Impacts of acute severe pulmonary regurgitation on right ventricular geometry and contractility assessed by tissue-Doppler echocardiography.

AIMS: Little is known of the impact of acute right ventricular (RV) volume overload on RV function. We assessed the impact of acute severe pulmonary regurgitation (PR) on global and regional RV function by applying novel quantitative echocardiographic markers of myocardial performance in an animal model. METHODS AND RESULTS: Transthoracic echocardiography, including tissue-Doppler echocardiography for the evaluation of regional longitudinal function, was performed immediately before and after induction of severe PR by deployment of a stent in the pulmonary valve annulus of 32 farm pigs. Acute PR was associated with significant changes in RV geometry illustrated by an increase in RV diameter and area by 22 and 32%, respectively, P < 0.001 for both, and the eccentricity index increased by 21% in end-diastole, P < 0.0001. RV radial function as assessed by RV short-axis fractional shortening increased by 18%, P = 0.03, whereas other measures of RV ejection fraction by longitudinal function remained unchanged. There were no changes in the longitudinal basal myocardial isovolumic acceleration, peak systolic velocity, strain rate, or strain. CONCLUSION: The RV seems to accommodate well to acute severe PR. No changes in global or regional longitudinal contractility or deformation were observed despite significant changes in the cardiac chamber geometry. An increase in radial shortening may imply that the RV compensates by increasing radial contraction as an adjunct to dilatation.

Effects of chronic severe pulmonary regurgitation and percutaneous valve repair on right ventricular geometry and contractility assessed by tissue Doppler echocardiography.

INTRODUCTION: Pulmonary regurgitation (PR) following repair of right ventricular (RV) outflow obstruction is related to slowly progressive RV dilatation and heart failure and will eventually require surgical intervention, but optimal timing of pulmonary valve replacement is challenging. Tissue Doppler based quantification of RV contractility may offer additional information in the management of these patients. METHODS: In a porcine animal model free PR was induced by percutaneous stenting of the pulmonary valve orifice (N = 23). After 1, 2, or 3 months of free PR percutaneous pulmonary valve replacement (PPVR) was performed. Tissue Doppler derived measures of global and regional myocardial contractility were obtained by transthoracic echocardiography, and compared to a sham-operated control group (N = 9). RESULTS: Free PR is associated with RV dilatation (RV end-diastolic area increased from 15 ± 3 to 23 ± 7 cm(2) /m(2) , P < 0.0001) and a decrease in RV fractional area change from 62 ± 10% to 57 ± 12%, P = 0.08, with no impact of duration of free PR. The isovolumic acceleration, regional strain, and strain rate were unchanged after free PR and after PPVR. No consistent relation of echocardiographic measures of contractility and response to PPVR could be identified. CONCLUSION: Echocardiographic measures of RV contractility remained unchanged, despite significant RV remodeling following chronic PR and PPVR persistently induced significant recovery in the majority of the animals. These results may imply that Tissue Doppler based measures of RV contractility may not be sufficiently sensitive to be a suitable adjunct to conventional echocardiography in the follow-up of patients with free PR in order to optimize timing of valve replacement.

Right ventricular outflow tract reconstruction for pulmonary regurgitation after repair of tetralogy of Fallot. Preliminary results.

