目的:右心室(RV)衰竭是肺动脉高压(PH)患者死亡的主要原因之一。由于PH的多样性和RV的复杂几何形状,常规超声心动图参数不包括在风险分层和预后评估的随访中。RV流出道速度时间积分(RVOTVTI)是一个简单的,非侵入性的肺流量估计和RV每搏输出量的超声心动图替代。在这项研究中,我们旨在确定RVOTVTI在PH患者中的预后价值。
方法:63例特发性PAH(IPAH)(n=23),回顾性纳入结缔组织疾病相关性PAH(CTD相关PAH)(n=19)和慢性血栓栓塞性肺动脉高压(CTEPH)(n=21)。全面的二维超声心动图评估,包括RVOT-VTI测量,在随访和纽约心脏协会功能班(NYHAFC)期间进行,记录6min步行距离(6MWD)和脑钠肽(BNP)水平。
结果:整个队列的中位年龄为63岁(52-68岁),47例(74.6%)患者为女性。中位随访时间为20个月(11-33),20例(31.7%)患者在此期间死亡。BNP值较高[317(210-641)vs161(47-466),P=0.02],非幸存者组6MWD值较低[197.5±89.5vs339±146.3,P<0.0001],非幸存者组的NYHA-FC较差(P=0.02)。在超声心动图数据中,三尖瓣环平面收缩期偏移(TAPSE)(15.4±4.8vs18.6±4.2,P=0.01)和RVOTVTI(11.9±4.1vs17.2±4.3,P<0.0001)值较低,而右心房面积(RAA)(26.9±10.1vs22.2±7.1,P=0.04)值较高。预测死亡率的RVOTVTI曲线下面积为0.82[95%置信区间(CI)0.715-0.940,P<0.0001],最佳截断值为14.7cm,灵敏度为80%,特异性为77%。RVOTVTI≤14.7cm的受试者的生存率明显较低(log-rankP<0.0001)。RVOTVTI≤14.7cm患者1年生存率为70%,50%在2年内,3年为29%,5年为21%。全因死亡率的单变量决定因素为BNP[危险比(HR)1.001(1.001-1.002),P=0.001],6MWD[HR0.994(0.990-0.999),P=0.012]和NYHA-FCIII-IV[HR3.335(1.103-10.083),P=0.03],TAPSE[HR0.838(0.775-0.929),P=0.001],RAA[HR1.072(1.013-1.135),P=0.016]和RVOTVTI[HR0.819(0.740-0.906),P<0.0001]。发现RVOTVTI是死亡率的唯一独立决定因素[HR0.857(0.766-0.960),P=0.008]。
结论:RVOTVTI降低预示PH患者的死亡率,RVOTVTI每降低1mm,死亡率风险增加14.3%。该参数可作为这些患者随访中的附加参数,特别是当6MWD和NYHA-FC无法确定时。
OBJECTIVE: Right ventricular (RV) failure is one of the leading causes of death in patients with pulmonary hypertension (PH). Conventional echocardiographic parameters are not included in risk stratification and follow-up for prognostic assessment due to PH\'s diverse nature and the RV\'s complex geometry. RV outflow tract velocity time integral (RVOT VTI) is a simple, non-invasive estimate of pulmonary flow and an echocardiographic surrogate of RV stroke volume. In this study, we aimed to define the prognostic value of RVOT VTI in PH patients.
METHODS: Sixty-three subjects with idiopathic PAH (IPAH) (n = 23), connective tissue disease-associated PAH (CTD-associated PAH) (n = 19) and chronic thromboembolic pulmonary hypertension (CTEPH) (n = 21) were retrospectively included. A comprehensive two-dimensional echocardiographic evaluation, including RVOT-VTI measurement, was performed during the follow-up and the New York Heart Association functional class (NYHA FC), 6 min walk distance (6MWD) and brain natriuretic peptide (BNP) levels were recorded.
RESULTS: The median age of the whole cohort was 63 years (52-68), and 47 (74.6%) of the patients were women. The median follow-up period was 20 months (11-33), and 20 (31.7%) patients died in this period. BNP values were higher [317 (210-641) vs 161 (47-466), P = 0.02], and 6MWD values were lower [197.5 ± 89.5 vs 339 ± 146.3, P < 0.0001] in the non-survivor group, and the non-survivor group had a worse NYHA-FC (P = 0.02). Among echocardiographic data, tricuspid annular plane systolic excursion (TAPSE) (15.4 ± 4.8 vs 18.6 ± 4.2, P = 0.01) and RVOT VTI (11.9 ± 4.1 vs 17.2 ± 4.3, P < 0.0001) values were lower whereas right atrial area (RAA) (26.9 ± 10.1 vs 22.2 ± 7.1, P = 0.04) values were higher in the non-survivor group. The area under curve of the RVOT VTI for predicting mortality was 0.82 [95% confidence interval (CI) 0.715-0.940, P < 0.0001], and the best cut-off value was 14.7 cm with a sensitivity of 80% and specificity of 77%. Survival was significantly lower in subjects with RVOT VTI ≤ 14.7 cm (log-rank P < 0.0001). Survival rates for patients with RVOT VTI ≤ 14.7 cm were 70% at 1 year, 50% at 2 years, %29 at 3 years and 21% at 5 years. The univariate determinants of all-cause mortality were BNP [hazard ratio (HR) 1.001 (1.001-1.002), P = 0.001], 6MWD [HR 0.994 (0.990-0.999), P = 0.012] and NYHA-FC III-IV [HR 3.335 (1.103-10.083), P = 0.03], TAPSE [HR 0.838 (0.775-0.929), P = 0.001], RAA [HR 1.072 (1.013-1.135), P = 0.016] and RVOT VTI [HR 0.819 (0.740-0.906), P < 0.0001]. RVOT VTI was found to be the only independent determinant of mortality [HR 0.857 (0.766-0.960), P = 0.008].
CONCLUSIONS: The decreased RVOT VTI predicts mortality in patients with PH and each 1 mm decrease in RVOT VTI increases the risk of mortality by 14.3%. This parameter might serve as an additional parameter in the follow-up of these patients especially when 6MWD and NYHA-FC could not be determined.