Direct comparison of adenosine-versus exercise echo-derived distal left anterior descending artery velocity reserve

Abstract Introduction Distal left anterior descending (LAD) velocity reserve (CVR) estimated by vasodilators has been introduced in stress echocardiography as both diagnostic and prognostic parameter. Exercise echocardiography in the form of supine ergometry (Erg) is currently extensively used and provides an alternative means to evaluate CVR. Aim Aim of the study was to assess the relationship between the CVR estimated by Erg and the respective one by adenosine (Ad) immediately after Erg recovery. Methods Among 73 patients who underwent Erg and were initially screened, 59 (80.8%, age 63±12 years, 45 male, 14 female) with an efficient detection of LAD flow during Erg were studied (19 interrogated for coronary artery disease-CAD, 16 for heart failure with preserved ejection fraction-HFpEF, 7 for asymptomatic aortic stenosis-AS, 17 for mitral regurgitation-MR). Distal LAD velocity was measured at rest and every 2 min during Erg, provided that a clear envelope was feasible. Time elapsed for the detection of peak velocity and the respective achieved heart rate (Peak V-HR) were measured. CVR-Ad was estimated blindly by a different operator 30 minutes after Erg recovery. Absolute (dCVR) and % difference (%dCVR) between CVR-Erg and CVR-Ad were calculated. Results In 62.7% of cases the maximum CVR-Erg was detected earlier than 3 min during Erg. The respective Peak-V-HR was 81±11% of the maximum HR achieved during Erg. CVR-Erg was lower than CVR-Ad (2.17±0.61 vs 2.95±0.60, p=0.0001). The underlying substrate did not affect the difference dCVR (CAD: 0.81±0.70, HFpEF: 0.84±0.72, AS: 0.86±0.60, MR: 0.62±0.65, p=0.76). dCVR and %dCVR were inversely related with the CVR-Erg (r=−0.63, p=0.0001, r=−0.69, p=0.0001 respectively). A greater than 1.7 CVR-Erg had a 100% predictive accuracy for CVR-Ad greater than 2.0. CVR-Ad was predicted by the CFR-Erg using the following linear regression: CVR-Ad = 0.258 x CVR − Erg + 2.290 Conclusion CVR-Erg evaluation is feasible in the majority of patients undergoing Erg for contemporary guidelines indications, even at a relatively low workload, and may be used as a surrogate for CVR-Ad for either diagnostic or prognostic purposes. The observed metric discrepancies may be explained by the different coronary artery/microvasculature dynamics applied by exercise and vasodilators. Funding Acknowledgement Type of funding sources: None. LAD velocity at baselineLAD velocity at peak exercise