The relationship of patent infarct-related artery with time to thrombolysis in patients with ST-Segment Elevation Myocardial Infarction.

Objective: To find out the spectrum of TIMI flow in the infarct-related artery amongst the patients who are thrombolysed in different time zones from pain to thrombolysis. Study Design: Prospective, Comparative study. Setting: Department of Cardiology, Ayub Medical Teaching Institute. Period: August 2022 to January 2023. Methods: A total of 122 consecutive patients with their first STEMI thrombolysed within 12 hours of pain were included in the study. Data on demographics, medical history, and physical examination findings were collected using a specially designed proforma. Patients were assessed for the success or failure of thrombolysis according to our prespecified criteria. All patients underwent coronary angiography as per our institutional protocol. TIMI flow in the infarct-related artery was documented. Results were analyzed using SPSS statistical software version 21.0. Results: 77% were male, 43% were hypertensives, one-third of patients were smokers, and 26% were diabetic. Anterior STEMI was seen in 38% of patients, while 57% had inferior STEMI. 46% of patients were thrombolysed within 3 hours, 33% within 3 to 6 hours, 10% between 6 to 9 hours, and 11% between 9 to 12 hours. The rate of TIMI III flow was the highest (89%) in patients thrombolysed within 3 hours, 85% in patients thrombolysed between 3 to 6 hours, 83% in patients thrombolysed between 6 to 9 hours, and 78% in patients thrombolysed between 9 to 12 hours. There were significantly more patients with ≥70% resolution of ST-segment elevation amongst those thrombolysed within 3 hours since the onset of pain, compared to those thrombolysed after 9 hours since the onset of pain. Conclusion: The highest frequency of TIMI III flow was seen when patients were thrombolysed within 3 hours. The rate of TIMI III flow decreased as the time to thrombolysis increased from less than 3 hours to 12 hours. However, the differences in TIMI III flow were not statistically significant. There was a statistically significant relationship between the degree of ST-segment resolution and time since pain to thrombolysis.