Additional prognostic value of heart rate reserve over left ventricular contractile reserve and coronary flow velocity reserve in diabetic patients with negative vasodilator stress echocardiography by regional wall motion criteria

Aims: In diabetic patients, a blunted left ventricular contractile reserve (LVCR) and/or a reduced coronary flow velocity reserve (CFVR) identify patients at higher risk in spite of stress echocardiography (SE) negative for ischaemia. Cardiac autonomic dysfunction contributes to risk profile independently of inducible ischaemia and can be assessed with heart rate reserve (HRR). We sought to assess the added prognostic value of HRR to LVCR and CFVR in diabetic patients with non-ischaemic SE.

Methods and results: Six-hundred and thirty-six diabetic patients (age 68 ± 9 years, 396 men, ejection fraction 58 ± 10%) with sinus rhythm on resting electrocardiogram underwent dipyridamole SE in a two-centre prospective study with assessment of wall motion, force-based LVCR (stress/rest ratio, normal value > 1.1), CFVR of the left anterior descending coronary artery (stress/rest ratio, normal value >2.0), and HRR (stress/rest ratio, normal value >1.22). All-cause death was the only considered endpoint. During a median follow-up of 39 months, 94 (15%) patients died. Independent predictors of death were abnormal CFVR [hazard ratio (HR) 1.59, 95% confidence interval (CI) 1.0-2.52, P = 0.05], reduced LVCR (HR 1.76, 95% CI 1.15-2.69, P = 0.009), and blunted HRR (HR 1.92, 95% CI 1.24-2.96, P = 0.003). Eight-year death rate was 9% for patients with triple negativity (n = 252; 40%), 18% for those with single positivity (n = 216; 34%), 36% with double positivity (n = 124; 19%), and 64% for triple positivity (n = 44; 7%) (P < 0.0001).

Conclusion: Diabetic patients with dipyridamole SE negative for ischaemia still may have a significant risk in presence of an abnormal LVCR and/or CFVR and/or HRR, which assess the underlying myocardial, microvascular, and cardiac autonomic dysfunction.

Clinical trials: Gov Identifier NCT 030.49995.