Right Ventricular Dyssynchrony Before and After Pulmonary Thromboendarterectomy in Patients with Chronic Thromboembolic Pulmonary Hypertension

ABSTRACT

Background: Left ventricular dyssynchrony has been studied extensively, but this is not the case with right ventricular (RV) dyssynchrony. Our aim was to investigate RV dyssynchrony through 2D speckle strain imaging in patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and after pulmonary thromboendarterectomy (PTE).

Methods: We measured 2D peak RV strain (%) of the RV free-wall and time to peak strain (ms) of its three freewall segments (base, mid, and apex) in 127 consecutive CTEPH patients (51 ± 14 years, 59% female) with adequate images pre- and post-PTE. RV strain was calculated using Epsilon Imaging EchoInsight® software. RV dyssynchrony was measured using two methods: the standard deviation of peak systolic strain and the standard deviation of time (ms) to peak strain (RVDT) between the three RV free-wall segments.

Results: Mean RV free wall strain did not change significantly after PTE (−11.4 ± 5.7 to −11.2 ± 5.6%, p = 0.67). However, RV dyssynchrony improved dramatically after surgery in RVDP and RVDT (9.4 ± 6.2 to 5.4 ± 3.8%, p < 0.0001; 103 ± 65 to 56 ± 65 ms, p < 0.0001, respectively).

Conclusions: There was a significant decrease in the standard deviation of the mean peak systolic strain and time to peak strain (dyssynchrony) of the three RV free-wall segments after PTE. The cause of this more uniform contraction of the right ventricle after PTE is unclear, but could stem from the marked change in pulmonary vascular resistance and mean pulmonary arterial pressure in this population.

KEYWORDS:

• Chronic thromboembolic pulmonary hypertension
• dyssynchrony
• pulmonary hypertension
• right ventricular strain

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Supplemental video

Video 1

These are representative echocardiograms of a patient who underwent PTE.

(a) The left and right panels show four chamber views before and after surgery, respectively. The blue lines help indicate the directionality and magnitude of free wall strain. The numbers indicate the peak strain value of the individual free wall segments.

(b) The strain graphs correspond to each free-wall segment before (top panel) and after (bottom panel) PTE. These graphs show the representative improvement in RVD (splay between the function plots) by both time to peak strain (RVDT) and magnitude of peak strain (RVDP) between the three free wall segments.

(c) Figurative heat-map representation of RV free wall strain. The shades of red coincide with negative strain and shades of blue correlate with positive strain. The post-operative RV free wall shows a more uniform coloration and thus correlates with a more uniform contraction of the RV free wall.

Disclosure statement

No potential conflicts of interest were reported by the authors.