Characteristics of Pulmonary Artery Pressure Waveform for Differential Diagnosis of Chronic Pulmonary Thromboembolism and Primary Pulmonary Hypertension

Objectives. The accurate diagnosis of chronic pulmonary thromboembolism (CPTE) is prerequisite for life-saving surgical interventions. To help in the differential diagnosis of CPTE and primary pulmonary hypertension (PPH), we characterized the configuration of the pulmonary artery pressure waveform. Background. Because CPTE predominantly involves the proximal arteries, whereas PPH involves the peripheral arteries, we hypothesized that patients with CPTE would have stiff or high resistance proximal arteries, whereas those affected by PPH would have high resistance peripheral arteries. These differences in the primary lesions would make arterial pulsatility relative to mean pressure larger in CPTE than in PPH. Methods. In 34 patients with either CPTE (n = 22) or PPH (n = 12) whose pulmonary systolic pressure was ≥50 mm Hg, we measured pulmonary artery pressure using fluid-filled system that included balloon-tipped flow-directed catheter. Results. To quantify the magnitude of pulsatility relative to mean pressure, we normalized pulse pressure by mean pressure, hereinafter referred to as fractional pulse pressure (PPf). PPf was markedly higher in CPTE than in PPH (mean [± SD] 1.41 ± 0.20 and 0.80 ± 0.18, respectively, p < 0.001) and was diagnostic in separating the two groups without overlap. Similarly, the coefficient of variation of pulmonary artery pressure also separated the two groups without overlap (0.45 ± 0.06 and 0.25 ± 0.06, respectively, p < 0.001). Fractional time to half the are under the pressure curve separated the two groups reasonably well (0.35 ± 0.02 and 0.43 ± 0.03, respectively, p < 0.001). Conclusions. The analysis of pulsatility of pulmonary artery pressure is useful in the differential diagnosis of CPTE and PPH.