RESUMO
Background: Mitral valve (MV) regurgitation (MR) is the second most frequent indication for valvular surgery in Europe. Right ventricular (RV) dysfunction is a common finding after cardiac surgery and might persist for years. The RV-function after MV surgery has been controversially discussed. We therefore aimed to evaluate early RV-performance in patients undergoing MV surgery. Methods: Between 09/2020 and 06/2022, ninety-two patients presenting with MR undergoing MV surgery were consented and prospectively included for evaluation. Echocardiographic evaluation was performed one day before surgery, one week after surgery and three months later. Primary endpoints reported RV-function changes including tricuspid annular plane systolic excursion (TAPSE), RV systolic prime (S') and fractional area change (FAC). Secondary endpoints included stability of MV repair, changes in left ventricular functions and early mortality. Results: Mean patients' age was 59.1±11.4 years. Fifty-five (59.7%) patients were male. Most of patients presented with severe (n=88; 95.7%) MR. Mean systolic pulmonary artery pressure was 35.6±15.7 mmHg. Moderate or severe pulmonary arterial hypertension (PAH) was present in 60 (65.2%) patients. Patients underwent either isolated MV surgery (n=67; 72.8%) or combined with tricuspid valve surgery (n=25; 27.2%). Minimal invasive surgery was performed in 26.1% (n=24) of the patients. Postoperative short-term follow-up at 3 months reported RV-dysfunction in 44.5% (n=41) of the patients as indicated by reductions in TAPSE & RV S' from 21.2±4.7 to 14±3.3 mm (P<0.001) and from 14.7±4.3 to 9.7±2.8 cm/s (P<0.001) respectively. The FAC reduction from 42.9%±9.6% to 42.2%±9.9% was non-significant (P=0.593) and no need for redo mitral or tricuspid valve surgery was reported. Finally, the presence and severity of preoperative PAH played significant roles for the incidence of RV dysfunction, P=0.021 and P=0.047, respectively. Minimal invasive surgical procedure significantly reduced the incidence of postoperative RV-dysfunction (P=0.013). Conclusions: Study early results report a significant reduction of RV-function after MV surgery as measured by TAPSE, & RV S', even when the FAC remains unchanged. Even though, this finding has limited prognostic implications during an uneventful surgical course.
RESUMO
Apolipoprotein E-deficient (apoE(-/-)) mice fed on Western diet are characterized by increased vascular resistance and atherosclerosis. Previously, we have shown that chronic angiotensin (Ang)-(1-7) treatment ameliorates endothelial dysfunction in apoE(-/-) mice. However, the mechanism of Ang-(1-7) on vasoconstrictor response to Ang II is unknown. To examine Ang-(1-7) function, we used apoE(-/-) and wild-type mice fed on Western diet that were treated via osmotic minipumps either with Ang-(1-7) (82 µg/kg per hour) or saline for 6 weeks. We show that Ang II-induced renal pressor response was significantly increased in apoE(-/-) compared with wild-type mice. This apoE(-/-)-specific response is attributed to reactive oxygen species-mediated p38 mitogen-activated protein kinase activation and subsequent phosphorylation of myosin light chain (MLC(20)), causing renal vasoconstriction. Here, we provide evidence that chronic Ang-(1-7) treatment attenuated the renal pressor response to Ang II in apoE(-/-) mice to wild-type levels. Ang-(1-7) treatment significantly decreased renal inducible nicotinamide adenine dinucleotide phosphate subunit p47phox levels and, thus, reactive oxygen species production that in turn causes decreased p38 mitogen-activated protein kinase activity. The latter has been confirmed by administration of a specific p38 mitogen-activated protein kinase inhibitor SB203580 (5 µmol/L), causing a reduced renal pressor response to Ang II in apoE(-/-) but not in apoE(-/-) mice treated with Ang-(1-7). Moreover, Ang-(1-7) treatment had no effect in Mas(-/-)/apoE(-/-) double-knockout mice confirming the specificity of Ang-(1-7) action through the Mas-receptor. In summary, Ang-(1-7) modulates vascular function via Mas-receptor activation that attenuates pressor response to Ang II in apoE(-/-) mice by reducing reactive oxygen species-mediated p38 mitogen-activated protein kinase activity.