Imaging the Right Heart-Pulmonary Circulation Unit

Establishment of a canine model of pulmonary arterial hypertension induced by dehydromonocrotaline and ultrasonographic study of right ventricular remodeling

OBJECTIVE

Pulmonary arterial hypertension (PAH) means high blood pressure in the lungs. We aimed to observe the right ventricular size, wall thickness and characteristic functional changes and their associations with PAH in an established model of beagle dogs, and to explore convenient, reliable and sensitive ultrasound indicators for assessing right ventricular remodeling.

METHODS

Twenty healthy beagle dogs (8-10 kg) were randomly divided into control group (N-dimethylformamide, n = 10) and dehydromonocrotaline (DHMCT) group (DHMCT, n = 10). N-dimethylformamide or DHMCT was injected through a catheter into the right atrium, and then right heart catheterization, routine echocardiography and two-dimensional speckle tracking imaging (2D-STI) were performed before modeling (0 weeks) and 8, 14 weeks after modeling. Hemodynamic parameters and right ventricular function-related ultrasound data were acquired. At the end of the experiment, the animals were killed and the lung tissues were taken for HE staining. Left and right ventricular walls were separated and weighed respectively, and right ventricular hypertrophy index (RVHI) was measured. The associations of the routine ultrasound data and 2D-STI data at each time point with hemodynamic parameters and RVHI were analyzed.

RESULTS

At 0, 8 and 14 weeks, gradual decreases in the right ventricular global longitudinal strain (RVLS) were found in DHMCT group. RVH occurred in DHMCT group, and DHMCT group had a significantly higher RVHI than that of control group (49.83 ± 4.83% vs. 39.80 ± 1.40%, P < .001) and larger pulmonary artery media thickness. RVLS had significant positive correlations with RVSP (r = 0.74, P < .001), mRVP (r = 0.72, P < .001), PASP (r = 0.75, P < .001), mPAP (r = 0.72, P < .001) and PVR (r = 0.68, P < .001). There was a significant positive correlation between RVLS and RVHI (r = 0.74, P < .001).

CONCLUSION

The right ventricular function in PAH can be effectively assessed by echocardiography, and RVLS measured by 2D-STI sensitively reflects right ventricular remodeling following PAH.

EXPRESS: Statement on imaging and pulmonary hypertension from the Pulmonary Vascular Research Institute (PVRI)

Pulmonary hypertension (PH) is highly heterogeneous and despite treatment advances it remains a life-shortening condition. There have been significant advances in imaging technologies, but despite evidence of their potential clinical utility, practice remains variable, dependent in part on imaging availability and expertise. This statement summarizes current and emerging imaging modalities and their potential role in the diagnosis and assessment of suspected PH. It also includes a review of commonly encountered clinical and radiological scenarios, and imaging and modeling-based biomarkers. An expert panel was formed including clinicians, radiologists, imaging scientists, and computational modelers. Section editors generated a series of summary statements based on a review of the literature and professional experience and, following consensus review, a diagnostic algorithm and 55 statements were agreed. The diagnostic algorithm and summary statements emphasize the key role and added value of imaging in the diagnosis and assessment of PH and highlight areas requiring further research.

Early Right Ventricular Dysfunction in Highly Selected (Totally Free from Cardiovascular Risk Factors and Other Comorbidities) Human Immunodeficiency Virus Patients: A Pilot Study with Advanced Echocardiography

Objective:

Human immunodeficiency virus (HIV) infection may also be associated with cardiac dysfunction, thus negatively affecting patients’ morbidity and mortality. This preliminary study aimed at evaluating whether bi-and three-dimensional (3D) strain echocardiographic facilities were able to identify alterations in the right ventricular (RV) function in highly selected – because free from cardiovascular risk factors and other comorbidities – HIV patients.

Materials and Methods:

Eight of these specific HIV patients (age: 32.0 ± 3.6 years; 7 months) treated with highly active antiretroviral therapy (HAART) were enrolled and compared with 8 sex-, age-, and cardiovascular risk profile-matched healthy individuals. All underwent clinical evaluation and transthoracic echocardiography coupled with tissue Doppler, two-dimensional (2D), and 3D speckle tracking imaging to examine their RV function.

Results:

All standard echocardiographic parameters resulted in the normal range, with no significant differences between HIV and controls. On the contrary, 2D longitudinal strain (16.1% ±1.6% vs. 17.8% ±0.9%, P = 0.02) and Global 3D strain (28.5% ±3.6% vs. 33.5% ±1.9%, P = 0.0002) were reduced in the HIV group. Moreover, Global 3D strain values showed a direct correlation with RV fractional area change values (r = 0.66, P = 0.005).

Conclusions:

2D longitudinal and 3D Global strain can identify an early asymptomatic RV impairment in HIV patients free from other risk factors and comorbidities. These findings seem to imply that also in treated with HAART and well-controlled HIV patients an early asymptomatic systolic RV dysfunction is present, as a distinctive and separated pathological entity compared with classic HIV-related pulmonary arterial hypertension and left ventricular dysfunction. In these patients, RV dysfunction is not revealed by standard echocardiography.