Original article
General thoracic
Longitudinal Follow-Up of Six-Minute Walk Distance After Pulmonary Endarterectomy

https://doi.org/10.1016/j.athoracsur.2010.11.061Get rights and content

Background

The 6-minute walk test is a useful tool to assess functional outcome after pulmonary endarterectomy (PEA) in chronic thromboembolic pulmonary hypertension. However, little is known about the longitudinal dynamics in functional improvement. We performed a longitudinal follow-up of 6-minute walk distance, New York Heart Association functional class, and echocardiography after PEA.

Methods

We studied 71 patients with chronic thromboembolic pulmonary hypertension who underwent PEA. A 6-minute walk test and echocardiography were performed before PEA, at 3 months after, and at annual follow-up. At the time of this report, 52 patients had returned for 2-year follow-up, 32 for 3-year follow-up, 23 for 4-year follow-up, and 11 for 5-year follow-up.

Results

Preoperatively, the 6-minute walk distance (6-MWD) correlated with hemodynamic severity of disease (mean pulmonary artery pressure: r = −0.55, p < 0.001); total pulmonary resistance: r = −0.59, p < 0.001) After PEA, 6-MWD increased from 440 ± 109 to 524 ± 83 meters at 1 year (n = 71, p < 0.001). Further improvement was observed from 523 ± 87 meters at 1 year to 536 ± 91 meters at 2 years (n = 52, p < 0.012). After 2 years, no further improvement was observed. At 1 year, the change in 6-MWD from baseline correlated significantly with the change observed in pulmonary hemodynamics. Changes in 6-MWD and hemodynamics were more pronounced in patients with residual pulmonary hypertension after PEA, despite the worse absolute outcome.

Conclusions

In patients with chronic thromboembolic pulmonary hypertension, 6-MWD showed a gradual improvement up to 2 years after PEA. Patients with residual pulmonary hypertension benefited most from treatment, despite the worse absolute outcome.

Section snippets

Patients and Methods

The research protocol for this study was approved by the local Institutional Review Board, and the study was conducted in accordance with the principles of the Declaration of Helsinki. On inclusion, all patients were asked to consent to collection of their data. However, because the analyses performed for the present study used anonymized data that had been registered for research purposes, the need for informed consent was waived.

Patient Characteristics

Between January 2003 and January 2009, 96 patients with CTEPH underwent PEA in our hospital. Most of the 85 patients with pulmonary arterial hypertension at rest had moderate to severe pulmonary hypertension, with a mean mPAP of 43.7 ± 10.9 mm Hg and a mean total pulmonary resistance (TPR) of 806 ± 387 dynes · s · cm−5. Eleven additional patients with exercise-induced pulmonary hypertension presented with disabling impairment of exercise tolerance and had angiographic evidence for proximal

Comment

We assessed the longitudinal postoperative functional recovery of patients with CTEPH up to 5 years after PEA. Although NYHA functional class and sPAP improved within the first 3 months after PEA and remained constant thereafter, the 6-MWD showed a gradual improvement over a 2-year follow-up period. Interestingly, patients with residual pulmonary hypertension after PEA showed more improvement in both 6-MWD and hemodynamics, despite their worse absolute outcome.

As hypothesized, restoration of

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      It does no harm to the patients and is easy to measure. In fact, some studies have chosen the 6MWT for the functional outcome assessment after PEA.30–33 These studies did not show a strong relationship between the 6MWT value and RHC data.

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