Long-term changes in the response of conductance and resistance coronary vessels to endothelium-dependent and independent vasodilators. A double-blind placebo-controlled study of the effect of a 6-month treatment with cilazapril.

BACKGROUND: The aim of this study was to assess the effect of a 6-month treatment with the inhibitor of the angiotensin-converting enzyme cilazapril on the response of conductance and resistance vessels to endothelium-dependent and independent vasodilators, in a randomized placebo-controlled parallel group single center study. METHODS: Quantitative angiographic and Doppler flow time-averaged peak velocity measurements were performed in an artery with < 30% diameter stenosis after sequential selective intracoronary injection of papaverine (7 mg), acetylcholine (0.036, 0.36 and 3.6 microg/ml at 2 ml/min) and isosorbide dinitrate. Repeated assessment was performed after a 6-month treatment with cilazapril 20 mg/day or placebo. Thirty-four patients were enrolled in the study undergoing elective percutaneous coronary interventions for stable angina. Main outcome measures were percent differences from baseline and absolute measurements of mean coronary cross-sectional area, coronary flow time-averaged peak velocity and flow resistance in the initial study and at follow-up for the placebo and the treated group. RESULTS: No significant differences between the placebo and the treated group were observed in the modifications of cross-sectional area after acetylcholine and isosorbide dinitrate and in the response of time-averaged peak velocity to papaverine. After the maximal concentration of acetylcholine a high but statistically not significant increase in flow and a decrease in flow resistance were observed in the treated group (medians: 45% increase vs 4% increase for coronary flow, and 44% decrease vs 1% increase for flow resistance in the cilazapril and in the treated group, respectively, p = NS). CONCLUSIONS: In patients with coronary artery disease, a 6-month treatment with 20 mg of cilazapril/day did not modify the response to endothelium-independent and dependent vasodilators of epicardial arteries without any significant stenoses but induced a consistent, although not significant, increase in flow and decrease in flow resistance after acetylcholine.

Evaluation of the long-term functional outcome assessed by myocardial perfusion scintigraphy following excimer laser angioplasty compared to balloon angioplasty in longer coronary lesions.

OBJECTIVES: Evaluation of the long-term functional outcome assessed by exercise myocardial perfusion imaging following excimer laser angioplasty compared to balloon angioplasty in coronary lesions > 10 mm in length. BACKGROUND: Previous randomized studies evaluating the effect of coronary interventions mainly focused on the long-term clinical and angiographic outcome. The functional outcome, assessed by myocardial perfusion scintigraphy, has not been evaluated in a randomized setting. METHODS: A total of 308 patients with stable angina and a longer coronary lesion (> 10 mm) were randomized to excimer laser angioplasty or balloon angioplasty. A 99mTechnetium-2-methoxy isobutyl isonitrile (MIBI) single-photon emission computed tomography (SPECT) study was performed in 139 patients before the initial angioplasty procedure and at 6 months follow-up (73 patients in the laser group versus 66 patients in the balloon group, respectively). Exercise tolerance at follow-up was compared to baseline values by means of exercise duration and double product at peak exercise. Myocardial perfusion of the randomized vascular bed was assessed semi-quantitatively on the MIBI SPECT images. The reversible defects were graded as mild, moderate or severe. Myocardial perfusion at follow-up was expressed as a percentage reduction in incidence and grading of the reversible defects compared to baseline values. RESULTS: Forty-four (61%) patients assigned to laser angioplasty were asymptomatic at 6 months follow-up compared to 34 (52%) patients assigned to balloon angioplasty (p = NS). Improvement in exercise duration and double product were 0.7 +/- 2.1 min and 4.3 +/- 6.2 min/mmHg/l,000, respectively, in the laser group, versus 0.3 +/- 2.5 min and 3.1 +/- 5.5 min/mmHg/1,000, respectively, in the balloon group (both p = NS). The percentage reduction of reversible defects was 23% in patients assigned to laser angioplasty vs. 29% in patients assigned to balloon angioplasty (Relative risk [RR]: 0.79, 95% confidence interval [CI]: 0.40-1.57; p = 0.50). The mild, moderate and severe reversible defects improved in 44.4, 63.6 and 66.6%, respectively, in the laser angioplasty group vs. 66.6, 53.8 and 90%, respectively, in the balloon angioplasty group. None of the comparisons were significantly different. CONCLUSION: Excimer laser angioplasty compared to balloon angioplasty in coronary lesions > 10 mm in length yields a similar long-term functional outcome assessed by anginal status, exercise tolerance and myocardial perfusion.

