Ventricular-Arterial Coupling From 3D Echocardiography May Predict Systemic Sclerosis Prognosis

Ventricular-arterial coupling (VAC) measured by 3-dimensional (3D) echocardiography may be impaired in patients with systemic sclerosis (SSc) and may play a prognostic role in SSc, according to study results published in Pharmaceuticals.  

Traditional measurements including end-diastolic diameter, fractional shortening, and left ventricle ejection fraction are load-dependent and do not systematically reflect the contractile state of the myocardium. In contrast, VAC, which is expressed as a ratio between arterial elastance (Ea) and end-systolic elastance (Ees) of the left ventricle, reflects global cardiovascular efficiency.

The current study aimed to characterize VAC in patients with SSc and compare VAC and VAC-related indices between patients with a limited and diffuse cutaneous form of the disease.

Patients with SSc with primary myocardial involvement who underwent 3D echocardiography were included in the current study. All volume measurements were collected using 3D electrocardiography, owing to its higher accuracy, precision, and reproducibility compared to the 2D method.  

A total of 65 patients (mean age, 56±14 years; 83% women) were enrolled in the study. Pressure-volume curve (P-VC) parameters were compared between patients and healthy control individuals. No difference was seen in left ventricle diastolic dimension, wall thickness, mass index, left ventricular end-systolic volume (LVESV), left ventricular end-diastolic volume (LVEDV), stroke volume (SV), left ventricular ejection fraction (LVEF), and systolic and diastolic blood pressure. The Ea and Ees were elevated in patients with SSc vs control participants (3.95+1.8 vs 2.99+0.7 mm Hg/mL; P =.002 and 2.28+0.11 vs 1.73+0.07 mm Hg/mL; P =.001, respectively); however, VAC was comparable between the groups (P =.59).

P-VC parameters were compared between patients with a VAC of 0.63 or less (n=34) and those with a VAC more than 0.63 (n=31). Compared with patients with lower VAC, those with higher VAC had significantly higher LVESV and reduced LVEF (P <.0001 for both), indicating poorer cardiac function.

P-VC parameters were compared between patients with limited and diffuse SSc. Patients with diffuse scleroderma showed higher SV, LVEDV, VAC, and potential energy; however, left ventricle efficiency was lower. Notably, in patients with diffuse scleroderma, the Ees correlated with Ea, but the correlation line was shifted upward and to the left. For the same Ea value, patients with diffuse scleroderma presented with a lower Ees, indicating inadequate contractility.

Results from a multivariable logistic regression analysis showed that a VAC greater than 0.63 was linked to LVESV (odds ratio [OR], 1.076, 95% CI, 1.012-1.144; P =.02) and time from diagnosis (OR, 1.057; 95% CI, 1.008-1.127; P =.04), after adjusting for age and sex.

A VAC of more than 0.63 was independently associated with major adverse cardiac events (MACEs; hazard ratio, 2.5; 95% CI, 1.13-5.7; P =.01), after adjustment for age, sex, pulmonary hypertension, diffuse cutaneous SSc, and interstitial lung disease. In addition, a global chi-square analysis showed that a VAC of greater than 0.63 was predictive of MACEs (P =.02).

Overall, study results indicate that VAC may be impaired in patients with SSc; VAC may be significantly higher in patients with diffuse cutaneous SSc than in those with limited cutaneous SSc, despite normal LVEF, and worsen in relation to disease duration; and VAC may predict MACEs in patients with SSc.

Study limitations included the relatively small sample size and its monocentric design. In addition, although statistically significant differences were observed, the study may have been underpowered, and the exact mechanisms underlying changes in myocardial contractility were not determined.

Researchers concluded, “Further prospective studies are warranted to ascertain whether early intervention can improve outcomes in patients with “abnormal” VAC.”

Reference

Tona F, Zanatta E, Montisci R, et al. Higher ventricular-arterial coupling derived from three-dimensional echocardiography is associated with a worse clinical outcome in systemic sclerosis. Pharmaceuticals. 2021;14(7):646. doi:10.3390/ph14070646