Histologic appearance of transmyocardial laser Channels after 41/2 Weeks

Burkhoff, Daniel; Fisher, Peter; Apfelbaum, Mark; Kohmoto, Takushi; DeRosa, Carolyn; Smith, Craig R.

doi:10.1016/0003-4975(96)00090-2

Cited by 144 publications

(45 citation statements)

References 5 publications

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“…Human autopsy studies showed occluded channels as early as 2 days after surgery. 9,10 Few studies have shown an increase in myocardial perfusion after TMR. 12,22 Increased perfusion, when present, was not correlated with channel patency.…”

Section: Discussionmentioning

confidence: 99%

“…7,8 However, the majority of human and experimental studies have not been able to demonstrate histologically sustained patency of the channels created. 9,10 Objective improvement in myocardial perfusion by thallium imaging studies has also been an inconsistent finding. 5,[11][12][13] Furthermore, improvement in myocardial perfusion has been documented primarily several months after TMR, whereas the improvement in angina is observed in most patients within a few days after the procedure.…”

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confidence: 99%

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Cardiac Sympathetic Denervation After Transmyocardial Laser Revascularization

et al. 1999

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Background-Transmyocardial laser revascularization (TMR) has been shown to improve refractory angina not amenable to conventional coronary interventions. However, the mechanism of action remains controversial, because improved myocardial perfusion has not been consistently demonstrated. We hypothesized that TMR relieves angina by causing myocardial sympathetic denervation. Methods and Results-PET imaging of resting and stress myocardial perfusion with [13 N]ammonia (NH 3 ) and of sympathetic innervation with [11 C]hydroxyephedrine (HED) was performed before and after TMR in 8 patients with class IV angina ineligible for CABG or PTCA. A mean of 50Ϯ11 channels were created in the left ventricle (LV) with a holmium:YAG laser. A semiautomated program was used to determine NH 3 uptake and HED retention in the LV. Perfusion and innervation defects were defined as the percentage of LV with tracer uptake or retention Ͼ2 SD below normal mean values. All patients experienced improvement in their angina by 2.4Ϯ0.5 angina classes after surgery, Pϭ0.008. Sympathetic innervation defects exceeded resting perfusion defects in all patients before TMR (34.6Ϯ27.3% for HED versus 9.4Ϯ10.8% for NH 3 , Pϭ0.008). TMR did not significantly affect resting or stress myocardial perfusion but increased the extent of sympathetic denervation in 6 of 8 patients by 27.5Ϯ15.9%, Pϭ0.03. In the remaining 2 patients, both sympathetic denervation and stress perfusion defects decreased after surgery. Conclusions-TMR causes decreased myocardial HED uptake in most patients without significant change in resting or stress myocardial perfusion, suggesting that the improvement in angina may be at least in part due to sympathetic denervation. (Circulation. 1999;100:135-140.)

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Section: Discussionmentioning

confidence: 99%

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Cardiac Sympathetic Denervation After Transmyocardial Laser Revascularization

et al. 1999

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“…Most experimental 5 6 as well as clinical studies [7][8][9] have failed to establish the long term patency of laser channels. Two other mechanisms have emerged as valid alternatives for the explanation of the clinical improvement: nerve destruction 17 and neovascularisation.…”

Section: Discussionmentioning

confidence: 99%

“…However, channel patency has been seriously questioned by experimental 5 6 as well as clinical data. [7][8][9] Neovascularisation induced by the laser has been suggested as a potential mechanism. Because of its potential for percutaneous application, the holmium:yttrium-aluminium garnet (holmium-YAG) laser has emerged as a promising device for laser revascularisation.…”

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Sudden death following occlusion of the left coronary artery by a large stalky excrescense

Abrahamsen¹,

Kristensen²,

Baandrup³

2001

Heart

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Aim-To analyse the arteriolar pattern of laser induced channels and their surroundings compared with mechanical and ischaemic injury. Methods-24 pigs were randomised to a myocardial infarction group, a transmyocardial laser revascularisation group, a needle group, or a control group. In the laser revascularisation and needle groups, five channels were created either with a 1.75 mm probe holmium-YAG laser or a Tru-cut needle of the same size. Animals were killed 28 days later. ; p = 0.6 and p = 0.4, respectively). The mean arteriolar diameter was similar throughout all the regions analysed. Conclusions-Both laser and needle channels produce a similar increase in arteriolar structures, which is limited to the lesion itself. This suggests that laser injury is not more potent as an angiogenic stimulator than mechanical injury, which in turn is superior to infarction. (Heart 2001;85:697-701)

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“…However, many aspects still remain unclear, such as the role of new channels [6]or mechanisms of improvement with respect to clinical status or contractile reserve [7]. Since the initial reports on experiments by Mirhoseini and Cayton [3], and the clinical success obtained in preliminary studies [4], this therapy remains controversial, although clinical improvement seems to be achieved by a great proportion of patients (table 5).…”

Section: Discussionmentioning

confidence: 99%

Transmyocardial Revascularization with Holmium Laser

Garcia-Rubira

et al. 1998

Cardiology

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Sixteen patients with angina refractory to medical therapy who were not considered suitable for standard revascularization underwent transmyocardial revascularization with holmium laser. The average age of the patients was 63.2 ± 10.5 years. All of them had angina class 3 or 4, and 9 (56%) had previously undergone an aortocoronary bypass grafting. Four patients died during the 6-month follow-up period (25%). Among the survivors, anginal class decreased to class 2 or 1 at the 6th month (p = 0.002). Ejection fraction did not change. The ischemic burden by Holter decreased from 85.3 ± 656 to 5.5 ± 9.7 min (p = 0.046). Myocardial perfusion with ²⁰¹Tl single photon emission computed tomography (SPECT) images at rest and after dipyridamole showed a significant improvement among the ischemic treated segments (p = 0.015). Baseline ejection fraction was somehow lower in nonresponsive than in responsive patients (33 ± 13 vs. 49 ± 10, p = 0.052). We conclude that transmyocardial laser revascularization with holmium laser is effective in treatment in ischemic patients not amenable to surgery or percutaneous procedures, as previously reported with CO₂ laser. Further investigation is needed to determine which clinical profiles identify the patients for whom this therapy is suitable.

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Histologic appearance of transmyocardial laser Channels after 41/2 Weeks

Cited by 144 publications

References 5 publications

Cardiac Sympathetic Denervation After Transmyocardial Laser Revascularization

Cardiac Sympathetic Denervation After Transmyocardial Laser Revascularization

Sudden death following occlusion of the left coronary artery by a large stalky excrescense

Transmyocardial Revascularization with Holmium Laser

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