Original CommunicationPulmonary embolism and sudden–unexpected death: Prospective study on 2477 forensic autopsies performed at the Institute of Legal Medicine in Seville
Introduction
Pulmonary embolism (PE) and deep venous thrombosis (DVT) are clinical manifestations of the same entity, venous thromboembolic disease (VTD). The clinical diagnosis of PE is difficult in a significant percentage of patients and is frequently missed, explaining its high mortality rate.[1], [2] In approximately 25% of patients, the first manifestation of PE is sudden–unexpected death.[3], [4]
Thrombus formation is based in the classical Virchow´s triad: Stasis, endothelial damage and abnormalities in the circulating blood. The predisposition to form clots may be due to acquired or genetic risk factors. Acquired risk factors include immobilization, increasing age, surgery, malignancies, obesity, pregnancy, puerperium, oral contraceptives and long-haul air travels.[2], [5] Inherited conditions (hereditary thrombophilias) include factor V Leiden leading to activated protein C resistance, prothrombin gene mutation, and deficiences of antithrombin (I, II and III), protein C or protein S.[6], [7], [8], [9], [10]
PE is a well-known entity in forensic pathology and is described in most standard Forensic Pathology textbooks[11], [12] as well as in some recent studies from medical examiners offices.[7], [8], [9], [10] There are also other studies on clinical autopsies on previously hospitalized patients.[13], [14] However, most previous series are retrospective; on the contrary, the main strength of our study is that it has been conducted prospectively, in a consecutive series of forensic autopsies.
The objective of this study is to analyze the incidence of PE as the cause of sudden death in the reference population of the forensic pathology service of the Institute of Legal Medicine, Seville, determining the absolute number of these deaths and their percentage in relation to the total number of deaths and specifically to the natural deaths. The epidemiological, pathological and clinical characteristics of these deaths are described as well as the presence of risk factors.
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Material and methods
According to the Spanish Legislation, all cases of violent or suspected deaths must undergo a medico-legal investigation with the aim to know the cause and the manner of the death. These cases include: homicides, suicides or accidents of any kind, sudden–unexpected deaths, deaths in custody, deaths at home or in hospital when the cause is unknown and no death certificate is issued, and patients under the care of a physician, at home or in hospital, when the family present a complaint asking for
Results
Incidence of PE as cause of sudden death: In the study period 2477 forensic autopsies were performed, with 55% (1363) corresponding to violent deaths (homicides, suicides or accidents) and 45% (1114) to natural deaths. Six hundred and sixty-eight of the natural deaths (668/1114 = 60%) fulfilled the criteria of sudden death. There were 32 cases of death by PE, from which three cases were linked back to an initiating accidental injury and from a medico-legal point of view they were considered
Discussion
In this study, PE was the main cause of death in 1.2% of the total forensic autopsies. This percentage is within the previously reported range of 0.8%, obtained at the Office of the Chief Medical Examiner of New York8, and 2.5% referred to by the Department of Legal Medicine of the University of Kitasato.19 Studies carried out on series of hospital autopsies indicate a greater percentage of PE (between 3.9% and 5.8%)[13], [14], [20] than that obtained in forensic autopsies. This difference is
Conflict of interest statement
None.
Funding
This study was supported by the Thematic Networks Program of Cooperative Research: Characteristics of Sudden Death in Spain (FIS G078/03). Spanish Ministry of Health.
Ethical approval
Ethical approval by Valme University Hospital Ethical Committee on June 24th 2002.
Acknowledgment
To Dr. Cristina Basso, Institute of Cardiovascular Pathology Padua Medical School, for her critical review of the manuscript.
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