Oral Abstract Session
SCMR 22nd Annual Scientific Sessions
Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease that is characterized by an elevated mean pulmonary arterial pressure ≥25 mmHg at rest (1). Patients with PAH are often diagnosed at a late stage of the disease, wherefore it is important to develop new techniques to allow for early diagnosis and for detecting subtle changes in cardiac function, to improve outcome by optimizing treatment.
CMR images were acquired (1.5T and 3T, Achieva, Philips Healthcare, The Netherlands and 1.5T, Magnetom Aera, Siemens Healthcare, Germany) in 12 patients with PAH (55±22 years, 10 women) and 13 healthy controls (29±8 years, 6 women). RV and LV volumes were quantified by endocardial delineation in short axis cine images (Fig. 1a), in all time frames. 4D flow phase contrast images rendering time resolved velocity images in three dimensions were matched with the delineations (Fig. 1b). Henceforth, KE (KE=(mv2)/2, m: mass; v: velocity) of the blood was analyzed and calculated within both RV and LV during the 3 phases of the cardiac cycle; systole, early filling and late filling of diastole.
During systole, mean RV KE was reduced in patients with PAH compared to healthy controls (p=.007, Table 1). Mean RV KE did not differ significantly in early filling (p=.05), but during late filling, mean RV KE was increased in patients (p=.03, Table 1). When indexed to RV end-diastolic volume (RVEDV), RV KE differed in all three phases of the cardiac cycle (systole p=.008, early filling p=.03 and late filling p=.002, Table 2).
During systole and early filling, mean LV KE was reduced in patients with PAH compared to controls (p=.02 and p=.01, Table 1). Mean LV KE in late filling diastole was increased in patients (p=.006, Table 1).
Conclusion: KE is altered in patients with PAH compared to healthy controls. When indexed to EDV, the KE of systole and early filling were reduced in the RV but not in the LV in the PAH patients. However, the KE is increased in the late filling in both the left and right ventricle. The increased KE during late filling implies that atrial contraction is of importance to the filling of both ventricles in PAH. Hence, kinetic energy is a possible new marker of cardiac function in PAH.