Rationale:: Mechanisms of coronary occlusion in ST-elevation acute coronary syndrome are poorly understood. We have previously reported that neutrophil (polymorphonuclear cells [PMNs]) accumulation in culprit lesion site (CLS) thrombus is a predictor of cardiovascular outcomes. Objective:: The goal of this study was to characterize PMN activation at the CLS. We examined the relationships between CLS neutrophil extracellular traps (NETs), bacterial components as triggers of NETosis, activity of endogenous deoxyribonuclease, ST-segment resolution, and infarct size. Methods and Results:: We analyzed coronary thrombectomies from 111 patients with ST-elevation acute coronary syndrome undergoing primary percutaneous coronary intervention. Thrombi were characterized by immunostaining, flow cytometry, bacterial profiling, and immunometric and enzymatic assays. Compared with femoral PMNs, CLS PMNs were highly activated and formed aggregates with platelets. Nucleosomes, double-stranded DNA, neutrophil elastase, myeloperoxidase, and myeloid-related protein 8/14 were increased in CLS plasma, and NETs contributed to the scaffolds of particulate coronary thrombi. Copy numbers of Streptococcus species correlated positively with dsDNA. Thrombus NET burden correlated positively with infarct size and negatively with ST-segment resolution, whereas CLS deoxyribonuclease activity correlated negatively with infarct size and positively with ST-segment resolution. Recombinant deoxyribonuclease accelerated the lysis of coronary thrombi ex vivo. Conclusions:: PMNs are highly activated in ST-elevation acute coronary syndrome and undergo NETosis at the CLS. Coronary NET burden and deoxyribonuclease activity are predictors of ST-segment resolution and myocardial infarct size.

All available evidence today indicates that chronic thromboembolic pulmonary hypertension (CTEPH) is primarily caused by venous thromboembolism, as opposed to primary pulmonary vascularin situthrombosis. Both the initial magnitude of clot and pulmonary embolism (PE) recurrence may contribute to the development of CTEPH. Only few specific thrombophilic factors, such as phospholipid antibodies, lupus anticoagulant and elevated factor VIII, are statistically associated with CTEPH.A mechanistic view of CTEPH as a disease caused by obliteration of central pulmonary arteries by pulmonary emboli is too simplistic. Based on available data one may speculate that PE may be followed by a pulmonary vascular remodelling process modified by infection, immune phenomena, inflammation, circulating and vascular-resident progenitor cells, thyroid hormone replacement or malignancy. Both plasmatic factors (hypercoagulation, “sticky” red blood cells, high platelet counts and uncleavable fibrinogens) and a misguided vascular remodelling process contribute to major vessel and small vessel obliteration. Endothelial dysfunction and endothelial–mesenchymal transition may be important, but their precise roles remain obscure. There exists no animal model for CTEPH; therefore, experimentation in the future must include human tissues and clinical data in parallel.

Background— Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by intraluminal thrombus organization and fibrous obliteration of pulmonary arteries. Recently, associated medical conditions such as splenectomy, ventriculoatrial shunt for the treatment of hydrocephalus, permanent central intravenous lines, inflammatory bowel disease, and osteomyelitis were found to be associated with the development of CTEPH. The study aim was to define the impact of these novel risk factors on survival. Methods and Results— Between January 1992 and December 2006, 181 patients diagnosed with CTEPH were tracked with the use of our center’s customized computer database. A Cox regression model was used to examine relations between survival and associated medical conditions, age, sex, hemodynamic parameters, modified New York Heart Association functional class at diagnosis, CTEPH type, pulmonary endarterectomy, and anti-cardiolipin antibodies/lupus anticoagulant. During a median observation time of 22.1 (range, 0.03 to 152) months, the clinical end point of cardiovascular death or lung transplantation occurred in 48 cases (27%). Pulmonary endarterectomy (hazard ratio, 0.14; 95% CI, 0.05 to 0.41; P =0.0003), associated medical conditions (hazard ratio, 3.17; 95% CI, 1.70 to 5.92; P =0.0003), and pulmonary vascular resistance (hazard ratio, 1.02; 95% CI, 1.00 to 1.04; P =0.04) were predictors of survival. Thirty-day postoperative mortality (24% versus 9%) and the incidence of postoperative pulmonary hypertension (92% versus 20%) were substantially higher in patients with associated medical conditions. Conclusions— CTEPH-predisposing medical conditions, such as splenectomy, permanent central intravenous lines, and certain inflammatory disorders, predict poor survival in CTEPH.

Summary: Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by organized thromboemboli that obstruct the pulmonary vascular bed. Although CTEPH is a serious complication of acute symptomatic pulmonary embolism in 4% of cases, signs, symptoms and classical risk factors for venous thromboembolism are lacking. The aim of the present study was to identify medical conditions conferring an increased risk of CTEPH. We performed a case-control-study comparing 109 consecutive CTEPH patients to 187 patients with acute pulmonary embolism that was confirmed by a high probability lung scan. Splenectomy (odds ratio=13, 95% CI 2.7–127), ventriculoatrial (VA-) shunt for the treatment of hydrocephalus (odds ratio=13, 95% CI 2.5–129) and chronic inflammatory disorders, such as osteomyelitis and inflammatory bowel disease (IBD, odds ratio=67, 95% CI 7.9–8832) were associated with an increased risk of CTEPH.