Author + information
- Manish Jain,
- Shelly Rahman Haley and
- Aigul Baltabaeva
Background: Stress Echocardiography (SE) is an established functional test in detection of coronary artery disease (CAD) with well-known advantages and disadvantages of exercise and pharmacological stimulation. We have therefore combined inotropic effect of Dobutamine with physiologic effect of supine bike exercise into the new Hybrid Protocol (HP) and compared the results with conventional protocols (CP) to test non-inferiority.
Methods: The HP involves exercise on supine bike at 3 minute increments of 25W workload up to the target heart rate (THR) with an initial low dose Dobutamine infusion up to 10 mcg/kg/min. The number of views has been increased to acquire colour and spectral Doppler to assess left ventricular (LV) filling pressures, dynamic LV gradient and systolic pulmonary artery pressure. 166 consecutive patients referred for SE underwent the test with HP (Gr 1) and results were compared to SE with Dobutamine in 105 patients (Gr 2). Test was considered positive for CAD if more than 2 LV segments had abnormal response at peak stress.
Results: There was no difference in the duration of the test in both groups. In Gr2 86% of pts required intravenous Atropine and/or isometric exercise to achieve THR or counteract vaso-vagal response compared to 4% in Gr 1 (P<0.0001). Larger proportion in Gr1 achieved 90% THR (49% vs 29% in Gr2, P <0.02). There was slight improvement in test specificity with HP when checked on angiography (86% vs 78% in Gr2, P<0.02). Most importantly use of HP improved significantly test sensitivity (84% vs 45% in Gr2, P< 0.0005). The extended spectrum of images in HP gave an additional advantage in subgroup of patients with dyspnoea in Gr1 (53 patients) where in 28 patients we were able to explain symptoms: 53% were found to have ischaemia, 21% developed significant pulmonary hypertension and 11% had symptomatic dynamic LV cavity gradient. No such benefit from test was derived in Gr2.
Conclusions: Our data shows non-inferiority of HP to CP in diagnosing CAD. Patients in Gr 1 achieved higher peak HR and had less complications as well as significant improvement of test specificity and sensitivity. There was additional diagnostic benefit in subgroup of patients with dyspnoea.
Poster Hall, Hall C
Saturday, March 18, 2017, 3:45 p.m.-4:30 p.m.
Session Title: New Technologies in Echocardiography
Abstract Category: 28. Non Invasive Imaging: Echo
Presentation Number: 1245-218
- 2017 American College of Cardiology Foundation