Transapical Delivery System with Ventriculoarterial Bypass
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Solution Overview
Problem
Minimally invasive aortic valve replacement procedures using transapical approaches face complications such as reduced cardiac output, increased left ventricular afterload, and device embolism due to obstruction and forceful deployment of crimped stented valve prostheses during deployment on a beating heart.
Innovation Solution
A delivery system with a trocar tube configured to create a ventriculoarterial bypass, allowing blood to bypass the aortic valve by directing flow from the left ventricle to downstream arteries, thereby maintaining cardiac output and reducing contractile resistance, using a trocar tube with holes for blood drainage and bypass tubes to extracardiac arterial sites, and optionally employing a self-expanding or balloon-expandable prosthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crimped stented valve prosthesis is advanced to the aortic orifice for deployment, then the valve replacement procedure can be performed, but cardiac output is reduced due to obstruction of the native valve's orifice
Solution Approach 1:
A bypass tube is introduced as an intermediary element to create an alternative blood flow pathway from the left ventricle to the aorta, bypassing the obstructed aortic orifice where the crimped valve prosthesis is positioned. This mediator allows blood to flow around the obstruction, maintaining cardiac output while enabling valve deployment.
Solution Approach 2:
The blood flow pathway is segmented into two separate routes: the normal path through the aortic valve (which is obstructed) and an alternative path through the bypass tube. This segmentation allows one pathway to be blocked for procedural purposes while the other maintains physiological function.
2Reliability
If a crimped stented valve prosthesis is positioned at the aortic orifice, then valve implantation is achieved, but left ventricular afterload increases substantially which may result in pump failure
Solution Approach 1:
The bypass tube serves as a mediator that diverts blood flow away from the obstructed aortic orifice, reducing the afterload burden on the left ventricle. By providing an alternative low-resistance pathway, the bypass tube prevents excessive pressure buildup that would otherwise occur against the crimped valve.
3Manufacturing precision
If forceful left ventricular contraction occurs against the valve prosthesis during deployment, then the prosthesis can be expanded, but device embolism or migration occurs
Solution Approach 1:
The bypass tube acts as a pressure relief mediator during prosthesis deployment. By providing an alternative flow path, it prevents excessive pressure buildup during left ventricular contraction against the crimped valve, thereby reducing the risk of forceful jet effects that could cause device embolism or migration while still allowing controlled expansion.
4Reliability
If rapid right ventricular pacing is used to induce transient hemodynamic cardiac arrest, then afterload increase and device migration risk are reduced, but cardiac output drops which may be poorly tolerated by patients
Solution Approach 1:
The bypass tube serves as a physiological mediator that maintains cardiac output during valve deployment without requiring hemodynamic manipulation techniques like rapid pacing. It provides a passive mechanical solution that preserves normal blood flow while creating the safe conditions normally achieved through active physiological intervention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system maintains normal cardiac output and reduces the risk of left ventricular failure and device migration by establishing a bypass pathway, allowing for safe and effective deployment of the prosthetic valve without causing excessive obstruction or embolism.
Implementation Method 1
allowing blood to bypass the aortic valve by directing flow from the left ventricle to downstream arteries
Data Source
AI summary
Apparatus is provided for implanting a prosthetic device (108) in a patient, the apparatus includes a trocar tube (101), a first portion of which is configured to be placed in a left ventricle (12) of the patient during a procedure for implantation of the prosthetic device (108), and a second portion of which is configured to be placed in an extracardiac location during the procedure. The first portion is shaped so as to define at least one opening to an interior thereof. One or more flexible bypass tubes (103, 104, 106), each of which is coupled to the second portion, and each of which is configured to be coupled to at least one artery (20, 21, 30) of the patient, so as to create a blood flow bypass path during the procedure, from the left ventricle (12), via the opening and the bypass tubes (103, 105, 106), to the at least one artery (20, 21, 30). Other embodiments are also described.