Original Communication
Pulmonary embolism and sudden–unexpected death: Prospective study on 2477 forensic autopsies performed at the Institute of Legal Medicine in Seville

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Abstract

Pulmonary embolism (PE) and deep venous thrombosis (DVT) are clinical manifestations of the same entity, venous thromboembolic disease (VTD). In approximately 25% of patients, the first manifestation of PE is sudden–unexpected death.

We carried out a prospective study at the forensic pathology service of the Institute of Legal Medicine in Seville with the aim to know the incidence of PE as well as to describe the epidemiological, pathological and clinical characteristics of these deaths and associated risk factors.

In the study period (32 months) 32 cases of PE were registered from a total of 2447 completed autopsies. Three cases were considered accidental deaths and the remaining 29 cases were sudden natural deaths, which represents 1.3% of the total autopsies, 2.6% of natural deaths and 4.3% of sudden deaths. Nineteen cases (59%) were men (mean age 50.3 ± 13.8, range 22–74 years) and 13 cases (41%) were women (mean age 50.3 ± 13.8, range 18–87 years). In 78% of cases death occurred at home or during transfer to a health care centre, mainly during the fall or winter (69%) and between 8 a.m. and 4 p.m. (47%). Pulmonary infarction was associated only in two cases (6%). Nine cases (28%) had been immobilized but only three (9%) received anticoagulant therapy. Surgical interventions had occurred in seven cases (22%). A history of psychiatric pathology was found in 31%. Overweight or obesity was found in 75%. The most frequent symptoms prior to death were dyspnea (31%) and chest pain (19%), and 19% of patients were examined in an Emergencies Department for symptoms compatible with deep vein thrombosis and/or PE, but this diagnosis was not suspected in any case.

PE frequently makes its first appearance as sudden death. In addition to the classic risk factors, this study highlights that 75% of the cases were overweight/obese as well as 31% having had a history of psychiatric disorders and treatment as to support that this association should be considered as a risk factor. PE continues to be under diagnosed in Emergencies Department patients, which hinders the application of adequate therapeutic measures to prevent these deaths.

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.

Section snippets

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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