Value of hemodynamic gain index in predicting single versus multivessel obstructive coronary artery disease in a high-risk population

Hemodynamic gain index (HGI) is a newly introduced indicator of ischemia and has been associated with increased mortality. Recent data suggest that HGI is a predictor of obstructive coronary artery disease (CAD), but these data remain scarce and require external validation. The aim of this study is to assess the added value of HGI to stress testing in predicting single versus multi-vessel obstructive CAD in patients who had an exercise stress test (GXT) and subsequently referred for invasive coronary angiography (ICA). Heart rate (HR) and systolic blood pressure (SBP) measurements were recorded at rest and peak stress. Duke treadmill score (DTS) and HGI (SBPpeak x HRpeak - SBPrest x HRrest)/ (SBPrest x HRrest) were calculated. All patients had subsequent ICA as a reference test to match for any CAD within 6 months of the non-invasive evaluation. A total of 245 consecutive patients with a GXT were identified between January 2018 and April 2022. Mean age was 66 ± 9 years with 182 (74.3%) male and 72 (29.4%) diabetics. Mean HGI was 1.19 ± 0.58. There were 162 (66.1%) patients who had obstructive CAD on ICA; 65 (26.5%) with single vessel, 86 (35.1%) with ≥ 2 vessels. Patients with obstructive CAD had lower HGI compared to those with normal ICA/non obstructive CAD (0.95 IQR 0.63-1.32 vs 1.21 IQR 0.88-1.61 respectively, P< 0.001). Furthermore, patients with multi-vessel CAD had lower HGI compared to those with single vessel or no vessel disease (0.91 IQR 0.60-1.27 vs 1.13 IQR 0.81-1.50 respectively, P=0.004). A severely blunted HGI with a cutoff value ≤1.27 was found as significantly associated with multi-vessel CAD (OR 2.15, 95% CI 1.18-3.91), with a sensitivity of 90.7% and a negative predictive value of 77.1%. After multivariate adjustment, a HGI ≤1.27 remained significantly associated with multi-vessel CAD (OR 2.00, 95% CI 1.08-3.70). Among patients who underwent concomitant GXT and ICA, HGI ≤1.27 is a strong predictor of multi-vessel obstructive CAD. HGI is a useful and easily accessible clinical tool that may be used to re-stratify high risk coronary anatomy.