Importance of ischaemic time as a predictor of LV systolic function in Indians.

Objective: Sucessful reperfusion therapy in AMI improves LV systolic function. Success in thrombolytic therapy is directly related to the ischaemic time. Our aim in the present study was to observe the importance of ischaemic time as a predictor of left ventricular systolic function in patients undergoing PPCI. In addition, the contribution of presentation delay in determining the ischaemic time in the Indian scenario was also observed.

Materials & Methods: The present pilot study was carried out on 48 Indian patients (Male-40) of STEMI (Killip class I & II) undergoing primary PCI in last 2 yrs. Suggestive chest pain, ECG evidence of STEMI coming within 12 hrs were the inclusion criteria. Patients coming after 12 hours without ongoing chest pain, Killip class III & IV, the patients who were thrombolysed outside and the patients with prior PCland/or CABG were excluded from the study. Cardiac echodoppler study was done in every patient during followup at one month.Every patient received pre and peri procedural abciximab infusion and thrombosuction was done in all before deployment of BMS during the transfemoral primary PCI.

Results: Data analysis revealed mean age was 57.6 yrs, male preponderance (80%),diabetes (35%),hypertension (61%), Smoking (61%), average total ischaemic time 7.6 +/- 3.78 hours, average presentation delay 6.26 +/- 3.77 hrs, average door to balloon time 60 +/- 14 mins, SVD (69%), LAD involvement(60%). Multivariate regression analysis without considering any other factor showed predicted LV Systolic function one month post PPCI to be 74.08%. Mean LVEF: 58.2%. Most interesting observation is 0.63% reduction of predicted LVEF for each hour increment of ischaemic time. Also LAD occlusion is associated with 4.91% reduction of predicted LVEF compared to other vessel(s) involvement. All the 48 patients who underwent PPCI not only survived but also had good LV Systolic function one month post PPCI.

Conclusion: Ischaemic time is an important predictor of LV Systolic function even after PPCI. lncrease in ischaemic time by one hour reduces predicted LVEF by 0.63%.Presentation delay is mostly responsible for total ischaemic time in India.