Clinical events following excimer laser angioplasty or balloon angioplasty for complex coronary lesions: subanalysis of a randomised trial.

OBJECTIVES: To compare clinical outcome in patients with complex coronary lesions treated with either excimer laser coronary angioplasty (ELCA) or balloon angioplasty. PATIENTS AND DESIGN: 308 patients with stable angina and a coronary lesion of more than 10 mm in length were randomised to ELCA (151 patients, 158 lesions) or balloon angioplasty (157 patients, 167 lesions). The primary clinical end points were death, myocardial infarction, coronary bypass surgery, or repeated coronary angioplasty of the randomised segment during six months of follow up. Subanalysis was performed to identify a subgroup of patients with a beneficial clinical outcome following ELCA or balloon angioplasty. SETTING: Two university hospitals and one general hospital. RESULTS: There were no deaths. Myocardial infarction, coronary bypass surgery, and repeated angioplasty occurred in 4.6, 10.6, and 21.2%, respectively, of patients treated with ELCA compared with 5.7, 10.8, and 18.5%, respectively, of those treated with balloon angioplasty. ELCA did not yield a favourable clinical outcome in subgroups of patients with long (more than 20 mm) coronary lesions, calcified lesions, small diseased vessels (< or = 2.5 mm reference diameter), or total coronary occlusions. There was a worse clinical outcome in patients with tandem lesions treated with ELCA compared with balloon angioplasty (9/18 v 3/26 lesions; p = 0.01); while a trend towards an unfavourable clinical outcome was found in patients with vessels with a reference diameter of more than 2.5 mm (23/66 v 13/63 lesions, p = 0.07) and left circumflex coronary lesions (12/41 v 6/42 lesions, p = 0.08). CONCLUSIONS: The findings indicate a worse clinical outcome in patients with lesions of more than 10 mm treated with ELCA compared with balloon angioplasty who have tandem coronary lesions and in those with vessels with a reference diameter of more than 2.5 mm and left circumflex coronary lesions.

Excimer laser angioplasty versus balloon angioplasty in functional and total coronary occlusions.

Registries of excimer laser coronary angioplasty have reported good results in the treatment of complex coronary artery disease, including total or subtotal coronary occlusions. One hundred three patients (103 lesions) with a functional or total coronary occlusion were included in a randomized trial (Amsterdam-Rotterdam [AMRO] trial, total of 308 patients), 49 patients were allocated to laser angioplasty and 54 patients to balloon angioplasty. The primary clinical end points were death, myocardial infarction, coronary bypass surgery, or repeated coronary angioplasty of the randomized segment during a 6-month follow-up period. The primary angiographic end point was the minimal lumen diameter at follow-up in relation to the baseline value (net gain), as determined by an automated contour-detection algorithm. Laser angioplasty was followed by balloon angioplasty in all procedures. The angiographic success rate was 65% in patients treated with excimer laser-assisted balloon angioplasty compared with 61% in patients treated with balloon angioplasty alone. No deaths occurred. There were no significant differences between the laser angioplasty group and the balloon angioplasty group in the incidence of myocardial infarctions (1 patient vs 3, respectively, p = 0.36), coronary bypass surgery (4 patients vs 2, respectively, p = 0.34), repeat angioplasty (10 patients vs 8, respectively, p = 0.46) or primary clinical end point (15 patients vs 12, respectively, p = 0.34). The net gain in minimal lumen diameter and restenosis rate (>50% diameter stenosis at follow-up) were 0.81 +/- 0.74 mm and 66.7%, respectively, in patients treated with laser angioplasty compared with 1.04 +/- 0.68 mm and 48.5%, respectively, in patients treated with balloon angioplasty (p = 0.59 and p = 0.15, respectively). Excimer laser-assisted balloon angioplasty demonstrated no benefit over balloon angioplasty with respect to initial and long-term clinical and angiographic outcome in the treatment of patients with functional or total coronary occlusions of >10 mm in length.

