critical appraisal
Download
Skip this Video
Download Presentation
Critical Appraisal

Loading in 2 Seconds...

play fullscreen
1 / 36

Critical Appraisal - PowerPoint PPT Presentation


  • 539 Views
  • Uploaded on

Critical Appraisal. DR Joshna Rajbaran. CARDIAC TROPONIN and OUTCOME in ACUTE HEART FAILURE. NEJM 358;20 MAY 15,2008. THE AIM:. To describe the association between elevated cardiac troponin levels and adverse events in hospitalized patients with ACUTE DECOMPENSATED HEART FAILURE. WHY??.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Critical Appraisal' - thi


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
critical appraisal

Critical Appraisal

DR Joshna Rajbaran

the aim
THE AIM:
  • To describe the association between elevated cardiac troponin levels and adverse events in hospitalized patients with ACUTE DECOMPENSATED HEART FAILURE
slide4
WHY??
  • Because an objective risk-stratification process for the evaluation of acute decompensated heart failure is lacking.
slide5
The value of measuring serum cardiac troponin when a patient presents with acute decompensated heart failure remains uncertain.
nb troponins
NB: Troponins

Trop T & Trop I are regulatory proteins with a very high specificity for cardiac injury . They are released early ( 2-4 hrs) & can persist for up to 7 days.

Troponin testing is primarily used as a tool in diagnosing myocardial infarctions.

Elevated levels suggest myocardial or some form of cardiac damage.

Insignificant if used in the absence of S&S of cardiac disease!!

the key differences
THE KEY DIFFERENCES
  • LARGE STUDY
  • SHORT TERM OUTCOMES
  • IN HOSPITALIZED PATIENTS WITH ACUTE DECOMPENSATED HEART FAILURE.
method
METHOD
  • Registry data:
    • ADHERE( Acute Decompensated Heart Failure National Registry)
    • Observational registry
    • 274 hospitals
    • TIME FRAME :October 2001 January 2004
slide9
Inclusion criteria:

Hospitalization & documentation of the measurement of trop I or trop T at “INITIAL” evaluation

slide10

Exclusion criteria:

serum creatinine level>2.0mg/dl

or 176.8umol/l

  • Ischemic heart failure defined as cause if :

hx coronary artery disease OR

hx myocardial infarction

Not as exclusion criteria!!!

method11
METHOD
  • Troponin measurement:
  • Trop T & trop I were interchangeable levels considered positive, with cut-off based on expert consensus!!
  • Trop T≥0.1µg/l & Trop I ≥1.0µg/l
method12
Method
  • Statistical analysis:
  • Primary out-come all causes
  • Secondary out-come differences in medical mx / procedures / length of stay between +ve & -ve cohorts
  • All outcomes were specified before the data were examined
slide13
Statistical analysis ( cont)
  • Associations between therapy & mortality
  • Controls used in this regard
  • Mortality was adjusted for relevant prognostic factors
slide14
Logistic regression adjusted for:

age / blood urea nitrogen / SBP /

DBP / serum creatinine / serum sodium / HR /dyspnea at rest

  • 1.2% records excluded due to missing values
slide15
SAS software
  • Study designed by all authors
  • ADHERE statisticians
method16
METHOD
  • Source
  • Time period
  • Inclusion criteria
  • Exclusion criteria
  • IHD/Race / Gender
  • troponin measurements justified
  • Statistical analysis explained
  • Tools and teams stated
results
RESULTS
  • Troponin levels & characterists of the patients
slide18
105,388 84,872 ( 80.5% )

Hospitalized Trop tested

Cr < 2mg/dl

67,924

Positive Negative

4240 (6,2%) 63,684

slide20

Troponin- positive patients on admission:

  • Lower SBP
  • Lower EF
  • Less likely AF
  • Summary of characteristics given +ve vs –ve Trop
  • No comparison made for the two proteins as only 2% had both tested!!
revision of terminology
REVISION OF TERMINOLOGY

Odds ratio :provides a more useful way of presenting diagnostic data & can be applied to individual patients in a way that specificity & sensitivity cannot . It is a number btw 0 to infinity IF > 1 indicates that the information increases the likelihood of the suspected diagnoses. IF <1 it decreases the likelihood of the suspected diagnoses!!

slide22

SPECIFICITY: the proportion of patients WITHOUT the disease who are correctly identified by the test.

