# Clinical determinants of agreement and discordance between stress SPECT and invasive coronary angiography

## TL;DR

This study explores why stress SPECT and invasive coronary angiography agree or disagree in diagnosing heart disease, and how clinical factors can improve risk assessment.

## Contribution

The study identifies clinical factors influencing agreement between stress SPECT and ICA and proposes a predictive model for better risk stratification.

## Key findings

- 68.2% of patients showed agreement between stress SPECT and ICA results.
- Clinical factors like renal failure and diabetes were linked to agreement, while female sex and higher BMI were linked to discordance.
- A multivariable model combining SPECT and clinical variables improved diagnostic discrimination (AUC 0.72 vs. 0.54).

## Abstract

Stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging offers a non-invasive alternative for invasive coronary angiography (ICA) in diagnosing coronary artery disease (CAD), however often yields inconclusive results. This study aimed to characterize patterns of agreement and discordance between stress SPECT and ICA, and to evaluate potential risk stratification.

We retrospectively analyzed 915 patients with suspected CAD who underwent stress SPECT followed by ICA within three months (enrollment: 2019–2020). Clinical, demographic, and imaging data were extracted from medical records. Variables associated with diagnostic agreement were identified using univariate logistic regression. A predictive model combining SPECT results with clinical variables was developed using backward stepwise logistic regression and evaluated by AUC-ROC.

Diagnostic agreement between stress SPECT and ICA was observed in 624 patients (68.2%), while 291 patients (31.8%) demonstrated discordant results. Agreement was associated with use of nitrates (OR 3.18, 95% CI 1.31–7.73), antiplatelet therapy (OR 2.57, 95% CI 1.86–3.56), renal failure (OR 2.34, 95% CI 1.43–3.84), and type II diabetes mellitus (OR 1.78, 95% CI 1.28–2.48), whereas female sex (OR 0.50, 95% CI 0.34–0.73), smoking (OR 0.72, 95% CI 0.50–1.03), and higher body mass index (BMI; OR 0.95 per kg/m², 95% CI 0.92–0.99) were associated with disagreement. The final multivariable model included stress SPECT results, sex, BMI, smoking status, serum creatinine, renal failure, type II diabetes mellitus, and use of antiplatelets and nitrates and demonstrated improved discrimination compared with SPECT alone (AUC 0.72 vs. 0.54, p < 0.001).

In this exploratory study, clinical factors were associated with an agreement between stress SPECT and ICA. Incorporating clinical context alongside SPECT findings may help inform risk stratification.