M. Haude

Quantitative analysis of elastic recoil after balloon angioplasty and after intracoronary implantation of balloon-expandable Palmaz-Schatz stents

OBJECTIVESnThe purpose of this study was to measure elastic recoil from sequential angiograms after balloon angioplasty and after implantation of a balloon-expandable Palmaz-Schatz stent in the same patient, and to compare the results with the late angiographic outcome.nnnBACKGROUNDnThe immediate result of coronary balloon angioplasty is influenced by plastic deformation, primarily of the atherosclerotic plaque, and by elastic recoil, primarily of the less or nondiseased vessel circumference.nnnMETHODSnThe extent of elastic recoil was measured quantitatively as the difference between maximal balloon size and the resulting vessel diameter or cross-sectional area.nnnRESULTSnAnalysis was performed in 60 patients who received a single stent for late restenosis after initially successful coronary balloon angioplasty. Minimal lumen diameter (minimal cross-sectional area) was 0.98 +/- 0.43 mm (0.97 +/- 0.67 mm2) before balloon angioplasty, 2.06 +/- 0.36 mm (3.68 +/- 1.17 mm2) after angioplasty (both p < 0.001 vs. values before angioplasty) and 2.98 +/- 0.26 mm (7.12 +/- 1.28 mm2) after stenting (both p < 0.001 vs. postangioplasty results). No significant changes in vessel reference diameters or areas were measured. Mean balloon/artery ratios were similar in both procedures, ranging from 0.93 to 0.96. The calculated mean elastic recoil was 0.98 +/- 0.50 mm in diameter (31%) and 3.67 +/- 2.05 mm2 in area (48%) after balloon angioplasty compared with 0.10 +/- 0.07 mm (3.5%) and 0.38 +/- 0.36 mm2 (5.1%) after stenting. Increasing balloon sizes induced increased vessel stretch, which was followed by increased elastic recoil in the angioplasty group in contrast to the stenting group. Short, noncalcified and eccentric lesions tend to be associated with increased recoil after balloon angioplasty. Overdilation or underdilation in one of the procedures, changes in postprocedural vasomotion or postprocedural thrombus formation was not responsible for this outcome. After 6 months mean minimal lumen diameter was 2.39 +/- 0.58 mm, suggesting a mean hyperplasia of 0.59 +/- 0.51 mm. Twelve patients (20%) had a follow-up diameter that was equal to or less than the mean postangioplasty result and eight patients (14%) had a diameter stenosis of > 50%.nnnCONCLUSIONSnThe implantation of a Palmaz-Schatz stent almost completely eliminates the decrease in vessel dimensions caused by elastic recoil and therefore diminishes the impact of hyperplasia and reduces the rate of restenosis.

Results of intracoronary stents for management of coronary dissection after balloon angioplasty

Dissections after coronary balloon angioplasty are risk factors for acute or subacute vessel closures. Intracoronary stenting was developed to avoid these complications by pressing the intimal and medial flaps against the vessel wall, thus reducing the risk of acute thrombosis. A total of 22 stents were implanted into the coronary arteries of 15 patients with dissections after balloon angioplasty causing angina pectoris or ischemic electrocardiographic changes. Stent delivery was successful in all cases. In 1 patient acute stent thrombosis was documented and treated successfully by thrombolytic therapy. Another patient underwent coronary artery bypass surgery 24 hours later because of persisting angina. Angiograms after 24 hours documented vessel patency in the remaining 14 patients. Late control angiograms after 4 to 6 months were obtained in 12 of 14 patients. Vessel patency without significant restenosis was observed in 8 patients, restenosis in 3 and reocclusion in 1 patient. All 3 patients with multiple stent implantation had restenosis (n = 2) or reocclusion (n = 1), compared with 1 patient with single stent implantation. Thus, intracoronary stenting appears to be a secure and effective method of handling bailout situations caused by dissection after balloon angioplasty, with good long-term results when only a single stent is implanted.

Comparison of Myocardial Perfusion Reserve Before and After Coronary Balloon Predilatation and After Stent Implantation in Patients With Postangioplasty Restenosis

