Histological Findings After Transmyocardial Laser Revascularization

Abstract

In recent time, it has become more and more probable that patients with severe diffuse coronary artery disease, who are not candidates for aortocoronary bypass surgery or percutaneous transluminal coronary angioplasty procedures, can benefit from transmyocardial laser revascularization (TMR). But the underlying principle of TMR still remains unclear. This study reports on a histological analysis of eight patients, in whom a total of 250 channels had been created, who died after TMR. The TMR channels were created by a C02 laser surrounded by a zone of necrosis with an extent of about 500 Fm. In the hearts of patients who died in the early postoperative period (1 to 7 days postoperative), almost all channels were closed by fibrin clots, erythrocytes, and macrophages. There were no obvious connections between the channels and the ventricular cavity. In specimens from patients, who died 2 or more weeks after the procedure, a granular tissue with high macrophage and monocyte activity was observable. Within this tissue, we observed a developing network of capillaries. Otherwise, the tissue filling the channels did not substantially differ from scar tissue. We failed to observe connections between the ventricular cavity and the new capillaries. Whether these vessels within the closed channels have any impact on myocardial perfusion remains unclear, but it seems unlikely that the clinical effects of TMR are based on the principle of the amphibian heart. (J Card Surg 1996;11:326-331) There are patients with coronary artery disease, who despite severe angina and significantly restricted quality of life cannot be treated by percutaneous transluminal coronary angioplasty (PTCA) or aortocoronary bypass operation. This concerns patients with diffuse sclerosis of the coronary arteries, as well as those with very small coronaries (small vessel disease). Currently, these patients were more and more treated by transmyocardial laser revascularization (TMR).During a TMR procedure, the surgeon drills

Histological Evidence of Angiogenesis 9 Months After Transmyocardial Laser Revascularization

“…[1][2][3] This is also the first time that red blood cells have been visualized in these neovessels. From the…”

Myocardial Angiogenesis Resulting in Functional Communications with the Left Cavity Induced by Intramyocardial High-Frequency Ablation: Histomorphology of Immediate and Long-Term Effects in Pigs

“…Laser energy is most widely used to create trans-/intramyocardial channels during direct myocardial revascularization [3]. Most of these channels become occluded by scar tissue within the 1st month as documented in clinical and animal investigations [4, 5]. We have demonstrated that transmyocardial channels can also be created by transmural insertions of an ablation electrode followed by high-frequency (HF) energy delivery [6].…”

Mechanisms and Results of Transmyocardial Laser Revascularization

“…Clinical work demonstrated some evidence of long-term patency [39, 40]. Additional experimental work showed some evidence of patency as well [41, 42, 43, 44]. There are also significant reports from autopsy series and laboratories that indicate that the channels do not remain patent [45, 46, 47, 48, 49].…”