Randomised trial of excimer laser angioplasty versus balloon angioplasty for treatment of obstructive coronary artery disease.

BACKGROUND: Excimer laser coronary angioplasty is reported to give excellent procedural results for treatment of complex coronary lesions, but this method has not been compared with balloon angioplasty in a randomised trial. METHODS: Patients (n = 308) with stable angina and coronary lesions longer than 10 mm on visual assessment were included. 151 patients (158 lesions) were assigned randomly to laser angioplasty and 157 (167 lesions) to balloon angioplasty. The primary clinical endpoints were death, myocardial infarction, coronary bypass surgery, or repeat coronary angioplasty of the randomised segment during 6 months of follow-up. The primary angiographic endpoint was the minimal lumen diameter at follow-up in relation to the baseline value (net gain), as determined by quantitative coronary angiography. FINDINGS: Laser angioplasty was followed by balloon angioplasty in 98% of procedures. The angiographic success rate was 80% in patients treated with laser angioplasty compared with 79% in patients treated with balloon angioplasty. There were no deaths. Myocardial infarction, coronary bypass surgery, and repeat angioplasty occurred in 4.6%, 10.6%, and 21.2%, respectively, of the patients in the laser angioplasty group compared with 5.7%, 10.8%, and 18.5% of the balloon angioplasty group. Net mean (SD) gain in minimal lumen diameter was 0.40 (0.69) mm in patients treated with laser angioplasty and 0.48 (0.66) mm in those treated with balloon angioplasty (p = 0.34). The restenosis rate (> 50% diameter stenosis) was 51.6% in the laser angioplasty group versus 41.3% in the balloon angioplasty group (p = 0.13). INTERPRETATION: Excimer laser angioplasty followed by balloon angioplasty provides no benefit additional to balloon angioplasty alone with respect to the initial and long-term clinical and angiographic outcome in the treatment of obstructive coronary artery disease.

Immediate and late outcome of excimer laser and balloon coronary angioplasty: a quantitative angiographic comparison based on matched lesions.

OBJECTIVES: This study sought to compare acute lumen changes and late lumen narrowing during and after excimer laser-assisted balloon angioplasty, measured by quantitative coronary angiography, with the immediate and long-term outcome of balloon angioplasty alone. BACKGROUND: Although excimer laser coronary angioplasty is used as an adjunct or alternative to balloon angioplasty, limited comparative data exist regarding the immediate and long-term efficacy of excimer laser-assisted balloon angioplasty versus balloon angioplasty alone. METHODS: A series of 53 lesions in 47 consecutive patients successfully treated with excimer laser-assisted balloon angioplasty were individually matched after completion of 6-month follow-up angiography with 53 successfully treated balloon angioplasty lesions according to vessel location, preprocedural minimal lumen diameter and reference diameter. Immediate and long-term angiographic results were assessed by an automated lumen contour detection algorithm. RESULTS: Before intervention in the laser and balloon angioplasty groups, respectively, minimal lumen diameter (mean +/- SD) was 0.73 +/- 0.47 and 0.74 +/- 0.46 mm, and reference diameter was 2.71 +/- 0.42 and 2.72 +/- 0.41 mm. Laser angioplasty was followed by adjunctive balloon dilation in 50 lesions. Mean balloon diameter at maximal inflation was similar in both treatment groups (2.61 +/- 0.32 and 2.65 +/- 0.38 mm, respectively), resulting in similar minimal lumen diameters after intervention of 1.77 +/- 0.41 and 1.78 +/- 0.34 mm, respectively. At follow-up angiography, minimal lumen diameter after excimer laser-assisted balloon angioplasty was 1.17 +/- 0.63 mm, and that after balloon angioplasty alone was 1.46 +/- 0.67 mm (p = 0.02). The angiographic restenosis rates at follow-up using the 50% diameter stenosis cutoff criterion were 57% and 34%, respectively (p = 0.02). CONCLUSIONS: Quantitative angiographic analysis of a matched group of 106 successfully treated coronary lesions showed a similar immediate outcome but reduced long-term efficacy of excimer laser-assisted balloon angioplasty compared with that after balloon angioplasty alone.

