[Death after ST-elevation myocardial infarction in patients treated with fibrinolytic therapy, angioplasty, or conventional therapy. A post-mortem study to verify cardiac rupture as a cause of death].

BACKGROUND

Experimental clinical observations suggest that fibrinolysis (FL) in acute myocardial infarction, even though reducing global mortality, is associated with an increasing incidence of death in the first 24-48 h. The responsible mechanism is not yet known, although available evidence supports heart rupture as the possible cause.

METHODS

We studied 154 patients at autopsy who died of cardiac causes from January 1, 1994 to December 31, 2005 among a cohort of 2260 patients who were admitted for ST-elevation myocardial infarction. They were divided into three therapeutic groups-- FL, coronary angioplasty (PTCA) and conventional therapy (CT)--in order to assess the incidence of cardiac rupture and compare it with the other causes of cardiac death.

RESULTS

Of the 896 patients (39.7%) who were treated with FL, 57 (6.4%) died; of the 804 (35.6%) treated with PTCA, 40 (5.05%) died, and of the 560 (24.7%) treated with CT, 57 (10.2%) died (p < 0.05 in the two first groups vs CT). We studied at autopsy 154 patients (mortality 6.7%). The mean admission delay was 5.05 h in the FL group, 7.04 h in the PTCA group, and 7.05 h in the CT group. Cardiac death occurred on average after 13 h in the FL group, after 15 h in the PTCA group, and after 19 h in the CT group. The cause of death was due to cardiac rupture in 56 patients (36.5%), to shock in 55 patients (35.7%), to electromechanical dissociation in 29 patients (18.8%), and to cardiac failure in 14 patients (9%). In the FL and PTCA groups, cardiac rupture was the major, and also the earliest (10 e 12 h, respectively), cause of death, whereas in the CT group cardiac shock (13 h) was the major cause of death. Anterior myocardial infarction (n = 104, 65%) was more prevalent in deceased patients, whereas inferior myocardial infarction was found in the other 50 cases (35%). Cardiac rupture was more prevalent in anterior myocardial infarction. In the FL and PTCA groups, histological examination showed unusual hemorrhagic infiltration in the necrotic areas with presence of leukocytes.

CONCLUSIONS

Our study shows that cardiac rupture is the major cause of death in patients with ST-elevation myocardial infarction treated with FL and PTCA, suggesting that mechanical and lythic reperfusion injury, in coagulative necrosis, may represent a further cause of cardiac rupture that occurs early or within the first hours.