BACKGROUNDnStents provide a scaffold for coronary arteries after angioplasty and inhibit elastic recoil.nnnMETHODS AND RESULTSnIn 25 patients with postangioplasty restenosis of the left anterior descending artery, ECG-gated digital subtraction coronary angiograms were recorded at baseline and during hyperemia (12 mg papaverine IC) before and after balloon predilatation (PTCA), after implantation of a Palmaz-Schatz stent, and after 6 months. Densitometric evaluation revealed different time and density parameters to calculate two definitions of myocardial perfusion reserve (MPR1 and MPR2) and maximum flow ratio (MaxFR). Poststenotic MPR1 increased from 1.57 +/- 0.14 to 2.59 +/- 0.86 after PTCA and to 3.10 +/- 0.41 after stenting, with 2.90 +/- 0.65 at follow-up (ANOVA, P < .05), while reference MPR1 remained unchanged at 3.10 +/- 0.40. Poststenotic MPR2 increased from 1.36 +/- 0.28 to 2.50 +/- 1.20 and to 3.40 +/- 0.58, respectively, with 3.20 +/- 0.92 at follow-up (ANOVA, P < .05), while reference MPR2 remained unchanged at 3.40 +/- 0.60. MaxFR was 2.13 +/- 0.53 after PTCA, elasticity 2.83 +/- 0.35 after stenting, and 2.73 +/- 0.58 at follow-up (ANOVA, P < .05). A good correlation was found between minimal stenotic luminal diameter and MPR1 or MPR2 (r = .87 and r = .94) and between luminal gain and MaxFR (r = .75). A negative correlation was measured between recoil and MPR1, MPR2, and MaxFR (r = -.80, r = -.86, and r = -.83). At follow-up, a steeper correlation was found between MPR and minimal stenosis diameter (MPR1: slope, 0.52 versus 0.91; MPR2: slope, 1.48 versus 1.95) and between MaxFR and net lumen gain (slope, 0.78 versus 1.27).nnnCONCLUSIONSnCoronary stent implantation in patients with postangioplasty restenosis normalized poststenotic myocardial perfusion immediately as a result of a larger postprocedural lumen and a more pronounced inhibition of elastic recoil. After 6 months this benefit was sustained despite progressive lumen loss.

Laser angioplasty of restenosed coronary stents: Results of a multicenter surveillance trial

OBJECTIVESnThis study evaluated safety and efficacy of excimer laser angioplasty for treatment of restenosed or occluded coronary stents.nnnBACKGROUNDnBalloon angioplasty of in-stent restenosis is limited by a high recurrence rate. Debulking by laser angioplasty is a novel concept to treat in-stent restenosis.nnnMETHODSnA total of 440 patients with restenoses or occlusions in 527 stents were enrolled for treatment with concentric or eccentric laser catheters and adjunctive balloon angioplasty.nnnRESULTSnLaser angioplasty success (< or =50% diameter stenosis after laser treatment or successful passage with a 2.0-mm or 1.7-mm eccentric laser catheter) was achieved in 92% of patients. Adjunctive balloon angioplasty was performed in 99%. Procedural success (laser angioplasty success followed by < or =30% stenosis with or without balloon angioplasty) was 91%. There was neither a significant difference in success with respect to lesion length, nor were there differences between small and large vessels or native vessels and vein grafts. Success was higher and residual stenosis lower using large or eccentric catheters. Serious adverse events included death (1.6%, not directly laser catheter related), Q-wave myocardial infarction (0.5%), non-Q-wave infarction (2.7%), cardiac tamponade (0.5%) and stent damage (0.5%). Perforations after laser treatment occurred in 0.9% of patients and after balloon angioplasty in 0.2%. Dissections were visible in 4.8% of patients after laser treatment and in 9.3% after balloon angioplasty. Reinterventions during hospitalization were necessary in 0.9% of patients; bypass surgery was performed in 0.2%.nnnCONCLUSIONSnExcimer laser angioplasty with adjunctive balloon angioplasty is a safe and efficient technology to treat in-stent restenoses. These data justify a randomized comparison with balloon angioplasty.

Tomographic left ventricular volume determination in the presence of aneurysm by three-dimensional echocardiographic imaging. I: Asymmetric model hearts

