Background: Severe mitral regurgitation (MR) after aortic valve replacement (AVR) is a serious complication. Although several causes of MR after AVR have been reported, severe MR due to geometric changes in the mitral valve imposed by an aortic valve prosthesis has not been reported. We here report a case of severe MR after AVR that was improved after re-AVR. Case presentation: A 77-year-old male underwent elective total aortic arch replacement and AVR. Mild MR was preoperatively identified. After surgery and separation from cardiopulmonary bypass, transesophageal echocardiography (TEE) demonstrated restriction and distortion of the anterior mitral leaflet and severe MR. Displacement of the anterior mitral annulus by the prosthetic aortic valve was strongly suspected to be the cause of MR, which should be surgically restored. Re-AVR using a small-sized valve was then performed. Consequently, the structural changes in the mitral valve were reverted and the MR was reduced. Conclusions: Geometric changes in the mitral valve induced by an aortic valve prosthesis can cause massive increment of MR. Intraoperative TEE examination of the mitral apparatus is important when severe MR occurs after AVR.
BACKGROUND:
Ipsilateral shoulder pain (ISP) is a common problem after pulmonary surgery. We hypothesized that phrenic nerve block (PNB) at the azygos vein level, near the location of the surgical operation, would be effective for reducing ISP. Our primary aim was to assess the effect of PNB on postoperative ISP, following video-assisted thoracic surgery (VATS).
METHODS:
This prospective, randomized, patient-blinded, single-institution trial was registered at the University Hospital Medical Information Network (UMIN000030464). Enrolled patients had been scheduled for VATS under general anesthesia with epidural analgesia. Patients were randomly allocated to receive infiltration of the ipsilateral phrenic nerve at the azygos vein level with either 10 mL of 0.375% ropivacaine (PNB group) or 0.9% saline (control group) before chest closure. Postoperative ISP was assessed using a numerical rating scale (NRS, 0–10) at rest at 2, 4, 8, 16, and 24 hours. The incidence of ISP was defined as the proportion of patients who reported an NRS score of ≥1 at least once within 24 hours after surgery. In the primary analysis, the proportion of patients with ISP was compared between PNB and control groups using the χ
2
test. NRS values of ISP and postoperative incision pain within 24 hours were investigated, as was the frequency of postoperative analgesic use. Incision pain was assessed using an NRS at the time of ISP assessment. Finally, the incidence of postoperative nausea and vomiting and shoulder movement disorders were also evaluated.
RESULTS:
Eighty-five patients were included, and their data were analyzed. These patients were randomly assigned to either PNB group (n = 42) or control group (n = 43). There were no clinically relevant differences in demographic and surgical profiles between the groups. There was no significant difference in the incidence of ISP (the control group 20/43 [46.5%] versus the PNB group 14/42 [33.3%];
P
= .215). The severity of ISP was lower in the PNB group than in the control group (linear mixed-effects model, the main effect of treatment [groups]:
P
< .001). There were no significant differences between groups in terms of postoperative incision pain. The frequency of postoperative analgesic use was significantly higher in the control group (Wilcoxon rank sum test,
P
< .001). Postoperative nausea and vomiting did not significantly differ between the 2 groups. There were no changes in the range of shoulder joint movement.
CONCLUSIONS:
Azygos vein level PNB did not significantly affect the incidence of ISP after VATS.
The frequency response of transfer coefficient to flow-rate change in laminar tube flow is studied experimentally and analytically.In the analysis, the linearized basic equation is solved both numerically and by using a similarity variable which is used in analysis of steady-state problem. In the experiment, the variations of local value and space-averaged value with respect to time are measured under two heating conditions, i.e., constant wall heat-flux and constant wall temperature. From these results it is concluded that the similarity relation is not preserved in unsteady state and that resonance occurs in variation of transfer coefficient. This resonance point is characterized by a parameter SnPrX2/s which is derived from a similarity relation. In the last part of this paper, the effect of pulsating flow on the time-averaged transfer coefficient is discussed.
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