Differences in restenosis propensity of devices for transluminal coronary intervention. A quantitative angiographic comparison of balloon angioplasty, directional atherectomy, stent implantation and excimer laser angioplasty. CARPORT, MERCATOR, MARCATOR, PARK, and BENESTENT Trial Groups.

With the increasing clinical application of new devices for percutaneous coronary revascularization, maximization of the acute angiographic result has become widely recognized as a key factor in maintained clinical and angiographic success. What is unclear, however, is whether the specific mode of action of different devices might exert an additional independent effect on late luminal renarrowing. The purpose of this study was to investigate such a difference in the degree of provocation of luminal renarrowing (or 'restenosis propensity') by different devices, among 3660 patients, who had 4342 lesions successfully treated by balloon angioplasty (n = 3797), directional coronary atherectomy (n = 200), Palmaz-Schatz stent implantation (n = 229) or excimer laser coronary angioplasty (n = 116) and who also underwent quantitative angiographic analysis pre- and post-intervention and at 6-month follow-up. To allow valid comparisons between the groups, because of significant differences in coronary vessel size (balloon angioplasty = 2.62 +/- 0.55 mm, directional coronary atherectomy = 3.28 +/- 0.62 mm, excimer laser coronary angioplasty = 2.51 +/- 0.47 mm, Palmaz-Schatz = 3.01 +/- 0.44 mm; P < 0.0001), the comparative measurements of interest selected were the 'relative loss' in luminal diameter (RLoss = loss/vessel size) to denote the restenosis process, and the 'relative lumen at follow-up' (RLfup = minimal luminal diameter at follow up/vessel size) to represent the angiographic outcome. For consistency, lesion severity pre-intervention was represented by the 'relative lumen pre' (RLpre = minimal luminal diameter pre/vessel size) and the luminal increase at intervention was measured as 'relative gain' (relative gain = gain/ vessel size). Differences in restenosis propensity between devices was evaluated by univariate and multivariate analysis. Multivariate models were constructed to determine relative loss and relative lumen at follow-up, taking account of relative lumen pre-intervention, lesion location, relative gain, vessel size and the device used. In addition, model-estimated relative loss and relative lumen at follow-up at given relative lumen pre-intervention relative gain and vessel size, were compared among the four groups. Significant differences were detected among the groups both with respect to these estimates, as well as in the degree of influence of progressively increasing relative gain, on the extent of renarrowing (relative loss) and angiographic outcome (relative lumen at follow-up), particularly at higher levels of luminal increase (relative gain). Specifically, lesions treated by balloon angioplasty or Palmaz-Schatz stent implantation (the predominantly 'dilating' interventions) were associated with more favourable angiographic profiles than directional atherectomy or excimer laser (the mainly 'debulking' interventions). Significant effects of lesion severity and location, as well as the well known influence of luminal increase on both luminal renarrowing and late angiographic outcome were also noted. These findings indicate that propensity to restenosis after apparently successful intervention is influenced not only by the degree of luminal enlargement achieved at intervention, but by the device used to achieve it. In view of the clinical implications of such findings, further evaluation in larger randomized patient populations is warranted.

Quantitative angiographic comparison of elastic recoil after coronary excimer laser-assisted balloon angioplasty and balloon angioplasty alone.

