Pulmonary embolism (PE) patients face a 3% chance of developing chronic thromboembolic pulmonary hypertension (CTEPH). But high-risk patients may never know they are in jeopardy because follow-up imaging studies may not be ordered, and clinicians often fail to spot the condition or take action to treat it, according to the results of a retrospective cohort study recently published in the Annals of the American Thoracic Society.

CTEPH, a serious disorder that arises following some cases of PE, is defined as hypertension in the arteries of the lungs caused by blood clots. Left untreated, it can cause right ventricular heart failure and death. The authors note that previous studies have found that screening for CTEPH is uncommon, and even after screening, the condition may go unrecognized. Study authors therefore conducted a retrospective study examining follow-up trajectories of patients who had experienced acute PE, as a way to identify “missed opportunities” for diagnosing of the disorder.

For the study, researchers retrospectively identified patients admitted to Intermountain Medical Center in Salt Lake City, UT, with a diagnosis of acute PE who met study criteria from April 1, 2014 to March 31, 2016. Overall, 658 patients diagnosed with PE (median age, 64; 54% female) were included in the analysis. A prior history of venous thromboembolism was found in almost 17% (109/658) of participants. 


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Patient data were examined for a follow up period determined by the study’s end date that ranged from  36 to 60 months. Diagnostic studies done during the follow-up period were used to rank participants as having low, intermediate, or high probability of developing CTEPH. During follow-up, however, just 302 (46%) patients underwent further testing, with either transthoracic echocardiogram (TTE), ventilation-perfusion, or computed tomography pulmonary angiogram, even though the medical center had a thrombosis clinic and pulmonary hypertension care center. Most saw a primary care physician rather than a pulmonary hypertension specialist. 

After exclusions, 97 of 559 patients (17%) with follow-up testing were placed in the “possible CTEPH” category, 5 (0.9%) were classified as “confirmed CTEPH,” and 37 were tagged “CTEPH ruled out.” The researchers observed that only about half (42/97) of all “possible CTEPH” patients underwent enough testing to confirm or rule out the condition. They concluded that only about 10% (55/559) of the overall group had experienced inadequate evaluation for CTEPH but noted that additional patients likely exhibited symptoms of CTEPH but never were tested during follow-up, adding to the number of inadequate evaluations.

The 0.9% of patients classified as having “confirmed CTEPH” corresponds to percentages seen in some studies but falls below the 3% incidence obtained in more reliable prospective screening studies, the investigators said. A 3% incidence in the current study would have translated to an additional 12 patients in whom CTEPH should have been detected. 

The researchers acknowledged that their dataset and study design did not permit them to recommend specific ways of addressing the shortcomings found in their study, but suggested a computerized support tool could be programmed to signal intermediate or high-risk TTEs, warning that the PE survivor is at risk of CTEPH.

“Our study demonstrates that the medical system often fails to recognize and act upon abnormal imaging studies indicating the potential presence of CTEPH in a PE survivor,” the authors assert. “These lapses may partially explain the low observed incidence of CTEPH in real-world scenarios compared to the expected incidence from prospective screening studies.”

Disclosure: Dr. Elliott declared an affiliation with a pharmaceutical company. The remaining authors declare no competing interests.

Reference

Cirulis MM, Knox DB, Stoddard GJ, et al. The CTEPH trajectories study: assessment of follow-up after acute pulmonary embolism to identify missed opportunities for CTEPH diagnosis. Ann Am Thorac Soc. Published online April 11, 2022. doi:10.1513/AnnalsATS.202112-1316RL