1. Biomarkers that “guide” therapy
Troponin
Hemoglobin
Hba1c
LDL
Urea/creatinine
ECG
Ejection fraction
ACS Anemia Diabetes CV prevention HD, ACE inhibitor Chest pain Heart failure

2. Biomarker axes

3. How we should feel about biomarkers
Measurement (lab)
Precision:
closeness of two or more measurements to each other
Accuracy:
closeness of a measured value to a standard or known value
Biologic variation understood
Methods (evaluation)
Statistics clear and robust
Varying across and within patient groups
Mechanism
Represent pathophysiologic process (static or dynamic)
Management
Added value
Inform decision on diagnosis or treatment
Accuracy refers to the closeness of a measured value to a standard or known value. For example, if in lab you obtain a weight measurement of 3.2 kg for a given substance, but the actual or known weight is 10 kg, then your measurement is not accurate. In this case, your measurement is not close to the known value.
Precision refers to the closeness of two or more measurements to each other. Using the example above, if you weigh a given substance five times, and get 3.2 kg each time, then your measurement is very precise. Precision is independent of accuracy. You can be very precise but inaccurate, as described above. You can also be accurate but imprecise.

4. Paris Criteria
RCT
Ahmed, JACC-HF 2014

5. Canadian Cardiovascular HF Guidelines
We suggest, in ambulatory patients with HF due to systolic dysfunction, measurement of BNP or NT-proBNP to guide management should be considered to decrease HF-related hospitalizations and potentially reduce mortality. The benefit is uncertain in individuals older than 75 years of age (Weak Recommendation, Moderate-Quality Evidence)
Moe et al, CJC 2015.

6. Multi-marker panels
Added value of looking across multiple pathophysiologic axes: same time
Complementary for prognosis
E.g. troponin + BNP + mr-proANP
Does this aid diagnosis?
Does this aid management?

7. GUIDE-IT Study Design
Multicenter, prospective, randomized, parallel control group clinical trial
NIH sponsored (PI: Michael Felker, DCRI)
1100 subjects
12-24 months of follow-up

8. GUIDE-IT Study Design Randomized 1:1 to either: Biomarker Guided Arm:
Treatment Titrated to Achieve Target NT-proBNP < 1000 pg/mL OR
Usual Care:
Treatment titrated based on guidelines