BACKGROUND: Pulmonary regurgitation after tetralogy of Fallot (ToF) repair is associated with right ventricular dilatation, failure and arrhythmia. Timing and technique for re-intervention remain controversial. METHODS: Our recent approach is to reconstruct the dilated right ventricle outflow tract (RVOT) as a fibro-muscular sleeve to support a pulmonary homograft valve conduit in orthotopic position. Indication is based on clinical and magnetic resonance (MR) criteria. We reviewed all patients who underwent RVOT reconstruction between January 2004 and February 2005. There were seven children (mean age 14+/-2 years) operated 13+/-2 years after ToF repair, and 12 adults (mean age 30+/-15 years) operated 23+/-10 years after ToF repair. Exercise testing and MR evaluation prior to surgery and at 1 year postoperative follow-up were compared. RESULTS: There was no operative mortality. At 1 year, pulmonary regurgitation was mild or less in 16/19 patients. Right ventricular (RV) end-diastolic (158+/-51 to 103+/-36ml/m(2), p<0.001) and end-systolic volumes (85+/-42 to 49+/-24ml/m(2), p=0.001) fell significantly. Importantly, effective RV stroke volume (43+/-10 to 48+/-7ml/m(2), p=0.019) and left ventricular (LV) stroke volume (43+/-7 to 47+/-7ml/m(2), p=0.009) increased significantly. The mean RV/LV end-diastolic volume ratio fell markedly in both children and adults (2.22+/-0.62 to 1.38+/-0.52). However, no improvement in maximal VO(2) on exercise was noted in either group. CONCLUSIONS: RVOT reconstruction restored valve function, improved RV dimensions and left and right stroke volumes. Maximal exercise capacity did not improve in either children or adults.

Long-term importance of right ventricular outflow tract patch function in patients with pulmonary regurgitation.

OBJECTIVE: Chronic pulmonary regurgitation (PR) has deleterious effects on right ventricular (RV) function in repaired tetralogy of Fallot (ToF). However, there are little data regarding right ventricular outflow tract (RVOT) contractile dysfunction in response to chronic PR and on both RV and LV volumes and function. METHODS: We retrospectively identified consecutive patients with PR who were referred for magnetic resonance imaging quantification of "free PR" detected on echocardiography between 2003 and 2008. Patients had ToF and a transannular patch procedure (n = 30, 25.1 ± 1.2 years) or PR resulting from valvar pulmonary stenosis treated with surgical or percutaneous valvotomy (n = 30, 26.6 ± 1.8 years). RESULTS: The ToF and the PS groups were well matched for age at scan, age at repair surgery in ToF or initial valvotomy in PS, duration of exposure to PR, body surface area, heart rate, PR fraction, net forward pulmonary artery flow, and main and branch pulmonary artery dimensions. Severe PR fractions were identified in both groups (ToF: 40% ± 1% vs PS: 37% ± 2%, P = .2). Indexed RV and LV end-diastolic volumes were similar for both ToF and PS groups (RV end-diastolic volume index: 137 ± 6 mL/m(2) vs 128 ± 5 mL/m(2), P = .2, and LV end-diastolic volume index: 72 ± 2 mL/m(2) vs 67 ± 2 mL/m(2), P = .1, respectively). RV mass was also similar between groups (95 ± 5 g vs 81 ± 6 g, respectively, P = .08). However, indexed RV and LV end-systolic volumes were consistently higher in ToF when compared with PS (RV end-systolic volume index: 70 ± 5 mL/m(2) vs 54 ± 3 mL/m(2), P < .01, and LV end-systolic volume index: 29 ± 1 mL/m(2) vs 22 ± 1 mL/m(2), P < .01, respectively). These changes were reflected in lower biventricular systolic function in patients with ToF when compared with PS (RV ejection fraction: 52% ± 1.5% vs 59% ± 1%, P < .001, and LV ejection fraction: 61% ± 1% vs 67 ± 1%, P < .001, respectively). Although RV transannular plane systolic excursion was not significantly different between the groups (P = .86), the RV outflow tract was considered contractile in only 50% of patients with ToF compared with 93% of patients with PS (P = .0004). RV volumes and function were similar when only patients with contractile RV outflow tracts were compared. CONCLUSIONS: RV outflow tract patch dysfunction in repaired ToF is responsible for higher end-systolic volumes and thus lower global measures of ventricular systolic function. These findings were not evident in cases of PS treated with valvotomy with comparable amount of PR. These observations highlight the importance of the initial repair surgery in ToF for late outcomes.