Pulmonary pressure in the first twelve-months of live: What should we expect?

Introduction

Mean pulmonary artery pressure (mPAP) ≥ 20 mmHg defines pulmonary hypertension (PH).

Objective

Critically evaluate this cut-off in very young patients.

Methods

In total, 1129 consecutive patients had a reliable mPAP measurement between 1–12 months of life. These invasive measurements and their clinical history were reviewed.

Results

Age was mean ± SD 158 ± 100 days, weight 5.5 ± 1.9 kg. Patients with a palliated single ventricle anatomy 129/1129, peripheral PA-branch stenosis or MAPCAs 45/1129, PA-banding for open shunt 30/1129, or severe RVOTO 185/1129 were excluded. Of the remaining 726 patients 163/726 (22%) had mPAP < 20 mmHg while 563 (78%) had PH with mPAP ≥ 20 mmHg.

Overall, PH at TTE was the reason for invasive mPAP measurement in 236 patients and only 16/236 patients (7%) had a mPAP < 20 mmHg but 12/16 (75%) had a mPAP ≥ 18 mmHg. In the group with mPAP ≥ 20 mmHg PH persisted at 6-months in 109/236 (46%) (Fig. 1A) and in 68/236 (28%) at long-term follow-up (Fig. 1B). In the group with mPAP between 18 and 20 mmHg PH persisted at 6-months in 9/12 (75%) and in 3/12 (25%) at long-term follow-up. None of the patients with mPAP < 18 mmHg had PH at follow-up.

In patients with less than 3 months of age, PH at TTE was the reason for invasive mPAP measurement in 73/306 (23%) and only 3/73 patients (4%) had a mPAP < 20 mmHg, but 2/3 (75%) had a mPAP ≥ 18 mmHg. In the group with mPAP ≥ 20 mmHg PH persisted at 6-months in 34/70 (48%) (Fig. 2A) and in 34/70 (48%) at long-term follow-up (Fig. 2B). In the group with mPAP between 18 and 20 mmHg PH persisted at 6-months in 2/2 (100%) and in 2/2 (100%) at long-term follow-up. None of those with mPAP < 18 mmHg had PH at follow-up.

Conclusion

Pulmonary hypertension defined by mPAP ≥ 20 mmHg is very common in this cohort of young patients, especially in case of suspected PH at echo. A different cut-off defined as 18 mmHg should be discussed in patients with less than 12-months.