OBJECTIVES: Coronary lumen changes during and after excimer laser-assisted balloon angioplasty were measured by quantitative coronary angiography, and the results were compared with the effects of balloon angioplasty alone. BACKGROUND: Reduction of atherosclerotic tissue mass by laser ablation in the treatment of coronary artery disease may be more effective in enlarging the lumen than balloon angioplasty alone. METHODS: A series of 57 consecutive coronary lesions successfully treated by xenon chloride excimer laser-assisted balloon angioplasty were individually matched with 57 coronary artery lesions successfully treated by balloon angioplasty alone. The following variables were measured by quantitative coronary analysis: 1) ablation by laser, 2) stretch by balloon dilation, 3) elastic recoil, and 4) acute gain. RESULTS: Matching by stenosis location, reference diameter and minimal lumen diameter resulted in two comparable groups of 57 lesions with identical baseline stenosis characteristics. Minimal lumen diameter before excimer laser-assisted balloon angioplasty and balloon angioplasty alone were (mean +/- SD) 0.73 +/- 0.44 and 0.74 +/- 0.43 mm, respectively. Laser ablation significantly improved minimal lumen diameter by 0.56 +/- 0.44 mm before adjunctive balloon dilation. In both treatment groups, similar-sized balloon catheters (2.59 +/- 0.35 and 2.56 +/- 0.40 mm, respectively) were used. After laser-assisted balloon angioplasty, elastic recoil was 0.84 +/- 0.30 mm (32% of balloon size), which was identical to that after balloon angioplasty alone, namely, 0.82 +/- 0.32 mm (32%). Consequently, both interventions resulted in similar acute gains of 1.02 +/- 0.52 and 1.00 +/- 0.56 mm, respectively. Minimal lumen diameter after intervention was equal in both groups: 1.75 +/- 0.35 and 1.75 +/- 0.34 mm, respectively. The statistical power of this study in which a 25% difference in elastic recoil (0.2 mm) between groups was considered clinically important was 95%. CONCLUSIONS: In matched groups of successfully treated coronary lesions, xenon chloride excimer laser ablation did not reduce immediate elastic recoil after adjunctive balloon dilation or improve the final angiographic outcome compared with balloon angioplasty alone using similar-sized balloon catheters.

The development of transplant coronary artery disease after cardiac transplantation is correlated with a predominance of CD8+ T lymphocytes in endomyocardial biopsy derived T cell cultures.

Long-term survival of heart transplant recipients is limited by the development of transplant coronary artery disease (TCAD). We analysed whether the development of TCAD is correlated with the incidence of acute rejection episodes, with the formation of anti-HLA antibodies or with the composition and function of T lymphocyte cultures derived from endomyocardial biopsies. TCAD was assessed by visual analysis of annually performed coronary angiograms and defined as the presence of all vascular changes, including minor wall irregularities. One year after transplantation, 31 of the 77 patients studied had TCAD (40%). The median age and mean number of HLA mismatches in patients with or without TCAD were highly comparable. The patient groups did not differ in incidence of acute rejection episodes, nor in percentage of endomyocardial biopsies yielding T cell cultures. At 1 year after transplantation, lymphocyte cultures from 18/31 TCAD+ patients (58%) and 27/46 TCAD- patients (57%) were analysed. The TCAD+ patients had, compared with the TCAD- patients, a higher median percentage of CD8+ T cells (71% versus 25%, P = 0.06) and a lower median percentage of CD4+ T cells (4% versus 40%, P = 0.04). Similar differences were found in a longitudinal analysis of the culture results of endomyocardial biopsies (EMBs) obtained during the first year. The cytotoxic reactivity of the cultures against donor HLA class I or class II antigens was comparable in the two groups, although a difference in recognition of heart specific antigens remains possible. The fact that EMB-derived cultures from TCAD+ and TCAD- patients differed in T cell phenotype populations gives some support to the hypothesis that cellular immunological processes are involved in the development of TCAD. However, while the median values differed, the overlap of the percentages of CD8+ cells in cultures from TCAD- and TCAD+ patients shows that other factors besides CD8+ T cells also play a role.

Response of conductance and resistance coronary vessels to scalar concentrations of acetylcholine: assessment with quantitative angiography and intracoronary Doppler echography in 29 patients with coronary artery disease.

