The diagnostic value of left-anterior-descending artery velocity assessed by transthoracic Doppler echocardiography for microvascular dysfunction in stenotic left-anterior-descending artery

Abstract

Abstract Background Index of microcirculatory resistance (IMR) has been used as a clinical measure of microvascular function. Transthoracic Doppler echocardiography (TDE) can provide information on the functional status of coronary artery circulation. This study aims to assess the diagnostic value of left-anterior-descending artery (LAD) flow velocity by TDE for microvascular dysfunction. Methods Consecutive patients who were scheduled for elective percutaneous coronary intervention (PCI) for LAD lesions were prospectively enrolled in the single tertiary-care center between April 2020 and July 2021. Pre-PCI LAD diastolic peak velocity (DPV) by TDE at rest and hyperemia were measured. By invasive coronary angiography, quantitative coronary angiography and invasive wire-based physiological indices including fractional flow reserve (FFR) and index of microcirculatory resistance (IMR) were measured. Results A total of 104 patients were studied. Median FFR and IMR values were 0.70 (0.60–0.74) and 20.68 (14.92–31.69), respectively. No significant relationship was observed between FFR and IMR. The prevalence of microvascular dysfunction defined as IMR≥25 was 39.4%. Basal DPV was 25 (20–33) cm/sec, and hyperemic DPV was 51 (41–67) cm/sec. In lesions with IMR≥25, reference diameter (RD) was significantly greater [2.63 (2.22–3.19) mm vs 2.39 (2.09–2.66) mm, p=0.019], basal DPV was lower [26 (18–29) cm/sec vs 29 (22–37) cm/sec, p=0.022)] and hyperemic DPV was lower [49 (19–54) cm/sec vs 56 (42–70) cm/sec, p=0.023] compared to lesions with IMR<25. ROC analysis showed basal DPV and RD are significant predictors of IMR≥25 [basal DPV: AUC 0.633 (0.525–0.742), best cutoff 29cm/sec RD: AUC 0.636 (0.523–0.750), best cutoff 2.84mm]. Multivariable logistic regression analysis showed basal DPV<29cm/sec and RD>2.84mm are independent predictors for IMR≥25 [Odds ratio: 3.08 (1.22–7.78), p=0.017; odds ratio 4.40 (1.55–12.50), p=0.005]. Conclusion Basal DPV by non-invasive pre-PCI TDE and reference diameter can predict lesions with coexisting microvascular dysfunction in LAD territory with functionally significant lesions without the need of vasodilator-induced hyperemia and a wire-based invasive physiological measurement. Funding Acknowledgement Type of funding sources: None.