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From Affiliated Egyptian Universities and Cardiology Centers

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Background: The results of the PASSION (1) and the TYPHOON (2) trials cannot be generalized to all patients with acute MI, since high-risk patients were excluded. This called us for a study to evaluate the safety and efficacy of DES when used in clinical practice in an unselected ‘Real-world’ population with acute MI.
Methods This prospective registry was conducted on 227 consecutive patients referred for PCI using either drug eluting stent (DES) (n= 94) or bare metal stent (BMS) (n= 133) after acute myocardial infarction (MI). Patients referred for PCI within the first 72 hours after acute MI with elevated CK-MB, or after that during their hospital stay in the presence of angiographically visible thrombus were considered for this study. All patients were enrolled regardless of the clinical or anatomical presentation, including patients admitted with cardiogenic shock and patients with unprotected left main lesions. Myocardial perfusion imaging was done for all patients with symptoms of myocardial ischemia at follow up. It was done to 21.3% of the DES group and to 24.1% of the BMS groups (P >0.05). Angiographic follow-up beyond the initial procedure was clinically driven, and was not routinely performed in all patients. Follow up angiography was done to 12.8% of the DES and to 22.6% of the BMS (P <0.05). Patients without follow-up angiography were free of symptoms, and no adverse events were observed among those patients.
Results :Baseline clinical characteristics were comparable, except that LV EF <35% was more prevalent among BMS (20.3% vs. 12.7%; P <0.05). There were substantial differences in clinical presentation between the two groups, the mean time from symptom onset till PCI was significantly less among BMS (39 vs. 57 hrs; P <0.001). PCI within 12 hours was done more frequently among BMS (57.8% vs. 29.7%; P <0.001). Also the incidence of cardiogenic shock was significantly higher among BMS (15% vs. 5.3%; P <0.05). On the other hand, angiographic lesion profiles were less favourable in DES group (type C: 75% DES vs. 57% BMS, P <0.01). In fact, DES were used more often to manage long lesions (57% vs. 32%; P <0.001), and small vessels (11% vs. 2%; P <0.01). The mean RVD was lower (2.84 vs. 3.1mm; P <0.05) and the mean lesion length was higher among DES group (22.9 vs. 19.1 mm; P <0.05). Patients in the DES group received fewer GP IIb/IIIa inhibitors (54% vs. 81%; P <0.001). Among patients who received a DES, the average implanted stent length was greater (29 mm vs. 22 mm; P <0.05), and more lesions per patient were stented (1.4 vs. 1.1; P <0.05). Although in-hospital and 30 days events were similar in both groups, after a median follow-up of 12.6 months for the DES, and 11.9 months for the BMS group (P >0.05), the incidence of cardiac death (6.8% vs. 2.1%; P <0.05), TLR (9.8% vs. 3.2%; P <0.05), TVR (9.8% vs. 4.3%; P <0.05) and TFV (21.8% vs. 9.6%; P <0.01) were significantly higher among BMS. The primary end point of the study-cumulative MACE was also higher among BMS (23.3% vs. 10.6%; P <0.01). There was no significant difference between the two groups regarding stent thrombosis (ST) (4.2% in DES, vs. 4.5% in BMS; P >0.05) or non fatal MI (4.2% in DES, vs. 7.5% in BMS; P >0.05). The antiproliferative properties of DES are demonstrated by lower late loss (0.68 vs. 1.16; P <0.05). This was accompanied by reduction in angiographic restenosis (4.3% vs. 12.1%; P <0.05). In patients who developed restenosis, a pattern of focal restenosis was found in 75% of restenotic patients treated with DES, conversely, a diffuse pattern of restenosis was found more often in restenotic patients treated with BMS (69 %; P <0.05). Stent type was the only factor significantly associated with the pattern of restenosis, with a positive association between BMS and diffuse restenosis (P <0.05). After adjustment, the use of BMS was not independently associated with a higher risk of death, however cardiogenic shock, intra-aortic balloon pump use (P <0.001), left ventricular ejection fraction <35% and Diabetes Mellitus (P <0.05) were independent significant predictors of death. Multivariable analysis showed that DM, RVD <2.5 mm, lesion length >30 mm, type C lesion, and use of BMS were significantly associated with TLR (P <005).

Conclusions: This study showed that in an unselected real-world population, no evidence exists of a decreasing efficacy of DES in patients with acute MI. Also by reducing the rates and improving the pattern of restenosis, DES may reduce subsequent occurrence of death.
Keywords: Drug eluting vs bare metal stent.