To improve the accuracy of measurements of left ventricular volume in the presence of an aneurysm, we used three-dimensional echocardiographic imaging to analyze the shape of left ventricles in 23 asymmetric model hearts with eccentric aneurysms of different sizes, shapes, and localizations. A standard 3.75 MHz ultrasound probe with a rotation motor device was used to obtain a three-dimensional data set. By rotating the probe stepwise 1 degree, 180 radial ultrasound pictures were digitized. On the basis of the three-dimensional data set, the following parameters were determined and compared with the dimensions of the model hearts obtained by direct measurement: total left ventricular volume (LVV), aneurysm volume, area of the aneurysms base, the longest aneurysm long diameter, and the longest aneurysm cross diameter. In addition, quantification of LVV by three-dimensional echocardiography was compared with biplane two-dimensional echocardiographic measurement according to the disk method. Good agreements were found for LVV measured by both techniques, three-dimensional echocardiographic and direct measurement (mean of differences = 0.91 ml; SD of differences = +/- 6.23 ml; line of regression y = 1.07 x - 14.24 ml; r = 0.968; standard error of the estimate [SEE] = +/- 6.17 ml), aneurysm volume (mean of differences = 0.43 ml; SD of differences = +/- 2.14 ml; line of regression y = 1.05 x - 0.81 ml; r = 0.996; SEE = +/- 1.96 ml), area of the aneurysms base (mean of differences = 0.24 cm2; SD of differences = +/- 1.72 cm2; line of regression y = 1.02 x - 0.02 cm2; r = 0.981; SEE = +/- 1.75 cm2), the longest aneurysm long diameter (mean of differences = -0.26 mm; SD of differences = +/- 1.60 mm; line of regression y = 0.97 x + 1.34 mm; r = 0.996; SEE = +/- 1.54 mm), and the longest aneurysm cross diameter (mean of differences = 1.35 mm; SD of differences = +/- 3.94 mm; line of regression y = 0.95 x + 3.17 mm; r = 0.941; SEE = +/- 3.99 mm). In contrast, in these extremely asymmetric-shaped model hearts, agreement between biplane two-dimensional echocardiographic and both direct LVV measurement (mean of differences = 7.8 ml; SD of differences = +/- 20.8 ml; line of regression y = 1.48 x - 92.45 ml; r = 0.874; SEE = +/- 18.36 ml) and three-dimensional echocardiographic measurements (mean of differences = -7.6 ml; SD of difference = +/- 18.1 ml; line of regression y = 0.59 x + 80.98 ml; r = 0.908; SEE = +/- 10.36 ml) was poor. Thus tomographic three-dimensional echocardiography allowed accurate volume determination of asymmetric model hearts in the shape of left ventricles with eccentric aneurysms.

Sublingual administration of captopril versus nitroglycerin in patients with severe congestive heart failure

Angiotensin-converting enzyme inhibition has proven to be a successful approach for the long-term treatment of patients with congestive heart failure. This investigation compared the acute hemodynamic changes after sublingual administration of the angiotensin-converting enzyme inhibitor captopril with those after nitroglycerin. A total of 24 patients with severe left heart failure (New York Heart Association classes III and IV) were given 25 mg captopril and 0.8 mg nitroglycerin sublingually in this randomized, cross-over study. Hemodynamic monitoring revealed a clear improvement in pre- and afterload parameters for both drugs (P less than 0.01 and P less than 0.001), while captopril induced a higher increase in cardiac index (+49.2% vs. +25%), stroke volume index (+53.5% vs. +25.7%), and stroke work index (+55% vs. +28%) than nitroglycerin (P less than 0.001). Although not statistically significant, the onset of change for most hemodynamic parameters was measured earlier after nitroglycerin (after 12-19 vs. 16-22 minutes). Captopril revealed later peak effects (after 47-84 vs. 25-55 minutes, P less than 0.001) and a longer sustained improvement in hemodynamic values (return to baseline values after 117-162 vs. 68-120 minutes, P less than 0.001). No side effects occurred after either captopril or nitroglycerin in this study. Thus, these results indicate there is an early improvement in hemodynamic parameters after the sublingual administration of both drugs in patients with severe congestive heart failure, and that captopril induces a more pronounced and prolonged improvement than nitroglycerin.

Extramural vessel wall hematoma causing a reduced vessel diameter after coronary stenting: Diagnosis by intravascular ultrasound and treatment by stent implantation

An extramural vessel wall hematoma occurred immediately after implanting a coronary stent in an in-stent-restenosis of the intermedius branch. Angiography showed a significant luminal reduction distal to the intervention site. Intravascular ultrasound revealed an extramural echolucent zone compressing the vessel lumen. Stent implantation compressed the hematoma and allowed adequate myocardial perfusion. This demonstrates the value of intravascular ultrasound (IVUS) in cases of unusual angiographic results which can help to manage complications after coronary intervention.

Notfallmäßige Stent-Implantation in dem Bereich einer ausgedehnten Muskelbrücke des Ramus interventricularis anterior nach postinterventioneller Dissektion

