Background: Currently, there are many parameters with proven prognostic significance in pulmonary hypertension (PH). Recently, the parameters defining right ventricular–pulmonary artery coupling (RVPAC) have gained clinical importance. In our study, we investigated the prognostic potential of previously known single echocardiographic parameters and new parameters reflecting RVPAC in patients with precapillary PH. Objective: Our study aimed to evaluate the prognostic value of selected echocardiographic parameters and the neutrophil–lymphocyte ratio (NLR) in adults with precapillary PH. Methods: This study included 39 patients (74% women; average age, 63 years) with precapillary PH: pulmonary arterial hypertension (PAH) and chronic thromboembolic PH (CTEPH). The mean follow-up period was 16.6 ± 13.3 months. Twelve patients (31%) died during the observation time. We measured several echocardiographic parameters, which reflect right ventricular function, pulmonary hemodynamics, and RVPAC. To assess disease progression and the patient’s functional capacity, the World Health Organization functional class (WHO FC) was determined. The patient’s physical capacity was also evaluated using the 6 min walk test (6MWT). The analysis included values of the N-terminal prohormone brain natriuretic peptide (NT-proBNP) and NLR. Results: TAPSE × AcT and TAPSE/sPAP were shown to statistically and significantly correlate with PH predictors, including WHO-FC, 6MWT, and NT-proBNP. Univariate Cox proportional hazards regression analysis revealed that AcT, TAPSE, mPAP, TAPSE/sPAP, RAP, TRPG/AcT, TAPSE × AcT, and NLRs are good predictors of mortality in patients with PH. In addition, the ROC curve analysis showed that TAPSE × AcT is a better predictor of PH-related deaths than TAPSE/sPAP and TAPSE alone. In our study, patients with TAPSE × AcT values < 126.36 had shorter survival times (sensitivity = 72.7%; specificity = 80.0%). Conclusions: TAPSE × AcT is a novel, promising, and practicable echocardiographic parameter reflecting RVPAC, which is comparable to TAPSE/sPAP. Moreover, TAPSE × AcT can be a useful parameter in assessing the severity and prognosis of patients with precapillary PH.