Long-term effects of intracoronary bone marrow cell transfer on diastolic function in patients after acute myocardial infarction: 5-year results from the randomized-controlled BOOST trial-an echocardiographic study

We have recently observed that intracoronary autologous bone marrow cell (BMC)-transfer improves parameters of diastolic function in patients after acute myocardial infarction at 6 and 18 months. There is no clinical study addressing the long-term effect of BMC transfer on diastolic function. Therefore, we conducted a 5-year follow-up of the BOOST trial to evaluate a sustained benefit on echocardiographic parameters on diastolic function. After successful primary percutaneous coronary intervention (PCI) for acute ST-elevation MI, patients were randomized to a control (n = 28) or BMC transfer group (n = 28). Echocardiography was performed at 4.5 +/- 1.5 days after PCI, at 6, 18, and 60 months. Diastolic function was determined by measuring transmitral flow velocities (E/A ratio), diastolic myocardial velocities (E(a)/A(a) ratio), isovolumic relaxation time (IVRT), and deceleration time (DT). All analyses were performed in a blinded fashion. There was an overall treatment effect of BMC transfer on E/A (0.25 +/- 0.10; 95% CI 0.05-0.44; P = 0.01). E/A ratio was significantly lower at 6 (Control 0.90 +/- 0.07; BMC 1.23 +/- 0.14; P = 0.03) and 18 months (Control 0.87 +/- 0.04; BMC 1.13 +/- 0.09; P = 0.01) in the control group, whereas E/A ratio was not different at 60 months between both groups (Control 0.90 +/- 0.06; BMC 1.05 +/- 0.07; P = 0.12). We found no overall effect of BMC transfer on E(a)/A(a) ratio (0.21 +/- 0.14; 95% CI -0.03 to 0.46; P = 0.09), DT (-12 +/- 11 ms; 95% CI -21 to 28; P = 0.75), IVRT -6 +/- 7 ms; 95% CI -9 to 19; P = 0.43), and E/E(a) ratio (0.58 +/- 0.88; 95% CI -1.18 to 2.34; P = 0.51). Intracoronary autologous BMC transfer provides an overall treatment effect on echocardiographic parameters of diastolic function in patients after AMI. However, this effect is basically related to an early improvement of parameters of diastolic function without a sustained effect on long-term follow-up.