Study examines long-term prognosis of CTEPH after blood clot

Death risk nearly doubled in CTEPH occurring within 2 years after a VTE

Margarida Maia, PhD avatar

by Margarida Maia, PhD |

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Developing chronic thromboembolic pulmonary hypertension (CTEPH) within two years after a venous thromboembolism (VTE), which occurs when a blood clot forms in a vein, nearly doubles the risk of long-term death, according to a large study from Denmark.

Researchers also observed that all types of pulmonary hypertension (PH) were linked to a higher risk of death, and that the risk was even higher when PH was caused by problems with the heart’s left side and lung disease.

“Our findings provide information on the prognostic impact of PH after VTE and highlight the importance of identifying and treating both VTE and co-morbid [co-existing] conditions leading to PH,” the researchers wrote.

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The study, “Long-Term Prognostic Impact of Pulmonary Hypertension After Venous Thromboembolism,” was published in The American Journal of Cardiology.

CTEPH may develop from a pulmonary embolism, which occurs when a blood clot gets stuck in a blood vessel of the lungs, where it can block blood flow and increase blood pressure.

Many people with VTE also develop other types of PH due to the presence of co-existing conditions such as left heart disease and lung disease. VTE may increase the risk of dying, but there’s limited data about how developing PH affects long-term death.

To get an accurate estimate of the risk of long-term death in people with PH who had a previous VTE, the researchers drew on data of all Danish adults who remained alive two years after a VTE from 1995 to 2020. This totaled 129,040 people.

Of these, 1,078 had a diagnosis of PH within these two years, and were followed up for a median 5.9 years. Their median age was 71 years, and 4,713 (44%) were men. Most (85%) had experienced a pulmonary embolism, and the remaining 165 (15%) experienced deep vein thrombosis, a blood clot in a deep vein, usually the leg.

When the researchers grouped the patients per PH type, 148 (14%) had PH due to left heart disease (group 2), 157 (14%) had PH due to lung disease (group 3), and 195 (18%) had CTEPH (group 4). The remaining 578 (54%) had unclassified PH.

10-year span

Mortality, or death rate, during follow-up was higher among people with PH than among those without PH. Within a year, 12% of people with PH had died versus 5% of people without PH. Over a span of 10 years, mortality was 61% versus 38% in the two groups.

All-cause mortality, or the risk of dying from any cause, was about two times as high in people with PH. Having PH due to left heart disease increased the risk by 2.62 times. For those with PH due to lung disease, the risk was even higher (3.98 times), while for those with CTEPH, the risk was nearly doubled (1.88 times).

“The mortality rate was increased approximately twofold for CTEPH, threefold for PH associated with left-sided cardiac disease, and fourfold for PH associated with lung diseases,” the researchers wrote.

When the researchers looked at cardiovascular mortality, or death from a disease of the heart and blood vessels, they found the risk was about three times as high for people with PH due to left heart disease or lung disease, but not for those with CTEPH.

In general, having PH was not linked to an increased risk of cancer-related death. Only those who developed PH due to lung disease had an increased (2.86 times higher) risk of cancer-related death.

“All PH subgroups were associated with increased mortality, but the excess mortality rate was higher for PH associated with left-sided cardiac disease and lung diseases than for CTEPH,” the researchers concluded.

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