Background Pulmonary arterial hypertension (PAH) is of great clinical significance in connective tissue diseases (CTD) because of its high mortality. In particular, prognosis of PAH associated with systemic sclerosis (PAH-SSc) is extremely poor compared with PAH associated with other CTD (PAH-non-SSc). The reason, however, remains to be elucidated. Cardiac magnetic resonance imaging (CMRI) has been shown to provide additional data on right heart catheterization (RHC), enabling deep understanding of the hemodynamic state of PAH.
Objectives To detect the difference in hemodynamic state between PAH-SSc and PAH-non-SSc by performing CMRI.
Methods This is a retrospective study consisting of 32 consecutive patients with CTD who had undergone RHC and CMRI within one week.
Results Of the 32 patients, 31 were female and 14 had SSc. The mean age at the time of RHC and CMRI performed was 54.2±12.8 years. Mean pulmonary arterial pressure (mPAP) was 38.2±10.2 mmHg. CMRI detected right ventricular ejection fraction (RVEF), right ventricular end-diastolic volume index (RVEDVI), left ventricular ejection fraction (LVEF) and left ventricular end-diastolic volume index (LVEDVI). RVEF negatively correlated with mPAP (r = -0.439, p=0.012) and pulmonary vascular resistance (PVR) (r = -0.508, p=0.003). The ratio of RVEDVI/LVEDVI, which represents ventricular stiffness and interplay, positively correlated with mPAP (r =0.398, p=0.024) and PVR (r =0.540, p=0.001). In SSc patients, mPAP was significantly lower (p=0.036) while RVEF and the ratio of RVEDVI/LVEDVI were not different from non-SSc patients. In addition, if the ratio of RVEDVI/LVEDVI was divided by mPAP, it was significantly higher in SSc patients (p=0.027), suggesting an increased ventricular stiffness and a resultant left ventricular compression in PAH-SSc. Of 17 patients, including 10 SSc and 7 non-SSc, who underwent follow-up CMRI during treatment, the ratio of RVEDVI/LVEDVI elevated in two patients. Both patients had SSc and died within two years from development of PAH. Of note, in one particular patient, the ratio of RVEDVI/LVEDVI actually elevated despite the improvement of RHC data including mPAP and PVR. Overall, increased trend in the ratio of RVEDVI/LVEDVI during the follow-up period was an apparent prognostic factor compared with its stable or decrease trend (p=0.006).
Conclusions Our data indicate that altered ventricular dimension detected by CMRI represents the disease-specific cardiac involvement of PAH-SSc and may reflect prognosis. Performing CMRI before and during treatment of PAH-SSc is helpful in terms of predicting prognosis and choice of the best therapeutic strategy.
Disclosure of Interest A. Noguchi: None declared, S. Yasuda: None declared, M. Kono: None declared, M. Kato: None declared, K. Oku: None declared, T. Bohgaki: None declared, O. Amengual: None declared, T. Horita: None declared, T. Sato: None declared, I. Tsujino: None declared, M. Nishimura: None declared, T. Atsumi Grant/research support from: Chugai Pharmaceutical Co., Ltd. Eisai Co., Ltd. Bristol-Myers Squibb Co. Astellas Pharma Inc. Daiichi Sankyo Co., Ltd. Mitsubishi Tanabe Pharma Co, Speakers bureau: Astellas Pharma Inc. Mitsubishi Tanabe Pharma Co.