[HSF] help with flow probe

[erdinç naseri]

Don,
I do a patch angioplasty on the stenotic segments less than 60% with a piece of vein( and tie the proximal end).This way the problem of competitive flow is solved.This is possible for RCa  all the time but not so for CRX( some parts of the later are difficult to access)
erdinc> From: donross at bigpond.com> Subject: Re: [HSF] help with flow probe> Date: Sun, 27 May 2007 21:26:46 +1000> To: OpenHeart-L at lists.hsforum.com> CC: > > Bob,> I think you may actually be an expert!> You have answered all my questions and thrown up some other > interesting physiology.> Since I aim to use arterial grafts providing they are available and > veins for the odd prophylactic graft together with no aortic > clamping, the issue of competitive flow from the native is paramount.> I often leave 50% lesions to be stented if they cause problems later. > I would love to have the guts to partially clip them which would now > be possible with the aid of the probe.> I think I might be tempted to add to what looked like a 70% stenosis > and proved to be less when tested if I had already placed a lovely > arterial graft.> There is a can of worms for the ethicists and theoretical physiologists!> Thanks for your insights,> Don> On 27/05/2007, at 1:11 AM, McMani at aol.com wrote:> > > Don> > I'm not sure I'm an expert but I do have a lot of experience with > > routine flow probe measurements. The primary utility of the device > > is to avoid leaving the OR with a completely occluded graft. > > Unless an anastomotic stricture impedes flow by more than 70% it > > will not be detectable with the system. The next time you use it > > pinch the graft and see how different levels of occlusion affect > > the measurements. The "standard" levels of acceptability are > > overall flows of 10 cc/minute, pulsatility index (PI) of less than > > 5 and the volume of the diastolic flow curve. The most important > > numbers are the absolute flow and the diastolic curve. The PI is a > > calculated index derived by subtracting the minimum flow from the > > maximum flow and dividing by the mean flow. Grafts to the RV > > branches including the PDA can have high PI because there is better > > systolic flow into the RV branches in systole than into the LV > > branches. Formal measurements involve occluding the native > > coronary and the graft for several minutes in order to measure > > graft flow during maximal hyperemic response. then take the > > bulldog off the graft and measure flow. Then release the native > > coronary and re-measure, If the flow rises it is evidence that the > > heel is patent and that competitive flow is not an issue. If the > > flow falls it also proves that the heel is patent but suggests that > > the native coronary flow is reducing the graft flow. One is then > > left with the decision about whether to further limit the native > > flow or risk future "string sign". Another interesting area is > > when one places multiple grafts to a LIMA (Radial or RIMA > > extensions) with both flow limiting and non-flow limiting lesions > > grafted. Routine flow measurements have demonstrated disturbing > > reversals of flow in those circumstances which require judgement > > about whether to introduce a SVG into an all-arterial > > revascularization. I think it's better to know the flow but one is > > faced with new decisions with that data. If the flow is less than > > the parameters I described I usually probe the anastomosis by > > removing SVG side-branch clips and using a metal dilator. Since I > > use interrupted clips I can usually remove the heel or toe clips > > and replace them and remeasure flow. My goal is to document 100% > > anastomotic patency intra-operatively and carefully review the > > intra-operative flow characteristics in patients with subsequent > > documented anastomotic occlusions. The study has been going on for > > 7 years in 1200 patients and we're almost done. As you can tell I > > think flow measurement is important but other than alerting one to > > an inadvertent occlusion I'm not sure of the best way to use the data.> > Bob> > _______________________________________________> > OpenHeart-L mailing list> >> > Send postings to:> > OpenHeart-L at lists.hsforum.com> >> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> > http://mmp.cjp.com/mailman/listinfo/openheart-l> >> > All messages transmitted by the OpenHeart-L are subject to the > > policies and> > disclaimers posted at:> > http://www.hsforum.com/listdisclaim> > -----------------------------------------> _______________________________________________> OpenHeart-L mailing list> > Send postings to:> OpenHeart-L at lists.hsforum.com> > To UNSUBSCRIBE, to CHANGE email address, or to view archives:> http://mmp.cjp.com/mailman/listinfo/openheart-l> > All messages transmitted by the OpenHeart-L are subject to the policies and > disclaimers posted at:> http://www.hsforum.com/listdisclaim> -----------------------------------------