Abnormal vasoreactivity of the large conductance arteries has been observed in the presence of impaired endothelial function. More recently, experimental and clinical reports have shown that in early coronary atherosclerosis the impairment of the endothelium-mediated vasodilatation also involves the resistance arteries. The aim of this study is the correlation of endothelium-dependent vasodilatation of conductance and resistance vessels in coronary arteries without significant stenoses. In 29 patients (aged 57 +/- 9 years, 24 men and 5 women) undergoing coronary angioplasty, a Doppler guide wire and a perfusion catheter were introduced into the proximal segment of an artery with less than 30% diameter stenosis. Selective infusions of papaverine (bolus of 7 mg), acetylcholine (continuous infusion of 0.036, 0.36, and 3.6 micrograms/ml at a flow rate of 2 ml/min), and isosorbide dinitrate (bolus of 3 mg) were sequentially performed. Heart rate, aortic blood pressure, and blood flow velocity were continuously measured. Mean cross-sectional areas of a proximal and a distal arterial segment were measured in baseline conditions, at the end of each infusion of acetylcholine, and at the peak effect of isosorbide dinitrate with quantitative angiography (CAAS System; Pie Medical Data, Maastricht, The Netherlands). Coronary blood flow was calculated from the time-averaged flow velocity and the cross-sectional area at the site of the Doppler sample volume. Coronary flow resistance was calculated as mean aortic pressure divided by coronary flow. All of the concentrations of acetylcholine induced a significant vasoconstriction of the studied artery. At the maximal concentration of acetylcholine all but three patients (90%) showed a reduction of cross-sectional area (-24% +/- 20% and -22% +/- 20% for the proximal and distal segments, respectively, p < 0.00001). Flow velocity showed a significant increase only with the two highest concentrations of acetylcholine. The maximal concentration induced a 105% +/- 138% increase from the baseline flow velocity (p < 0.001). The coronary flow changes after acetylcholine showed a large interpatient variability, with a mean increase from baseline after the highest dose of +43% +/- 85% (range, -60% +/- 239%), with the presence of a flow reduction in 10 patients (35%). No clinical or angiographic variables showed a significant correlation with the cross-sectional area, flow velocity, and flow changes after infusion of acetylcholine.(ABSTRACT TRUNCATED AT 400 WORDS)

Heart function after injection of small air bubbles in coronary artery of pigs.

By its nature, vaporization of atherosclerotic plaques by laser irradiation or spark erosion may produce a substantial amount of gas. To evaluate the effect of gas embolism possibly caused by vaporization techniques, air bubbles with diameters of 75, 150, or 300 microns, each in a volume of 2 microliters/kg, were selectively injected subproximal in the left anterior descending coronary artery of seven anesthetized pigs (28 +/- 3 kg). Systemic hemodynamics such as heart rate, left ventricular pressure and its peak positive first derivative, and mean arterial pressure did not change after air injection, whereas there was a minor change in peak negative first derivative of left ventricular pressure. After injection of air bubbles there was a maximal relative reduction of systolic segment shortening (SS) in the myocardium supplied by the left anterior descending coronary artery of 27, 45, and 58% for 75-, 150-, and 300-microns bubbles, respectively, and a relative increase of postsystolic SS (PSS) of 148, 200, and 257% for 75-, 150-, and 300-microns bubbles, respectively. Recovery of SS and PSS started after 2 min and was completed after 10 min. A difference in SS and PSS changes between different bubble size injections could be demonstrated. From this study it is clear that depression of regional myocardial function after injection of air bubbles could pass unnoticed on the basis of global hemodynamic measurements.

Rapid progression of septal hypertrophy in an adult with hypertrophic cardiomyopathy and excimer laser-treated coronary artery disease.

We present the case of a 55-year-old man with rapid progression from asymmetrical septal hypertrophy to hypertrophic obstructive cardiomyopathy over a 1-year period leading to persistent anginal symptoms despite adequate treatment of his concomitant coronary artery disease. The potential mutagenic side effects of XeCl excimer laser-radiation that was used to remove the arteriosclerotic plaque from the left anterior descending coronary artery may have contributed to the sudden increase in septal thickness.

