Right ventricular wall-motion changes after infant open heart surgery--a tissue Doppler study

Venous waveform analysis detects acute right ventricular failure in a rat respiratory arrest model

BACKGROUND

Peripheral intravenous analysis (PIVA) has been shown to be more sensitive than central venous pressure (CVP) for detecting hemorrhage and volume overload. We hypothesized that PIVA is superior to CVP for detecting right ventricular (RV) failure in a rat model of respiratory arrest.

METHODS

Eight Wistar rats were studied in accordance with the ARRIVE guidelines. CVP, mean arterial pressure (MAP), and PIVA were recorded. Respiratory arrest was achieved with IV Rocuronium. PIVA utilizes Fourier transform to quantify the amplitude of the peripheral venous waveform, expressed as the "f1 amplitude". RV diameter was measured with transthoracic echocardiography.

RESULTS

RV diameter increased from 0.34 to 0.54 cm during arrest, p = 0.001, and returned to 0.33 cm post arrest, p = 0.97. There was an increase in f1 amplitude from 0.07 to 0.38 mmHg, p = 0.01 and returned to 0.08 mmHg, p = 1.0. MAP decreased from 119 to 67 mmHg, p = 0.004 and returned to 136 mmHg, p = 0.50. There was no significant increase in CVP from 9.3 mmHg at baseline to 10.5 mmHg during respiratory arrest, p = 0.91, and recovery to 8.6 mmHg, p = 0.81.

CONCLUSIONS

This study highlights the utility of PIVA to detect RV failure in small-caliber vessels, comparable to peripheral veins in the human pediatric population.

IMPACT

Right ventricular failure remains a diagnostic challenge, particularly in pediatric patients with small vessel sizes limiting invasive intravascular monitor use. Intravenous analysis has shown promise in detecting hypovolemia and volume overload. Intravenous analysis successfully detects right ventricular failure in a rat respiratory arrest model. Intravenous analysis showed utility despite utilizing small peripheral venous access and therefore may be applicable to a pediatric population. Intravenous analysis may be helpful in differentiating various types of shock.

Left and Right Ventricular Impairment Shortly After Correction of Tetralogy of Fallot

Surgical repair of Tetralogy of Fallot (ToF) is usually performed in the first months of life with low early postoperative mortality. During long-term follow-up, however, both right (RV) and left ventricular (LV) performances may deteriorate. Tissue Doppler imaging (TDI) and speckle tracking echocardiography (ST) can unmask a diminished RV and LV performance. The objective of the current study was to assess the cardiac performance before and shortly after corrective surgery in ToF patients using conventional, TDI and ST echocardiographic techniques. Thirty-six ToF patients after surgery were included. Transthoracic echocardiography including TDI and ST techniques was performed preoperatively and at hospital discharge after surgery (10 days to 4 weeks after surgery). Median age at surgery was 7.5 months [5.5-10.9]. Regarding the LV systolic function there was a significant decrease in interventricular septum (IVS) S' at discharge as compared to preoperatively (pre IVS S' = 5.4 ± 1.4; post IVS S' = 3.9 ± 1.2; p < 0.001) and in global longitudinal peak strain (GLS) (pre = - 18.3 ± 3.4; post = - 14.2 ± 4.1; p = 0.003); but not in the fractional shortening (FS). Both conventional and TDI parameters showed a decrease in diastolic function at discharge. Tricuspid Annular Plane Systolic Excursion and RV S' were significantly lower before discharge. When assessing the RV diastolic performance, only the TDI demonstrated a RV impairment. There was a negative correlation between age at surgery and postoperative LV GLS (R = - 0.41, p = 0.031). There seems to be an impairment in left and right ventricle performance at discharge after ToF corrective surgery compared to preoperatively. This is better determined with TDI and ST strain imaging than with conventional echocardiography.

Right ventricular function during exercise in children after heart transplantation

Aims

Right ventricular (RV) dysfunction is a common problem after heart transplant (HTx). In this study, we used semi-supine bicycle ergometry (SSBE) stress echocardiography to evaluate RV systolic and diastolic reserve in paediatric HTx recipients.

Methods and results

Thirty-nine pediatric HTx recipients and 23 controls underwent stepwise SSBE stress echocardiography. Colour tissue doppler imaging (TDI) peak systolic (s') and peak diastolic (e') velocities, myocardial acceleration during isovolumic contraction (IVA), and RV free wall longitudinal strain were measured at incremental heart rates (HR). The relationship with increasing HR was evaluated for each parameter by plotting values at each stage of exercise versus HR using linear and non-linear regression models. At rest, HTx recipients had higher HR with lower TDI velocities (s': 5.4 ± 1.7 vs. 10.4 ± 1.8 cm/s, P < 0.001; e': 6.4 ± 2.2 vs.12 ± 2.4 cm/s, P < 0.001) and RV IVA values (IVA: 1.2 ± 0.4 vs. 1.6 ± 0.8 m/s2, P = 0.04), while RV free wall longitudinal strain was similar between groups. At peak exercise, HR was higher in controls and all measurements of RV function were significantly lower in HTx recipients, except for RV free wall longitudinal strain. When assessing the increase in each parameter vs. HR, the slopes were not significantly different between patients and controls except for IVA, which was lower in HTx recipients.

Conclusion

In pediatric HTx recipients RV systolic and diastolic functional response to exercise is preserved with a normal increase in TDI velocities and strain values with increasing HR. The blunted IVA response possibly indicates a mildly decreased RV contractile response but it requires further investigation.

Comparison of valvar and right ventricular function following transcatheter and surgical pulmonary valve replacement

OBJECTIVE

Trans-catheter (TC) pulmonary valve replacement (PVR) has become common practice for patients with right ventricular outflow tract obstruction (RVOTO) and/or pulmonic insufficiency (PI). Our aim was to compare PVR and right ventricular (RV) function of patients who received TC vs surgical PVR.

DESIGN

Retrospective review of echocardiograms obtained at three time points: before, immediately after PVR, and most recent.

PATIENTS

Sixty-two patients (median age 19 years, median follow-up 25 months) following TC (N = 32) or surgical (N = 30) PVR at Yale-New Haven Hospital were included.

OUTCOME MEASURES

Pulmonary valve and right ventricular function before, immediately after, and most recently after PVR.

RESULTS

At baseline, the TC group had predominant RVOTO (74% vs 10%, P < .001), and moderate-severe PI was less common (61% vs 100%, P < .001). Immediate post-procedural PVR function was good throughout. At last follow-up, the TC group had preserved valve function, but the surgical group did not (moderate RVOTO: 6% vs 41%, P < .001; >mild PI: 0% vs 24%, P = .003). Patients younger than 17 years at surgical PVR had the highest risk of developing PVR dysfunction, while PVR function in follow-up was similar in adults. Looking at RV size and function, both groups had a decline in RV size following PVR. However, while RV function remained stable in the TC group, there was a transient postoperative decline in the surgical group.

CONCLUSIONS

TC PVR in patients age <17 years is associated with better PVR function in follow-up compared to surgical valves. There was a transient decline in RV function following surgical but not TC PVR. TC PVR should therefore be the first choice in children who are considered for PVR, whenever possible.

A method for stereoscopic strain analysis of the right ventricle by digital image correlation during coronary bypass surgery: short communication

Perioperative cardiosurgical management of volume therapy remains one of the challenging tasks in cases of patients with severe heart disease. Early detection of congestive cardiac failure prevents subsequent low output and worse outcome. An effective method for controlling extracorporeal circulation is created by developing a non-invasive intraoperative method for right ventricular strain analysis through digital image contrast correlation.