Contribution of the left atrial remodeling to the elevated pulmonary capillary wedge pressure in patients with WHO Group II pulmonary hypertension.

BACKGROUND: The contribution of progressive left atrial (LA) enlargement to elevated pulmonary capillary wedge pressure (PCWP) in patients with WHO Group II pulmonary hypertension (PH) has not been well studied. We hypothesized that progressive LA enlargement is associated with increased PCWP.

METHODS: A cross-sectional retrospective cohort consisted of 166 patients with HF and WHO Group II PH, confirmed by right heart catheterization (RHC). LA anteroposterior dimension and volume were measured on TTE. PCWP and other hemodynamic parameters were measured by RHC. Univariate and multivariate logistic regression models were used for analysis.

RESULTS: LA enlargement was associated with advanced age, increased BMI, and LV ejection fraction < 40%. PCWP was progressively increased in patients with dilated LA: 16.9 ± 7.4 mmHg in normal LA, 17.6 ± 7.2 mmHg in mildly dilated LA, 22.6 ± 6.3 mmHg in moderately and 22 ± 7.6 in severely dilated LA (p < 0.001). In multiple logistic regression, after adjustment for echocardiographic and clinical variables, severe LA enlargement was independently predictive of elevated PCWP (OR 3.468; 95% CI 1.046-11.504; p = 0.042). After excluding significant mitral regurgitation, progressive LA dilatation was associated with higher PCWP V-wave amplitude: from 21.3 ± 10.4 mmHg in patients with normal LA size, to 30.9 ± 11.7 mmHg in moderately dilated and 31.0 ± 11.6 mmHg in severely dilated LA (p < 0.001).

CONCLUSIONS: In patients with HF and WHO Group II PH, progressive LA enlargement was independently associated with elevated PCWP. After excluding significant mitral regurgitation, LA enlargement was also associated with increased V-wave amplitude, indicative of decreased atrial compliance.