Intracoronary pressure and flow velocity with sensor-tip guidewires: a new methodologic approach for assessment of coronary hemodynamics before and after coronary interventions.

The use of miniaturized pressure and velocity sensors mounted on angioplasty guidewires allows the simultaneous measurement of coronary blood flow velocity and transstenotic pressure gradient, 2 parameters that, combined, should perfectly characterize stenosis hemodynamics. The aim of this article is assessment of the changes in coronary blood flow velocity observed with a Doppler-tipped angioplasty guidewire in 35 patients undergoing balloon angioplasty. We also report our initial experience in 16 patients with the combined use of sensor-tip pressure and Doppler guidewires, and we discuss the application of new methodologic approaches for the study of the coronary circulation allowed by these techniques, such as the instantaneous assessment of the flow velocity/pressure and pressure gradient/flow velocity relations. Before and after angioplasty, flow velocity measurements were obtained distal to the stenosis, both in baseline conditions and after intracoronary injection of 8-12.5 mg of papaverine. The Doppler guidewire was left in place during the dilation procedure and the Doppler signal was continuously recorded during balloon inflation and after deflation to monitor the development of collateral flow, the restoration of flow after balloon deflation, the phase of postocclusive reactive hyperemia, and, incidently, the development of flow-limiting complications. Merits and pitfalls of several flow velocity parameters (average peak velocity, coronary flow velocity reserve, diastolic/systolic velocity ratio), as well as of parameters derived from the combination of pressure and velocity measurements (transstenotic pressure gradient/flow velocity relation and instantaneous diastolic hyperemic flow velocity/pressure relation) were evaluated in 35 patients with, and 37 without, significant coronary stenoses.(ABSTRACT TRUNCATED AT 250 WORDS)

Restenosis after directional coronary atherectomy and balloon angioplasty: comparative analysis based on matched lesions.

OBJECTIVES: Late lumen narrowing after directional coronary atherectomy was assessed by quantitative coronary angiography and compared with that after balloon angioplasty. BACKGROUND: Directional coronary atherectomy has been introduced as an alternative technique for balloon angioplasty and may reduce the incidence of restenosis. METHODS: A prospectively collected consecutive series of 87 native coronary artery lesions successfully treated with atherectomy were matched with 87 coronary artery lesions selected from a consecutive series of lesions that had been successfully dilated by balloon angioplasty. Late angiographic analysis was performed in 158 lesions. The net gain index represents the ultimate gain in minimal lumen diameter at follow-up study, normalized for the vessel size. This index is the result of the relative gain attained during the procedure (the ratio of the change in minimal lumen diameter and reference diameter) and the relative loss observed during the follow-up period (the ratio of the change in minimal lumen diameter during the follow-up period and the reference diameter). RESULTS: Matching for clinical and angiographic variables resulted in two comparable groups with similar baseline stenosis characteristics. Atherectomy resulted in a more pronounced increase in minimal lumen diameter than did balloon angioplasty (mean +/- SD 1.17 +/- 0.29 to 2.44 +/- 0.42 mm vs. 1.21 +/- 0.38 to 2.00 +/- 0.36 mm, p < 0.001). However, this favorable immediate result was subsequently lost during late angiographic follow-up, so that the minimal lumen diameter at follow-up and the net gain index did not differ significantly between the two groups (1.76 +/- 0.62 vs. 1.77 +/- 0.59 mm, p = 0.93, and 0.18 +/- 0.19 vs. 0.17 +/- 0.17, p = 0.70). Consequently, the relative gain and relative loss were higher in the atherectomy group. For both techniques, the relative gain was linearly related to the relative loss but the slope of the regression line was steeper for atherectomy, suggesting that the relative loss in the atherectomy group is proportionally even larger for a given relative gain compared with that in the angioplasty group. CONCLUSIONS: In matched groups of patients, atherectomy induces a greater initial gain in minimal lumen diameter than does balloon angioplasty. However, the vascular wall injury induced by the device is of a different nature (debulking vs. dilating) that leads to more relative loss over the follow-up period in the atherectomy group.