SENSITIVITY: the proportion of patients WITH the disease who are correctly identified by the test.

results23
RESULTS
  • In-hospital mortality
  • Trop Positive (8.0%) > Trop Negative (2.7%) patients.......... (P<0.001)
  • Actuarial analysis
  • Trop as a continuous variable
  • Adjusted odds ratio for death (P<0.001)
slide24

IHF was not a useful discriminator of Troponin status, nor was it predictive of mortality.

  • IHF Trop +ve 53% Trop –ve 52%
  • Trop +ve mortality 8,4% IHF

7,4% non-IHF

  • Trop –ve mortality 2,8% IHF

2,6% non-IHF

results25
RESULTS
  • Treatment , Troponin status & Mortality
  • Diuretics
  • +ve more likely to receive: nitroglycerine , inotropes & vasodilators
  • Resource utilization and mortality
  • No interaction between treatment & Troponin status with respect to mortality
results26
RESULTS
  • Sample size large but justified
  • Basic data adequately described
  • Variables taken into account
  • Missing data accounted for
  • Numbers add up
  • High risk cohort established
  • Statistical significance assessed
main findings and their value
Main findings and their value:

Prognostic value / cost

Early assessment of risk/ triage & management

Add to existing risk-stratification data for predicting the short term risk of death among patients with acute decompensated heart failure... Blood urea>15.4mmol/l

SBP < 115mm Hg

Cr >243.1µmol/l

More aggressive therapeutic approach justified

slide28

Value of findings from Trop negative cohort

Identifying low risk patients/ planning Rx

  • Other studies the impact of early risk stratification has been supported

BASEL TRIAL

EFFECT STUDY

SMALLER STUDIES-98 CONSECUTIVE PTS

-159 PTS

-RITZ-4 STUDY

slide29

Studies correlating Troponin with physiological variables

  • Impact on guidelines :

National-ACS Trop & brain natriuretic peptide or N- terminal pro-brain peptide.

Current for Heart Failure Trop NOT mentioned & brain nitriuretic peptide only if dx uncertain!!!

slide30
Suggested guideline!!!
  • Measurement of Troponin levels in patients who present with heart failure provides independent prognostic information regarding in hospital death & other clinical outcomes & can be useful for risk stratification of such patients!!!!
limitations
LIMITATIONS
  • Retrospective analysis
  • ADHERE large data set : investigator discretion , diagnosis not objectively ascertained , cause of death not consistently recorded
  • Troponin tests
  • Introduction of variability/ bias
  • Measurement only at admission
  • Interaction with other biomarkers
  • Under represented adverse outcomes
critical appraisal32
Critical appraisal

INFORMATIVE STUDY

AIM/METHOD/FINDINGS

SIGNIFICANCE

STRENGTHS & LIMITATIONS WITH SUGGESTIONS OFFERED

I FOUND NO REASON TO QUESTION THE STATISTICAL APPROACH

SUGGESTIONS FOR FUTURE STUDIES

OTHER RELEVANT STUDIES DOCUMENTED

with relevance to sa
With relevance to SA
  • South African statistics :10 473 mortalities per annum d/t Heart Failure vs. US 55,704
  • Further evaluation of other biomarkers vs Trop T required
  • Cost factors need to be examined
  • Ischaemic heart disease is the commonest cause for acute heart failure in America.
slide34

HOWEVER, in Sub- Saharan Africa the causes in Africans are largely ( > 90%) NON-ISCHAEMIC viz.:

HPT / cardiomyopathy / Rheumatic heart disease / chronic lung disease / pericardial disease

  • Coronary artery disease and it’s complications remain uncommon in Africa but the situation is changing!!
slide35

I found the journal article rather transparent in it’s limitations

  • However, there was one limitation that seemed to stand out:

that some patients with both heart failure and ACS may have been included!!!!

  • I think that with urbanization ,varying risk profiles amongst race groups , risk prone behaviour & diet, that the findings are worthy of consideration in our setting.
slide36
Finally , EARLY RISK STRATIFICATION may help identify patients who are likely to receive the greatest benefit from intensive therapy.....that in itself highlights it’s relevance to emergency medicine!!!!
ad