Percutaneous coronary intervention-related time delay, patient's risk profile, and survival benefits of primary angioplasty vs lytic therapy in ST-segment elevation myocardial infarction.

BACKGROUND: Previous reports have suggested an impact of patient's risk profile and percutaneous coronary intervention (PCI)-related time delay on the benefits of primary angioplasty as compared with fibrinolysis. However, several factors, such as inappropriate interpretation and definition of delays, missing currently available trials, and arguable risk-benefit analysis, limit the value of these reports. Thus, the aim of the current review is to assess whether the prognostic impact of PCI-related time delay may vary according to patient's risk profile, presentation delay, and type of lytic therapy.
METHODS: We obtained results from all randomized trials comparing fibrinolysis and primary angioplasty in ST-segment elevation myocardial infarction. The literature was scanned by formal searches of electronic databases (MEDLINE and CENTRAL) for papers published from January 1990 to April 2007. The following key words were used: randomized trial, myocardial infarction, reperfusion, primary angioplasty, rescue angioplasty, fibrinolysis, thrombolysis, duteplase, reteplase, tenecteplase, and alteplase. Major clinical end point assessed was mortality at 30-day follow-up. The relationship between mortality benefits from primary angioplasty, patient's risk profile, and PCI-related time delay was evaluated by using a weighted least-square regression in which results from each trial were weighted by the square root of the number of patients of each trial.
RESULTS: A total of 27 trials were finally included, with 4399 patients randomized to primary angioplasty and 4474 patients randomized to fibrinolysis. The relationship between the benefits from primary angioplasty and PCI-related time changed according to risk profile. The higher the risk profile, the larger the reduction in mortality benefits from primary angioplasty as compared with fibrinolysis per each 10 minutes of PCI-related time delay (0.75%, 0.45%, and 0%, in high-, medium-, and low-risk patients, respectively). Furthermore, the impact was observed only in trials enrolling patients within the first 6 hours from symptom onset.
CONCLUSIONS: When primary angioplasty is selected as reperfusion strategy, all efforts should be attempted to shorten time-to-treatment, particularly in medium- or high-risk patients and in early presenters, because in these patients, a larger loss of mortality benefits as compared with fibrinolysis is observed per each 10 minutes of PCI-related time delay.