Iloprost en la hipertensión pulmonar tromboembólica crónica

Clinical Study of Acute Vasoreactivity Testing in Patients with Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

The clinical significance of acute vasoreactivity testing (AVT) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) remains unclear. We analyzed changes in hemodynamics and oxygenation dynamics indices after AVT in patients with CTEPH using patients with pulmonary arterial hypertension (PAH) as controls.

METHODS

We analyzed retrospectively the results of AVT in 80 patients with PAH and 175 patients with CTEPH registered in the research database of Beijing Chao-Yang Hospital between October 2005 and August 2014. Demographic variables, cardiopulmonary indicators, and laboratory findings were compared in these two subgroups. A long-term follow-up was conducted in patients with CTEPH. Between-group comparisons were performed using the independent-sample t-test or the rank sum test, within-group comparisons were conducted using the paired t-test or the Wilcoxon signed-rank test, and count data were analyzed using the Chi-squared test. Survival was estimated using the Kaplan-Meier method and log-rank test.

RESULTS

The rates of positive response to AVT were similar in the CTEPH (25/175, 14.3%) and PAH (9/80, 11.3%) groups (P > 0.05). Factors significantly associated a positive response to AVT in the CTEPH group were level of N-terminal pro-brain natriuretic peptide (≤1131.000 ng/L), mean pulmonary arterial pressure (mPAP, ≤44.500 mmHg), pulmonary vascular resistance (PVR, ≤846.500 dyn·s-1·m-5), cardiac output (CO, ≥3.475 L/min), and mixed venous oxygen partial pressure (PvO2, ≥35.150 mmHg). Inhalation of iloprost resulted in similar changes in mean blood pressure, mPAP, PVR, systemic vascular resistance, CO, arterial oxygen saturation (SaO2), mixed venous oxygen saturation, partial pressure of oxygen in arterial blood (PaO2), PvO2, and intrapulmonary shunt (Qs/Qt) in the PAH and CTEPH groups (all P > 0.05). The survival time in patients with CTEPH with a negative response to AVT was somewhat shorter than that in AVT-responders although the difference was not statistically significant (χ2 =3.613, P = 0.057). The survival time of patients with CTEPH who received calcium channel blockers (CCBs) was longer than that in the group with only basic treatment and not shorter than that of patients who receiving targeted drugs or underwent pulmonary endarterectomy (PEA) although there was no significant difference between the four different treatment regimens (χ2 =3.069, P = 0.381).

CONCLUSIONS

The rates of positive response to AVT were similar in the CTEPH and PAH groups, and iloprost inhalation induced similar changes in hemodynamics and oxygenation dynamics indices. A positive response to AVT in the CTEPH group was significantly correlated with milder disease and better survival. Patients with CTEPH who cannot undergo PEA or receive targeted therapy but have a positive response to AVT might benefit from CCB treatment.

Acute improved hemodynamics following inhaled iloprost in chronic thromboembolic pulmonary hypertension

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) is a potential consequence to pulmonary embolism. The histologic picture is similar to idiopathic pulmonary hypertension (IPAH) suggesting that vascular remodeling also contributes to CTEPH. The treatment of choice is pulmonary endarterectomy. However, this treatment option is not adequate for all patients with CTEPH. Currently, no data exist on standard vasodilative therapy for CTEPH. Intravenous and oral prostanoids, both well-known vasodilators in IPAH, have been used with promising results, whereas the same has not been consistently observed for inhaled iloprost.

OBJECTIVE

In this study, we examined acute hemodynamic effects of inhaled iloprost in patients with CTEPH.

METHODS

In a prospective study, right heart catheterization was performed in 20 patients (mean age 56 years, New York Heart Association class II-IV) at the time of diagnosis of CTEPH. Pulmonary vascular resistance (PVR), mean pulmonary arterial pressure (mPAP), cardiac output (CO), mean systemic arterial pressure (MAP) and oxygen partial pressure (PaO(2)) were obtained before and 20 min after inhaling 5 mug iloprost. Subsequently, all patients were evaluated for pulmonary endarterectomy. Six patients were eligible for surgery.

RESULTS

Significant changes in pulmonary and systemic hemodynamics were observed following the inhalation of iloprost (before to after inhalation): PVR: 1,057 +/- 404.3 to 821.3 +/- 294.3 dyn.s.cm(-5), p < 0.0001; mPAP: 50.55 +/- 8.43 to 45.75 +/- 8.09 mm Hg, p = 0.0002; CO: 3.66 +/- 1.05 to 4.05 +/- 0.91 l/min, p < 0.0106. MAP and PaO(2) decreased significantly (MAP: 94.15 +/- 11.58 to 89.45 +/- 14.29 mm Hg, p = 0.0111; PaO(2): 7.33 +/- 1.17 to 6.64 +/- 1.25 kPa, p = 0.0260).

CONCLUSIONS

Hemodynamic changes directly following inhalation of iloprost suggest a significant contribution of a reversible component of vasoconstriction to pulmonary arterial hypertension in patients with CTEPH.