Sipke Strikwerda

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)

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.

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 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.

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)

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 (⩽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.

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.

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).

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.

Percutaneous directional atherectomy for discrete coronary lesions in cardiac transplant patients

petted and may be the underlying pathogenesis of occult renal insufficiency, as in the case presented. Furthermore, the onset of the syndrome may not be immediate and may be delayed following an invasive procedure. The proposed mechanism may be endothelial injury at the time of arterial manipulation (surgery) or catheter-related endothelial denudation that places the cholesterol-rich extracellular matrix in direct contract with the blood. This allows the turbulent blood to dislodge fragments from these now unroofed ulcerated plaques. It may also be possible that embolism may occur spontaneously as a result of endothelial injury related to rheologic factors. Unfortunately, there are no ideal or effective treatment methods for the prevention or treatment of this syndrome. Anticoagulant therapy has been proposed as a possible preventive treatment, as the finding of superimposed thrombus is common. There are, however, no studies to support the use of anticoagulation and its potential adverse effects such as major hemorrhage in the elderly and the potential for plaque hemorrhage, as has been proposed in the past. If investigation of the aorta by TEE demonstrates significant atheromatosis with embolic potential, we recommend the substitution of noninvasive vascular testing such as contrast computed tomography (CT) or magnetic resonance imaging (MRI) when feasible. The information obtained during transesophageal study may also be valuable to the cardiovascular surgeon, who at the time of surgery may be able to perform endarterectomy, as has been suggested by Tunick et a1.5 In conclusion, the case presented is the first report of a patient in which aortic atheromas were documented in vivo and a subsequent tissue (renal) biopsy demonstrated arterial embolization of atherosclerotic debris. Thus TEE is useful for localizing aortic atheromatosis and may help identify patients who are at risk to develop cholesterol embolism associated with intraaortic catheter placement. Furthermore, as suggested by Tunick et al.,7 protruding atheromas in the thoracic aorta may be an independent risk factor for systemic embolization.