Validation of a new transit time ultrasound flowmeter in man

Laustsen, Jesper; Pedersen, Erik Morre; Terp, Kim; Steinbrüchel, Daniel A.; Kure, H. H.; Paulsen, Peter Kildeberg; Jørgensen, Hanne Skou; Paaske, William P.

doi:10.1016/s1078-5884(96)80282-6

Cited by 103 publications

(69 citation statements)

References 7 publications

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“…1 Transit time flowmetry seems to be an adequate and reliable tool in evaluating adequate intraoperative graft flow. 2,3 It gives the surgeon three different parameters which collectively can indicate abnormal flow in graft. A pulsatility index greater than 6 and a peaked systolic rather than a diastolic flow curve coupled with a low flow clearly indicate an abnormal graft flow.…”

Section: Discussionmentioning

confidence: 99%

Retrograde Flow from the LAD into the LIMA with no Antegrade Flow Can Easily be Missed

Fouda

2002

Ann Saudi Med

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A 58-year-old anesthesia technician in our hospital was diagnosed as a case of triple-vessel coronary artery disease needing three grafts. He was taken to the operating room where a plan of grafting the LAD with a LIMA, a proximal and distal obtuse marginals with veins grafts was pursued. The LIMA flow was noticed to be sluggish after harvesting, and papaverin was injected into it with a moderately good response. A size 1 mm probe was then passed down the LIMA to release any proximal spasm. The flow increased dramatically after this manuever. The LIMA to LAD anastomosis was done using off-pump technique, which is practiced in more than 90% of CABGs in our center. After the completion of anastomosis, a transit time flowmetry probe was used to measure the flow in the graft, unfortunately, the flow was 0 mL/min with abnormal systolic peak in the flow curve and a pulsatility index of more than 30. Pulsatility index should not be more than 6 if there is a reasonable antigrade flow in the graft.Accordingly, a decision was made to open the graft through a proximal branch and then to pass a probe to check the anastomosis. Once the artery was opened, a huge flow of blood was observed, and a size 2.0-mm probe was passed easily across the anastomosis. A bulldog was then put across the LIMA between the anastomosis and the open brranch, and to our surprise there was no antigrade flow at all. The artery was examined fully and a very proximal hematoma was observed around the artery. The LIMA was transected distal to the hematoma and anastomosed as a free graft to the ascending aorte. Transit time flowmetry was repeated with very good diastolic flow and wave pattern and with a pulsatility index of only 1.7 DiscussionEarly detection of inadequate LIMA flow to LAD is essential as we know the importance of this particular graft in short-and long-term prognosis of patients. Strong retrograde flow can obviously mimic adequate LIMA antigrade flow in some cases, giving a false palpable pulse in the LIMA after completion of anastomosis.ECG is obviously expected to be normal as long as there are no anastomosis problems and accordingly cannot be used to guarantee adequate mammary flow.1 Transit time flowmetry seems to be an adequate and reliable tool in evaluating adequate intraoperative graft flow.2,3 It gives the surgeon three different parameters which collectively can indicate abnormal flow in graft. A pulsatility index greater than 6 and a peaked systolic rather than a diastolic flow curve coupled with a low flow clearly indicate an abnormal graft flow. 4,5 Unfortunately, and in a case such as ours, the absence of such a diagnostic facility means that the patient would have to come back within a short period with early recurrent angina. We have revised five grafts over the last two years for different technical error, and they were all detected using the transmit time flowmetry. We strongly recommend the use of this technique in all CABG cases, especially those which are done using the off-pump technique. Mohammed Fouda, MD

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Section: Discussionmentioning

confidence: 99%

Retrograde Flow from the LAD into the LIMA with no Antegrade Flow Can Easily be Missed

Fouda

2002

Ann Saudi Med

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“…Intraoperative transit time flow (TTF) and vascular resistance were measured with a CardioMed flow meter (CM-4008, Medi-Stim, AS, Oslo, Norway) using 3 and 4 mm probes [6,[8][9][10]. The transit time method is based on the fact that the time required for ultrasound to pass through blood is slightly longer upstream than downstream.…”

Section: Flow Measurement With the Transit Time Methodsmentioning

confidence: 99%

Failed coronary artery bypass anastomosis detected by intraoperative coronary flow measurement

Walpoth

Bosshard

Kipfer

et al. 1998

European Journal of Cardio-Thoracic Surgery

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Objectives: To assess intraoperative flow of arterial and venous coronary grafts after myocardial revascularization which may allow early detection of low flow situations, especially during minimally invasive coronary bypass surgery (MIDCAB), and lead to immediate correction of technical problems. Methods: In two patients with severe and diffuse multi-vessel disease the left internal mammary artery (IMA) was connected to the left anterior descending artery (LAD). During reperfusion, the flow was measured in the IMA and vein grafts using a transit time flow meter. Results: In both cases the IMA showed only a systolic pendulating flow curve with a mean flow of 0-1 ml/ min and a high resistance. Manual IMA assessment revealed an adequate pulsation. Both distal IMA anastomoses were re-explored on cardiopulmonary bypass yielding an initial flow of 7 and 14 ml/min, respectively. After treatment with papaverine/adenosine the IMA flow increased from 7 to 26 ml/min (coronary flow reserve (CFR) = 3.7) and from 14 to 46 ml/min (CFR = 3.3), respectively. Conclusion: Intraoperative flow assessment of IMA and venous bypass grafts can be recommended to monitor flow; especially during MIDCAB procedures.

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“…The usefulness of this method for evaluation of coronary graft fl ow in cardiovascular surgery has been reported by several authors 1,2,3 . The greatest advantage of the TTFM is the ease with which a technical error is detected, i.e., anastomotic stenosis.…”

Section: Introductionmentioning

confidence: 90%

Cardiomed Coronary Flow Meter for Prevention of Early Occlusion in Aortocoronary Bypass Grafting

Gwozdziewicz¹

2004

BIOMED PAP

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Validation of a new transit time ultrasound flowmeter in man

Abstract: The transit time apparatus was simple to use during intraoperative settings and gave fast, precise measurements of volume blood flow.

Cited by 103 publications

References 7 publications

Retrograde Flow from the LAD into the LIMA with no Antegrade Flow Can Easily be Missed

Retrograde Flow from the LAD into the LIMA with no Antegrade Flow Can Easily be Missed

Failed coronary artery bypass anastomosis detected by intraoperative coronary flow measurement

Cardiomed Coronary Flow Meter for Prevention of Early Occlusion in Aortocoronary Bypass Grafting

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