Transit-time flow measurement for detection of early graft failure during myocardial revascularization

doi:10.1016/S0003-4975(98)00653-5

The Annals of Thoracic Surgery

Volume 66, Issue 3, September 1998, Pages 1097-1100

Presented as a Poster at “Facts and Myths of Minimally Invasive Cardiac Surgery: Current Trends in Thoracic Surgery IV”, New Orleans, LA, Jan 24, 1998.

https://doi.org/10.1016/S0003-4975(98)00653-5 Get rights and content

Abstract

Background. A low-flow situation in arterial and venous grafts has been associated with high rates of perioperative infarction and mortality. This study was designed to look at intraoperative graft flow and resistance in patients with coronary artery disease.

Methods. Coronary artery bypass graft flow was measured in 46 patients. Transit-time flow was used for coronary flow measurements at rest as well as after maximal vasodilation with adenosine infusion.

Results. Forty-three of the 46 patients showed normal internal mammary artery graft flow (>20 mL/min); 3 patients had no or minimal graft flow. Redoing the graft anastomosis in these 3 patients resulted in normalization of graft flow. The mean flow increased significantly after correction from 0.5 ± 0.7 mL/min to 15.7 ± 9.6 mL/min (p < 0.02). Conversely, vascular resistance decreased significantly from 138 ± 10 to 4.8 ± 1.8 Ohmv (p < 0.0001), as did the pulsatility index (from 146.9 ± 95.7 to 3.4 ± 1.8; p < 0.001). After correction, coronary flow reserve was 2.5 ± 1.1.

Conclusions. Measurements of intraoperative flow and resistance as well as derived variables allow assessment of early graft function and thus help prevent graft failure and reduce perioperative infarction. Transit-time volume flow might be a simple tool for quality control in coronary bypass procedures.

Section snippets

Patients and methods

Forty-six patients underwent coronary artery bypass grafting using the left internal mammary artery (IMA). In our institution, intraoperative transit-time flow measurement is routinely performed in patients who are undergoing coronary artery bypass procedures and are at increased perioperative risk because of hemodynamic instability, severely reduced left ventricular function, or diffuse coronary artery disease. Our operative technique includes moderate hypothermic cardiopulmonary bypass (32°C)

Results

In 43 patients, flow through the IMA graft was normal (>20 mL/min). In 3 patients, a low-flow situation (mean flow, < 0.5 ± 0.7 mL/min) was found in the left IMA to the left anterior descending coronary artery. Calculated vascular resistance was significantly elevated (138 ± 10 Ohmv or mm Hg · mL⁻¹ · min⁻¹), pulsatility index was pathologically high (147 ± 96), diastolic backflow showed an insufficiency of more than 50%, and diastolic filling was absent (Table 1). The reason for the low-flow

Comment

Low coronary artery bypass flow is associated with early graft failure and high risk of perioperative myocardial infarction 18, 19. Thus, early recognition of low graft flow will alert the surgeon and avoid early graft occlusion. The purpose of the study was to evaluate the impact of transit-time flow and resistance measurements on graft function and patency in 46 patients with coronary artery disease undergoing coronary artery bypass grafting. In 43 patients, good functional reserve was

Acknowledgements

This work was supported in part by a grant from The Swiss Heart Foundation.

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Intraoperative TTFM is valuable for the assessment of the quality of established AVFs. Especially PI was correlated successful hemodialysis management for over 12 months, the recommended acceptable range was 0.43–0.77.
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Minimally Invasive Cardiac Surgery SupplementsTransit-time flow measurement for detection of early graft failure during myocardial revascularization

Abstract

Section snippets

Patients and methods

Results

Comment

Acknowledgements

J Thorac Cardiovasc Surg

Ann Thorac Surg

Ann Thorac Surg

Ann Thorac Surg

Ann Thorac Surg

Ann Thorac Surg

J Cardiothorac Vasc Anesth

Eur J Vasc Endovasc Surg

Ann Thorac Surg

Ann Thorac Surg

Minimally Invasive Cardiac Surgery Supplements
Transit-time flow measurement for detection of early graft failure during myocardial revascularization