Measurement of Myocardial Blood Flow With Positron Emission Tomography Before and After Transmyocardial Laser Revascularization

Rimoldi, O.; Burns, Sharon M; Rosen, S. D.; Wistow, T. E.; Schofield, Peter M.; Taylor, G.; Camici, P. G.

doi:10.1161/01.cir.100.suppl_2.ii-134

Cited by 26 publications

(10 citation statements)

References 24 publications

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“…However, some groups were able to demonstrate in animal experiments some increase in myocardial perfusion by means of positron emission tomography, as well as contractile reserve by means of dobutamine stress echocardiography 6 months after TMLR [26,35]. Our own observations support the hypothesis of neoangiogenesis, with the help of an immunohistochemical stain (av- idin, biotin, peroxidase) by which we could demonstrate a 200-300% increase in the vascular endothelial cell density around laser channels ( fig.…”

Section: Experimental Studies and Potential Mechanisms Of The Laser Esupporting

confidence: 69%

Transmyocardial Laser Revascularization: Established Procedure, Acupuncture of the Heart or Placebo Effect?

Eckstein¹,

Boss²,

Frenz

et al. 2001

Heart Drug

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Considering the nearly universal skepticism transmyocardial laser revascularization (TMLR) aroused a few years ago, the so-called snake heart procedure has come a long way. The notion that the human heart enjoys significant perfusion from a spongy underlay of microcapillaries and sinusoids has been embraced by hundreds of researchers who have poked away at the coronary bed with external and internal lasers, radiofrequency probes, rotary cutters and saline jets, as well as developing technologies for implanting angiogenic growth factors into and around the resultant channels. TMLR has been described as a therapeutic option for end-stage coronary artery disease when percutaneous transluminal angioplasty and surgical myocardial revascularization are no longer possible and transplantation is not indicated. While debate continues to rage among surgeons and interventionists over the best way to perform transmyocardial laser, a greater question looms over the field: how does it work? No one has been able to explain yet why the procedure works in some patients and utterly fails in others, or to convincingly substantiate the procedure’s contributions to myocardial reperfusion. A few investigators believe that the procedure’s secret lies in creating patent channels. However, mid- and long-term patency of laser-created channels seem not to be required for successful treatment as initially assumed. The development of new vessels within and around the scar following TMLR (a phenomenon called ‘neoangiogenesis’) has moved more and more to the center of attention during the last few years. Some form of angiogenesis or neovascularization around the channels is the most favored explanation now, but nobody knows how TMLR stimulates such processes or how to measure them effectively. Although prospective randomized studies have been able to demonstrate some effectiveness of this treatment, the exact mechanisms of laser revascularization are still not completely elucidated. The notion of mechanisms such as sympathetic myocardial denervation and induction of microinfarctions transforming ischemia into necrotic myocardium has been abandoned. As recently as 1996, the prospect of transmyocardial revascularization becoming a breakthrough therapy seemed exciting enough to the financial market that the stock of PLC Medical Systems, then the front-runner in the field, soared to USD 32 per share. But in only the 2nd year since receiving FDA approval, the company is now trading at around USD 1.5 a share and the laser sales have fallen below expectations. One problem may be that many hospitals do not switch on their TMLR lasers very often once they are installed, with usage estimates as low as one or two procedures per month in some centers.

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Section: Experimental Studies and Potential Mechanisms Of The Laser Esupporting

confidence: 69%

Transmyocardial Laser Revascularization: Established Procedure, Acupuncture of the Heart or Placebo Effect?

Eckstein¹,

Boss²,

Frenz

et al. 2001

Heart Drug

View full text Add to dashboard Cite

show abstract

“…Previous studies with thallium perfusion and positron emission tomography (PET) have consistently shown improved overall perfusion, but they could not assess endocardial perfusion with the direct accuracy of cardiac MRI. [Frazier 1995;Allen 1999;Rimoldi 1999;Schofield 1999].…”

Section: Discussionmentioning

confidence: 99%

Use of Magnetic Resonance Imaging to Assess Myocardial Perfusion after Transmyocardial Laser Revascularization

Akay¹,

Cheong²,

Frazier³

2009

The Heart Surgery Forum

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“…In these reports, TMR was shown to significantly relieve angina, improve quality of life, increase exercise tolerance, and reduce hospital admissions [197][198][199][200][201]. However, two uncontrolled studies found no increase in regional blood flow on positron emission tomography [202,203] and reduction in angina may therefore result from either myocardial denervation or the placebo effect of thoracotomy [204,205]. The Society for Thoracic Surgeons has reported the recommendations for TMR as the sole therapy and as an adjunct to CABG [206].…”

Section: Transmyocardial Laser Revascularizationmentioning

confidence: 99%

Therapeutic angiogenesis for myocardial ischemia revisited: basic biological concepts and focus on latest clinical trials

et al. 2011

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Therapeutic angiogenesis is based on the premise that the development of new blood vessels can be augmented by exogenous administration of the appropriate growth factors. Over the last years, successful preclinical studies and promising results of early clinical trials have created great excitement about the potential of therapeutic angiogenesis for patients with advanced ischemic heart disease. The authors provide an overview of the biology of angiogenesis, the basic characteristics of angiogenic factors, and the different routes of their delivery. They discuss experimental studies in animal models of myocardial ischemia and outline available clinical studies on therapeutic angiogenesis for myocardial ischemia. Related safety issues are also addressed followed by a critical perspective about the future of proangiogenic therapies for ischemic cardiovascular disorders. Despite the established proof of concept and reasonable safety, however, results of the latest trials on therapeutic angiogenesis for myocardial ischemia have provided inconsistent results and the definite means of inducing clinically useful therapeutic angiogenesis remain elusive. More studies are required to gain further insights into the biology of angiogenesis and address pharmacological limitations of current approaches of angiogenic therapy. The authors hope and envisage that in the not-too-distant future, these investigative efforts will lead to important new strategies for treatment of myocardial ischemic syndromes. Means of non-invasive individualized pharmacological therapeutic neovascularization may be the next major advance in the treatment of ischaemic heart disease.

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Measurement of Myocardial Blood Flow With Positron Emission Tomography Before and After Transmyocardial Laser Revascularization

Cited by 26 publications

References 24 publications

Transmyocardial Laser Revascularization: Established Procedure, Acupuncture of the Heart or Placebo Effect?

Transmyocardial Laser Revascularization: Established Procedure, Acupuncture of the Heart or Placebo Effect?

Use of Magnetic Resonance Imaging to Assess Myocardial Perfusion after Transmyocardial Laser Revascularization

Therapeutic angiogenesis for myocardial ischemia revisited: basic biological concepts and focus on latest clinical trials

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