P1786 Impact of exercise on platelet activity in patients with significant ischemic mitral regurgitation qualified for cardiosurgery treatment

Abstract

Abstract Purpose Platelet activity is believed to play an important role in patients (pts)after myocardial infarction (MI). This study sought to examine a change in platelet activity after 2D echocardiography semi-supine exercise test (ExE) in pts with at least moderate ischemic mitral regurgitation (IMR) qualified for cardiosurgical treatment - coronary artery bypass grafting alone (CABG) or CABG with mitral reconstruction (CABGmr). Methods We collected venous blood samples from 70 patients (M 41, 66 ± 9 years) with at least moderate IMR, 3-24 weeks after MI. Platelet activity was estimated with the use of rapid, point-of-care platelet analyzer as the time (in seconds) for flowing whole blood to occlude a collagen-epinephrine ring, with shorter closure times, indicating greater activity (CEPI-CT- for assessing the thromboxane A2 –dependent activation pathway). CEPI-CT was evaluated before (CEPI-CT rest) and 20 min after ExE (CEPI-CT ExE). All the patients received 75-100 mg of aspirin daily (without clopidogrel treatment). Effective regurgitation orifice (ERO) was used for quantitative IMR assessment (moderate ≥10-20, severe ≥ 20 mm²). All the pts were referred for CABG (multivessel coronary disease, ejection fraction (EF) 42,6 ± 10,1%, wall motion score index (WMSI) 1.65 ± 0.36). Results We observed a significant decrease in CEPI–CT’s in all analyzed group (rest vs exe: 202 sec vs 124 sec, respectively; p < 0,0001) and in pts with moderate IMR as well as in pts with severe IMR, despite aspirin treatment. The results of the analysis of CEPI-CT and IMR size at rest and after ExE in both groups of pts are shown in Table 1. A negative correlation was found between CEPI-CT ExE and ERO ExE (r=-0,752, p = 0,0042). Conclusions 1. Significant increase in platelet activity after exercise was observed in patients after MI with IMR qualified for cardiosurgical treatment. 2. The increase in platelet activity after exercise is correlated with exercise changes of IMR size. 3. Aspirin may have a limited antithrombotic effect after physical exercise in patients after MI with significant IMR. Table 1. CEPI-CT rest CEPI-CT ExE p ERO rest ERO exe p All 202 124 < 0,0001 17 22 <0,001 Moderate IMR 201 124 0,0001 15 20 < 0,0001 Severe IMR 235,5 123,5 < 0,0001 25 31 < 0,0001