediately before the mitral valve opening (maximal LV volume or Volmax); 2) at onset of the P-wave on electrocardiography (pre-atrial contraction volume or Volp); and 3) at mitral valve closure (minimal LV volume or Volmin). The LA distensibility was calculated as (Volmax - Volmin)x 100% / Volmin. The LA ejection fraction was calculated as (Volp - Volmin)x 100% / Volp. In all patients, LA volumes were indexed to body surface area (BSA).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
All cause mortality
Time Frame: 2 years
All cause mortality and heart failure with re-hospitalization were defined as hard cardiovascular event.
2 years
Heart failure with hospitalization
Time Frame: 2 years
Heart failure with re-hospitalization is documented by at least one of the following: worse exercise tolerance and respiratory distress with NYHA class III or IV symptoms, presence of pulmonary rales, or chest radiography showing pulmonary congestion, which needs an augmented decongestive regimen with oral or intravenous medications during an in-hospital stay.
2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Atrial fibrillation
Time Frame: 2 years
Enrolled patients with intermittent tachycardia will receive Holter's EKG. Any events of atrial fibrillation documented by EKG or Holter, either paroxysmal or persistent, are accounted.
2 years
Stroke
Time Frame: 2 years
Stroke is defined as a sudden onset of focal neurological deficit more than 24 hours and confirmed by brain computed tomography or magnetic resonance imaging. Trans-esophageal echocardiography is suggested to clarify whether cardiogenic or not for all patients with stroke.
2 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Kaohsiung Veterans General Hospital.

Investigators

  • Principal Investigator: Shih-Hung Hsiao, MD, Cardiovascular Center, Department of Internal Medicine, Kaohsiung Veterans General Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2009

Primary Completion (ANTICIPATED)

July 1, 2011

Study Completion (ANTICIPATED)

July 1, 2012

Study Registration Dates

First Submitted

July 23, 2010

First Submitted That Met QC Criteria

July 27, 2010

First Posted (ESTIMATE)

July 28, 2010

Study Record Updates

Last Update Posted (ESTIMATE)

March 8, 2011

Last Update Submitted That Met QC Criteria

March 7, 2011

Last Verified

July 1, 2009

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • VGHKS99-015

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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