Is faster always better?

Background

In the past few years it has been found that primary restoration of the IRA following recent myocardial infarction is the best solution for preserving the left ventricular function.

Objective

To assess the importance and benefit of early primary PCI.

Methods

Our study included 40 patients (35 males, five females, mean age 50.9 years) with first anterior MI. They were divided into two groups. Group A (20 patients) who had the chance of undergoing primary PCI within a mean 5.4 hours of the start of chest pain and a door to balloon time of 1.6 hours, and group B (20 patients) with delayed hospitalization (i.e. >12 hours) and neither received thrombolytic nor primary PCI, but were scheduled as routine PCI with mean 20.7 days. The LV function and dimensions were assessed by serial echocardiographic readings measuring left ventricle end diastolic volume (LVEDV), left ventricle end systolic volume (LVESV), ejection fraction (EF), regional wall motion scoring index (RWMI) at 24 hours of admission and after 3 and 6 months. Results are expressed as the mean ± SD, with P < 0.05 considered significant.

Results

At 3 months, group A showed significant improvement in RWMI (from 1.9 ± 0.3 to 1.27 ± 0.13) with P = 0.032 and there was a nonsignificant increase in the LVEDV value (from 101 ± 17.6 to 109 ± 20.1), and it was found that there was a minimal change in the EF value in group A (59.6 ± 3.9% at baseline to 58.5 ± 0.5%). At 6 months, there was no more improvement in the RWMI in both groups but the delayed group showed a marked increase in LVEDV (from 98.3 ± 22.3 at baseline to 138 ± 32.96 after 6 months; i.e. 38.9% increase in volume versus <20% changes in the primary group [from 101 ± 17.6 at baseline to 115 ± 32.14 at 6 months], and P ≤ 0.05). Whereas the EF% value was nearly preserved in group A (59.6 ± 3.9% at baseline to 59.9 ± 6.81%) there was remarkable deterioration in the EF% value in the delayed group (from 57.1 ± 9.3% at baseline to 51.8 ± 10.8% after 6 months). In spite of early restoration of blood flow in the IRA in group A, and the marked improvement in the RWMI, there were only two patients (10%) who had an increase in the LVEDV >20% of the baseline echo (from 87.5 to 116), with a deterioration in the EF%; they were both diabetic and both hypertensive, with an arrival time to hospital of 7.5 hours and a door to balloon time of 2 hours (i.e. > mean time of group A by 30%).

Conclusion

Our data showed that early and immediate revascularization (primary PCI) is superior to delayed, but a few minutes of microcirculation obstructions can still affect left ventricular function in spite of prompt revascularization.