Methamphetamine-Associated Pulmonary Arterial Hypertension Is Associated With Worse Right Ventricular Function Than Idiopathic Pulmonary Arterial Hypertension: A Matched Study.

BACKGROUND

Methamphetamine is increasingly recognized as a cause of pulmonary arterial hypertension (PAH). This study examines whether non-invasively measured metrics of right heart function, right atrial (RA) and right ventricular (RV) strain, are more impaired in methamphetamine-associated PAH (MA-PAH) compared with idiopathic PAH (IPAH).

METHODS

A retrospective cohort analysis of 51 patients with MA-PAH matched for mean pulmonary artery pressure (mPAP) with 51 patients with IPAH followed at the pulmonary hypertension clinic at the University of Utah was performed. Invasive hemodynamics and echocardiographic measures of right heart function, including RA strain and RV free wall strain, were compared.

RESULTS

Compared to the matched IPAH group, MA-PAH patients had lower cardiac index (2.04 ± 0.84 vs. 2.52 ± 1.07 L/min/m2, p = 0.016) and higher pulmonary vascular resistance (PVR; 11.8 ± 6.8 vs. 8.9 ± 4.8 Wood units, p = 0.018). The MA-PAH group had larger RA maximal and minimal volume, lower RA reservoir strain (26.4 ± 11.7 vs. 33.4 ± 14.8 %, p = 0.011), more significant RV chamber dilation, and lower fractional area change (FAC; 21.1 ± 11.1 % vs. 34.5 ± 11.8 %, p < 0.001), compared to the IPAH group. RV e' was lower in MA-PAH (6.5 ± 2.8 cm/s vs. 8.3 ± 4.3 cm/s, p = 0.021), suggesting worse RV diastolic function and RV free wall strain was significantly more reduced compared to patients with I-PAH (17.0 ± 6.5 vs. 22.3 ± 7.2 %, p < 0.001). There were no differences in 5-year survival (p = 0.26), 6MW distance including stratification for males and females (p = 0.249 in females, p = 0.279 in males), and rehospitalization rates within 5 years of diagnosis (p = 0.70).

DISCUSSION: Despite a similar mPAP, patients with MA-PAH had more RA dilation, RV dilation, lower RV systolic/diastolic function, and worse RA and RV mechanics as assessed by strain compared to patients with I-PAH. Our findings suggest that, in addition to causing remodeling of the pulmonary vasculature, methamphetamine may have a direct cardiotoxic effect on the right heart.