Bei einem 64jährigen Patienten mit progredienter Angina-pectoris-Symptomatik zeigte die koronare Angiographie eine Muskelbrücke im Ramus interventricularis anterior. Auch die anschließend durchgeführten intrakoronare Ultraschall-(ICUS) und Doppler-Untersuchungen zeigten eine signifikante systolische Flächenreduktion um 35,9% und eine eingeschränkte koronare Flußgeschwindigkeitsreserve (CFGR) von 2,6. Proximal sowie auch distal der Muskelbrücke wurden zwei hochgradige Stenosen diagnostiziert; zunächst wurde an der distalen Läsion eine perkutane transluminale koronare Angioplastie (PTCA) durchgeführt. Wegen einer flußlimitierenden Dissektion wurde die Indikation zu einer Stent-Implantation gestellt. Da der Übergang zwischen dem Stent und der Muskelbrücke ein erhebliches Abknicken mit Lumenreduktion und progredienter systolischer Kompression des Gefäßes zeigte, wurde die Muskelbrücke über ihren gesamten Verlauf mit zwei weiteren Stents versorgt. Ein vierter Stent wurde in die proximale Läsion implantiert. Sowohl angiographisch als auch im ICUS ließ sich daraufhin die systolische Kompression nicht mehr nachweisen. Die CFGR verbesserte sich auf 3,3. In der Kontrollangiographie nach sechs Monaten stellte sich eine interventionsbedürftige Restenose im Stentbereich bei deutlicher Intimahyperplasie dar. Die ICUS-Untersuchung zeigte jedoch alle Stents zirkulär und voll entfaltet ohne Zeichen einer Kompression durch die Muskelbrücke. In a 64-year-old male patient with severe angina pectoris (CCS III) a systolic compression caused by a coronary muscle bridging in the left anterior descending artery could be detected by coronary angiography. Intravascular ultrasound (IVUS) as well as intracoronary Doppler examination showed a significant systolic reduction of the cross-sectional luminal area of 35.9% and a reduced coronary flow velocity ratio (CFVR) or 2.6. Two highly significant stenosis were detected proximal and distal of the muscle bridge. Percutaneous transluminal coronary angioplasty was performed at the distal lesion, resulting in a flow reducing dissection, and therefore subsequently a stent implantation was performed. Since the transition between the stent and the muscle bridge showed a severe flexion with continued systolic compression of the vessel, two further stents were employed to reinforce the entire area of the muscle bridging. A fourth stent was implanted in the proximal lesion. In the following angiographic and IVUS examinations a systolic compression was not detectable and the CFVR increased to 3.3. In the 6 months follow-up coronary angiography a restenosis in the stented area by intimal hyperplasia could be observed. However, IVUS showed all stents to be circular and fully expanded without signs of compression by the muscle bridge.

Parametric assessment of myocardial perfusion during interventional cardiac catheterization by means of X-ray densitometry — short — and long-term results

SummaryX-ray densitometric evaluation of digital subtraction angiocardiograms allows an assessment of myocardial perfusion by means of the parameter ‘MEAN RISE TIME’ (MRT), defined as the time from the onset of local myocardial contrast medium opacification to the point of maximum opacification. Best results are obtained when the response of that parameter is compared before and after stimulation of coronary flow by papaverine. A prolongation of this parameter, especially after papaverine, was indicative of an impairment of myocardial perfusion, when compared to the results obtained by TL-201 scintigraphy.In 50 patients with single vessel coronary artery disease the results of MRT pre and post papaverine before and after coronary angioplasty, as well as after 6 months were evaluated for 204 post-stenotic regions-of-interest. Before angioplasty papaverine induced a significant prolongation of post-stenotic MRT (2.3s ± 0.9s vs. 3.1s ± 0.8s; p<0.01), while after successful angioplasty post-stenotic MRT was measured significantly shorter after stimulation of coronary flow (2.6s ± 1.0s vs. 1.9s ± 0.9s; p<0.01). This indicated an improvement in myocardial perfusion. Nevertheless, 16/50 patients still presented pathological results of post-stenotic MRT after papaverine, although angioplasty was regarded successful. These patients presented a markedly higher rate of restenosis (14/16 patients after 6 months), a higher rate of dissections at the dilatation site and a higher rate of dilated vessels, supplying myocardial areas after a Q-wave myocardial infarction.Thus, these results demonstrate the additional information about the short-and long-term outcome of an angioplasty procedure by densitometric myocardial perfusion analysis.

Computerized estimation of quality standards for the X-ray densitometric assessment of myocardial perfusion

The densitometric evaluation of heart-phase-gated digital subtraction coronary angiograms derives different parameters which provide information about coronary blood flow, myocardial perfusion, and coronary flow reserve: appearance time, rise time, mean ascending time, and maximum intensity. The reliability and reproducibility of these measurements and of the derived parameters were investigated. Four digital subtraction coronary angiograms were obtained in ten patients, including two baseline measurements and two measurements under hyperemia induced by papaverine ic. Different reproducibility results were found for the parameters, depending on the heart phase of the densogram (diastolic better than systolic) and the region of interest (ROI) (septal ROIs revealed better reproducibilities than apical). Results under hyperemia were improved compared to baseline. Best results were obtained for rise time and mean ascending time, while the worst result was obtained for maximum intensity. In general, the reproducibility was poor but was markedly improved when the parameters were calculated from quality checked densograms.<<ETX>>