Early post-stress decrease in cardiac performance by impedance cardiography and its relationship to the severity and extent of ischemia by myocardial perfusion imaging

Q: What are the key findings of this study?

Patients with >10% myocardial ischemia had a post-exercise stroke index change of - in those with <=10% ischemia, with any decrease showing 70.0% sensitivity and 73.1% specificity.

Q: What is the clinical evidence from this study?

Study design: Observational. Population: Suspected or known coronary artery disease undergoing exercise stress myocardial perfusion imaging (n=198). Intervention: Myocardial ischemia > 10% on SPECT MPI (evaluated by NICaS impedance cardiography) vs. Myocardial ischemia <= 10% on SPECT MPI. Primary outcome: Percentage change in post-exercise stroke index (SI) from rest to stress (p=0.015).

Q: What does this research mean for the field?

A post-exercise decrease in stroke index measured by impedance cardiography detects significant myocardial ischemia (>10%) with 70.0% sensitivity and 73.1% specificity. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

Ronen Goldkorn; Alexey Naimushin; Eli Rozen; Dov Freimark

doi:10.1186/s12872-020-01639-2

July 31, 2020BMC Cardiovascular DisordersOpen Access

Early post-stress decrease in cardiac performance by impedance cardiography and its relationship to the severity and extent of ischemia by myocardial perfusion imaging

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Key result

Myocardial ischemia >10% linked to ~22-point lower post-exercise stroke index change.

P=0.015
n=198

Why the study?

SPECT myocardial perfusion imaging can miss or underestimate the extent of CAD in certain patients. This study evaluated whether a bio-impedance device detecting early post-stress hemodynamic changes could serve as a marker for significant ischemia.

Key Points

To evaluate whether post-stress hemodynamic changes measured by a non-invasive bio-impedance device correlate with the severity and extent of myocardial ischemia on SPECT myocardial perfusion imaging.
Prospectively enrolled 198 patients referred for clinically indicated myocardial perfusion imaging (mean age 62 years, 26% women, 54% hypertension, 29% diabetes mellitus).
Measured rest and immediate post-exercise hemodynamics using a Non-Invasive Cardiac System (NICaS) bio-impedance device, comparing patients with ≤10% (n=188) versus >10% (n=10) myocardial ischemia.
Patients with ≤10% ischemia exhibited significantly larger post-exercise increases compared with the >10% group in stroke index (19.2% [95% CI, 15.2 to 23.2%] vs. -2.7% [95% CI, -8.2 to 2.7%], p=0.015), stroke work index (29.1% vs. 3.8%, p=0.017), cardiac index (90.5% vs. 43.7%, p=0.040), and cardiac power index (107% vs. 53.5%, p=0.016).
Total peripheral resistance index decreased significantly more in patients with ≤10% ischemia compared to those with >10% ischemia (-38.7% [95% CI, -41.0 to -36.4%] vs. -16.3% [95% CI, -30.7 to -1.8%], p<0.001).
A post-stress decrease in stroke index (change < 0) identified myocardial ischemia >10% with 70.0% sensitivity and 73.1% specificity.

Study Design

Type

Observational (n=198)

Multicenter

No

PICO

P

Population

198 adults (mean age 61.8 years, 26% female) referred for clinically-indicated exercise stress myocardial perfusion imaging, excluding those with unstable angina, decompensated heart failure, or severe aortic stenosis.

E

Exposure / Comparator

Myocardial ischemia > 10% on SPECT MPI (evaluated by NICaS impedance cardiography) vs Myocardial ischemia <= 10% on SPECT MPI

O

Primary Outcome

Percentage change in post-exercise stroke index (SI) from rest to stress, p=0.015

Main Result

Absolute Event Rate: -2.7% vs 19.2%

p-value: p=0.015

Limitations

Beta-blocker therapy was discontinued at least 24 hours prior to testing and no information was available regarding the use of other medications
Findings are applicable only to patients with an intermediate pretest probability for CAD without significant comorbidities
Small number of patients (n=10) with myocardial ischemia > 10%
Reproducibility of measured hemodynamic parameters may be limited by patients' physical fitness and test-day performance
Lack of echocardiographic data to assess valvular comorbidity and validate resting stroke volume
Lack of correlation with true coronary anatomy by coronary angiography

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Implication

Post-exercise stroke index decline may flag significant ischemia; leaves open its diagnostic role pending prospective validation.

Abstract

BACKGROUND: While single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a well-established noninvasive procedure for the evaluation of patients with coronary artery disease (CAD), it is unable to detect the presence of, or underestimates the extent of CAD in certain patients. We aimed to show that a bio-impedance device can detect early post-stress changes in several hemodynamic parameters, thereby serving as a potential marker for the presence of significant ischemia. METHODS: Prospectively enrolled patients, referred to our Medical Center for clinically-indicated MPI, underwent testing using a Non-Invasive Cardiac System (NICaS) before and immediately after exercise. The differences between rest and stress hemodynamic parameters were compared with the severity and extent of myocardial ischemia by MPI. The study included 198 patients; mean age was 62 years, 26% were women, 54% had hypertension, and 29% diabetes mellitus. Of them, 188 patients had ≤10%, and 10 had > 10% of myocardial ischemia. RESULTS: In the first group, there was a significantly greater increase in post-exercise stroke index, stroke work index, cardiac index and cardiac power index (19.2, 29.1, 90.5 and 107%, respectively) compared with the second group (- 2.7, 3.8, 43.7 and 53.5%, respectively), as well as a significantly greater decrease in total peripheral resistance index (- 38.7% compared with - 16.3%), with corresponding p values of 0.015, 0.017, 0.040, 0.016, and < 0.001, respectively. CONCLUSIONS: Our data suggest that immediate post-stress changes in several hemodynamic parameters, detected by the NICaS, can be used as an important adjunct to SPECT MPI for the early detection of myocardial ischemia.

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Cite This Study

Goldkorn et al. (2020) conducted an observational in Suspected or known coronary artery disease undergoing exercise stress myocardial perfusion imaging (n=198). Myocardial ischemia > 10% on SPECT MPI (evaluated by NICaS impedance cardiography) vs. Myocardial ischemia <= 10% on SPECT MPI was evaluated on Percentage change in post-exercise stroke index (SI) from rest to stress (p=0.015). Patients with >10% myocardial ischemia had a post-exercise stroke index change of - in those with <=10% ischemia, with any decrease showing 70.0% sensitivity and 73.1% specificity.

synapsesocial.com/papers/6ade2e764f527491e29bd0d0 https://doi.org/10.1186/s12872-020-01639-2

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Early post-stress decrease in cardiac performance by impedance cardiography and its relationship to the severity and extent of ischemia by myocardial perfusion imaging

Key Points

Study Design

PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Early post-stress decrease in cardiac performance by impedance cardiography and its relationship to the severity and extent of ischemia by myocardial perfusion imaging

Key Points

Study Design

PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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