Mechanical valve closing dynamics: Relationship between velocity of closing, pressure transients, and cavitation initiation

1997 ◽  
Vol 25 (6) ◽  
pp. 926-938 ◽  
Author(s):  
Krishnan Bala Chandran ◽  
Srinivas Aluri
Keyword(s):  
Mechanical Valve ◽  
Pressure Transients ◽  
Valve Closing Dynamics ◽  
Closing Pressure

Passing a Mechanical Aortic Valve With a Short Tip Dilator to Facilitate Aortic Arch Endovascular Branched Repair

2021 ◽  
pp. 152660282110025
Author(s):  
Nikolaos Konstantinou ◽  
Sven Peterss ◽  
Jan Stana ◽  
Barbara Rantner ◽  
Ramin Banafsche ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Arch ◽  
Stent Graft ◽  
Mechanical Valve ◽  
Valve Prosthesis ◽  
Proper Position ◽  
Mechanical Aortic Valve ◽  
Aortic Replacement ◽  
Custom Made ◽  
Aortic Valve Prosthesis

Purpose To present a novel technique to successfully cross a mechanical aortic valve prosthesis. Technique A 55-year-old female patient with genetically verified Marfan syndrome presented with a 5-cm anastomotic aneurysm of the proximal aortic arch after previous ascending aortic replacement due to a type A aortic dissection in 2007. The patient also underwent mechanical aortic valve replacement in 1991. A 3-stage hybrid repair was planned. The first 2 steps included debranching of the supra-aortic vessels. In the third procedure, a custom-made double branched endovascular stent-graft with a short 35-mm introducer tip was implanted. The mechanical valve was passed with the tip of the dilator on the lateral site of the leaflet, without destructing the valve and with only mild symptoms of aortic insufficiency, as one leaflet continued to work. This allowed the implantation of the stent-graft directly distally of the coronary arteries. Postoperative computed tomography angiography showed no endoleaks and patent coronary and supra-aortic vessels. Conclusion Passing a mechanical aortic valve prosthesis at the proper position is feasible and allows adequate endovascular treatment in complex arch anatomy. However, caution should be taken during positioning of the endovascular graft as the tip may potentially damage the valve prosthesis.

scholarly journals Post hoc patient satisfaction with the choice of valve prosthesis for aortic valve replacement: results of a single-centre survey

2021 ◽  
Author(s):  
Laure Bryssinck ◽  
Siel De Vlieger ◽  
Katrien François ◽  
Thierry Bové
Keyword(s):  
Patient Satisfaction ◽  
Aortic Valve ◽  
Confidence Interval ◽  
Aortic Valve Replacement ◽  
Valve Replacement ◽  
Odds Ratio ◽  
Mechanical Valve ◽  
Decisional Conflict ◽  
Valve Prosthesis ◽  
Post Hoc

Abstract OBJECTIVES Our goal was to examine post hoc patient satisfaction and the decision-making process of choosing a prosthesis for aortic valve replacement (AVR). METHODS We surveyed 113 patients who were operated on for AVR at 60–70 years of age, including 74 patients with a mechanical valve (MECH) and 39 with a bioprosthesis (BIO). The study focused on quality of life and the decision pathway in relation to prosthesis choice and valve-related complications. Decisional conflict was defined as the post hoc uncertainty perceived by patients regarding their choice of prosthesis. RESULTS The survey was performed at a median of 5.2 (3.2–8.1) years after the AVR. Patients with a biological valve were older (BIO: 68.4 years [66.2–69.4] vs MECH: 63.9 [61.9–66.7]; P < 0.001). Global post hoc satisfaction with prosthesis choice was high in both groups (MECH: 95.9%; BIO: 100%), and 85.1% (MECH) and 92.3% (BIO) of them would repeat their choice. Conflict about their decision was equal (MECH: 30.3%; BIO: 32.6%) for different reasons: MECH patients experienced more anticoagulation-related inconvenience (25.9% vs 0%), fear of bleeding (31.1% vs 0%) and prosthesis noise (26.2% vs 0%), whereas more BIO patients feared prosthesis failure (39.7% vs 17.4%) or reoperation (43.5% vs 18.1%). Active involvement in the decision (odds ratio 0.37, 95% confidence interval 0.16–0.85; P = 0.029) and adequate information about the prosthesis (odds ratio 0.34, 95% confidence interval 0.14–0.86; P = 0.020) decreased the risk of conflict about the decision. CONCLUSIONS Although 30% of the responders showed a decisional conflict related to prosthesis-specific interferences, global patient satisfaction with the prosthesis choice for AVR is excellent. Increasing the patient’s involvement in the prosthesis choice through shared accountability and improved information is recommended to decrease the choice-related uncertainty.

