First experience with hybrid percutaneous transmyocardial laser revascularization and angioplasty in patients with lesions at high risk for restenosis: Results of a phase I feasibility study.

BACKGROUND: Prior studies have suggested that percutaneous transmyocardial laser revascularization (PTMR) may be effective as a sole treatment modality in reducing angina in patients with severe coronary artery disease and no revascularization alternatives. The safety and efficacy of the hybrid or adjunctive use of PTMR during the same procedure as percutaneous intervention (PCI) has not previously been reported. METHODS: A US phase I feasibility study was therefore performed to determine whether PTMR performed in the same myocardial territory as PCI is able to ameliorate symptomatic recurrence from restenosis. RESULTS: After successful and uncomplicated PCI in 26 patients with class III-IV angina and lesion(s) at high risk for restenosis, PTMR was performed in the same myocardial territories subtended by the treated vessel(s). Major periprocedural adverse events (death, Q-wave myocardial infarction, and bypass surgery) occurred in 3 (11.5%) patients, as the result of subacute vessel closure in 2 patients, and tamponade in the third. Cumulative 6-month mortality rate was 19.2%, including 2 late deaths between 3 and 4 months after discharge (1 death caused by late stent closure and 1 unexplained death during sleep.) Late repeat revascularization for restenosis in the PCI plus PTMR treated target vessel was required in 19.2% of patients, and an additional 11.5% of patients had class III-IV angina at 6-month follow-up. CONCLUSIONS: These data demonstrate that in a patient population at high risk for restenosis, recently created PTMR channels are not protective against severe ischemia caused by acute vessel closure and that late symptomatic restenosis after PCI may still frequently occur despite PTMR in the same region.

Early and late quantitative angiographic results of vein graft lesions treated by excimer laser with adjunctive balloon angioplasty.

BACKGROUND: Percutaneous excimer laser coronary angioplasty (PELCA) has been approved for treatment of diseased saphenous vein bypass grafts. However, detailed and complete quantitative angiographic analysis of immediate procedural and late follow-up results has not been performed. METHODS AND RESULTS: PELCA using the CVX-300 excimer laser system was performed in 125 bypass lesions (mean graft age, 96 +/- 53 months; range, 2 to 240 months) in 106 consecutive patients at eight centers. Quantitative analyses of the procedural and follow-up angiograms were done with the Cardiac Measurement System. Stand-alone PELCA was done in 21 lesions (17%). Lesions were located at the ostium (20%), body (67%), or distal anastomosis (13%). The graft reference diameter was 3.26 +/- 0.79 mm (mean +/- SD). Minimal lumen diameter increased from 1.09 +/- 0.52 mm before treatment to 1.61 +/- 0.69 mm after laser and 2.18 +/- 0.63 mm after adjunctive balloon dilation (P < .001) but had declined at follow-up to 1.40 +/- 1.17 mm. Dissections were evident in 45% of lesions after laser treatment (types A and B, 27%; types C through F, 18%), including 7% occlusions. Angiographic success (< or = 50% diameter stenosis [% DS]) was 54% after laser and 91% after adjunctive PTCA, with an overall clinical success rate of 89%. In-hospital complications were death, 0.9%; myocardial infarction (Q-wave and non-Q-wave), 4.5%; and bypass surgery, 0.9%. Independent predictors of % DS after laser were reference diameter, lesion length, and minimal lumen diameter before laser. At angiographic follow-up in 83% of eligible patients, the restenosis rate per lesion (DS > 50%) was 52%, including 23 occlusions (24%). The only independent predictor of increased % DS at follow-up was lesion symmetry. Logistic regression indicated that smaller reference diameter was an independent predictor of late occlusion. Overall 1-year mortality was 8.6%. Actuarial event-free survival (freedom from death, myocardial infarction, bypass surgery, or target vessel percutaneous transluminal coronary angioplasty) was 48.2% at 1 year. CONCLUSIONS: Excimer laser angioplasty with adjunctive balloon angioplasty can be safely and successfully performed in diseased, old saphenous vein bypass graft lesions considered at high risk for reintervention. The extent of laser ablation remains limited by the diameter and effectiveness of the catheters. Late restenosis and, in particular, total occlusion mitigate the early benefits of the procedure. Other approaches such as the routine use of additional anticoagulation (eg, warfarin) should be considered to reduce the risk of late occlusions and restenosis after laser angioplasty of bypass grafts.

The use of two-dimensional echocardiography during catheter ablation of the atrioventricular node.

Atrioventricular nodal catheter ablation has proved an effective option in patients with drug-refractory, uncontrolled, supraventricular tachyarrhythmias; however, many complications in the immediate post ablative period relate to direct myocardial damage due to the electrical current generated by the catheter. The authors used two-dimensional echocardiography in a 57-year-old female patient with recurrent uncontrolled rapid ventricular rates despite multiple antiarrhythmic medications, in an attempt to identify the sequence of events responsible for complications of the ablation procedure. The echocardiographic images showed evidence of an explosion: microbubbles outlining an expanding force were seen which, if contained in a confined space such as the coronary sinus, might explain previously observed mechanical damage. Two-dimensional echocardiography may be useful for continual monitoring of catheter position during ablation.

Severe congestive heart failure and cardiomyopathy as a complication of myotonic dystrophy in pregnancy.

The pregnancy of a patient with myotonic dystrophy and heart failure due to cardiac involvement is described. Endomyocardial biopsy was performed at 32 weeks' gestation with echocardiographic guidance to establish the diagnosis. Severe congestive heart failure, refractory to conventional therapy, was encountered. Continuous arteriovenous hemofiltration was used to relieve pulmonary edema before cesarean delivery.

Response of extremely hypoxic cells to hyperthermia: survival and oxygen enhancement ratios.

Chinese hamster V79 cells and mouse EMT6 cells were made extremely hypoxic with a chamber technique that relies upon gas exchange rather than respiration-assisted oxygen depletion. Cells in these chambers were treated with heat (43degrees C) or heat plus x-irradiation, and colony-forming ability was determined. Hyperthermia: (a) kills exponentially growing V79 cells more efficiently than plateau-phase cells; (b) kills euoxic and extremely hypoxic cells equally; and (c) radiosensitizes euoxic and extremely hypoxic cells to the same degree, leaving the oxygen enhancement ratio unchanged.

DIP and DIP+2 as glutathione oxidants and radiation sensitizers in cultured Chinese hamster cells.

Two diamide analogues, diazene dicarboxylic acid bis (n'-methylpiperazide) or DIP, and its bis-N'-methyl iodide salt, or DIP + 2, were tested for their ability to penetrate cultured Chinese hamster cells and oxidize intracellular glutathione. DIP penetrated the cells at a reasonable rate at 18 degrees C, 160 nmoles being required to oxidize the endogenous glutathione of 2 X 10(6) cells, but it penetrated very slowly at 0 degrees C. DIP +2 did not effectively oxidize glutathione in Chinese hamster cells, possibly because it did not enter the cells. DIP became toxic after about 10 min of exposure, but its toxicity could be moderated by using anoxic conditions. DIP, but not DIP +2, sensitized anoxic Chinese hamster cells to X-radiation by a factor of 1-5, an effect that was due entirely to removal of the shoulder from the survival curve.