| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Ann Thorac Surg 2000;70:1763
© 2000 The Society of Thoracic Surgeons
a Norton Audubon Hospital, One Audubon Plaza Drive, Louisville, KY 40217, USA,
e-mail: tracy.trumbo{at}nortonhealthcare.org
To the Editor
I enjoyed the recent concise and balanced review article by Dr Bridges [1]. I would like to add some new personal observations about this topic. In the last 6 years, I have performed over 500 transmyocardial laser revascularization (TMR) procedures using two different lasers. The difference in results between the two energy sources has been previously described [2]. With the carbon dioxide laser, there was progressive improvement in both angina relief and perfusion by thallium scan continuing up to 1 year, so that at 1 year, 40% of the patients had no angina. With the Holmium-YAG, there was improvement up to 3 months, but none thereafter, and at 1 year, 40% of the patients were still class II. It appeared that different lasers had different effects on the ischemic myocardial tissue.
Of particular interest was 1 patient in whom none of the CO2 laser shots reached the ventricular cavity because of a very fatty epicardium, so a reptillian circulation could not be established [2]. However, 1 year postoperatively, he was angina class I and the perfusion was markedly improved by persantine-thallium study. Therefore, about 18 months ago, we began to wonder if release of vascular endothelial growth factor (VEGF) by the CO2 laser could explain this effect and began to measure VEGF levels in the peripheral blood postoperatively by a standard ELISA method (R&D Systems, Inc, Minneapolis, MN). In 23 patients, there was a steady rise in the blood level, so that at 7 days it had increased by an average of 400%. Statistical analysis using a paired t test, comparing base line to 7 days, had a value of p < 0.0002. This was maintained up to 15 days, but after 1 week, we had too few patients to analyze values statistically. The rise might have been caused by the thoracotomy incision, but other investigators injecting VEGF directly into the heart muscle by thoracotomy did not observe a postoperative increase in the peripheral blood [3, 4]. Thus, the VEGF measured in the blood in our patients after TMR is not caused by the thoracotomy, but is released as a result of the laser effect on the myocardium. This dose must be much greater than that administered in the direct injections. Despite this, we have seen no retinopathy or tumors in up to 6 years of follow-up.
Once again, I enjoyed this overview and commend Dr Bridges on his clear and comprehensive presentation.
Footnotes
Dr Lansing participates in training new teams in TMR surgery for both PLC Medical Systems and Eclipse Surgical Technology Inc, for which he receives small stipends. Neither company supported this work.
References
Related Article
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