Lip‐closing pressure during food intake from a spoon in normal children

2021 ◽  
Author(s):  
Yuki Sasakawa ◽  
Yuki Nakamura ◽  
Issei Saitoh ◽  
Tsutomu Nakajima ◽  
Saeko Tsukuno ◽  
...  
Keyword(s):  
Food Intake ◽  
Normal Children ◽  
Closing Pressure

A square-pulse flow method for measuring characteristics of the arterial bed

1976 ◽  
Vol 40 (3) ◽  
pp. 425-433 ◽  
Author(s):  
M. G. Bottomley ◽  
G. W. Mainwood
Keyword(s):  
Arterial Compliance ◽  
Peripheral Resistance ◽  
Mean Value ◽  
Pressure Response ◽  
Arterial System ◽  
Response Curves ◽  
Arterial Tree ◽  
Pulse Flow ◽  
Critical Closing Pressure ◽  
Closing Pressure

A device was designed to provide a “square” pulse of blood flow into the arterial system. Pulses were injected into the carotid artery of the rabbit during transient cardiac arrest. Analysis of pressure response curves generated by the flow provides information as to the state of the arterial tree. With certain assumptions it is possible to estimate from these curves lumped values of peripheral resistance, critical closing pressure, and arterial compliance. In a series of 12 rabbits the mean value of peripheral resistance was found to be 0.21 +/- 0.7 mmHg-ml-1-min and critical closing pressure was estimated to be 23.6 +/- 3.8 mmHg. This method gives two possible values for arterial compliance 0.036 +/- 0.010 and 0.055 +/- 0.010 ml-mm-1 based, respectively, on the rise and decay curves of the pressure response. The theory and limitations of the method are discussed. The use of the method is illustrated in following the response to increased PCO2 and hemorrhage.

Outcome of Pulmonary Autograft After the Ross Procedure

2021 ◽  
Vol 12 (4) ◽  
pp. 508-515 ◽  
Author(s):  
Yuki Nakayama ◽  
Takeshi Shinkawa ◽  
Goki Matsumura ◽  
Ryogo Hoki ◽  
Kei Kobayashi ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Hospital Discharge ◽  
Mechanical Valve ◽  
Good Health ◽  
Hospital Death ◽  
Ross Procedure ◽  
Prosthetic Aortic Valve ◽  
Related Risk ◽  
Combined Lesions

Background: The purpose of this study was to assess autograft function after the Ross procedure and to review surgical outcomes associated with autograft reoperations. Methods: This is a retrospective study of patients undergoing the Ross procedure since 1993. Autograft function and autograft reoperation were studied. Autograft failure was defined as more than moderate autograft regurgitation or autograft dilatation to more than 50 mm diameter or z-score of more than +4 in children. One hospital death was excluded from analysis as were patients with unknown late autograft status. Results: Among 75 patients analyzed, preoperative diagnosis before the Ross procedure included aortic regurgitation in 26, aortic stenosis in 19, combined lesions in 28, and 2 mechanical valve malfunctions. Median age at the Ross procedure was 12.1 (0.4-43.6) years with 44 children less than 15 years old. Six patients had greater than mild autograft regurgitation at post-Ross hospital discharge. During median follow-up of 14.9 years, there were 23 autograft failures. Eighteen autograft reoperations were performed on 17 patients (13 children), including 12 aortic valve replacements, 5 aortic root replacements (including 1 valve-sparing root replacement), and 1 Konno procedure. Freedom from autograft failure and autograft reoperation at 20 years after the Ross procedure was 52.0% and 66.3%, respectively. Multivariate analysis identified greater than mild autograft regurgitation at hospital discharge from Ross procedure as a risk factor for autograft failure ( P < .01). All patients who underwent autograft reoperation survived and had good health status at a median of 6.9 years after the reoperation. Conclusions: The Ross procedure is effective in delaying prosthetic aortic valve replacement, although the time-related risk of autograft failure is a real consideration.

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