Stress Echo 2030

ABCDE+ Protocol

Cardiology Rounds Oct 16, 2024 | Atul Jaidka

Objectives

  1. Discuss components of the ABCDE+ Protocol
  2. Discuss evidence for the ABCDE+ Protocol
  3. Practical applications of the ABCDE+ Protocol in the Echo Lab

Background

Traditional Stress Echo

  • Identification of regional wall motion abnormalities to identify obstructive coronary artery disease
    • Qualitatively assessed

 

  • Other prognostic parameters:
    • Exercise duration, BP response, ST-T changes and LV dilation (not reliably reported)

 

  • Functional test: thus does not diagnose non-obstructive atherosclerotic disease that can still cause events

Compared to Alternatives

  • Advantages
    • ​Inexpensive
    • No radiation
    • Portable
    • Exercise and non-exercise
    • Less environmental impact compared to MRI/SPECT

Compared to Alternatives

  • Disadvantages
    • Functional testing thus may not pick up non-obstructive clinical atherosclerosis that can cause future events
      • Compared to Coronary CT
    • WMA are later in the ischemic cascade (not capturing perfusion changes)
      • Compared to myocardial perfusion imaging
    • WMA based protocol less useful in evaluating INOCA (ischemia with no obstructive CAD)

Rest

Post Exercise

LAD Ischemia

Why New Protocol?

  • Change in referral pattern leading to a dropping positivity rate (<10% in some studies)
    • Reduced predictive value

 

  • Traditional stress echo protocol does not capture other areas of vulnerability in a heterogeneous population beyond identifying obstructive CAD
    • ie. lung water, LV contractile reserve, coronary microcirculation and cardiac autonomic dysfunction

 

  • New parameters are able to be implemented in Echo Labs without new technologies/sofware

ABCDE-SE Protocol

ABCDE-SE Protocol

A - Wall motion abnormalities, volumes*

B - B Lines

C - Left ventricular contractile reserve*

D - Coronary flow reserve

E - Heart rate reserve*

 

*do not require additional imaging based on current protocol

ABCDE Stress Echo

Step A: Myocardial Ischemia

  • Assessment: Wall motion score index, 1 (normal) - 4 (dyskinetic) in a 17 segment LV model
  • Positivity: 2 adjacent segments of same vascular territory increment by at least 1 point

Step B: B Lines

  • Assessment: 4 quadrant lung ultrasound for b lines
  • Positivity: 2 or more  
  • Cardiac transducer
  • Perpendicular to ribs
  • 18cm depth
  • 6s clips
  • 3 Intercostal space
  • Mid-Ax, Mid-clavic

Step B: B Lines

Scali MC, et al. (2020) Lung Ultrasound and Pulmonary Congestion During Stress Echocardiography. JACC Cardiovasc Imaging 13:2085-95.

Example Acquisition

Picano E, et al.. Stress lung Ultrasound stress echo2020.2019. Available at https://www.youtube.com/watch?v=BwzgoG15E_A

Scoring Patients

Scali MC, et al. (2020) Lung Ultrasound and Pulmonary Congestion During Stress Echocardiography. JACC Cardiovasc Imaging 13:2085-95.

  • 4 zone protocol
  • Score each zone from 0-10 B-lines and sum 4 zones
  • Report total at rest and stress and interval change
  • Stress B-lines are categorized as:
    • absent (score points 0 to 1), mild (2 to 4), moderate (5 to 9), and severe (=10 points)

Case

  • RFR: dyspnea
  • 58-year-old female
  • PHT 141 ms, MVA 1.6 cm2 (Mod MS)
  • Mild to moderate regurgitation

Wiley BM, et al. (2020) Lung Ultrasound During Stress Echocardiography Aids the Evaluation of Valvular Heart Disease Severity. JACC Cardiovasc Imaging 13:866-72.

Case

Wiley BM, et al. (2020) Lung Ultrasound During Stress Echocardiography Aids the Evaluation of Valvular Heart Disease Severity. JACC Cardiovasc Imaging 13:866-72.

Step C: LVCR

  • Assessment: Left ventricular contractile reserve is calculated as systolic blood pressure/end-systolic volume
  • Positivity: LVCR < 2 for exercise/dobutamine or <1 for vasodilators

Step C: LVCR

  • Lower number is worse (<2 for exercise or dobutamine)
  • Combines two prognostic variables
    • SBP not rising (or decreasing)
    • ESV not decreasing (or increasing)
  • Creates a unitless variable that is not load dependent

Step D: CFVR

  • Assessment: Coronary flow velocity reserve of mid-distal LAD

 

  • Positivity: CFVR < 2 

 

  • Success rate of 88% in obtaining CFVR on LAD (3000/3410)
    • 80% with exercise (bike) and 81% with dobutamine
    •  Acquisition and Interpretation in < 4 minutes

 

  • Assesses both epicardial CAD and coronary microcirculation

 

  • Dopplers obtained and reviewed offline

 

  • *Note: Stress Echo 2030 protocol, pharm SE or if exercise, then given adenosine bolus at end of recovery to assess CFVR

Step D: CFVR

  • Acquisition: modified low parasternal and apical views
  • Studies agree, onerous, but with training it is possible

 

 

Step D: CFVR

  • Acquisition: modified low parasternal and apical views
  • Studies agree, onerous, but with training it is possible

 

 

Mod PSAX

Mod PLAX

Step D: CFVR

Step D: CFVR

  • Angina
  • No WMA
  • CFVR < 2
  • Dx:  chronic microvascular dysfunction

Step E: HRR

  • Assessment: Heart rate reserve =
    •  [(peak HR - rest HR) / (220 - age) - rest HR]
  • Positivity: HRR <1.8 for exercise/dobutamine or <1.22 for vasodilator 

 

  • Previous studies show blunted HRR is a predictor or adverse events in vasodilator stress echo independent of inducible ischemia and beta blocker therapy

Example: Normal

Example: Abnormal

Study

European Heart Journal 2021

Ciampi et al.

