Exercise Performance During the First Two Years After Left Ventricular Assist Device Implantation.

Exercise performance of patients with left ventricular assist devices (LVADs) improves after postimplant cardiac rehabilitation (CR). Few studies assess the effectiveness of a CR and its long-term effect of exercise performance. For this purpose, we retrospectively analyzed data from LVAD patients, who underwent a stationary CR twice after pump implantation. Data from exercise training and cardiopulmonary exercise tests (CPETs) were analyzed. Fifteen patients (age: 57 ± 10 years, male 87%) were admitted to the rehabilitation clinic twice 39 ± 18 and 547 ± 197 days after LVAD implantation. An improvement from the beginning to the end of the second CR was observed in bicycle ergometer training (14.0 ± 8.8 vs. 35.7 ± 14.7 W; p < 0.001), in muscular strength (e.g., leg press: 41 ± 10 vs. 53 ± 14 kg; p < 0.001), and in 6 minute walk distance (421 ± 126 m vs. 480 ± 133 m; p = 0.040). Between the first and the second CR, improvement in all the training modules was observed as well as an increase in CPETs peak workload (56 ± 24 vs. 83 ± 26 W; p < 0.001) but not in peak oxygen consumption (12.3 ± 3.2 vs. 12.2 ± 4.0 ml/min/kg; p = 0.906). Thus, over long implant periods, patients showed improvement of their exercise performance in the submaximal load range, but no change in the aerobic capacity was observed.

The Antiplatelet Effect of Clopidogrel Decreases With Patient Age.

Recent data suggest that clopidogrel-mediated platelet inhibition is age dependent. However, so far the effect of age on adenosine diphosphate (ADP)-inducible platelet reactivity has only been investigated by test systems measuring surrogate markers of platelet aggregation. We therefore sought to study the impact of age on platelet inhibition by clopidogrel by whole-blood flow cytometry. Platelet surface P-selectin expression, activated glycoprotein (GP) IIb/IIIa, and monocyte-platelet aggregate (MPA) formation were determined by flow cytometry in 302 patients with dual antiplatelet therapy after successful angioplasty and stenting. Patient age was independently associated with ADP-inducible P-selectin expression, GPIIb/IIIa, and MPA formation (all P < .05). Moreover, platelet surface expressions of P-selectin and activated GPIIb/IIIa were significantly higher in patients ≥75 years compared with younger patients (both P ≤ .004). Likewise, MPA formation was significantly more pronounced in patients ≥75 years ( P = .02). Finally, high P-selectin and high GPIIb/IIIa were significantly more frequent in patients ≥75 years compared with younger patients (both P < .001). Further, high MPA ADP occurred more frequently in patients ≥75 years compared to younger patients ( P < .05). In conclusion, the antiplatelet effect of clopidogrel decreases with patient age.

Response to antiplatelet therapy and platelet reactivity to thrombin receptor activating peptide-6 in cardiovascular interventions: Differences between peripheral and coronary angioplasty.

BACKGROUND: The long-term prognosis of patients with peripheral arterial disease (PAD) is significantly worse than the prognosis of coronary artery disease (CAD) patients. Detrimental platelet activation could contribute to the increased rate of adverse cardiovascular events in PAD. We therefore investigated whether response to antiplatelet therapy and thrombin inducible platelet activation differ between patients with best medical therapy undergoing angioplasty and stenting for symptomatic PAD (n = 166) or CAD (n = 104). METHODS: Adenosine diphosphate (ADP), arachidonic acid (AA) and thrombin receptor activating peptide (TRAP)-6 inducible platelet reactivity was measured by multiple electrode aggregometry (MEA). Platelet surface expression of P-selectin and activated glycoprotein IIb/IIIa (GPIIb/IIIa) in response to ADP, AA, and TRAP-6, and the formation of monocyte-platelet aggregates (MPA) in response to ADP and TRAP-6 were assessed by flow cytometry. RESULTS: Patients with PAD had significantly higher platelet reactivity in response to ADP and AA by MEA compared to CAD patients. Likewise, the expression of P-selectin and GPIIb/IIIa following stimulation with ADP and AA, and MPA formation in response to ADP were significantly higher in PAD patients than in CAD patients. In response to TRAP-6, patients with PAD showed a significantly increased platelet aggregation by MEA, higher expression of activated GPIIb/IIIa, and more pronounced formation of MPA than CAD patients. CONCLUSION: Following angioplasty and stenting, PAD patients exhibit a significantly diminished response to dual antiplatelet therapy and an increased susceptibility to TRAP-6 inducible platelet activation compared to CAD patients.