[Indications for transmyocardial laser therapy]

In symptomatic endstage coronary artery disease after full medical therapy (antianginal drugs, betablockers and ACE-inhibitors) further therapeutical options both for the interventional cardiologist with little hope for improvement by PTCA, stent, rotablation and atherectomy and for the cardiac surgeon with bypass surgery and endarterectomy are not available by definition due to the diffuse arteriosclerotic vessel morphology. In those patients one can therefore consider transmyocardial laser therapy (TMR) as the ultimate treatment option. It then is primarily a palliative measure to reduce the patient's symptoms. Improving perfusion and prognosis remains the most important goals, however. TMR can be utilized as the only revascularizing treatment measure or in combination with CABG or PTCA. According to data from international registries, few controlled and several non controlled studies and our own registry in Marburg with now 101 patients improvement of angina and/or dyspnoea can be expected in more than 60% of patients with end stage coronary artery disease (CAD). The patient cohort comprises symptomatic individuals after CABG or multiple PTCAs or with diffuse CAD in diabetes mellitus or with most severe hypercholesterinemia. We consider these above mentioned criteria as the only validated criteria to enter patients with endstage CAD in our controlled study. Hypothetical options for treatment by TMR such as vasculopathies after heart transplantation, cardiomyopathies under the notion of a possible but not proven microangiopathy are not accepted in our institution at present. Before TMR all patients are assessed for their angina class according to the Canadian Cardiac Society (CCS I-IV)) and their exercise capacity according to the New York Heart Association classification (NYHA I-IV) and reassessed regularly after 3, 6 and 12 months. Thallium/Te MIBI scans at rest- and whenever possible at exercise as well as stress echocardiography are carried in the patients to assess symptomatic improvement, alterations in myocardial perfusion and functional efficacy by TMR. By intermediate analysis the 101 patients of our registry more than 60% of the patients had improved their angina class by at least one classe, some patients have improved perfusion as assessed by scintigraphy, which makes at present a trend but not yet a significant difference, whereas central hemodynamics and ejection fraction remained virtually unchanged in most patients reassessed after TMR. In our analysis mortality of the 101 TMR patients was assessed and plotted on Kaplan Meier survival curves. Mortality at 6 months was 11%. When compared to a historical group of patients with identical CCS and comparable NYHA classes, who were worked up in the manner of a case control study, the TMR mortality was marginally but not yet significantly lower than one would expect from these control patients with terminal CAD treated purely by medication: Their 6 months mortality was 14%. Remarkably but not unexpectedly patients with comparable CCS classes, who could still be treated by PTCA and/or CABG had a significantly lower 6 months mortality than TMR patients or patients on antianginal drugs only. The pathophysiological mechanisms for the symptomatic improvement by laser therapy are not yet fully understood. The 1 mm transmyocardial channels created by the CO2 laser have been postulated to permit perfusion from the ventricular cavity and to seek connection to capillaries and vessels present in the malperfused myocardium thus improving the perfusion by newly created connections and sinusoids from the ventricular cavity. Although there is clear evidence for the presence of open channels acutely and within a few days after TMR therapy little evidence in man is as yet available on the question whether the channels remain open in the long run and, if so, whether they can actually improve perfusion to a substantial degree...