Prognostic value of stress echocardiography assessed by the ABCDE protocol

Design

  • Design: prospective, multi-centre, international, effectiveness study
  • Intervention: ABCDE stress echo protocol
  • Patients: known or suspected chronic coronary syndrome
  • Outcomes: All cause death

Inclusion/Exclusion

  • age >18 years
  • referral for known or suspected CAD
  • no severe primary valvular or congenital heart disease, or presence of prognosis-limiting comorbidities, such as advanced cancer, reducing life expectancy to <1 year
  • echocardiography of acceptable quality at rest and during stress

Results

  • Of those with normal SE who underwent coronary angiography, 30% demonstrated obstructive CAD, whereas in those with all five abnormal steps on SE, 95% had significant CAD.

Predictors of Mortality

  • Postive:
    • B-lines
    • Coronary flow velocity reserve
    • Heart rate reserve
    • ABCDE Score 3 or greater
  • Negative:
    • Regional Wall Motion Abnormalities
    • Left ventricular contractile reserve

 

  • The mortality rate was 0.4%/year for a normal SE compared with 2.7%/year when all SE steps were abnormal.

Incremental Benefit

Study Conclusions

  • Higher ABCDE score predicts less benign outcome

 

  • Regional wall motion abnormalities, most used measure, less helpful in predicting prognosis

 

  • Steps B-E are feasibly added to current stress echo protocols

 

  • Shift assessing only coronary stenosis to patient as a whole
    • Other vulnerabilities including coronary microvascular dysfunction and autonomic dysfunction

Study Conclusions

  • Consider targeting treatments towards the identified abnormal steps

 

  • Stress echo low cost/risk/environmental impact and no radiation

 

  • ABCDE protocol can be used with any stress - exercise or pharmacological (ie. in a global pandemic pharm preferred)

Proposed Tailored Therapy

  • Step A identifies inducible ischemia --> BB/CCB/nitrates or possible revasc

 

  • Step B identifies pulmonary congestion --> diuretics

 

  • Step C (LVCR) identifies LV dysfunction --> ACEi

 

  • Isolated Step D identifies microvascular dx --> statin

 

  • Step E abnormalities can be targets by neurohormonal modulation (ie. BB/ACEi/MRA/renal denervation)

 

Treatments potentially titratable to ABCDE risk score

Discussion

Discussion

  • Dedicated training required to implement protocol
    • Specifically coronary flow of LAD is most challenging

 

  • Originally planned 5000 patients and 3 year followup but achieved ~3600 and 21 month followup
    • 2020 was planned last year of study but COVID

 

  • No other end points other than mortality to assess predictive power of protocol steps
    • Ie. B-lines and HF admissions

Discussion

  • Images were not reviewed by core lab
    • Practical for effectiveness study as has real-world applicability

 

  • Parameters were binary, positive or negative, future studies plan to consider mild-mod-severe stratification

 

  • Most patients underwent dipyridamole stress, would be beneficial to compare predictive value of the steps by stress modality (could explain why physiological measures such as LVCR were not predictive)
    • High score 4-5 were mostly in exercise group

Discussion

  • RWMA may not be a strong enough tool to assess for ischemia as significant oxygen supply demand mismatch is needed
    • Future protocols could employ myocardial contrast echocardiography to assess perfusion
    • Low usage of contrast in general in the study

 

  • Functional testing may not pick up non-obstructive lesions which can still lead to to events
    • Critics recommend carotid ultrasound to pick up on clinical atherosclerosis

Where now?

Modified ABCDE?

ABCDE+

ABCDE + F (regurgitant flow) G (LVOT gradients) L (left atrial volume/function) P ( pulmonary and LV pressures) L (RV function)

Stress Echo 2030

ABCDE + F (regurgitant flow) G (LVOT gradients) L (left atrial volume/function) P ( pulmonary and LV pressures) L (RV function)

Stress Echo 2030

  • 1-SE in coronary artery disease (SECAD)
  • 2-SE in diastolic heart failure (SEDIA)
  • 3-SE in hypertrophic cardiomyopathy (SEHCA)
  • 4-SE post-chest radiotherapy and chemotherapy (SERA)
  • 5-Artificial intelligence SE evaluation (AI-SEE)
  • 6-Environmental stress echocardiography and air pollution (ESTER)
  • 7-SE in repaired Tetralogy of Fallot (SETOF)
  • 8-SE in post-COVID-19 (SECOV)
  • 9: Recovery by stress echo of conventionally unfit donor good hearts (RESURGE)
  • 10-SE for mitral ischemic regurgitation (SEMIR)
  • 11-SE in valvular heart disease (SEVA)
  • 12-SE for coronary vasospasm (SESPASM)

Questions?

"The current shift toward using SE protocols with both known and novel parameters is a new frontier. It will be interesting to observe the impact of SE 2020 in shifting practice. There has been a reluctance to “go with the flow” on this side of the Atlantic, but perhaps this will change with clear demonstration of feasibility and incremental value of a multiparametric SE approach, especially in women, who could benefit greatly from a noninvasive, nonionizing assessment of myocardial microvascular integrity."

-Sharon L. Mulvagh (Editorial Comment)

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