Giovanni Paterni

Early Results of Transmyocardial Revascularization With a Holmium Laser

BACKGROUND Transmyocardial laser revascularization (TMLR), a surgical technique designed to improve perfusion in the ischemic myocardium by creating transmural channels, has been performed thus far using a carbon dioxide laser, with apparently gratifying early results. We have investigated clinically TMLR using a holmium laser as sole therapy for patients with coronary artery disease that is not amenable to traditional treatment such as coronary artery bypass grafting or percutaneous transluminal coronary angioplasty. METHODS From November 1995 to December 1996, 16 patients underwent TMLR using a holmium laser. Their mean age was 68 +/- 6 years and 75% were men. Previous coronary artery bypass grafting or percutaneous transluminal coronary angioplasty had been performed in 81% and 31% of the patients, respectively. Before operation, their mean anginal class was 3.4 +/- 0.5 and their mean left ventricular ejection fraction was 0.49 +/- 0.06. Six patients had unstable angina. RESULTS There were no operative deaths. The mean duration of TMLR was 27 +/- 13 minutes and the mean duration of the entire operation was 120 +/- 40 minutes. There were no major postoperative complications and the mean hospital stay was 8 +/- 4 days. There were 2 late deaths, 1 that occurred 40 days after TMLR as a result of stroke and 1 that occurred 4 months after TMLR as a result of myocardial infarction. Current survivors have been followed up for a mean of 10 +/- 4 months (range, 3 to 15 months), with 7 patients followed up for 1 year. At last follow-up, the mean anginal class had decreased to 1.8 +/- 0.7 (p = 0.001) and the patients had increased exercise tolerance and a reduced number of hospitalizations. However, no statistically significant changes in the percentage of segments with fixed or reversible ischemia and no statistically significant differences in the viability scores of lased and nonlased segments were observed. CONCLUSIONS Transmyocardial laser revascularization using a holmium laser is a simple technique with low operative risk and low morbidity. Early results confirm that clinical improvement is obtained in most patients, although significant changes in myocardial perfusion are not evident in the short term.

The impact of coronary artery disease on the coronary vasomotor response to nonionic contrast media.

BACKGROUND Coronary artery disease (CAD) alters the vasomotor response to a variety of pharmacological agents. We tested the hypothesis that CAD also has an impact on the coronary vasomotor response to radiologic contrast media. METHODS AND RESULTS We performed quantitative coronary angiography in 42 patients without angiographic evidence of CAD and 38 patients with CAD in the left coronary artery. Angiographically smooth coronary segments (n=235) were analyzed for changes on luminal diameters and coronary venous oxygen saturation in response to 3 media: the nonionic dimer iodixanol, the nonionic monomer iopromide, and the ionic agent ioxaglate. In subjects without CAD, we assessed the effects of intracoronary administration of the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine and of the cyclooxygenase inhibitor indomethacin on such changes. Iodixanol induced coronary vasodilation in subjects without CAD (8.8+/-8.6%, P<0.001). Patients with CAD exhibited no significant diameter changes in segments >/=20 mm apart from a stenosis (4.7+/-9.4%, P=NS) and significant constriction in segments <20 mm from a stenosis (-3.8+/-4.6%, P<0. 05). Similar results were obtained with iopromide, but no changes were found with ioxaglate. All contrast media induced transient (<35 seconds) increases in coronary venous oxygen saturation in all subjects. Indomethacin, but not N(G)-monomethyl-L-arginine, blunted the vasodilating effect of iodixanol and iopromide (by 80% and 76%, respectively; P<0.001). CONCLUSIONS Nonionic contrast media induce a vasodilatory response in normal vessels not by a mechanism involving increased flow or endothelial nitric oxide synthesis, but rather by depending on preserved vascular cyclooxygenase activity. CAD changes normal epicardial vasodilatory response into vasoconstriction.

Endothelin-1 Release from Atherosclerotic Plaque After Percutaneous Transluminal Coronary Angioplasty in Stable Angina Pectoris and Single-Vessel Coronary Artery Disease

To assess the effects of percutaneous transluminal coronary angioplasty on endothelin-1 (ET-1) release, we assessed ET-1 concentrations at different sites of the coronary circulation in patients submitted to elective procedures. ET-1 levels immediately downstream from the plaque and ET-1 aortocoronary gradient increased significantly after the procedure, which was related to mechanical wall stress in patients only receiving balloons, but not in those undergoing stent percutaneous transluminal coronary angioplasty. No changes were found in the coronary sinus; these results suggest ET-1 release from the plaque rather than an ischemia/reperfusion-related production from the distal myocardium.