Excimer laser coronary angioplasty in The Netherlands: preamble for a randomized study.

The immediate outcome of ELCA by XeCl excimer laser radiation is described in 53 patients who were selected to undergo ELCA from December 1990 to September 1991 in two centers that are currently performing ELCA in the Netherlands. Immediate success rates on the basis of visual assessment of the angiogram were as follows. Laser success (> 20% reduction of diameter stenosis after ELCA alone) was observed in 77% of patients, procedural success (< 50% residual stenosis after ELCA with or without adjunctive balloon dilatation [PTCA]) in 91%, and clinical success (procedural success without clinical complications) in 83% of patients. Quantitative coronary angiography by automated contour detection was performed in 31 patients who underwent ELCA in the Thoraxcenter. The minimal luminal diameter (mean +/- SD) of the treated coronary segments increased from 0.77 +/- 0.41 mm to 1.24 +/- 0.25 mm after ELCA and further to 1.67 +/- 0.29 mm after adjunctive PTCA in 25 patients. The present experience is put in perspective of results initially reported by other centers and compared with data from multicenter registries of ELCA. Finally, a short description is given of the design of a prospective, randomized trial of ELCA versus conventional PTCA (AMRO trial).

Phenotype of endomyocardial biopsy-derived T-lymphocyte cultures and chronic rejection after heart transplantation.

Chronic rejection (CR) is a major problem in long-term survival in heart transplantation. We analysed whether the occurrence of CR correlates with the incidence of acute rejections (AR) or with characteristics of endomyocardial biopsy-derived cell cultures. CR was diagnosed by annual angiography and defined as all coronary vascular changes. One year after transplantation 24 of the 63 patients had CR (38%). The incidence of AR in CR+ and CR- patients was comparable. The patients in both groups had similar individual median percentages of EMB-yielding cell cultures. During the first year the CR- patients had more cultures in which at least 60% of the cells were CD4+ T cells (50% vs 37%, P = 0.05), due to a stronger CD4 predominance in the first 6 months. In the second year the CD4 predominance in the patients diagnosed as CR+ after 1 year tended to be higher (P = 0.08). The patients had comparable percentages of cultures predominated by CD8+ T cells, gammadelta T cells or NK cells, irrespective of the time interval. These results might indicate that CD4+ T lymphocytes play a dual role in the aetiology of CR.

Effects of varying argon ion laser intensity and exposure time on the ablation of atherosclerotic plaque.

Using continuous wave (CW) argon ion laser light, a total of 253 laser exposures of varying power (1.5, 3, 5, 8 or 10 W) and duration (20-1,333 ms) were delivered to four segments of human atheromatous aorta obtained at autopsy. Exposure conditions were controlled by using an optically shielded laser catheter that provided a 500 micron spot of light of known power. Two thresholds for consistently reproducible ablation could be defined-an intensity threshold at 25.5 W/mm2 and a fluence threshold at 3.2 J/mm2. Above threshold, a fluence of 5.1 J/mm2 was found to produce the most efficient ablation, ie, removed the greatest volume (mm3) per energy delivered (J) compared to other fluence levels employed (p less than 0.0001). Between aortic segments, however, considerable variability in efficiency (mm3/J) was observed, possibly owing to different optical properties and/or plaque composition. Low-intensity laser radiation produced inconsistent ablation and extensive coagulation effects to surrounding tissue. When a fluence of 5.1 J/mm2 was constructed with a high-intensity laser beam and a short exposure time, consistent and efficient tissue removal resulted without histologic evidence of coagulation necrosis.

A model for thermal ablation of biological tissue using laser radiation.

We present a theory of thermal laser ablation based on the heat equation and on an energy balance equation derived from it. Ablation is assumed to be brought about by the heating and evaporation of tissue water. The model is three-dimensional, and scattering and the water-steam phase transition are explicitly taken into account. The model predicts threshold parameters and a steady-state ablation velocity in terms of the optical and thermal properties of the tissue and the laser beam intensity and spot diameter.